CONTAMINATION OF SURFACE AND GROUND WATER WITH PESTICIDES APPLIED TO COTTON

T. J. Sheets J, R, Bradley, Jr, M, D, Jackson

A contribution of the North Carolina State University Agricultural Experiment Station, The work upon which this publication is based was supported in part by funds provided by the Office of Water Resources Research, Department of the Interior, through the Water Resources Research Institute of the University of North Carolina as authorized under the Water Resources Research Act of 1964,

Project No, A-040-NC

Agreement No. 14-31 -0001 -3233, FY 1971

April, 1972

ACKNOWLEDGEMENTS

We gratefully acknowledge the following individuals for their contribution to this project.

Mr. Warren Bai ley (superintendent, Upper Coastal Pla in Research Station, Rocky Mount, N. C.) and Mr. Wallace Baker (Super i ntendent, Peanut Be1 t Research Station, Lewlston, N, C.) for providIng study sites and assisting in the preparation and maintenance of sl tes, installation of equipment, and sampling.

Dr, Larry A, Nelson for advice on statistical methods,

Mr, Rick E. Dixon, WE l lie L. Jones, Larry D. Phelps, and Phi lip H. Threatt for assistance in preparation and maintenance of sites, installation of equipment, application of pesticides, and collecting and analyzing samples.

Mrs. Billie J. Frazier for her stenographic contribution to the project throughout the period of study.

ABSTRACT

Of the total trifluralin, toxaphene, or methyl parathion applied to cotton plots, less than 1% was recovered in surface runoff. When DDT was applied alone, an average of 2.83% was present in runoff; whereas only about 1% of the DDT from a combination DDT plus toxaphene treatment was found in runoff, Of the DDT, trifluralin, toxaphene, and methyl parathion recovered in runoff, 96, 84, 75, and 12%, respectively, was associated with the sediment fractions. Residues of trifluralin, DDT, and toxaphene persisted in soil from one season to the next. On a percent basis, trifluralin appeared to be more persistent than DbT and toxaphene. A much greater percentage of trifluralin, DDT, and toxaphene remained as residues in the soil than was found in runoff. A high percentage of the DDP, toxaphene, and methyl parathion was not recovered from runoff and soil. Residues of DDT in water from a small pond within one experimental watershed ranged from <0.35 ppb before spraying to 13.4 ppb during the spraying season. Voxaphene residues in pond water varied from <1 ppb before spraying to 65 ppb about mid seasop. Methyl parathion was detected in pond water for two sampling dates. The highest concentration of trifluralin in pond water (1-61 ppb) occurred during a heavy rain 5 days after application. None of the pesticides were detected in we1 1 water.

TABLE OF CONTENTS

Page

Acknowledgments ...... i Abstract ...... ii Table of Contents ...... iii ListofFigures ...... 1 List of Tables ...... 2 Summary and Conclusions ...... 6 Recommendations ...... 10 introduction...... 11 Experimental Procedures ...... 12 Design ...... 12 Cultural Practices ...... 15 Sampling ...... 18 Analytical Methods ...... 19 Results ...... 21 Surface Runoff ...... 21 Soil Residues ...... 26 Pond Water and Sediment ...... 31 Well Water ...... 33 Discussion ...... 33 Li terature C i ted ...... 42 List of Publications ...... 45 Glossary of Terms and Abbreviations ...... 45 Appendix ...... 47 Ll ST OF F l GURES

Figure 1. Map of experimental area at the Upper Coastal Plain Research Station near Rocky Mount, North Carolina.

Figure 2. Map of experimental area at the Peanut Belt Research Station at Lewiston, North Carolina.

Figure 3. Runoff plot showing sheet metal barriers, collection trough, and tank. LIST OF TABLES

Table 1. irifluralin (mg and percent of amount applied) in surface runoff from cotton plots after natural rainfall between the time of application In the spring of 1969 and 1970 and the time sampling was discontinued in late fall or winter.

Table 2. Residues of DBT and toxaphene (mg and percent of amount applied) in surface runoff collected fran 0.0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina, between the time of the first application in 1969 and the time sampling was discontinued.

Table 3, Residues of methyl parathion and toxaphene (mg and percent of amount appl ied) in surface runoff col lected from 0.0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina, between the time of the first application in 1970 and the time sampling was discontinued,

Table 4. Residues of trifluralin in the 0 to 6-inch depth of soil from 0,0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina from 1969 to 1971.

Table 5. Residues of DDP in the 0 to 6-inch depth of soil from 0.0041-acre cotton plots at Rocky Mount and Lewiston, North Carol ina sprayed 12 times during the 1969 season,

Table 6. Residues of toxaphene in the 0 to 6-inch depth of soll from 0.0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina sprayed 12 times during the 1969 season.

Table 7, Residues of toxaphene in the 0 to 6-inch depth of soll from 0,0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina sprayed 12 times during the 1970 season,

Table 8. Residues of methyl parathion in the 0 to 6-inch depth of soil from 0,0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina sprayed 12 times during the 1970 season. -2- Table 9. Concentrations of DDT, toxaphene, and trifluralin in water from the pond at Rocky Mount before and after the 1969 appli- cations.

Table 10. Concentrations of methyl parathion, toxaphepe, and trifluralin in water from the pond at Rocky Mount before and after the 1970 applications,

Table 11. Concentrations of BDF, methyl parathion, toxaphene, and trifluralin in sediment from the pond at Rocky Mount before and after the 1969 and 1970 applications.

Table 12. Concentrations of methyl parathion, toxaphene, and trifluralin in water from wells located in cotton fields sprayed with the three pesticides during the 1970 season (Rocky Noun t s i te) .

Table 13. Concentrations of methyl parathion, toxaphene, and trifluralin in water from wells located in cotton fields sprayed with the three pesticides during the 1970 season (Lewi s ton s i te) . qppendix Table 1. Rainfall, runoff volume, and amount of tri- fluralin in runoff during a 5-month period after application of 1 Ib/A at Rocky Mount in 1969.

Appendix Table 2. Rainfall, runoff volumes, and amount of triflu- ralin in runoff during a 7-month period after application of 1 lb/A at bewiston in 1969.

Appendix Table 3. Rainfall, runoff volume, and amount of triflu- ralin in runoff during an 8-month period after application of 1 lb/A at Rocky Mount in 1970.

Appendix Table 4. Rainfall, runoff volume, and amount of triflu- ralin in runoff during a 6-month period after application of 1 lb/A at Lewiston in 1970. Appendlx Table 5, Ilalnafall, runoff volume, and amount of DQT in runoff (DDT applied alone) during a 3-month period at Rocky Mount after iniriation of the seasonal spray program for insect control,

Appendix Table 6, Rainfall, runoff volume, and amount of DDT in runoff (DDT appl ied alone) during a 6-month period at Lewi ston after initiation of the seasonal spray program for insect control.

Appendix Table 7. Rainfall, runoff volume, a~damount of toxaphene in runoff (toxaphene appl i ed a lone) during a 3-month period at Rocky Mount after initiation of the seasonal spray program for insect control.

Appendix Table 8. Rainfall, runoff volume, and amount of toxaphene in runoff (tsxaphene applied alone) during a 6-month period at Lewiston after initiation sf the seasonal spray program for insect control.

Appendix Table 9, Rainfall, runoff volume, and amounts of DDT and toxaphene in runoff (DDT and toxaphene applied in combination) during a 3-month period at Rocky Mount after initiation of the seasonal spray program for insect control.

Appendix Table 10, Rainfall, runoff volume, and amounts of DDT and toxaphene in runoff (DDT and toxaphene applied in combination) during a 6-month period at Lewiston after initiation of the seasonal spray program for insect control.

Appendix Table 11. Rainfall, runoff volume, and amount of methyl parathion in runoff (methyl parathion applied alone) during a 6-month period at Rocky Mount after initiation of the seasonal spray program for insect control.

Appendix Table 12, Rainfall, runoff volume, and amount of methyl parathion in runoff (methyl parathion applied alone) during a 4-month period at bewi ston after ini tiation of the seasonal spray program for insect control, -4- Appendix Table 13. Rainfall, runoff volume, and amount of toxaphene in runoff (toxaphene applied alone) during a 6-month period at Rocky Mount after initiation of the seasonal spray program for insect control.

Appendix Table 14. Rainfall, runoff volume, and amount of toxaphene in runoff (toxaphene applied alone) during a &-month period at Lewi ston after initiation of the seasona 1 spray program for insect control.

Appendix Table 15. Rainfall, runoff volume, and amounts of methyl parathion and toxaphene in runoff (methyl parathion and toxaphene applied in combination) during a 6-month period at Rocky Mount after initiation of the seasonal spray program for insect contra1 .

