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BANDY, Le Roy Wilson, 1940- . THE BIOACCUMULATION AND TRANSLOCATION OF RING-LABELED CHLORINE-36 DDT IN AN OLD-FIELD ECOSYSTEM.
The Ohio State University, Ph.D., 1972 Ecology
University Microfilms, A XEROX Company, Ann Arbor, Michigan THE BIOACCUMULATION AND TRANSLOCATION OF
RING-LABELED CHLORINE-36' DDT IN AN OLD-FlELD ECOSYSTEM
DISSERTATION
Presented in Partial F ulfillm ent of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University
By
Le Roy W. Dandy, B.S., M.S.
x x x x x x
The Ohio State University
1972
Approved by
^Advii^ar Department' cf Zoology PLEASE NOTE:
Some pages may have
Indistinct print.
Filmed as received.
University Microfilms, A Xerox Education Company ACKNOWLEDGEMENTS
A number of Individuals and organizations have contributed to the successful completion of this project. The project was supported through a grant from the U.S. Atomic Energy Commission. The Ohio
Cooperative W ildlife Research Unit provided the essential laboratory fa c ilitie s , vehicles, and fie ld equipment. In addition, I have been the recepient of a Wildlife Unit research assistantship during the course of my graduate studies at the Ohio State University. The research s h e on the Urbana W ild life Area as well as a wide variety of equipment was provided by the Ohio Division of Wildlife. To these organizations
I would like to express my thanks.
I would like to express my appreciation to my advisor, Dr. Tony
J.Peterle, for his interest, advice, and assistance throughout this p ro je c t.
I would'also like to thank Dr. T. A. Bookhout, Dr. J. L. C rites, and Dr. L. S. Putnam fo r being members of my reading committee.
I would like to thank Charles W. Kellenbarger and Major David
Guest for their invaluable assistance in applying the insecticide to the study site.
Rodger K. Burnard and Dr. Sheldon Lustick gave valuable fie ld assistance during the early phases of the study. Laboratory and field assistance were also provided by Jacob VI. Lehman, Den ice D. Lustick,
Kaushalya Gursahaney, Marshal Moser, and Karl Karg.
The air sample apparatus was mado aval la b le 'fo r use in th is study by Lynwood Fiedler of the Ohio Department of Health. I would like to thank Tom Nash, manager of the Urbana W ild life
Area, fo r his valuable assistance and cooperation.
Insect identification was provided by Dr. C. A. Triplehorn,
Dr, J. N. Knull, Dr. D. DeLong, Dr. E. Thomas, Dr. G. E. B all, Dr. R. L.
Berry, and D. G. Furth of the Ohio State University Entomological
Museum.
Lastly, to my wife, Barbara, I would like to express my thanks
fo r her encouragement and assistance during the course of the study and the preparation of the dissertation.
in CONTENTS
Acknowledgements ...... n
Contents ...... lv
Tables ...... v I
Figures ...... xl
INTRODUCTION ...... I
Literature Review ...... 7
Description of Problem and Objectives , , 20
PROCEDURE ...... 22
Radioisotope Labeled DDT ...... 22
Description of Study Site ...... 27
Formulation and Application of Insecticide 36
Liquid S c in tilla tio n Spectrometry .... 46
Samp Ie Col le c t io n ...... '. . . 51
S ta tis tic a l Treatment of Data ...... 57
Background Radiation Levels ...... 57
Vegetation Biomass Determination .... 58
Calorimetry ...... 58
Ai r Samp Ii n g ...... 62
Study Pond Monitoring Procedure ..... 66
Gas Chromatography ...... 69
RESULTS ...... 71
Vegetation Residue Data ...... 71
Invertebrate Residue Data ...... 80
tv Ver+ebra+e Residue Data ...... 90
Study Pond Monitoring Data ...... 130
Vegetation Biomass Data ...... 136
A ir Sampling D a ta ...... 145
Calorimetry D a ta ...... 145
Gas Chromatography D a ta...... 145
DISCUSSION...... 149
DDT Contamination of P lants ...... 149
DDT Concentration by Invertebrates ...... 151
Small Mammal DDT Storage Patterns ...... 152
Ecosystem Comparison of Small Mammal Residue Data ...... 158
DDT Accumulation in S h re w s ...... f59
Blarina Home Range and TissueDDT L e v e l s ...... 163
Old-Field DDT CompartmentaIization ...... 167
Transfer of DDT to Avian P r e d a to rs ...... 180
SUMMARY...... 192
LITERATURE CITED ...... 197
APPENDIX...... 206
v TABLES
Comparative information on the physical characteristfcs of carbon-14, tritium, and chlorine-36 ...... 24
Summary of 1969 temperature and precipitation data, Urbana, Champaign County, Ohio ...... 31
Liquid scintillation spectrometer optimal gain setting fo r mammalian tissue samples ...... 47
Liquid scintillation spectrometer optimal gain settings for avian and reptilian tissue samples ...... 48
Liquid scintillation spectrometer optimal gain settings fo r herbaceous vegetation tissue samples ...... 48
Summary of variations In background radiation levels occurring between samples of control and study area vegetation (leaves) during 1968 ...... 72
DDT residue levels in the leaves of study area vegetation, 1969 ...... 74
DDT residue levels in the roots of the Wild Carrot (Daucus carota) , Urbana Study Area, 1969 ...... 79
DDT residue levels in the invertebrate species collected on the Urbana Study Area, 1969 ...... 85
DDT residue levels in the tissues of the short-tailed shrew (Blarina brevicauda), Urbana Study Area, 1969 ...... 93
Total body burdens and to ta l body residue levels of DDT In the short-tailed shrew (Blarina brevicauda), Urbana Study Area, 1969 ...... 96
Micrograms of DDT present in the tissues and the total body of the short-tailed shrew (.Blarina brevicauda), Urbana Study Area, 1969 ...... 97
Mean percentage of the body weight and weights of individual tissues of the short-tailed shrew (.Blarina brevicauda) . . 98
DDT residue levels' in the tissues of the masked shrew (Sorex cinereus), Urbana Study Area, 1969 ......
vr Tab le Page
15. Total body burdens and to ta l body residue level s ’of DDT In the masked shrew (.Sorex cine reus) , Urbana Study Area, 1969 ...... 101
16. Micrograms of DDT present in the tissues and the total body of the masked shrew CSorex cinereus), Urbana Study Area, 1969 ...... 102
|7; Mean percentage of the body weight of individual tissues of the masked shrew (Sorex cinereus? ...... 102
18. DDT residue levels In the tissues of the-meadow vole (Mlcrotus pennsyI van i cus) , Urbana Study Area, 1969 ...... 105 £, 19. Micrograms of DDT present In the tissues and total body of the meadow vole (Microtus pennsyI vanicus), Urtana Study Area, 1969 ...... 108
20. Mean percentage of the body weight and weights of individual tissues of the meadow voletMicrotus pennsyIvanicus) . . . 109
21. DDT residue levels in the tissues of an adult female mink (Mustela vison), Urbana Study Area, June 20, .1969 .... I ll
22. DDT residue levels in the tissues of juvenile mink (Mustela vison), UrbanaStudy Area, June 19 through June 23, 1969 112
23. DDT residue levels in the tissues of adult and juvenile mink (Mustela vison), Urbana Study Area, June 19 through June 23, 1969 ...... ' . . 113
24. DDT residue levels in the tissues of cottontail rabbits (Sylvtlagus floridanus), Urbana Study Area, 1969 ...... 115
25. DDT residue levels in the tissues of the wood mouse (Peromyscus leucopus), Urbana Study Area, 1969 J. 120
26. DDT residue levels in the tissues of adult red-winged blackbirds (Aaelaius phoeniceus), Urbana Study Area, June 19, 1969 (9 days p o s t- a p p lic a tio n ) ...... 122
27. DDT residue levels in the tissues of the ring-necked pheasant (Phasianus col chicus), Urbana Study Area, 1969. . 125
28. DDT residue levels in the tissues of the garter snake (Thamnoph i s s i rt a I is ), Urbana StudyArea, 1969 ...... 129
29. DDT residue levels In study pond vegetation,Urbana W ildlife Area, 1969 ...... 131 vtl Tab te Page
30. DDT residue levels' in study pond Insecta, Urbana W ild life Area, 1969 ...... 132
3!.' DDT residue levels in study pond vertebrates, Urbana Wi Id I tfe Area, 1969 ...... 133
32. DDT residue levels in the tissues of adu11 bu11frogs CRana catesbeiana), Urbana W ildlife Area, 1969 134
33. Peak biomass and per cent of total vegetation biomass represented by individual species ...... 138
34. Vegetation biomass data derived from c lip -p lo t samples collected during 1969, Urbana W ild life Area ...... 139
35. Climatotogical data collected in association with a ir samples, Urbana Study Area, 1969 142
36. Climatological data collected in association with air samples, Urbana Study Area, 1969 146
37. Caloric values for the muscle tissue of the short-tailed shrew (Blarina brevicauda? and for the whole bodies of selected invertebrate species ...... 147
38. Pre-application DDT residue levels In the short-tailed shrew (Blarina brevicauda) and the masked shrew (Sorex clnereus) collected on the Urbana Study Area, 1969 148
39. Summary of the probable levels of DDT consumed per gram of body weight by the short-tailed shrew (Blarlna brevicauda) and the masked shrew (Sorex cinereus) on d iffe re n t prey diets ...... 163
40. Mean radiation and DDT levels within the home range and DDT residue levels in the liver and skeletal muscle of Individual short-tailed shrews (Blarina brevicauda), Urbana Study Area, 1969 ...... 165
41. Relationship between home range ra d io a ctivity, home range DDT levels, and DDT residue levels in the liver and skeletal muscle of the short-tailed shrew (.Blarina brevicauda), Urbana Study Area, 1969 166
42. Estimate of DDT compartmentalized in the study area herbaceous vegetation (aerial portion) based on residue levels in individual species during the time of peak biomass ...... 171
vtt( T a b le Page
.43. Estimates of DDT compartments 11zation In the major components of the o ld -fte Id ecosystem ...... 178
44. Weight of the nondIgestible and the digestible portions of the carcasses of sma I I ' mamma I prey s p e c ie s ...... 181
45. DDT transfer from old-fleld'smaI I mammals to avian predators feeding on separate diets of each prey sp e cie s ...... 184
46. DDT transfer from o ld -fie ld small mammals to avian predators based on the spring-summer food habits data by Craighead and Craighead (1956) 187
47. List of vegetation occurring on study area, Urbana Wildlife Area, Champaign County, Ohio, 1968 and 1969 ...... 206
48. List of insects occurring on study area, Urbana Wildlife Area, Champaign County, Ohio 1968 and 1969 ...... 210
49. Partial list of invertebrate species (excluding insects) occurring on study area, Urbana W ildlife Area, Champaign County, Ohio, 1968 and 1969 ...... 216
50. List of vertebrate species occurring on study area, Urbana W ild life Area, Champaign County, Ohio, 1968 and 1969 .. . 217
51. Chlorine-36 labeled DDT radioactivity levels occurring at petri dish sampler stations, Urbana Study Area, June 10, 1969 219
52. Background radiation levels fo r study area and control area vegetation (leaves), Urbana W ildlife Area, 1968 ...... 223
53. Background radiation levels for control vegetat^n (leaves) Urbana W ild life Area, 1969 ....230
54. Background radiation levels for invertebrate sp ool I ected during 1968 and 1969 on the Urbana W lioi. a A r e a ...... 233
55. Background radiation levels for the tissues of the short- tai led shrew (.Blarina brevicauda) collected during 1968 and 1969 on the Urbana Wi Id life A r e a ...... 234
56. Background radiation levels for the tissues of the masked shres CSorex cinereus) collected during 1968 and 1969 on the Urbana Wildlife A rea ...... 235
fx T a b le Page
57. Background radiation levels'for the tissues of the meadow vole' CMicrotus pennsyIvanicus), Urbana W ild life Area, 1969 ...... 235
58. Background radiation levels'for the tissues of the cottontail rabbit CSylvllagus floridanus), Urbana Wildlife Area, 1969 ...... 236
59. Background radiation levels for the tissues of the mink (Mustela vison) ...... 237
60. Background radiation levels for the tissues of the wood mouse (Peromyscus ieucopus) collected during 1968 and 1969 on the Urbana W ild life A re a ...... 238
61.- Background radiation levels for the tissues of the red winged blackbird (Aqelaius pheonlceus), Urbana W ildlife Area, 1969 ...... 239
62. Background radiation levels for the tissues of the garter snake (Thamnoph1s s ir t a lis ), Urbana W ild life Area, 1969. . 239
63. Background radiation levels for the tissues of the ring- necked pheasant (Phasianus coIchicus) , pen-raised controls, 1969 ...... 240
64. Background radiation levels for the study pond control flo ra and fauna, Urbana W ild life Area, 1969 241 FIGURES
Figure Page
1. Structural formulas of DDT and the major DDT metabolites depicting the phenyl ring position of the chlorine-36 radioisotope label ...... 25
2. Topographic map of the study area, Urbana W ild lffe Area, Champaign County, Ohio ...... 29
3. Shed located adjacent to study area which v/as used as a field laboratory and storage facility ...... 34
4. Radio-controlled, gasoline-powered rotary applicator used to apply insecticide to study area ...... 38
5. Helicopter and applicator en route to study area .... 38
6. DDT-impregnated granules being applied to study area . . 40
7. Vaseline-coated petri dish granule sampling device anchored to stand prior to application ...... 42
8. Distribution of chlorine-36 labeled DDT as indicated by 78.5 cm2 petri dish sampling d e v ic e s ...... 45
9. A ir sampling device in place on study a r e a ...... 63
10. DDT storage patterns in the meadow vole (Mlcrotus pennsyIvanicus) and the masked shrew (Sorex cinereus) during the 1969 growing season ...... 153
11. DDT storage pattern in the short-tailed shrew (Blarina brev Icauda) during the 1969 growing season ...... 154
xl INTRODUCTION
The flow of energy through a biological system, according to
Morowitz (1968), acts in such a way as to impart organization to that
system. A il levels of biological organization ranging from the molecular
and cellular levels to the population and ecosystem levels conform to
th is concept. The pattern of energy flow through the system and the
degree of organization which results depend upon the structural and
functional complexity of the ecosystem (Margalef, 1963; Odum, 1969).
The complexity of ecosystem structure and function, in turn, determines the stability of that system to external perturbations imposed upon it
by the physical environment (MacArthur, 1955; Odum, 1969).
An ecosystem having a high degree of complexity is characterized by high species diversity and equitabiIity, a closed intrabiotic
nutrient cycle, a decreased rate of energy flow per unit of biomass, web-like food chains, and well developed internal symbiotic relation ships. The components of the system interact, thereby providing for
feedback mechanisms which promote s ta b ility to external perturbations
(Pimentel, 1961; Odum, 1969). An ecosystem having a low degree of complexity would be characterized by low species diversity and equitability, an open extrabiotic nutrient cycle, a large flow of energy per unit of biomass, simple linear food chains, poorly developed
internal symbiotic relationships, and poor component interaction and stability to external factors.
I 2
Pollution resulting from intensive industrial and agricultural exploitation exerts a direct influence on the structural and functional complexity of an ecosystem. In general, pollutants promote the s im p lifica tio n of ecosystems (Woodwell, 1970). Species d iversity and e q u ita b ility are decreased. Trophic structure is shifted in favor of larger numbers of organisms representing a small number of species occupying positions near the food chain base. Consequently, food chains are shortened and become more linear rather than web-like. The loss of nutrients beyond the confines of the system is accelerated, thus leading to eventual nutrient impoverishment. Larger amounts of energy are required per unit of biomass. Few symbiotic relationships exist. Feed back mechanisms essential fo r stable interactions between ecosystem components are poorly developed or lacking. The end product of such pollution-induced changes is the loss of the stability possessed by complex systems. Plant and animal populations fluctuate widely in response to both naturally occurring and pollution-induced factors.
Insecticides, in spite of their short-term economic benefits, have had the same impact on ecosystem structure and function as have .• other forms of pollutants, that of promoting sim plificatio n and instability. The use of the ecologically narrow panacea, the insecticide, in agricultural and forestry has been necessitated by the prior ecosystem simplification caused by the over-exploitative practices of these industries. Evolving out of the desire to obtain maximum yields, the monocultures and near-monocultures of agriculture and forestry are by necessity highly simplified and unstable. Insect population irruptions are more probable under such conditions than in more diverse natural 3 systems (Pimentel, 1961 and 1970; Turnbull, 1967). Under unstable conditions of th is type, widespread insecticide usage has become the accepted means used to control insect population outbreaks and to pro mote economic gain. Examples of the disruptive effect of insecticides on ecosystem structure and function are provided in the following studies.
In a comparative investigation of invertebrate populations in the litte r and soil of insecticide-treated and untreated orchard grassland sites, Menhinick (1962) found evidence of chemically-induced ecosystem disruption. On insecticide-treated sites, the diversity and to ta l biomass of the l it t e r and soil invertebrates were decreased.
Trophic structure underwent a s h ift in favor of a larger number of smaller, lower trophic level organisms (collembola, sarcoptiform mites and aphids). There was an accompanying reduction in the number of larger predaceous invertebrate species (Chilopoda, Araneida, predaceous
insects); the larger primary consumers (Diplopoda, Oniscoidea and
Symphyla) also were reduced in numbers. Although only the structural changes in the grassland system brought about by insecticide treatment were investigated, Menhinick stated that such structural changes should also produce functional changes accompanied by decreased s ta b ility .
Barrett (1968) investigated the effects of the carbamate
insecticide Sevin on the productivity, density, diversity and equit- a b ility of the b io tic components of a grain crop grassland ecosystem.
The outstanding finding of this study emphasized that the effects of the insecticide treatment on community structure were detectable long after the insecticide residues had disappeared. The insecticide 4 significantly reduced the rate of litte r decomposition, apparently as the result of the reduction or elimination of the soil microbes and arthropods. Such a disruption could have affected mineral cycling, although this aspect was not measured. The insecticide had no detect able effect on net community primary production in the monoculture system of browntop m ille t (Fanicum ramosum).
The to ta l biomass and numbers of arthropods were reduced on the treated site as much as 95 percent below that of the control area.
Insect d iv e rs ity , in general was reduced. D iversity among phytophagous species was reduced but returned to control levels within 2 weeks post application. However, d iversity among predaceous insects was depressed for 5 weeks following the insecticide treatment. Diversity among spiders was not decreased, although numbers were reduced. The community structure of the mammalian component of the grassland ecosystem was also disrupted as a result of an insecticide-induced delay of reproduc tion in the cottonrat (Sjgmodon hispidus).
Malone (.1969) conducted an investigation of the structural
responses of an old-field ecosystem to an application of the organo- phosphate insecticide diazinon. Fauna! sim plificatio n occurred among the herb-stratum insects and was attributed to the adverse effect of the insecticide on insect species having a soil-related life history stage. However, simplification is apparently not the only ecosystem
response characterizing an area treated with an organophosphate
insecticide. During the f i r s t growing season, increased species diversity, total density and net production were observed in the vegetation of the treated area. In addition, the Hemiptera on the 5
treated site exhibited greater diversity than did the same group on
the control area. The increase in Hemipteran diversity resulted as a
response to insecticide-induced changes in the treated area vegetation.
The suggested causes fo r the flo r is t lc changes were 1) the insecticide
control of phytophagous soil invertebrates (nematodes and wireworms)
which are capable of influencing plant competition and population
structure, 2) the differential response of the old-field vegetation to
the phytotoxic properties of diazinon, and 3) Hie fertilizer effect
associated with the breakdown of the organophosphate Insecticide.
The density of soil microarthropods was depressed to zero
immediately after the insecticide treatment but recovered by the end
of the growing season. Conversely, an increase in the rate of detritus
disappearance was noted. Insecticide stimulation of bacterial growth
was offered as an explanation for th is phenomenon. During the second
year post-application, the old-field ecosystem had equilibrated with
the control area.
Attempting to duplicate the results obtained by Malone (1969)
and to isolate the causative mechanisms, Shure (1971) undertook a
similar study. Diazinon was applied to an old-field study plot during
the growing seasons of 1967 and 1968. Increases in vegetational
d iv e rs ity , density and total biomass were observed on the treated area
in 1967. However, no vegetational differences were detected between
the treated and control areas during 1968. The vegetational response
during 1967 was attributed to the phytotoxic effect of diazinon on the
dominant and in h ib itin g species of bindweed. Convolvulus sepium. No
detectable differences among treated and control herb-stratum arthropod 6 populations were found. The f lo r is t ic changes failed to produce an accompanying change in phytophagous insect species as occurred In the study by Malone (1969). Therefore, If diazinon can be taken as repre sentative of a ll organophosphate insecticides, the ecosystem effects involve both simplification and stimulation. The latter effect is apparently either unique to this group of insecticides or is an unmeasured or masked condition characterizing insecticides in general.
The studies by Barrett (1968), Malone (1969) and Shure (1971) represent the most recent and extensive investigations of the ecological effects of insecticides on the so-called nontarget biota of intact ecosystems. The extent and degree to which the structural and functional in te g rity of an ecosystem is disrupted apparently are d ire c tly propor tional to the persistence of the insecticide. The organochlorine insecticides (the cyclodiene compounds which include dteldrin, aldrin and endrin and the diphenyl alip hatic compounds which include DDT and
Its analogs) represent the most persistent and ecologically most d isruptive insecticidal compounds. The use of the carbamate and organophosphate insecticides in the la tte r studies was necessitated by the desire to obtain data encompassing both the in itia l effects and the long-term effects on the ecosystem following the breakdown of the
Insecticide. The long breakdown period associated with the organo ch lorine compounds would have made an investigation of the long-term effects impractical. 7
Literature Review
Among the persistent organochlorine insecticides, the most prominent compound from the standpoint of global contamination and ecological hazard as well as economic and political controversy, is
2,2-bis (p-chlorophenyi)-l, I, l-trichloroethane, commonly referred to as
DDT. Although the Insecticide was firs t snythesized in 1874 by the
German chemist Othmar Zeidler, the insecticidal properties of DDT were not recognized u n til 1939 by Paul Muller of the Geigy Company of
Switzer land. After having been proven e ffe ctive against the typhus epidemics of Ita ly in 1943 and 1944, DDT was released fo r public use shortly a fte r the end of World War II. The optim istic promises of the complete eradication of a 11 insect pests resulted in the immediate and widespread usage of DDT. Muller was awarded the Nobel Prize in Medicine il in 1948 for his contribution.
Although the promises of pest eradication have since been shown to be somewhat over-optimistic, DDT has until recently been the major product of the global insecticide industry. At present, the use of DDT has been more or less curtailed in Europe and in North America due to concern over the insecticide's role as an ecological and possible health hazard. Its use elsewhere remains substantial due to the e ffo rts of the
United Nations and various other groups to control malaria in the underdeveloped countries. Because of its persistence and mobile nature and its use in disease vector control programs, the lim itations placed on the usage of the compound in North America and Europe have not decreased the status of DDT as a global pollutant. 8
The status of DDT as an insecticide and as a global contaminant
is d ire c tly related to its physical and chemical properties. The
popularity of DDT as an insecticide can be attributed to the following ch a racteristics: I) maximum persistence, 2) high potency and non
specificity as a poison, and 3) low production costs. The persistent
nature of DDT is attributed to its high degree of chemical stability, being extremely resistant to breakdown by sunlight and weathering. In addition, the low volatility of the compound (vapor pressure of
1.5 x 10 ^ mm Hg at 20°C) (Balson, 1947) also contributes to the persistence of the insecticide (Brown, 1951). DDT, being an apolar compound, is practically insoluble in water (1.2 parts per billion,
Bowman, et a l., I960). However, as an apolar compound, it is highly soluble in lipids. The latter characteristic is responsible for the accumulation of the insecticide in the fatty tissue of living organisms,
for its magnification through community trophic structure, and, consequently, for its potential as an ecological hazard. As a non specific poison, DDT is ideally suited for use against a wide range of pest species. Yet, the nonselectivity of DDT contributes to its ecologically disruptive role.
DDT is an omnipresent contaminant of global ecosystems. Sladen,
Menzie, and Reichel (1966) and George and Frear (1966) reported detectable quantities of DDT in the water, fish, birds and mammals of
Antarctica, an area which is remote from the nearest point of DDT application and an area which has no record of insecticide application.
Tatton and Ruzicka (1967) in a later investigation of DDT contamination of Antarctica confirmed and broadened the findings of the earlier 9
investigators. Similar studies have shown DDT to be present in the fauna of atI major land masses and In most marine areas.
DDT may be translocated from the point of application to other portions of the earth by any of several possible mechanisms. The
insecticide may leave the application site either by codistillation with water (Acree et al., 1963) or by vaporization (Lloyd-Jones, 1971) and then be deposited elsewhere in association with dust particles or rain. Particulates associated with DDT on the application site may become airborne and may be either carried to a new site directly or to the ground in ra in fa ll (Risebrough et a l., 1968; V/e i be I et a l., 1966).
The loss of DDT through drift during an aerial application also provides a means by which the insecticide could become airborne and then trans ported to other areas (Hind in et a I., 1966). The fact that DDT does become an atmospheric contaminant has been well documented by a number of investigators (Wheatly and Hardmann, 1965; Antommaria et a l., 1965;
Abbott et a !., 1966; Cohen and Pinkerton, 1966; Tabor, 1966; Tarrant and Tatton, 1968).
DDT attached to particulate matter at the site of application may be transported to other locations by a stream or by ocean currents
(Hickey et a I., 1966; Risebrough e t a I., 1957 and 1968; Woodwell et a I.,
1967; Dimond et al., 1968). Biological transport of DDT from distant points is also possible. Migratory species may accumulate the insecticide while on the wintering or breeding grounds, migrate, and then redeposit the DDT at a new location by means of their excreta or th e ir decomposing bodies (Tatton and Ruzicka, 1967). 10
The action of DDT in inducing ecosystem simplification may at
times be quite obvious as the result of conspicuous mass m ortality
among non-target organisms. Soon after the release of DDT for public
use, large die-offs of nontarget vertebrate and invertebrate species
were frequently observed in areas treated with the insecticide. Heavy
mortality among robins CTurdus migratorius) and other songbirds has been
reported by a number of investigators in areas where DDT was used in
attempts to control the Dutch elm disease (Baker, 1958, Hickey and Hunt,
I960; Wallace, 1962; Wurster et a I., 1965). In C alifornia heavy m o rtality among the western grebe (Aechmophorous occidentaIis) was
reported by Hunt and Bischoff (.I960) as the result of the application of DDD, an insecticidal metabolite of DDT, to Clear Lake for purposes of controlling the Clear Lake gnat (Chaoborus astictopus). Die-offs of salmonid fishes have been reported in areas where DDT was used to control
forest insect pests (Keen leyside, 1959; Burdick et al., 1964). Similar sprayings were responsible for the elimination of invertebrate food species in salmon and tro ut streams in the United States and Canada
(Cope, 1961: Ide, 1956). M ortality among amphibians has also been observed following applications of DDT (Fashingbauer, 1957).
Although mortality resulting from acute poisoning represents the most conspicuous ecosystem disrupting e ffe ct of DDT, the action of the insecticide at sub lethal dosage levels represents the most significant and far-reaching effect on the biosphere. The effect of
DDT on net primary productivity In marine ecosystems represents one of the more subtle, yet potentially most catastrophic, effects of the
insecticide. Wurster Cl968). demonstrated that DDT at low concentrations (parts per b illio n range) could reduce the photosynthetic rate of marine
phytoplankton 30# to 40# below normal. Since the species studied by
Wurster were representative of the most abundant and widely distributed
groups of marine phytoplankton (groups which serve as the base of many
marine food chains), the consequences of such p o llution are obvious.
Cox (1970) reported that marine phytoplankton collected in Monterey Bay,
California, have undergone a three fold increase In p,p'-DDT and its metabolites p jp ’ -DDD and p,p'-DDE between 1955 and 1969. The higher
residue levels of DDT found in higher trophic level marine organisms
at diverse points by other investigators (Risebrough et a I., 1967;
Risebrough, 1969; Wurster and Wingate, 1968) suggest that the structural
and functional complexity of marine systems may have already undergone
degenerative changes.
DDT-induced avian reproductive failure is another manifestation
of the attrition of ecosystem structure and function currently coming
to lig h t. For approximately the past two decades, certain avian species
populations in both North America (Hickey and Anderson, 1968) and Europe
(R a tc liffe , 1967) have undergone sharp declines in numbers. The major
portion of these species share a common characteristic of being either
raptorial or otherwise occupying top trophic positions. This particular trophic position is conducive to high exposure to organochIorine
insecticide residues through biological magnification. Residue data are now available which implicate DDT and DDE with the declining
populations of a number of North American avian species; included among these species are the bald eagle (Haliaeetus leucocephaI us; Hickey and
Anderson, 1968), osprey (Pandion ha Iiaetus; Ames, 1966), peregrine 12 falcon (Falco peregrlnus; Hickey, 1969), double-crested cormorant
(Phalacrocorax a u ritu s; Anderson et a I., 1969), brown pelican CPelecanus occidentaI is; Keith et al., 1970; Blus, 1970), herring gull (Larus argentatus; Hickey and Anderson, 1968), and the western grebe (Aechmophorus occi denta M s; Herman et a I., 1969). The pelagic Bermuda petrel (Pterodroma cahow) also has undergone a decrease in population size during the
last decade and carries sizable quantities of DDT CWurster and Wingate,
1968). In Europe the following species fall into the above category: the golden eagle CAqu tII a chrysaetos; Lockie et a I., 1969) sparrow hawk (Accipiter nisus; Ratcliffe, 1967), and peregrine falcon (Hickey,
1969). Additional species on both continents are locally declining in numbers; however, in su fficie n t analytical work has been performed to
implicate DDT or other organochlorine insecticides (Wurster, 1969).
In general, the reproductive failure and subsequent decline of the above species have been associated with any or all of the following field observations: I) the abandonment of long-standing breeding te rrito rie s (centuries old in some cases), 2) increased egg breakage due to shell thinning, 3) egg eating by parents, 4) delayed breeding,
5) fa ilu re to lay eggs, and 6) high m ortality among embryos and fledglings (R a tc liffe , 1970; Hickey, 1969; Keith, 1966; Ames, 1966;
Herman e t a I., 1969; Keith et a I., 1970; Ludwig and Tomoff, 1966;
Wurster and Wingate, 1968; Blus, 1970; Fox, 1971; Cade et a I ., 1971).
These observations of behavioral and physiological abnormalities have been correlated with the simultaneous presence of high body burdens of the organochlorine insecticides, especially DDT and its metabolites and d je ld rin . Using eggshell collections from the period before the advent 13 of the organoch lori ne insecticides and afterward, R a tcliffe (.1967) in
Europe and Hickey and Anderson (1968) in North America demonstrated a strong correlation between the time the insecticides came into general use and the onset of eggshell thinning.
Reproductive failure Is usually more prominent among species or populations having behavioral characteristics which favor higher levels of environmental organochlorine insecticide exposure. Most species experiencing reproductive failure are either migratory, or otherwise highly mobile populat!ons,or stationary populations residing in areas of high organochlorine exposure. Lockie et a I., (1969) reported that reproductive success was normal among golden eagles in eastern Scotland where exposure to DDT and d ie ld rin was low; however, the same species experienced reproductive failure (characterized by eggshell thinning and egg breakage) and declined in numbers in western Scotland where
DDT and d ie ld rin exposure was high. These authors also observed a gradual improvement in the reproductive success of the eagle population in western Scotland following the replacement of DDT and d ie ldrin by the less persistent organophosphate insecticides, Hickey and Anderson
(1968), although observing eggshell thinning in declining populations of peregrine falcons, bald eagles, and ospreys (species normally considered migratory), detected no eggshell thinning among stationary populations of red-tailed hawks (Buteo jamaicensis), great-horned owls
(Bubo vi rginianus?, or golden eagles. The la tte r species populations are assumed to have occurred in areas of low organochlorine exposure.
The eggshell thinning phenomenon observed under fie ld conditions has been duplicated in the laboratory with captive avian populations 14
fed diets containing DDT, DDE, and dieldrin, either in combinations or
alone. Diets containing low levels of combined DDT and dieldrin were shown by Porter and Wiemeyer (1969) to cause eggshell thinning in the
kestrel (FaIco sparverius) . A (ater study by these investigators
(V/iemeyer and Porter, 1970) demonstrated that p,p'-DDE, a widespread and normal metabolite of p,p'-DDT,caused eggshell thinning when fed alone in the diet of the kestrel. Apparently, DDE, although having a much lower acute to x ic ity than DDT, has greater a b ility to cause eggshell thinning than does DDT. Heath et a l. (1969) observed a reduction in reproductive success among mallards (Anas platyrhynchos) fed low level diets (10 ppm) of DDE. The eggs produced by these experimental mallards were thin-shelled, bore numerous hair-line cracks, and displayed a decreased level of hatchability when compared with controls. Similar results were obtained by Longcore et a I. (1971) for captive black ducks (Anas rubripes) fed diets containing DDE (10 ppm and 30 ppm). Eggshell thinning resulting from diets of DDT and DDE was also reported by Bitman et al. (1969) in coturnix quail (Coturnix coturnix) and by Enderson and Berger (1970) in the p ra irie falcon
(FaIco mexicanus) .
Several mechanisms have been hypothesized which would account for the action of the organochlorine insecticides (DDT, DDE and dieldrin in particular) in promoting the field-observed cases of avian reproductive failure. The induction of the hepatic oxidizing enzyme system by the ; organochlorine insecticides is one such mechanisms. The oxidizing enzyme system of the vertebrate liver provides a general mechanism by which apolar, aqueous-insoluble compounds may be eliminated from the organism via the kidneys in a polar and water-soluble form. This enzyme
system acts equally well on both biologically foreign compounds and
compounds produced by an organism as normal metabolites.
In appropriate quantities, most biologically active compounds
are nontoxic and essential for the normal functioning of an organism's
life-su stain in g processes. However, the same compounds in excessive
amounts can have toxic or otherwise deleterious effects. Compounds of
a nonbiological origin likewise can have the same effect when present
in excessive quantities. Under normal conditions the oxidizing
enzymes of the liver prevent the accumulation of biologically active
compounds beyond threshold levels, thereby maintaining homeostatic
conditions. The accumulation of foreign compounds, unless the compounds
are present in overwhelming amounts, is also prevented.
