Ecological Research Series CHRONIC TOXICITY OF METHOXYCHLOR, MALATHION, AND CARBOFURAN TO SHEEPSHEAD MINNOWS (Cyprinodon variegatus) Environmental Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Gulf Breeze, Florida 32561 ------- RESEARCH REPORTING SERIES Research reports of the Office of Research and Development, U.S. Environmental Protection Agency, have been grouped into nine series. These nine broad cate- gories were established to facilitate further development and application of en- vironmental technology. Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields. The nine series are: 1. Environmental Health Effects Research 2. Environmental Protection Technology 3. Ecological Research 4. Environmental Monitoring 5. Socioeconomic Environmental Studies 6. Scientific and Technical Assessment Reports (STAR) 7. Interagency Energy-Environment Research and Development 8. "Special" Reports 9. Miscellaneous Reports This report has been assigned to the ECOLOGICAL RESEARCH series. This series describes research on the effects of pollution on humans, plant and animal spe- cies, and materials. Problems are assessed for their long- and short-term influ- ences. Investigations include formation, transport, and pathway studies to deter- mine the fate of pollutants and their effects. This work provides the technical basis for setting standards to minimize undesirable changes in living organisms in the aquatic, terrestrial, and atmospheric environments. This document is available to the public through the National Technical Informa- tion Service, Springfield, Virginia 22161. ------- CHRONIC TOXICITY OF METHOXYCHLOR, MALATHION, AND CARBOFURAN TO SHEEPSHEAD MINNOWS (Cyprinodon variegatus) by Patrick R. Parrish, Elizabeth E. Dyar, Mark A. Lindberg, Chiara M. Shanika, and Joanna M. Enos EG&G, Bionomics Marine Research Laboratory Pensacola, Florida 32507 Contract No. 68-03-0264 Project Officer David J. Hansen Environmental Research Laboratory Gulf Breeze, Florida 32561 ENVIRONMENTAL RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U. S. ENVIRONMENTAL PROTECTION AGENCY GULF BREEZE, FLORIDA 32561 ------- DISCLAIMER This report has been reviewed by the Gulf Breeze Environmen- tal Research Laboratory, U. S. Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the U. S. Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. ------- FOREWAKD The protection of our estuarine and coastal areas from damage caused by toxic organic pollutants requires that regulations restricting the introduction of these compounds into the environment be formulated on a sound scientific basis. Accurate information describing dose-response relationships for organisms and ecosystems under varying conditions is required. The Environmental Research Laboratory, Gulf Breeze, contributes to this information through research programs aimed at determining: the effects of toxic organic pollutants on individual species and communities or organisms; the effects of toxic organics on ecosystem processes and components; the significance of chemical carcinogens in the estuarine and marine environments. This report describes effects of three insecticides in partial life- cycle tests with an estuarine fish, the sheepshead minnow. The data will be useful in establishing estuarine water quality criteria, and limiting effluents containing carbofuran, malathion, or methoxychlor. Thomas W. Duke Director Environmental Research Laboratory iii ------- ABSTRACT Sheepshead minnows (Cyprinodon variegatus) were exposed to each of three pesticides—methoxychlor, malathion, and carbofu- ran—in flowing seawater to determine the acute and chronic (par- tial life-cycle) effects. The calculated 96-hour LCSO's and 95% confidence limits, based on measured concentrations, were: methoxychlor, 49 micrograms per liter (yg/£), 37-65 yg/£; mala- thion, 51 yg/£, 41-63 yg/£; and carbofuran, 386 yg/fc, 311-480 ygA. Mortality of adult sheepshead minnows exposed to mean mea- sured concentrations of methoxychlor >23 yg/£ was significantly (P<0.05) greater than mortality of control fish during the 140- day study- Further, hatching success of fry from eggs spawned by fish exposed to 23 yg/£ was significantly less than hatching success of control fry- The maximum acceptable toxicant concen- tration (MATC) was estimated to be >12<23 yg/£ and the applica- tion factor limits were 0.24-0.47. Mortality of adult sheepshead minnows exposed to mean mea- sured concentrations of malathion >18 yg/£ was significantly greater than mortality of control fish during the 140-day study- Mortality of fry hatched from eggs spawned by fish exposed to 9 and 18 yg/£ was significantly greater than mortality of control fry. The MATC was estimated to be >4<9 yg/& and the application factor limits were 0.08-0.18. Mortality of adult sheepshead minnows exposed to mean mea- sured concentrations of carbofuran >49 yg/£ was significantly greater than mortality of control fish during the 131-day study. Hatching success of fry from eggs spawned by fish exposed to 49 yg/£ was significantly less than hatching success of control fry. Also, mortality of fry hatched from eggs spawned by fish exposed to ?3 and 49 yg/£ was significantly greater than control fry mortality. The MATC was estimated to >15<23 yg/£ and the appli- cation factor limits were 0.04-0.06. This report was submitted in fulfillment of Contract Number 68-03-0264 by EG&G, Bionomics Marine Research Laboratory, under the sponsorship of the U.S. Environmental Protection Agency. This report covers the period 23 May 1973 to 23 May 1975; work was completed on 1 November 1976. IV ------- CONTENTS Foreword iii Abstract iv Tables vi Acknowledgment ix 1. Introduction 1 2. Conclusions 3 3. Recommendations 4 4. Materials and Methods Test materials 5 Test water 5 Test animals 6 Test methods 7 Chemical analyses 9 Statistical analyses 13 5. Results and Discussion Chemical analyses 14 Acute toxic ity 18 Chronic toxicity 19 Application factors 30 Summary 31 References 33 ------- TABLES Number Page 1 Nominal and Measured Concentrations of Methoxychlor during Acute and Chronic Exposures of Sheepshead Minnows (Cyprinodon variegatus) in Flowing Sea- water 14 2 Nominal and Measured Concentrations of Malathion during Acute and Chronic Exposures of Sheeps- head Minnows (Cyprinodon variegatus) in Flowing Seawater 15 3 Nominal and Measured Concentrations of Carbofuran during Acute and Chronic Exposures of Sheepshead Minnows (Cyprinodon variegatus) in Flowing Sea- water 16 4 Analysis of Parent and Hydrolyzed Carbofuran in Sea- water Samples Collected from the Nominal Concen- tration of 500 yg/& during a 131-Day Exposure of Sheepshead Minnows (Cyprinodon variegatus) 16 5 Acute Toxicity of Three Pesticides to Sheepshead Minnows (Cyprinodon variegatus) Exposed in Flow- ing Seawater 18 6 Percentage Mortality of Parental Sheepshead Minnows (Cyprinodon variegatus) Exposed to Methoxychlor in Flowing Seawater 19 7 Growth of Sheepshead Minnows (Cyprinodon variegatus) Exposed for 140 Days to Methoxychlor in Flowing, Natural Seawater ..... 20 * 8 Number of Eggs Spawned by Sheepshead Minnows (Cyprinodon variegatus) Exposed to Methoxychlor in Flowing, Natural Seawater during Three 10-Day Spawning Periods 21 9 Number of Eggs Spawned per Day per Female Sheeps- head Minnow (Cyprinodon variegatus) Exposed to Methoxychlor in Flowing, Natural Seawater during Three 10-Day Spawning Periods 22 vi ------- Number Page 10 Hatching Success of Fry from Eggs Spawned by Sheeps- head Minnows (Cyprinodon variegatus) Exposed to Methoxychlor in Flowing, Natural Seawater 23 11 Percentage Mortality, Average Standard Length, and Weight (Determined In Water) of 28-Day Old Sheeps- head Minnow (Cyprinodon variegatus) Fry Hatched from Eggs Spawned by Fish Exposed to Methoxychlor for 54-63 Days 23 12 Concentrations of Methoxychlor in Surviving Adult Sheepshead Minnows (Cyprinodon variegatus) Ex- posed for 140 Days 24 13 Accumulation of Organochlorine Pesticides by Marine Fishes 24 14 Percentage Mortality of Sheepshead Minnows (Cyprinodon variegatus) Exposed to Malathion in Flowing, Natural Seawater for 140 Days 25 15 Growth of Sheepshead Minnows (Cyprinodon variegatus) Exposed for 140 Days to Malathion in Flowing, Nat- ural Seawater 25 16 Number of Eggs Spawned by Sheepshead Minnows (Cyprinodon variegatus) Exposed to Malathion in Flowing, Natural Seawater during Two 10-Day Spawn- ing Periods 26 17 Number of Eggs Spawned per Day per Female Sheeps- head Minnow (Cyprinodon variegatus) Exposed to Malathion in Flowing, Natural Seawater during Two 10-Day Spawning Periods 26 18 Hatching Success of Fry from the Eggs Spawned by Sheepshead Minnows (Cyprinodon variegatus) Ex- posed to Malathion in Flowing, Natural Seawater. . . 