Appendix Table 16. Rainfall, runoff volume, and amounts of methyl parathion and toxaphene in runoff (methyl parathion and toxaphene applied in combination) during a 4-month period at Lewiston after initiation of the season31 spray program for insect control, SUMMARY AND CONCLUSIONS

The objectBves of this research were (a) to study movement of trifluralin, DDT, toxaphene, and methyl parathion in surface runoff arising from natural rainfall in cotton fields sprayed with the four pesticides, (b) to determine residues of the pesticides in soil at several times after application, (c] to follow the level of contamination of a farm pond with the pesticides applied to cotton fields in a small watershed, and (d) to determine if water in wells (depths of 4, 6, 8, 10, and 12 feet) within fields treated with the pesticides became contaminated. The study was conducted at ewo locations for 2 years,

Collection tanks and specially designed catchment devices were installed for each of 16 plots (eight at each of two locations). Cotton culture and pesticide applications were similar to practices of North Carolina farmers, Trifluralin, DDT, and toxaphene were used the first year; for second year applications methyl parathion was substituted for DDT, Trifluralin was applied at I lb4A a~d incorporated before planting cotton. The insecticides were applied to the foliage between mid July and mid September, At each of 12 applications per season, the rate of DDT or methyl parathion was 1 lb/A and that for toxaphene was 2 lb/A.

Sediment in runoff was separated from water by filtration, and the two components were analyzed separately. Methyl parathion was determined in crude extracts by flame-photometric gas chromagography; trifluralin, DDT, and toxaphene were measured by electron-capture gas chromatography in the same extracts after cleanup.

Of the 1 Bb/A of trifluralin applied to cotton plots, less than 1% was detected In surface runoff during sampling periods of 5 to 8 months. Qf the total DDT applied during the spray season (12 Ib/A), 3.12% or less was recovered in runoff, Less DQT was found in runoff from plots that received DDT in combination with toxaphene than was found in runoff from plots that received DDT a lone, even though the same amount of DDT was appl ied in both treat- ments, The oily toxaphene formulation appeared to act as a sticker for DDT so that less was washed from cotton plants when the two insecticides were applied in combination. Residues of toxaphene and methyl parathion recovered in runoff were less than 1 and 0.25%, respectively.

Trifluralin persisted in the soil from one growing season to the next qt both locations. Carryover was greater at bewiston than at Rocky Mount. For example, on April 27, 1971, about 1 year after the second application of 1 lb/A, 0.10 ppm was present in plot soil from Rocky Mount whereas 0.44 ppm were present in Lewiston plot soil. This difference can be attributed in part to the organic matter levels in two soils (0.7% at Rocky Mount and 1.6% at bewiston). Other soil properties were probably involved also.

Except for one treatment on one sampling date, residues of DDT in soil were much higher than those of toxaphene, even though twice as much toxaphene as DDT was applied. Residues of DDT remained about the same from the sampling date following the last application until the samp 1 i ng date the next spr i ng, whereas toxaphene res i dues declined during this time. Significantly less DDT was recovered from soil of plots where DDT was applied in combination with toxa- phene, compared to plots where DDT was applied alone, These data are consistent with those for surface runoff and suggest indirectly that more DDT remained on the cotton foliage in the presence of toxaphene than in its absence, If DDT is retained longer on the leaves, processes such as photodec~mp~~itionand volatilization may reduce the total residue on the plot.

The only residues of methyl parathion in soil that exceeded the lowest detectable limit of 0.10 ppm were those for the methyl parathion alone treatment sampled during and immediately after the spray season, Thgse data suggested indirectly that, in the presence of toxaphene, methly parathion was retained longer on the foliage than in its absence. This observation and the identical result with DDT and toxaphene combinations prompted experiments in 1971 which demonstrated conclusively that methyl parathion applied in combination with toxaphene persisted on or in cotton leaves under field conditions at much higher concentrations than methyl parathion applied alone.

A much greater percentage of tri f 1 ura 1 l n, DDT, and toxaphene remained as residues in soil than was found in runoff. When residues in soil and in runoff were summed, a very low percentage of the toxaphene was recovered. in contrast, higher percentages of DDT and trifluralin were recovered, but in no case did total recovery approach the total amounts applied. Total recovery from both sources was least for methyl parathion (less than 1% of the total applied).

The highest concentrations of trifluralin in pond water over the 2-year study occurred within 2 months of application and declined thereafter. The greatest single recovery of trifluralin from pond water (1.61 ppb) occurred after a heavy rain on May 20, 1969, about 5 days after application to the watershed area. The 96-hr median tolerance limit for triflurain is 58 ppb for bluegill.

Significant concentrations of DDT and toxaphene were recovered from pond water following several rains in 1969. Levels of these pesticides, notably toxaphene, were high when intense rains immediate ly followed application, Toxaphene concentrations ranged from 2.9 to 65.2 ppb during and immediately after the 1969 spray season. I n a 1 l samp les except one, levels of toxaphene recovered from pond water were more than four times those of DDT and equaled or exceeded the 96-hr median tolerance l imi t for bluegi 11 (3.5 ppb). During 1970 when total rainfall was much less, the highest concen- tration of toxaphene found in pond water was lower than the lowest concentration found in 1969. Although toxaphene does not pose an obvious chronic environmental hazard, it is an acute hazard to aquatic fauna in ponds and small streams where high percentages of the water- sheds are treated and where transport of large volumes of sediment in surface runoff is likely, Detectable levels of methyl parathion were found in pond water on only two sampling dates in 1970. The highest concentration (3.5 ppbj was approximately 1/700 of the 96-hr median tolerance 1 imi t of 2,400 ppb for bluegill,

Except for cpncentrations of 0.08 and 0.11 ppm in pond sediment on July 15, 1969, trif luralin residues were just above or below the detectable limit (0.01 ppm) throughout the 2-year study. DDT concen- trations ranged from less than 0.14 to 2,01 ppm in pond sediment. Data were variable, and there was no apparent relation between concentration and time of application. The level of methyl parathion was below the detectable limit on all sampling dates (1970). Poxaphene levels were higher in 1969 than in 1970; the highest concentration was found in a sample collected about 2 weeks after the last application in 1969.

Contamination of the wells in 1969 invalidated data for the entire year. In 1970 analysis of a large number of well-water samples showed no detectable levels of the pesticides.

This research is being continued through support from other sources, the initial endeavor being made possible by support from the Office of Water Resources Research, Department of the Interior, through the Water Resources Research Institute of the University of North Carol ina, 1. When toxaphene, DDT, and related pesticides are applied to row crops, consideration should be given to designing small settling basins through which surface runoff from treated watersheds would flow allowing suspended particulate matter to which pesticides are adsorbed to settle out prior to entering aquatic systems. Such basins could be ditches or dikes along the lower sides of fields between the edge of fields and ponds and streams, the main purpose being to retard flow so as to allow suspended particulate matter to settle,,

2, Research should be undertaken to develop specific compounds that can be added to spray mixtures to increase retention of pesti- cides on the plant (target site) and thereby reduce amounts in surface runoff. Through increasing persistence of insecticides on plant surfaces, fewer applications and perhaps lower rates would be required for control of insect pests; and consequently less total insecticide would be needed,

3. These and similar data on other pesticides should be utilized in developing a model of pesticide movement in surface runoff and retention in soil. When combined with inputs of percent- age of a watershed treated, number of applications, and frequency and volume of rainfall, an estimate of the contribution of pesticide use to environmental pollution could be calculated for any set of condi tions.

4. Restrictions on use of toxaphene should be limited to those use patterns likely to result in movement or application of large volumes of the insecticide into aquatic systems.

5. When significant contamination of a pond or stream with toxaphene, DDT, or related compounds is likely to occur, consideration should be given to adjusting crop rotation schemes so as to minimize the percentage of a watershed treated during any one season. The proposed model (recommendatiol~3) could be used to calculate the maximum percentage of a watershed that should be treated.

The distribution of pesticides in aquatic ecosystems and their effects on animals of different trophic levels in food chains have been discussed (Cope 1965, Newsom 1967, Sheets --et al, 1970, U. S. Department of Health, Education, and Welfare 1969). Pesticides are transported in surface water, partly as adsorbed molecules on suspended clay and organic colloids alley 1966), from sites of application into streams, ponds, and lakes, Amounts in runoff depend on climatic factors such as frequency, intensity, and duration of rain; soil physical properties that influence runoff; and the chemical and physical properties of the pesticides (Bailey 1966, Epstein and Grant 1968, Kunze 1966, Lichtenstein --et al. 1966, Nicholson 1969). The persistence and movement of pesticides through soils will affect the amount of residue in runoff as well as that in the surface soil. Factors affecting the movement or persistence in the soil have been reviewed by several investigators (Alexander 1965, Bai ley and Whi te 1965, Edwards 1964, Kunze 1966, Legrand 1966, Wheatly 1965).