Certain nonbiological compounds have the ability to Induce the
hepatic mi crosomes to produce the oxidizing enzymes at higher than
normal levels. Under such conditions a ll compounds normally metabolized
by th is system are broken down at an accelerated rate. Unless rapidly-
acting feedback mechanisms are b u ilt into the system, a d e fic it of essential, Dio logically active compounds will occur. The inducer
compounds which stimulate an increased elaboration of oxidative enzymes
are detoxified by the same microsomal enzyme system. The a b ility of an
organochlorine insecticide to induce the production and increased rate of action of the hepatic oxidizing enzymes was firs t reported by Hart
et a l. Cl963). Chlorodane, accidentally applied to a room housing
laboratory animals, was found to increase the rate of enzyme production
and to increase the rate at which an experimentally administered drug 16
(hexobarbital) was metabolized in white rats. Consequently, the drug was broken down too rapidly to produce its expected e ffe ct. DDT has been observed to produce the same e ffect on drug metabolism (Hart and
Fouts, 1963).
Steroid hormone metabolism is also influenced by the action of
DDT on the hepatic oxidizing enzyme system CPeakall, 1967). Because of the nonspecific nature of the enzyme system, increased exposure to
DDT and its metabolites increases the rate of enzyme production and the rate of hydroxy I at ion of the steroid compounds. Through enzyme action, the biological activity of the hormones is altered. Since the repro ductive hormones, the estrogens, androgens, and progestins, are susceptible to alterations of this type, the phenomenon of insecticide
induction of hepatic enzymes has been given careful consideration as an explanation for the behavioral and physiological abnormalities observed to be associated with cases of avian reproductive fai lure.
The eggshell thinning phenomenon has been attributed by some
investigators to an estrogen-re Iated calcium deficiency brought about by the insecticide induction of the hepatic enzyrne system. Normally, estrogen is secreted at higher levels at the time of reproduction and exerts an influence over calcium metabolism in the following ways: I) estrogen promotes the increased absorption of calcium from the d ie t,
2) the excretion of calcium is decreased under the influence of estrogen,
3) estrogen promotes the deposition of calcium as medullary bone, and
4) estrogen promotes the mobilization of calcium from the medullary bone just prior to its deposition as eggshell calcium. If the critical estrogen levels were decreased through the action of DDT, DDE, or 17 dieldrin, an estrogen deficiency would result in a calcium deficiency which in turn would result in eggshell thinning.
A similar insecticide-promoted decrease in estrogen levels as well as the levels of the hormone progesterone could also explain the abnormal parental and general reproductive behavior associated with the eggshell thinning syndrome. Increased cases of egg-eating, late nesting or complete failure to nest, nest abandonment, and territorial abandonment could be explained by decreased estrogen and progesterone levels circu la tin g in the blood and by the subsequent in a b ility of these hormones to exert the appropriate influence over those portions of the central nervous system controlling such behavior.
Another mechanism hypothesized as being responsible for eggshell thinning is the DDT inh ib itio n of the enzyme carbonic anhydrase in the she I I-forming gland of the oviduct (Anderson et a l., 1969). The enzyme normally catalyzes the formation of carbonic ions prior to combination with blood calcium to form the eggshell caIciurn carbonate (Common, 1941;
Gutowska and M itchell, 1945). Although hepatic enzyme induction and the alteration of hormone levels do occur and are sufficient to affect reproductive behavior and calcium metabolism, most investigators now believe that DDT exerts its effect on eggshell thinning at a point nearer the s ite of eggshell formation. Peakall (1970) demonstrated that ring doves (StreptopeIia risoria) injected with p,p'-DDE within a day of egg-laying underwent a reduction in carbonic anhydrase a c tiv ity .
Duplication of the experiment using dieldrin had no effect on carbonic anhydrase a c tiv ity . Bitman et a l. (1970) also reported a 16 to 19 percent lowering of carbonic anhydrase activity In the shell-forming 18
gland of the coturnix quail fed p,p'-DDT and p,p’ -DDE.
The work of Dvorchik et al. CI97I), however, has cast considerable
doubt on the carbonic anhydrase in h ibitio n hypothesis as an explanation
for eggshell thinning. These investigators found that p,p’-DDT and
p,p'-DDE in vivo at concentrations simulating environmental levels (50
to 100 ppm) fa ile d to in h ib it the action of carbonic anhydrase, although
a partial inhibition was obtained at higher concentrations (500 ppm).
Dvorchik et al. Cl971) concluded that DDT was ineffective as an
in h ib ito r of the enzyme at normally encountered environmental concentrations.
Therefore, even though DDT has been strongly correlated with avian
reproductive fa ilu re , the mechanism, or mechanisms, involved have not
been clearly elucidated. The possibility exists that the shell thinning
phenomenon and its associated behavioral abnormalities may be either the product of different mechanisms individually active in separate
species, or the product of several mechanisms operating simultaneously to produce one end result.
DDT-induced reproductive failure apparently also occurs in fish.
Macek (.1968) demonstrated that yearling brook tro u t CSa I ve I i nus fonti na1 is ) fed sub lethal doses of DDT for 156 days produced fry which experienced higher mortality rates than did the progeny of control fish.
Death occurred in the progeny of the treated group at a time when the yolk sac was undergoing maximum utilization and the lipid-associated
DDT in the yolk v/as being mobilized. Extrapolation of the DDT-induced m ortality observed in the laboratory to sim ilar m ortality in wild populations was based upon similar residue levels in the treated fish at the end of the 156-day feeding period and in adult brook trout taken 19
from the w ild. Burdick et a l. C1964) observed sim ilar increased in
m ortality rates among the progeny of female lake trout (SaIveIinus
namaycush) captured from streams in DDT-sprayed watersheds.
Fish, like certain higher trophic level avian species, exhibit
DDT-induced behavioral changes which potentially could alter survival
rates in the w ild. OgiI vie and Anderson (1965) found that exposure of young A tla n tic salmon (SaImo sa I ar) to sub lethal doses of DDT (5 to 50
parts per billion) for a 24 hr period disrupted the temperature selection ca p ab ility of th is species. Low doses of DDT produced downward s h ifts
in the selected temperature whereas high doses produced upward s h ifts In the selected temperature. Such a behavioral disruption could con ceivably have a deleterious effect on reproduction through changes in
spawning behavior; decreased survival rates might also result from the influence of the insecticide on temperature-related habitat selection.
Anderson LI968) demonstrated that exposure' of the brook trou t to
sublethal levels of DDT (0.1 to 0.3 ppm) caused the lateral line nerve to be hypersensitive to mechanical disturbances. The effect was
discovered to be more pronounced at lower temperatures. DDT was found to interfere with the learning ability of brook trout (Anderson and
Peterson, 1969). Fish exposed to sublethal levels of DDT were prevented
from learning to avoid a preferred light condition. Previously conditioned
fish also experienced greater difficulty than control fish in retraining to the same stimulus after exposure to DDT. 20
Description of Problem and Objectives
In order to understand the effects of the organochlorine
insecticide on the structural and functional inte grity of ecosystems, basic data must in itia lly be made available concerning the accumulation
and translocation of known quantities of such compounds among the b io tic and a b io tic components of intact natural systems. This study was under taken to provide information of this nature for the insecticide DDT in an intact o ld -fie ld ecosystem. Isotope d ilu tio n analysis was the basic method employed to achieve this goal. Known quantities of technical grade DDT and a form of DDT labeled in the ring position with the
radioisotope chlorine-36 were formulated and applied to an old-field study plot. Radioactivity originating from the labeled DDT was measured
in samples of the old-field biota by means of liquid scintillation spectrometry; the actual residue levels of DDT present In the samples were determined on the basis of the known proportions of the labeled and nonlabeled compounds used in the original insecticide formulation.
The following individual objectives were set for the study:
1) The establishment of an enclosed 4 .05-hectare C10-acres) old-field study site.
2) The description of the flora and fauna occurring on the old-field study site.
3) The determination of the background radiation levels and pesticide burdens fo r selected species of o ld -fie ld flora and fauna.
4) The measurement of the rates of accumulation and translocation of chlorine-36 ring-labeled DDT in the old-field flora and fauna. 21
No attempt was made in this study to measure the levels of DDT present in the detritus, soil, or soiI-detritus biota. This objective was undertaken in a companion study conducted by Dr. D. L. Dindal of the State University College of Forestry, Syracuse, New York. PROCEDURE
Radioisotope Labeled DDT
Before a final commitment was made concerning the use of the
radioassay approach and chlorine-36 labeled insecticide, a number of
factors were carefully considered. To accurately measure the rates of translocation and bioaccumulation of the DDT in the various compartments of the o ld -fie ld ecosystem, the source of the compound being measured and the approximate time of its entrance into the system must be known.
The widespread occurrence of DDT and the stru ctu ra lly sim ilar and equally persistent polychlorinated biphenyl compounds (PCB's) in the biosphere precluded the use of the conventional pesticide analytical method of gas chromatography. If gas chromatography were used, no d istin ctio n could be made between the DDT applied in the present study and DDT having an extraneous origin. In addition, the possible presence of the PCB compounds in samples analyzed by gas chromatography would also have presented problems. The PCB's, being chlorinated compounds and having a molecular structure similar to that of DDT, produce chromatographic retention peaks which are identical with retention peaks produced by
DDT and its metabolites. Consequently, the PCB's tend to either mask or simulate the presence of DDT and its metabolites. Although these d iffic u ltie s could be overcove by various clean-up procedures and columns, the elim ination of the PCB compounds from the gas chromatography samples would have involved additional expenditures in time, labor, and money. Such problems could be avoided through the use of a radioisotope
22 23
labeled form of DDT and instrumentation such as liquid scintillation
spectrometry.
From the standpoint of economics and the efficiency of time,
the radioassay approach utilizing liquid scintillation counting greatly
surpassed analysis by gas chromatography. When the costs of labor and
reagents were compared, the cost of sample preparation and analysis by
gas chromatography exceeded the cost of sample preparation and analysis
by liquid scintillation spectrometry by a ratio of 6 : I. Costs total
approximately $20.00 fo r each gas chromatography sample and $3.00 for
each liquid scintillation spectrometry sample. Therefore, the use of
gas chromatography in an ecosystem-oriented study where 4000 to 5000
samples might be processed would have been prohibitive.
After the radioassay approach was chosen as the best analytical method for this particular study, the choice of the most appropriate
radioisotope was the next decision to be made. The important factors which were considered at th is point were I) the type of emmission, 2) the disintegration energy, and 3) the physical half-life. The choice of a radioisotope label for the insecticide DDT is, of course, limited to three elements, carbon, hydrogen, and chlorine. Among these three elements there exists a total of II radioistopes. However, only three, carbon-14, tritium, and chlorine-36, have half-lives sufficiently
long enough to be useful in the present study. All three isotopes are negative beta emmitters, a desirable characteristic from the standpoint of possible hazard to humans or the old-field biota. Additional infor mation concerning the physical characteristics of these three radio
isotopes is given in Table I. 24
Table 1. Comparat ive information on the physical characteristics of carbon-14, tritium , and chlorine- 36a.
Rad ioisotope Physical Disintegration Type Emission Ha 1 f-Li fe Energy (Mev)
Carbon-14 5760 years 0.156 Negative Beta
Tri t i urn 12.26 years 0.018 Negative Beta
Ch lori ne-36 3.03 x 105 0.710 Negative Beta years
aAI! data taken from S hill ing (1964).
After inspection of the physical characteristics of the three radioisotopes, chlorine-36 was chosen because of its higher disintegration energy level and its longer h a lf- life . The higher disintegration energy level would promote greater counting efficiency, whereas the long half- life would make decay corrections unnecessary.
The position of chlorine-36 on the DDT molecule was also an important consideration. The criterion determining the position of the radioisotope on the Insecticide molecule was the tenacity with which the chlorine atom is bound, and, therefore, the likelihood of premature removal from the compound during some stage of metabolism. If the chlorine-36 label had been attached to the ethane group of the molecule, the label would have been lost early in the breakdown of the compound to its various metabolites. Therefore, the alternate position on the phenyl rings Cp and p' positions) was chosen as the labeling site since chlorine in this position remains with all known metabolites of DDT (Fig. I).
The choice of a carbon-14 label in a phenyl ring position would also 25
c SQ- c h -Q c ,' C l
c h c i2 CCI DDD DDE
COOH DDA
Fig. Structural formulas of DDT and the major DDT metabolites depicting the phenyl ring position of the chlorine-36 radioisotope label.' 26 have given a label which would have been metabolleally stable; however, the low energy of emission of carbon-14 precluded th is p o s s ib ility .
A tritium label at any point on the molecule would have been impractical due to the extremely low energy of emission of this radioisotope. 27
Description of Study Site
Location and History - The study was conducted in Champaign County In west central Ohio on a portion of the 222-ha (548-acre) state-owned
Urbana W ild life Area. The Urbana Area, formerly known as the Urbana
State Game Farm, is located in Salem Township approximately 6 miles north of the county seat of Urbana. Dating from the late 19301s until
1963, the Urbana Area was used as the State's primary center for pheasant propagation. However, in 1963, the Division of W ildlife's pheasant rearing and stocking program was discontinued and the Game Farm was converted into a public hunting area. Its function has remained the same since that time.
Approximately one-half of the total acreage of the Urbana Area is cultivated in keeping with the State's farm game management program.
Share cropping represents approximately 95$ of this agricultural activity with the primary crops being hay, soybeans, and corn. W ild life food crop plantings make up the balance of the agricultural a c tiv ity . The remainder of the Urbana Area consists of interspersed woodland and old-field succession. The study site is located in the old-field segment and consists of an enclosed 4.05-ha (10-acre) plot of upland old-field succession. Areas located 366 m (400 yards) to the north of the study s ite having the same general type of vegetation and topography served as control areas.
Topography - The general topography of Champaign County is a product of
Wisconsin glaciation. The County, which lies w ithin the T ill Plains
Section of the Mississippi plains physiographic province, has a general 28 topography ranging from level and gently undulating pIains to extreme
■ t : o I Ly morainic h ills . The extremes of elevation are 290 m and 421 m
*(930 f t a n d'f380 ft ) (Ho Iowaychuk, 1961). The topography of the
Urbana Area ranges from nearly level to moderately and strongly sloping with maximum slopes of 12 to 18$. However, the study area and adjacent control area have a slope range of 0 to 6 %, being either level or gently sloping (Fig. 2). The study area has an elevation ranging between 346 m and 348 m (1135 f t and I 140 f t ) .
Drainage - Approximately 80 to 90$ of the study area drains in a northwesterly direction into a small interm ittent stream which in turn flows into a 0.17-ha (0.41-acre) impoundment located 92 m (100 yards) beyond the northwest corner of the study area. Because of seepage and
Hie high rate of evaporative water loss, the outflow of water below the
impoundment occurs only during the most severe spring showers.
Soils - The soils of the Champaign County region were formed on calcareous loam till and its alluvial deposits. The soil types occurring on the study area were Brookston s i l t loam, Crosby s i l t loam, Celina s i l t loam, and Miami s l i t loam (Holowaychuk, 1961). The approximate de I i.-neation of each soil type on the study area is given on the topography map depicted in Fig. 2.
Climate and Weather - According to M iller, 1969, the climate of
Champaign County is classified as continental, a climatic type characteristic of the interior regions of large land masses the size of
North America. Such a climate is characterized by wide annual and daily + Point of maximum elevation; contours depicted at 2-foot intervals Soil type boundary msl Miami silt loam bsl Brookston silty clay loam csl Crosby silt loam clsl Celina silt loam
Fig. 2. Topographic map of the study area, Urbana W ildlife Area, Champaign County, Ohio. The contours are depleted at 2-foot Interval temperature ranges and wide variations in year to year precipitation.
Based on 29 years of records taken at the Urbana weather station between
1936 and 1965, the summers in Champaign County are moderately warm and humid with the temperature occasionally exceeding 90°F. The winters are cold and cloudy with an average of 4 days of temperature in the sub zero range. The average annual p recipitation is 95.33 cm with ra in fa ll and snow composing 36.91 cm and 58.42 cm of the to ta l, respectively. A summary of the monthly temperature and precipitation data for 1969 is given in Table 2.
Although humidity, cloudiness, sunshine, and wind observations are not recorded at the Urbana weather station, Miller (1969), provided estimates of these variables based on observations taken at other
locations. He lists the mean daily changes in relative humidity as 79$ at I AM, 80$ at 7 AM, 59$ at I PM and 67$ at 7 PM. The percentage of annual sunshine as a function of cloudiness is approximately 70$ in July and 35$ in December. The prevailing annual wind direction is south with a summer mean of 8 mph and a winter mean of I I mph.
The crop growing season, when defined as the number of days between the last freezing temperature (32°F) of spring and the firs t freezing temperature of f a ll, averages 161 days (M ille r, 1969). However, this interval is highly variable. Based on data collected between 1936 and
1965, 10$ of the years had a growing season of 183 or more days, 30$ had a growing season of (70 or more days, 30$ had less than 151 days and the remaining 10$ had a growing season of less than 138 days.
Personal observations by th is investigator during 1968 and 1969 suggest that the growing season for w ild, non crop plants may be greater than 200 days in length. 31
Table 2. Summary of 1969 temperature and precipitation data, Urbana, Champaign County, Ohio3.
Average Departure of Tota 1 Departure Temperature Average Precipitation of Average Temperature Precipitation from Normal from Normal
January 23.2° F -6.5° F 3.41 inches 0.21 inches i o February 28.3 -2.8 0.96 •
March 33.3 -5.6 2.04 -1 . 16 i o Aprl 1 50.4 0.2 3.49 •
May 60.4 -0.3 3.80 -0.09
June 66.8 -3.4 6.48 2.32
July 73.4 -0.5 5.35 1 .66
August 69.2 -2.8 3.73 0.33
September 62.3 -2.8 1 .98 -0.91
October 50.8 -3.2 1.17 -1 .26
November 37.6 -3.6 4.01 -1 .46
December 26.8 -4.4 1.97 -0.39
Annua 1 Mean 48.5 -3.0 38.39 0.65
g Information taken from U.S. Weather Bureau climatological data, U.S. Dept. Commerce. 32
Study Area Vegetation - Based on soil types, topography, and existing
vegetational types, an oak-hickory association was the climax vegetation type formerly occurring on the s ite of the Urbana W ild life Area. Although
the exact time of vegetation removal from this site is not definitely
known, timber removal and agricultural a c tiv ity in the Champaign
County region was well underway by 1850 (Enoch, 1930). Between this
period and the acquisition of the site by the State in the early 1930's
as tax delinquent land, the Wildlife Area was used for agricultural
purposes. During the period that the W ild life Area was devoted to
pheasant progation, the land on which the study site is situated was
used as a natural nesting site for pheasant breeding stock. In order
to maintain the area as a nesting site, the vegetation was mowed
annually. After the cessation of the pheasant propagation program in
1963 and the in itia tio n of a farm game management program fo r purposes
of public hunting, the vegetation on the study site was allowed to revert to old-field succession. The only disturbance to the vegetation after
1963 resulted from the annual mowing of 1.8-m C6—ft ) wide grid strip s
at 73.2-m C80-yard) intervals during the late summer to fa c ilita te
rabbit trapping and population estimation operations. This practice was discontinued on the study site in 1968.
Floristic composition - The 96 species of plants collected and
identified from the study area during 1968 and 1969 are listed in Table
47 of the Appendix.
Fauna of Study Area - A Iist of the Insect species collected on the study s ite during 1968 and 1968 is given in Table 48 of the Appendix. Insect identification was provided by the Entomological Museum at the
Ohio State University. A list of the non-insect invertebrate fauna occurring on the study s ite is presented in Table 49 of the Appendix.
The la tte r lis ts are not intended to be a ll-in c lu s iv e in nature but are intended to be representative of those species encountered in the normal course of our activities on the Urbana study site. The vertebrate fauna which were e ith er collected or observed on the study site are presented in Table 50 of the Appendix.
Study Area Enclosure and Field Laboratory - During April of 1968, a 2.4-m
C8— ft ) cyclone fence was erected around the 4.05-ha study area. In order to in h ib it the egress and ingress of small mammals and reptiles following the insecticide application, a 0.6-m (2 -ft), 24 gauge sheet metal barrier was placed at the base of the fence; an additional 15.2 (6 inches) of the sheet metal barrier was buried beneath the ground to deter the passage of burrowing small mammals. An e le c tric stock fence was also installed on the exterior of the cyclone fence above the sheet metal barrier to prevent the movement of larger mammals into and out of the area. A 1.8-m (6-ft) strip of vegetation was mowed on both sides of the fence to prevent small mammals from entering or exiting the area by climbing t a ll vegatation. Mowing also prevented the e le c tric fence from being grounded by the vegetation. P articular emphasis was placed on minimizing disturbance to the study area during the installation of the fence. No vehicular t r a f f ic across the area was permitted.
A small shed located 15.2 m C50 f t ) west of the study area was renovated during the spring of 1968 and used as a field laboratory
CFig. 3). During the course of the study, th is building (which was Fig. 3. Shed located adjacent to study area which was used as a fie ld laboratory and storage f a c ility (June, 1968). 35
equipped with a re frig e ra to r-fre e ze r, a work bench and shelf space}
served as a site for the processing of field collections and the storage
of specimens and collection equipment. The shed also served as the site
for the formulation of the labeled insecticide during 1969.
i 36
Formulation and Application of Insecticide
Formulation - The formulation of the DDT was carried out on May 29, 1969, at the Urbana study site. Ninety-four grams of Cl-36 labeled DDT having an a c tiv ity level of 10.2 me was combined with 4.54 kg (10 lb) of non labeled technical grade DDT using xylene as a solvent. The Cl-36 DDT
(Amersham/Searle Corporation) was c e rtifie d to have the following
Isomeric distribution of radioactivity:
91 % p,pT-dichloro-CI-36-diphenyItrichloroethane
o,p-dichloro-CI-36-diphenyltrichloroethane
2% p-monochlorophenyl-Cl-36-phenyItrichloroethane
The nonlabeled technical grade DDT (Diamond Shamrock Chemical Company) contained 76.7 % of the Isomer p,p'-dichlorodiphenyItrichloroethane.
A fter adding 4.25 lite rs (or 1$ by weight of the fina l product) of the emulsifier Triton X-100 to the xylene solubilized DDT, the solution was divided into 20 equal portions and sprayed with a pres surized garden sprayer onto 20,22.7 kg (50 lb) batches of 18/35 mesh
RVM attapulgite clay granule carrier (Engelhard Mineral and Chemical
Corporation). In order to promote an equal distribution of the DDT on the clay granule carrier, the granules were rotated In the drum of a cement mixer during the spraying of each 22.7 kg batch of granules and fo r 5 min thereafter. A p la stic sheet b a ffle was placed over the end of the rotating drum of the cement mixer to prevent the escape of the insecticidal material; the nozzle of the sprayer was extended through a small opening in the center of the p la stic sheet. A fter mixing, the DDT impregnated granules were stored in sealed 45.5-kg (100 lb) capacity plastic garbage cans until the time of application. 37
The formulation and application of the DDT in the granular form as opposed to the more conventional spray form was necessitated by the desire to reduce the loss, of the labeled material from the 4.05-ha study site through drift. Previous studies (Hindin et al., 1966) indicated that the magnitude of insecticide loss resulting from an aerial spray operation could be as high as 50$. A loss of this magnitude in the present study would have been untenable from the standpoint of I) the possible radiation hazard to humans and livestock in adjacent areas, and 2) the impairment of the efficiency of the radioassay methodology through the reduction of the activity levels applied to the study site.
The application of the insecticide in the form of an emulsion as a drift-reducing measure was initia lly given consideration but later dismissed due to the highly phytotoxic nature of certain components of the emulsion carrier. Therefore, the compatibility of the low drift characteristics of the attapulgite clay granules and the objectivies of this study prompted the application of the insecticide in the granular form.
Application - The labeled DDT was applied to the study area on the morning of June 10, 1969, between 7:45 and 8:35 AM u tiliz in g an Ohio
National Guard Sikorsky helicopter and a "Sling King" rotary applicator
(.courtesy of Trans I and A irc ra ft) Fig. 4. The applicator was designed as a detachable unit carried beneath the helicopter fuselage by a power operated cable equipped with a magnetic latch (Fig. 5). The applicator rotor was powered by a self-contained, two-cylinder gasoline engine.
The release of the granules from the applicator hopper was determined Fig. 4. Radio-control led, gasoline powered rotary applicator used to apply insecticide to study area (June 10, 1969).
Fig. 5. Helicopter and applicator en route to study area (June 10, 1969). 39
by varying the speed of the gasoline engine; the engine, in turn, was
radio-controlled from inside the helicopter.
The applicator loading s ite was located on a small knoll 183 m
(.200 yards) north of the perimeter of the study site. After the
applicator hopper had been emptied over the study area (Fig. 6) and the
applicator returned to the loading site, the applicator was released 2 2 at ground level from the hovering helicopter onto a 37-m (44-yard )
section of plastic sheeting laid down to facilitate clean-up of any
accidental spills. The helicopter was then landed nearby until the
loading operations had been completed, a period of approximately 10 min. The applicator was again hooked-up to the helicopter using the magnetic latch as the a irc ra ft hovered overhead. All personnel d ire ctly
involved with the loading operations wore coveralls sealed at the
wrists with tape, rubber gloves and respirator, and rubber boots.
The total 454 kg (.1000 lb) of DDT-impregnated clay granules was
applied to the study area during three separate loadings of the applicator hopper. The altitude of the applicator above the study site
during each run was approximately 7.6 m (25 f t ) . A lig h t wind (2 mph) was blowing from the northeast at the time of application.’ However, 'T a ir samples taken during the course of the application (0.5 m per min or 19 ft^ per min) at a point midway between the study site and nearest
point of human habitation and analyzed by liquid scintillation counting showed no sig n ifica n t difference in dpm when compared with background
air samples taken prior to the application. No contamination of the
helicopter was observed. Although minimal contamination occurred to
the hopper of the applicator, this contamination was eliminated through Fig. 6. DDT-impregnated granules being applied to study area (June 10, 1969). 41
vacuuming and washing wi+h xylene.
An attempt was made to apply the insecticide on June 6, and on
several prior occassions. However, thunderstorms and maintenance v/ork
on the helicopter caused last minute postponements.
Application Survey - The efficiency of formulation and application and
the d is trib u tio n pattern of the DDT on the study area were determined
using specially designed samplers distributed across the study area at
regular grid intervals. The sampling devices consisted of the bottom
halves of 100-rnm diameter plastic petri-dishes; the insides of the
dishes were coaled with a thin layer of vaseline to entrap the falling
clay granules. To prevent the granules from being deflected by over
hanging vegetation, the pelri dish samplers were fastened to 30.5-cm
C l-ft) high wire-supported wood stands using rubber bands and wire
hooks CFig, 7). This height was sufficient to project the samplers
above the vegetation so that deflection of the granules did not bias
the results.
A total of 441 petri dish samplers was set out on the 4.05-ha
study site at grid intervals o*f 9.2 m (30 ft) immediately before the
application. An additional row of samplers was placed along the
outside perimeter I . 8 m (6 ft) from the fence to determine the extent
of any possible loss of the labeled material beyond the study site
boundaries. Immediately afte r the application was completed, each petri
dish was covered with its accompanying top h a lf, sealed with masking tape, labeled with the appropriate grid number, and returned to the
laboratory for analysis. The contents of each petri dish were extracted 42
Fig. 7. Vase Iine-coated petri dish granule sampling device anchored to stand prior to application CJune 10, 1969). 43
with hexane and the hexane extract counted by liquid s c in tilla tio n
spectrometry.
The contents of the petri dish samplers were prepared for liquid
scintillation counting by the following procedure:
1. The clay granules and vaseline contents of the dish were
soaked in 15 to 20 ml of glass-distilled hexane for approximately 10 min.
2. The granules and vaseline were then removed from the dish
with, the aid of wooden applicator sticks and the washing action of a
hexane-filled wash bottle.
3. The hexane was then filte re d and the f ilt r a t e concentrated
using a filte re d a ir stream to a volume of 3 ml.
4. The concentrated filt r a t e was then prepared for analysis by
liquid s c in tilla tio n spectrometry and counted for 100 min.
The efficiency of formulation and application of.the DDT was
estimated by extrapolating from the mean number of dpm of CI—36 present
in 432 petri dish samplers (nine dishes were lost from the original 441
during the application or the preparation of samples) and the area
represented by the samplers to the number of dpm present on the study
s ite . The number of dpm estimated to have been present on the study O area, [49.82 x 10 dpm or 6.75 me, was then divided by the original
activity level used in the formulation, 10.2 me, to yield the efficiency
of formulation and application of 66.18^, Based on this efficiency,
I ppm of nonlabeled DDT was equivalent to 7.56 dpm of the labeled DDT.
Therefore, the actual rate of application of non labeled DDT on the
study area was 0.74 kg/ha (0.66 lb/acre). The amount of labeled material
lost to the exterior as indicated by the 1.8-m (6-ft) strip sampled 44
at the study area perimeter was 2.07 jjc. The relatively iow efficiency
of formulation and application is not believed to be due to the loss
of labeled material to the outside of the study area during the applica
tion. Instead, the low efficiency is believed attributable to losses
occurring during the formulation phase. The primary losses probably
were associated with the spray equipment and the cement mixer used to * apply the insecticide to the clay granule ca rrie r.
The distribution of the insecticide over the study area was, in
general, uniform (Fig. 8). In order to minimize the loss of material to
the exterior of the study area, the helicopter pilot was instructed to
begin each application run from the center of the area and then to move
outward in a concentric pattern. Complete coverage of the study area
was obtained during the f ir s t run. The remaining two runs were also
In itia te d from the center and moved outward in concentric patterns,
although the course followed was not duplicated exactly. Therefore, the
resulting distribution pattern is rather complex with contiguous grid
stations in many cases showing widely differing levels of radioactivity.
This checkerboard pattern of high and low a c tiv ity levels is evident
across the study area. The radiation levels measured at each grid
station are given in Table 51 of the Appendix. 45
0
9000-20,000 dpm CI-36 1191-2646 jug DDT i i i . a 6001 - 9000 dpm CI-36 •V.V . v.v.* v.v.v,»■»■ ■ 794- 1190 jjg DDT 3001 - 6000 dpm CI-36 397 - 793 jjg DDT 0-3000 dpm CI-36 0 - 396 jjg DDT
Missing Data
2 Fig. 8. D istribution of chlorine-36 labeled DDT as indicated by 78.5 cm petri dish sampling devices (June 10, I969). 46
Liquid S c in tilla tio n Spectrometry
Instrumentation and general procedure - A Packard Tri-Carb S c in tilla tio n
Spectrometer Model 3003 equipped with Model 574 Automatic Controls and
Automatic External Standardization was used to count alt samples collected
during the course of the study. Tissues were digested in NCS solubilizer
(Amersham/Searle Corporation) in setntiI Iation-grade glass via ls. The
s c in tilla tio n solution, prepared according to the recommendations of
Hayes (1963), was composed of 5.0 g of the primary scintillator 2,5-
diphenyloxazole (PRO) and 0.3 g of the secondary scintillator 1,4-bis—2
C4-methyl-5-phenyioxazolyI)-benzene (P0P0P) in I lite r of spectrograde toluene. The temperature of the spectrometer counting chamber was -5°C.
Optimal gain settings - The optimal gain setting can be defined as that voltage amplification factor (expressed as the percent of the total voltage) which gives the maximum number of'counts per minute for a given tissue-radioisoiope combination. This setting is, therefore, a function of the intensity of color quenching produced by the solubilized tissue and the emission characteristics of the radioisotope. The optimal gain settings used in th is study (Tables 3, 4 and 5) were determined by counting representative samples of each tissue type spiked with chlorine-36.
Each spiked sample was counted at I-min intervals at progressively higher gain settings. A graph of the accumulated data was then plotted with cpm on the ordinated and increasing gain settings on the abscissa. The optimal gain fo r a given tissue type corresponded to a stable area
immediately beyond the peak of a curve of the plotted data. 47
Table 3. Liquid scintillation spectrometer optimal gain settings for mammalian tissue samples. Gain settings expressed as per cent of the to ta l machine voltage.
T i ssue Blarina Sy1vilagus Mi crotus Muste1 a So rex Peromyscus
Skeleta1 Muse 1e 1.2% 5.4% 5-052 6.7 % 7.2% 1.2%
Subcuta neous Fat 4. 1 4.7
Heart 7.0 10.7 6. 1 22.0 7.0
Spleen 4. 1 15.0 4.1 12.5 4. 1
Liver 12.0 21 .0 1 1 .0 23.5 12.0
Ki dney 5.0 9.2 7.3 13.0 __ 5.0 Adrena1 5.3 5.3 _ Lung 10.3 26.0 8.2 15.5 10.3
Brai n 3.8 4.6 4. 1 4.8 3.8
Skin and Fur 9.2 6.5 10.7 6.0 9.2 V i sceraa __ 9.0 Sub maxi 1 1 ary G1 a nd 6.5
Abdomi naI Cavity Fat 7.8
aThe to ta l viscera was used where the size of the animal was too smalf fo r the use of individual organs and tissues. 48
Table 4. Liquid scintillation spectrometer optimal gain settings for avian and re p tilia n tissue samples. Gain settings expressed as per cent of the total machine voltage.
Ti ssue Phasianus Age 1ai us Thamnoph i s
Leg Muscle 4.55! 6.85!
Breast Muscle 3.4 7.0
Heart 9.0 10.5
Gi zzard 6.5 8.2
Li ver 13.5 24.0
Lung 13.5 34.5
Ki dney 14,3 8.5
Brai n 5.5 5.5
Large Intestine 4.5
Small Intestine 8.0 ... a Viscera 9.5%
R epti1ian Ske1ta 1 Muscle 6.2
aThe to ta 1 vi scera was used where the size of the animal was too sma11 for use of i nd ividual organs and tissues.
Table 5. Liquid scintillation spectrometer optimal gain setting for herbaceous vegetation tissue samples. Gain settings expressed as per cent of the total machine voltage.
Leaves 10.831
Roots CDaucus carota) 3.7 49
High voltage setting - The high voltage setting, or that setting
representing the total voltage Input, used for the spectrometer during
the course of the study was 4.0.
Color quenching adjustment - In order to adjust for color quenching, or
the extent to which sample opacity interfered with the spectrometer
counting efficiency, a quenched series of chlorine-36 spiked samples was
prepared. An increasing gradient of quenching v/as obtained by increasing
the weight of the tissue used in each sample by 100-mg increments. The
number of samples per series varied from 10 to 20, depending upon the
tissue type. The spiked series was then counted for 100 min per sample
at a gain setting appropriate for a given tissue type; simultaneous
readings of the Automatic External Standard (AES) were made. The counting
efficiency of each sample in a series was then plotted against the
accompanying AES and a regression line calculated. By using the regression
line and the AES reading for a non-spiked sample, the counting efficiency
and degree of color quenching fo r that sample were determined.
