Historic Document – Content May Not Reflect Current Scientific Research, Policies Or Practices

U.S. Department of Agriculture Animal and Plant Health Inspection Service Wildlife Services

Historic document – Content may not reflect current scientific research, policies or practices.

Technical Papers OF THE BUREAU OF SPORT FISHERIES AND WILDLIFE

46. Acute Toxicities of Organochlorine and Organophosphorus Insecticides to Estuarine Fishes

By Ronald Eisler

United States Department of the Interior, Walter J. Hickel, Secretary Leslie L. Glasgew, Assistant Secretary for Fish and Wildlife, Parks, and Marine Reso'urces Fish and Wildlife Service, Charles H. Meacham, Commissioner Bureau of Sport Fisheries and Wildlife, John S. Gottschalk, Director Washington, D.C. March 1970 CONTENTS

Page

Abstract. • • • • • • • • . • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • 3

Methods • • . • . • • . . • • • • • • • • • • • • • . • • . • • • • • • . . • • • • • . 3

Results. . • • . • . . • . • • • • • • • • • • • • • . • . • • • • • . • • • • . . • . • 5

Discussion • • • • • • • • . . • • • • • . . . • • • . • . • • • • • • • • • • • • • . 9

Summary and conclusions • • • • • . • • • • . . • • . • • . . • . . • • • • • • 10

References • • • • • . . • . • . . . • • • . • . • • . • • • • • • • • • • • . • • • . 11

2 ACUTE TOXICITIES OF ORGANOCHLORINE AND ORGANOPHOSPHORUS INSECTICIDES TO ESTAURINE FISHES

By Ronald Eisler

U.S. Bureau of Spon Fisheries and Wildlife Fish-Pesticide Research Program Sandy Hook Marine Laboratory, Highlands, New Jersey

ABSTRACT .--Static 96-hour bioassays with 12 insecticides and seven species of estuarine teleosts (American eel, Anguilla rostrata; mummi chog, Fundulus heteroclitus; striped killifish, Fundulus majalis; bluehead, Thalassoma bifasciatum; striped mullet, Mugil cephalus; Atlantic silver side, Menidia menidia; nonhern puffer, S~oides maculatus) were

conducted at 24\0 salinity, 20° C., and pH 8,0, Endrin was consistently the most toxic and methyl parathion consistently the least toxic compound tested. The descending order of insecticide toxicity to fishes at 96 hours was endrin, p,p'-DDT, dieldrin, aldrin, dioxathion, heptachlor, lindane, methoxychlor,-Phosdrin, malathion, DDVP, and methyl parathion. Concentrations fatal to 50 percent of each species in 96 hours (LC50 values) ranged from 0,05to 3.1 micrograms per liter (ppb) active ingre dients with endrin, 0,4 to 89 ppb with p,p'-DDT, 0.9 to 34 ppb with dieldrin, 6 to 75 ppb with dioxathion, 0,8 to 19rppb with heptachlor, 9 to 66 ppb with lindane, 12 to 150 ppb with methoxychlor, 65 to 800 ppb with Phosdrin, 27 to 3,250 ppb with malathion, 225 to 2,680 ppb with DDVP, and 5,200 to 75,800 ppb with methyl parathion.

Numerous problems are associated with the teleosts. It is one of a continuing series of widespread use and occurrence of synthetic repons (Eisler and Edmunds, 1966; Eisler insecticides in aquatic habitats (Cope, 1965; and Weinstein, 1967; Eisler, 1967, 1969a, Tarzwell, 1965), Marine and brackish-water l 969b) documenting effects of pesticides on species that frequent coastal inshore environ marine and estuarine organisms. ments are panicularly susceptible to chemical I am obligated to William Birkhead, Philip insecticides because of the propensity of these Edmunds, George Gardner, Louise Geller, compounds to diffuse from drainage systems Louis Ortiz, William Reisen, Ann Sawyer, and accumulate in estuaries (Butler, 1966; Melvin Weinstein, and Wayne Weseman for Eisler, 1968), This account repons on the their aid in procurement of test animals and toxicity of 12 common insecticides during a maintenance of experiments. 96-hour period to seven species of estuarine METHODS The author's present address is U.S. Depanment of the Interior, Federal Water All experiments were conducted at the Sandy Pollution Control Administration, National Hook Marine Laboratory, Highlands, N, J, Marine Water Quality Laboratory, West in a windowless room at 20° ± 0,5° C, Illu Kingston, Rhode Island 02892. mination consisted of 20 to 25 foot-candles