Quantitative data on movement of pesticides from crop lands is limited, Epstein and Grant (1968) studied chlorinated hydrocarbon insecticides in runoff water as affected by crop rotation of potato (Solanum tuberosum L.), oats (~vena-sativa L.), and sod. Barnett --et al. (1967) determined losses of 2,4-D from cultivated fallow land, and White --et al. (1967) measured atrazine movement in surface runoff from fallow land after simulated rainfall. Trichell --et al. (1968) compared lo~sesof dicamba, 2,4,5-T, and picloram in runoff from sod and fallow s~il, Experiments have not been conducted on movement of pesticides in runoff from cotton fields, although this crop receives more insecticide applications than any other. - 11 - The objectives of this study were (a) to study movement of DDT, methyl parathion, toxaphene, and trifluralin in surface runoff arising from natural rainfall in cotton fields sprayed with the four pesti- cides over a 2-year period, (b) to determine resldues of the pesticides in soil at several times after application, (c) to follow the level of contamination of a farm pond with the pesticides applied to cotton fields in a smal l watershed, and (d) to determine if water in wells within fields treated with the pesticides became contaminated. Trifluralin was selected for this study because it is a major herbicide for weed control in cotton in the Southeast. Similarly, DDT, methyl parathion, and toxaphene are the major insecticides for cotton insect pest control in the United States of America, and DDT has been impli- cated repeatedly as an environmental pollutant.

Summary tables for pesticides in runoff and all data for residues in soil, well water, and pond water and sediment are included in the body of the report, Detail data of rainfall, runoff volumes, and amounts of pesticides in runoff for each storm are recorded in the Append i x.

EXPER l MENTAL PROCEDURE

De,sign, The study was conducted near Rocky Mount, North Carolina, on a Norfolk loamy sand and near Lewiston, North Carolina, on a Goldsboro sandy loam. The pH, cation exchange capacity, and organic matter content of the surface soil at Rocky Mount averaged 5.2, 2,O me/100 g, and 0.7%, respectively. At bewiston the pH was 5.9, the cation exchange capacity 3,9 me/100 g, and the organic matter content 1.6%. Eight plots were established at each location (Figures 1 and 21, Plots were 6 feet wide and 30 ft long with sheet metal barriers along the sides and upper end and a sill plate and metal collection device at the lower end. The metal barriers extended 4 inches above and 8 inches below the soil level. The sill plate was embedded to a depth of 1 faot. Runoff from the plots moved through UPPER COASTAL PLAIN RESEARCH STATION

Field 2A (2.5 acres)

No cultivation Special crops

Pond / (0.5 acres)

Field 15

I Field 1 (1.5 acres)

Figure 1, Map of experimental area at the Upper Coastal Plain Research Station near Rocky Mount, North Carolina, metal collection troughs into 55-gal metal tanks, which were buried to ground level (Figure 3). Plot slope was approximately 4% at Rocky Mount and 2% at Lewiston,

After installation of catchment tanks and collection troughs, two rows of cotton were planted within and parallel to the long axis of each plot and parallel to the slope. Experimental plots were separated by three border rows to minimize cross contaminati~n through drift of the pesticides,

At both locations two wells each were drilled to depths of 4, 6, 8, 10, and 12 ft In cotton fields sprayed with the pesticides (Figures 1 and 2). Each well was lined with a continuous steel pipe (h jnches i.d,) so that water could enter the casing only by penetrating to the designated depth.

A 0,5-acre pond was located in the experimental watershed at the Rocky Mount site (~igure 1). Approximately 60% of the water- shed supplying the pond was planted to cotton in 1969,

Cultural Practices. In 1969 the soil in each experimental area Nas tilled and trifluralin was applied at 1 Ib/A and incor- porated prior to installation of the metal barriers, During 1970 trifluralin at the same rate was applied to soil within plots and incorp~ratedwith a rototiller immediately thereafter without removing metal barriers. Treatment dates were May 15, 1969 and May 8, 1970 for the Rocky Mount site and May 29, 1969 and May 8, 1970 for bewiston.

During both years insecticides were applied as foliage sprays to cotton plants within plots 12 times at approximately weekly intervals from early July until September, Aqueous emulsions of BBT or methyl parathion wes appl ied at 1 lb/A per appl !cation, and the toxaphene rate was 2 lb/A per application. Insecticide applications were July 11, 15, and 21, August 7, 12, 18, 22, and 27, and September 1, 5, 8, and 12 for both locations in 1969. In Figure 3, Runoff plot showing sheet metal barriers, collection trough, and tank. 1970 applications were made on July 13, 18, 24, and 30, August 6, 11, 18, 21, 25, and 31, and September 5 and 10,

The pesticide application scheme Is shown below:

Plot 1969 1970 No. In~ecticide Herbicide Insecticide Herbicide

Fluometuron Fluometuron DDT Trifluralin M. P. Trifluralin Toxaphene Fluometuron Toxaphene Fluometuron DOT + Tox. Trifluralin M.P. + Tox. Trifluralln Trifluralin Trifluralin DDT Fluometuron M. Po Fluometuron Toxaphene Trifluralin Toxaphene Trifluralin DDT + Tox, Fluometuron M.P. + Tox. Fluometuron

The scheme was identical for both locations, but plot positions were randomized within replications. The design was a randomized block, Fluometuron was applied to control weeds in plots not treated with trifluralin so that runoff would not be impeded by weed growth.

At the Rocky Mount site about half of the watershed area out- side of the experimental plots (the fields where the wells were located) received 13 appl ications of DDT plus toxaphene (1 plus 2 lb/A) in 1969; most of the remainder of the watershed received 16 applications of methyl parathion plus toxaphene (0.75 plus 3.0 Ib/A), In 1970, the two cotton fields with the wells were sprayed 11 times with 0.75 lb/A of methyl parathion plus 3.0 lb/A of toxaphene. The remainder of the watershed was not planted in cotton in 1970,

At the Lewiston site the wells were located in a 3.5-acre field adjacent to the surface runoff plots. This field was planted to cotton in both years, and the cotton was sprayed 13 times in 1969 with DDT plus toxaphene (1 plus 2 lb/~)and 11 times in 1970 with methyl parathion plus toxaphene (0.75 plus 3.0 Ib/A). Sampl i ng. Samples of surface runoff were taken wi thi n 24 hours after each rain (except where indicated in the tables) if the runoff volume in the storage tanks equaled or exceeded 6 Iirers. The following procedure was followed For each plot: water depth was measured for calculation of total runoff, sediment and water were thoroughly mixed, a 4-liter sample was collected, and tanks were pumped and cleaned. At the laboratory runoff samples were stored temporar i ly at 4 C and then f i l tered through fi l ter paper (E & Q 68 3) in a Buchner funnel to separate sediment and water, Sediment was stored at -18 C. Extraction of water began within 24 hours after collection.

Preliminary tests showed that the maximum retention of DDT and toxaphene by the filter paper ranged between 7 and 9% of the total in solution. When adsorption to sediment and solubility in water of these insecticides are taken into consideration, the correction for re,tent i on by filter paper would not exceed 1% of the total DDT and 3% of the total toxaphene in the runoff. Therefore, the data are presented without correction.

A so %1 sample consisting of 20 randomly selected cores (2.5 by 15 cm) was collected about 3 months before the first application of insecticides. Samples were taken from all plots several times after application each year, Ten soil cores 2.5 em in diameter were taken at random from the 0 to 15-cm depth within each plot and were composited for analysis. The samples were transported to the laboratory and stored at -18 6.

Well water samples were taken according to the following procedure: Wells were pumped 1 to 2 days before each sampling date so that the water removed for analysis would represent sol l water ?resen% at the sampling time. The 12-ft wells were pumped for several minutes to assure a fresh water supply. A 4-1 i ter sample of water was taken from each we 1 containing an adequate volume for sampling on each sampling date. Well water samples were collected with a cylindrical sampling dev ce (3 inch Hod.) of 1 liter capacity which was lowered into the wells by a rope attached at the upper end. The sampling device was open at the upper end and contained a ball- valve at the bottom to allow entry of water but to prevent loss as the device was wi thdrawn from a we l I.

A 4- I i ter sample of water was taken From the pond at Rocky Mount at the same time that runoff samples were collected, Pond sediment was sampled at the same time as plot soil, which was less frequent than for the pond water, However, sampling of pond sediment continued into the next season.