Discriminator window setting - Based on chlorine-36 standards and back
ground samples, a discrim inator window width of 150-900 units was
found to be optimal in excluding background counts. The major portion of the background counts recorded fe ll to the le ft of the beta spectrum
between 0 and 15 units.
Samp Ie'preparation - The procedure for the preparation of liquid scintillation samples is given in the following sequence:
I) A finely divided portion of tissue was weighed in a scintilla tion vial; the weight, which varied with tissue type from 100 mg to 500 mg 50
(wet weight), was held constand for a given species tissue type.
2) Three m illilite rs of NCS solubiIizer was added to the vial
to bring about tissue digestion.
3) The capped vial was heated at 45° C for 18 hr; the contents of the vial were agitated at 5-hr Intervals to promote complete tissue
digestion.
4) After the vial was cooled to room temperature, 10 drops of
30$ (two drops per 15-min interval) were added as a bleaching agent.
5) After the H2 0 2 _generated bubbles had dissipated (5 h r), 15 ml of PPO + P0P0P scintillation solution were added to the vial.
6) Two m illiliters of Triton X-100 were added to the vial; the vial was then shaken to emulsify the solution.
7) The sample vial was then cooled inside the freezer chest of the spectrometer for 2 hr and counted for 100 min. 51
Sample Collection
Initiation of sampling - The exact time at which sample collection was to be initiated following the application was complicated by the unknown release time of the DDT from the clay granule carrier and the entrance of the insecticide into the old-field system. Although this difficulty could have been alleviated by the immediate collection of samples
following the completion of the application, the unknown consequences of intensive and unnecessary sampling on future collections of study area vertebrate species necessitated that such an arbitrary initiation time be avoided. Counterbalancing this consideration, however, was the desire to obtain the maximum amount of information concerning the movement of the insecticide immediately a fte r its entrance into the system. The eventual decision on the date of sample in itia tio n was a product of these two considerations.
The release of the DDT from the granule carrier was a function of the moisture present in the o ld -fie ld ecosystem, but the exact moisture
level at which DDT would be leached from the granule was unknown. Dew or moisture present in the detritus could have brought about th is release, to ta lly or in part. The eventual decision to begin sampling was
influenced greatly by the relatively heavy rainfall (3.71 cm or 1.46
inches) which occurred during the f i r s t week post-application.
Sampling was begun on June 16, 6 days post-application.
General sampling procedure - Samples of the flora and fauna of the study site and adjacent control areas were collected during 1969 at weekly
intervals for the firs t month post-application and thereafter at monthly 52
in+ervats until the end of the growing season in October. During 1968, the plant and animal samples were collected from the study site and control area to determine the level of background radiation; this information was later used in evaluating the data collected during 1969.
During the course of the study, all collections were made in such a way as to minimize the time interval of the collection and thereby provide bioaccumulation and translocation data for a discrete time
interval. Weekly and monthly collections were made within approximately
3 to 4 days of the starting date. At times the short collection intervals had the disadvantage of reducing sample size or preventing the collection of certain animal species. This phenomenon is primarily a function of the high species diversity and low species equitability of the old-field community. Although a re la tiv e ly large number of species occurred on the study area, only a limited number of animal species had sufficient numbers and biomass to make sample collection practical.
Where possible, four samples or subsamples of selected plants and animals were collected from both the study area and control area during each collection period. A sample size of four represents a compromise between statistical necessity and sampling practicality. Although a
larger sample size would have been more desirable from a s ta tis tic a l standpoint, the collection and processing of a larger number of samples would have been pro hib itive. Control samples were taken from an area
located 274 m to 366 m (300 to 400 yards) north of the study site; the control area was vegetatively and topographically similar to the study area. 53
Vegetation collection methods - Except in the case of the wild carrot
(Daucus carota), where both leaf and root samples were taken, the sampling of the vegetation was confined to the leaves. In order to lim it these samples and subsamples to the newest regions of biosynthesis, only the leaves from the apical regions of dicotyledonous forbs and the upper-most nodal regions of grasses were collected. During a ll collection intervals, both control and study area vegetation samples were collected within the same 12—hr period. Since no species of plant was considered to have a uniform distribution pattern on the study area, no attempt was made to c o lle ct the vegetation samples on a random basis.
However, only one subsample for a given species was collected w ithin the 2 2 same grid (335 m or 3600 f t ). Each species subsarnple was individually packaged in a plastic bag, returned to the laboratory, and frozen until the time of sample preparation.
Invertebrate collection methods - Pit-traps, or tumble-in traps, were used to collect the bulk of the Invertebrate species during the study.
The traps were constructed from clean, quart-sized aluminum oil cans sunk
Into the ground to a depth at which the top of the can was level with the ground. A mixture of baker's yeast and warm sugar water was then added as ba it using a volume equal to 1/5 to 1/4 of the volume of the can.
This b a it, when allowed to ferment for a day or two, was very a ttra ctive to slugs, millipeds, phalangids, camel crickets, greater and lesser field crickets, grasshoppers, and carabid, scarabid, and nitidulid beetles. The entrapped invertebrates were removed from the cans by pouring the contents through a tea strainer; the invertebrates 54 were placed in collection vials, returned to the laboratory, frozen, and
later sorted to species. The pit-traps, when not in use, were emptied of their contents and turned up-side down to prevent over-exploitation of the study area invertebrate fauna. Sweep-netting was also used to collect certain species of phytophagous insects, prtmarily froghoppers
(Philaneus spurmarius? and grasshoppers (Melanoplus femur-rubrum).
Insects collected by this method were killed with ethyl acetate and returned to the laboratory for sorting. Orb weaving spiders (Argiope tr ifa s c ja ta , A. aurantia, and Araneus t r t fo Ii urn) were collected
individually from th e ir webs using forceps.
Vertebrate collection methods
Small mammals - Live-trappIng was the principal method u tilize d in collecting small mammals (Blarina brevicauda, Sorex cinereus,
Microtus pennsyI vaniCus, and Peromyscus leucopus) on the study area.
Although both live-traps and snaptraps were used in collecting small mammals for control purposes, snaptraps were not used on the study area for fear of over-exploiting the small mammal populations. The use of live-traps had the advantage of allowing excess animals to be released once the desired sample size (four animals of each species) had been acquired, usually within one to two nights of trapping.
A grid system having 100 trap stations located at 18.3-m (60—ft ) intervals was employed on the study area. Two Sherman traps baited with a combination of peanut butter and oatmeal were located at each trap station. Mortality was minimized by the inspection of the traps during the early morning hours; in addition, the traps were set only during the evening and night hours to prevent animals from being captured during the 55 day and dying of heat exposure. Even with the precautions, m ortality among shrews, especially Sorex, was heavy. During the morning inspection trip s , animals considered satisfactory fo r sampling purposes were removed from the traps into plastic bags, dispatched, labeled according to grid location and date, and returned to the field laboratory and frozen.
Although live-traps were the primary method used in collecting small mammals, Sorex were also taken in the invertebrate p it-trap s described above.
Cottontail rabbits - Although a small number of rabbits existed within the confines of the 4.05-ha study plot following the fencing operations in 1968, th is number was augmented by the introduction of eight rabbits (fiv e males, three females) during April and May of 1969.
These rabbits, a ll of which wero ear-tagged before release, were captured in northern Franklin County either on the Ohio State University Farms or at a private surburban residence in the nearby city of Dublin. Control rabbits were captured on the Urbana Area. However, due to the rabbit population studies being conducted on the Urbana Area by the Division of W ildlife, the collection of control rabbits was confined to only one collection interval.
C ottontail rabbits were captured using the standard 20 x 20 x 76- cm (8 x 8 x 30-inches) wooden box trap of the type commonly used by state wildlife agencies in rabbit studies. The trap requires no bait, relying solely on curiosity to lure the rabbit into the trap. Trapped rabbits were dispatched, identified and labeled according to ear tag number, date and grid location, and returned to the field laboratory to be frozen until the time of sample preparation. 56
Mink - Shortly after the completion of the DDT application on
June 10, 1969, a group of pen-reared, wing-clipped pheasants (Phasianus
colchicus) (six cocks, six hens) were released onto the study area in
order to obtain additional bioaccumulation data. On June 12, five of
the released pheasants were discovered to have been k ille d by mink
(Mustela vison) . Between June 19 and June 23, seven mink (one adult
female and six half-grown kits) were removed from the study area by
Iive-trapping. These animals were dispatched and returned to the
laboratory for processing.
Pheasants - A fter the extensive mink predation on the pheasants
released on June 10, efforts to collect the remaining birds from that
initial release proved fruitless. Therefore, a second group of 15
wing-clipped pheasants, five adults (one cock and four hens) and 10
juveniles (five cocks and five hens), was released on June 27. Although
several attempts were made using groups of two and three hunters and a
bird dog, only three birds from th is release were recovered. The poor
returns achieved in the case of the second release were attributed to
heavy cover rather than to predation.
Red-winged blackbirds - T e rrito ria l red-winged blackbirds
(Agelaius phoeniceus) were collected with a shotgun on the study and control areas during June of 1969. The territories of all birds collected on the study area, as delineated by observations of their defensive
behavior, were within the study area boundaries.
Snakes - A small number of garter snakes (Thamnophis s ir t a lis ) was collected by hand on the study area during 1969. Although a larger
number of garter snakes was observed, the heavy matted vegetation made 57
collections d if f ic u lt and limited the number of indiyiduaIs actua11y
taken.
S ta tistica l Treatment of Data
During each collection period, a sample consisting of four sub
samples of each organism or tissue was collected from the treated area
and from the control area. The radiation levels detected in the treated
and control samples were considered representative of the radiation
levels in each population. An individual subsample from the treated area was considered to contain DDT (both chlorine-36 labeled DDT and non labeled DDT) when the number of dpm for that subsample exceeded the
level of background radiation represented by the control mean dpm plus a 99% confidence interval. Based on the known proportions of labeled and nonlabeled DDT used in the original formulation and on the formulation and application efficiency determined at the time of application, I >jg of DDT was equivalent to 7.56 dpm of chlorine-36. Since alt calculations
involved the use of I g quantities of tissues, I pg of DDT was equivalent to I ppm, or >ig/g, of DDT. The number of ppm DDT contained in each treated subsample was determine by dividing the difference between the number of dpm in the treated subsample and the control mean by 7.56. The
DDT contained in an organism or tissue during a given collection period was represented by the mean ppm DDT derived from the four subsamples.
Background Radiation Levels
Plant and animal samples were collected during 1968 from the study 58 site and adjacent areas to determine the pre-appIication background radiation levels. The background radiation levels occurring In the
1969 control samples are Included In Tables 52 through 64 of the Appendix.
Vegetation Biomass Determination
As an additional study area descriptive parameter, the net primary production by the aerial portions of the old-field herbaceous vegetation was determined during 1969 using the short-term harvest method 2 described by Odum (I960). A series of 0.25-m c llp -p lo t samples, con sisting of 12 to 16 subsamples each, was taken at six Intervals during the growing season, individual ciip-plot subsamples were located through the use of a table of random numbers and a previously established 10 x
10, 18.3-m (60-ft) interval grid system. All vegetation occurring within 2 the 0.25-m quadrat was clipped to ground level, placed In a p lastic sack, and returned to the laboratory. The living vegetation from each subsample was separated by species, oven-dried at I00°C for 24-hr, and weighed to the nearest 0.1 g.
Calorimetry
Caloric determinations were made for the muscle tissue of Blarlna brevicauda and the whole bodies of selected invertebrate species
(Melanoplus femur-rubrum, Gryllus pennsyI vantcus, Deroceras, sp.,
Hadrobunus sp., and Para.julus sp.l using a Parr adiabatic oxygen bomb calorimeter. The procedure u tiliz e d in preparing the samples fo r caloric determinations and operating the calorimeter CParr Manual, I960) are 59
given below.
1) The tissues were f i r s t dehydrated using a Vir-Tts freeze drying unit.
2) The dried tissues were then ground into a fine powder (40-mesh) using a Wiley Mi I I. The ground tissue was again dehdrated by means of the freeze drying unit to remove moisture acquired during the griding operation.
3) The ground material was then weighed in pre-weighed combustion capsules and stored in a desiccator until the caloric determinations were performed. Except in cases where the tissues were in limited supply, caloric determination for at least four subsamples of each tissue type were made. One gram of each tissue type was used fo r each subsample.
4) During the course of the caloric determination, a series of energy equivalent determination was made using 1.0 g benzoic acid p ellets.
The energy equivalent, as determined by the benzoic acid standard, rep resents the combined heat capacity of the various calorimeter components; this information is essential for accurate caloric determinations. The energy equivalent fo r the calorimeter under the conditions prevailing at the time the present caloric determinations were made (room tempera ture: 23°C, or 73.4°F) was 1358 i 1.09 caI per degree F (X 1 S.E.).
5) One ml of d is tille d F^O was placed in the bottom of the bomb to fa c ilita te the formation of ni.tric acid upon combustion of the sample.
6) The terminals of the bomb head were wired with, a 10-cm section of fuse wire; a fte r the combustion capsule containing the sample was placed in the circular terminal of the bomb head, the fuse wire was extended ju s t below the surface of the powered sample in preparation 60
for Ignition.
7) the bomb head was then placed on the bomb, sealed, and the bomb charged with 30 atmospheres of oxygen.
8) Two thousand grams (± 0.5 g) of d is tille d water were placed in the calorimeter bucket, the bomb placed in the bucket, and the terminal of the ignition unit attached to the bomb.
9) The calorimeter jacket lid was then closed and the jacket and bucket thermometers lowered; a fte r sta rtin g the motorized s tirre r, enough water was added to completely f ill the calorimeter jacket.
10) Hot water and cold water were added to the jacket as needed to bring the temperature of the latter into equilibrium with the bucket temperature.
11) After the jacket and bucket temperatures were brought to an equilibrium and verified by three temperature readings at l-min intervals, the sample was ignited.
12) Hot water was added to the jacket, to compensate fo r the rise in the bucket temperature due to heat transfer from the bomb, until the jacket and bucket thermometers again gave identical readings. The equilibrium temperature was verified by three readings made at l-min i ntervaIs.
13) After turning-off the stirrer and allowing sufficient time fo r the water to drain from the jacket, the thermometers were lifte d , and lid opened, and the bucket and bomb removed.
14) The bomb was then removed from the bucket, dried, placed in a bench clamp, and the pressure released from the inside of the bomb. 61
15) The combustion capsule and the ash were removed from the bomb head and the bomb interior washed with distilled water; the wash water was collected in a beaker, diluted with 100 ml of distilled water, and titra te d with a 0.0725 N solution of sodium carbonate following the addition of four drops of methyl orange indicator. The m illiliters of titration solution used are indicative of the calories utilized In the formation of nitric acid.
16) The fuse wire remaining after ignition was removed and measured to determine the length of wire and the number of calories consumed in the combustion.
17) The following equation was used in computing the gross heat of combustion, Hg, in calories per gram:
Hg = tW - 6| " e 2
m
where
t = the net corrected rise in temperature
W = energy equivalent of calorimeter
m = mass of sample
ej= correction in calories for heat of formation of nitric acid
e£= correction in calories for heat of combustion of fuse w i re
18) The live weight caloric content of each tissue type was derived by correcting the ca loric values determined on a dry weight basis for the percent of water lost in drying. The percent water loss was calculated for the above tissues through a series of weight 62 determinations following dehydration by freeze drying.
A ir Samp Ii ng
An attempt was made to measure the loss of DDT to the atmosphere by means of vaporization and codistillation with water under the natural conditions existing in the o ld -fie ld community. DDT has been shown to move from a point of application to the surrounding atmosphere by both mechanisms under laboratory conditions (Acree et a l., 1963; Lloyd-
Jones, 1971). However, no information concerning the action of these mechanisms of insecticide dispersal under natural conditions is available.
The a ir sampling apparatus u tiliz e d was a portable device designed to sample large volumes of air for pesticides automatically over a 24-hr period (Fig. 9). This same apparatus is being used by the
Pesticide Surveillance Unit of the Public Health Service in a nationwide survey of air-borne pesticides. Basically, the a ir sampler was composed of a tra in of samplers consisting of a coarse fiberglass f i l t e r , a
Greenburg-Smith impinger containing hexylene glycol as a collecting liquid and an alumina-filled absorption tube. As the air is moved through the sampling train by a vacuum pump, pesticides in the air are removed in the hexylene glycol and on the alumina. The coarse fiberglass filte r intercepts particulate matter at a point near the air intake.
The duration of the a ir flow through the sampling tra in is regulated by a timing apparatus; an air flow rate meter regulates the volume of air sampled by each sampling tra in . Each tra in was operated for a 12-hr period. A fter 24 hr of sampling, the hexylene glycol, alumina and 63
*
Fig. 9. A ir sampling device in place on study area (August, 1969). 64 fiberglass f i l t e r were removed and a new f i l t e r and supply of reagents substituted fo r continued sampling. The components were removed to the
laboratory, extracted with hexane, and assayed by means of liquid scintillation spectrometry.
The a ir sampler was operated at a point d ire c tly in the middle of the Urbana study area; the intake pipe of the sampling trains was
1.7 m (5.5 ft) above the ground. A power line to supply the 110 volt power requirement of the sampler was run from the fie ld laboratory.
Control samples were taken in the c ity of Urbana with a sampler
identical to the one used on the study area. During 1969, the air samplers used at both sites were supplied courtesy of the Ohio Department of Health and the U.S. Public Health Service. Although the collection of control samples in an urban setting rather than a rural setting was not completely desirable, the City of Urbana site was chosen for control sampling to complement the sampling program of the Ohio Department of
HeaIth.
Air Sample Preparation - The hexylene glycol and the a Iumina-fiberg I ass f i l t e r sampling tra in components were extracted fo r DDT with hexane in separate steps of the sample preparation procedure. However, the extracts of both component groups were eventually combined in the final preparation of the sample for liquid scintillation counting. The following procedure was used in the preparation of air samples for analysis: ,
I) The fiberglass filters and the alumina, including the glass- wool plugs retaining the alumina in the absorption tube, from the two
12-h.r sampling tra in s were pooled and placed in a 45-mm x 600-mm 65 chromatography column. Two 150—mI portions of hexane were then passed through the column and collected in a beaker.
2) Two 100-ml portions of d is tille d water were added to the column to force the last one-third of the hexane off the alumina.
3) The resulting mixture of water and hexane extract was separated in a I-I iter separatory funnel.
4) The water remaining in the hexane extract was then removed by passing the extract through an 8-inch column of Na 2 S0 ^ granules contained In a 25-mm x 400-mm chromatography column; the column of
Na2 S0 ^ was then washed with 50 ml of hexane.
Hexylene glycol extraction
1) The two 100-ml portions of hexylene glycol contained in the two impingers were pooled and placed in a I-I ite r separatory funnel.
The containers used in transporting the hexylene glycol samples from the field were each washed with 100 ml of distilled water and the water added to the pooled hexylene glycol.
2) Two-hundred m illilit e r s of d is tille d water were added to the hexylene glycol contained in the separatory funnel.
3) Two 100-ml portions of hexane were then added to the hexylene giycol-water solution. After each portion of hexane was added, the separatory funnel was shaken for I min and allowed to stand for I hr.
4) The hexane was separated from the hexylene glycol and water using the separatory funnel.
5) The hexane extract was then dried by passage through Na2S0^ granules contained in a 25-mm x 400-mm chromatography column.
6) The alumina-fi Iter and hexylene glycol extracts were combined 66
and evaporated in a filte re d a ir stream to a volume of 3 ml. The 3 ml of hexane were then placed in a s c in tilla tio n vial and prepared for
liquid scintillation counting.
Study Pond Monitoring Procedure
Samples of the biota, water and bottom soil were collected from
the 0.17-ha pond receiving drainage from the study area to monitor the
possible loss of DDT from the study area through run-off.
Extraction of Bottom Material - To determine the presence of DDT deposits
in the study pond bottom material, samples of the most recently deposited
bottom so il (approximately 3 cm in depth) were taken at 31, 65, and 92
days post-application. Control samples were taken from a pond having
sim ila r size, volume, and depth characteristics located 0.25 mile
south of the study pond. The following procedure was used to extract
possible DDT deposits from the soil:
1) After returning the samples to the laboratory, each soil
sample was placed in a clean porcelain pan, covered with several layers
of cheese cloth, and allowed to air dry.
2) When the soil was completely dry, it was finely ground in a
good grinder.
3) Each sample was then divided into four, 100-g subsamples;
each subsarnple was placed in a 0.95-1 ite r ja r ( l- q t Mason ja r) with
200 ml of technical grade hexane and shaken fo r 30 min in a commercial
paint shaker.
4) The hexane was then decanted; a second 200-ml portion of 67
hexane was added to the subsample and shaken for an additional 30 min.
5) The second portion of hexane was decanted from the subsample, combined with the firs t 200-ml portion of hexane extract, and filtered; the remaining soil was filte re d and washed with 100 ml of hexane.
6) The combined hexane filtra te s were then concentrated to a 3-ml volume, placed in a s c in tilla tio n v ia l, and prepared for liquid scintillation counting by the method described above.
Water Analysis - Water samples were collected from the study pond at appropriate intervals during the course of the summer to monitor for
DDT which might have been carried into the pond from the study area in run-off. Care was taken during each sample collection to take only water near the surface (approximately 8 cm in depth) and to avoid the creation of turbidity at the site of collection. In addition, a number of sites along the pond perimeter were sampled during each collection period to insure that the sample was representative. During sample preparation, each sample was divided into two portions, one to be filtered and analyzed for DDT which might be associated with the particulate matter and the other to be extracted with hexane for DDT that might be associated with both the particulate matter and the water. The following procedure was used in the preparation of the water samples:
Particulate matter
1) A 50-ml subsample of water was filte re d through a 25-ml,
0.45- > j millipore filte r using an aspirator.
2) The filte r and the deposited particulate matter were then pIaced i n a 20-ml sci n tiI I at ion vial and so Iub i Ii zed usi ng 3 ml of NCS 68 solub iI i zer.
3) Following the solubilization of the filter and the deposit of particulate matter, the subsarnple was then prepared fo r liquid scintillation coundint in a manner described earlier for plant and animal tissues. An optimal gain setting of 3.1$ was used in counting the particulate subsamples.
Hexane extraction
1) Seven-hundred and f i f t y ml of water were placed in a I-I ite r separatory funnel. A fter adding 100 ml of hexane, the separatory funnel was shaken fo r I min.
2) After allowing the hexane-water mixture to stand for I hr following shaking, the water phase was drained into a I-I ite r beaker.
3) The water phase was then returned to the separatory funnel and the hexane extraction procedure was repeated.
4) The hexane from the f i r s t and second extractions was then dried by passage through t^SO^ granules. After the hexane extract had been dried, the NagSO^ granules were washed with 100 ml of hexane and the wash combined with the extract.
5) The dried hexane extract was concentrated by a filtered air stream to a volume of 3 ml, placed in a s c in tilla tio n vial and prepared for liquid scintillation counting in the previously described manner.
An optimal gain setting of 2.1$ was used in counting the hexane- extracted water samples. 69
Gas Chromatography
Four specimens each of Blari na brevi cauda and Sorex ci nereus collected in 1968 from the study area were analyzed by gas chromato graphy to determine the pre-application levels of DDT present in the old-field ecosystem. The eastern half of the Wildlife Area on which the study area is located has no history of insecticide use. However, insecticides are commonly used for agricultural purposes on the remainder of the Wildlife Area and in the surrounding countryside. The analyses were performed on a Barber Colman Chromatograph Series
5000 equipped with an electron capture tritiu m detector and a 4 - ft glass column. The column was packed with a 1.7$ 0V-I7 and 1.95$ QF-I liquid phase on a 100/120 mesh Gas-Chrom Q support. The following operational conditions were employed: injector temperature, 210° C; column temperature, 200° C; detector temperature, 210° C; sensitivity setting,
300X; voltage setting, 30 v; nitrogen gas flow rate, 120 ml/mtn.
Sample preparation
I) After the total body weight of the shrew was recorded, the ani.mal was skinned and the carcass weight recorded.
21 The carcass was dried in a V ir-Tis freeze drying un it, ground into a powder, and extracted for 8 hr in a Soxhlet apparatus with 240 ml of ethyl ether and petroleum ether (170 ml of petroleum ether and
70 ml of ethyl ether).
3) The ether extract was then concentrated to a 100 ml volume in a flash evaporator.
4) As a clean-up procedure, 25-ml of the extract were passed through 70 a 25-mm x 400-mm chromatography column containing 15.2 cm of activated f l o r is i l and 5.0 cm of granular anhydrous Na2S0^.
5) Two separate elutions of the column were made using two 200-ml portions of ethyl ether and petroleum ether (5$ and 15$ ethyl ether); the
5$ and 15$ eluates were kept separate. After each 200-ml portion of ether had been passed through the column, the column was washed with
50 ml of 5$ and 15$ ether.
6) The 5$ eluate was passed through a second f lo r is il column; the column then was washed with 50 ml of 5$ ethyl ether.
7) The second column was eluted with a 200-ml portion of 15$ ethyl ether.
8) As an additional clean-up procedure, the two 15$ eluates were passed through a 25-mm x 400-mm chromatography column containing
10 g of Ce I i te-MgO (1:1).
9) The 5$ and 15$ eluates and a series of DDT and DDT metabolite standards were then spotted on a thin -layer chromatography plate; a
98$ n-heptane and 2$ acetone solvent system was used to separate the metabolites on the thin-layer plate. Rhodamine-B dye was used to visualize the extracted metabolites and standards.
10) The extracted metabolites and the standards were then eluted from the thin-layer plate with hexane and injected into the gas chromatograph.
11) An efficiency determination was made using the above extraction and clean-up methods and shrew tissue spiked with known quantities of
DDT and DDT metabolites. RESULTS
Vegetation Residue Data
Background radiation levels - During 1968, variations in the levels of
background radiation were detected between paired samples of vegetation
Cleaves) from the control and study areas (Table 52). In a ll cases where variation was evident (10 of 45 paired samples taken throughout the growing season), the study area radiation levels (X dpm) exceeded
the control radiation levels (X dpm + 99^ confidence interval).
Variation was not detected in a ll species nor in a ll collections of any one species. The plant species displaying variation, the collection
period, and the magnitude of difference between the radiation levels of the control and the study area samples are given in Table 6. Also given in Table 6 are the theoretical levels of DDT which would be
present if the differences in background levels were attributable to
the presence of chlorine-36 labeled DDT.
Possible causes for the differences in radiation levels are I)
localized variation in the levels of naturally-occurring radiation and
radiation originating from fa llo u t, and 2) excessive quenching (color or chemical quenching) in the liquid s c in tilla tio n samples resulting
from variations in pigmentation (chlorophyll) and in the water content of the vegetation sampled. The likelihood that the observed variations can be attributed to localized variations in natural and/or fallout
radiation seems minimal due to the small area from which the sample groups were taken. The radiation levels from these sources would be
71 72
Table 6. Summary of the variations in background radiation levels occurring between samples of control and study area vegetation (leaves) during 1968.
Species Col lection Difference Between Theoretical DDT Date Study Area and Con Residue Levels^ tro l Area Mean Radiation Levels3 (dpm) (ppm DDT)
DactyIi s glomerata 7/9/68 1.24 0. 16
Agropyron repens 8/7/68 I .49 0.20
AchjI lea mi IlefoIiurn 8/7/68 3.40 0.45
9/10/68 1.76 0.23
10/13/68 0.30 0.04
Sol jdago .juncea 9/10/68 1.30 0. 17
Daucus carota 8/7/68 4.1 I 0.54
10/13/68 I .20 0. 16
Erigeron ph iIadeIph i cu; 8/7/68 5.88 0.79
Vernon i a noveboracens i s 9/10/68 I I .05 I .46
difference obtained by subtracting the control X dpm+99/2 confidence interval from the study area X dpm.
d n e ppm DDT equivalent to 7.56 dpm of chlorine-36. 73 expected to be homogeneous over such a small area. Excessive quenching appears to be the most probable cause fo r the observed variations. All study area vegetation samples displaying variation were composed of two or more subsamples characterized by higher than normal levels of quenching. When these subsamples were adjusted to compensate fo r the quench-induced reduction in counting e fficie ncy, an in fla tio n of the radiation levels for those subsamples and the sample mean resulted.
No definite reason can be given for the higher levels of quenching occurring among the study area plant samples other than the possible increase in pigmentation and water content. Fluctuations in the latter two factors could have resulted from variations in the vigor of the plants from which individual subsamples were collected or from variations in the time of day during which the samples were collected.
Vegetation DOT residue data - If assumptions are made that I) only those species displaying variation during 1968 would display similar variations during 1969 and 2) the levels of variation observed in 1968 were the maximum levels likely to occur in 1969, the statistically significant levels of radiation detected in most of the 1969 study area vegetation samples are considered valid measures of radiation attributable to the chlorine-36 labeled DDT. The radiation levels detected in the leaves of 10 of the 13 plant species analyzed exceeded the control background radiation levels (Table 7). The 10 species i ncIuded Agropyron, Poa, Achi I lea, So Ii dago, Ci rsi urn, Daucus, Pasti naca,
Aster, Vernonia and Erigeron. No DDT residues were detected in DactyIis,
Phleum, and PIantago. DDT was also detected in the roots of Daucus
(Table 8). 74
Table 7, DDT residue levels in the leaves of Study Area vegetation, 1969.
Species and Days X ppm DDT Number of Range in ppm Post-App1i cation ± S.E. Subsamples DDT
Dactyl is glomerata
6 Days NDa 4
16 ND 4
23 ND 4
29 ND 3
62 ND 4
92. ND 4
122 ND 4
Agropyron repens
6 Days 2.11 t 1.25 4 0.00 - 4.91
16 ND 4
23 ND 4
29 0.29 + 0.19 4 0.00 - 0.78
62 NCPb
92 NCP
122 NCP
Poa spp.
6 Days ND 4
16 ND 4
23 ND 4
29 ND 4
62 1 .66 ± 0.42 4 0.00 - 3.32 .75
Table 7. (Continued). ______
Species and Days X ppm DDT Number of Range in ppm Post-Application t.S.E, Subsamples DDT
Poa spp.
92 Days 1.86 t I .09 4 0.00 - 4.18
122 ND 4
Phleum pratense
6 Days ND 4
16 ND 4
23 ND 4
29 ND 4
62 NCP
92 NCP
122 NCP
Achi I lea mi Ilefoliurn
6 Days 1.37+0.60 4 0.00-2.38
16 ND 4
23 I .23 t 0.85 4 0.00 - 3.59
29 ND 4
62 3.30 ± 0.70 4 2.35 - 5.18
92 2.31 ± 0.91 4 0.00 - 4.44
122 3.46 + I .45 4 0.00 - 6.06
So 1i dago juncea
6 Days ND 4
16 0.14 ± 0.20 4 0.00 - 0.55
23 ND 4 76
Table 7. (Continued). ______
Species and Days X ppm DDT Number of Range in ppm Post-Application t S.E. Subsamples DDT
So Ii dago juncea
29 Days ND 4
62 ND 4
92 ND 4
122 ND 4
Ci rslum arvense
6 Days ND 4
16 ND 4
23 0.01 ± 0.02 4 0.00 - 0.05
29 0.40 ±0.41 4 0.00 - I .61
62 0.56 1 0.33 4 0.00 - I .44
92 ND 4
122 NSPC
Daucus carota
6 Days ND 4
16 ND 4
23 ND 4
29 ND 4
62 15.94 1 I .96 4 I I .04 - 19.47
92 4.22 t 0.59 4 2.97 - 5.77
122 ND 4
Pasti naca sati va
6 Days ND 4 77
Table 7. (Continued).
Species and Days X ppm DDT Number of Range in ppm Post-App1i cation ± S.E. Subsamples DDT
Pastinaca sativa
16 Days ND 4
23 0.96 ± 0.96 4 0.00 - 3.83
29 ND 4
62 0.93 ± 0.93 4 0.00 - 3.72
92 ND 4
122 ND 4
Aster ericoides
6 Days NCP
16 ND 4
23 4.42 t 4.42 4 0.00 - 17.69
29 ND 4
62 0.38 ± 0.22 4 0.00 - 0.81
92 7.79 ± 1.92 4 3.76 - 12.04
122 ND 4
Vernon i a noveboracensIs
6 Days NCP
16 NCP
23 NCP
29 NCP
62 NCP
92 0.66 t 0.44 4 0.00 - 1.87
122 ND 4 78
Table 7. (Continued).
Species and Days X ppm DDT Number of Range i n ppm Post-App1i cation ± S.E. Subsamples DDT
Eri geron ph i 1adelph icus
6 Days NCP
16 NCP
23 ND 4
29 0.36 ± 0.36 4 0.00 - 1.07
62 1.43 ± 1.13 4 0.00 - 4.74
92 NCP
122 NCP
Plantago lanceolata
122 Days ND 4
a ND Not detected.
b NCP No sample collected.
c NSP No sample prepared. 79
Table 8. DDT residue levels in the roots of the Wild Carrot (Daucus carota) , Urbana Study Area, 1969.
Days Post- X ppm DDT Number of Range in ppm App 1i cation + S.E. Subsamples DDT
6 Days NSPa
16 NSP
23 0.10 ± 0.06 4 0.00 - 0.25
29 NSP
62 1.70 ± 0.93 4 0.00 - 4.40
92 NDb
122 ND 4
g NSP No sample prepared.
^ND Not detected.
Among the above species, AchiI lea, Daucus, Agropyron, Erigeron,
and Vernonia displayed variations in radiation levels during 1968. It
is assumed that the possible variations in background radiation levels
during 1969 were no greater than those levels measured in 1968, the
radiation levels in Ach iI lea and Daucus were higher than the background
radiation levels and must be attributed to the chlorine-36 labeled DDT.
The same view would be true fo r Agropyron and Erigeron with the
exception of the residue levels detected in both species at 29 days.
The latter residue levels may be attributed to variations In background
radiation and not to the presence of labeled DDT. The low residue
levels given for Soli dago and Vernon i a are questionable and could be 80
attributed to background radiation. The residue levels listed for the
remaining species in Table 7 are considered valid since no variation
in background radiation was noted among these species in 1968.