3 4 Technical Paper 46: Bureau of Sport Fisheries and Wildlife

for about 10 hours daily alternating with 2 to individual assay aquariums to achieve desired 3 ft.-c. for about 14 hours, delivered by fluo concentrations. Experimental aquariums were rescent and incandescent sources. Seawater of 20-liter jars filled with 19 liters of test 24°fc, 0 ± i% 0 salinity and pH 8,0 ± 0.1 was medium. Each jar was covered with a glass obtained from a well 19 meters underground. disk perforated with a single hole 6 mm in A major advantage of the ground water supply diameter. Results of preliminary tests at is the elimination of detritus, plankton, and Sandy Hook showed that many species of attaching organisms, any of which if present marine fishes died within 24 hours unless the in sufficient abundance would probably affect static medium was aerated; accordingly, fil results of toxicity experiments. Additional tered compressed air was supplied via 3-mm information on composition of the test medium glass tubing. Aeration did not measurably is documented by Clark and Eisler (1964). affect pH, salinity, or temperature of the test medium. Dissolved oxygen content of media among the test jars was determined periodi Seven organochloride and five organophos cally with a YSI oxygen probe, and ranged phorus insecticides were tested. All com between 7.1 and 7.7 mg per liter. To insure pounds, with the exception of DDVP, were complete mixing, insecticides were added procured from the Entomological Society to the aerated test medium 45 minutes be of America (Dawsey, 1964). ESA reference fore the assay species. Results of repeated standards were p,p'-DDT (l,l,l-trichloro-2, 96-hour bioassays that I conducted indicate 2-bis(p-chlorophenyl)ethane); aldrin (1,2,3, negligible loss in toxicity of any test insecti 4, 10, 10-hexachloro-l,4,4a,5, 8,8a-hexahydro-l, cide during the first 45 minutes. 4-endo__ ,_ exo-5 . 8-dimethanonaphthalene); dieldrin (1,2,3,4,10,10-hexachloro-6, 7-epoxy-l, Between April 1964 and June 1966, seven 4,4a,5,6, 7,8,8a-octahydro-l,4-endo,exo-5, species of estuarine teleosts were collected 8-dimethanonaphthalene); endrin (1,2,3,4,10, and tested: American eel, Anguilla rostrata 10-hexachloro-6, 7-epoxy-l,4,4a,5,6, 7,8, (Lesueur), Anguillidae; mummichog, Fundulus Ba-octahydro-l,4-endo,endo-5,8-dimethano- heteroclitus (Linnaeus), Cyprinodontidae; n a p ht ha 1 en e); heptachlor (1,4,5,6, 7,8, striped killifish, Fundulus majalis (Wal 8-heptachloro-3a,4,7, 7a-tetrahydro-4, 7-endo baum), Cyprinodontidae; bluehead, Thalassoma methanoindene); lindane ( 1, 2, 3, 4, 5, 6-hexa bifasciatum (Bloch), Labridae; striped mullet, chlorocyclohexane, gamma isomer); methoxy Mugil cephalus Linnaeus, Mugilidae; Atlan chlor (2, 2-bis(p-m et ho x y p hen y 1)-1, 1, tic silverside Menidia menidia (Linnaeus), I-trichloroethane), malathion (Q,Q-dimethyl Atherinidae; and northern puffer, Sphaeroides .§-[1,2-di(ethoxycarbonyl)ethyl]phosphorodi maculatus (Bloch and Schneider), Tetraodon thioate); methyl parathion (Q,Q-dimethyl tidae. All species except eels, blueheads, and 0-P-nitrophenyl phosphorothioate); Phosdrin puffers were collected with a beach seine dimethyl <2-~arboxymethoxy-l-propen-2-yl from Sandy Hook Bay. Puffers were taken phosphate and its beta isomer); and dioxathion from a commercial fish trap in Sandy Hook (2,3-p-dioxane ~.~-bis(Q,Q-diethylphosphoro Bay. Eels were seined from the outlet of dithioate). A sample of DDVP

2 The range in LC25 (96h) and LC75 (96h) values n(n - 1) was from 0,03 ppb minimum for endrin to 104,000 ppb maximum for methyl parathion (table "'6ere rs = rank correlation coefficient (with 9). With minor exceptions, all LC25 (96h) values distribution identical to that of the correlation were within 15 to 64 percent of their respective coefficient, r, when n is equal to or greater LC50 (96h) values; for LC75 (96h) values, com · than 8) parable ratios were 150 to 300 percent.

n = number of ranks (here 12) Endrin was consistently the most toxic d =differences between any two rankings compound and methyl parathion the least 6 Technical Paper 46: Bureau of Sport Fisheries and Wildlife