27 19 Percentage Mortality, Average Standard Length, and Weight (Determined In Water) of 28-Day Old Sheeps- head Minnow (Cyprinodon variegatus) Fry Hatched from Eggs Produced by Fish Exposed to Malathion for 87-96 Days 27 20 Percentage Mortality of Sheepshead Minnows (Cyprinodon variegatus) Exposed to Carbofuran in Flowing, Syn- thetic Seawater 28 VI1 ------- N umber Pagt 21 Growth of Sheepshead Minnows (Cyprinodon variegatus) Exposed for 131 Days to Carbofuran in Flowing, Synthetic Seawater . •• 28 22 Number of Eggs Spawned by Sheepshead Minnows (Cyprinodon variegatus) Exposed to Carbofuran in Flowing, Synthetic Seawater 29 23 Hatching Success of Fry from Eggs Spawned by Sheeps- head Minnows (Cyprinodon variegatus) Exposed to Carbofuran in Flowing, Synthetic Seawater 29 24 Percentage Mortality and Average Standard Length of 30-Day Old Sheepshead Minnow (Cyprinodon variegatus) Fry which were Hatched from Eggs Spawned by Fish Exposed to Carbofuran for 42-95 Days in Flowing, Synthetic Seawater , . 30 25 Concentrations (yg/£) of Three Pesticides Toxic to Sheepshead Minnows (Cyprinodon variegatus) in Acute and Chronic Tests, and the Relationship of Acute Toxicity to Chronic Toxicity 30 26 Comparison of Acute and Chronic Malathion Toxicity to Two Freshwater Fishes and a Saltwater Fish. ... 31 27 Summary of Significant Effects of Methoxychlor, Malathion, and Carbofuran on Sheepshead Minnows (Cyprinodon variegatus) during Chronic Exposures in Flowing Seawater. , 32 Vlll ------- ACKNOWLEDGMENTS We thank the Project Officer, Mr. David J. Hansen, for his guidance and patience during these studies. Thanks to Mr. Terry A. Hollister, EG&G, Bionomics Marine Research Laboratory, for his help with statistical analyses, and thanks to Ms. Susan Walker for typing the manuscript. The assistance of Mr. Kenneth S. Buxton, EG&G, Bionomics Analytical Chemistry Laboratory, -is appreciated, as is the review of the manuscript by Kenneth J. Macek, Ph.D., and Sam R. Petrocelli, Ph.D., EG&G, Bionomics Aquatic Toxicology Laboratory. IX ------- SECTION I INTRODUCTION These studies were undertaken to gain information about the effects of three pesticides—methoxychlor, malathion, and carbo- furan—on sheepshead minnows (Cyprinodon variegatus), a saltwater fish. Data from these studies can be used to derive application factors, first described by Mount and Stephan (1967). An appli- cation factor is obtained by dividing the concentration consid- ered to be "safe" over a long period by a short-term toxicity value. The application factor may then be used to establish wa- ter quality criteria for each pesticide. The use of sheepshead minnows for long-term, life-cycle tests was proposed by Schimmel and Hansen (1975) and a tentative method was described by Hansen and Schimmel (1975). In our short term studies, data on 96-hour LCSO's (the concentration of each pesticide estimated to be lethal to 50% of the test animals after 96 hours of exposure) were ob- tained. In our long-term studies, parental sheepshead minnows were exposed for 28 days or more and then effects on spawning and progeny were determined. "Safe" concentrations were esti- mated after evaluation of data on number of eggs spawned by pa- rental fish, hatching success of embryos, mortality of fry, and growth of fry. Methoxychlor is a stable, chlorinated hydrocarbon compound used to control a wide variety of insects which attack fruits, vegetables, field and forage crops, and livestock. It is also used to control certain household and industrial insects. Me- thoxychlor is a replacement for DDT in many applications (Anon- ymous, 1972). Methoxychlor is ostensibly insoluble in water but soluble in lipids (Gardner and Bailey, 1975) and thus might be expected to accumulate in fish and to be cumulatively toxic dur- ing long-term exposure. A recent publication (Gardner and Bailey, op. cit.) provides an excellent overview of the effects of methoxychlor on environ- mental quality and states that although there are variances in estimates of the acute toxicity of methoxychlor to fishes, all reported LCSO's ranged from 5-80 micrograms per liter (pg/fc), ex- cepting three. We know of only one chronic (partial life-cycle) toxicity study that has been conducted with methoxychlor and fish (Merna and Eisele, 1973). Data from that study were insufficient for ------- deriving an application factor. Malathion is an organophosphate pesticide used throughout the U. S. to control a variety of pests. A major use of mala- thion is for mosquito control in both freshwater and estuarine areas. Several studies (Parkhurst and Johnson, 1955; Westman and Compton, 1960; Weiss, 1961; Lewallen and Wilder, 1962; Holland and Lowe, 1966; Wellborn, 1971; and Post and Schroeder, 1971) have shown that malathion is acutely lethal to a variety of freshwater and saltwater fishes under both field and labora- tory test conditions. Sublethal effects (avoidance and inhibi- tion of brain acetylcholinesterase) have also been observed in fashes exposed to malathion (Hansen e,t al., 1972; Coppage, 1972; and Coppage and Matthews, 1972). Chronic studies have been conducted with malathion and two freshwater fishes, fathead minnows (Pimephales promelas) (Mount and Stephan, 1967), and bluegill (Lepomis macrochirus) (Eaton, 1970). The studies showed the application factor limits for the two fishes to be very similar, ranging from 0.02-0.06. Carbofuran is a carbamate pesticide utilized both as a con- tact poison or as a soil-applied systemic poison. It is regis- tered for soil-applied use on a variety of crops, including rice, and for direct use on several insects, including mosquitoes (Anonymous, 1971). Little research has been performed on the effects of carbofuran on aquatic organisms. Carbofuran was the first compound tested. Tests were con- ducted from March-July 1974 in the EG&G, Bionomics Aquatic Toxi- cology Laboratory, Wareham, Massachusetts. Our new laboratory was opened in January 1975, and tests with methoxychlor and mala- thion were conducted from June-October 1975, at EG&G, Bionomics Marine Research Laboratory, Pensacola, Florida. ------- SECTION 2 CONCLUSIONS Sheepshead minnows (Cyprinodon variegatus) are suitable test animals for toxicity tests which include the reproductive portion of the life cycle and the critical life stages (embryos and fry) of the successive generation. Tests with these saltwater fish are practical means of de- termining maximum acceptable toxicant concentrations and appli- cation factors because of (a) the amenability of sheepshead minnows to laboratory culture and (b) the relatively short peri- od of time required to reach sexual maturity and complete the reproductive phase of the life cycle. The application factor limits derived for sheepshead minnows exposed to malathion are very similar to the application factor limits derived for two freshwater fishes, indicating that this saltwater fish may be used effectively to obtain data on which to base water quality criteria. ------- SECTION 3 RECOMMENDATIONS Spawning groups comprising five sheepshead minnows in the ratio of 3 female fish:2 male fish are satisfactory to determine spawning success. A 10-day spawning period for a spawning group is sufficient to monitor spawning success. Studies should be conducted with sheepshead minnows and other toxicants in chronic (full life-cycle) tests because tests with this saltwater fish appear to provide accurate estimates of MATC's in a shorter time and with less effort than do tests with most freshwater fishes. ------- SECTION 4 MATERIALS AND METHODS TEST MATERIALS Methoxychlor used in this study was obtained from E. I. du Pont de Nemours & Company, Biochemicals