Invertebrate Residue Data
In general, the o ld -fie ld study area had a rather high diversity of invertebrates. However, few species were represented in sufficient
numbers and biomass to be compatible with the methods of sample preparation. In the preparation of most invertebrate species for
liquid scintillation counting, a tissue weight of 500 mg per subsample was used. In addition, a sample size of four subsamples per co llectio n, or 2.0 g, was necessary. An exception to this desired subsample weight was made in the case of small species of insects Cformicids and spittlebugs) where the small body size and the large number of
individuals used per subsample tended to increase the amount of c h itin present. The increase in chitin, in turn, increased the degree of quenching beyond a desirable lim it. To overcome this problem, a weight of 250 mg was substituted. Nevertheless, even with small species, I .0 g of tissue per species was necessary at each collection interval. Therefore, due to the large numbers of individuals and biomass necessary, only a few species of i nvertebrates v/ere plentiful enough to supply the sampling demands of the study throughout the growing season.
Coupled with the sampling problem created by the normal abundance of the o ld -fie ld invertebrate species, the phenology of 81 these species also tended to lim it the number of species sampled during a given collection interval. During the first month, only a few species such as the spittfebug (Philaenus spurnarius) and the nitidulid beetles
(GlischrochiI us spp.) had reached a point in their life cycles as to be abundant enough to sample. The bulk of the invertebrates sampled, however, possessed life cycles which favored an abundance in number and body size coinciding with the late summer and early fall months. The grasshoppers, crickets, millipeds, slugs, phalangids and orb weaver spiders a ll reached th e ir peak in abundance at th is time. The residue data for the invertebrate species collected from the study area during
1969 are given in Table 9.
Spittlebug - Collections were made of the spittlebug (Philaenus spumarius) at 9, 13, 21, and 62 days post-application. Beyond 62 days post-application, or after early August, this species declined in abun dance, an abundance correlated with the peak period of growth of the major species of grasses CPhleum pratense, Agropyron repens, and
Dactyl is glomerata). DDT was detected only in the 21 day collection
CO.003 ppm).
Nitidulid Beetles - Two closely related species of nitidulid beetles
CGIi schroch jI us fasciatus and quadri s f gnatus) were collected at
9, 21, and 28 days post-application. DDT was detected only in the
28 day collection. These species of beetles are classified primarily as sap feeders (Dill ion and Dill ion, 1961). 82
Formicids - Because of small body size, the large number of individuals necessary fo r sample preparation, and the likelihood of several species being present in a sample,col lections of these insects were combined and referred to by family name rather than by species names. DDT residues CO.98 ppm) were detected at 9 days post-application, the only collection made during the season.
Phalangids - The pholangid Hadrobunus sp. contained DDT residues at 21 days C l.71 ppm), 28 days (0.87 ppm), 62 days (0.54 ppm) and 91 days post-application (I. I I ppm). The absence of collections of this invertebrate at 9 and 13 days can be attributed to the life cycle of the species and to a natural low abundance. The absence of a phalangid collection at 126 days can be attributed to a series of killing frosts.
Gastropod - The highest residue levels occurring among the invertebrate species analyzed were detected in the slug Deroceras sp. at 91 days post-application (20.67 ppm). The residue levels detected at 21, 62, and 121 days were 20.16, 16.38, and 18.35 ppm, respectively. The slug population was low during the first month following the application.
Only enough material was collected during the 21 day collection to permit the preparation of one subsample. No slugs were collected during the 9, 13, and 28 day collections. However, the slug population increased in August, September, and October so the fu ll sample size of four could be obtained from the 62, 91, and 121 day collections.
Based on the work of Getz (1959) and Chichester and Getz (1969), the slug collected and analyzed in the present study was most like ly either D. laeve, a native species, or D_. ret icu Iatum, a European species 83
now widely distributed in North America. Both species are common to
old-field communities. The species D_. reti cu I atum (- Agriol imax
re tic u Ia tu s ) was observed by Hunter (1968a) in northern England to
produce two generations per year, a spring generation and a fa ll gen
eration. He found few adult slugs in June, a time midway between the
two generations; the tendency for slugs and certain other molluscs to
die shortly after breeding was given as an explanation for this
phenomenon. Therefore, the scarcity of slugs in the June and July
samples on the Urbana study site may be attributed, at least in part,
to the natural timing of lif e cycle events in the genus Deroceras.
Diplopod - DDT was detected in the milliped Parajulus sp. during all
three of the seven collection periods when sufficient material was
available for sample preparation. A residue of 7.53 ppm was found in
the two subsamples collected at 9 days post-application. The residue
levels present in the 91 and 121 day collections were 2.06 and 2.29
ppm, respectively. No m illipeds were collected between mid-June and
August in quantities adequate for sample preparation. No definite explanation is available for the low abundance of the millipeds during th is period. The low abundance, however, cannot be attributed to the
insecticide application entirely since the abundance of millipeds on the control area was also low.
Orthopterans - All four species of orthopterans analyzed contained residues of DDT during at least one collection period. The red-legged grasshopper (MeIanopIus-femus rubrum), the lesser fie ld cricket
(Nemob i us a I Iard i ) and the greater fie ld cricket (GryI I us pennsyI van i cus) 84
reached th e ir peak in abundance during the period from August to October.
Although never too abundant at anytime, the camel cricket (Ceuthoph iI us
d i vergene) was taken in limited numbers from July through August. The
highest residue level was detected in the lesser field cricket at 62 days (2.21 ppm). The maximum residue levels in the greater fie ld cricket, red-legged grasshopper, and camel cricket also occurred at
62 days (0.81 ppm, 0.25 ppm, and 0.3! ppm, respectively).
Orb Weaver Spiders - The black and yellow garden spider (Argiope aurantia), the banded garden spider (Argiope trifasciata) and the shamrock spider (Araneus trifo liu m ), all members of the family
Araneidae or Orb Weavers, reached a peak in size and abundance during early September and then waned in abundance toward the end of September and early October, Apparently the phenology of this group is such that the peak in development and maturity is synchronized with the peak in abundance of certain o ld -fie ld insect prey species. Banded garden spiders were inadvertently collected in August while sweep-netting for insects; individual size was so small and the number of individuals so
limited that no samples were prepared for residue analysis. 3y
September, however, body size was such that individual spiders collected separately by means of forceps were usually of sufficient size as to make-up one subsample.
Niche segregation between members of the genus Argiope, of which
A_. t r i fasciata was the most common, and the genus Araneus appears to be attributed in part to the height of the web and the stratum of vegetation utilized in construction of the web. The web of the 85
Table 9. DDT residue levels in the invertebrate species collected on the Urbana Study Area, 1969.
Species and Days X ppm DDT Number of Range in ppm Post-Application ± S.E, Subsamples DDT
Deroceras sp.
9 Days NSCa
13 NSC
21 20.16 I
28 NSC
62 16.38 t 2.91 4 I I .49 - 23.96
91 20.67 ± 0.19 4 20.28 - 21.14
121 18.35 ± 1.49 4 14.95 - 22.22
Nernob i us a I I ard i
9 Days NSC
13 NSC
21 NSC
28 NSC
62 2.21 ± 0.25 4 1.94 - 2.94
91 0.71 ±0.11 4 0.43 - 0.91
121 2.07 ± 0.43 4 I .05 - 2.93
Hadrobunus sp.
9 Days NSC
13 NSC
21 I .71 t 0.38 2 I .33 - 2.09
28 0.87 ± 0 .1 4 4 0.57 - I .20
62 0.54 ± 0.29 4 0.05 - 1.35 86
Table 9. (Continued)
Species and Days X pprn DDT Number of Range i n ppm Post-AppIi cati on ± S.E. Subsamples DDT
Hadrobunus sp.
91 Days l.lll 0.34 0.26 - 1.85
121 NSC
GryI I us ponnsyI van i cus
9 Days NSC
13 NSC
21 NSC
28 NSC
62 0.81 t 0.12 4 0.53 - 1.12
91 NDb 4
121 0.66 ± 0.26 4 0.26 - 1.3!
ParajuI us sp.
9 Days 7.53 ± 0.28 7.24 - 7.81
13 NSC
21 NSC
28 NSC
62 NSC
91 2.06 ± 0.37 4 I .39 - 2.92
121 2.29 ± 0.20 2 2.09 - 2.49
Araneus t r i folium
9 Days NSC
13 NSC
21 NSC 87
Table 9. (Continued).
Species and Days X ppm DDT Number of Range in ppm Post-Application i S.E. Subsamples DDT
Araneus t r i fo li um
28 Days NSC
62 NSC
91 ND
121 ND
\rgiope trifasciata
9 Days NSC
13 NSC
21 NSC
28 NSC
62 NSC
91 ND
21 NSC
^rgiope aurantia
9 Days NSC
13 NSC
21 NSC
28 NSC
62 NSC
91 ND
21 NSC
Me IanopI us femur-rubrum
9 Days NSC 88
Table 9. (Continued).
Species and Days X ppm DDT Number of Range in ppr Post-App1i cation ± S.E. Subsamp1es DDT
Me lanop 1 us femur-rub rum
13 Days NSC
21 NSC
28 NSC
62 0.25 ± 0.11 4 0.00 - 0.48
91 0.04 + 0.03 4 0.00 - 0.13
121 0.13 ± 0.11 4 0.00 - 0.45
Philaenus spumarius
9 Days ND 4
13 ND 4
21 0.003 ± 0.003 4 0.00 - 0.01
28 NSC
62 ND 4
91 NSC
121 NSC
GlIschrochilus spp.
9 Days ND 1
13 NSC
21 ND 3
28 0.15 t 0.09 4 0.00 - 2.33
62 NSC
91 NSC
121 NSC 89
Table 9. (Continued).
Species and Days X ppm DDT Number of Range in ppm Post-App1i cati on ± S.E. Subsamp1es DDT
Ceuthophilus divergene
9 Days NSC
13 NSC
21 NSC
28 ND 3
62 0.31 ± 0.01 2 2.25 - 2.43
91 NSC
121 NSC
Form!ci dae
9 Days 0.98 1 0.10 3 0.88 -1 .1 9
13 NSC
21 NSC
28 NSC
62 NSC
91 NSC
121 NSC
a NSC No sample collected due to phenology or low abundance.
b ND Not detected. 90 shamrock spider was situated among the ta lle r plants, usually wild parsnip (Pastinaca sativa ), and in open areas with l i t t l e or no obstruction by other plants. The members of the genus Arqjope, in contrast, tended to build th e ir webs closer to the ground w ithin the grass and low forb stratum. Therefore, the type of insect prey species taken by members of these two genera is apparently influenced by the web-building behavior.
No DDT residues were detected in either of the three species of orb weaver spiders at 91 and 121 days post-application.
Vertebrate Residue Data
S hort-tailed shrew - The residue levels of DDT (expressed as micrograms of DDT per gram of tissue, or ppm DDT) for selected tissues of the short-tailed shrew (Blarina brevicauda) are given in Table 10. The total body burdens of DDT (expressed as micrograms of DDT) and the total body residue levels of DDT (ppm DDT) are given in Table II. The number of micrograms of DDT present in each tissue type, or the tissue burden, is given in Table 12. The tissue DDT burden data were obtained by prorating the residue levels for each tissue type for the actual tissue weight. These tissue weights were based on the percent weight of each tissue type relative to a mean body weight of 15.9 g. The percent weight of each tissue type and the actual tissue weight were based on the tissue weights of dissected adult animals (n=4). The mean body weight was derived from the weights of all short-tailed shrews collected and analyzed from the study area in 1969 (n=26). The percent 91
age of the mean body weight and the actual weights of individual tissues
are given in Table 13. The total body residue levels (ppm) were obtain ed by summing individual tissue burdens and dividing total body burden by the mean body weight of 15.9 g.
The highest residue levels detected during the course of the
study for individual organisms were encountered in the short-tailed shrew, a fact consistent with the known accumulation characteristics of DDT and the trophic position of this species. DDT was detected in most all the tissues of the short-tailed shrew during ahl collection periods.
Although a general increasing time-related trend is evident in the residue levels of most of the tissues analyzed, fluctuations in residue
levels occurred among collection intervals as well as between individuals within collections. Such fluctuations are believed to reflect varia tions in the composition of each collection due to unavoidable differences in sex, age, and exposure time. The small size of the shrew population on the study area made collections and analyses based solely on any of the above variables impossible. Fluctuations in residue levels either between collections or between individuals within collections could also have resulted from differences in diet. Such differences could have resulted from variations in the location of
Individual home ranges on the study area and from variations in the composition and relative abundance of different prey species.
Maximum residue levels were detected in the skeletal muscle
(31.12 ppm), liv e r (64.95 ppm)., and lung (.12.43 ppm) at 60 day post- application. Maximum residue levels in the kidneys (22.20 ppm), brain
(10.05 ppm), heart (21.49 ppm) and skin and fur (29.53 ppm) occurred at 92
126 days post-application. A significant positive relationship
(P < 0.05) occurred between time and the residue levels in the kidneys
(t = 2.549; df = 5). The increasing trend in residue levels in the
kidneys over the course of the growing season is probably associated
with an increased rate of DDT elimination from the organism via the
kidneys in the form of the soluble DDT metabolite, DDA. DDT was
detected in the lungs and in the heart during a ll collection periods.
Residues in these two organs suggest a respiratory route of entrance,
although DDT derived from ingested material and associated with the
blood may also have been responsible for these residues. A significant
positive linear relationship (P < 0.05) occurred between time and the
residue levels in the lung (t = 2.196; df = 5) and in the live r (t =
2.320; df = 5). Residue levels in the remaining tissue types were not
significantly related with time. The total body residue levels ranged
from a low of 2.20 ppm at 17 days post-application to a maximum level of 13.70 ppm at 126 days (Table 10). A significant positive linear
relationship (.P < 0.05) occurred between time and the total body residue
levels ( t = 2.819; df = 5).
The total body residue levels presented here are probably some what low because subcutaneous fa t was excluded from the tissues analyzed. However, this tissue was never present in sufficient amounts to permit adequate sample preparation and analysis. A few samples were prepared, however, with the limited tissue which was available to v e rify the presence of DDT. One such sample (0.3648 g) prepared from an animal collected at 8 days produced 1396.02 counts per minute (cpm).
A control sample of sim ilar weight (0.3520 g) produced 22.45 cpm. If 93
Table 10. DDT residue levels in the tissues of the short-tailed shrew (Blarina brevicauda), Urbana Study Area, 1969.
Time and X ppm DDT Number of Range in ppm Exposure Time ± S.E. Subsamples DDT
Skeleta1 Muse 1e
8 Days 10.16 + 10.19 2 0.00-20.32
17 6.98 ± 3.12 4 0.67-14.95
21 12.86 + 6.91 4 0.48-28.45
29 14.96 ± 9.68 4 0.40-42.44
60 31.12+ 15.49 4 3.07-73.54
91 15.79 + 5.61 4 5.86-31.84
126 24.93 t 4.34 4 19.61-37.80
Heart
8 Days 17.50 1 17.62 2 0.00-35.15
17 4.43 + 2.83 4 0,02-11.85
21 13.06 ± 8.42 4 0.00-35.29
29 7.27 ± 6.98 4 0.00-28.19
60 21.43 ± 7,91 3 5.63-29.81
91 13.45 ± 7.27 4 0.42-32.24
126 21.49 + 3.07 4 16.62-30.49
Spleen
8 Days NSP8
17 0. 17 ± 0. 17 2 0.00- 0.34
21 4.84 t 4.41 3 0.88-13.63
29 15.95 ± 4.84 3 9.42-25.38 94
Table 10. (Continued).
Time and X ppm DDT Number of Range in ppm Exposure Time t S.E. Subsamples DDT
Spleen
60 Days 2.61 ± 2.62 2 0.00- 5.22
91 2.88 t 1.78 4 0.00- 7.62
126 12.41 ± 2.32 4 6.91-18.08
Li ver
0 Days 9.79 t 9.82 2 0,00-19.58
17 5.40 + 2.29 4 1.46-11.99
21 10.24 t 7.66 4 1.15-33.14
29 5.22 ± 1.88 4 0.00- 8.20
60 64.95 ± 34.26 4 6.11-147.27
91 29.67 t 1 1 .41 3 8.02-51.41
126 52.65 + 12.33 4 17.87-70.60
Ki dneys
8 Days 3.83 ± 0.74 2 3.08- 4.57
17 2.23 ± 1 .47 4 0.00- 6.18
21 1 1.16 + 6.60 4 0.00-25.83
29 5.80 ± 3.45 4 0.00-15.03
60 19.81 1 9.36 4 4.36-42.28
91 8.32 ± 4.67 4 1.18-22.04
126 22.20 ± 3.96 4 12.85-31.98
Lung
8 Days 5.58 t 5.60 2 0.00-11.16 95
Table 10. (Continued).
Tissue and X ppm DDT Number Range in ppn Exposure Time ± S.E Subsamples DDT
Lung
17 Days 1.06 ± 1 .01 4 0.00- 4.09
21 5.32 ± 2.68 4 0.67-11.68
29 3.39 t 2.47 4 0.00-11.12
60 12.43 ± 5.84 4 4.86-29.53
91 6.80 ± 2.79 4 2.08-13.23
126 11.72 ± 2.39 4 5.1 1-16.37
Brain
8 Days 1.40 ± i .40 2 0.00- 2.80
17 NDb 3
21 9.43 ± 4.72 4 0.00-21.27
29 2. 15 ± 1.08 4 0.00- 7.19
60 6.30 ± 3. 15 4 0.63-18.68
91 4.56 ± 2.28 4 0.85- 8.21
126 10.05 + 5.03 4 2.90-16.07
Skin and Fur
8 Days 15.66 t 15.66 2 0.00-31.31
17 3.39 ± 2. 17 4 0.00- 9.08
21 10.07 ± 6.49 4 0.00-29.01
29 15.31 1 15.31 4 0.00-61.24
60 NSP
91 11.10 ± 6.26 3 0.00-21.63 96
Table tO. (Continued).
Tissue and X ppm DDT Number Range in ppm Exposure Time t S.E. Subsarnp les DDT
Skin and Fur
126 Days 29.53 ± 16.93 4 5. 15-78.85
a NSP No sample prepared,
b MD Not detected.
Table 11. Total body burdens and total body residue levels of DDT in the short-ta i led shrew (Blarina brevicauda), Urbana Study Area, 1969.
Days Total Body Burden Tota 1 Body Residue in jug DDTa Leve Is in ppm DDT*3
8 84.03 5.28 17 35.00 2.20 21 79. 18 4.98 29 92.96 5.85 60 167.70 12.60 91 1 1 1.68 7.02 126 217.78 13.70
a Data represent the summation of the quantities of DDT in each tissue type; each tissue was prorated for the percent weight of that tissue relative to a mean body weight of 15.9 g.
b With the exception of the 60 day collection, the total body residue levels were obtained by dividing the total body burden by the mean body v.'eight of 15.9 g. Since the skin and fur were not analyzed for the 60 day collection, the total body residue level was obtained by dividing the total body burden by 13.3 g, the mean body weight minus the mean weight for the skin and fur. Table 12. Micrograms of DDT present in the tissues and the total body of the short-tailed shrew (Biarina brevicauda), Urbana Study Area, 1969.
T i ssue Days Post-Application 8 17 21 29 60 91 126
Ske I eta I Muscle 27.03 jug 18.57 jug 34.21 jug 39.79 jug 80.91 jug 40.00 jug 66.31 jug
Heart 2.64 0.66 1.09 3.21 3.21 2.02 3.22
Spleen NSPa 0.02 0.53 1 .75 0.29 0.32 1 .37
Liver 1 1.36 6.26 1 1 .88 6.06 75.34 34.42 61 .07
Ki dney 0.77 0.45 2.23 1 .16 3.96 1 .66 4.44
Lung 1 .23 0.23 1.17 0.75 2.73 1 .50 2.58
Brai n 0.28 0.00 1 .89 0.43 ! .26 0.90 2.01
Skin and Fur 40.72 8.81 26. 18 39.81 NSP 28.86 76.78
Total Body Burden 84.03 35.00 79. 18 92.96 167.70 I I I .68 217.78
0 NSP No sample prepared. 98
Table 13. Mean percentage of the body weight and weights of individual tissues of the short-tailed shrew (Blarina brevicauda).
Ti ssue Mean Percentage of Tissue Weight Relative Body Weight3 (X t S.E.) to Mean Body Weight (Grams)
Skin and Fur 16.33 + 0.72 2.60
Feet 1 .60 + 0. 15 0.25 + Subcutaneous Fat 2.50 0.26 0.41
L i ver 7.31 + 0.16 1. 16
Ki dneys 1.24 + 0.07 0.20
Lungs 1.39 ± 0.02 0.22
Heart 0.96 + 0.04 0. 15
Sp1een 0.70 + 0.08 0. 1 1
Stomach, Intestine and Contents 14.51 + 1.81 2.31
T rachae 0.49 + 0. 18 0.08 + Tongue 0.28 0.03 0.04
Skeletal Muscle 16.46 + 0.30 2.62
Skeleton 18.49 + 0.75 2.94 + Bra i n 1 .25 0.19 0.20 + Body Fluids 16.44 1 .34 2.61
a_ X body weight = 15.9 g; n= 26.
Four animals were used in determining the relative tissue weights. 99 the assumption is made that the normal adjustments for color quenching, machine efficiency and weight (extrapolation to I.0 g of tissue) are
linear, the treated sample would produce 4377.31 dpm and contain 579.00 ppm DDT after a correction for background radiation levels. Another sample CO.0774 g) prepared from an animal collected at 29 days produced
1217.58 dpm and contained 161.18 ppm DDT a fter adjustments for color quenching, machine efficiency, weight and background radiation.
Although the number of subcutaneous fa t samples are too few in number and too variable in weight to be used in estimating DDT residue levels, these samples indicate that an unknown quantity of the insecticide does occur in this tissue. An accurate estimation of the residue levels occurring in the subcutaneous fa t might better be made in the late fa ll and early winter months when th is tissue is present in maximal amounts.
Masked Shrew - The residue levels of DDT (expressed as ppm) for the tissues of the masked shrew (Sorex cinereus) are given in Table 14.
The to ta l body burdens of DDT (expressed in micrograms DDT) and the total body residue levels (ppm) are contained in Table 15. Tissue analysis was limited to two principal tissue types because of the small size of this species: the combined ctscera including the brain, and the carcass minus the skin, feet, and skull. Since the skin, feet, and skull were not analyzed, all total body residue levels must be considered minimal. The number of micrograms of DDT present in each of the two tissue types, or the tissue burden, is given in Table 16. As in the case of the short-tailed shrew, the tissue DDT burden data were obtained by prorating the residue levels in each tissue type for the actual tissue weights. These tissue weights were based on the percentage 100
Table 14. DDT residue levels in the tissues of the masked shrew (Sorex cinereus), Urbana Study Area, 1969.
Tissue and X ppm DDT Number Range i n ppm Exposure Time ± S.E. Subsamples DDT
Skeleta1 Musele
7 Days 1.17 ± 0.64 4 0.00-2.85
16 2.03 ± 2.03 3 0.00-6.10
21 2.10 1 0.80 4 0.37-3.57
28 2.05 t 0.67 4 0.37-3.54
60 1.05 ± 0.57 4 0.04-2.28
91 1.50 ± 0.24 5 0.76-1.94
126 0.92 ± 0.35 4 0.00-1.68
Viscera
7 Days 0.59 t 0.26 . 4 0.00-1.26
16 1.59 ± 1.59 3 0.00-4.76
21 0.78 t 0.31 4 0.00-1.46
28 2.43 t 0.76 4 0.96-4.17
60 0.94 t 0.49 4 0.00-2.19
91 1.95 ~ 0.42 5 0.78-3.32
126 1.15 1 0.40 4 0.01-1.82 Table 15. Total body burdens and total body residue levels of DDT In the masked shrew (Sorex ci nereus), Urbana Study Area, 1969.
Days Total Body Burden Total Body Residue in jjg DDTa Levels in ppm DDT*3
7 1.92 0.68
16 3.85 1.36
21 3.20 1. 13
28 4.63 1 .63
60 2. 10 0.74
91 3.55 1.25
26 2. 13 0.75
a Data represent the summation of the quantities of DDT in the two tissue types; each tissue was prorated for the per cent weight of that tissue relative to a mean body weight of 3.34 g.
b The total body residue levels were obtained by dividing the total body burden (jug DDT) by 2.84 g, the mean body weight minus the mean weight for skin and fur. 102
Table 16, Micrograms of DDT present in the tissues and the total body of the masked shrew (Sorex cinereus) , Urbana Study Area, [969.
Days Post- Total Body Burden App1i cation Skeletal Muscle V i scera i n ,ug DDT
7 1 .39 0.53 1 .92
16 2.42 1 .43 3.85
21 2.50 0.70 3.20
28 2.44 2.19 4.63
6Q 1.25 0.85 2. 10
91 1.79 1.76 3.55
126 1.09 1.04 2. 13
Table 17. Mean percentage of the body weight and weights of individual tissues of the masked shrew (Sorex cinereus).
Ti ssue Mean Percentage of Tissue Weight Relative Body Weight3 (X t S.E.) to Mean Body Weight*3 (Grams)
Skin and Fur 15.03 t 0.47 0.50
Feet 0.02 0.001
Skeletal Muscle excludi ng Sku11 35.64 t 0.81 1.19
V i scera 26.83 t 1 .40 0.90
Skul 1 9.52 + 0.68 0.32
Body Fluid 12.99 ± 1.26 0.43
a_ X body weight = 3.34 g; n= 28.
b Four animals were used in determining the relative tissue weights. weight represented by each tissue type relative to a mean body weight of
3.34 g. The percent weight of each tissue type was derived from the
dissection of adult masked shrews (n = 4); the mean body weight was
based on the weights of a ll masked shrews collected and analyzed from the study area during 1969 (n = 28). The per cent weight and the
actual weight of each tissue type are contained in Table 17. The total body residue levels (ppm) were obtained by summing individual tissue burdens tug DDT) and dividing the total body burden by 2.84 g, the mean body weight minus the mean weight of the skin and fur. No significant
linear relationship (P < 0.05) was detected between time and the residue levels of either the individual tissue types or the total body.
Meadow vole - During 1968, the meadow vole (Microtus pennsyI vanicus) population on the study area was so low that no relia b le estimate of population size could be obtained by means of Iive-trapping. The observation of meadow vole sign (runways, droppings, nests, etc.)
indicated th a t the study area had in the not too distant past supported a large population of voles. This fact was true not only for the study area but also for the Urbana W ild life Area as a whole and fo r the surrounding areas of Champaign County. However, through the Iive- trapp ing and stocking of voles obtained in Delaware County where populations were high, a vole population of sufficient size to allow repeated sampling was established on the study area by the spring of
1969.
The tissue residue levels of DDT and the total body residue levels detected in meadow voles are given in Table 18. The number of micro grams of DDT present in each tissue type, or the tissue burden, is 104 given in Table 19. The tissue DDT burden data were obtained by prorating the residue levels for each tissue type for the actual tissue weight based on the per cent weight of each tissue type relative to a mean body weight of 32.90 g. The percent weight of each tissue type was based on the tissue weights of dissected adult animals (n=4).
The mean body weight was derived from the weights of a ll meadow voles collected and analyzed from the study area In 1969 (n=22). The weights of the individual tissues and the percentage of the mean body weight they represent are given in Table 20. The to ta l body residue levels Cpprn
DDT) were obtained by summing individual tissue burdens (;jg DDT) and dividing the to ta l body burden by the mean body weight of 32.90 g.
Twenty-two voles (13 females and nine males) were collected from the study area during six separate collection periods. Only two of this number were juveniles. DDT was detected during all collection periods in the skeletal muscle and liver. The maximum residue levels detected in the la tte r two tissue types were 0.31 and 2.95 ppm, respectively. Residues were detected during one or more collection periods in the heart, lungs, brain, and skin and fur. As the data suggested in the case of the short-tailed shrew, the presence of DDT residues in the lungs and heart also suggest that a respiratory route of entrance may be involved in the meadow vole. The total body residue levels for th is species ranged between 0.04 ppm and 0.18 ppm; the mean total body residue level was 0.10 ppm. No significant linear relation ship CP< 0.05) was detected between time and the residue levels of either the individual tissues or the total body. Table 18. DDT residue levels in the tissues of the meadow vole (Microtus pennsy1 vanicus), Urbana Study Area, 1969.
Tissue Days Post-App1i cation
7 13 28 60 91 125
Skeletal Muscle
X ppm DDT + S.E. 0.20 ±0-11 0.13 ± 0.05 0.10 + 0.09 0.13 ± 0.13 0.31 ± 0.07 0.02 ± 0.03
Number Subsamples 4 4 2 4 4 4
Range i n ppm DDT 0.00- 0.49 0.00-0.24 0.01-0.18 0.00-0.13 0. 18-0.42 0.00-0.06
Heart
X ppm DDT ± S.E. NDa 0.19 ± 0.19 ND ND ND ND
Number Subsamples 4 4 2 4 4 4
Range in ppm DDT 0.00-0.76
Spleen
X ppm DDT ± S.E. ND ND ND ND ND ND
Number Subsamples 4 3 1 4 4 4
Range in ppm DDT
Liver
X ppm DDT ± S.E. 0.47 ± 0.42 1 .10 ±0.58 2.95 ± 0.40 0.35 ± 0.33 0.97 ± 0.19 1.07 ± 0.49 Table 18. (.Continued).
Tissue Days Post-Application
13 28 60 91 125
Liver
Number Subsamples 4 4
Range in ppm DDT 0.00-1.71 0.00-2.10 2.54-3.35 0.00-1.33 0.58-1.34 0.00-2.20
Lung
X ppm DDT ± S.E. ND 2.05 ± 1.03 ND I . I I ± 0.56 0.34 ± 0.17 ND
Number Subsamples 4 4 2 4 4 4
Range in ppm DDT 0.00-4.99 0.00-4.43 0.00-1.34
Bra i n
X ppm DDT + S.E. ND ND ND ND 0.59 ND
Number Subsamples 4 I 2
Range in ppm DDT
Ki dneys
X ppm DDT ± S.E. ND 1.02 ± 0.76 ND 0.19 ± 0.19 ND ND
Number Subsamples 4 4 4 2 4 4 o O' Table 18. (.Continued).
Tissue Days Post-App! 1icat ion
7 13 28 60 91 125
Ki dneys
Range in ppm DDT 0.00-3.22 0.00-0.76
Skin and Fur
X ppm DDT ± S.E. NSPb 0.35 t 0.34 ND NSP ND ND
Number Subsampies 4 2 4 4
Range In ppm DDT 0.00-1.37
Total Body Residues0 0.07 0. 14 0.18 0.05 0.12 0.06
a ND Not detected
b NSP No sample prepared
c With the exception of the 7 and 60 day collections, the total body residue levels were obtained by dividing the total number of micrograms of DDT by the mean body weight of 32.90 g. Since the skin and fur were not analyzed for the 7 and 60 day collections, the total body residues were based on a body weight of 29.19 g, the mean body weight minus the weight of the skin and fur. Table 19. Micrograms of DDT present in the t i ssues and the toial body of the meadow vole (Mi crotus pennsy1 vanicus), Urbana Study Area, 1969.
Days Post-App1i cat iion
7 13 28 60 91 126
Skeletal Muscle 1.12 pg 0.73 pg 0.56 pg 0.73 jug 1.74 ;jg 0.1! jug
Heart NDa 0.04 ND ND ND ND
Sp ieen ND ND ND ND ND ND
Liver 0.88 2.06 5.52 0.60 1.81 2.00
Lung NSPb 0.1 1 ND NSP 0. 1 1 ND
Ki dneys ND 0.39 ND 0.07 ND ND
Bra i n ND ND ND ND 0.40 ND
Skin and Fur NSP 1.30 ND NSP ND ND
Total Body Burden 2.00 4.63 6.08 1.45 4.06 2. 1 1
a ND Not detected.
b NSP No sample prepared 109
Table 20. Mean percentage of the body weight and weights of individual tissues of the meadow vole CMicrotus pennsyIvanicus?.
Tissue Mean percentage of Tissue Weight Relative Body Weight3 (X t S.E.) To Mean Body Weight^3 CGrams)
Subcutaneous Fat 0.79 + 0.15 0.26
Skeletal Muscle 17.06 i- 1 .34 5.61
Heart 0.60 + 0.05 0.20
Spleen 0.73 ± 0. 16 0.24
Liver 5.69 + 0. 12 1 .87
Ki dneys 1.17 + 0.06 0.38
Lung 0.94 + 0.09 0.31
Bra i n 2.07 + 0.26 0.68
Skin and Fur 1 1 .27 + 0.08 3.71
Feet 1.61 ± 0.08 0.53
Stomach, Intestine and Contents 6.07 ± 5.87 2.00
Tongue 0.35 + 0. 12 0. 12
Ske1eton 20. 19 + 0.90 6.64
Trachae 0.21 + 0.01 0.07
Occular Fat 0.27 + 0.01 0.09
Glandular Material From Throat Region 1.44 + 0.45 0.47
a_ X body weight = 32.90 g; n=22.
b Four animals were used in determining the re la tive tissue we i ghts. I 10
Mink - Between June 19 and June 23, 1969, seven mink CMusfela vison) ,
an adult female and a lit t e r of six juveniles, were captured cn the study
area. Although the gradual removal and residue analysis of these animals
over the course of the summer would have been desirable, the predation
of the mink upon wing-clipped pheasants released on the study area fo r
future monitoring purposes necessitated th e ir immediate removal. The
DDT residue levels for selected tissues of the adult and juvenile mink
are given in Tables 21 and 22, respectively. Residue levels representing
the combined data from both age groups are given in Table 23. Wild
control mink were obtained from a local fur dealer during the fall of
1969.
The highest residue levels were detected in subcutaneous fa t
(4.24 ppm). This tissue was found in quantities sufficient for sample
preparation only in two juvenile mink. These two animals, both males,
had individual residue levels of 3.45 and 5.03 ppm. DDT residues were
found in the heart of juvenile mink (1.30 ppm) but not in the heart of the adult. Juvenile mink also contained residues in the submaxillary
gland CO.94 ppm), whereas none was found in the submaxillary gland of the adult. The mammary tissue of the adult contained 2.86 ppm DDT.
The juvenile mink at the time of their capture had been weaned and were actively engaged in hunting excursions with the adult female.
The l it t e r was composed of four males (mean weight: 412.6 g) and two females (mean weight: 272.0 g). The largest member of the lit t e r , a male, weighed 4S2.I g, only 9.5 g lig hte r than the adult female.
Based on the contents of droppings and upon the well-cleaned carcasses found on the study area, the diet of the mink during the short period Ill
Table 21. DDT residue levels in the tissues of an adult female mink (Mustela vison) , Urbana Study Area, June 20, 1969.