TABLE 1.--Acute toxicity of 12 insecticides to the Atlantic silverside [Minimum of five test concentrations used, lO fish per concentration] LC5a in micrograms Total Mean Mean Total weight per liter (ppb) active Insecticide number length weight ingredients at-- fish (mm) per jar (g) (g) 24h 48h 96h arga,nochlorine: endrin. ••••••••• •••••••• , 5a 54 a.9 9 a.5 a .as a.a5 _E,_E 1 -DDT • • • • •••••••••• ·••• 5a 59 1.2 12 4 a.4 a .4 heptachlor ••••••••••• •••• 60 54 a . 9 9 24 6 3 dielclrin. •• • ••••••••••••• 5a 57 2.a 2a lO 5 5 lindane •••••••••••••• •• , • 5a 57 2.a 20 23 20 9 alclrin••• •••••••••••••••• 5a 57 2.a 2a 45 20 13 methoxychlor •• • ••• • •••••• 5a 57 2.a 2a 44 44 33 arganophosphorus: dioxathion• ••••••••• •• ••• 60 5a a.a 8 7 7 6 malathion. ••••••••••••••• 60 5a a.8 8 315 315 125 Phosclrin. •••••••••••••• •• 60 5a a.a 8 9aa 47a 320 DDVP ••••• • •••• • ••••• • •••• 5a 5a a.a 8 5,700 3,45a l , 25a methyl parathion •••••• • •• 6a 5a a.a 8 24,800 21,900 5,7aa

TABLE 2.--Acute toxicity of l2 insecticides to the bluehead [Minimum of five test concentrations used, five fish per concentration]

Total 105a in micrograms Total Mean Mean weight per liter (ppb) active Insecticide number length weight ingredients at-- fish (mm) (g) per jar (g) 24h 48h 96h arganochlorine: enclrin•••••••••••••••• • •• 25 9a 7,a 35 a.6 a.5 a.1 heptachlor •••••••••••••• • 25 Sa 5.4 27 17 8 a.8 dieldrin••••••••••• • ••••• 25 sa 5.4 27 7 6 6 ,,E,,,E'-DDT • ••• • • • •••• • ••••• 25 Sa 5.4 27 17 4 7 alclrin •••••• •• •••••••• • •• 25 Sa 5.4 27 l5 l5 l2 methoxychlor ••••••••••••• 25 Sa 5.4 27 14 13 13 lindane •••••••••••••••••• 25 90 7.a 35 14 14 14 arganophosphorus: malathion•••••••••••••••• 25 Sa 5.4 27 33 27 27 dioxathion••••••••••••••• 3a sa 5.4 27 60 43 35 Phosdrin. •••••••••••••••• 3a Sa 5.4 27 592 343 74 DDVP ••••••••••• • ••••••••• 25 Sa 5.4 27 l,75a l,75a l,440 methyl parathion •••• •••• • 25 9a 7.a 35 98,aaa 88,aaa l2,3aa

TABLE 3.--Acute toxicity of 12 insecticides to the striped killifish [Minimum of five concentrations used, eight to la fish per concentration] 105a in micrograms Mean Total Total Mean weight per liter (ppb) active Insecticide number length weight per jar ingredients at-- fish (mm) (g) (g) 24h 48h 96h arganochlorine: endrin••••••••••••••••••• 60 40 a.92 9.2 1.8 a.7 a.3 ,,E,,,E'-DDT ••••••••••••••••• 7a 40 a.92 9.2 3 2 1 dieldrin••••••••••••••••• 5a 40 a.92 9.2 9 7 4 aldrin••••••••••••••••••• 5a 49 1.6 16.a 58 26 17 lindane • • •••••••••• • ••••• 5a 49 1.6 16.a 28 28 28 methoxychlor ••••••••••••• 60 40 a.92 9.2 38 34 3a heptachlor ••••••••• •••• • • 60 40 a.92 9.2 5a 43 32 Organophosphorus: dioxathion••• • •••• • •• •••• 40 84 6.5 26.a l5 l5 l5 Phosclrin. •••••••••••••••• 40 84 6.5 26.a 75 75 75 malathion. •• •••• • •••••••• 4a 84 6.5 26.a 28a 25a 25a DDVP ••••••••••••••••••••• 60 40 a.92 9.2 2,400 2,400 2,3aa methyl parathion••••••••• 48 84 6.5 26.a 29,ooa 19,400 l3,8aa Ronald Eisler: Toxicities of Insecticides to Estuarine Fishes 7

TAI!LE 4.--Acute toxicity of 12 insecticides to the striped llllllet [Minimum of five test concentrations used, six to lD fish per concentration)