Department, Wilmington, Delaware. It was contained in a plastic jar labeled "Methoxy- chlor Technical, 1 Kg." Although active ingredient was not listed on the label, a technical data sheet dated April 1972 which accompanied the chemical stated that "...methoxychlor tech- nical. . .contains 88% (minimum) 2,2-bis-(p-methoxyphenyl)-1, 1, 1-trichloroethane and 12% (maximum) other isomers and reaction products. Malathion was obtained from the American Cyanamid Company, Agricultural Division, Princeton, New Jersey. It was contained in a metal bottle, apparently aluminum, with a transluscent cap. The bottle was refrigerated at all times. The material was la- beled "MALATHION Technical, Active Ingredient: Malathion* 95%; Inert Ingredients 5%. *0,0-dimethyl phosphorodithioate of di- ethyl mercaptosuccinate; (1 Gallon contains 9.7 Ib of malathion)." Carbofuran was obtained from FMC Corporation, Agricultural Chemical Division, Middleport, New York. It was contained in a plastic bag labeled "Carbofuran Technical (99%), FURADAN® In- secticide, Mr L514, 2Kg. C4717-54-A, 9/14/73." Concentrations of each pesticide are reported here as micro- grams (yg) of the technical material described above per liter (£) of seawater. Stock solutions of all three pesticides were prepared on a weight:volume basis by dissolving them in reagent grade acetone. These I-I stock solutions were placed in amber glass bottles and stored in the laboratory. New stock solutions were prepared as required. TEST WATER Methoxychlor and Malathion All water used for holding, acclimation, and testing was natural seawater which was pumped from Big Lagoon into the ------- laboratory- The pump intake was 85 meters (m) offshore at a depth of approximately 3 m. Water was pumped by a #316 stain- less steel pump through hard polyvinylchloride (PVC) pipes into an elevated fiberglass reservoir. En route, the water passed through a fiberglass, sand filter and a 10-micrometer (ym) poly- propylene bag filter. From the reservoir, in which the water was continuously and vigorously aerated, water flowed by gravity through PVC pipes to the diluters. No attempt was made to alter the salinity of the water, but temperature was maintained at 30±1 degrees Celsius (°C) by heat- ing the incoming seawater in small fiberglass-coated plywood boxes above the diluters with electric quartz heaters and by placing test aquaria in constant-temperature water baths. Carbofuran All water used for holding, acclimation, and testing was synthetic seawater, formulated according to the methods of LaRoche et al. (1970). Freshwater was pumped from a 120-m deep bed-rock well at the Wareham, Massachusetts, laboratory into two l,500-& fiberglass tanks. Ingredients were added, mixed with freshwater, and aerated. Water was drained from one tank at the rate of approximately 1,200 a per day until it was empty. Then, water was drained from the second tank while fresh synthetic sea- water was being prepared in the first tank. All water flowed by gravity through PVC pipes to the diluter. Temperature was maintained at 30±1°C by placing the test aquaria in constant-temperature water baths. TEST ANIMALS Methoxychlor and Malathion All sheepshead minnows used in these studies were collected from Big Lagoon, near Bionomics Marine Research Laboratory. They- were held in sand-banked ponds on the laboratory grounds and in fiberglass tanks in the laboratory. All fish were acclimated to test conditions for 14 days before testing according to the con- ditions of U. S. Environmental Protection Agency (1975). Mor- tality was <3% during acclimation. During holding and acclilfta- tion, fish were fed frozen or live Artemia salina (San Francisco Bay Brand) which contained <0.1 yg/g of chlorinated hydrocarbon pesticides or polychlorinated biphenyls as determined by our electron-capture gas chromatograph analyses. Size of fish was: methoxychlor—acute test, 1.7-3.8 centi- meters (cm) standard length (SL) and chronic test, 1.0-1.9 cm SL and 0.15 g mean weight (determined in water); malathion—acute test, 0.8-1.8 cm SL and chronic test, 1.0-1.8 cm SL and 0.11 g mean weight (determined in water). ------- Carbofuran Fish were obtained from the U. S. Environmental Protection Agency's Gulf Breeze Laboratory, Sabine Island, Gulf Breeze, Florida, where they had spawned naturally in outside earthern ponds. Fish for the acute and chronic tests were 1.8-4.0 cm SL. TEST METHODS Acute Tests All procedures followed methods of APHA et al. (1976) and U. S. Environmental Protection Agency (1975) , except as stated. The 96-hour tests were conducted in an intermittent-flow system by-using a proportional diluter (Mount and Brungs, 1967) con- structed to deliver 1 Jl/cycle at a dilution ratio of 75%. The average number of cycles was approximately 5/hour, providing 99% replacement in 24 hours (Sprague, 1969) . A mechanical injector (manufactured by George Frasier, Duluth, MN), equipped with a 50-milliliter (m£) glass syringe and stainless steel needle, pumped methoxychlor, malathion, or carbofuran stock solution through polyethylene tubing to the mixing cell. Test containers were 30 X 30 X 61-cm glass aquaria. Each contained 20 fish and approximately 28 a of water. Chronic Tests The tests were conducted as described above except that the proportional diluter was constructed for 50% dilution. It de- livered 1 Jl/cycle at a rate of approximately 5 cycles/hour. For the methoxychlor and malathion tests, the diluter was modified 'to include a solvent control wherein the same volume of solvent/ carrier (acetone) was added to methoxychlor- or malathion-free seawater as was added to the highest pesticide concentration. One injector, equipped with a 30-m£ glass syringe and a stainless steel needle, metered the respective stock solutions through polyethylene tubing into the mixing chamber. A second injector, equipped with a 50-m.e, glass syringe with stainless steel needle, metered acetone to each solvent control. Maximum solvent concen- tration was 29 y£/£ (parts per million, ppm) . To begin each test, 20 acclimated fish were impartially se- lected and placed in the test aquaria (a total of 40 fish per treatment) after the toxicant delivery system had been opera- tional for several days. Fish were daily fed flaked commercial fish food (BiOrell® and Tetramin®) ad libitum. Salinity and dis- solved oxygen were measured daily throughout the tests. Light for all tests was provided by two 3.7-m fluorscent bulbs sus- pended 46 cm above the test containers, providing approximately 1,100 lux incident to the water surface. Photoperiod was 16 hours light, 8 hours dark. Survival was monitored daily by vi- sually inspecting each test container. Growth was monitored bi- weekly according to the photographic method of McKim and Benoit ------- (1971) and average weight was determined monthly by weighing each group in water. Effects of each pesticide on.-spawning were determined after fish began to exhibit signs of sexual maturity. Methoxychlor and Malathion— Monitoring of spawning activity was begun on day 54 of the methoxychlor test and on day 87 of the malathion test. Spawning chambers were constructed by lacing pieces of 6.5-millimeter (mm) square mesh #316 stainless steel screen together with #316 stain- less steel wire. The chambers were 30.5-cm square X 25.5-cm high, and were supported by 5-cm high extensions of the screen ends. Beneath each spawning chamber, a 29.5-cm square X 4.7-cm high egg collection tray was placed to retain the demersal eggs that sank through the bottom of the spawning chamber. The tray was constructed of plate glass and silicone sealant, with a 4-cm wide strip of 480-ym square mesh nylon screen along one side of the bottom to facilitate consolidation of eggs. Spawning groups, which consisted of two male and three female fish, were placed in the spawning chambers for a 10-day period. All possible 2:3 ratios in each aquarium were spawned once and extra, unspawned fish from each replicate aquarium were combined whenever possible to form a 2:3 spawning group. Each day, one end of each spawning chamber was lifted slightly and the egg collection tray was re- moved from the aquarium. The eggs spawned during the previous 24 hours