Analytical Methods. Trifluralln, BDT, methyl parathion, and roxaphene were extracted from water by the same procedure, Approxi- mately 4 liters of water were weighed in a 9-liter glass bottle with a ground glass stopper. Five hundred ml of a solution of -n-pentane and diethyl ether (a:] v/v) were added to the bottle, and the contents were shaken vigorously for 15 min on a mechanical shaker. Then the extraction solvent was siphoned into a 2-liter container, and the extraction was repeated 3 times for 5 min each time with an additional 500 ml of extraction solvent, The extracts from a single sample were combined, and the combined extract was filtered through a layer of anhydrous sodium sulfate into a Kuderna-Banish evaporating flask. The volume was reduced to about 10 ml for column chromatography. Without further cleanup approximately 5 pliters of the solution were removed (from 1970 samples only) for determination of methyl parathion by flame-photometric gas chromatography. The flame-photometric detector was attached to a MT-220 gas chromatograph. The 0,64 by 183-cm U-shaped glass column was packed with 4% SE-30 and 6% QF-l on Gas Chram Q (60/80 mesh), Temperatures of the injection port, column oven, and detector were 220, 180, and 200 C, respectively, The flow rate of nitrogen was 100 cc/min, Methyl parathion concentrations were determined from peak height measurements.

The sediment and filter paper from a runoff sample or approxi- mately 40 g of air-dry soil or pond sediment was extracted in a Soxhlet apparatus for 4 hours with 150 ml of a solution of isopropanol and benzene (2: 1 v/v) . After extraction, i sopropano l and benzene were evaporated (to dryness) on a rotary flash evaporator, and the residue was dissolved in 10 ml of -n-hexane in preparation for column chromatography. At this point a small portion (microliter quantity) was removed (for 1970 samples only) for determination of methyl parathion,

Cleanup was identical for water, sediment, and soil. All of the extracts were transferred to a 10-cm column of activated Florisil, which was topped with a I-cm layer of anhydrous sodium sulfate. The insecticides were eluted with 200 ml of 6% diethyl ether in petroleum ether. The volume of the column eluate was reduced, and -n-hexane was added to make the final volume to 10 ml. The solutions were ready for gas chromatography.

The insecticides were measured with a Varian Aerograph (Series 3200) gas chromatograph equipped with an electron-capture (triti um foil) detector. The 0.3 by 183-cm coiled glass column was packed with 4% SE-30 and 6% QF-1 on Gas Chrom Q (60/80 mesh). Temperatures of the injection port, column oven, and detector were 220, 165, and 205 C, respectively. The flow rate of nitrogen was 80 cc/min.

The amounts of p,p'-DDE, o,p-DDT, p,ps-DDY, and p,p'-DDD were derived from gas chromatographic traces by the triangulation method. Values for these derivatives were summed and are presented as DDT. Poxaphene was determined from the heights of three major peaks with elution times different from those of DDT isomers. In samples containing both DDT and toxaphene, the latter was determined in the same way as in samples without DDT; and BDT derivatives were estimated by triangulation from the peaks superimposed on the toxaphene curve.

Recoveries of known amounts of the pesticides added to water and soil immediately before extraction are as follows: Recoveries from water.

- -- , Number Concn Recovery Recovery o f added average range Pesticide samples (PP~) (%) (%I

Methyl parathion 10 1 .25- 500 94 78- 1 1 1 Trifluralin 13 0.10-10.0 8 3 67-91 Toxaphene 16 0.50-75.0 9 7 82-1 11 p, p'-DDE 4 0.50-1.0 8 5 7 3-86 o, p-DDT 4 0.50-1.0 8 0 67-96 pr p'-DDD 4 0.50-1.0 94 79- 107 p,ps -QDY 4 0.50- 1 .O 107 86- 124

Recoveries from soil.

------Number Concn Recovery Recovery o f added average range Pesticide samp 1 es ( PP~ (%I (%) - --

Methyl parathion 8 0.08-0,40 90 61-101 Trifluralin 3 0.12-0.50 100 95- 105 Toxaphene 3 0.25-0.60 95 94- 96 p, p' -DDE 3 0.08-0.25 101 95- 108 0,p-DDT 3 0.38-1.25 97 93-103 p, p' -DDT 3 0.75-2.50 96 88- 102

RES U LTS

Surface Runoff. Of the total trifluralin applied to cotton plots in 2 years at two locations, less than 1% was detected in surface runpff during sampling periods of 5 to 8 months after application (Table 1; Appendix Tables 1, 2, 3, and 4). Total trifluralin in runoff exceeded 0.5% at one locafi~nduring 1 year; the high value was 0.76% at Lewiston in 1970. The interaction, locations years, was significant at the 0.01 level. Table 1. Trifluralin (mg and percent of amount applied) in surface sun- off from cotton plots after natural rainfall between the time of application in the spring of 1969 and 1970 and the time sampling was discontinued in late fall or winter.

Total time Total of sampling ~atera sedimenta runoff" Location Year (days) (mg) (%I (mg) ( %)

RockyMount 1969 210 1.55 0.08 7.39 0.39 8.94 0047

Lewi s ton

LSD; locations x years 0,05 0,30 2.30 2.52 0.91 0.42 3,22 3*54 C V % 13 19 18

a Differences between locations and between years were not significant at the 5% probabi 1 i ty level.

Residues of DDT and toxaphene in surface runoff from cotton plots are shown in Table 2, Differences between locations were not slgni- ficant. When DDT was applied alone, 2.55 and 3.12% of the total DDT applied at Rocky Mount and Lewiston, respectively, was recovered from surface runoff during the sampling periods. Less DDT was recovered in runoff from plots to which DBT was applied in combination with toxaphene than was recovered in runoff from plots where DDT alone was applied, even though the same amount of DDT was applied to both plots. Of the DDT recovered, about 96% (average of locations and treatments) was associated wi th sediment col lected on f i 1 ter paper, and 4% was in the f i l trate (water), .- m * m- a, - Xa, c a,- >a, > m sr -a, 6- a > mo wo w *- a, a, uxu .-- 6w6 am m m.- u a L m~ om n %e >wns

z 0- aua m e xwm 0 s QUW (LT tn D I %

lb E't 0 p 0 A- cn me- 13 Pa, xu SOU uo-*irQ @me. w a,> L% mr L+JLO* Less than 1% of the total toxaphene applied as a foliage spray to cotton plants was recovered from surface runoff (Table 2). Of that recovered, about 75% was associated with sediment and about 25% was in the filtrate. More toxaphene was recovered from plots treated with the combination of DDT and toxaphene than from plots rreated with toxaphene alone. This difference was significant only for total toxaphene recovered,

The cumulative totals for DDT in surface runoff illustrate the large difference between the DDT recovered from the DDT-only treatment and the amount recovered from the combination treatment (compare results in Appendix Tables 5 and 6 to those in Appendix Tables 9 and 10).

Concentrations of DDT and toxaphene in runoff varied widely among samplings (~ppendixTables 5, 6, 7, 8, 9, and 10). For example, on one plot at Rocky Mount the DDT concentrati~nranged from a low of 131 ppb to a high of 1,180 ppb (values for individual plots are not shown In tables).

The amount of methyl parathion recovered in runoff over the sampling period in 1970 varied from a low of 0.01% of the amount appl ied to a high of 0.25% (Table 3), About 12% of the methyl parathion in runoff was associated with sediment. The difference between locations was significant for methyl parathion in water, sediment, and total runoff,

The average amount of toxaphene recovered in runoff in 1970 was approximately 29% of that recovered in 1969. Amounts in 1970 ranged from 0,08% of the amount applied for the toxaphene alone treatment at Rocky Mount to 0.22% for the combination treatment at Lewiston (Table 33. About 75% of the toxaphene recovered in runoff in 1970 was associated with the sediment fraction. The difference between locations was significant for toxaphene in water but not for sediment or total runoff. Rainfall, runoff volumes, and cumulative amounts of methyl parathion and toxaphene in runoff for 1970 at both locations are given in Appendix Tables 11, 12, 13, 14, 15, and 16, r a, u r a- a, r - a n.- m ru x a 0 0 cr L n L *'+-0 Ln U a, r r m u + urc 0 mom I= m3m.- ULh

u .-emu .- m a, .- .- ffl E U-J ., 0 -0 L a, a,a,L -ua, ma3 ?"m a,ru L .- -0 Soil Residues. Amounts of trifluralin residues present in soil taken from plots several times after application in 1969 and 1970 are shown in Table 4. Trifluralin persisted in the soil from one growing season to the next at both locations. The carryover was greater at Lewiston than at Rocky Mount. For example, on April 27, 1971, about 1 year after the second application of 1 Ib/A, 0.10 ppm was present in plot soil from Rocky Moupt whereas 0,44 ppm were present in Lewiston plot so; 1,

Table 4. Residues of triflural in in the 0 to 6-inch depth of soi l from 0,0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina from 1969 to 1971.