Total LC50 in micrograms Total Mean Mean weight per liter (ppb) active Insecticide Illll!lber length weight ingredients at-- fish (mm) (g) per jar ( g) 24h 48h 96h Organochlorine: endrin••••••••••.••••••• • 40 83 6.9 27.6 0.7 0.3 0.3 .EJ.12'-DDT ••••••••••••••••• 60 46 1.0 lD,O 4 0. 9 0.9 1 J21 J2 -DDT ...... 56 88 6.8 27.2 7 6 3 dieldrin. •••••••••••••••• 50 85 6.6 33.0 25 25 23 metho:xychlor •••••••••.•.• 45 lDO 12.6 37.8 63 63 63 lindane •••••••••••••.••. • 50 85 6.6 33.0 75 71 66 aldrin...... 60 85 6.6 33.0 126 100 100 hej>tachlor ••••••••••••••• 54 100 12.6 37.8 224 208 194 Organophosphorus: dioxathion. •••••••••••••• 60 85 6.6 33.0 90 64 39 DDVP ••••••••••••••••••••• 50 84 6.4 32.0 735 660 200 DDVP ••••••••••••••••••• • • 35 46 1.0 7.0 1,750 1,250 250 Phosdrin••••••••••••••••• 36 lDO 12.6 37.8 300 300 300 malathion. ••••••••••••••• 42 48 0.78 5.5 > ~60 550 550 methyl parathion••••••••• 49 48 0.78 5.5 39,000 26,300 5,200

TABLE 5. --Acute toxicity of 12 insecticides to the American eel [ Minilnwn of six test concentrations used, lD eels per concentration) LC50 in micrograms Total Total Mean Mean weight per liter (ppb) active Insecticide munber length ingredients at-- weight per jar fish (mm) (g) (g) 24h 48h 96h

Organochlorine: endrin ••••••••••••••.•••• 70 57 0.16 1.6 1.1 0.6 0.6 dieldrin••••••.•••••••••. 70 57 0.16 1.6 8 4 0.9 J2,J2 1 -DDT ...... 190 56 0.18 1.8 7 6 4 aldrin•••••• • •••.•••••••• 90 56 0.18 1.8 18 5 5 heptachlor •.••.•••••••••• 90 56 0.18 1.8 71 49 10 metho:xychlor ••••••.•••••. 70 56 0.18 1.8 25 25 12 lindane •••••••••••..••.•. 70 56 0.18 1.8 70 70 56 Organophosphorus: dioxathion. ••• • ••••••.• • • 60 59 o. M 1.4 7 6 6 Phosdrin•••••••.••••••••• 60 59 O. JA. 1.4 84 84 65 malathion•••••••••••••••• 60 57 0.16 1.6 82 82 82 DDVP ••••••••••••••••••••• 60 59 o. JA. 1.4 2,300 2,300 1,800 methyl parathion••••••••• 90 59 o. JA. 1.4 27,600 22,400 16,900

TABLE 6.--Acute toxicity of, 12 insecticides to the mummichog [Minimum of five test concentrations used, seven to lD fish per concentration) LC50 in micrograms Total Mean Mean per liter (ppb} active Total weight ingredients at-- Insecticide number length weight per jar fish (mm) (g} ( g) 24h 48h 96h

Organochlorine: endrin•••••••••••••••••• • 49 51 1.8 12.6 1.8 0.7 0.6 1.5 endrin.• • ••••••••••• • • •• • 50 55 1.4 JA..O 5.6 4.2 J2,J2'-DDT ••••••••••••••••• 70 55 2.0 20.0 11 5 5 aldrin•••.••••••••••••••• 80 55 2.0 20.0 22 16 8 dieldrin. •••••••••••••••• 49 51 1.8 12.6 20 9 5 dieldrin...... 60 55 1.7 17.0 30 28 16 metho:xychlor ••••••••••••• 70 55 2.0 20.0 37 35 35 62 57 metho:xychlor ••••• • • • • • • • · 60 55 1.7 17.0 85 heptachlor ••••••••••••••• 70 55 2.0 20.0 83 67 50 lindane •••••••••••••••••• 60 55 2.0 20.0 66 60 60 Organophosphorus: dioxathion. ••••••••••• • •• 60 56 2.5 25.0 23 21 20 malathion. •••••••••••••• • 80 56 2.5 25.0 130 80 80 malathion••••••••••• • •••• 50 55 1.8 18.0 810 440 400 70 56 2.5 25.0 365 300 300 Phosdrin••••••••••••••••• 2,680 DDVP ••••••••• • •• • •••••••• 60 55 1.7 17.0 3,410 2,680 58,000 methyl parathion. •••••••• 70 55 1.7 17.0 >85,200 85,200 8 Technical Paper 46: Bureau of Spon Fisheries and Wildlife