were washed with seawater, transferred by large-bore glass pipette into glass Petri dishes, counted, and separated into groups of 50 eggs. Each 50-egg group was placed in an egg incubator cup (a 100-m£ glass jar with the bottom cut off and 480-ym square mesh nylon screen attached with silicone sealant). Each egg cup was then placed in the same aquarium as the spawn- ing group which produced it. The egg incubator cups were sus- pended from a rocker-arm apparatus (Mount, 1968) which gently oscillated them in the test aquaria. Eggs were removed from each egg incubator by pipette daily, counted, and the cups washed with bursts of freshwater to clean the screens. This procedure was repeated until all living embryos hatched. Then, 40 fry were placed in glass chambers (14-cm wide X 20.5-cm high X 26-cm long with 381-ym square mesh #316 stainless steel screen over one end). Survival was monitored daily and growth (standard length anS av- erage weight) was measured after 28 days. At least two groups of fry per duplicate from each test concentration and controls were monitored, except in the higher concentrations where toxi- cant-induced mortality made it impossible to obtain spawning groups and subsequent eggs and fry. Carbofuran— Effects on spawning were determined by monitoring spawning activity of individual pairs of fish, beginning on day 28. Each pair was placed in a 14 X 25 X 25-cm glass and #316 stainless steel mesh spawning chamber similar to the fry chambers described ------- above. Spawning was monitored for a 62-day period, during which all possible pairs of unspawned fish in all duplicate aquaria were spawned. Eggs that sank through a false bottom of 7-mm square mesh #316 stainless steel screen were collected daily and treated as described above. CHEMICAL ANALYSES Seawater For each of the three acute tests, water was collected from each aquarium at the beginning and end of the 96-hour exposure. Water was collected from alternate duplicate aquaria weekly dur- ing the chronic tests. Water samples were prepared and analyzed as follows: Methoxychlor— Unfiltered seawater was extracted twice with two 50-m& por- tions of Nanograde® (Mallinckrodt) dichloromethane. Volumes ex- tracted were: Nominal concentration Volumes (yg/ft) (ma) 6 500 11 300 22 300 45 100 90 100 The combined extracts were dried by elution through anhydrous sodium sulfate (heated at 100°C for 24 hours), concentrated to approximately 1 m£ in a Kuderna-Danish evaporator, and solvent- exchanged with Nanograde petroleum ether. The extract volumes were adjusted to obtain a sensitivity of 0.05 ppm (nanograms [ng] per y£) by using a Perkin-Elmer Model 2100 gas chromatograph equipped with a Ni63 electron-capture detector. Operating conditions were: Column (glass)—2 m X 4 mm ID 3% OV-101 on 80/100 mesh Gas Chrom Q Oven temp.—210°C Detector temp.—275°C Injector temp.—250°C Carrier gas—Nitrogen Malathion— Unfiltered seawater samples of 500 m£ were extracted twice with two 50-m£ portions of Nanograde dichloromethane. The ex- tracts were dried by eluting through anhydrous sodium sulfate ------- (heated at 100°C for 24 hours) and concentrated in a Kuderna- Danish evaporator. The extract volumes were adjusted to obtain a sensitivity of 1.0 ppm by using a Perkin Elmer Model 2100 gas chromatograph equipped with a flame photometric detector oper- ating in the phosphorus mode. Operating conditions were: Column (glass)—2 m X 4 mm ID 3% OV-101 on 80/100 mesh Gas Chrom Q Oven temp.—210°C Bead setting—500 Injector temp.—250°C Carrier gas—10% argon/methane Carbofuran— Unfiltered water samples (approximately 500 nu) were mea- sured volumetrically in a graduated cylinder and placed in a l-£ separatory funnel equipped with a Teflon® stopcock. The water was extracted three times with separate 30-m& portions of Nano- grade dichloromethane and the combined extract was passed through an anhydrous sodium sulfate column to remove moisture from the solvent. The sodium sulfate was rinsed with a portion of di- chloromethane and the extract and rinse were placed in a Kuderna- Danish evaporator equipped with a three-ball Synder column. The solvent was evaporated to approximately 3 nU over an 80°C water bath, the extract was transferred to a 15-m& centrifuge tube with a Teflon-lined cap, and evaporated to dryness at room temperature by using a gentle stream of clean dry air. The extract was then dissolved in an accurately known volume of Nanograde benzene and stored in a freezer at 15°C prior to analysis by gas/liquid chro- matography under the following conditions: Instrument—Perkin-Elmer Model 3920 gas chromatograph Detector—Nitrogen/phosphorus thermionic detection Column—0.6 m X 2 mm ID glass packed with 20% SE-30 coated on 60/ 80 Chromasorb W. The column was conditioned at 235°C for two weeks prior to use. Several injections (3 X 50 y&) of Silyl-8, a column-silanizing agent, were made ovSr the two-week conditioning period. Gas flows—38 cubic centimeters (cc) N2/minute (min.) carrier, 7 cc H2/min. and 100 cc air/min. to the N/P detector. Temperatures—Injection port: 225°C Column: 155°C Transfer line: 245°C Recorder—Leeds & Northrup dual pen, 0-1 mV range, 5 mm/min. chart speed 10 ------- Response—30 ng of carbofuran and 80 ng of 3-hydroxycarbofuran gave half-scale response with retention times of 3.4 and 6.4 min., respectively Extraction efficiency and mean recovery for the analytical methods were 89.9±9.8% for methoxychlor, 84.5±11.7% for mala- thion, and 79.0±7.3% for carbofuran. Data in this report are corrected for recovery. Fish Tissue Fish were collected for residue analyses as follows: a. adults alive at the end of the respective exposure; b. fry alive at the end of the 28-day growth period; and c. eggs randomly collected during the spawning periods. Methoxychlor— Tissues were analyzed by an adaptation of the methods of U. S. Environmental Protection Agency (1971 and 1974). Fish tissue was weighed to the nearest 0.01 g in a beaker. The tis- sue was transferred to a 100-m2, graduated cylinder, which had been cut at the 80-mJi mark to reduce the height of the cylinder; the beaker was rinsed with dichloromethane, which was then added to the cylinder. The tissue was homogenized with approximately 30 m£ of dichloromethane for 20 seconds by using a Brinkman Polytron Homogenizer, Model PT 10/20. The homogenate was filtered through No. 3 Whatman paper in- to a clean beaker, approximately 30 m£ of dichloromethane was added to the graduated cylinder, and the Polytron probe was rinsed for approximately 10 seconds in the solvent while the homogenizer was operating at low speed. The probe rinse was added to the filter and finally the filter was washed with di- chloromethane . The solvent was evaporated to approximately 5 m£ over a steam bath, cooled, and evaporated to dryness at room tempera- ture by using a gentle stream of clean air. At this point the extract was cleaned by florisil column chromatography according to U. S. Environmental Protection Agency (1974). Methoxychlor eluted quantitatively from the 6% ether-in-petroleum ether frac- tion and was sufficiently free of interfering substances to permit analysis by electron capture detection. The 6% ethyl- petroleum ether fraction containing methoxychlor was evaporated to approximately 3 m£ in a Kuderna-Danish evaporator equipped with a three-ball Snyder column, and the unit was cooled to room temperature. The receiver was disconnected, the remainder of the solvent was evaporated to dryness at room temperature by using a gentle air flow, and a known volume of hexane was added to the 11 ------- receiver to dissolve the residue. An aliquot of the extract was analyzed by gas chromatography under the following operating conditions: Instrument—Tracer Model MT-550 gas chromatograph Detector—Electron capture with 15 millicuries of Ni63 Column—2 m X 2 mm ID glass packed with 3% OV-101 on 100/120 mesh HMDS-treated Supelcoport Cashflows—30 cc N2/min. carrier, 60 cc N2/min. scavenger Temperatures—Column: 200°C Inlet: 230°C Transfer: 270°C Detector: 302°C Recorder—Corning Model 841, 0-1 mV, 0.5 cm/min. chart speed Response—2.5 ng of methoxychlor gave half-scale pen deflection at an attenuation of 1.6 X 10~9 