Appl ication Samp 1 i ng Lewi s ton timea date (ppm) (I b/A) (%)

1969 ~uly15, 1969 0,30 0.60 60 0,42 0.84 84 Sept, 23, 1969 0,21 0-42 42 0.38 0.76 76 Mar. 24, 1970 0.13 0.26 26 0.37 0.74 7'4

June 2, 1970 0.40 0.80 80 0.56 1.12 112 ~uly14,1970 0.22 0.44 44 0.34 0.68 68 Aug.25, 1970 0.16 0.32 32 0.44 0.88 88 Sept. 17, 1970 0,18 0.36 36 0.32 0.64 64 Rec. 2, 1970 0.16 0.32 32 0,37 0.74 74 Apri 1 27, 1971 0.10 0.20 20 0,44 0.88 88 a~pplicationdates: Rocky Mount - May 15, 1969 May 8, 1970 Lewi ston - May 29, 1969 May 8, 1970

Except for one treatment on one sampling date, residues of BDT in soil were much higher than those of toxaphene, even though twice as much toxaphene as DDT was appl i ed (Tables 5 and 6). At Rocky Table 5. Residues of DDT in the 0 to 6-inch depth of soil from 0.0041- acre cotton plots at Rocky Mount and bewiston, North Carolina sprayed 12 times during the 1969 season.

a Insecticides applied Rocky Mounta Lew i s ton Samp 1 i ng DDT Tox . date (lb/A) (lb/A) (PP~ (Ib/A) (%) (ppm) (1 b/~) (%)

a Date means were significant at the 1% probability level. The compari- son of DDT alone versus DDT plus toxaphene over all dates was significant at the 5% level, The date versus spray treatment inter- action was not significant,

Mount residues of DDT remained about the same from the sampling date following the last application (September 23, 1969) until the sampling date the next spring (March 24, 19701, whereas toxaphene residues declined appreciably during this time. Such trends were not evident for Lewiston. Significantly less DDT was recovered from soil of plots where DDT was applied in combination with toxaphene, compared to plots where DDT was applied alone, Table 6. Residues of toxaphene in the 0 to 6-inch depth of soil from 0.0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina sprayed 12 times during the 1969 season.

Insecticides applied Rocky ~ount~ ~ewi s tona Samp 1 i ng DDT Tox . date (Ib/A) (Ib/A) (ppm) (1 b/A) (%) (ppm) (Ib/A) (%)

a Date means were significant at the 1% probability level. The comparison of toxaphene alone versus toxaphene plus BDT over all dates was not significant. The date versus spray treatment inter- action was not significant.

Toxaphene was present in soil samples collected June 2, 1970 in amounts ranging from 0.6 to 1,4 lb/A (Table 6). These residues persisted from the year before and amounted to 2 to 6% of the total applied during 1969. The carryover from the 1969 season contributed to the relatively high recoveries In soi 1 samples taken July 14, 1970, the day after the first 1970 application (Table 73, Although 24 lb/A were appl led dur i ng the 1970 season (in addi t ion to 24 1 b/A i n 19691, residue levels in the soil exceeded the individual application rate of 2 lb/A on only one occasion near the end of the spray season. In April 1971, toxaphene residues ranged from 0.6 to 1.0 lb/A.

Table 7. Residues of toxaphene in the 0 to 6-inch depth of soil from 0.0041-acre cotton plots at Rocky Mount and Lewiston, North Carolina sprayed 12 times during the 1970 season.

------Insecticides applied Rocky Mount Lewi ston Sampl i ng M. P. Tox . date (lb/A) (lb/A) (ppm) (1 b/A) (%) (ppm) (I b/~) (%)

KO. 1 0.4 0.5 Methyl parathion was below the detection limit of 0.10 ppm in all soil samples from the Rocky Mount site (Table 8). However, at hewiston positive values were obtained for the methyl parathion alone treatment on the three samplings that Sell within or immediately after the spray period, The residue level in one replication of the methyl parathion alone treatment at Lewiston on September 17, 1970 was 23.4 ppm; the level in the other replication was less than 0.10 ppm, the average of the two being 11.7 ppm. This value was unusually high, and coatami- nation of the sample was suspected.

Table 8. Residues of methyl parathion in the 0 to &inch depth of soil from 0.0041-acre cotton plots at Rocky Mount and bewiston, N, C. sprayed 12 times during the 1970 season.

------insecticides applied Samp 1 E ng M. P. "hx . Rocky Mount Lewi ston date ( 1 b/A) ( 1 b/A) ( PP~ CPP~

a One sample of two which were averaged for this mean was below the limit of detection (0,IO ppm). Therefore, sample contamination may have contributed to this high value. Pond Water and Sediment. The highest concentration of trifluralin in pond water (1.61 ppb) over the 2-year study occurred after a heavy rain on May 20, 1969, about 5 days after application to the watershed area (Table 9). Concentrat ions decl ined thereafter to near the detection level of 0.05 ppb in early October. In 1970, the hlghest concentration found in pond water was 0.47 ppb on June 23 (Table lo),

Table 9. Concentrations of DDT, toxaphene, and trifluralin in water from the pond at R~ckyMount before and after the 1969 appl ications.

Sampl i ng DDT Tox . Trifluralin date (PP~) (PP~) (PP~) Table 10. Concentrations of methyl parathion, toxaphene, and tri- fluralin in water from the pond at Rocky Mount before and after the 1970 applications.

Samp 1 i ng M. P. Tox , Trifluralin date CPP~) ( PP~) hb]

Significant concentrations of DDT and toxaphene were recovered from pond water at Rocky Mount following several rains in 1969 a able 91, Levels of these pesticides, especially toxaphene, were high when intense rains immediately followed application, The concentration of toxaphene in pond water exceeded that of DDT in all samples except the one collected September 21, $n all other samples the level of toxaphene was more than four times that of DDT. In 1970, toxaphene concentrations in pond water exceeded the detectable level on two sampling dates only. The highest concen- tration in 1970 (2.5 ppb) was lower than the lowest concentration found in 1969 (2.9 ppb) (Tables 9 and 10).

Detectable levels of methyl parathion were found in pond water on two sampling dates in 1970, and these dates were the same dates that toxaphene was detected. Except for concentrations of 0.08 and 0.11 ppm in pond sediment sampled July 15, 1969, trifluralin residues were just above or below the delectable limit (0,01 ppm) throughout the 2-year study (Sable 11). DDY concentrations ranged from less than 0.14 to 2,09 ppm in pond sediment. Data were variable, and there was no apparent relation between concentration and time of application. Analytical values for methyl parathion in pond sediment were less than 0,10 ppm for all samples. Toxaphene levels were higher in 1969 than in 1970; the highest concentration (2.79 ppm) was found in the sample collected about 2 weeks after the last application in 1969 (Table 11).

Well Water. Residue data for well water samples are not shown for 1969. Obvious contamination of the sampl ing devices and the wells was detected in late 1969, invalidating the data for the entire year.

Special care was taken during 1970 to prevent contamination of the wells and the sampling devices. Analysis of a large number of well- water samples collected during 1970 showed no detectable levels of methyl parathion, toxaphene, or trifluralin at either location (Tables 12 and 13).

DISCUSSION

The amount of trifluralin moved in runoff from plots was about equal for the two locations in 1969 (8.94 mg for Rocky Mount versus 8.72 mg for Lewiston). At Rocky Mount the amount transported was less in 1970 than in 1969, whereas at Lewiston the amount moved was greater in 1970 than in 1969. Thus, approximately 2,8 times as much herbicide was found in runoff at Lewiston during 1970 than was present in runoff at Rocky Mount. The rainfall patterns for the two locations were similar in 1969, whereas during 1970 rains during the sampling period were much less frequent at the Rocky Mount site than at the Lewiston site (Appendix Tables 1, 2, 3, and 4). Also, the amount of rainfall during the first 2 months after application at Rocky Mount, when movement in surface water was greatest, was much less than at the other location. - 33 - Table 11. Concentrations of DDT, methyl parathion, toxaphene, and trifluralin in sediment from the pond at Rocky Mount before and after the 1969 and 1970 applications.

Sampl ing Position DDT M. Po Tox . Trifluralin date in pond ( PPm) ( PP~ ( PP~ (PP~

North East South

North eo. 10 East 2.79 South 0.9'1

North East South

North East South

North East South

North East South

North East South

North

North Eqst South Table 12. Concentrations of methyl parathion, toxaphene, and triflu- ralin in water from wells located in cotton fields sprayed with the three pesticides during the 1970 season (Rocky Mount site).

Samp 1 i ng We1 1 deptha M. P. Tox, Trifluralin date (ft) (PP~) (PP~) (PP~) Table 12. Continued

Sampl i ng Wel l deptha bl. P. ?ox . Trifluralin date (ft> (PP~) ( PP~) ( PP~)

a Values are not shown for 4 and 6-ft wells on dates when the water volume was insufficient for sampling.