TABLE 7.--Acute toxicity of 12 insecticides to the northern puffer [Minimum of five test concentrations used, six to 10 puffers per concentration] LC50 in micrograms Total Mean Mean Total per liter (ppb) active Insecticide munber length weight weight ingredients at-- fish ( DDll) (g) per jar (g) 24h 48h 96h Organochlorine: endrin••••••••••••••••••• 60 131 46 46 3.1 3.1 3.1 dieldrin. •••••••••••••••• 30 168 100 100 34 34 34 lindane •••••••••••••••••• 30 168 100 100 41 41 35 aldrin••••••••••••••••••• 30 168 100 1 100 44 36 36 ,E1,E -DDT ••••••••••••••••• 70 146 63 63 115 89 89 methoxychlor ••••••••••••• 50 203 199 199 188 160 150 heptachlor ••••••••••••••• 30 168 100 100 240 188 188 Organophosphorus: dioxathion. •••••••••••••• 30 168 100 100 220 96 Phosdrin. •••••••••••••••• 75 30 168 100 100 895 895 800 DDVP ••••••••••••••••••••• 30 168 100 100 2,250 2,250 2,250 malathion. ••••••••••••••• 42 183 126 126 9,000 6,000 3,250 methyl parathion. •••••••• 60 196 153 153 100,000 91,000 75,800

TABLE 8.--Summary of LC50(96h) values of seven organochlorine and five organophosphorus insecticides vs. seven species of estuarine fishes at 24~ 0 salinity, 20° c., and pH 8.0 [Data are from tables 1-7) Atlantic Striped American Northern Insecticide Bluehead MU!mnichog silverside killifish eel puffer

Organochlorine: endrin••••••••••••••••••••••••• 0.05 0.1 0.3 0.6 1.0 3.1 _E,,E 1-DDT ••••••••••••••••••••••• 0.4 7 1 4 5 89 heptachlor ••••••••••••••••••••• 3 0.8 32 10 50 188 dieldrin••••••••••••••••••••••• 5 6 4 0. 9 10.5 34 lindane ••••••••••••••••• • •••••• 9 14 28 56 60 35 aldrin••••••••••••••••••••••••• 13 12 17 5 8 36 methoxychlor ••••••••••••••••••• 33 13 30 12 46 150 Organophosphorus: dioxathion. •••••••••••••••••••• 6 35 15 6 20 75 malathion••••••••••••••• • •••••• 125 27 250 82 240 3,250 Phosdrin••••••••••••••••••••••• 320 74 75 65 300 800 DDVP ••••••••••••••••••••••••••• 1,250 1,440 2,300 1,800 2,680 2,250 methyl parathion. •••••••••••••• 5,700 12,300 13,800 16, 900 58,000 75,800

TABLE 9.--Range in LC25(96h) and LC75(96h) values for 12 insecticides vs seven species of estuarine teleosts [All values are in micrograms per liter (ppb) active ingredients]

LC75 Insecticide Minimum I Maximum

endrin ••••••••••••••••••••••••• 0.03 1.9 0.08 4.5 p,p'-DDT ••••••••••• ,. •••.•••••• 0.2 49 0.8 129 dieldrin ••••••••••••••••••••••• 0.04 17 1.3 110 aldrin ••••••••••••••••••••••••• 2 66 8 150 dioxathion ••••••••••••••••••••• 3 22 8 180 heptachlor •••••.••••••••••••••• 0.4 106 6 328 lindane •••••••••••••••••••••••. 4 45 19 87 methoxychlor ••••••••••••••••••• 6 75 19 225 Phosdrin •••••••••••.••••••••••• 42 550 130 1,045 malathion ••••••••••.•.••••••••• 16 1,750 39 4,750 DDVP ••••••••••••••••••••••••••• 87 2,100 312 4,800 methyl parathion ••••••••••••••• 3,250 50,500 7,100 104,000 Ronald Eisler: Toxicities of Insecticides to Estuarine Fishes 9

TABLE 10.--Rank order in toxicity or 12 insecticides to seven species or marine teleosts [ l = 11Dst toxic to 50 percent in 96 hours; 12 = least toxic]