amperes Three fish, weighing approximately 1 g each, were spiked with 100 ng of methoxychlor and were analyzed by the above method. The average precentage recovery of methoxychlor was 100±4.6%. The analytical results were not corrected for re- covery which was considered quantitative. Malathion— Tissues were analyzed in the manner described for methoxy- chlor except that malathion eluted from the florisil column quantitatively in the 1:1 ethyl ether-in-petroleum ether frac- tion. An aliquot of the extract was analyzed by gas chromatog- raphy under the following operating conditions: Instrument—Perkin-Elmer Model 3920 gas chromatograph Detectors—Electron capture with 15 millicuries of Ni63 and nitrogen/phosphorus thermionic detection Effluent Splitter—10 parts to N/P and 3 parts to BCD Column—2 m X 2 mm ID glass packed with 3% Dexsil 300 GC on 80/ 100 mesh DMHS-treated Supelcoport Gas flows—36 cc N2/min. carrier, 7 cc N2/min. and 100 cc air/ min. to the N/P detector Temperatures—Injection port: 250°C Column: 220°C Transfer line and splitter: 265°C 12 ------- Recorder—Leeds & Northrup dual pen, 0-1 mV range, 1.0 cm/min. chart speed Response—0.30 ng of malathion gave half-scale recorder pen deflection using the N/P detector at an attenuation of 16 X 1. Retention time was 2.0 min. Three whole fish, weighing approximately 1 g each, were spiked with 100 ng of malathion and were analyzed by the above method. The average percentage recovery of malathion was 103± 6.8%. The analytical results were not corrected for recovery which was considered quantitative. Carbofuran— Results of previous research in which fish were continu- ously exposed to radiolabeled C14 carbofuran for 28 days indi- cated that the maximum tissue concentrations were reached within 3-10 days, after which an equilibrium concentration was observed. A concentration factor of 5-20X was calculated (FMC, 1976). In view of the rapid equilibrium, the low concentration factor, and the absence of a routine gas-chromatographic analytical method for fish tissues, fish from the carbofuran chronic test were not analyzed for residues. STATISTICAL ANALYSES In the acute tests, the LCSO's and 95% confidence limits were calculated by linear regression analysis after probit trans- formation (Finney, 1971) . In the chronic tests, differences between treatments were determined by chi-square (X2) and analysis of variance (Sokol and Rohlf, 1973). Differences were considered significant at the 95% (P<0.05) confidence level. Post-hoc tests were con- ducted on treatment means by using the Student-Newman-Keuls range test (Keuls, 1952). 13 ------- SECTION 5 RESULTS AND DISCUSSION CHEMICAL ANALYSES Mean measured concentrations of methoxychlor in seawater were from 57-109% of nominal during the 96-hour test and from 45-55% of nominal during the chronic test (TABLE 1). Because this chlorinated hydrocarbon pesticide is "essentially insoluble in water (0.10 mg/A @ 25°C)" (Anonymous, 1972) and because ex- posure to light and the addition of particulate matter and micro- organisms hastens its degradation (Gardner and Bailey.- 1975),, these mean measured concentrations were within an expected and acceptable range. TABLE 1. NOMINAL AND MEASURED CONCENTRATIONS OF METHOXYCHLOR DURING ACUTE AND CHRONIC EXPOSURES OF SHEEPSHEAD MIN- NOWS (CYPRINODON VARIEGATUS) IN FLOWING SEAWATER. Test Concentration (yg/l.) Nominal Measured 0 Acute Control 22 30 40 53 70 93 125 Chronic Control Sol. control 6 11 22 45 90 hour <0.01 13 11 25 33 26 67 62 Mean 0.2 _a 3 5 12 23 48 96 hour <0.01 21 29 26 35 54 86 209 S.D. ±0.5 — ±2 ±4 ±7 ±19 ±10 Mean _ 17 20 26 34 40 78 136 Range 0-2 - 1-7 2-18 4-30 9-85 34-53 % of nom. _ 77 67 65 64 57 84 109 % of nom. _ - 50 45 55 51 53 t samples 18 - 15 15 15 15 4 JNot analyzed. 14 ------- Malathion is readily soluble in water and mean measured concentrations during both the acute and chronic tests reflected this characteristic; concentrations were 72-143% of nominal (TABLE 2). TABLE 2. NOMINAL AND MEASURED CONCENTRATIONS OF MALATHION DUR- ING ACUTE AND CHRONIC EXPOSURES OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) IN FLOWING SEAWATER. Concentration (yg/£) Test Nominal Acute Control 22 30 40 53 70 94 125 Chronic Control Sol. control 4 8 15 30 60 Measured 0 hour <0.1 16 26 25 43 62 78 108 Mean <0.1 _a 4 9 18 37 86 96 hour <0.1 16 27 37 50 67 99 111 S.D. _ — ±2 ±4 ±6 ±12 ±15 Mean - _ 16 26 31 46 64 88 109 Range ' _ - 1-6 4-17 8-28 20-57 70-101 1 of nom. _ 72 87 78 89 91 95 87 '5 of nom. _ — 100 112 120 123 143 # samples 19 - 20 20 20 10 3 aNot analyzed. Mean measured concentrations of parent carbofuran were from 44-62% of nominal during the acute test and from 18-24% of nomi- nal during the chronic test (TABLE 3). Evaluation of the analy- ses of water samples collected during days 1-30 of the chronic test shows that concentrations of parent carbofuran were approxi- mately 40% of nominal. Thereafter, despite the use of a flowing- water exposure system, measured concentrations of parent material decreased to approximately 10% of nominal. Concurrently, however, we observed a pattern of increasing concentrations of hydrolyzed carbofuran derivitives (TABLE 4). The rapid decline of measured concentrations of parent material in the 4-day acute test and the stability of parent carbofuran in a stock solution over a 12-day period (confirmed by chemical analyses) is further evidence that carbofuran was degraded in seawater. 15 ------- TABLE 3. NOMINAL AND MEASURED CONCENTRATIONS OF CARBOFURAN DUR- ING ACUTE AND CHRONIC EXPOSURES OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) IN FLOWING SEAWATER. Concentration (yg/&) Test Nominal 0 Acute Control 420 560 750 1,000 1,300 Chronic Control Sol. Control 31 62 125 250 500 Measured hour cO.l 230 380 480 640 860 Mean <0.1 _a 6 15 23 49 100 96 hour <0.1 120 270 220 280 760 S.D. - ±4 ±11 ±21 ±44 ±93 Mean ' _ 175 325 350 460 810 Range ' 2-12 - 2-12 1-29 1-65 2-150 20-270 £ of nom. __ 44 58 47 46 62 \ of nom. _ - 19 24 18 20 20 # samples 7 - 7 10 12 12 10 aNot analyzed. TABLE 4. ANALYSIS OF PARENT AND HYDROLYZED CARBOFURAN IN SEA- WATER SAMPLES COLLECTED FROM THE NOMINAL CONCENTRATION OF 500 yg/£ DURING A 131-DAY EXPOSURE OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS). Test Day 12 27 34 41 55 62 70 76 84 105 Parent Carbofuran (yg/£;ppb) 200 120 210 79 29 37 28 38 85 20 Hydrolyzed Carbofurana <1.0 <1.0 6.1 <1.0 <1.0 2.1 9.5 10.0 17.0 18.1 aThe percentage recovery of the hydrolyzed carbofuran from water is unknown. Therefore, these values are relative to each other. 16 ------- Our justification for and methodology of determining the hydrolyzed products of carbofuran are as follow: Carbofuran and 3-hydroxycarbofuran were completly hydro- lyzed within 24 hours when saturated solutions were made pH 9.2 and stored at 25°C (FMC, 1969). Similar to the base-catalyzed degradation of Sevin® to 1-hydroxynaphthol, carbofuran was ex- pected to eliminate the methylcarbamate group to form an hydroxy- sub-stituent at the benzyl-oxygen. Therefore, an analytical pro- cedure featuring derivatization of 1-naphthol was utilized to verify any degradation products of carbofuran which possess ac- tive hydroxy-substituents. Parent carbofuran is not detected by this analyses since it does not contain the reactive hydroxy sub- stituent. Approximately 2 g of carbofuran were added to 300 m£ of nor- mal sodium hydroxide and heated to 60°C for six hours. The solu- tion was cooled, hydrochloric acid was added to adjust the solu- tion to pH 4.0, and the hydrolyzed carbofuran was extracted into methylene chloride. The solvent was evaporated and a portion of the hydrolyzed carbofuran was weighed and dissolved in benzene to produce the hydrolyzed carbofuran working standard solution. An analytical procedure (U. S. Environmental Protection Agency, 1974) designed for the gas chromatographic determination of 1-naphthol in urine, following derivatization with chloroace- tic anhydride, was utilized to verify the hydrolysis of carbo- furan. Working standards of hydrolyzed carbofuran were deriva- tized and chromatographed under operating conditions previously described (except by using electron capture detection) with the following