About 2.5 to 3 times as much DDT was found in surface runoff from plots sprayed with DDT alone as was present in runoff from plots sprayed with DDT plus toxaphene when the same amount of DDT was applied to both plots. It is reasonable to suspect that part of this difference was due to the difficulty of accurately estimating peak areas for the DDT derivatives on the gas chromatographic traces representing samples containing both insecticides (Gaul 1966). However, the magnitude of these differences (reduction of DDT greater than total toxaphene recovered) suggests real values. The oily toxaphene formulation might have acted as a sticker for DDT so that far less was washed from cotton plants when the two insecticides were applied in combination.

Since a high percentage of the DDT removed in runoff was associated with sediment (96x1, movement of DDT into water courses probably could be reduced drastically if functional sediment traps could be devised and installed below watershed areas receiving insecticide applications,

Concentrations in runoff appeared to be related more to intensity of rain than to time after application. Alth~ughthe Table 13. Concentrations of methyl parath!on, toxaphene, and tsiflu- ralin in water from wells located in cotton fields sprayed with the three pesticides during the 1970 season (Lewiston s i te) ,

Samp 1 i ng Well deptha MeP, %ox. Trifluraliw date (ft) (PP~) (PP~) bpb) Table 13. Continued

Samp 1 i ng Wel l deptha M. P. Tox . Trifluralin date (f t) (Wb) bpb) ( PP~)

a Values are not shown for 4 and 6-ft wells on dates when the water volume was insufficient for sampling.

amount of sediment in runoff was not determined, the intensity effect was probably related to the amount of sediment moved. Such a relation may not hold for pesticides that are degraded rapidly in plants and soi 1s.

More toxaphene was present in runoff from combination plots than from toxaphene alone plots; the difference was significant for Lewiston but not for Rocky Mount. There is no obvious explanation for this trend; however, part of the difference might be attributed to our inability to distinguish DDP and toxaphene analytically as discussed above. Also, the presence of additional solvents in the combination have altered the persistence of toxaphene on the foliage.

The amounts of toxaphene in runoff in 1970 were much less than 1969. Direct comparisons of toxaphene data between years are valid only for toxaphene alone treatments because different insecticide formulations in the combination sprays may have affected toxaphene loss in runoff. The apparent difference in toxaphene loss in runoff between years for toxaphene alone treatments can be attributed largely to differences in the amount and frequency of rain. Rains were more frequent in 1969 than in 1970, and total rainfall in 1969 was approximately twice as great as in 1970 (Appendix Tables 7, 8, 13, and 141,

The amount of methyl parathion recovered in surface runoff was much lower than that for either of the other three pesticides, Phis difference is related to the rapid breakdown of methyl parathion on cotton foliage (~radley--et ale 1971).

Trifluralin persisted in higher concentrations in the soil at Lewiston than at Rocky Mount (Table 4), The difference appeared to be related to soil texture and organic matter levels, !n the Rocky ~ountsoil, concentrations of trifluralin declined with time theough- out the sampling periods; at 10 to 11 months after the first and second applications, concentrations were 0,lO to 0.13 ppm, respectively. In contrast, at Lewiston, an initial drop occurred within 2 months after application; and there was little or no loss during the next 8 to 9 months, The pattern of disappearance at Rocky Mount was similar to that reported by Parka and Tepe (19691, whereas that for Lewiston was dissimilar. Our results, especially for the Lewiston location, agree more closely with those of Messersmith --et al. (1971).

Less DBT was recovered from soil taken from plots where DDT was applied in combination with toxaphene than in those where DDT was applied alone. These data are consistent with those for surface runoff and suggest indirectly that more DDT remained on the cotton foliage in the presence of toxaphene khan in its absence, If DDT is retained longer on the leaves, processes such as photodecomposition and volatilization may reduce the total residue on the plot.

During the two spray seasons a total of 48 Ib/A of toxaphene was applied to each toxaphene plote Only on two sampling dates during the study did the residue of toxaphene in the soil exceed the single application of 2 lb/A (Tables 6 and 7)" Residues were 3,2 and 2,6 Ib/A, respectively, in samples collected September 23, 1969 and August 25, 1970 at Rocky Mount. Residues of DDY in soil were greaxer than those for toxaphene (Tables 5 and 69. In addition, more DQT than tsxaphene was removed in surface runoff, Neither DDY nor toxaphene should leach downward in the soil in appreciable quantities. Therefore, we conclude that toxaphene is less persistent than DDP in the cotton field ecosystem.

The only residues of methyl parathion in soil that exceeded the lowest detectable limit of 0,10 ppm were those for the methyl parathion alone treatments sampled during and immediately after the spray season (Tab 1 e 8). These data suggested i ndi rect l y that in the presence sf toxaphene methyl parathion was retained longer on the foliage than in its absence. Results sf experiments co~ductedby the authors during 1971 demonstrated conclusively that toxaphene increased the persistence of methyl parathion on cotton foliage (Bradley et al, 1971).

On a percentage basis, trifluralin appeared to be more persistent than DDT, toxaphene, or methyl parathion in soil, Persistence of trlfluralin Is increased by incorporation in the soil (Savage and Barrentine 1969). in these experiments trifluralln was applied to the soil and incorporated 4 inches, whereas the three insecticides were applied to the foliage. Thus, decsmposltisn of the insecticides probably occurred on or in the plant resulting in a low percentage of the residue in the soi 1,

TrIfluralin was present in low concentrations in pond water (rarely in sediment) on several sampling dates after application In 1969 and 1970 (Tables 9 and 10). The highest concentration of trifluralin (1,6l ppb) found in pond water over the 2-year period was less than the 96-hi- median tolerance limit of 58 ppb for bluegill (Parka and Worth 1965)" From their research Parka and Worth concluded that it was not possible to move enough trifluralin into pond water to kill bluegill when the herbicide was applied at recommended rates.

In 1969 levels of toxaphene in pond water equaled or exceeded the 96-hr median tolerance limit for bluegill of 3,5 ppb (~enderson --et al. 1959) on all but one sampling date after application; - 40 - whereas, levels of DBT did not exceed the 96-hs median tolerance limit (21 ppb for bluegi ll) during the study able 9).

in 1970, residues o,f toxaphene In pond water did not exceed the 96-hr median tolerance limit for bluegilii (~endersonet al. 1959) (Table 10)" The lower concentrations of toxaphene in pond water in 1970, compared to 1969, is attributable to less rainfall in 1970 and to the decrease in area of the watershed treated with toxaphene in 1970.

The highest concentration of methyl parathion found in pond water was 3,5 ppb or about 1/700 of the 96-hr median tolerance limit for bluegi 11 of 2,400 ppb (pickering et ale 19621,

In 1969 there was about four times as much toxaphene as DDT used in the watershed, However, total toxaphene content of runoff from small plots was about equal to or less than the DDT content, although toxaphene was applied at twice the rate for DDT, Data for residues in runoff showed that a high percentage of the DDT (96%) was associated with the sediment, whereas much less toxaphene (75%) was in the sediment fraction, This difference in association with sediment appears Lo be of sufficient magnitude to account for the difference in levels of DDT (maximum about 13 ppb) and toxaphene (maximum about 65 ppb) in pond water, if a major portion of the sediment settled by the time water samples were col lected from the pond.

Toxaphene was much less persistent in soil than DDT. Residues of toxaphene in runoff and in soil from the plots were about equal to or less than those of DDT, even though twice as much toxaphene was applied, However, toxaphene poses a serious acute hazard to aquatic fauna in farm ponds, as evidenced by the high levels found in pond-water samples. Also, the magnitude of toxaphene used for insect control in some watersheds, both the number and frequency of applications and the percentage of watersheds treated, increases the probability for acute toxicity problems. Many dead fish were observed in the pond at Rocky Mount on July 8, 1969. Three intense rain storms occurred during the 4-day period of July 4 to July 8 (Appendix Table 1). A DDT plus toxaphene combination was applied on July 3 to a cotton field within the watershed but outside the experimental area. Water taken from the pond on July 8 contained 7,25 ppb of toxaphene a able 9). On August 6, 1969, the water sample from the pond contained 65 ppb of toxaphene, The area of the pond was about 0.5 acre, and the sprayed portion of the watershed was about 6 acres. DDT plus toxaphene had been applied to the experimental fields several times by August 6,

The data for 1969 can be used to calculate hypothetically the level of contamination of a body of water in a drainage basin, For example, assume a watershed with 10 acres of cotton and a 1-acre pond with an average depth of 4 feet. If 0.5% of a 2 lb/A application of a pesticide (toxaphene) to the 10 acres reached the pond and was contained and equally distributed in the pond, the concentration would be 9 ppb, This concentration exceeds that required to kill some aquatic organ i sms (Henderson et a l 1959).