Atlantic Striped Northern Insecticide Bluehead Striped American Total silverside killifish mullet eel Mummichog pui'rer endrin•.••.•.••.•.•....•...... • l l l l l l 1 7 EJE'-DDT., ...... , 2 4 2 2 3 2 6 21 dieldrin •••••••••••••••.••.•••• 4 3 3 3 4 21 aldrin. ••••••••••••••• • •••••.•• 2 2 7 5 5 7 4 3 4 35 dioxathion. •••••••••••••••••••• 5 9 4 4 5 5 5 37 heptachlor ••••••••••••••••••••• 3 2 8 8 6 7 8 42 lindane •••••••••••••••••••••••• 6 7 6 6 8 8 3 44 methoxychlor ...... 8 6 7 5 7 6 7 46 Phosdrin••••••••••••••••••••••• lD lD 9 lD 9 10 9 67 malathion•••••••••••• , ••••••••• 9 8 lD 11 lD 9 11 68 DDVP ••••••••••••• •••••••• •• • ••• 11 11 11 9 11 11 10 74 methyl parathion. •••••••••••••• 12 12 12 12 12 12 12 84

toxic (table 10), Intermediate in toxicity were LC75 (96h) values for organochlorine insecti p,p'-DDT, dieldrin, aldrin, dioxathion, hepta cides as a function of the LC50 value fell ch1or, lindane, methoxychlor, Phosdrin, mala within limits observed in this study. thion, and DDVP. This sequence of toxicity was in concordance at the 0.01 level for each Variation in resistance to organochlorine of the assay species, as determined by rank insecticides is documented for freshwater correlation. Furthermore, rs values between fishes by Henderson et al. (1960) and Tarzwell any two assay species were also in signifi ( 1963). They found that LC50 (96h) values cant concordance at the 0.01 level (all rs ranged between 0,6 ppb of endrin with sunfish values >+0.661). to 230 ppb of heptachlor with goldfish. Inter species differences in age, size, and biomass/ volume ratio from the present study preclude DISCUSSION any general statement about toxicity of indi vidual organochlorine insecticides; however, LC50 (96h) values from toxicity bioassays the four lowest LC50 (96h) values recorded with organochlorine insecticides and marine in ppb ranged between 0.05 and 0.3, all for fishes in this study are similar to those pre endrin, and the two highest were 188 and 194, sented for various species of freshwater both for heptachlor. teleosts (Henderson et al., 1959; Ludemann and Neumann, 1962; Tarzwell, 1963) and for The organophosphorus insecticides were three species of marine decapod crustaceans toxic to marine teleosts in the range of LC50 (Eisler, 1969a). Moreover, LC50 (96h) values (96h) values from 6 to 75,800 ppb and, with the from marine assays with endrin, p,p'-DDT, possible exception of dioxathion, were less and heptachlor against northern pjpefish, toxic than organochlorine insecticides. Simi Syngnathus fuscus Storer, bluefish, Pomatomus lar findings were obtained by others who saltatrix (Linnaeus), and winter flounder, showed that LC50 (96h) values for organo Pseudopleuronectes americanus (Walbaum), phosphorus insecticides and freshwater tele were within the ranges observed for these osts extended from 5 to 610,000 ppb (Pickering compounds in the present study (Eisler, et al., 1962), and that most organophosphorus unpublished). But estuarine clams, Mercenaria insecticides were less toxic to freshwater mercenaria, and gastropods, Nassa obsoleta, fishes than organochlorine insecticides (Hen under comparable test conditions, were more derson and Pickering, 1958; Ludemann and resistant to all seven organochlorine com Neumann, 1962). pounds by at least several orders of magnitude (Eisler, unpublished). In every case where Results of unpublished toxicity assays that comparison was possible, LC25 (96h) and I conducted at 24% 0 salinity with malathion, 10 Technical Paper 46: Bureau of Sport Fisheries and Wildlife