Tissue ppm DDT
Mammary Tissue 2.86
Skeletal Muscle NDa
Heart ND
Sp1een ND
Liver 0.17
Ki dney ND
Adrena 1 ND
Lung ND
Bra i n 0.01
Skin and Fur ND
Submaxi 1lary Gland ND
Fat from Abdominal Cavity 2. 14
a ND Not detected. I 12
Table 22. DDT residue levels in the tissues of juvenile mink (MusteI a vison), Urbana Study Area, June 19 through June 23, 1969.
Ti ssue X ppm DDT Number Range in ppm ± S.E. Subsamp1es DDT
Subcutaneous Fat 4,24 ± 0.79 2 3.45-5.03
Skeleta1 Musele 1 .33 ± 1.33 6 0.00-7.96
Heart 1 .30 ± 0.84 6 0.00-4.80
Sp leen NDa 6 0.00
Liver 1.06 + 0.78 6 0.00-0.63
Kidney ND 6 0.00
Adrena1 ND 6 0.00
Lung 0.32 t 0. 13 6 0.00-1.94
Bra i n 0.28 ± 0.28 6 0.00-1.70
Skin and Fur ND 5 0.00
Submaxi 11ary Gland 0.94 ± 0.25 5 0.00-1.47
Fat from Abdomi na1 Cavi ty ND 2 0.00
a ND Not detected. I 13
Table 23. DDT residue levels in the tissues of adult and juvenile mink (Mustela vison), Urbana Study Area, June 19 through June 23, 1969.
Tissue X ppm DDT Number Range in ppm + S.E. Subsamp1es DDT
Subcutaneous Fat 3.78 + 0.65 3 2.86-5.03
Skeleta1 Muse 1e 1.14 + 1.14 7 0.00-7.96
Heart 1.11 + 0.42 7 0.00-4.80
Spleen NDa 7 0.00
Liver 0.14 + 0.09 7 0.00-0.63
Ki dney ND 7 0.00
Adrena1 ND 7 0.00
Lungb 0.32 1 0.13 6 0.00-1.94
Brai n 0.24 ± 0.24 7 0.01-1.70
Skin and Fur ND 5
Submaxi 1lary Gland 0.78 + 0.27 6 0.89-1.47
Fat from Abdomi na1 Cavi ty 0.71 + 0.71 3 0.00-2.14
a ND Not detected.
b Juveniles only. 114 following application of the DDT (9 to 13 days) had been restricted prim arily to pheasant. One pheasant having a short exposure period
(2 days) running concurrent with the exposure period of the mink had a residue level of 0.45 ppm in the kidney; no other tissues contained DDT residues (see section on pheasants). Additional sources of DDT available to the mink would have been the ingestion of the insecticide through grooming behavior and the predation upon small mammals, prim arily shrews.
Cottontail rabbit - The DDT residue data for cottontail rabbits
(Sylvi lagus floridanus) (.Table 24) are grouped according to exposure time rather than capture date. Four of the 14 rabbits collected during
1969 were juveniles which were born a fter the date of the insecticide application. The remaining 10 rabbits were present on the study area at the time of application either as native or stocked individuals.
Id e n tifica tio n of exposure groups was determined by ear-tags in the case of previously handled adults and by eye lens weight (Lord, 1959) in the case of non-handled adults and juveniles. None of the rabbits analyzed carried DDT residues in the skeLetal muscle. However, residue levels ranging between 0.03 and 1.86 ppm were detected in the heart, liver, kidney, spleen, lung brain, fat from abdominal cavity, and skin and fur.
A significant positive linear relationship (P< 0.05) was detected between time and the residue levels in the liver (t = 3.472; df = 4).
The residue levels of all other tissue types were not significantly related with time.
Wood Mouse - Only a small population of wood mice (Peromyscus leucopus) occurred on the study area during 1969. However, a maximum population I 15
Table 24, DDT residue levels in the tissues of cottontail rabbits (Sylvi laqus floridanus), Urbana Study Area, 1969.
Tissue and X.ppm DDT Number of Range in ppm Exposure Time ± S.E. Subsamples DDT
Skeletal Muscle
7 Days ND 4
22 ND 4
54 ND 4
71 ND 4
91 ND 2
I 13 ND I
Heart
7 Days 0.61 ± 0.60 4 0.00-2.40
22 ND 2
54 0.16 + 0.16 4 0.00-0.62
71 0.49 1
91 0.41 ± 0.01 2 0.40-0.42
I 13 0.14
Spleen
7 Days ND
22 ND
54 0.25 ± 0.25 0 .0 0 -0 .5 0
71 ND
91 ND
I 13 ND I 16
Table 24. (Continued).
Tissue and X ppm DDT Number of Range in ppm Exposure Time ± S.E. Subsamples DDT
Liver
7 Days 0.05 t 0.05 4 0.00-0.21
22 0.03 t 0.02 2 0.00-0.06
54 0.13 + 0.12 4 0.00-0.47
71 0.16 1
91 0.35 + 0.09 2 0.22-0.47
1 13 0.23 1
Kidney
7 Days 0.09 ± 0.06 4 0.00-0.25
22 0.47 + 0.06 2 0.41-0.53
54 0.35 + 0.04 4 0.25-0.41
71 1.10 1
91 1.00 ± 0.21 2 0.79-1.20
1 13 0.75 1
Lung
7 Days 0. II ± 0.06 4 0.00-0.23
22 ND 2
54 0.71 ± 0.42 4 0.05-1.94
71 1.02 1
91 0.73 ± 0.38 2 0.35-1.10
1 13 ND 1 I 17
Table 24. (Continued).
Tissue and X ppm DDT Number of Range in ppm Exposure Time t S.E. SubsampIes DDT
Bra i n
7 Days ND 4
22 1.86 ± I .86 2 0.00-3.72
54 0.18 ± 0.10 4 0.00-0.72
71 0.78
91 0.36 ± 0.13 0.23-0.48
I 13 0.84
Skin and Fur
7 Days NSPb
22 ND
54 ND
71 1.95
91 ND
113 ND
Fat from Abomlnal Cav i ty
7 Days 0.76 ± 0.76 0.00-1.52
22 NSP
54 1.37
71 NSP I 18
Table 24. (Continued).
Tissue and X ppm DDT Number of Range fn ppm Exposure Time ±.S.E. Subsamples DDT
Fat from Abomina! Cavi ty
91 Days 0.05 ± 0.04 2 0.00-0.09
1 13 NSP
a ND Not detected.
b NSP No sample prepared. I 19 of 40 individuals was estimated to have been present during the late summer and fa ll of 1968. This population decrease in 1969 can not be attributed to the insecticide since the population had undergone a decrease p rio r to the application, apparently as a result of natural winter mortality. Although an occasional individual wood mouse was taken in live traps during the earlier part of the summer, the collection of this species for residue analysis was postponed unti I fall to take advantage of a maximum exposure period.
Six individuals were collected from the study area in September and October, 91 days and 125 days post-application, respectively. The
September collection consisted of four mice, two adult males (mean weight: 17.3 g) and two adult females (mean weight: 19.1 g). Two individuals were collected in October, an adult female (21.7 g) and a juvenile female (14.2 g ). Although the animals were categorized as to age by observation of weight and pelage, their exact age and exposure time can only be speculative. As with the other species of small mammals analyzed during this study, no reliable method of aging was available for the wood mouse. The DDT residue data for the wood mouse is given in
Table 25.
Red-winged blackbird - The residue levels of DDT detected in the tissues of the red-winged blackbird (Aqelaius phoeniceus) collected from the study area on June 19, 1969 (9 days post-application), are given in
Table 26. All of the birds were displaying territorial behavior and are believed to have been occupying breeding te rrito rie s w ithin the confines of the 4.05-ha study plot when collected. The collection was 120
Table 25. DDT residue levels in the tissues of the wood mouse (Peromyscus leucopus), Urbana Study Area, 1969.
Days Post-Application
91 125
Skeletal Muscle
X ppm DDT ± S.E. 0.25 ± 0.12 NDa
Number Subsamples 4 2
Range in ppm DDT 0,10-0.60
Hea rt
X ppm DDT i S.E. ND ND
Number Subsamples 4 2
Range i n ppm DDT
Liver
X ppm DDT ± S.E. 0.70 + 0.22 0.10 - 0.09
Number Subsamples 4 2
Range in ppm DDT 0.19-1.27 0.00-0.19
Kidneys
X ppm DDT ± S.E. ND ND
Number Subsamples 3 2
Range in ppm DDT
Lung
X ppm DDT ± S.E. ND ND
Number Subsamples 4 4
Range in ppm DDT 121
Table 25. (Continued).
Days Post-Application
91 125
Brai n
X ppm DDT 1 S.E. ND 1.07 ± 1.07
Number Subsarnples 4 2
Range in ppm DDT 0.00-2.13
Skin and Fur
X ppm DDT 1 S.E. 0.27 ± 0. 18 ND
Number Subsamples 4 2
Range i n ppm DDT 0.00-0.76
a ND Not detected. 122 composed of two adult' females (39.4 and 33.3 g) and two males (63.5 and
59.7 g). The highest residue level occurred in the liver Cl.II ppm);
DDT residues were also detected in the lung, gizzard, breast muscle, leg muscle, and brain. No residues were detected in the heart.
Table 26. DDT residue levels in the tissues of adult red-winged black birds (Agelaius phoenicous), Urbana Study Area, June 19, 1969 (9-days post-oppIi cation).
Ti ssue X ppm DDT Number of Range in ppm ± S.E. Subsamples DDT
Leg Muscle 0.1 1 ± 0.06 4 0.00-0.27
Breast Muscle 0.06 + 0.06 3 0.00-1.43
Heart NDa 4
Gi zzard 0.28 + 0.14 4 0.05-0.68
Li ver 1,11 ± 0.45 4 0.00-2.03
Lung 0.49 + 0.35 2 0.13-0.85
Bra i n 0.05 ± 0.03 3 0.-0-0.14
a ND Not detected. Ring-necked pheasant - Twelve wing-clipped pheasants (Phas?anus
colchicus; six cocks and six hens) were released into the study area
several hours after the insecticide application on June 10. These birds were released by the investigator with tv/o objectives in mind: I) to
measure the rate of DDT accumulation acquired through biological magnification and 2) to determine the likelihood of pheasants acquiring
DDT by picking up the insecticide-laden granules while foraging for food
and grit. The latter objective was included at the request of biologists
from the Ohio Division of W ildlife to obtain more data on granular
pesticide uptake by gallinaceous birds under agricultural conditions.
The latter objective necessitated an early harvest of a portion of the
pheasants so as to exclude the likelihood of the acquisition of the
insecticide through food chain, or biological magnification.
On June 12, five of the 12 pheasants released on June 10 were
found dead as the result of mink predation. Four of the five birds had been completely devoured with nothing remaining but we 11-cleaned
skeletons and feathers. The f if t h pheasant (cock),which bore no mark and apparently died of overheating while attempting to escape the mink, was analyzed for DDT residues. Later hunting drives across the area
as well as the presence of the investigator and assistant on the study
area during other collection activities failed to reveal the whereabouts of the remaining seven pheasants.
On June 27, a second group of 15, wing-ciipped pheasants
(five adults, one cock and four hens; 10 juveniles, five cocks, and
five hens) was released onto the study area. Although a bird dog and several hunters were used, only three (two adult hens and one juvenile 124
hen) of the 15 pheasants were recovered (July 2, 22 days post-application
and 5 days after release). The only other pheasant collected was a
juvenile male (120.0 g) taken on September 10. It is believed that this
bird was the product of a late nesting attempt by undetected birds from
e a rlie r releases. A downy pheasant chick had been seen on the area in
mid-August; the col Icctod juvenile bird is assumed to have been a part of
the same brood.
The ring-necked pheasant residue data are given in Table 27.
The male pheasant taken on June 12 (2 days post-application) had
detectable DDT residues only in the kidney (0.45 ppm). No residues were
found in the leg muscle, breast muscle, heart, live r, gizzard, brain,
large intestine and small intestine. Among those birds from the second
release collected on July 2 (22 days post-application and 5 days after
release), DDT was found in the large intestine (0.23 ppm) of one of the
two birds fo r which th is tissue was analyzed. The residues in the kidney
and large intestine of the above pheasants are probably indicative of
the ingestion of DDT-impregnated granules. The juvenile collected on
September 10 (92 days post-application) contained residues in the breast muscle (0.13 ppm), heart (0.95 ppm), gizzard (0.38 ppm), small intestine
(0.40 pprn), and brain (0.41 ppm). Other tissues analyzed but containing
no DDT residues were leg muscle and live r. The DDT residues in th is
bird can be attributed to I) the later collection date and the wider
distribution of the insecticide within the old-field food web and 2) the higher proportion of invertebrates normally occurring in the diet of juvenile birds. Intact granules were not present on the study area by the time the la tte r bird was hatched. 125
Table 27. DDT residue levels in the tissues of the ring-necked pheasant (Phasianus colchicus), Urbana Study Area, 1969. '
Tissue and Days X ppm DDT Number of Range i n Post-App1i cat i ona + S.E. Subsamp1es ppm DDT
Leg Muscle
2 Days NDb 1
22 ND 3
92 ND 1
Breast Muscle
2 Days ND 1
22 ND 3
92 0.13 1
Heart
2 Days ND 1
22 ND 3
92 0.95 1
Li ver
2 Days ND 1
22 ND 3
92 ND 1
Ki dney
2 Days 0.45 1
22 ND 3
92 NSPC 126
Table 27. (Continued).
Tissue and Days X ppm DDT Number of Range in Post-App1i cation ± S.E. Subsamp1es ppm DDT
Gi zzard
2 Days ND 1
22 ND 3
92 0.38 1
Brai n
2 Days ND 1
22 ND 3
92 0.41 1
Large Intestine
2 Days ND 1
22 0.23 ± 0.23 2 0.00-0.46
92 NSP
Sma11 1ntestIne
2 Days ND 1
22 ND 2
92 0.40 1
a The actual exposure time for the bird collected at 2 days post application was 2 days; however, the exposure time for the bird taken at 22 days was 5 days due to a later release date. The bird taken at 92 days post-application was a juvenile assumed to have been hatched on the study area sometime a fter mid-summer. The exact exposure time of the la tte r bird is unknown.
^ND Not detected. £ NSP No sample prepared. Garter snake - D ifficulty was experienced in capturing garter snakes
(Thamnophis s i r t a li s ) on the study area due to the dense vegetative cover. Those snakes which were captured, a total of four individuals, were taken by hand as they basked in the sun in narrow paths (inadver tently created by the investigator) which criss-crossed the study area between grid stations. Subsamples from these four individuals were limited to two tissue types, skeletal muscle and the combined viscera
(hornogenate). The decision to subsample the snakes in th is manner rather than on the basis of individual tissues or organs was necessitated by the small size of the firs t snake collected (12.7 g at 17 days post application). Although the remaining individuals taken at 83 days and
126 days were larger (30.1 g, 36.1 g, and 39.4 g), consistency required that the subsampling procedure used with the f i r s t snake be continued with the remaining individuals.
DDT residues were detected in snakes taken during two of the three collection periods (Table 28). The highest residue levels in both the skeletal muscle and viscera (2.50 ppm and 31.50 ppm, respec tively) were detected in the individual taken at 17 days post-applica tion. Lower residue levels were detected in skeletal muscle and viscera of the snakes collected at 126 days (0.03 ppm and 2.66 ppm, respectively) no DDT residues were detected in either tissue type of the individual collected at 83 days. Although the actual exposure time of a ll four individuals remains unknown, the wide variation in residue levels suggests that only the 17 day specimen was exposed to the study area for the full time that the capture dates would indicate.
Although the study area was surrounded at the base with a 128 buried sheet metal h a rrie r topped with an e le c trifie d wire strand, access to the study area from the outside by snakes was a p o s s ib ility .
Movement from the study area to the outside, however, was less lik e ly .
On several occassions the remains of electrocuted garter snakes, appar ently attempting to enter the study area, were found on the electric
fence. However, entrance was s till possible,without the snake touching the electric fence. The points of capture of the snakes, although not conclusive, lend support for this hypothesis. The snakes taken at 17 days and 126 days, ail of which had detectable quantities of DDT in at
least one of the two tissues analyzed, were captured toward the center of the study area. The snake which was collected at 83 days and which had no detectable DDT residuos was captured near the fence, suggesting that its residency on the study area had been brief. 129
Table 28. DDT residue levels in the tissues of the garter snake (Thamnophis sirtalis), Urbana Study Area, 1969.
Days Post-Application
17 83 126
Skeletal Muscle
X ppm DDT ± S.E. 2.50 NDa 0.03 ± 0.03
Number Subsamples I 1 2
Range in ppm DDT 0.00-0.06
Viscera
X ppm DDT ± S.E. 31.50 ND 2.66 + 0.67
Number Subsamples 1 1 2
Range in ppm DDT 1.99-3.33
a ND Not detected. 130
Study Pond Monitoring Data
Vegetation - Two species of subinergent plants, water m ilfoil
(Myriophyllum sp.) and stonewort (Chara sp.) were collected on five occasions between mid-June and mid-September (Table 29). DDT residues were detected in the water m ilfoil at 15 and 91 days post-application.
Residues were also detected in stonewort at 64 days. Samples of a filamentous alga (ChIorphyceae) taken at 15, 31, 64, and 91 days contained no DDT residues.
Aquatic Insects - Dragonfly nymphs (Aeschnidae) and backswimmers
(Nolonectidae) were collected and prepared for analysis as homogenates of whole organisms. No DDT residues were found in either insect family
(Table 30).
Vertebrates - Three species of vertebrates, the flathead minnow
(Plmephales promelos), cricket frog (Acri s qryI I us), and bullfrog tadpole (Rana catesbeiana) , were collected and analyzed during the summer (Table 31). Samples of adult bullfrogs were also taken on two occasstons. All vertebrate samples with the exception of the adult bull frogs were prepared from homogenates of whole organisms. Individual tissues (liv e r, skin, and skeletal muscle) were used in sample preparation in the case of the adult bullfrogs. No DDT residues were detected in the flathead minnows or the cricket frogs. However, DDT was found in the bullfrog tadpole at 9, 15, 31, and 64 days. DDT was detected in the skin and liver of the adult bullfrogs taken at 15 and
31 days (Table 32). No residues were found in the skeletal muscle. 131
Table 29. DDT residue levels in study pond vegetation, Urbana Wildlife Area, 1969.
Species and Days X-ppm DDT Number of Range 1n ppm Post-App1i cation + S.E. Subsamp1es DDT
Myriophy11um sp.
9 Days NDa 4
15 I .52 + 1.52 4 0.00-6.07
31 ND 4
64 ND 4
91 0.56 ± 0.39 4 0.00-1.66
Chara sp.
9 Days ND 4
15 ND 4
31 ND 4
64 0.81 ± 0.22 4 0.26-1.29
91 ND 4
FI 1amentous A1ga
9 Days NSCb
15 ND 4
31 ND 4
64 ND 4
91 ND 4
a ND Not detected.
b NSC No sample collected. 132
Table 30. DDT residue levels in study pond insecta, Urbana Wildlife Area, 1969.
Family and Days X ppm DDT Number of Range in ppm Post-App1i cation Subsamples DDT
Aeschnidae
9 Days NDa 4
15 ND 4
31 ND 4
64 ND 4
91 ND 4
Notonectidae
9 Days NSCb
15 ND 2
31 ND 4
64 ND 4
91 ND 4
a ND Not detected.
b NSC No sample collected. 133
Table 31. DDT residue levels in study pond vertebrates, Urbana Wildlife Area, 1969.
Species and Days X ppm DDT Number of Range in ppm Post-App1i cati on ± S.E. Subsamples DDT
Pimephales promelas
9 Days NDa 4
J5 ND 4
31 ND 4
64 ND 4
91 ND 4
Acri s pry 11 us
9 Days ND 4
15 ND 4
31 ND 4
64 ND 4
91 ND 4
Rana catesbeiana Tadpole
9 Days 2.35 ± 0.84 4 0.00-3.99
15 1.35 ± 0.70 4 0.00-2.93
31 0.17 + 0.17 4 0.00-0.67
64 5.38 1
91 ND 4
a ND Not detected. 134
Table 32. DDT residue levels in the tissues of the adult bullfrog (Rana catesboiana) from the study pond, Urbana W ild life Area, 1969.
Tissue and Days X ppm DDT Number of Range in ppm Post-App 1 i cat i on ± S.E. Subsamples DDT
Skin
15 Days 0.37 ± 0.37 4 0.00-1.47
31 0.11 ±0.11 4 0.00-0.43
Skeletal Muscle
15 Days NDa 4
31 ND 4
Liver
13 Days 0.03 ± 0.02 2 0.00-0.48
31 0.89 ± 0.64 2 0.00-2.69
a ND Not detected. 135
Bottom Soil - Samples of the pond bottom soil were collected at 31, 65, and 92 days to determine the possible deposition of DDT by run-off from the study area. However, no DDT residues were detected in any of the collections. Control samples were taken from a pond located on the
Urbana Area approximately 0.25 mile south of the study pond.
V/ater Samples - As the residues in the aquatic plants and animals indicate, DDT was transported by run-off from the study area to the pond. The particulate matter sample taken at 3 days showed no DDT to be present. However, particulate matter samples taken at 6, 9, and 15 days contained DDT residues of 50, 3860, and 4390 ppb (part per b illio n ) , respectively. No DDT was detected in particulate samples collected during the remainder of the summer (23, 37, 56, 78, 91, and 133 days).
DDT was not detected in the hexane-extracted total water samples during the course of the summer. The number of subsamples per sample, or collection period, was limited to one subsample for particulate and total water samples during the firs t month post-appIication due to the small volume of water collected. All samples collected after this time were composed of four subsamples.
The presence of DDT in the particulate samples during the f i r s t
3 weeks indicates that the insecticide was s till associated to some degree with the clay granule c a rrie r. Its absence from the samples taken a fte r the f i r s t month probably marks the complete leaching of the
DDT from the granules and its incorporation into the old-field detritus.
Partial leaching of the insecticide and its entrance into the old-field ecosystem had occurred, however, within the f ir s t week following the application as indicated by the residues present in the two species 136
of shrews.
As stated above, no DDT residues were found in tfie so? I samples
from the pond bottom. It is assumed that the particulate matter and its
associated DDT would have been deposited at the bottom of the pond.
However, the dense submergent vegetation likely intercepted the particu
late matter as shown by the DDT residues in Chara and MyriophyIlum.
Under these circumstances, DDT would not be found in the soil until the
plants began to decay in the late fa ll or winter.
Vegetation Biomass Data
Since different species achieve their maximum biomass at different
times during the growing season, the peak net primary production fo r the
o ld -fie ld community was obtained by summing the mean biomass peaks
for individual species. The peak biomass of individual species and the
percent of the to tal biomass represented by that species are given In 2 Table 33. An estimated 447.1 g dry weight per m of herbaceous vegeta tio n were produced on the 4.05-ha UO-acre) study site between Apri J
and October. This estimate of productivity includes the biomass
produced by two species, Pastinaca sativa and Dactyl is glomerata, during
two separate growth intervals. The f ir s t growth peak for Pastinaca occurred during late June. By this date the latter species had reached
Its maximum height and had flowered. Shortly thereafter, the plant was
attacked by ca te rp illa rs and died back to ground level. A second growth
period occurred between early June and October. A sim ilar two-phase growth pattern was evident in DactyI is , the f ir s t growth peak occurring
in mid-August and the second peak occurring in mid-October. 137
Grasses and sedges accounted for 68. A% or 305.7 g dry weight per m of the total net primary production; forbs accounted for 31.6$ O or 141.5 g dry weight per m . The mean biomass fo r individual species during each collection interval is given in Table 34. Frequency of occurrence and percent frequency of occurrence data derived from c lip - plot data are given in Table 35. 138
Table 33. Peak biomass and percent of total vegetation biomass represented by individual species. Biomass expressed as grams dry weight per square meter.
Species Peak Biomass Percentage of Total Biomass
Agropyron repens 116.8 g/m^ 26. 1 $ Dactyl is glomerata3 88.7 19.8 Poa spp. 82. 1 18.4 Pastinaca sativa^ 42.2 9.4 Daucus carota 35.4 7.9 Phleum pretense 12.5 2.8 Lysimachia sp. 10.5 2.4 Solidago juncea 9.5 2. 1 Aster ericoides 8.2 1.8 Cirsium spp. 7.7 1.7 Physa1i s long i fo 1i a 6.9 1.5 Carex spp. 5.5 1.2 Nepeta cataria 4.0 0.9 Erigeron phi1ade1phicus 3.5 0.8 Plantaao spp. 3.2 0.7 Aster sp. 2.4 0.5 Achi 1 1 ea rni 1 lefol i urn 1.5 0.3 Lycopus sp. 2.2 0.5 Prune 1 1 a vu1 gari s 1 .3 0.3 Potenfilla recta 0.8 0.2 Apocynum cannabinum 0.8 0.2 Rumex crispus 0.6 0.1 Oxalis europaea 0.3 0. 1 Ambrosia a rte m is iifo lia 0.2 0.04 Li nar i a vu1qari s 0.2 0.04 Setaria glauca 0. 1 0.02
Total Vegetation Biomass 447. 1
a Species having two peak growth periods during single season. 139
Table 34. Vegetation mean biomass data derived from c lfp -p lo t samples collected during 1969, Urbana Study Area.
COLLECTION DATE
4.7 5/7 6/24 8/14 9/11 10/21
Number of Subsamples 16 15 12 12 12 12
Ci rs i um spp g/m2 0.44 2.96 4.72 7.68 6.36 + S.E. 0.40 I .96 3.08 4.84 4.12
QxaIis europaea g/m2 0.16 0.32 0.32 __ t S.E. 0.12 0.09 0.20
Li nari a vulgaris
g /m 2 0.20 _ 10.32 ± S.E.
Potenti I I a recta g/rn2 0.80 0.44 ± S.E.
Lys1mach ia quadri fo lia g/m2 10.52 ± S.E.
Ambrosia a rte m is iifo lia g/m2 0.20 0.12 ± S.E. 0.16
Plantago spp. g/m2 0.12 0.40 3.20 1.12 ± S.E. 0.37 0.32
Aster sp. g/m2 0.24 ___ 2.40 1.00 ± S.E. 1.58 0.90
Rurnex cri spus g/m2 0.60 + S.E. 140
Table 34. (Continued).
COLLECTION DATE
4/7 5/7 6/24 8/14 9/11 10/21
Number of Subsamples 16 15 12 12 12 12
Nepeta cataria g/m2 3.98 ± S.E. 3.72
Agropyron repens g/m2 4.16 17.48 116.76 77.36 38.92 18.36 ± S.E. 1.50 7.24 50.25 25.02 16.61 8.36
Poa spp. g/m2 7.32 64.60 74.96 82.12 36.76 25.44 ± S.E. 1.83 9.55 22.74 22.87 11.60 6.60
Daucus carofa g/m2 0.04 2.92 3.72 11.16 35.40 7.76 + S.E. 0.03 1.76 2.55 7.68 15.93 3.40
Pastj naca sati va g/m2 0.06 11.32 23.00 8.08 27.32 24.16 ± S.E. 2.87 8.04 7.05 11.41 8.44
Carex spp. g/m2 0.44 3.52 4.92 4.20 5.52 2.16 + S.E. 0.35 2.34 2.33 2.73 3.40 1.48
DactyIi s glomerata g/m2 1.64 3.48 34.52 58.72 43.12 73.08 + S.E. 0.79 2.10 22.82 37.04 28.25 22.68
Soli dago juncea g/m2 0.08 2.36 0.24 9.52 3.72 11.32 ± S.E. 0.05 1.17 9.18
PhIeum pratense g/m2 0.01 12.00 2.00 12.52 + S.E. 6.85 1 I .31 141
Table 34. (Continued).
COLLECTION DATE
4/7 5/7 6/24 8/14 9/11 10/21
Number of Subsamples 16 15 12 12 12 12
Aster ericoldes g/m2 0.16 1.20 8.24 3.00 ± S.E. 5.26 2.04
AchiI lea mi Ilefolium g/m2 0.04 1.48 0.04 0.08 1.92 ± S.E.
Physalis subgIabrata g/m2 0.12 6.92 ___ ± S.E.
Setar1 a gIauco g/m2 0.030.12 __ ± S.E.
Apocynum sp g/in2 0.76 ______± S.E.
Erlgeron philadelohicus g/m2 0.32 3.48 __ __ + S.E. 0.20 3.37
Lycopus sp. g/rn2 1.40 ______± S.E.
Prune I I a vuIgaris n /m2 1,28 142
Table 35. Frequency of occurrence and percent frequency of occurrence of herbaceous vegetation, Urbana Study Area, 1969. Data presented in the following sequence: frequency of occurrence (percent frequency of occurrence).
Seasona1 Date 4/7 5/7 6/24 8/14 9/11 10/21 Mean
No. Quadrats 16 15 12 12 12 12 79
Pasti naca sati va 1(6) 12(80) 8(67) 10(83) 8(67) 7(58) 46(56)
Poa spp. 14(88) 14(93) 8(67) 1 1(92) 10(83) 9(75) 66(84)
Daucus carota 3(19) 10(67) 6(50) 5(42) 9(75) 6(50) 39(49)
Agropyron repens 9(56) 7(47) 6(50) 7(58) 6(50) 6(50) 41(52)
Dacty1i s glomerata 6(38) 5(33) 5(42) 4(33) 5(42) 7(58) 32(41)
Soli daao juncea 2( 13) 7(47) 1(8) 3(25) 1(8) 1(8) 15(19)
Carex spp. 3(19) 6(40) 4(33) 3(25) 6(50) 4(33) 26(33)
Ph leurn pratense 1 (6) 5(33) 1(8) 3(25) 10( 13)
Ci rsi um arvense 2(13) 7(58) 3(25) 3(25) 15( 19)
Ci rsi um d i scolor 1(7) 3(25) 2( 17) 2( 17) 8(10)
Plantago lanceolata 1(7) 1(8) 4(33) 2C17) 8( 10)
Aster erlcoides 1 (8) 4(33) 4(33) 9(1 1 )
Aster sp. 1(8) 4(33) 2(17) 7(10)
Oxa1i s europaea 3(25) 4(33) 2(17) 9(1 1) 143
Table 35. (Continued).
3 6 2 5 0 0 3 ( Date 4/7 5/7 6/24 8/14 9/11 10/21 Mean
No. Quadrats 16 15 12 12 12 12 79
Er ? geron phi ladelphicus 5(42) 3C25) 8 ( 10)
Ambro5 i a arteini si i f o t j a 2(17) 1( 8 ) 3(4)
Taraxacum o ff i ci na ie 1(7) 1(8) 1( 8 ) 3(4)
Ach i iIea mi tle fo Ii um I (6) 2(17) 1(8) 2(17) 1(8) 7(9)
Leonurus cardi aca 1( 6 ) 1( 1)
T rifo li um 1( 8) I (8) 2(3) spp.
PhysaIi 5 1( 8 ) 1( 8 ) 2(3) longi fol ia
Claytoni a I (7) 1( 1) vi rginica
GaIium sp. t (7) 1( 1)
Brassica sp. >1(7) I d )
Li nari a vuIgaris 1( 8 ) 1( 1)
P otent!1 I a recta 1( 8) I (8) 2(3)
Lactuca sp. 2(17) 2(3)
Lycopus 1( 8 ) 1( 1) sp.
Setari a q Iauca 1( 8) 1( 8) 2 (3 ) 144
Table 35. (Continued).
SeasonaI 4/7 5/7 6/24 8/14 9/11 10/21 MeanDate
No. Quadrats 16 15 12 12 12 12 79
Prune I la vuI gar i s i(8) id )
Apocynum cannab i num I(8) 1(1)
PIantago major 1(8) Kl)
Nepeta catari a 2(17) 2(3)
Lys irnach i a quadri folia 1( 8 ) 1( 1)
Rumex crispu; 1( 8 ) 1( 1) 145
A Ir Samp Iing Data
Six, 24-hr samples were collected on the study area between
August II and August 27, 1969, to determine the possible loss of DDT to
the atomosphere by vaporization or codistillation. Each 24-hr sample
X 'T represented an a ir volume of 40.8 m (1440 f t J) , No DDT was detected
in the a ir samples. CIimatologicaI data collected in association with
the six a ir samples are given in Table 36.
Calorimetry Data - The number of calories per gram dry weight, the
percent water loss, and the number of calories per gram live weight
(wet weight) for the muscle tissue of the short-tailed shrew and the whole bodies of selected invertebrate species are given in Table 37.
Gas Chromatography Data
The pre-appticat ion residue levels of DDT and DDT metabolites detected in the gas chromatograph analyses of Blarina and Sorex collected from the study area during 1968 are given in Table 38. The sample preparation efficiency was 50%. Table 36. ClimatologicaI data collected in association with a ir samples, Urbana Study Area, 1969.
Date of Sample 1 nitiation 8/1 1 8/12 3/13 8/15 8/20 8/26
Sample In itia tio n Time 12:45 PM 1:30 PM 2:15 PM 1:52 PM 1:38 PM 11:18 PM
Average Wind Speed Cmph) 1.20 1 .31 2.07 1 .89 3.22 2.35
Wind Direction NW SE SE SW NE N
Maximum 24-Hour Temperature C°F) 76° 80° 83° 80° 72° 78°
Minimum 24-Hour Temperature C°F) 48° 52° — 66° 40° 40°
Re 1 atime Humidity at Beginning of Sampling Period 62 % 51% 60% 62% 60% 10%
Relative Humidity at End of Sampling Period 57 % 62 % 59% 74% 52% 54% 147
Table 37. Caloric values for the muscle tissue of the short-tailed shrew (Blarina brevicauda? and the whole bodies of selected invertebrate species.
Spec ies cal/q dry wt Per Cent Water Loss ca 1 /g X t S.E. X + S.E. 1 ive wt (Number of Subsamples) (Number of Subsamples)
Blarina brevicauda tSkeletal Muscle) 5197.4 ± 34.8 71.6 + 0.4 1476.1 (.4) (.4)
Melanoplus femur-rubrum 5458.9 ± 29.5 63.4 ± 1.6 1998.0 (4) C6)
Hadrobunus sp. 5362.1 ± 74.9 71.0 ± 3.6 1555.0 C3) (6)
Deroceras sp. 4951.2 ± 18.6 68.9a 1539.8 (2)
Gry11 us pennsyIvanicus 5360.3 ± 9.2 63.7^ 1945.8 (.3)
Parajulus sp. 3309.0 + 18.1 63.7b 1201.2 (4)
cl One water loss determination was made utilizing 93 individuals.
b Per cent water loss was not determined; the mean per cent water loss for the above arthropod species was substituted. 148
Table 38. Pre-appIication DDT residue levels In the short-tailed shrevi (8 larina brevicauda) and the masked shrew (.Sorex cinereus) collected on the Urbana Study Area, 1969.