results: Weight of hydrolyzed Peak height response (mm) Carbofuran/7 m£ benzene Retention~~\Retention (yg) time " 3'° min' time = 4'2 min< 0 4 1 5 2 6 5 15 10 31 3 9.5 18 41 116 An aliquot of the seawater sample extracts (see TABLE 4) was derivatized and the gas chromatograms were examined for the pre- sence of quantity of hydrolyzed carbofuran. A graph of peak height versus weight of hydrolyzed carbofuran was constructed, 17 ------- by using the peak eluting in 4.2 minutes, and any hydrolyzed carbofuran found was determined with the graph. The data are presented as relative concentrations found in the seawater since the extraction efficiency of the hydrolyzed carbofuran moiety from the seawater was unknown. The concentrations of hydrolyzed carbofuran in seawater continued to increase during the test period. It is important to note that sample extracts were not treated with an aqueous base, but were derivatized directly. Therefore, any hydrolysis product of carbofuran detected was extracted from the seawater sample. Additionally, parent carbofuran working standards sur- vived the derivatization procedure virtually unchanged and the peaks at 3.0 and 4.2 minutes due to hydrolyzed carbofuran were not observed. ACUTE TOXICITY The acute toxicity of methoxychlor and malathion to sheeps- head minnows was similar; carbofuran was one order of magnitude less toxic (TABLE 5). TABLE 5. ACUTE TOXICITY OF THEEE PESTICIDES TO SHEEPSHEAD MIN- NOWS (CYPRINODON VARIEGATUS) EXPOSED IN FLOWING SEA- WATER. SEAWATER FOR THE METHOXYCHLOR AND MALATHION TESTS WAS NATURAL; THAT FOR THE CARBOFURAN TEST WAS SYNTHETIC. CALCULATIONS WERE BASED ON MEASURED CON- CENTRATIONS OF EACH PESTICIDE. Compound Methoxychlor Malathion Carbofuran 96-hour LC50, \iq/H 49 51 386 95% confidence limits, pg/£ 37-65 41-63 311-480 Salinity (°/oo) 23 20 21 Temperature (°C) 30 29 22 The acute toxicity of methoxychlor to sheepshead minnows tested under dynamic conditions was within the range reported for other estuarine fishes under static conditions, where esti- mated 96-hour LCSO's ranged from 12-150 yg/&. In static tests with two cyprinodontid fishes, Eisler (1970) estimated 96-hour LC50 values of 30 and 36 yg/£ for the striped killifish (Fundulus majalis) and mummichog (F. heteroclitus), respectively. In flowing water tests, malathion was more acutely toxic to sheepshead minnows than to the freshwater fathead minnow (96- hour LC50 9,000 yg/£) (Mount and Stephan, 1967) or bluegill 18 ------- (96-hour LC50 108 yg/A) (Eaton, 1970). Similarly, sheepshead minnows were more sensitive than were all but one of the seven estuarine fishes tested under static conditions by Eisler (1970), including the striped killifish and mummichog, for which the 96- hour LCSO's were 250 and 240 vg/l, respectively. Carbofuran was of the same order of toxicity to sheepshead minnows as to three freshwater fishes tested under static condi- tions. Reported 96-hour TLM's (median tolerance limits; same as LC50) for rainbow trout (Salmo gardneri) , channel catfish (Ictalurus punctatus), and bluegill were 280, 210, and 240 yg/£, respectively (Anonymous, 1971). CHRONIC TOXICITY Methoxychlor Methoxychlor affected parental fish in the 140-day study. Exposure to 48 yg/£ was lethal to 100% of the fish in one dupli- cate after 10 days and after 15 days in the other. Mortality of fish exposed to 23 yg/£ was significantly greater than mortality of control fish (TABLE 6). TABLE 6. PERCENTAGE MORTALITY OF PARENTAL SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO METHOXYCHLOR IN FLOWING SEAWATER. MORTALITY IS THE AVERAGE FROM DU- PLICATE AQUARIA AND DOES NOT INCLUDE DEATHS WHICH OC- CURRED IN THE SPAWNING CHAMBERS. Concentration (yg/&) Day 1-30 31-60 61-90 91-120 121-140 Control 0 0 0 0 0 Solvent Control 0 0 0 0 0 3 0 0 0 0 0 5 2 0 0 0 0 12 0 0 0 0 0 23. 10 8 2 0 0 48 100 - - - — Total 0 0020 20a 100a aSignificantly different from the control. Growth of parental fish exposed to methoxychlor was not significantly different from growth of control fish. Although growth was monitored biweekly, only measurements at the begin- ning, middle, and end of the exposure are presented (TABLE 7). 19 ------- TABLE 7. GROWTH OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED FOR 140 DAYS TO METHOXYCHLOR IN FLOWING, NAT- URAL SEAWATER. MEAN STANDARD LENGTH AND STANDARD DE- VIATION ARE GIVEN IN CENTIMETERS AND WERE DETERMINED PHOTOGRAPHICALLY. AVERAGE WEIGHT IS GIVEN IN GRAMS AND WAS DETERMINED IN WATER. Concentration (ygA) Control Sol. control 3 5 12 23 48 Day Length (cm) 1.4±0.2 1.4±0.2 1.4±0.2 1.4±0.2 1.5±0.2 1.5±0.3 1.5±0.2 0 Wt. (Sl 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Day 58 Length (cm) 2.9±0.2 2.8±0.3 2.8±0.3 2.7±0.3 2.8±0.3 2.8±0.4 ^a Wt. (g) 0.6 0.6 0.3 0.5 0.6 0.7 — Day Length (cm) 3.7±0.5 3.6±0.4 3.5±0.5 3.5±0.4 3.510.4 3.7±0.4 — 140 Wt. . IaL 1.3 1.2 1.2 1.0 1.2 1.5 — aAll fish had died. Fecundity (total eggs spawned) of exposed fish was not sig- nificantly different from that of control fish (TABLE 8). Be- cause female fish were killed by male fish in spawning chambers in all treatments except 23 yg/£, we calculated eggs per female spawning day- These values were obtained by dividing the num- ber of eggs obtained from a spawning chamber during a 24-hour period by the number of live female fish in the spawning chamber during the same period. There was no significant difference be- tween eggs per female spawning day in any treatment because of variability within the treatments, but fewer eggs were spawned per female spawning day by fish exposed to 5, 12, and 23 yg/£ than were spawned by control fish (TABLE 9). No female fish were killed by male fish in spawning chambers in 23 yg/£, although 1 to 6 females were killed in spawning cham- bers in lower concentrations and controls. Based on observations of fish in the spawning chambers, a probable reason is that ex- posure to 23 yg/fc of methoxychlor decreased aggressive spawning activity of male fish. Hatching success of fry from eggs spawned by fish exposed to 23 yg/£ of methoxychlor was significantly less than hatching success of control fry (TABLE 10). Neither fry mortality to 28 days posthatch nor growth of the fry was significantly affected by exposure to methoxychlor (TABLE 11). 20 ------- TABLE 8. NUMBER OF EGGS SPAWNED BY SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO METHOXYCHLOR IN 10-DAY SPAWNING PERIODS. WERE PLACED IN A SPAWNING FLOWING, NATURAL SEAWATER DURING THREE FIVE UNSPAWNED FISH (2 MALES AND 3 FEMALES) CHAMBER IN EACH DUPLICATE AQUARIUM, A AND B. Concentration Day Day 54 to 63 101 to 110 116 to 125 ™?!L TOTAL Control A B 443 253a 778 514 342a 413a 1,563 1,180 2,743 Solvent Control ABA 244a 809 746 86a 1,183 322 367a 934 528 697 2,926 1,596 3,623 3 B 921 a 991 793 2,705 4,301 (vgA) 5 12 A BAB 49 575 162 399 476 277a 94 384 563a 829 517 163a 1,088 1,681 773 946 2,769 1,719 23 A B 91 5 189 570 38 1,085 318 1,660 1,978 aDeaths occurred in spawning chamber. ------- TABLE 9. NUMBER OF EGGS SPAWNED PER DAY PER FEMALE SHEEPSHEAD MINNOW (CYPRINODQN VARIEGATUS) EXPOSED TO METHOXYCHLOR IN FLOWING, to NATURAL SEAWATER DURING THREE 10-DAY SPAWNING PERIODS. UNSPAWNED FISH (2 MALES AND 3 FEMALES) WERE PLACED IN A ING CHAMBER IN EACH DUPLICATE AQUARIUM, A AND B. FIVE SPAW Concentration (yg/£) Day 54-63 101-110 116-125 Mean of duplicate Mean of treatment Control A 15 26 16 19 B 11 17 15 14 17±5 Solvent Control A 12 5 12 10 B 27 39 31 32 21±13 3 A 25 11 18 18 25± 5 B 31 38 26 32 9 A 2 16 20 13 B 19 11 28 19 16±9 12 A B 5 13 3 13 17 8 8 11 10±5 23 A 3 6 1 3 B 0 19 26 18 11±14 ------- TABLE 10. HATCHING SUCCESS OF FRY FROM EGGS SPAWNED BY SHEEPS- HEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO METHOXYCHLOR IN FLOWING, NATURAL SEAWATER. MEAN PER- CENTAGE HATCH AND STANDARD DEVIATION REPRESENTS POOLED DATA FROM DUPLICATE AQUARIA DURING THREE 10-DAY SPAWN- ING PERIODS. Concentration (ygA) Mean percentage hatch and S.D. Numbers of eggs examined Sol Control . control 3 5 12 23 98±3 98±4 98±3 95±6 97±2 73±18a 1,200 2,040 2,400 1,450 700 1,055 aSignificantly different from the control. TABLE 11. PERCENTAGE MORTALITY, AVERAGE STANDARD LENGTH, AND WEIGHT (DETERMINED IN WATER) OF 28-DAY OLD SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS) FRY HATCHED FROM EGGS SPAWNED BY FISH EXPOSED TO METHOXYCHLOR FOR 54-63 DAYS. Concentration Sol (yg/£) Control . control 3 5 12 23 Number of fry 160 160 160 80 120 59 Mortality Length (%) (cm) 0 0 1 0 4 4 1. 