methyl parathion, and DDVP against north resistance to organophosphorus compounds. ern pipefish, bluefish, sheepshead minnow These factors include species differences in Cyprinodon variegatus Lacepede, and three resistance of cholinesterases and differ spine stickleback Gasterosteus aculeatus ences in rates of enzymatic activation and Linnaeus indicated large interspecies vari inactivation of insecticides. A recent paper by ations in susceptibility. When compared Murphy et al. (1968) on anticholinesterase with toxicity data from this study, LC50 action of phosphorus insecticides concludes (96h) values were lower for bluefish vs mala that for some compounds species differences thion (8 ppb), bluefish vs DDVP (90 ppb), and in the sensitivities of the cholinesterases to sticklebacks vs methyl parathion (1,180 ppb), inhibition are sufficiently large to modify the and higher for sheepshead minnow vs DDVP influence of differences in rates of metabo ( 15,200 ppb) and sheepshead minnow vs methyl lism. In addition, Murphy et al. demonstrated parathion (89,400 ppb); all other values were that species differences in the reactivities of within the range observed in this study. As brain cholinesterases with the oxygen analogs was true with organochlorine insecticides, of some phosphorus insecticides contributed almost all LC25 (96h) values for any organo significantly to species differences in sus phosphorus insecticide and any species fell ceptibility to poisoning. within 15 to 64 percent of their respective LC50 (96h) value; for LC75 (96h) levels, a LC50 (96h) values for assays with marine similar range was 150 to 300 percent. teleosts and insecticides were also affected, to as much as one order of magnitude, by each Interspecies differences in susceptibility to of a number of factors. These include tem organophosphorus insecticides were negligible perature, salinity, and pH of medium, plus among closely related species when compared degradation rate and resultant byproducts of with differences between species from dif test biocides (Eisler, 1969b). For example, ferent phyla. Thus, in resistance to organo studies with mummichogs and various organo phosphorus insecticides, marine teleosts were phosphorus insecticides demonstrated that distinctly intermediate between the highly pesticide-induced mortality increased with susceptible marine decapod crustaceans increases in temperature between 10° and (Eisler, 1969a) and the relatively resist- 30° C., and also with increases in salinity be ant marine mollusks (Eisler, unpublished). tween 12%0 and 36°/00; toxicity was inversely Accordingly, I recommend that future marine proportional to pH in the range 5.5 - 10.0. toxicity assays use species from a minimum The toxicity of organochlorine insecticides to of three taxonomically distinct groups such mummichogs, was greatest at intermediate as the teleosts, the crustaceans, and the (20°- 25° C.) temperatures and lowest at mollusks. Results from those assays would intermediate (7.0- 8.0) pH within the ranges provide a more realistic base line for evalu tested; salinity of the medium had little or no ation of comparative toxicities of biocides and effect on pesticide-caused mortality. In addi comparative sensitivities of species than tion, there was a marked loss in potency of would tests of closely related species. many pesticides to mummichogs, especially aldrin and heptachlor during 96 hours; but, during a similar period, Phosdrin and methyl Generally, both in vertebrates and in inver parathion were about 5 times as toxic (Eisler, tebrates, organochlorine insecticides manifest 1969b). their primary effects upon the nervous system (Negherbon, 1959; O'Brien, 1967), but acute toxicity of organophosphorus compounds is explained on the basis of inhibition of cholin esterase activity in vivo (Negherbon, 1959; SUMMARY AND CONCLUSIONS O'Brien, 1967; Holland et al., 1967), However, factors other than cholinesterase inhibition 1. Static assays with 12 insecticides and may be operating since large differences seven species of estuarine teleosts (American occurred among closely related species in eel, mummichog, striped killifish, bluehead, Ronald Eisler: Toxicities of Insecticides to Estuarine Fishes 11 striped mullet, Atlantic silverside and north REFERENCES ern puffer) were conducted for 96 hours at

24% 0 salinity, 20° C., and pH 8.0. American Public Health Association. 1960. Standard methods for the examination of water and waste-water. 11th edition. American 2. Endrin was consistently the most toxic Public Health Association. New York. 626 p. compound tested, and methyl parathion con sistently the least toxic. In order of compara Butler, P. A. tive toxicity at 96 hours, the 12 insecticides 1966. The problem of pesticides in estuaries. ranked: endrin, p,p'-DDT, dieldrin, aldrin, Transactions of the American Fisheries Society, dioxathion, heptachlor, lindane, methoxychlor, Supplement to Vol. 95, No. 4, p. 110-1150 Phosdrin, malathion, DDVP, and methyl parathion. This sequence was the same for Clark, J. R., and R. Eisler. all species assayed as determined by statis 1964. Sea water from ground sources. !!! u.s. Bu tical rank correlation analyses. reau of Sport Fisheries and Wildlife, Research Report 63, p. 173-184.