Species and Total body residue level s (ppm 1ive wei ght) DDT metabolite in individual subsamples Cn = 4)a
1 2 3 4
Blarina
p,p’ - DDT 0.0257 0.0091 0.0193 0.1241 p,p’ - DDD NDb ND 0.0997 0.1983 p,p' - DDE 0.0345 0.0070 0.0358 0.0950 o,p - DDT 0.0232 0.0078 ND 0.0524 o,p - DDD ND ND ND ND o,p - DDE 0.0325 0.0319 0.0926 0.2847
Total residue level of DDT and metabolites (ppm) 0.1159 0.0558 0.2474 0.2178
So rex
p,pf - DDT ND 0.0268 0.0250 0.0132 p ,p’ - DDD ND 0.0091 ND ND p,p’ - DDE 0.0063 0.0033 0.0023 0.0226 o ,p - DDT 0.0143 0.0552 0.0931 0.0492 o,p - DDD ND ND ND ND o,p - DDE 0.0755 0.0459 0.0362 0.0730
Total residue level of DDT and metabolites (.ppm) 0.0961 0. 1403 0.1566 0.1580
Mean to ta l body residue levels of DDT and metabol ites (X ppm ± S.E.) B1 ari na 0.1593 + 0.0445
So rex 0.1378 t 0.0144
aSkin excluded from analysis
^ND Metabolite not detected. DISCUSSION
The conditions existing on the Urbana o ld -fie ld study area tended to simulate those conditions that would be present on a similar area one or more years afte r a spray application of DDT. The chief charac t e r is tic shared In common by the study area and the hypothetical site is the localization of the bulk of the DDT in the detritus stratum of the old-field. In a spray application, a sizable portion of the DDT would be intercepted and retained by the cuticular surfaces of the upper stratum of vegetation, although some of the insecticide would reach the detritus directly. The DDT retained in the herbaceous vegetation would be transferred to the detritus following the growing season. Even though the insecticide in the herbaceous vegetation might be diverted by feeding herbivores and transferred to higher trophic levels, u lti mately the DDT would be returned to the detritus stratum. As a conse quence, the primary steps In the translocation of the DDT to the remainder of the system must begin with the detritus reservoir.
DDT Contamination of Plants
The movement of DDT away from the detritus reservo Ir may involve the vegetation. Although certain limitations may have been placed on the 1969 vegetation residue data resulting from variations in the 1968 vegetation background radiation levels, most of the 1969 vegetation residue data is assumed to be valid. According to Caro
C1969), the organochI orine insecticides may be accumulated by plants by three possible mechanisms: I) the insecticide may be translocated
149 150
through the roots t o the remainder of the plant, 2 ) the insecticide may vaporize from the soiJ and condense on the aerial portions of the plant, and 3) the insecticide may he transported mechanically onto the plant surfaces by wind, rain splash, and direct contact. Mechanical contamination by the impregnated granules during the application was most likely responsible for the residues or deposits of DDT detected in Agropyron and AchiI lea collected at 6 days post-application. However, translocation or vaporization is believed responsible for the residues at all later collection intervals. The plant samples were taken from newly synthesized tissues during periods of rapid growth so it is unlikely that mechanical contamination was responsible for residues found during the later collection intervals.
Although the transIocation of organochlorine insecticides through the vascular tissue is possible, the magnitude of translocation involved is dependent upon the aqueous s o lu b ility of the compound in question (Caro, 1969). Since DDT has an extremely low s o lu b ility in water, translocation probably played only a minor role in mobilizing the insecticide from the detritus. A similar conclusion was reached by
Ware et al. (1970) in a study of transIocation of carbon-14 labeled DDT from the soil to the tissues of a lfa lfa (Medicago sativa) . Therefore, vaporization appears to be the most probable method of DDT accumulation by plants, although negative results were obtained from the series of
24-hr a ir samples. The DDT detected in the plant leaves is believed to have resulted from the condensation of the vaporized insecticide on the pi ant surfaces. The DDT residues detected in the roots of Daucus carota could have resulted from either absorption or mechanical contamination 151
due to the close association of this plant structure with the contaminated soil and detritus.
The absence of DDT in the a ir samples may be attributed to the low concentration of the insecticide available for sampling and to the high dilution factor involved. The possible association of DDT vapor ization with localized microclimatic conditions and the central location of the sampling apparatus on the study area could have resulted in a dilution of the DDT below detectable levels. Another factor was the collecting liquid, hexylene glycol. This compound represents, at best, a compromise between a compound with high DDT s o lu b ility and one with low v o la t ility . The ideal compound having both characteristics is unavailable.
DDT Concentration by Invertebrates
The detritus-inhabiting invertebrate organisms are apparently the chief means by which DDT is translocated from the detritus to the vertebrate components in an o ld -fie ld ecosystem. The invertebrate functioning most conspicuously in this capacity on the Urbana site was the slug Deroceras sp. which carried a mean residue level of 18.89 ppm
DDT (range: 16.58 ppm to 20.67 ppm) during the course of the growing season. The a b ility of the members of this genus and slugs in general to concentrate DDT to levels well above those in the environment with out displaying the toxic effects of the insecticide has been reported by several investigators. Gish C19701 reported a maximum DDT residue level of 52.70 ppm in Deroceras sp. and Li max sp. (genera combined in 152 residue analyses), a concentration 17.93 times higher than the DDT levels
In the slugs' environment. The slug Aqriolimax reticulatus was reported by Davis and French (1969) to carry residue levels of 40.10 ppm DDT,
2.33 times higher than environmental insecticide levels. A sim ilar concentration factor was given by Davis (1968) for the slug Arion sp.
The two crickets Nemob j us and GryI I us, the phalangid Hadrobunus and the millipede Parajulus also function as important cyclers of DDT from the detritus. All of these organisms either feed upon the detritus d ire c tly or prey upon detritus-feeding organisms. However, the quantity of the insecticide concentrated by these organisms is much lower than ■ that concentrated by Deroceras.
Small Mammal DDT Storage Patterns
The relationship between exposure time and the to ta l body residue levels of DDT is depicted in Fig. 10 for Sorex and Microtus‘and Fig. 11 fo r B Iarina. The curves depicting the relationship for Sorex and
Microtus are characterized by rapid DDT accumulation during the firs t month post-application followed by decreasing and stationary levels of storage during the latter half of the growing season. In contrast, the
Blarina curve shows a steady increase in DDT storage throughout the growing season. The DDT storage patterns observed in Sorex and
Microtus may possibly be attributed to either or both of the following factors: I) the attainment of an equilibrium between the levels of DDT
Intake and elimination, or 2) a change in the population age structure and exposure time. 153
0.2 MICROTUS PPM DDT
20 40 60 80 100 120 DAYS POST-APPLICATION
2.0
SOREX
PPM DDT
20 40 60 80 100 120
DAYS POST-APPLICATION
Figure 10. DDT storage patterns In the meadow vole'(Microtus Pennsylvania) and the masked shrew (Sorex clnereus) durtng the 1969 growing season. 154
14
1 3
12
1 1
1 0
9
PPM 8 DDT 7
6
5 BLARINA
4
3
2
1
20 40 60 80 100 120 DAYS POST-APPLICATION
Fig. I I. DDT storage pattern In the short tailed shrew (Blarina brevicauda) during the 1969 growing season. 155
A mammal exposed to an Insecticide at a set dosage level w ill ultim ately undergo a physiological adjustment to the Insecticide resulting in the establishment of an equilibrium between the levels of storage and excretion (Hayes, 1965). If the level of insecticide intake remains constant, the level of insecticide storage in the tissues w ill remain constant. Such an equilibrium condition could have been responsible for the storage patterns in Sorex and Microtus. The decrease in storage occurring in Sorex a fte r the f ir s t month could have been the result of a physiological adjustment of the shrew to the insecticide levels contained in the prey. The initial increase in the storage rate in Sorex may also be attributed to feeding on DDT-kilied invertebrates immediately following the application. A diet of this type would have led to a sharp but short-iived increase in the dietary intake and storage of the insecticide. Microtus, like Sorex, could also have undergone a physiological adjustment which resulted in the establishment of an equilibrium between the rates of DDT intake and eIi mi nation.
The total body residue levels in Blar?na displayed a significant
CP 0.05) positive linear relationship with increasing time. A storage pattern of this type could be attributed to either I) the absence of stationary levels of DDT intake due to increasing DDT storage in the prey species, or 2) the capacity of Blarina fo r accumulating relatively high DDT levels before attaining an equilibrium with the dietary intake. The first alternative seems less tenable as an explanation fo r the observed storage pattern. They prey species probably attained an equilibrium with the DDT levels in the environment within a 156
relatively short time. The limited invertebrate residue data indicate that most potential prey species attained maximum residue I eye is within the f i r s t month of exposure.
Dindal and Wurzinger (1971) found that the te rre s tria l snail
Cepaea hortensis under laboratory conditions reached a storage equilibrium with dietary levels of chlorine-36 labeled DDT w ithin a
24-hr period. If this rapid attainment of equilibrium levels is characteristic of gastropods in general, the slug Deroceras could have achieved an equilibrium soon a fte r exposure to the insecticide.
Deroceras has previously been reported as a probable Blarlna food item.
(Ingram, 1942) and is believed to have been a major prey species of this shrew on the Urbana site. The most likely explanation for the
increase In Blarina residue levels throughout the growing season would simply be that th is species tends to accumulate greater quantities of
DDT before a storage equilibrium Is reached with the dietary intake.
A change in the population age structure could have been partially
responsible for the pattern of DDT storage observed in Sorex and
Microtus. The increase in DDT storage evident during the firs t month could be attributed to increasing exposure time among a population of
Individuals of similar age. All or most of the individuals composing the population during the firs t month post-application were present on the study area at the time of application. As new individuals were added to the population through reproduction during the course of the summer, the number of individuals with shorter exposure time increased.
Since the animals were collected at random from the study area and no method of aging was available, the likelihood of younger individuals 157 appearing in each collection increased as the population of older
individuals was. diluted with Youn9er individuals.
The residue data for each species population is believed to reflect the actual level of insecticide accumulation in the population since i t re fle cts the prevailing age structure and exposure time. Over a period of a year, DDT accumulation in a population of a short-lived species could vary depending upon the age structure and exposure time ✓ of the population at the time the population is sampled. Such variations would occur in the absence of variations in DDT intake.
Summer and fa ll residue levels would be low because of the higher proportion of young individuals in the population and a lower average exposure time; residue levels during the winter and early spring would be higher due to the higher proportion of older individuals in the population and a higher exposure time for the population.
Blarina failed to display the possible effects of changing age structure on the pattern of DDT storage. However, the age structure
in the Blari na population obviously should have changed in favor of younger individuals. Pearson Cl945) suggested that the old individuals in a Blari na population may be diluted to a level of 10^ by August or
September. Both Sorex and BIari na experienced a high level of mortality associated with trapping. Live individuals were normally released to conserve limited populations for future collections. This collecting procedure may have biased the Blarina collections in favor of older individuals and higher residue levels. 158
Ecosystem Comparison of Small Mammal Residue Data
The DDT residue levels occurring in shrews and rodents collected
in the DDT-sprayed forestland of northern Maine were given by Dimond and
Sherburne (1969). Although a ll collection areas were in it ia lly sprayed with DDT at a rate of 0.89 kg/ha (I lb/acre), the shrews and rodents were collected from areas with varied spray history so as to provide a 9-year continuum of residue data. Unfortunateiy> these authors present the'ir data only as mean total body residue levels for categories of shrews and rodents. Since no data are given fo r individual species, absolute com parisons can not be made between the Maine residue data and the Urbana residue data. Nevertheless, a comparison of the data Is instructive from the standpoint of DDT accumulation in d iffe re n t ecosystems.
The shrews (Blari na brevi cauda and Mi crosorex hoyi) and rodents
CCIethrionomvs qapperj and Peromyscus sp.) from the Maine study site carried mean total body residue levels during the year of application of 15.58 ppm and 1.06 ppm, respectively. The two species of shrews and
Microtus from the Urbana study site had lower mean total body residue levels of 4.23 ppm and 0.10 ppm, respectively. However the residue lev els detected in the shrews and rodents collected on the Maine site averaged 1.53 ppm and 0.07 ppm, respectively, a fte r the f i r s t year. The la tte r data more closely approximate the data obtained for the Urbana small mammals. The higher residue levels detected in the Maine small mammals during the firs t year apparently resulted from the application of the insecticide in the form of a spray. Feeding by shrews on insect- icide-killed invertebrates and by rodents on contaminated plant material 159
most likely was responsible for the higher residue Ieye Is. During the
second year and thereafter, DDT entering the food web originated from
the d etritu s layer. Since th is is the condition simulated on the
Urbana s ite , a greater s im ila rity exists between the Urbana small
mammal residue levels and those levels detected in the Maine small
mammals after the firs t year.
I
DDT Accumulation in Shrews
The total body residue levels of DDT Cexpressed as rriicrograms
of DDT per gram of body weight) were conspicuously higher in BIarina
than in Sorex. This difference is due in part to the absence of
residue data for the skin in the total body residue data given for
Sorex. Data for th is tissue were included in the Blarina total residue
data. However, when the skin residue levels are excluded from the
Blarina to ta l residue data and the data then compared with the Sorex
total residue data using a paired t-fest (Schefler, 1969), the data
for the two species were significantly different (P< 0.05). A t-
vaIue calculated from the data fe ll ju s t short of the c ritic a l value
(3.131<3.143; df = 6) when tested at the 0.01 level.
The difference in total body residue levels observed between the two species may reflect I) a niche segregation mechanism involving
a difference in the prey size taken by each species and a resulting
difference in the levels of DDT ingested, or 2) physiological differences.
Getz (.1961), studying the factors influencing the distribution of
Sorex cinereus and Blarina in southern Michigan, stated that inter 160 specific competition was not a factor influencing the distribution of these two species. Based upon the correlation of the distribution of
Blarina with the distribution of larger invertebrate species and the
lack of such a correlation for Sorex, he concluded that the two species utilize different size prey species. Sorex was thought to feed primarily on collembolans, ants and spiders.
An exact identification of the prey composing the diet of a" shrew based on stomach content analysis is d ifficu lt due to the finely divided condition of the ingested food items. In the few published reports on shrew diets based on stomach content analysis, rarely are the organisms composing the diet categorized beyond the levef of class or order. Hamilton (1930) gave the following dietary composition by per cent occurrence for Sorex cinoreus and BIari na, respectively: insects, 65.3$ and 47.8$; vertebrates, 7.1$ and 4.0$; centipedes, 6.8$ and 3.8$; annelids, 4.3$ and 7.2$; mollusks, 1.2$ and 5.4$; vegetation,
1,1$ and 11.4$; arachnids, 0.9$ and 2.0$. Food items recorded for
Blarina but not for Sorex were miltipeds, 1.7$ and crustaceans, 6.7$.
Among the insects occurring in the stomach contents of Sorex cinereus,
Hamilton listed the following orders: Coleoptera, Diptera, Lepidoptera,
Hymenoptera, and Orthoptera. Whitaker and Ferraro (1963) reported the occurrence of approximately the same prey groups in the stomach contents of summer-collected Blarina in Hew York. Buckner (1964) in an investigation of shrew predation on larch sawflies (Pristiphora erichsonii) in Manitoba found insects composing a larger portion of the die t of Sorex than of B larina. Although the Blarina stomachs contained fewer sawflies, more adult sawflies than larvae were found 161
In the stomach contents of Blari na.
The data provided by Getz Cl9613 and Buckner Cl964). suggest that a certain amount of niche segregation based on prey size does occur between Sorex and Blarina. The difference in accumulation patterns discussed above also suggests that d iffe re n t prey types or sizes may be taken by each species of shrew. Although the food data given by
Hamilton (1930) and Whitaker and Ferraro (1963) indicate that both shrew species feed w ithin the same larger taxonomic unit, prey selection on the basis of size within a taxonomic unit also seems possible. However, it also appears likely that a considerable amount of overlap in prey could occur, especially among prey species of inter mediate size. In the la tte r prey category, feeding by both shrew species'is probably a matter of opportunism with the diet composition being subject to variations according to seasonal prey abundance.
The metabolic data given by Buckner (1964) for Sorex cinereus and Blarina were used to obtain an estimate of the daily energy demands of each species. Using the mean body weights for the Urbana collected animals, the daily energy requirements (standard metabolic rate) for
Blarina were 8.38 kcaI per day and for Sorex 6.05 kcal per day. When a correction was made for the specific dynamic, or calorigenic, effect of dietary protein using the urinary nitrogen data given by Buckner (1964), the energy requirements of BIari na and Sorex were 5.64 kcal per day and 4.20 kcal per day, respectively. Placed on a gram basis the energy requirements of Blarina and Sorex were 0.35 kcal per gram per day and
1.22 kcal per gram per day, respectively. The energy requirement, or metabolic rate, increases with decreasing body size. If the assumption 162 is made that the diet of the two species is essentially the same, DDT accumulation in Sorex shouId be higher than that in Blarina.
To demonstrate the la tte r point, the quantity of DDT consumed per day by each species on a diet consisting solely of the siug Deroceras was calculated using the daily energy requirements of each species of shrew, the mean residue level fo r Deroceras, and the caloric value for
Deroceras (Table 37). Blari na wouid consume 4.35 pg of DDT per gram per day whereas Sorex wouId consume 15.44 pg of DDT per gram per day.
Sorex wouId therefore consume 3,54 times more DDT than BIarina per gram of body weight.
Sim ilar comparisons were made between the two species of shrews on separate diets of GryI I us, Me Ianop]us, Hadrobunus, and ParajuI us based on caloric values from Table 37 and the mean residue levels for each prey species. The quantity of DDT consumed by each predator on each prey diet is summarized in Table 39.
No clear-cut explanation for the observed difference in the levels of DDT accumulated by Sorex and Blarina is avai lable. Some degree of feeding according to prey size probably exists in each species. This would lead to the assumption that dietary differences could result in the observed differences in residue levels. However, some overlap in prey size selection probably also occurs. This view of DDT intake may be further complicated by either the ability of Sorex to metabolize and eliminate DDT at a faster rate than Blarina or the tendency of BIari na to absorb higher levels of DDT from the diet. Without a more intensive study of the phenomenon under controlled laboratory conditions, the only explanation possible would be that a number of factors are 163
interacting to produce the difference in accumulation rates.
Table 39. Summary of the probable levels of DDT consumed per gram of body weight by the short-tailed shrew (Blarina brevicauda) and the masked shrew (Sorex cinereus) on diffe re nt prey diets.
Prey Species
Gry11 us Me 1anop1 us Hadrobunus Paraju1 us
Blari na
Micrograms DDT consumed per gram of body weight 0.14 0.02 0.24 1.17
Sorex
Micrograms DDT consumed per gram of body weight 0.47 0.07 0.81 4.97
Ratio of micrograms DDT consumed by shrews (Sorex: Blarina) per gram of body weight 3.3 : 1 3.7 : 1 3.4 : 1 4.3 : 1
Blarina Home Range and Tissue DDT Levels
An attempt was made to determine if a discernible relationship existed between the levels of DDT within the home range of BIari na brevicauda and the levels of DDT stored in the tissues. The tissues tested were the live r and the skeletal muscle, two tissues in which consistently high DDT residue levels were detected during the course of the study. The level of DDT within an individual animal's home
range was based on the levels and distribution of chlortne-36 labeled
DDT indicated by the d istrib u tio n survey taken on June 10. 164
The investigation of the above relationship was hindered by
limited knowledge concerning the size and shape of the shrew's home
range. The mean home range size for the Blarina inhabiting the study
area is unknown. Earlier attempts to acquire such information were
discontinued when trapping and marking operations produced high levels
of mortality. Therefore, the home range size used here (0.45 ha, or
I.I I acres) represents a synthesis of the home range data given for this
species by Blair (1940, 1941) and Buckner (1957). Although information
concerning home range shape is unavailable, a circu la r home range with
a diameter of 23.9 m (the diameter of a 0.45-ha area) was used. The
point of capture (grid station) was arbitrarily used as the home range
center. The mean levels of chlorine-36 radioactivity (dpm) and DDT
concentration (rnicrograms) occurring within the home range were
derived by plotting the circular home range on the scale map of the
study area DDT distribution pattern. The mean radioactivity and DDT
levels for each animal’s home range and the correspond!ng tissue residue
levels are given in Table 40. A comparison of the home range radio
a c tiv ity and DDT levels (ranked in order of decreasing magnitude) and
the tissue residue levels is contained in Table 41.
No apparent positive relationship was evident between home range
levels and tissue storage levels of DDT. In fact, a negative relation
ship occurred in the shrews collected at 17 and 29 days post-application.
The residue levels in the live r at 17 days and in both the liv e r and skeletal muscle at 29 days were highest in those animals captured from home ranges having the lowest DDT levels; tissue residue levels were
lowest in those animals having the highest home range DDT levels. No 165
Table 40. Mean radial'ion and DDT levels w ithin the home range and DDT residue levels in the liver and the skeletal muscle of 24 individual sh o rt-ta ile d shrews (Blarina brevicauda), Urbana Study- Area, 1969.
Days Post-Applica [•lean Radiation (dpm) DDT Residue Levels tion and Capture and DDT Levels ( pg ) in Tissues (ppm) Gri dsa of 1ndivi d- within Home Range ual Shrews dpm pg Livor Skeletal Muscle
17 Days 11-6 3404 455 4.40 3.69 F-6 2487 329 3.76 8.62 A- 1 1251 165 1 .46 0.67 B-l 961 127 1 1 .99 1 4.95
21 Days 1-5 6875 910 33. 14 19.43 B-2 4607 641 4. 13 1 .18 B-l 964 128 1.15 28.35 F-7 578 77 2,54 0.48
29 Days 1-5 4875 645 0.00 0.40 H-7 2683 355 4.93 2.48 F-8 2203 290 7.73 14.51 C-5 1854 245 8.20 42.44
60 Days A-4 3314 440 95.42 73.54 J-6 2557 338 10.98 14.22 G-6 2403 318 147.27 33.65 B- 10 2158 285 6. 1 1 3.07
91 Days C-8 3747 496 8.02 1 1.55 D-4 2556 338 51 .41 31 .84 1-7 850 1 12 12.87 5.86 G-7 384 51 24.74 13.91
126 Days B-3 4404 583 70.60 37.80 E-4 3883 514 17.87 19.61 F-6 2487 329 52.35 19.91 B-7 1914 253 69.76 22.40
3 Grids arranged in order of decreasing ra dio a ctivity levels. 166
Table 41. Relationship between home range ra d io a ctivity, home range DDT levels, and DDT residue levels in the liver and the skeletal muscle of the sh o rt-ta ile d shrew (Blarina brevicauda), Urbana Study Area, 1969.
Days Post- Decreasing Order of Grid Decreasing Order of App1icat ion Radioactivity and DDT Levels Tissue Residue Levels
17 H-6 F-6 A -1 B-l Skeletal Muscle: 4 3 2 1 B -1 F-6 A -1 H-6 1 3 2 4
Liver: B-l A -1 F-6 H-6 1 2 3 4
21 1-5 B-2 B-l F-7 Skeletal Muscle: 4 3 2 1 B-l 1-5 8-2 F-7 2 4 3 1
Liver: B-l 1-5 B-2 F-7 2 4 3 1
29 1-5 H-7 F-8 C-5 Skeletal Muscle: 4 3 2 1 C-5 F-8 H-7 1-5 1 2 3 4
Liver: C-5 F-8 H-7 1-5 1 2 3 4a
60 A-4 J-6 G-6 B -10 Skeletal Muscle: 4 3 2 1 A-4 G-6 J-6 B-10 4 2 3 I
Liver: G-6 A-4 J-6 B-10 2 4 3 1
90 C-8 D-4 1-7 G-7 Skeletal Muscle: 4 3 2 1 D-4 G-7 C-8 1-7 3 1 4 2
L ive r: D-4 G-7 1-7 C-8 3 1 2 4 167
Table 41. (Continued).
Days Post - Decreasing Order of Grid Decreasing Order of App1i cat ion Radioactivity and DDT Levels Tissue Residue Levels
126 B-3 E-4 F-6 B-7 Skeletal Muscle: 4 3 2 1 B-3 B-7 F-6 E-4 4 1 2 3
Liver: B-3 B-7 F-6 E-4 4 1 2 3
dNo DDT detected in the liver of the shrew trapped at grid 1-5.
discernible relationship was evident from the rankings of the animals collected at 21, 60, 91, and 126 days. Apparently, the limitations created by inadequate knowledge of home range size and shape and the variables introduced by sex and age differences among animals within a given collection would tend to mask any relationship between home range
DDT levels and tissue residue levels. The only conclusion that can be reached concerning the above exercise is that no relationship was detectable.
Qld-Field DDT CompartmentaIization
An overall view of DDT accumulation and translocation at the ecosystem level will now be attempted through the estimation of the quantities of the insecticide compartmentalized in the major old-field ecosystem components. Each, component estimate was derived u tiliz in g biomass and density estimates obtained either from the present study or 168
from the literature. The bulk of the density estimates were taken from
the literature, so the component estimates for Urbana are considered
approximations of true values. Nevertheless, the selection of density
data for species, geographic, and ecosystem compatibility (where possible)
is believed to have produced estimates of sufficient accuracy to reflect
the re la tiv e magnitude of DDT associated with each component. The
compartmentaIization estimate for each component and the procedure by
which the estimate was derived are given below.
Detritus - Based upon the formulation and efficiency estimate of 66.18$,
3005.57 g of DDT were in it ia lly introduced into the detritus compartment
of the old-field system.
DDT Loss in Run-off - A mean of 2.77 ng of DDT per lite r was present
between 6 and 15 days post-application in the water of the 0.17-ha
(0.41-acre) pond receiving drainage from the study area. Since the exact morphometry of the pond was unknown, calculation of the water
volume was made on the basis of an acre-foot of water and the resulting
volume calculation (17,856 ft-5! converted to liters (506,351.6 liters).
This volume is believed to be a close approximation of the true volume
since the pond was relatively shallow and accessible in most areas by
wading (the maximum depth in deepest portion was approximately 1.6 m,
or 5 ft). Therefore, the quantity of DDT calculated to have been carried
into the pond from the 4.05-ha study area through run-off was 1402.59
ug.
Herbaceous Vegetation -.An estimate was made of DDT compartmentaIization
in the aerial portions of the study area herbaceous vegetation based on 169 the residue levels occurring in individual species during periods of peak biomass production. The DDT residues are assumed to have reached the foliage through condensation of the vaporized insecticide. This estimate is considered to be a rough approximation of the DDT bound to the cu ticu la r surfaces of the vegetation due to I) the re la tive ly high standard error associated with both the residue and biomass data, 2) the inability of the biomass sampling scheme to accurately estimate the biomass of species having low frequencies of occurrence, and 3) the fact that not a i r of the 96 plant species were analyzed for DDT. Nevertheless, the 13 species which were analyzed fo r DDT accounted for 91.8# of the t total vegetation biomass.
Three of the 13 species, Dactyl is olomerata, Phleum pratense and
Plantago lanceolata, contained no detectable DDT and represented 23.3# of the to ta l biomass. Two additional species, Vernonia noveboracensis and Soli dago juncea, were not included in the estimate due to question able biomass and residue data. The Vernonia was excluded because the frequency of occurrence was too low to be measured by the biomass sampling procedure. DDT residues in Solidago were detected only at 16 days post application. Because of the isolated nature of the data, the latter species was not used in the calculation of the estimate. Ci rsi urn arvense and £. discolor were combined in the biomass estimation procedure due to the difficulty experienced in distinguishing seedlings of these two species during the early growing season. Only C. arvense was analyzed fo r DDT. However, the biomass data were used in the estimation of DDT compartmenta I i zati on based on the observation that C_. arvense was the more common of the two species and represented the major portion of 170
the biomass recorded for the genus.
Therefore, based on the residue levels occurring at the periods
of peak biomass production in Aster ericoides, Poa spp., Aqropyron
repens, Daucus carota, Ach i I 1 ea mi I I efo I turn, Past i naca sati va, Er iqeron
philadelphicus, and Crisium arvense (66.4$ of the tota l biomass), 53.57 g
of DDT were estimated to have been compartmentalized in 91.8$ of the
study area herbaceous vegetation. Since the biomass v/as in it ia lly
determined on a dry weight basis, the conversion of dry weight data to
wet weight data (so as to be compatible with the wet weight residue data)
was made on the assumption that the vegetation while drying underwent
a 70$ reduction in weight due to water loss. The DDT content of
individual species extrapolated to the total species peak biomass on
the 4.05-ha study area is given in Table 42.
Invertebrate DDT CompartmentaIization - The quantity of DDT compartment
alized in the major invertebrate species populations was estimated using
published population data for each species or for a closely related spe
cies. Biomass data were derived in the present study; residue data
were correlated as closely as possible with peaks in population density
and biomass.
Red-legged grasshopper - The study conducted by Wiegert (1965) in a
southeastern Michigan oid-field community was used as the source of
population density data fo r the red-legged grasshopper (Me IanopI us
femur-rubrum). The population density given by Wiegert for late
September and early October was 0.32 individual per C2-year average).
The mean weight for individuals collected on the Urbana site in September Table 42. Estimate of DDT compartmentaIization in the study area herbaceous vegetation (aerial portion) based on residue levels in individual species during the time of peak biomass.
Aster ericoides
X ppm DDT + S.E. 7.79 ± I .92 (92 days) X Biornass (grams dry wt + S.E./m^) 8.24 + 5.26 C9/II/69) Biomass (grams dry wt /4.Q5 ha) 33.37 X I o' 1 Biomass (grams wet wt/4.05 ha) 111.23 X I04 Grams DDT in species population 8.67 Per cent of total vegetation biomass 1.8
Poa spp.
X ppm DDT + S.E. 1.66 dr 0.42 (62 days) X Biomass (grams dry wt + S.E./m^) 82.12 4* 22.87 (8/14/69) Biomass (grams dry wt/4.05 ha) 332.58 X I04 Biomass (grams wet wt/4.04 ha) 108.60 X I04 Grams DDT in species population 18.40 Per cent of total vegetation biomass 18.4
Agropyron repens
X ppm DDT + S.E. 0.29 4* 0. 19 (29 days) X Biomass (grams dry wt + S.E./m ) 116.76 + 50.25 (6/24/69) Biomass (grams dry wt/4.05 ha) 475.88 X I04 Biomass (grams wet wt/4.05 ha) 586.27 X Grams DDT in species population 4.60 Per cent of total vegetation biomass 2 6.1
Daucus carota
X ppm DDT + S.E. 4.22 + 0.59 (92 days) X Biomass (grams dry wt + S.E./m ) 35.40 + 15.93 (9/11/69) Biomass (grams dry wt/4.05 ha) 143.37 x ,01 Biomass (grams wet wt/4.05 ha) 477.9 x I04 Grams DDT in species population 20.17 Per cent of total vegetation biomass 7.9
AchiI lea mi Ilefolium
X ppm DDT + S.E. 1 .23 + 0.85 (23 day X Biomass (.grams dry wt/m^) 1 .48 (6/24/69) Biomass (grams dry w t/4.05 ha). 5.99 x !0 4 Biomass (grams wet wt/4.05 ha) 19.97 x I04 Grams DDT in species population 0.25 Per cent of total vegetation biomass 0.3 172
Table 42. (Continued).
Pastinaca sativa
X ppm DDT t S.E. 0.96 + 0.96 C23 days) X Biomass (grams dry wt + S.E./m ) 23.00 + 8.04 (6/24/69) Biomass (grams dry wt/4.05 ha) 14.09 X 104 Biomass (grams wet wt/4,05 ha) 46.96 X I04 Grams DDT in species population 0.45 Per cent of total vegetation biomass 9.4
Erigeron philadelphicus
^ ppm DDT + S.E. 1.43 + 1 .13 (62 days) X Biomass (grams dry wt + S.E./m^) 3.48 + 3.37 (8/14/69) Biomass (grams dry wt/4.05 ha) 14.09 X I04 Biomass (grams wet wt/4.05 ha) 46.97 X I04 Grams DDT in species population 0.67 Per cent of total vegetation biomass 0.8
C i rs i urn spp.
X ppm DDT + S.E. 0.56 + 0.33 (62 days) X Biornass (grams dry wt + S.E./m^) 4.72 + 3.08 (8/14/69) Biomass (grams dry wt/4.05 ha) 19. 12 X [01 Biomass (grams wet wt/4.05 ha) 63.73 X I04 Grams DDT in species population 0.36 Per cent of total vegetation biomass 1.7
Per cent of the total vegetation biomass represented by those species containing DDT residues (8 species) 66.4
Estimate of DDT contained in 9I.8£ of the study area vegetation based on the DDT detected in 8 of the 13 species analyzed. 53.57 g DDT 173
was 0.4393 g (.live weight); the total biomass for this species on the
4.05-ha study site was 5693.33 g. The DDT residue level detected during
October was 0.13 >jg/g. Therefore, the total 4.05-ha red-legged grass
hopper population was estimated to contain 740.13 pg, or 0.00074 g of
DDT.
Lesser fie ld cricket - The November density data given by Wolcott
(1937) for a central New York meadow-inhabiting population of Nemob i us
fasciatus (= N. a I Iard i according to Alexander and Thomas, 1959) was used
to estimate the size of the Urbana lesser field cricket (if. a I I ard i )
population. Based on this author's density estimate of 39.2 individuals
per 100 ft^ (4.2 individuals per m^), 170,755.20 lesser fie ld crickets
could have occurred on the study site. The mean weight for individuals
collected on the Urbana site during October was 0.0846 g; the population
biomass would, therefore, be 14,445.89 g. Since the tissues of this
species contained 2.07 jug/g DDT during October, the lesser field cricket
population would have contained 29,903 ,ug, or 0.0299 g DDT.
Greater field cricket - Wolcott (1937) reported the density of Gry1 I us
ass irnt I us occurring in meadow habitat as 16 individuals per 51 ft^
(3.4 individuals per m^). This density was used in estimating the size of the Urbana population of G. pennsyIvanicus as 136,757 individuals.
During October, the la tte r species had a mean weight of 0.3595 g
(wet weight), a residue level of 0,66 pg/g DDT, and an estimated total
population DDT content of 32,415.35 pg, or 0.0324 g.