1. 1. 1. 1. 1. 4±0. 4±0. 4±0. 3±0. 4±0. 5±0. 1 1 1 1 1 2 Weight (g) 0. 0. 0. 0. 0. 0. 07 05 07 06 06 06 Methoxychlor was accumulated by adult fish exposed continu- ously for 140 days. The pesticide was also accumulated in eggs spawned by these fish. Accumulation was dependent upon water concentration during exposure (TABLE 12). Concentration factors (based on measured water concentrations) ranged from 113-264. These values are much lower than concentration factors for other chlorinated hydrocarbon pesticides and marine fishes (TABLE 13). A maximum concentration of 1.1 yg/g was detected in eggs spawned by fish exposed to 12 23 ------- TABLE 12. CONCENTRATIONS OF METHOXYCHLOR IN SURVIVING ADULT SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED FOR 140 DAYS. MEAN TISSUE RESIDUES ARE WHOLE-BODY, WET-WEIGHT. DUPLICATE ANALYSES OF EACH POOLED SAMPLE (AT LEAST 2 FISH PER SAMPLE) WERE PERFORMED. Concentration Water (pg/£) Control Sol. control 3 5 12 23 Tissue (yg/g) <0.1 <0.1 0.3410.24 1.32±0.24 1.38+0.25 3.18+0.53 Concentration factor — - 113 264 115 138 Number of samples 4 4 6 6 6 6 TABLE 13. ACCUMULATION OF ORGANOCHLORINE PESTICIDES BY MARINE FISHES. CONCENTRATION FACTORS WERE DERIVED BY DI- VIDING CONCENTRATIONS IN FISH (WHOLE-BODY, WET-WEIGHT) BY CONCENTRATIONS IN TEST WATER. Concentration Pesticide Fish factor Exposure Source (maximum) (days) DDT Dieldrin Atlantic croaker Pinfish Spot 16,300a 40,000a 6,700b 21-35 14 35 Hansen and Wilson, 1970 Parrish et al. , 1973 Endrin Sheepshead minnows 4,800b 33 Schimmel et al. , •1975 ^Based on nominal water concentration. "Based on measured water concentration. Malathion Malathion affected survival of parental fish but did not affect their growth or fecundity (TABLES 14-17). Exposure to 86 yg/& was lethal to 100% of the fish in one duplicate and 95% 24 ------- in the other after 5 days; exposure to 37 v-g/t* was lethal to 100% in one duplicate and 80% in the other after 30 days. Exposure to 18 yg/£ was lethal to 50% of the fish in both duplicates af- ter 86 days. No deaths occurred in any concentration or control after day 90 of the 140-day study. TABLE 14. PERCENTAGE MORTALITY OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO MALATHION IN FLOWING, NATURAL SEAWATER FOR 140 DAYS. MORTALITY IS THE AVERAGE FROM DUPLICATE AQUARIA AND DOES NOT INCLUDE DEATHS WHICH OCCURRED IN THE SPAWNING CHAM- BERS. Concentration (pg/£) Day 1-30 31-60 61-90 91-120 121-140 Control 0 0 2 0 0 Solvent Control 0 0 0 0 0 4 0 0 5 0 0 9 0 0 0 0 0 18 5 23 22 0 0 37 90 8 2 — - 86 100 _ — — - Total 0 50C 100C 100' aSignificantly different from the control. TABLE 15. GROWTH OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED FOR 140 DAYS TO MALATHION IN FLOWING, NAT- URAL SEAWATER. MEAN STANDARD LENGTH AND STANDARD DEVIATION ARE GIVEN IN CENTIMETERS AND WERE DETER- MINED PHOTOGRAPHICALLY. AVERAGE WEIGHT IS GIVEN IN GRAMS AND WAS DETERMINED IN WATER. Concentration Day 0 Length Wt. Day 61 Day 140 Length Wt. Length Wt. Control Sol. control 4 9 18 37 86 1.4±0.2 1. 3±0.2 1.4±0.2 1.3±0.2 1.3+0.2 1.4±0.2 1.4±0.2 0.1 0.1 0.2 0.1 0.1 0.1 0.1 2.8±0.4 2.7±0.6 2.7±0.3 2.8±0.3 2.6±0.4 2.4±0.2 _b 0.7 0.8 0.7 0.7 0.6 0.5 - 4.1±0.4 4.1+0.5 3.9±0.4 3.9±0.4 3.7±0.3 _b - 1.4 1.4 1.2 1.3 _a _ - aAll fish were used for acetylcholinesterase inhibition analyses. bAll fish had died. 25 ------- TABLE 16. NUMBER OF EGGS SPAWNED BY SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO MALATHION IN FLOWING, NATURAL SEAWATER DURING TWO 10-DAY SPAWN- ING PERIODS. FIVE UNSPAWNED FISH (2 MALES AND 3 FEMALES) WERE PLACED IN A SPAWNING CHAMBER IN EACH DUPLICATE AQUARIUM, A AND B. Concentration (yg/Ji) Day 87-96 119-128 SUBTOTAL TOTAL Control A 154a 538 692 1, B 747a 258 1,005 697 Solvent Control A 111 364 1,141 2, B 626 325 951 092 A 422 535 957 2, 4 B 445 729 1,174 131 A 341 738 1,079 1, 9 B a 481a 390 871 950 18 A 299 _b 299 1, B 353 374a 727 026 aDeath(s) occurred in spawning chamber. spawning chamber; 50% mortality had occurred. TABLE 17. NUMBER OF EGGS SPAWNED PER DAY PER FEMALE SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS) EXPOSED TO MALATHION IN FLOWING, NATURAL SEAWATER DURING TWO 10-DAY SPAWN- ING PERIODS. FIVE UNSPAWNED FISH (2 MALES AND 3 FE- MALES) WERE PLACED IN A SPAWNING CHAMBER IN EACH DUPLICATE AQUARIUM, A AND B. Concentration (yg/£) Day 87-96 119-128 Average of duplicate Mean of treatment Control A B 11 30 18 9 14 20 17±9 Solvent Control A 26 12 19 18± B 21 11 16 7 4 A B 14 15 18 24 16 20 18±4 9 A B 16 21 25 13 20 17 19±5 18 A 10 _a 10 14± B 21 19 16 5 aNo spawning chamber; 50% mortality had occurred. Malathion did not affect hatching success of fry from eggs 26 ------- spawned (TABLE 18) but did affect the fry. Mortality of fry hatched from eggs spawned by fish exposed to 9 and 18 yg/£ of malathion was significantly greater than mortality of control fry. Growth of surviving fry was not affected (TABLE 19). TABLE 18. HATCHING SUCCESS OF FRY FROM EGGS SPAWNED BY SHEEPS- HEAD MINNOWS (CYPRINGDON VARIEGATU5) EXPOSED TO MALA- THION IN FLOWING, NATURAL SEAWATER. MEAN PERCENTAGE HATCH AND STANDARD DEVIATION REPRESENTS POOLED DATA FROM DUPLICATE AQUARIA DURING TWO 10-DAY SPAWNING PERIODS. Concentration (yg/£) Percentage hatch Number of eggs examined Control Sol. control 4 9 18 97±5 99±2 97±3 97±2 96±6 850 700 1,000 900 350 TABLE 19. PERCENTAGE MORTALITY, AVERAGE STANDARD LENGTH, AND WEIGHT (DETERMINED IN WATER) OF 28-DAY OLD SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS) FRY HATCHED FROM EGGS PRODUCED BY FISH EXPOSED TO MALATHION FOR 87-96 DAYS. Concentration (yg/£) Control Sol. control 4 9 18 Number of fry 160 160 160 160 120 Mortality (%) 7 10 9 14b 15b Length (cm) 1.0±0.2 _a 1.1±0.2 1.2±0.2 1.2±0.1 Weight (g) 0.04 0.03 0.04 0.04 0.03 ^No data. ^Significantly different from the control. Malathion was not detectable (<0.1 yg/g) in fish sampled at the end of the 140-day study- This is not surprising because fish readily convert malathion to the mono- and dicarboxylic acids of malathion (Cook and Moore, 1976). Carbofuran Carbofuran affected survival of parental fish exposed to the pesticide for 131 days. Exposure to 100 yg/£ was lethal to 27 ------- 100% of the fish in one duplicate and 95% in the other after 14 days. Mortality of fish exposed to 49 ppb was significantly greater than mortality of control fish after 30 days of exposure (TABLE 20). TABLE 20. PERCENTAGE MORTALITY OF SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO CARBOFURAN IN FLOWING, SYNTHE- TIC SEAWATER. MORTALITY IS THE AVERAGE FROM DUPLICATE AQUARIA AND DOES NOT INCLUDE DEATHS FROM SPAWNING ACTIVITY. Concentration (yg/S,) Day 1-30 31-60 61-90 91-131 Control 0 5 2 0 6 5 5 0 0 15 2 8 5 0 23 5 10 0 0 49 40 10 0 0 100 100 - - — Total 7 10 15 15 50a 100a aSignificantly different from the control. Carbofuran did not significantly affect growth of parental fish or number of eggs spawned in any concentration (TABLES 21- 22) . TABLE 21. GROWTH OF SHEEPSHEAD MINNOWS (CYPRINODQN VARIEGATUS) EXPOSED FOR 131 DAYS TO CARBOFURAN IN FLOWING, SYN- THETIC SEAWATER. MEAN STANDARD LENGTH AND STANDARD DEVIATION ARE GIVEN IN CENTIMETERS AND WERE DETER- MINED PHOTOGRAPHICALLY. .AVERAGE WEIGHT IS GIVEN IN GRAMS AND WAS DETERMINED IN WATER. Concentration (vgA) Control 6 15 23 49 100 Day 2 Length 2.9±0.4 3.8±0.5 3.1±0.4 2.810.4 2.8±0.5 3.010.5 Day 60 Length 3.8+0.3 3.610.4 3.6+0.3 3.210.4 3.310.3 _a Day Length 4.H0.3 4.010.2 3.9+0.3 3.810.3 3.7+0.5 — 131 Weight * 1.15 1.10 1.16 0.92 1.05 — aAll fish had died. 28 ------- TABLE 22. NUMBER OF EGGS SPAWNED BY SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO CARBOFURAN IN FLOWING, SYNTHETIC SEAWATER. ALL POSSIBLE PAIRS OF FISH IN EACH DUPLICATE AQUARIUM WERE SPAWNED. Concentration Number of eggs (yg/&) Replicate A Replicate B Total Control 6 15 23 49 650 854 848 475 248 449 852 1,295 820 154 1,099 1,706 2,143 1,295 402a aFifty percent mortality had occurred. Hatching success of fry from eggs spawned by fish exposed to 49 yg/£ was significantly less than hatching success of con- trol fry (TABLE 23). TABLE 23. HATCHING SUCCESS OF FRY FROM EGGS SPAWNED BY SHEEPS- HEAD MINNOWS (CYPRINODON VARIEGATUS) EXPOSED TO CAR- BOFURAN IN FLOWING, SYNTHETIC SEAWATER. MEAN PER- CENTAGE HATCH AND STANDARD DEVIATION REPRESENTS POOLED DATA FROM SPAWNING PAIRS IN DUPLICATE AQUARIA. Concentration Percentage Number of eggs (yg/&) hatch examined Control 6 15 23 49 98±3 99±3 96±10 98±2 86±10a 450 700 937 609 233 aSignificantly different from the control. Mortality of fry hatched from eggs spawned by fish exposed to 23 and 49 yg/2. was significantly greater than mortality of control fry. Growth of surviving fry in all concentrations was not affected, however (TABLE 24). 