LI TEMTURE C l TED

1, Alexander, M. 1965. Persistence and biological reactions of pesticides in soils. Soil Sci. Soc. Amer. Proc. 29~1-7,

2, Bai ley, G. W., and J. Lo White. 1965. Review of adsorption and desorptlon of organic pesticides by soil colloids with implications concerning pesticide bioactivity. J. Ag r, Food Chem. 12:324-332,

3. Bailey, G. W. 1966. Entry of biocides into water courses. Broc, Symp, Agr. Waste Waters, Univ. of Calif ., Davis. Report No, 10. (Apr i l 6-8).

4. Barnett, A. P., E. W. Hauser, A. W. White, and J. H. Hol laday. 1967. Loss of 2,4-D in washoff from cultivated fa1 low land. Weeds 15: 133- 137. 5, Bradley, J. R., JreST. J. Sheets, and M, D. Jackson, 1971, North Carolina State University Agricultural Experiment Station, unpubl i shed data.

6. Cope, 0. 6. 1965. Agricultural chemicals and fresh-water ecological systems. p. 115-127, -In C, 0. Chlchester (ed,), Research in pesticides. Academic Press, New York.

7. Edwards, C. A. 1964. Factors affecting the persjstence of insecticides in soil. Soils Fert. 27:451-454.

8, Epstein, E,, and W, J, Grant. 1968. Chlorinated insecticides in runoff water as affected by crop rotation. Soil ScE. Soc. Amer. Proc. 32~423-426,

9. Gaul, Jean A. 1966. Quanti ta tlve calculation of gas chromatographic peaks in pesticide residue analyses. J. Assoc. Offlc. Anal, Chem, 49: 389-399.

10. Henderson, C., and Q. H, Pickering, 1957. Toxicity of organic phosphorus insecticides to fish. Trans. Amer. Fish. Soc. 87233-51.

11. Henderson, C., Q, H. Pickering, and C. M. Tarzwell. 1959. Relative toxicity of ten chlorinated hydrocarbon insecticides to four species of fish. Trans. Amer. Fish. Soc. 88~23-32.

12, Kunze, G, W, 1966. Pesticides and clay minerals. p. 49-70. -In Me E, Bloodworth (ed.), Pesticides and their effects on soi 1s and water. ASA Special Publication No. 8, Soil Sci. Soc. Amer., Onc., Madison, Wi s.

13, Legrand, H. E. 1966, Movement of pesticides in the soil. p. 71-77, -In M. E. Bloodworth (ed.), Pesticides and their effects on soils and water. ASA Special Publ, No, 8, Soil Sci. Soc. Amer., Inc., Madison, Wi s.

14. bichtenstein, E, P,, K, R. Schultz, R. F. Skrenkny, and Y. Tsukane. 1966. Toxicity and fate of insecticide residue in water. Arch. Environ. Health 12:199-212. - 43 - 15. Messersmi th, C. G,, 0, 6. Burnsi de, and T. L. havy. 1971. Biological and non-biological dissipation of trifluralin from soi 1, Weed Sc i , 19:285-290,

16. Newsom, L, D, 1967. Consequences of insecticide use on non- target organ i sms. Annu, Rev. Entomol , 12~257-286.

17. Nicholson, H. P. 1969. Occurrence and significqnce of pesticide residues in water. J. Wash. Acad. Sci. 59~77-85.

18. Parka, S, J., and J. B. Tepe. 1969. The disappearance of trifluralin from field soils. Weed Sci. 17:119-122.

19. Parka, S. J., and H. M. Worth. 1965, The effects of triflural in to fish, Proc. S. Weed Conf, 18~469-473.

20, Pickering, Q, H., C. Henderson, and A. E, Lenke, 1962, The toxicity of organic phosphorus insecticides to different species of warm water fishes. Trans. Amer. Fish, Soc. 91: 175-184.

21. Savage, K. E., andV. L. Barrentine. 1969. Trifluralin persis- tence as affected by depth of soil incorporation. Weed Sci. 17: 349-7352.

22. Sheets, T. J., M. D, Jackson, and L. D. Bhelps. 1970. A water monitoring system for pesticides in North Carolina. Report No, 19, Water Resources Research Institute, Univ. of North Carolina at Raleigh, 105 p.

23. Trichell, D. W., H. L. Morton, and M. G, Merkle. 1968, Loss of herbicides in runoff water. Weed Sci. 16~447-449.

24. US Department of Health, Education, and Welfare. Report of the secretary's commjssion on pesticides and their relationship to envi ronmental health. Parts 1 and I 1, Washington, D. C., 1969. 677 Po 25. Wheatly, G. A. 1965. The persistence, accumulation, and behavior of organochlorine insecticides in soil, Int. Congr. Entomol. Proc. 12~556-557.

26. White, A. W., A. P. Barnett, 6. G. Wright, and J. H. Holladay. 1967. Atrazine losses from fallow land caused by runoff and erosion, Environ. Sci . Technol. 1 :740-744.

PUBbl CAT I ON

Bradley, J, R., Jr., T, J. Sheets, and M. D. Jackson. 197.2, DDT and toxaphene movement in surface water from cotton plots. J. Environ. Quality 1~102-105.

GLOSSARY OF TERMS, ABBREVIATIONS, AND SYMBOLS coefficient af variation C V cubic centimeter (s) cc cent imeter (s) cm 2,4-D (2,4-di ch 1arophenoxy)acet i c ac i d p, p' -DDD 1,l-dichloro-2,2-bis(g-chloropheny1)ethane p, p' -DDE I, 1-dichloro-2,2-bis (g-chlorophenyl)ethylene

0, p-DOT 1,l, 1 -tr i ch loro-2- (0-ch lorophenyl)-2- (pch lorophenyl) ethane 1, 1 , 1-tr ichloro-2,2-bi s (pchloropheny 1) ethane degrees cent l grade C d i camba 3,6-dichloro-o-anisic- acid fluameturon 1,l-dimethyl-3-(a,a,a-trif luoro-m-toly1)urea- feet, foot ft gal lon(s) ga 1 gram(s) g inside diameter i ,d, least significant difference LSD less than < median tolerance limit T Lm methyl parathion (M. P.) -0,O-dimethyl - -0-e-nitrophenyl phosphorothioate mi l l igram(s) mg milliliter(s) m l minute parts per billion parts per mi 1 l ion PPm percent % picloram 4-amino-3,5,6-trichloropicolinic acid pounds per acre 2,4,5-Y (2,4,5-trich1orophenyl)acetic acid toxaphene (tox.) chlorinated camphene containing 67-69% chlorine trifluralin vo 1 ume APPEND l X Appendix Table 1. Rainfall, runoff volume, and amount of trifluralin in runoff during a 5-month period after application of 1 lb/A at Rocky Mount in 1969.

Runoff Trifluralin Trifluralin Samp 1 i ng Ra i nfa l la vo 1 ume concn weight date (4 (1 i ters) (PP~) (W>

a Records for rains which did not cause sufficient runoff for sampling are not shown. Appendix Table 2. Rainfall, runoff volume, and amount of trifluralin in runoff during a 7-month period after application of 1 lb/A at Lewiston in 1969.

Runoff Trifluralin Trifluralin Samp 1 i ng ~ainfalla vo 1 ume concn weight date (cm) (Ii ters) (PP~) h>

a Records for rains which did not cause sufficient runoff for sampling are not shown. Appendix Table 3, Rainfall, runoff volume, and amount of trifluralin in run~ffduring an 8-month period after application of 1 lb/A at Rocky Mount in 1970.

Runoff Trifluralin Trifluralin Sampl ing ~ainfalla vo l ume concn weight date (4 (1 i ters) [PP~) bd

a Records for rains which did not cause sufficient runoff for sampling are not shown. b~nundetermined amount of runoff from rains occurring on July 21-24 was included in this sample. Total rainfall for July 21-30 was 6.38 cm.

C An undetermined amount of runoff from a rain occurring on August 1 (1.32 cm) was included in this sample. Appendix Table 4. Rainfall, runoff volume, and amount of trifluralin in runoff during a 6-m~nthperiod after application of 1 lb/A at bewiston in 1970.

Runoff Trifluralin Trifluralin Samp 1 i ng Rainfal la vo 1 ume concn weight date (cm) (1 iters) (PP~) (md

a Records for rains which did not cause sufficient runoff for sampling are not shown. b~nundetermined portion of the rain recorded for July 23 (3.86 cm) occurred after sampling on that date and was included in the July 24 sampling. Appendix Table 5. Rainfall, runoff volume, and amount of DDP in run- off (DDT applied alone) during a 3-month period at Rocky Mount after initiatiog of the seasonal spray program for insect control.