3. The 96 hour LC50 values in ppb, ranged Cope, o. B. between 0.05 and 3.1 with endrin, 0.4 and 89 19650 Agricultural chemicals and fresh water with p,p'-DDT, 0.9 and 34 with dieldrin, 6 and ecological systems. !£.Research in Pesticides. 75 wfth-dioxathion, 0.8 and 194 with heptachlor, Academic Press, New York, p. 115-127. 9 and 66 with lindane, 12 and 150 with methoxy chlor, 65 and 800 with Phosdrin, 27 and 3,250 Dawsey, L. H. 1964. Pesticide reference standards of the Ento with malathion, 225 and 2,680 with DDVP, and mological Society of America. Bulletin of the 5,200 and 75,800 with methyl parathion. Inter Entomological Society of America, Vol. 10, No. 2, species differences in several parameters, p. 95-103. especially total biomass per assay container, precluded meaningful comparisons of species Eisler, R. susceptibility. 1967. Tissue changes in puffers exposed to methoxychlor and methyl parathion. U.S. Bu reau of Sport Fisheries and Wildlife, Technical Paper l 7. 15 p. 4. The range in lethal activity of the test 1968. Pesticides in the marine environment. insecticides is small. Data from this and other Underwater Naturalist, Vol. 5, No. 2, p. 11-13. l 969a. Acute toxicities of insecticides to marine studies with different species indicated that decapod crustaceans. Crustaceana, Vol. 16, values for the ratio LC25 (96h) / LC50 (96h) No. 3, p. 302-310. fell between 0.15 and 0.64; similar values for l 969b. Factors affecting pesticide-induced toxi the ratio LC75 (96h) / LC50 (96h) ranged from city in an estuarine fish. U.S. Bureau of Sport 1.5 to 3.0. Fisheries and Wildlife, Technical Paper 45. Eisler, R.. and P. H. Edmunds. 1966. Effects of endrin on blood and tissue chem istry of a marine fish. Transactions of the 5. Upon comparing the relative toxicity of American Fisheries Society, Vol. 95, No. 2, organochlorine insecticides to marine organ p. 153-159. isms, I concluded that teleosts were less re sistant than mollusks and about equal in sen Eisler, R., and M. P. Weinstein. sitivity to decapod crustaceans. In sensitivity 1967. Changes in metal composition of the quahaug to organophosphorus compounds, teleosts were clam, Mercenaria mercenaria, after exposure to insecticides. Chesapeake Science, Vol. 8, No. 4, intermediate between the relatively resistant p. 253-258. mollusks and the highly susceptible crus taceans. It is recommended that future marine Henderson, c .• and Q. H. Pickering. toxicity assays should use species from a 1958. Toxicity of organic phosphorous insecticides minimum of three widely divergent groups to fish. Transactions of the American Fisheries including teleosts, crustaceans, and mollusks. Society, Vol. 87, p. 39 ..51. 12 Technical Paper 46: Bureau of Sport Fisheries and Wildlife

Henderson. c., Q. H. Pickering. and C. M. Tarzwell. Negherbon, w. o. 1959. Relative toxicity of ten chlorinated hydro 1959. Handbook of Toxicology. Vol. 111. Insecti carbon insecticides to four species of fish. cides, a compendium. National Academy of Transactions of the American Fisheries Society, Sciences, Division of Biology and Agriculture. Vol. 88, No. 1, p. 23-32. 854 p. 1960. The toxicity of organic phosphorous and chlorinated hydrocarbon insecticides to fish. In O'Brien, R. D. Biological Problems in Water Pollution. Trails: 1967. Insecticides, action and metabolism. Aca demic Press, New York, 332 p. actions of the 1959 Seminar. u.s. Public Health Service Technical Report W60-3, p. 76-88. Pickering, Q. H., c. Henderson. and A. E. Lemke.

19620 The toxicity of organic phosphorus insecti cides to different species of warmwater fishes. Holland, H. T., D. L. Coppage, and P. A. Butler. Transactions of the American Fisheries Society, 1967. Use of fish brain acetylcholinesterase to Vol. 91, No. 2, p. 175-1840 monitor pollution by organosphosphorous insec ticides. Bulletin of Environmental Contamination Snedecor, G. w. and Toxicology, Vol. 2, No. 3, p. 156-162. 19550 Statistical Methods. Iowa State College Press, Ames. 485 p. LUdemann. V. D., and H. Neumann. 1962. Uber die Wirkung der neuzeitlichen Kontak Tarzwell, c. M. tinsektizide auf die Tiere des SUsswasseres. 1963. Hazards of pesticides to fishes and the Anzeiger fur Schadlingskunde, Vol. 35, No. 1, aquatic environment. In Pesticides-their use and p. 5-9. effect. New York State Joint Legislative Com mittee on Natural Resources, Albany, N. Y., p. 30-41.

Murphy, s. D., R.R. Lauwerys, and K. L. Cheever. 19650 The toxicity of synthetic pesticides to 1968. Comparative anticholinesterase action of aquatic organisms and suggestions for meeting organosphosphorus insecticides in vertebrates. the problem. Proceedings of the 1964 Symposium Toxicology and Applied Pharmacology, Vol. 12, of the British Ecological Society, Ecology and

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