Deroceras sp. - A Deroceras popuI at ion of 1,730,426 individuals was estimated to have occurred on the study area. This estimate v/as based on a November density given by Hunter (.1968b) in the United Kingdom
of 5364 Agrioljmax reticuiatus C= Deroceras re ticu ia tu s) per 1350 ft^
(.43 individuals per m^). The October individual biomass and estimated
population biomass on the Urbana area were 0.0560 g and 96,903.9 g,
respectively. In^pctober (121 days post-application), the DDT residue
level of 18.35 jjg/g was detected in the slug population. A total of
1.78 g DDT was, therefore, estimated to have been compartmentalized in
the slug population.
ParajuI us sp. - The density estimate given by Wolcott (1937) for the
meadow-inhabiting ju Ii form mi I Ii ped JuI us caeruleoci nctus was used in
estimating the size of the Paraj uI us population. The estimate for J uI us
7 7 of 762 individuals per 100 ft (82 individuals per m ) was projected to
give an estimated Parajulus population of 3,319,272 individuals per
4.05 ha. The October mean weight was 0.1288 g per individual and the
October residue level was 2.29 >ig/g. A total of 0.979 g DDT was estimated
to have been compartmentalized in the milliped population.
Hadrobunus sp. - The phalangid Hadrobunus sp. was assumed to occur in
August at a density of three individuals per m^ based on the data given
by Todd (1949) for the grass Iand-woodI and inhabiting Nemastoma lugubre.
Therefore, on 4.05 ha there occurred an estimated 121,500 individuals
having an August mean weight and DDT residue level of 0.1029 g and 0.54 pg/g, respectively. The total quantity of DDT estimated to have been
tied-up in the phalangid population was 6751.27 ^g, or 0.0067 g.
Vertebrate DDT CompartmentaIization - Although a rather large number of
vertebrate species occurred on the study area, only Microtus, Sorex, and 175
Blarina were considered with regard to DDT compartmentaIization. These three species were given special consideration because of the more extensive residue data accumulated fo r these animals during the study, their larger populations, and their special trophic positions.
Microtus population - Since no density data were available fo r the
Urbana M?crotus population, the Microtus population data given by Golley
(I960) in a study of energy flow in a central Michigan o ld -fie id community was u tiliz e d . Based on Golley's data for the period between late May and mid-October { a period approximating the interval during which residue data were collected on the Urbana study site), a population density of 13 Microtus per ha was obtained; 53 individuals would have been present on the 4.05-ha study area. The mean total body burden for individual Microtus based on a mean body weight of 32.9 g was 3.4 ug.
Therefore, in a hypothetical population of 53 Microtus there would be compartmentalized 180.5 ug of DDT. During the same May to October time interval, Gol ley's data yields a mean mortality rate of 3352. Based upon this m ortality rate, 18 Mi crotus and 61.2 ug of DDT v/ould be lost from the hypothetical population. The DDT associated wtth this segment of
"^e Mi crotus population could either be exported out of the system through avian and mammalian predation or ultimately returned through death and predation to the old-field detritus reservoir.
BI ari na population - The data provided by Townsend (.1935) and B la ir (1940) for old-field inhabiting BIarina populations were used to set the size of a hypothetical Blarina population for the Urbana study site. A mean population density of 19.3 individuals per acre was obtained from an average of 3 years' data given by Townsend fo r a study conducted in
central New York. Blair's 2 year study of Blarina populations in
southern Michigan produced a mean population density of 1.5 shrews per
acre. A mean population density of 10.4 shrews per acre was obtained
by combining the data of these two investigators; this density was used
for the Urbana hypothetical population. Therefore, 104,0 Blarina
were assigned to the 4.05-ha study area. The mean total body burden
of DDT fo r th is species was 112.62 ^ig as determined on the basis of a
mean body weight of 15.9 g. In a population of 104.0 Blari na, 11,712.5 pg of DDT would be compartmentalized. Pearson (1945) estimated the rate
of mortality in Blarina to be 20^ per month. This level of mortality
was also supported in a later study by Dapson (1968). Therefore, if
this rate of mortality is assumed to have occurred in the Urbana
population, 21 individuals and 2365.0 pg of DDT could be lost from the
popuI at i on.
Sorex population - The size of a hypothetical Sorex population which
could have occurred on the Urbana site was determined using the data of
Townsend (1935) and Bole (1939). Townsend and Bole found the maximum
densities for this species over 2-year periods in centra! New York and
Ohio to be 10.0 and 5.0 shrews per acre, respectively. Based on the data
of these two investigators, a mean population density of 8.0 shrews
per acre and a to tal population of 80.0 shrews were assigned to the
study area. The mean total body burden of DDT based on a mean body
weight of 3.34 g was 3.05pg. The total Sorex population of 80.0
individuals, therefore, contained 244.0 jug of DDT, or 244.0 x 10 ^ g of 177
DDT. In the absence of published mortality rates for this species, the
20/J m o rta lity rate given fo r Blarina by Pearson C19453 and Dapson CI968)
was used to visualize the loss of individuals and DDT from the Sorex
population. Therefore, this mortality rate would permit a loss of 16
individuals and 48.8 jug of DDT.
The estimates of DDT compartmentaIization presented here are at best
crude and minimal measures since they are based Cwith the exception of
the vegetation estimates) upon measurements of standing crop and not
seasonal productivity. In addition, only the major biotic old-field
components are considered. A comprehensive view of DDT compartment-
a liza tio n ideally would be based upon a combination of community
productivity measurements and residue analyses which v/ould complement the measured gain and loss of community biomass and energy. Since the
present study was not designed to conform with these prerequisites, the
DDT compartmentaIization estimates presented here represent the minimal quantities of DDT translocated from the detritus to each biotic component.
The estimates are summarized in Table 43.
The most striking feature conveyed by these estimates is the small quantity of DDT translocated to the biota (56.41 g) relative to the
in itia l quantity applied (3005.57 g). Even if the estimate were expanded to 100 g in a rather liberal attempt to account for the DDT compartmentalized in all of the biota (excluding the microbiota and mesobiota of the soil and detritus) during the growing season, the DDT
in the b io tic component would represent only 3% of the DDT initially applied. Apparently, the bulk of the Insecticide was retained in the detritus, although the quantity of DDT actually compartmentalized in the 178
Table 43. Estimates of DDT compartmenta11zation in the major components of the o ld -fie ld ecosystem.
Initial DDT input i nto o ld -fie ld ecosystem 3005.57 g DDT loss in run-off to pond 1403 /ig DDT loss to atmosphere Unknown DDT in herbaceous (aerial portion! vegetation 53.57 g DDT in major invertebrate species Me 1anop1 us 704 jug Hadrobunus 6,751 Nernob i us 29,903 Gryllus 32.433 Paraj u1 us 979.025 Deroceras 1,778,555
Total DDT in major invertebrate species 2.83 g
DDT in small mammal populations Microtus 181 jjg Sorex 244 Blarina 11,713
Total DDT in small mammal populations 0.01 g
Potential loss of DDT from system through predation on small mammal species Microtus 61 ;jg Sorex 49 Blarina 2365
Total potential DDT loss to predation 0.002 g
DDT compartmentalized in biota during growing season 56.41 g 179
detritus was not measured in th is study. An unknown quantity of DDT
was probably lost from the detritus to the atmosphere through vaporiza
tion; some of the insecticide may also have been compartmentalized in
the soil through percolation from the detritus. Information on the
actual quantities of DDT in the detritus and soil as well as information
on DDT accumulation by soil microarthropods is expected to be made
available through the companion study conducted by Dr. D. L. Dindal of the State University College of Forestry, Syracuse, New York.
The detritus-inhabiting omnivorous invertebrate species are apparently
responsible for translocating a major segment of the insecticide away
from the detritus reservior to higher trophic levels. Although the compartmentaIization data are heavily weighted in favor of the omnivorous species (all but Melanoplus are omnivorous detritus feeders), comparatively little DDT is believed to have been compartmentalized among the invertebrates inhabiting the herb stratum. Low residue levels were detected in Me IanopI us (X = 0.13 ppm) and an extremely low residue level was detected during one collection in Philaneus spurmarius (0.003 ppm).
Furthermore, DDT was not detected among the herb stratum orb weaving spiders (Argiope trifa s c ia ta , A_. aurant i a, and Araneus t r i fo I i um) thus
indicating the low DDT levels contained in their herb stratum inhabiting prey.. . 180
Transfer of DDT to Avian Predators
An estimate was made of the DDT which potentially could have been transferred from the major species of o ld -fie ld small mammals to the native species of avian predators. The daily energy requirements of the kestrel and the screech owl (Plus asio) were those given by
Gatehouse and Markham Cl970). The kestrel (X weight = 104.68 g) required a minimum of 16.25 kcaI per 24-hr period whereas the screech owl (X weight
= 151.41 g) required 19.91 kcal per 24-hr period. Benedict and Fox (1927) gave the minimal daily energy requirement for the greot-horned owl
(Bubo v? rginianus; X weight = 1450 g) as 108 kcal. The metabolic rate- body weight equation given by lasiewski and Dawson (1967) was used in estimating the 24-hr energy requirements of the red-shouIdered hawk
(Buteo lineatus) and the red-tailed hawk (Buteo jamaicensis)because no published information is available. The body weight data u tiliz e d in the equation were those given by Craighead and Craighead (1956). The red shouldered hawk (X weight = 625 g) required 55.8 kcal and the red-tailed hawk (.X weight = I 126 g) required 85.3 kcal. Unfortunately, the energy requirements for all five species, whether measured or estimated, represent the requirements of resting birds {standard, or fasting, metabolic rates). Mo published active metabolic data are available for the raptor species considered here or for raptors in general. Obviously, the energy requirements and the levels of DDT consumed would be higher in active individuals.
In calculating the energy potentially available to an avian predator per unit of prey, the nondigostible portion of the prey carcass 181
(that portion of the carcass normally regurgitated as a pellet by predatory birds) was firs t determined. This information was based upon the tissue weight and the mean body weight data previously presented for
Mi crotus (Table 20) j BI ar i na (.Table 13), and SoreX (Table 17). The skeleton and the fur were categorized as nondigestible; the remaining so ft tissue was considered as an energy source. In the determination of tho tissue weight data for each prey species, the skin and fur were considered as a unit. Since the skin is digestible and the fur is not, the weight of the nondigestible fur was separated from the weight of the skin through the assumption that the fur represented one-fourth of the combined weight. The weights of the digestible and nondigestible portions of the carcasses of the three small mammal species are given in Table 44.
Table 44. Weight of the nondIgestible and the digestible portions of the carcasses of small mammal prey species.
Speci es Mean Body Weight of the Weight of the We i ght Nondigestible Portion Digestible Portion of Carcass of Carcass (grams) (grams) (grams)
Meadow Vole 32.90 8. 1 1 24.79
Short-tailed Shrew 15.90 3.84 12.06
Masked Shrew 3.34 0.80 2.54
The caloric content of the meadow vole carcass was based upon the caloric determinations made by Gol ley (.1960) for Microtus pennsy I van i cus and by Gorecki (1965) for M_. arva I i s . The tissues of Nh. pennsy I van i cus yielded 4650 cal/g dry weight or 1370 cal/g live weight based upon a 71$
loss of weight due to water loss during sample preparation. However,
Golley made no mention of.the season during which the voles used in the caloric determinations were taken, an important factor since caloric content is subject to seasonal variation. The caloric determinations made by Gorecki were based, however, upon summer-collected animals.
Summer caloric data is believed to be important in the present attempt to relate energy flow to DDT transfer based upon summer-collected residue data. The tissues of M. arvaIis produced 5116 cal/g dry weight and 1586 calories per gram live weight. Water loss during sample preparation was 69 % of the live weight. Therefore, a caloric value of 1478 cal/g live weight (mean value based on the combined data by Golley and Gorecki) will be used in the present calculations of meadow vole energy yield . This value represents a compromise between the species s im ila rity possessed by Golley's data and the seasonal s im ila rity possessed by Gorecki's data. The energy available to a raptor feeding on meadow voles having a mean body weight of 32.90 g and containing 24.79 g of digestible tissue would be 36.64 kcal.
The caloric content of the short-tailed shrew and the masked shrew carcasses was based upon the caloric determinations performed during th is study on the skeletal muscle of summer-captured short- ta ile d shrews. On a dry weight basis this tissue yielded 5197 cal/g.
The tissue contained 1476 cal/g on a live weight basis when adjusted for a 71.6$ weight loss during sample preparation. The live weight caloric value obtained for the muscle tissue of the short-tailed shrew is sim ilar to those values presented by Myrcha (1969) for summer- 183
collected Sorex araneus and S_. mi nutus (1454 and 1527 cal/g respectively).
Therefore, a short-tailed shrew- having a mean body weight 15.90 g and containing 12.16 g of digestible tissue would yield 17.95 Kcal. A masked shrew having a mean weight of 3.34 g and containing 2.54 g of digestible tissue v/ould yield 3.75 kcal.
To estimate the DDT consumed by each raptor species, the minimal number of prey animals consumed per 24-hr period or weekly was computed by dividing the caloric content of the digestible portion of the prey carcass into the minimal energy requirement for that period.
The quantity of DDT consumed by each raptor on diets of each prey species was computed by m ultiplying the number of each prey species consumed by the seasonal mean total body residue level for that species.
The resulting data are summarized in Table 45.
Although not considered in the present calculations, the energy and insecticide levels ingested by avian predators by way of the stomach contents of the prey species could be a source of error in estimating calo ric and insecticide intake. Since the small prey animals are ingested whole by raptors, the partially digested stomach contents would also be available along with the prey carcass for assim ilation by the raptor. Whereas the stomach contents of the herbivorous voles most likely do not contain significant quantities of insecticide and assimilable energy, the stomach contents of the shrews could transfer sizable quantities of both energy and insecticide containing material.
Buckner (.1964) found that the stomachs of the masked and short-tailed shrews feeding primarily on larch sawfly larvae contained an average of 0.13 and 1.21 kcal, respectively. However, both the energy and Table 45. DDT transfer from old-field small mammals to avian predators feeding on separate diets of each prey species.
Raptor Species
Kestre1 Screech Red-Shou1dered Red-Tai led Great-Horned Owl Hawk Hawk' Owl
Raptor Weight (grams) 104.68 151.41 625 1 126 1450
24-Hour Energy Requ i rement (kcal/25hr) 16.25 19.92 55.8 85.3 108.0
Weekly Energy Requ i rement ( kca1/week) 113.75 139.44 390.6 597.1 756.0
Number Prey Consumed per Week Microtus 3.1 3.8 10.6 16.3 20.6 . B!art na 6.3 7.8 21 .6 33.2 42.1 Sorex 3.0 3.7 104.1 159.2 201 .8 ppm DDT Consumed per Week on Separate Prey Diets3 Mi crotus 0.31 0.38 ! .06 1.63 2.06 B1 ari na 46.49 57.56 159.41 245.02 310.70 Sorex 3.24 4.00 112.43 171.94 217.94 Table 45. (Continued).
Raptor Species
Kestre1 Screech Red-Shou1dered Red-Tailed Great-Horned Owl Hawk Hawk Owl ppm DDT Consumed per Day on Separate Prey Diets Microtus 0.04 0.05 0.15 0.23 0.29 B!ari na 6.64 8.22 22.77 35.00 44.39 Sorex 0.46 0.57 16.06 24.56 31.13
a Seasonal mean total body DDT residue levels used in calculations: Mi crotus, X = 0.10 ppm; Blari na, X = 7.38 ppm; Sorex, X = 1.08 ppm. 186
insecticide content of the stomach contents would be subject to considerable variation depending upon the prey composition of the diet.
Although any of the five raptor species might conceivably feed solely on a diet of Mi crotus or Blarina for an extended period, a multiple species diet weighted to favor the more abundant or vulnerable prey species seems more probable. A diet consisting solely of Sorex might occur in the case of the smaller raptors; however, such a diet would be less lik e ly for the larger raptor species due to th e ir higher energy requirements and the relatively low energy content of the prey. To simulate the levels of DDT consumed by these raptors while on a mu I tiple- species d ie t, the spring-summer raptor food habits data given by Craig head and Craighead (1956) were used in setting the per cent composition of each of the three small prey species in the diet. All figures used in expressing per cent composition of the diet represent means for 2 years of data presented by these investigators. The estimates of DDT consumed on th is d ie t must be considered minimal since only three prey species are considered. The data relating to DDT consumpt’on by raptors on a multiple-species diet are given in Table 46.
From the foregoing discussion of energy utilization and DDT transfer, a clearer picture can be obtained of the dietary, or environmental, levels consumed by old-field feeding raptor species. For a given species of raptor feeding on the three species of small mammals ju s t considered, the key factor determining the level of DDT ingested is the diet composition. An a I I-Microtus d i et for any of the five raptor species would result in relatively low levels of DDT ingestion. However, a diet consisting entirely of Blarina could result in a 150-fold increase Table 46. DDT transfer from o ld -fie ld small mammals to avian predators based on the spring-summer food habits data by Craighead and Craighead (.1956).
Raptor Species
Kestre1 Screech Red-Shouldered Red-Tailed Great-Horned Owl Hawk Hawk Owl
Raptor Weight (grams) 104.68 151.41 625 1 126 1450
Energy Requirements for One Week Period (kcal/week) 113.75 139.44 390.6 597.1 756
Per Cent Composition of Summer Diet Mi crotus 76.0 29.8 30.0 51.3 30. 1 B1ari naa NRb NR ‘ 3.8 NR NR So rex NR NR 3.8 NR NR
Animals Consumed per Week Mi crotus 2.4 1 .6 3.2 8.3 6.2 B1 ari na - - 0.8 -- Sorex - - 0.8 -—
ppm DDT Consumed per Weekc Microtus 0.24 0. 16 0.32 0.83 0.62 Blari na -- 5.90 - - Sorex - - 0.86 -- Table 46. (Continued).
Raptor Species
Kestre! Screech Red-Shou1dered Red-Tailed Great-Horned Owl Hawk Hawk Owl
Total ppm DDT Consumed per Week 0.24 0.16 7.08 0.83 0.62 ppm DDT Consumed per Day 0.03 0.02 1 .01 0.12 0.09
a Due.to the absence of information concerning the species of shrew occurring in the diet, the per cent of the diet attributed to shrews by Craighead and Craighead CI956) was equally divided between Blari na and Sorex.
b NR Not represented in spring-summer diet.
c Seasonal mean total body_DDT residue levels used in calculations: Microtus, X = 0.10 ppm; Blari na, X = 7.38 ppm; Sorex, X = 1.08 ppm in the intake of DDT compared to an a I I-Microtus diet. A die t composed
solely of Sorex as opposed to a Mi crotus d iet would result' in a 10-fold
increase in DDT intake among the smaller raptor species, the kestrel and the screech owl. Normally, however, shrews compose only a small part of the to ta l raptor diet, being represented by a low percentage in the fa ll and winter diet and being a ll but absent in the spring and summer diet
(Craighead and Craighead, 1956).
The above dietary relationship between prey and raptor is valid only fo r o ld -fie ld areas which have not been sprayed with DDT during a current growing season. The manner of insecticide application used in the present study simulated a spray-treated area I year after an initial
DDT application. During a spray application, a large portion of the DDT would become entrapped on the cuticular surfaces of the herbaceous vegetation. This DDT would be readily available to feeding herbivores.
If the application rate were identical to that used in the present study, the herbivore tissue residue levels would considerably higher than those detected in animals from the Urbana site due to the increased herbivore accessibility to the insecticide. Therefore, raptors feeding on Microtus from an area sprayed during a current growing season would receive higher dietary levels of DDT. in the present study, even though DDT was detected in the vegetation, the bulk of the insecticide was compart mentalized in the detritus where it was relatively inaccessible to herbivores. On a spray treated area, the aerial portion of the vegetation would die and return the DDT to the detritus by the beginning of the second growing season. This latter condition was simulated on the
Urbana s ite . 190
Hickey and Anderson I9G8 found no correlation between eggshell thickness among stationary populations of red-tailed hawks and great horned owls and the advent of the use of DDT. In lig h t of the work performed by Heath et a l. (.1969) and the probable environmental dietary
levels of DDT presented here, resident raptor populations feeding pri marily on herbivores in an area where DDT had not been applied during a current growing season probably would not consume sufficient quantities of DDT to induce eggshell thinning. Heath et al. (1969) found that the
DDT metabolite DDE at dietary levels of approximately 3.3 ppm (wet weight; 10 ppm dry weight) induced reproductive impairment in mallards through shelI'thinning and increased embryo mortality. DDT induced shell thinning and reduced duckling survival were caused only by levels above
8.3 ppm DDT Cwet weight). DDT fed at wet weight concentrations of 0.8 ppm and 3,3 ppm (2.5 ppm and 10 ppm dry weight) did not produce measureable impairment of reproductive success. The authors indicate that DDE metabolized from DDT may have been responsible for the effects observed in ducks fed diets containing 8.3 ppm DDT. Apparently, diets containing 0.8 ppm and 3.3 ppm DDT do not result in DDE production at sufficient levels to induce reproductive abnormalities.
If the data provided by these investigator fo r mallards are applicable to predatory birds, no reproductive impairment should be detected among old-field feeding raptors feeding on herbivores under the conditions outlined above. However, should the number of shrews
in the diet increase due to a change in the availability and vulner ability of that prey species relative to Microtus, the 8.3 ppm threshold could definitely be reached in the daily diets of the red-shouIdered and red-tailed hawks and the great-horned owl (.Table 45). Since DDE is known to be the metabolite chiefly responsible for reproductive failures the threshold might be lowered if DDE were present in high enough levels
In the present study the analytical method did not distinguish between
DDT and its metabolites. No metabolite determinations were made by other methods following the application of the labeled insecticide.
However, Dimond and Sherburne (1969) found that DDE composed 57$ of the total residues in shrews collected in the DDT treated forests of northern Maine. If th is percentage were applied to the mear to ta l body residue level for the Urbana BIarina (7.38 ppm), 4.21 ppm of DDE would be present. One BIarjna in the daily diet of a raptor would provide sufficient DDE to exceed the 3.3 ppm threshold value. SUMMARY
DDT labeled in the ring position with the radioisotope chlorine-36
was used to measure the rates of bioaccumulation and translocation of
the insecticide in an intact old-field ecosystem. Ninety-four grams of
labeled DDT having an a c tiv ity level of 10.2 me and 4.54 kg of nonlabeled
technical grade DDT wore formulated and applied to a 4.05-ha old-field
study plot located in Salem Township, Champaign County, Ohio, on June
10, 1969. The insecticide was applied in the form of an impregnated
attapulgite clay granule using a helicopter and a rotary type applicator.
The efficiency of the insecticide formulation and application was
66.18?; the rates of application of the nonlabeled and labeled DDT were
0.74 kg/ha (0.66 lb/acre) and 1.67 mc/ha (0.68 mc/acre), respectively.
The low efficiency is attributed to the loss of the insecticide during
the formulation rather than during the time of application. Based upon
the known proportions of labeled and non labeled DDT used in the
formulation and the formulation and application efficiency, I p g of
nonlabeled DDT was equivalent to 7.56 dpm originating from the chlorine-
36 labeled DDT.
Liquid scintillation counting was the method used to measure the
levels of labeled DDT contained in the old-field biota.
Sampling of the o ld -fie ld biota was in itia te d on June 16, 1969;
samples were collected at weekly intervals during the firs t month and
thereafter at monthly intervals u n til the end of the growing season in mid-October. A sample consisting of four subsamples of each organism or tissue was collected from the treated area and from the control
192 193
area during each collection period. An individual subsample from the
treated area was considered to contain DDT (.both chlorine-36 DDT and
non labeled DDT) when the number of dpm for that subsampIe exceeded the
level of background radiation represented by the control mean dpm plus
a 99$ confidence interval.
During 1969, the leaves of 10 plant species displayed radiation
levels in excess of the control, or background, radiation levels.
Although some variation in pre-appIication radiation levels was observed between the control and the study area vegetation samples
during 1968, the higher radiation levels detected in the study area
vegetation during 1969 is attributed to the chlorine-36 DDT. Since the
DDT translocation from the soil via the roots and vascular tissue is an •
unlikely route of plant contamination, DDT vaporization from -the soil
followed by condensation on the plant surfaces is thought to be the mechanism of contamination prevailing on the old-field study site.
A series of six, 24-hr air samples was collected on the study
area between August II and August 27, 1969, to determine the possible
loss of DDT to the atmosphere by vaporization or codistillation. No
DDT was detected.
The highest levels of DDT detected among the invertebrate species were found in the slug Oeroceras sp. (seasonal X = 18.99 ppm). DDT was also detected in the miUtped Parajulus sp. (seasonal X = 3.96 ppm), the phalangid Hadrobunus sp. (.seasonal X = 1.06 ppm), the red-legged grasshopper (seasonal X = 0.14 ppml, the lesser field cricket (seasonal
X = 1.66 ppm), the greater fie ld cricket (seasonal X = 0.74 ppm) and the camel cricket (collection X = 0.31 pprn). 194
Among the vertebrate species, the highest DDT residue levels were detected in Blarina brevicauda. Maximum residue levels'were detected
in the skeletal muscle C31.12'ppm), live r (64.95 ppm), and lung (12.43
ppm) at 60 days post-application. Maximum residue levels in the
kidneys (22.20 ppm), brain (10.05 ppm), heart (21.49 ppm) and skin and
fur (29.53 ppm) occurred at 126 days. The mean total body residue
level for Blarina was 7.38 ppm (range: 2.20 ppm - 13.70 ppm).
The mean total body residue levels of DDT detected in Sorex ci riereus and in Mi crotus ponnsy Ivanicus were 1.08 ppm and 0.10 ppm,
respectively. DDT was also detected in the tissues of Mustela vison,
SyIv i Iagus flo r i danus, Peromyscus leucopus, Age I a i us phoen i ceus,
Phas i anus coIch i cus, and Thamnoph j s s i rta Ii s .
The patterns of DDT storage in Sorex and Microtus were character
ized by rapid DDT accumulation during the firs t month post-application
followed by decreasing and stationary levels of storage during the
la tte r half of the growing season. The pattern of storage in BIari na was characterized by a steady increase in DDT storage throughout the summer and early f a ll.
Although Sorex has a higher metabolic rate and consumes more
food and th eo retically more DDT per gram of body weight compared with
BIari na, Blari na accumulated higher levels of DDT per gram of body weight than did Sorex. The difference in DDT accumulation observed between the two species of shrews may re fle c t either I) a mechanism of niche segregation involving a difference in the size prey taken by each species and a resulting difference in the levels of DDT ingested or 2) physiological differences. I 95
During the firs t 3 weeks post-application, DDT associated with
particulate matter was transported by run-off to a smaI I pond located ju s t beyond the northwestern study area boundary. After th is in itia l
period, DDT was not detected in the particulate samples. The presence of DDT in these samples during the firs t 3 weeks indicated that the
insecticide was s till partially associated with the clay granule
c a rrie r. The absence of the DDT from the samples taken a fte r the f i r s t month marked the complete leaching of the insecticide from the granule and the incorporation of the compound into the old-field detritus.
Chara, Myriophy I I urn, adult bullfrogs and bullfrog tadpoles taken from the contaminated pond contained DDT residues at some point during the summer. No residues were detected in a filamentous alga (Chlorophyceae), dragonfly nymphs, backswimmers, flathead minnows and cricket frogs.
The net primary production of the old-field community was estimated by the short-term harvest method to be 447.1 g dry weight/m^.
Grasses and sedges accounted fo r 60.4# or 305.7 g dry weight/m^ of the to ta l production; forbs accounted for 31.6# or 141.5 g dry weight/m^ of the total production.
An estimate of the DDT compartmentalized in the old-field ecosystem indicates that 3# or less of the DDT initially applied to the old-field was compartmentalized in the biota (excluding the microbiota and mesobiota of the soil and detritus) during the growing season. The bulk of the insecticide, apparently, was retained in the detritus, although the quantity of DDT actually compartmentalized in the detritus was not measured. An unknown quantity of DDT was probably lost from the detritus to the atmosphere through vaporization and to the soil 196
through percolation.
Based upon estimates of raptor energy requirements, the
digestible energy content of small mammal prey species, and the residue
levels in small mammal prey species, native o ld -fie ld feeding raptors
could acquire DDT and DDE at levels which are known to produce
reproductive failure in avian species under experimental conditions.
However, the level of DDT and DDE intake is dependent upon the species
composition of the raptor diet. Under the conditions prevailing in
this study, a diet consisting of the herbivore Microtus would most
likely not subject the raptor to hazardous levels of the insecticide.
In contrast, a diet consisting of shrews, especially BIari na, could
increase DDT and DDE intake to hazardous proportions. The availability
and vulnerability of each prey species population relative to other
prey species populations would determine the environmental levels of
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Table 47. List of vegetation occurring on study area, Urbana Wildlife Area, Champaign County, Ohio, 1963 and I969a .
Grami neae Agropyron repens (L.) Beauv. DactyIi s glomerata L. Phleum pratense L. Poa spp. Pan i cum sp. Setaria glauca CL.) Boavu. HIerochIoe odorata CL.) Beauv. Xea mays L.
Cyperaceae Carex spp.
Araceae Arisaema dracontium CL.) Schott.
Iridaceae S i syr i nch i urn sp .
Li I iaceae Allium vi neale L. Smi lax "ipT
Juglandaceae Carya ovata (Mill.) K. Koch
Fagaceae Quercus b icol or W iI Id.
UImaceae UImus amoricana L.
Moraceae Morus rubra L.
U rti caceae Urtica dioci a L.
Rosaceae Crataegus sp. Potent i I fa recta L. Potent i I I a s imr> lex Michx. Prunus serotina Ehrh.
206 207
Table 47, (Continued.)
Rubus a 11eqhon i ens i s P ort. Rubus occi dentaIi s L. Rosa pa Iustr i s Marsh.
Legumi nosae Tri fo li um pretense L. Trj fol j urn repens L. Trl f o I i urn agrariurn L. Lespedeza sp. Med j cago sativa L.
OxaIi daceae OxaIi s s tric ta L. (Ch europaea Jord.)
Anacard i accae Rhus rad i cans L.
V i taceae V i t i s vuIp i na L. Parthenocissus quinquefolia (L.) Planch.
MaIvaceae AbutiIon theophrasti Modic
Hypericaceae Hypericum perforatum L.
Onagraceae Oenthera biennis L.
Cornaceae Cornus sp.
UmbeI Ii ferae Pasti naca sativa L. Daucus caroTa L.
Polygonaceae Rumex crispus L. poIygonum convoIvuI us L.
Chenopod i aceae Chenopodium a I bum L.
Amaranthaceae Amaranthus sp. 208
Table 47. O'Conti nued.)
Phy+olaccacaae Phytolacca americana L.
PortuIacaceae Clayton i a vi rgi n i ca L.
Cruel ferae Brassica rapa L. Pentari a heterophyI I a Nutt. ThIapsi arvonse L. Lepjgjurn campostre ( I.) R. Br. Cardamine bu I bosa (Schreb.) BSP.
AscIep i adaceae AscIspias syriaca L. Asclep i as tuberosa L.
Apocynaceae Apocynum cannabi nurn L.
Borag i naceae Cynoe I os sum off ici na le L.
Verbenaceae Verbena u rtic i fo lia L.
Lab i atae Mentha pipe rita L. Leonuru "ca'rdioca L. Ga I eo'ps ] 5 tetrah i t L. Prune I I a vuI gar i s L. Lycopus sp. Nepeta cataria L.
Solanaceae Solanum nigrum L. Solarium caroI I nense L. Physai is IongifoIia Nutt.
Scrophulari aceae L i narj a vuI gar i s H ill Verbascurn thapsus L. Verbascum bI atta ria L. Veron.'icastrum virginicum CL.) Farw. Scrophu I ar i a lanceolata Pursh. 209
Table 47. (Continued).
PIantag i naceae PI antaqo lanceolata L. PIantago major L.
Capri foliaceae Sambucus canadensIs L.
Rub i aceae GaIj um sp.
CampanuIaceae SpecuIaria perfoi iata CL.) A.DC. Lobe Ii a i nfIata L. Lobe Ii a s i ph i i i t i ca L.
Composi tae /' Ach i I lea mi I I i fol iurn L. Arctiurn sp. / C i rs i urn arvcnse (L.) Scop. Cirsiurn discolor (Muhl.) Spreng. C i rs i um vulqarc (Savj) Tenore Taraxacum o f f i c i naIe Weber Soli dago juncea A it. Ambrosia artoini si I fol ia L, Arnbros i a t r i f i da L. Tragopogon pratensi s L. Vernon i a novesboraconsi s (L.) Mi chx. C i chorium i ntybus L. Lactuca scar ioI a L. Erigeron'canadonsi s L. Erigeron ph i IadeIphicus He Ii anthus sp. Aster ericoides L. Aster sp.
PrimiJ Iaceae Lys imach ia sp.
a Nomenclature according to Weishaupt (.1968) 210
Table 48. L ist of insects occurring on study area, Urbana W ild life Area, Champaign County, Ohio, 1968 and 1969.
Orthoptera
Acrididae Me lanop I us f emur-rubrurn femur-rubrum (DeGeer) Encopto I ophus sord i dus sord i dus lJurm. Cliorthippus curti nerin is curtipcr.ni s Harris Dichromorpha v irid is (Scudder)
Tett i gon i i dae Conocephalus nemdralis (Scudder) ConocephaI us brev i penn i s (5cudder) Conocepiia I us strictus (Scudder) Qrchelimum vulgare Harris NeoconocephaI us ensiqer (Harris) Scuddera t oxensis Saussure and Picket Ceuthoph iI us d i vergens (Scudder)
GryI Ii dao Qecanthus quadripunctatus Beutenmuiiler Nemobjus allard i A I ox. and Thomas GryI I us pennsyI van icus Burm.
Mantidae Tenodera arid i fo Ii a si nens i s Saussuro
Co Ieoptera
ChrysomeIi dae Diabrotica longicornis barberi S. and L. Piabrotica undecimpuncfatus howardi Barber Chrysochus auratus (Fab.) Lepti notarsa juncta (Germax) Trirrhabda vigata Lee. Zygogramma suturaIis (Fab.) Lab i domera cIi v i coI Ii 5 Ki rby
Cocc i ne1 Ii dae H i ppodami a parenthesi s (Say) Hippodamia tredecimaunctata (L.) Hippodamia convergens Guerin Meg ilia macuIata Mu I sant Table 43. (Continued.)
Coleoptera
Cocci ne! 11dae Hyperaspis unduIata (Say) CycIoneda munda (Say) Ada Ij a b i punctata L. Pr.y I loborn 20-macu I ata (Say) Hrachycantha ursi na (P.)