Runoff b Sampl i ng Rainfall vo 1 ume date (cm> (1 i ters)

a DDT was applied at 1 lb/A on 7-11; 7-15, 7-21, 8-7, 8-12, 8-18, 8-22, 8-27, 9-1, 9-5, 9-8, and 9-12. b~ecordsfor rains which did not cause sufficient runoff for sampling are not shown. Appendix Table 6. Rainfall, runoff volume, and amount of DDT in run- off (DDT applied alone) during a 6-month period at Lewiston after initiation of the seasonal spray a program for insect control.

- Runoff DDT DDT b Sampl l ng Rainfall vo 1 ume concn wef ght date (cm> (1 i ters) (PP~) (md

a~~~ was applied at 1 Ib/A on 7-1 1, 7-15, 7-21, 8-7, 8-12, 8-18, 8-22, 8-27, 9-1, 9-5, 9-8, and 9-12. b~ecordsfor rains which did not cause sufficient runoff for sarnpl i ng are not shown. Appendix Table 7. Rainfall, runoff volume, and amount of toxaphene in runoff (toxaphene appl led a lone) during a 3-month period at Rocky Mount after initiation of &he seasonal spray program for insect control,

Runoff Tox , %ox. b Sampl ing Rainfall vo l ume concn weighr date d 4 (1 i ters) (PP~) hd

a Poxaphene was applied at 2 lb/A on 7-11, 7-15, 7-21, 8-7, 8-12, 8-18? 8-22, 8-27, 9-1, 9-5, 9-8, and 9-12.

b~ecordsfar rains which did not cause sufficient runoff for sampl ing are not shown. Appendix Table 8, Rainfall, runoff volume, and amount of toxaphene in runoff (toxaphene appl ied alone) during a 6-month period at Lewiston after initiation of the seasonal a spray program for insect control.

Runoff Tox Tox b . . Samp l i ng Rainfall vo 1 ume concn weight date (4 (1 i ters) (PP~) (W>

a Toxaphene was applied at 2 lh/A on 7-11, 7-15, 7-21, 8-7, 8-12, 8-18, 8-22, 8-27, 9-1, 9-5, 9-8, and 9-12. b~ecordsfor rains which did not cause sufficient runoff for sampl ing are not shown. Appendix Table 9. Rainfall, runoff volume, and amounts of DDT and toxaphene i n runoff (DDT and toxaphene app 1 i ed i n combination) during a 3-month period at Rocky Mount after initiation of the seasonal spray program for a insect control.

Runoff Concentrations of Weights of Saml i nu Rainfall volume DDT Tox. DDT Tox.

a DDT and toxaphene were applied at 1 + 2 Ib/A on 7-11, 7-15, 7-21 , 8-3, 8-12, 8-18, 8-22, 8-27, 9-1, 9-5, 9-8, and 9-12. b~ecordsfor rains which did not cause sufficient runoff for samp 1 ing are not shown. Appendix Table 10, Rainfall, runoff volume, and amounts of DDT and toxaphene in runoff (DDT and toxaphene appl led in combination) during a 6-month period at Lewiston after initiatio; of the seasonal spray program for insect control.

Runoff Concentrations of Weights of b Sampling Rainfall vo 1 ume DDT Tox. DDT Tox , date (cm> (1 i ters) (PP~) (PP~) b9> (md

a DDT and toxaphene were applied at 1 + 2 lb/A on 7-11, 7-15, 7-21$ 8-7, 8-12, 8-18, 8-22, 8-27, 9-1, 9-5, 9-8, and 9-12. b~ecordsfor rains which did not cause sufficient runoff for sampling are not shown. Appendix Table 11. Rainfall, runoff volume, and amount of methyl parathion in runoff (methyl parathion applied aione) during a 6-month period at Rocky Mount after initiation of the seasonal spray program a for insect control.

Runoff M. P, M. P. b Samp 1 i ng Rainfall vo l ume concn weight date (cd ( I l ter s) ( PP~) (md

a Methyl parathion was applied at 1 lb/A on 7-13, 7-18, 7-24, 7-30, 8-6, 8-il, 8-18, 8-21, 8-25, 8-31, 9-5, and 9-10. b~ecordsfor rains which did not cause sufficient runoff for sampling are not shown. c An undetermined amount of runoff from rains occurring on July 21-24 was included in this sample, Total rainfall for July 21-30 was 6.38. d~nundetermined amount of runoff from a rain occurring on August 1 (1.32 cm) was included in this sample. Appendix Table 12. Rainfall, runoff volume, and amount of methyl parathion in runoff (methyl parathion applied alone) during a 4-month period at Lewiston after initiation of t$e seasonal spray program for insect control.

Runoff M. P. M. P. b Samp 1 i ng Rainfall volume concn weight date (cm) (1 i ters) (PP~) (W)

a Methyl parathion was applied at 1 lb/A on 7-13, 7-18, 7-24, 7-30, 8-6, 8-11, 8-18, 8-21, 8-25, 8-31, 9-5, and 9-10. b~ecordsfor rains which did not cause sufficient runoff for sampling are not shown.

C An undetermined portion of the rain recorded for July 23 (3.86 cm) occurred after sampling on that date and was included in the July 24 sampl i ng. Appendix Table 13. Rainfall, runoff volume, and amount of toxaphene in runoff (toxaphene applied alone) during a 6- month period at Rocky Mount after initiation o$ the seasonal spray program for insect control.

Runoff Tox Tox b . . Sampl l ng Rafnfal 1 vs 1 ume concn weight date (4 (1 i tess) (PP~) h9>

a. roxaphene was applied at 2 Ib/A on 7-13> 7-18, 7-24, 7-30, 8-6, 8-11, 8-18, 8-21, 8-25, 8-31, 9-5, and 9-10. b~ecordsfor rains which did not cause sufficient runoff for sarnpl ing are not shown.

C An undetermined amount of runoff from rains occurring July 21-24 was included in this sample. Total rainfall for July 21-30 was 6.38 cm, d~nundetermined amount of rainfal l from a rain occurring on August I (1,32 cm) was included in this sample, Appendix Table 14. Rainfal 1, runoff volume, and amount of toxaphene in runoff (toxaphene applied alone) during a 4- month period at Lewiston after initiation gf the seasonal spray program for insect control,

Runoff Tox. Tox , b Samp l i ng Rainfall vo 1 ume concn weight date (cm) (1 i ters) (PP~) bd

a Toxaphene was applied at 2 lb/A on 7-13, 7-18, 7-24, 7-30, 8-6, 8-11, 8-18, 8-21, 8-25, 8-31, 9-5, and 9-10. b~eccrdsfor rains which di d not cause sufficient runoff for sampl ing are not shown.

C An undetermined portion of the rain recorded for July 23 (3.86 cm) occurred after sampling on that date and was included in the July 24 sampl ing. Appendix Table 15. Rainfal 1, runoff voiume, and amounts of methyl ' parathion and toxaphene in runoff (methyl parathion and toxaphene appl ied in combination) during a 6- month period at Rocky Mount after initiation of the a seasonal spray program for insect control.

Runoff Concentrations of Weights of b Sampling Rainfall vo 1 ume kz, Po Tox, M, Po Tox . date (cd (1 i ters) (PP~) bpb) h> (Gl>

a Methyl parathion and toxaphene were applied at 1 =+ 2 Ib/A on 7-13, 7-18, 7-24, 7-30, 8-6, 8-1 I, 8-18, 8-21, 8-25, 8-31, 9-5, and 9-10, b~ecordsfor rains which did not cause sufficient runoff for sarnpl ing are not shown.

C An undetermined amount of runoff from rains occurring on July 21-24 2 was included In this sample. Total rainfall for July 21-30 was 6.38 cm. dAn undetermined amount of runoff from a rain occurring on August 1 (1.32 cm) was included in this sample. Appendix Table 16. Rainfall, runoff volume, and amounts of methyl parathion and toxaphene in runoff (methyl parathisw and toxaphene applied In combination) during a 4- month period at bewlston after initiation gf the seasonal spray program for insect control.

Runoff Concentrations of Weights ~f b Sampl i ng Rainfall vo 1 ume M. Po Tox. M. P. TOM. date (cm) ( 1 i ters) (PP~) (PP~) h9> &W>

a Methyl parathion and toxaphene were applied at 1 + 2 lb/A on 7-13, 7-18, 7-24, 7-30, 8-6, 8-1 1, 8-18, 8-21, 8-25, 8-31, 9-5, and 9-10. b~ecordsfor rains which did not cause sufficient runoff for sampling are not shown.

C An undetermined portion of the rain recorded for July 23 (3.86 cm) occurred after sampling on that date and was included in the July 24 sampl i ng.