E I a to ri dae Melanotus sp. Hcmi crop i d j us me IanophthaImus (Me I sh.) Komi crop i d i us' sp. AeoI us sp. Canthar i s b ill neatus Say
Me I as i dae Dejtometopus amoenicornis (Say)
Cleridae EnocIerus rosmarus (Say)
CurcuIi on i dae Lixus concavus Say Hyp era' post'ica' (Gy I I .) Sit'ona- hispidula (Fab.)
MorcJe I I i dao NibrdeI I istena sp.
Larnpyridae Photi nus pyraIi s L.
Me 1oi dae Meloe sp.
Hydrophy i t dae Tropisternus IateraIi s F.
Geotrupidae G-aotrupes splendidus (Fab .)
Carab i dae Scarites substriatus Ha Id. 212
Table 40, (Continued.)
Coleoptera
Carab i dae Harpa1 us caIi n i nosus (F.) Harpa I us pennsy I van i cus DeGeer HarpaI us b i coI or Fab. HarpaI us fa I lax LeContc Pterost i chus styg i cue bay Ptoroat i chus I ucub I andus Say Abac idus permundus Say Ca I athns nroqar i us Say Amara rubrica Ha I deman An i sol arsus terrni natus Say CaI lei da decora Fab,
Scarabaei dae Onthophagus hecale (Panzer) Cop i s rni nutus (Drury) Aphod i us sp. Dichelonyx sp. Aphonus sp.
Si Iphidae Nicrophorus fomentosus Web.
Tenebrion i dae Mcracantha contracta Bcauv.
Cerambycidao Tetraopes tetraophthaIrnus (Foster?
N i t i duIi dae Gli schroch iI us fasciatus (01i v.) Gl i schroch i I us quadr i s i gnatus (Say)
Canthar!dae Chau] ioqnathus marginatus (Fab.)
PhaIacri dae (unidentified family representative) 213
Table 48 (Continued).
Lepi dop+era
Satyri dae Cercyonis pegala (Fab.)
Pap iIio n i dae Papi 1io poIyxenes StolI
P ieri dao Coli as ph i 1od i ce La+rielle P ieri s rapao (L.)
Nyrnpha I i dac NymphaI ?s mi Ibertj Latrei ! le Polyqon i a i nterroqati on i s Fab. Phyc i odes I’liar os Drury Speyeri a cyboIe (Fab.)
Hi ptera
Sciomyz i dae Sepodon fuse j penn i s Lw. Sopcdon armi pes Loew
Ti pu t i dae Ti puI a sp.
Stratiomyidae S trat i omys sp.
Bomby1i i dae BombyIius sp.
Musci dae (unidentified family representatives)
Tachi nidae (unidentified family representatives)
T rupanei dae Euaresta be II a (Loew)
Neuroptera
Chrysop i dae Chrysopa plorabunda F i tch 214
Table 48. (.Continued).
Hymenoptera
Ap i dae Bombus americanorum Fab. Bombus impati ens Cress Ap i 5 me I Iife r a L.
Tenthred i n i dae Do I crus unicoI or (Beau.) Dolerus sp.
Andren i dae (unidentified family representatives)
H alictidae (unidentified family representatives)
Fonnicidae (unidentified family representatives)
I chneurnon i dae Me I an i chneumon brevi ci ncfor (Say) Ceratogastra ornata (Say)
Hemi ptera
Lygaei dae Oncopeltus fasciatus (Dallas)
Cori 7. i dae Cori zus sp.
Nab i dae Nab is subcoIeoptratus (Kirby)
Corime I aeni dae AIlocari s pu i Ii caria (Germar)
Mi ridae Lygus pratgns i s L, M i r i s do Iabratus L. Stenotus b inotatus F. PIagiognathus poIitus Uhler
Pentatomidae Coenus deIius (Say) Eusch i stus variola ri us Pa t isot-Beauvois Acrosternum hi iaris Say 215
Table 48. (Continued).
Hemi p+era
Trichopoola atricornis Stal Per i baIus Ii mhoI a r i us StaI Cosmopep I a b irnacu I ata Thomas
Homoptera
Cercop i dae Philaenus spufnarjus (L.)
Cicada I Ii dao Dorotura sty Iata (Boh.) Gyponana sp. DraecuIacophaI a sp. ChIorotot M_x un i coI or (Fitch) Athysanc I l_a acuti cauda Baker Come I I us coIon Osborn and Ba I I Parabolocratus viridis (Uhler)
FuIgori dae Scolops sulei pes Say
Meinbrac i dae Ceresa bubalus F. 216
Table 49.. Partial list of invertebrate species (excluding insects) occurring on study area, Urbana W ildlife Area, Champaign County, Ohio, 1968 and 1969.
Mollusca
Gastropoda Stylommatophora Zon i toi dcs orboreus Deroceras sp.
Arthropoda
Arachn i da PhaIang i da Hadrobunns sp. QdioI jus pi eta
Araneae Araneus t r i fo I i urn Argiope aurantia Argi ope trifa s c ia ta Neuscona sp. T i be I I us obIongus Mi sumenops sp.
Diplopoda JuIi formia ParajuI us sp.
Ch iIopoda Li thob iomorph i a Lithobius sp.
Crustacea Isopoda CyIisticus sp. 217
Table 50. L ist of vertebrate species occurring on the study area, Urbana W ild life Area, Champaign County, Ohio, 1968 and 1969.
R eptiIi a
Colubridae Thamnoph i s s i rta Ii s
Aves
Icteri dae Polichonyx oryzivorus Sturne I I a magi!a Ago I a i us phoen i ceus
FringiI Iidae Spi nus t r is l i s Mo I os pi 7. a mo lod i a
Phas iani dae Phasianus colchicus Co Ij nus v i rg i n i anus
Mamma Ii a
Sori c i dae BIari na brovicauda Sorex ci rioreus
TaIpi dae Sealopus aquati cus
Cricet i dae Pcroinyscus I eucopus Mi crotus ponnsy1 van j cus
Zapod i dae Zapus hudson i us
Muridae Mus muscuI us
Sc i uri dae Marmota monax 218
Table 50. (Continued).
Mamma Ii a
Lepor i doe Sylvilaqus floridanus
Musts Ii dae MusteI a vi son Mus'to I a n i va I is MusteI a frenata Meph jt i s memph i t i s
Procyon i dae Procyon lotor 219
Table 51. Chlorine-36 labeled DDT radioactivity levels occurring at petri dish sampler stations, Urbana Study Area, June IQ, 1969.
Grid dpm Grid dpm Grid dpm Number Number Number
1 132 39 370 77 2594 2 186 40 394 78 2428 3 91 41 776 79 1228 4 68 42 522 80 3199 5 45 43 1770 81 1941 6 24 44 3280 82 1965 7 51 45 4105 83 4228 8 294 46 3056 84 2891 9 135 47 521 85 5731 10 244 48 443 86 12623 I 1 141 49 2548 87 20339 12 162 50 7002 88 2514 13 268 51 4926 89 3823 14 154 52 7624 90 2790 15 90 53 6878 91 95 16 235 54 4644 92 6103 17 180 55 3909 93 1352 18 60 56 7186 94 1967 19 55 57 4129 95 1035 2 0 9 58 2366 96 1452 21 12 59 2400 97 1593 2 2 89 60 7529 98 4451 23 96 61 5197 99 1759 24 176 62 2995 100 1063 25 493 63 1839 101 4291 26 255 64 208 102 1720 27 180 65 1880 103 3612 28 437 66 I860 104 3644 29 363 67 1 105 1995 30 2 0 2 6 8 8867 106 478 31 238 69 5291 107 6240 32 281 70 7766 108 1798 33 502 71 8922 109 77 34 371 72 9183 1 10 175 35 344 73 7068 1 1 1 191 36 154 74 3577 1 12 3893 37 349 75 4291 1 13 201 1 38 124 76 1332 1 14 333 220
Tab le 51. (.Continued).
Grid dpm Grid dpm Gri d dpm Number Number Number
1 15 1546 156 7435 197 2208 1 16 3104 157 2912 198 500 117 2089 158 6938 199 1 146 118 290 159 2719 200 41 18 1 19 332 160 1654 201 1233 120 200 161 4749 202 1086 121 - 162 6431 203 237 122 3083 163 5870 204 487 123 1078 164 5030 205 2309 124 1 152 165 4616 206 1711 125 4258 166 3432 207 265 126 5033 167 5095 208 - 127 4703 168 4848 209 1652 128 - 169 2227 210 1296 129 1942 170 3112 21 1 2024 130 1564 171 1 155 212 1803 131 4121 172 2318 213 101 1 132 1048 173 1261 214 1071 133 631 174 1618 215 1 171 134 426 175 2578 216 3382 135 384 176 3005 217 2165 136 2271 177 3149 218 2378 137 6342 178 6512 219 2389 138 790 179 4974 220 4502 139 600 180 2719 221 5660 140 1257 181 1981 222 2723 141 3572 182 2893 223 1633 142 935 183 5966 224 2754 143 - 184 3881 255 8319 144 75 185 2737 226 3803 145 208 186 8130 227 3978 146 5519 187 14634 228 5023 147 181 1 188 3894 229 8329 148 1295 189 2087 230 3729 149 3184 190 1 180 231 1260 150 3716 191 2185 232 860 151 4694 192 4234 233 1868 152 2290 193 5162 234 1875 153 6363 194 1645 235 966 154 8638 195 1391 236 1449 155 8849 196 4323 237 2291 (Conti nued).
Gr dpm Grid dpm Grid Num Number Number
238 2013 280 134 322 239 2652 281 65 323 240 2106 282 24 324 241 2918 283 69 325 242 4494 284 640 326 243 4201 285 3(47 327 244 2232 286 3057 328 245 5550 287 1804 329 246 4589 288 2598 330 247 2404 289 — 331 248 2596 290 1 107 332 249 2450 291 825 333 250 3825 292 959 334 251 3163 293 2782 335 252 5550 294 5320 336 253 7451 295 6176 337 254 3203 296 0922 338 255 1280 297 7322 339 256 539 298 2524 340 257 569 299 2101 341 258 3314 300 8598 342 259 1608 301 321 1 343 260 763 302 2488 344 261 689 303 1094 345 262 2972 304 2991 346 263 2 0 1 2 305 361 347 264 157 306 1 174 348 265 694 307 74 349 266 423 308 186 350 267 1027 309 829 351 268 6566 310 6439 352 269 1291 31 1 658 353 270 631 312 308 354 271 1254 313 766 355 272 1098 314 2263 356 273 2738 315 1 180 357 274 1686 316 832 358 275 1419 317 2500 359 276 988 318 642 360 277 894 319 597 361 278 859 320 1201 362 279 6544 321 4504 363 222
Tab le 51. (Conti nued).
Grid dpm Grid dpm Number . Number
364 426 404 6867 365 748 405 9887 366 3909 406 7384 367 637 407 6708 368 793 408 4785 369 1720 409 3539 370 3981 410 5272 371 2674 41 i 7892 372 2213 412 1230 373 969 413 10583 374 228 414 14551 375 373 415 1456 376 231 416 3755 377 2251 417 3416 378 3605 418 3549 379 7862 419 6995 380 3040 420 9499 381 3264 421 4415 382 3179 422 2108 383 1461 423 440 384 3126 424 166 385 7724 425 196 386 4691 426 1503 387 4176 427 1 152 388 4426 428 2971 389 31 1 1 429 2258 390 1789 430 744 391 2234 431 1485 392 1439 432 857 393 2724 433 422 394 8310 434 277 395 4798 435 986 396 2586 436 1496 397 6367 437 2454 398 15145 438 5435 399 1425 439 3470 400 1303 440 2561 401 6634 441 6951 402 10354 403 8963 Table 52. Background radiation levels fo r study area and control area vegetation (leaves), Urbana W ild life Area, 1968. 5A = study area, CA = control area; ** sign ificant difference between control area and study area means (P 0.01).
Col lection Species and X dpm ± S.E. Coefficient X dpm + 99% Date Locat ion (Number Subsamples) of Variation Confidence Interval (one-ta i 1 t di stri bution)
Dacty I i s glomerata
6 / 1 /6 8 SA 154.34 + 4.13 (3) 4.63 CA 149.20 ± 3.80 (4) 5.09 166.45
7/5/68 SA 155.61 ± 6.83 (4) 8.78 CA 144.70 ± 2.13 (4) 2.94 154.37
8/7/68 SA 148.19 ± 4.66 (4) 6.30 CA 147.30 + 2.92 (4) 3.97 160.56
9/10/68 SA 177.56 ± 8.56 (4) 9.64 CA 165.44 + 9.54 (4) 1 1.53 208.75
10/13/68 SA 173.10 ± 1.9! (4) 2 .2 1 181.61 CA 176.03 ± 1.14 (4) 1.30
Agropyron repens
6 / 1 /6 8 SA 154.56 ± 4.79 (4) 6 . 2 0 173.91 CA 150.21 + 5.22 (4) 6.95
7/5/68 SA 147.31 ± 5.18 (4) ■ 7.03 162.80 CA 153.58 ± 2.03 (4) 2.64 Table 52. (Continued).
Collection Species and X dpm - S.E. Coefficient X dpm + 99% Date Location (Number Subsamples) of Variation Confidence Interval (one-taiI t distribution)
8/7/68 SA 161.08 + 2.52 (4) 3.13 CA 145.52 + 3. 10 (4) 4.26 159.59 **
9/10/68 SA 148.76 + 4.66 (4) 6.26 CA 145.44 - 1.78 (4) 2.45 153.52
Poa sp. + 6 / 1 /6 8 SA 149.33 8.84 (4) I ! .84 189.46 CA 149.67 + 5.56 (4) 7.42
7/5/68 SA 138.36 + 2.25 (4) 3.25 148.58 CA 143.88 + 2.34 (4) 3.25
8/7/68 SA 144.37 + 2 . 18 (4) 3.01 154.27 CA 145.15 1 4.04 (4) 5.56
9/10/68 SA 145.84 + 4.77 (4) 6.53 157.50 CA 146.55 + 2 . 2 0 (4) 3.00
10/13/68 SA 149.24 + 4.46 (4) 5.97 169.49 + CA 159.0! 8 .0 1 (4) 10.07 224 Table 52. (Continued).
Collection Species and X dpm ± S.E. Coef f i ci ent X dpm + 99% Date Location (Number Subsamples) of Variation Confidence Interval (one-taiI t d i s tri buti on)
AchiI lea mi Ilefo!iurn
6 / 1 /6 8 SA 137.58 ± 4.55 (4) 6.61 158.23 CA 139.82 + 2.63 (4) 3.75
7/5/68 SA 147.58 - f 1.64 C4) 4.25 161.84 CA 154.26 z 4.07 (4) 5.27
8/7/68 SA 148.39 J. 1.41 (4) I .89 4 _ CA 133.72 1 .33 (4) I .98 14- 4*99
9/10/68 SA 165.44 T 7.35 (4) 8.89 CA 148.49 - 3. 10 (4) 4.17 163.68 **
10/13/68 SA 164.00 4 * 3.40 (4) 4.15 CA 150.20 *r 2.97 (4) 3.95 163.70 **
Soli dago juncea
6 / 1 /6 8 SA 158.20 + 14.96 (4) 18.91 CA 157.69 + 4.76 (.4) 6.04 179.30
7/5/68 SA 160.94 + 2.25 (4) 3.62 225 CA 150.56 ± 2.35 (3) 3.73 165.27 Table 52. (Continued).
Collection Species and X dpm ± S.E. Coeff icient X dpm + 99£ Date Location (Number Subsamples) of Variation Confidence Interval (one-tai 1 t di stri bution)
Ach i 11ea mi 11e fo 1i urn
6 / 1 /6 8 SA 137.58 + 4.55 (4) 6.61 158.23 CA 139.82 j . 2.63 (4) 3.75
7/5/68 SA 147.58 1.64 (.4) 4.25 161.84 CA 154.26 + 4.07 (4) 5.27
8/7/68 SA 148.39 + 1.41 (4) I .89 CA 133.72 j . 1 .33 (4) t .98 144.99
9/10/63 3 A 163.44 - r 7.35 (4) 8.89 CA 148.49 - 3. 10 (4) 4. 17 163.68 **
10/13/68 SA 164.00 t 3.40 (4) 4.15 CA 150.20 + 2.97 (4) 3.95 163.7C **
Sol 1daao juncea
+ 6 / 1 /6 8 SA 158.20 14.96 (4) 18.91 CA 157.69 + 4.76 (.4) 6.04 179.30
7/5/68 SA 160.94 + 2.25 (4) 3.62 225 CA 150.56 ± 2.35 (3) 5.73 165.27 Table 52. (Continued).
Col lection Species and X dpm - S.E. Coeff icient X dpm + 99$ Date Location (Number Subsamples) of Variation Confidence Interval (one-taiI t di stri bution)
So 11 dago j uncea
8/7/68 SA 147.62 + 2.50 (4) 3.39 158.98 CA 150.!1 + 4.30 (4) 5.72
9/10/68 SA 164.33 + 3. 18 (4) 4.86 CA 145.43 + 3.87 (4) 5.32 163.03
10/13/68 SA 160.44 + 10.82 (4) 13.48 207.04 CA 168.12 5.84 (4) 7.04
C i rs i urn arvense + 6 / 1 /6 8 SA 148.28 3.46 (4) 4.67 163.99 CA 154.32 + 3.93 (4) 5.09
7/5/68 SA 145.67 + 2.26 (4) 3. 10 CA 144. 14 + 2.79 (4) 3.87 156.81
8/7/68 SA 144.23 j . 2.98 (4) 4. 13 CA 144.22 x 3.59 (4) 4.97 150.01
X 9/10/68 SA 156.05 5.68 (4) 7.28 226 CA 142.59 + 3.77 (4) 5.29 159.71 Table 52. (Continued).
Collection Species and X dpm - S.E. Coefficient X dpm + 99 % Date Location (Number Subsamples) of Variation Confidence Interval (one-taiI t distribution)
Daucus carota
7/5/68 SA 147.16 + 5.88 (4) 7.98 CA 142.49 + 2.79 (4) 3.91 155.16
8/7/68 SA 152.06 + 6.46 (4) 8.48 CA 141.64 + 1 .39 (4) I .96 147.95 **
10/31/68 SA 165.29 + 3.83 (4) 4.52 CA 155.42 + ! .90 (4) 2.^5 164.09 **
Pasti naca sat i va
6/1/69 SA 137.74 + 5.86 (4) 8.51 CA 135.84 X 2.30 (4) 3.38 148.28
7/5/68 SA 144.85 + 3.56 (4) 4,92 161.01 CA 148.96 + 1.59 (4) 2. 13
+ 8/7/69 SA 142.47 4.41 (4) 6 . 18 CA 141.59 T 2.15 (.4) 3.03 151.35
X 9/10/68 SA 169 . 11 9.99 (3) 7.96 CA 157. 1 1 + 4.08 (4) 2. 13 175.63 227 Table 52. (Continued).
Collection Species and X dpm 1 S.E. Coefficient X dpm + 99% Date Location (Number Subsamples) of Variation Confidence Interval (one-taiI t di stribution)
Pasti naca sativa
10/13/68 SA 166.80 + 4.06 (4) 4.52 197.01 CA 170.86 5.73 (4) 2.45
Carex spp.
+ 6 / 1 /6 8 SA 141.50 5.29 (4) 7.48 165.52 CA 145.20 + 3.56 (.4) 4.90
Aster eri coi des
8/7/68 SA 147.89 + 3.47 (4) 4.69 154.27 CA 147.85 + 3.62 (4) 4.89 + 10/13/68 SA 166.11 5.60 (4) 6.74 CA 164.17 + 6.40 (4) 7.80 193.23
Erigeron sp.
7/5/68 SA 149.34 + 2.23 (4) 2.98 CA • 144.49 + 3.53 (4) 4.89 160.52 228 8/7/68 SA 153.03 + 4.90 (4) 6.49 CA 144.20 + 0.65 (4) 0.90 147.15 Table 52. (Continued).
Col lection Species and X dpm t S.E. Coefficient X dpm + 99$ Date Location CNumber Subsamples) of Variation Confidence interval (one-taiI t distribution)
Vernonja noveboracensi s
6 / 1/68 SA 142.96 t 3.36 (4) 4.69 153.2! CA 152.21 i 5.18 (4) 6.89
7/5/68 SA 143.86 + 2.59 (4) 3.60 159.42 CA 149.79 ± 4.06 (4) 5.41
8/7/68 SA 156.54 + 9.52 (4) 1 2 . 16 CA 151.30 t 4.69 (4) 6.19 172.59
9/10/68 SA 188.13 ± 4.27 (4) 4.54 CA 152.06 ± 5.5! (4) 7.24 177.08
Phleum pratense
7/5/68 SA 141.73 ± 2.44 (4) 3.44 152.81 CA 143.89 + 4.62 (4) 6.41 230
Table 53. Background ra d ia tio n . levels for control vegetation Cleaves), Urbana Wildlife Area, 1969.
Species and Days X dpm ± S.E. C oefficient X dpm + 99$ Post-Application (Number Subsamples) of Variation Confidence Cone -ta iI t distribution)
Dactyl is alomerata
+ 6 156.00 2.87 (4) 3.68 169.03 16 153.00 + 4.35 (4) , 5.48 178.14 23 171.41 + 4.30 (4) r 5.01 190.93 29 154.98 •t* 5.83 (4) ■ 7.49 181.34 62 157.76 + 6.27 C4) 7.95 186.24 92 196.06 + 1 1 .8 6 C4J 12.15 248.87 122 163.77 + 4.13 (4) 5.03 182.49
Agropyron repens
+ 6 203.38 4.14 (4) 4.06 222.18 16 233.94 + 4.78 (4) 4.08 225.33 23 162.58 + 2.28 (4) 2.80 172.93 29 144.52 ± 2 . 0 2 (4) 2.79 153.69
Poa sp.
6 195.09 + 9.77 (4) 10.01 231.42 16 207.63 + 1 1.46 (4) 1 1.03 259.66 23 151.35 + 4.54 (4) 5.90 171.96 29 167.38 + 8.98 C 4) 10.73 208.16 62 170.95 + 7.29 C 4) 8.52 204.04 92 155.74 + 5.02 (4) 6.44 178.53 122 148.76 ± 9.83 (4) 13.21 193.37
Phleum pratense
6 199.02 ± 6.67 (4) 6,69 229.29 16 190.87 + 5.41 (4) 5.66 215.43 23 175.93 + 2.33 (4) 2.64 186.49 29 173.25 + 1.59 (4) 1 .82 180.44
Achi 1 lea mi 1 lefol iurr )
+ 6 210.84 3.75 (4) 3.55 227.87 16 213.11 + 15.29 (4) 1 .43 282.52 23 174.18 2.72 (4) 3.11 186.48 29 189.35 + 7.40 (4) 7.81 222.95 62 160.91 + 4.81 (4) 5.97 182.75 231
Table 53. CContinued).
Species and Days X dpm t S.E. Coefficient X dpm + 99 % Post-Application (Number Subsamples) of Variation Confidence (one-tai I t d i s tri buti on)
AchiI lea millefo!ium ■b 92 166.36 3.88 (4) 4.65 183.98 122 167.56 + 2 . 1 1 (4) 2.52 177. 14
o 1 i dago juncea
+ 6 161.27 2.94 (4) 3.64 174.61 + 16 143.75 0.91 (4) 1 .26 147.89 23 184.24 4- 3.75 (4) 4.06 201.26 29 172.12 + 9.56 (4) l.l 1 215.50 62 159.91 •f 9.99 (4) 1 .25 205.27 92 195.71 + 7.1 1 (4) 7.26 228.00 122 181.85 + 15.40 (4) 1 .69 251.77
Ci rs i um arvense
+ 6 198.05 36.23 (4) 3.66 362.53 16 229. 16 + 8.51 (4) 7.42 267.80 23 173.28 + 3.02 (4) 3.48 187.00 29 152.80 + 2.81 (4) 3.67 165.56 62 146.39 + 2.81 (4) 3.84 159.15 92 146.08 i 3.68 (4) 5.03 162.79
Daucus carota + 6 263.00 16.48 (4) 1 .25 323.10 16 312.60 + 42.68 (4) 2.73 506.38 23 222.78 + 20.34 (4) 1 .83 315.il 29 187.28 + 18.29 (4) 1 .95 270.31 62 164.23 + 2.52 (4) 3.06 175.67 92 184.92 + 8.71 (4) 9.41 224.46 122 172.18 ± 3. 1 1 (4) 3.61 186.30
Pastinaca sativa + 6 242.86 13.98 (41 1 1 .51 306.34 16 2 0 1 . 6 8 + 12.76 (.4) 12.64 259.59 23 198.66 4* 4.73 (.4) 4.81 220.04 29 204.99. + 18.20 (.4) 1 .77 287.16 62 213.88 + 3.7! (4) 3.46 230.72 92 195.74 + 4.67 (4) 4.76 216.92 122 178.37 + 6.76 (4) 7.57 207.05 232
Table 53, (Continued).
Species and Days X dpm t S.E. C oefficient X dpm + 99% Post-Application (Number Subsamples) of Variation Confidence (one-tai I t d is tr i but ion)
Aster ericoi des
16 190.82 + 3.27 (4) 3.42 205.67 23 166.37 + 6.42 (4) 7.70 195.52 29 177.47 9.58 (4) 10.79 220.96 62 168.91 + 8.49 (4) 10.05 207.45 92 176.37 + 4.79 (4) 5.43 198.12 122 170.6! ± 13.22 (4) 15.49 230.63
Eri geron philadelph icus
16 185.33 + 13.73 (4) 14.81 247.66 23 199.61 Hh 10. 15 (4) 1 0 . 16 245.69 29 184.68 + 2.89 (4) 3. 12 197.78
Vernon i a noveboracens i s
62 174.78 ± 3.76 (4) 4.30 191.85 92 232.61 ± 11.26 (4) 9.68 283.74 Plantago IanceoIata
92 163.74 ± 7.30 (4) 8.90 196.85 233
Table 54. Background radiation levels for invertebrate species collected during 1968 and 1969 on the Urbana Wildlife Area.
Species X dpm i S.E. Number of Coeff icient Subsamples of Variation
Gry11 us pennsy 1 van i cus
I96B 32.48 ± 1.50 8 13.08 1969 30.66 ± 0.73 12 8 . 2 2
Me 1anop1 us f ernur-rubrum
1968 37.98 + 1.01 9 7.95 1969 38.39 + 0.85 12 7.66
Hadrobunus sp.
1968 31.65 ± 0.45 10 4.51 1969 35.29 ± 0.84 8 6.74
Parajulus sp.
1968 42.47 ± 1.67 10 12.44 1969 39.82 ± 0.54 4 20.04
Deroceras sp.
1968 33.52 + 2.04 5 13.66 1969 36.23 ± 3.49 4 19.21
Araneus trifo liu m
1968 29.21 ± 0.67 4 2 .2 1 1969 29.62 + 1.26 4 8.50
Philaenus spurmarius
1968 1969 30.66 ± 1.33 15 12.44
Nemob i us a ll ard i
1968 1969 32.48 ± 0.77 12 8 . 2 2 234
Table. 55. Background radiation levels for the tissues of the short- tailed shrew (BIarina brevicauda) collected during 1968 and 1969 on the Urbana Wi Id Ii fe Area.
Ti ssue X dpm + S.E. Number of Coeff i ci ent Subsamp1es of Variation
Skeletal Muscle
1968 35.67 ± 0.33 24 4.51 1969 35.34 ± 0.41 23 5.69
Heart
1968 117.94 t 5.98 24 25.74 1969 141.75 ± 5.86 24 2 0 . 2 0
Spleen
1968 144.35 t 16.59 20 5! .38 1969 160.43 ± 14.(7 24 43.20
Liver
1968 37.12 + 0.89 24 1 1 .6 6 1969 41.J6 ± 0 .J4 24 16.98
Ki dneys
1968 82.09 ± 4.62 24 27.51 1969 95.04 + 4.67 24 24.01
Lungs
1968 69.02 ± 3.91 22 26.54 1969 68.47 ± I .87 24 13.37
Brain
1968 157.25 t 14.14 22 42. 17 1969 75.99 ± 4.07 24 26.07
Skin and Fur
1968 1969 149.85 ± 12.74 18 36. 14 235
Table 56. Background radiation levels for the tissues of the masked shrew (Sorex ci nereus) collected during 1968 and 1969 on the Urbana WiId Ii fe Area.
T i ssue X dpm ± S.E. Number of Coefficient Subsamp1es of Variation
Skeletal Muscle
1968 37.21 ± 0.49 14 4.97 1969 36.08 ± 1 .8 8 4 10.42
Viscera
1968 32.62 t 0.21 1 1 2.15 1969 34.15 + 1.25 4 7.29
Table. 57. Background radiation levels for the tissues of the meadow vole (Microtus permsyIvanicus), Urbana Wi1dli fo Area, 1969.
Tissue X dpm + S.E. Number of Coeff i ci ent Subsamples of Variation
Skeletal Muscle 32.48 + 0.54 9 5.01
Heart 141.01 + 11.64 9 24.76
Spleen 249.88 + 41.54 8 47.85
Liver 36.11 ± 1.84 9 15.29
Ki dneys 70.72 t 5.21 9 2 2 . 1 1
Lungs 71.24 + 3.27 9 13.75
Brai n 43.28 + 2.95 9 20.51
Skin and Fur 157.66 t 3.81 5 5.41 236
Table 58. Background radiation levels for the tissues of the cottontail rabbit (Sylvilagus floridanus), Urbana Wildlife Area, 1969.
Ti ssue X dpm - t S,E. Humber of Coeff ictent Subsarnp les of Variation
+ Skeletal Muscle 38.33 2 . 12 5 12.38
Heart 32.33 + 0.74 5 5.23
Sp1een 30.57 ± 1 .45 3 8 .2 1
Liver 27.81 + 0.52 5 4. 13
Ki dney 29.59 + 0 . 2 0 5 1.52
lung 32.08 + 0.24 5 1 .71
Bra i n 32.26 + 0.52 5 3.63 in ro Ski n and Fur CO + 5.00 4 6.58 •
Fat frorn Abdominal Cavi ty 33.94 + 0.71 4 4. 18 237
Table 59. Background radiation levels for the tissues of tfie mink (Mustela'vi son).
Tissue X dpm i S.E. Number of Coeff i c i ent Subsamp1es of Variation
Subcutaneous Fat 29.83 i 0.74 4 4.93
Skeletal Muscle 34.52 ± 0.60 4 3.46
Heart 31.12 ± 0.58 4 3.73
Spleen 36.07 + 1 .65 4 9.15
Liver 36.44 t 1 .23 4 6.75
K1dney 39.47 ± 1 .69 4 8.53
Lung 31.08 i 1 .6 8 4 10.81
Bra I n 33.36 ± 0.67 4 3.99
Skin and Fur 147.08 ± 6.31 2 6.05
Submaxi 11ary G1 and 34.51 i 0 . 6 8 4 3.94
Fat from Abdominal CavIty 30.08 ± 0.53 4 3.49
Adrenal Gland 2 0 0 . 1 2 t 56.79 3 49.10 238
Table 60. Background radiation levels for the tissues of the wood mouse (.Peromyscus laucopus) collected during 1968 and 1969 on the Urbana Wildlife Aroa.
Ti ssue X dpm i S.E. Number of Coeff icient Subsamp1es of Variation
Skeletal Muscle
1968 34.82 ± 0.30 17 3. 19 + 1969 33. 15 0.37 6 2.75
Heart
1968 125.10 ± 8.46 18 28.68 1969 142.75 i 15.71 6 26.81
Liver
1968 33.71 + 0.59 14 6.56 1969 32.77 + 0.45 5 3.05 '
Ki dney
1968 87. IB ± 5.67 17 26.77 1969 58.05 + 3.84 5 14.81
Lungs
1968 76.89 ± 1 .52 14 24. 18 1969 78.51 ± 9.08 6 26.89
Brai n
1968 1 0 1 .8 6 ± 6.71 16 26.36 + 1969 50.58 5.04 6 24.43
Skin and Fur
1968 1969 158.07 ± 1.77 ~6 2780 239
Table 61. Background radiation levels for the tissues of the red-winged blackbird (.AgeIaius phoeniccus), Urbana Wildlife Area, 1969.
Ti ssue X dpm i S.E. Number of Coeff i ci ent Subsarnp 1 es of Variation
Breast Muscle 35.13 ± 0.94 4 5.35
Leg Muscle 31.60 ± 0.87 4 5.47
Liver 31.91 + 1.64 4 10.28
Heart 44.97 ± 5.00 4 22.23
Gizzard 31.33 ± 0.42 4 2.64
Lungs 30.74 ± 0.94 3 5.30
Bra i n 33.04 + 0.91 3 4.78
Table 62. Background radiation levels for the tissue of the garter snake (Thamnophis sirtalis), Urbana Wildlife Area, 1969.
Ti ssue X dpm t S.E. Number of Coeff i ci ent Subsarnp1es of Variation
Skeletal Muscle 36.12 i 0.85 4 4.71
Viscera 31.40 1 0.71 4 4.49 240
Table 63. Background radiation levels for the tissues of the ring-necked pheasant CPhasianus colchicus), pen-raised controls, 1969.
Tissue X dpm ± S.E. Number of Coefficient Subsarnp 1 es of Variation
Leg Muscle 32.72 ± 1.05 4 6.42
Breast Muscle 34.49 + 0.61 4 3.85
Heart 3l.lt ± 0.43 4 2.76
Li ver 34.63 ± 5.69 3 28.71
Kidney 29.44 ± 0.63 4 4.28
Gi zzard 33.36 + 0.41 4 2.43
Brat n 32.77 + 0.76 4 4.61
Large Intestine 30.30 ± 0.41 4 3.04
Sma11 1ntesti ne 30.00 + 0.48 4 3. 16 241
Table 64. Background radiation levels for the study pond control flora and fau n a, Urbana Wildlife Area, 1969,
Speci es X dpm i S.E. Number of Coefficient Subsarnples of Variation
Myriophy11um sp. 167.24 t 3.55 4 4.25
Chara sp. 151.33 ± 2.18 4 2.89
Filamentous Alga 151.60 i 2.67 4 3.52
Notonect i dae 35.93 + 1.87 4 10.38
Aeschnidae 31.52 i 0.57 4 3.59
Rana catesbeiana (T adpo1e} 119.66 ± 2.00 4 3.34
Acr i s g ry 11 us 60.01 ± 8.41 4 28.01
Pimephales prornelas 33.48 + 1.46 4 8.69
Rana catesbeiana (Adult)
Skin 32.96 ± 1.31 4 7.95 Li ver 38.69 i 0.80 3 3.56 Skeletal Muscle 33.27 + 0.40 4 2.40