29 ------- TABLE 24. PERCENTAGE MORTALITY AND AVERAGE STANDARD LENGTH OF 30-DAY OLD SHEEPSHEAD MINNOW (CYRPINODON VARIEGATUS) FRY WHICH WERE HATCHED FROM EGGS SPAWNED BY FISH EX- POSED TO CARBOFURAN FOR 42-95 DAYS IN FLOWING, SYN- THETIC SEAWATER. MORTALITY AND LENGTH ARE AVERAGES OF FOUR GROUPS OF 40 FRY EXCEPT AS NOTED. Concentration (pgA) Control 6 15 23 49 Number of fry 160 160 160 120 80 Mortality (%) 5 2 8 12a 41a Length (cm) 1.4 r. 3 1.3 1.4 1.4 aSignificantly different from the control. APPLICATION FACTORS Application factors were calculated from the results of the acute and chronic toxicity tests (TABLE 25). TABLE 25. CONCENTRATIONS (yg/£) OF THREE PESTICIDES TOXIC TO SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) IN ACUTE AND CHRONIC TESTS, AND THE RELATIONSHIP OF ACUTE TOX- ICITY TO CHRONIC TOXICITY. 96-hour LC50 (95% confidence Application Pesticide limits) MATC limits factor limitsa Methoxychlor Malathion Carbof uran 49 (37-65) 51 (41-63) 386 (311-480) >12<23 >4<9 >15<23 0. 0. 0. 24-0. 08-0. 04-0. 47 18 06 aDerived by dividing the Maximum Acceptable Toxicant Concentra- tion limits by the 96-hour LC50. We find no application factors in the literature on which to base a comparison of the sensitivity of sheepshead minnows and any freshwater fish to methoxychlor or carbofuran. For 30 ------- malathion, however, studies by Mount and Stephan (1967) with fathead minnows and Eaton (1970) with bluegill show that the application factors derived for all three fishes were similar (TABLE 26). TABLE 26. COMPARISON OF ACUTE AND CHRONIC MALATHION TOXICITY TO TWO FRESHWATER FISHES AND A SALTWATER FISH. 96-hour LC50 (ygA) MATC limits (ygA) Application factors limits Fathead minnows a 9,000 200-580 0.02-0.06 Bluegillsb 108 4-7 0.04-0.06 Sheepshead minnows 51 4-9 0.08-0.18 aFrom Mount and Stephan, 1967. bFrom Eaton, 1970. SUMMARY 1. Carbofuran was less toxic to sheepshead minnows than were methoxychlor and malathion in acute tests. Estimated 96- hour LCSO's, based on average measured concentrations in water, were 386, 49, and 51 yg/£, respectively. 2. All three pesticides killed parental fish in concentrations <50 yg/£ during chronic tests, and the lowest concentrations of the pesticides in which toxic effects were observed were similar (TABLE 27). 3. The life stages of progeny from exposed parental fish that were sensitive to each pesticide were: methoxychlor—embryo; malathion—fry; and carbofuran—embryo and fry. 4. The relationship of acute toxicity and chronic toxicity for sheepshead minnows exposed to malathion (as expressed by ap- plication factors) was similar to that for two freshwater fishes exposed to malathion. 5. Sheepshead minnows are a suitable estuarine fish for toxi- city tests which include the reproductive portion of the life cycle and the first generation. 31 ------- TABLE 27. SUMMARY OF SIGNIFICANT EFFECTS OF METHOXYCHLOR, MALATHION, AND CARBOFURAN ON SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS) DURING CHRONIC EXPOSURES IN Methoxychlor Malathion Carbofuran FLOWING SEAWATER. Generation Life stage Parental Adult FI Embryo Parental Adult FI Fry Parental Adult FI Embryo Fry Effect Death Decreased hatch Death Increased mortality Death Decreased hatch Increased mortality Measured- concentration >23 23 >18 9 and 18 >49 49 23 32 ------- REFERENCES Anonymous. 1971. Furadan® Insecticide—Namaticide. FMC Cor- poration, Niagara Chemical Division, Middleport, New York. 22 p. Anonymous. 1972. Methoxychlor technical data sheet. E. I. du Pont de Nemours & Company, Biochemicals Department, Wilming- ton, Delaware. 4 p. APHA, AWWA, and WPCF. 1976. Standard methods for the examina- tion of water and wastewater. (Fourteenth edition.) American Public Health Association, Washington, D.C. 874 p. Cook, G.H., and J.C. Moore. 1976. Determination of malathion, malaoxon, and mono- and dicarboxylic acids of malathion in fish, oyster, and shrimp tissue. Agricultural and Food Chemistry, 24 (3) :631-634. Coppage, D.L. 1972. 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FMC Corporation, Agricul- tural Chemical Division, Middleport, New York. FMC. 1976. Personal communication. FMC Corporation, Agricul- tural Chemical Division,' Middleport, New York. Gardner, D.R., and J.R. Bailey. 1975. Methoxychlor: Its Ef- fects on Environmental Quality- NRCC/CNRC Ottawa, Canada. 164 p. Hansen, D.J., and A.J. Wilson. 1970. Significance of DDT resi- dues from the estuary near Pensacola, Fla. Pesticides Monitoring Journal, 4(2):51-56. Hansen, D.J., E. Matthews, S.L. Nail, and D.P. Dumas. 1972. Avoidance of pesticides by untrained mosquitofish, Gambusia affinis. Bulletin of Environmental Contamination and Toxi- cology, 8(1):46-51. Hansen, D.J., and S.C. Schimmel. 1975. An entire life-cycle bioassay using sheepshead minnows (Cyprinodon variegatus). Federal Register 40(123), part 11:26904-26905. Holland, H.T., and J.I. Lowe. 1966. Malathion: chronic effects on estuarine fish. Mosquito News, 26(3):383-385. Keuls, M. 1952. The use of the studentized range in connection with an analysis of variance. Euphytica, 1:112-122. LaRoche, G., R. Eisler, and C.M. Tarzwell. 1970. Bioassay pro- cedures for oil and dispersant toxicity evaluation. Journal Water Pollution Control Federation, 42(11):1,982-1,989. Lewallen, L.L., and W.A. Wilder. 1962. Toxicity of certain or- ganophosphorus and carbamate insecticides to rainbow trout. Mosquito News, 22(4):369-372. McKim, J.M., and D.A. Benoit. 1971. Effects of long term ex- posure to copper on survival, growth, and reproduction of brook trout, Salvelinus fontinalis. Journal Fisheries Re- search Board of Canada, 28(5):655-662. Merna, J.W., and P.J. Eisele. 1973. The effects of methoxychlor on aquatic biota. Ecological Research Series EPA-R3-73-046. 59 p. Mount, D.I., and W.A. Brungs. 1967. A simplified dosing appara- tus for fish toxicological studies. Water Research, 1:21-29. Mount, D.I., and C.E. Stephan. 1967. A method for establishing acceptable toxicant limits for fish - malathion and the bu- toxyethanol ester of 2,4-D. Transactions of the American Fisheries Society, 96 (2) :185-193. 34 ------- Mount, D.I. 1968. Chronic toxicity of copper to fathead minnows (Pimephales promelas, Rafinesque). Water Research, 2:215- 223. Parkhurst, Z.E., and H.E. Johnson. 1955. Toxicity of malathion 500 to Fall Chinook salmon fingerlings. The Progressive Fish Culturist, 17 (3) :113-116. Parrish, P.R., J.A. Couch, J. Forester, J.M. Patrick, Jr., and G.H. Cook. 1973. Dieldrin: effects on several estuarine organisms. Proceedings of the 27th Annual Conference of the Southeastern Association of Game and Fish Commissioners. p. 427-434. Post, G., and T. Schroeder. 1971. The toxicity of four insecti- cides to four salmonid species. Bulletin of Environmental Contamination and Toxicology, 6 (2) :144-155. Schimmel, S.C., and D.J. Hansen. 1975. Sheepshead minnows (Cyprinodon variegatus): an estuarine fish suitable for chronic (entire life-cycle) bioassays. Proceedings of" the 28th Annual Conference of Southeastern Association of Game and Fish Commissioners. p. 392-398. Schimmel, S.C., P.R. Parrish, D.J. Hansen, J.M. Patrick, Jr-. , and J. Forester. 1975. Endrin: effects on several estuarine organisms. Proceedings of the 28th Annual Conference of the Southeastern Association of Game and Fish Commissioners. (In press.) Sokol, R.R., and J.R. Rohlf. 1973. Introduction to Biostatis- tics. W.H. Freeman and Company, San Fransicso. 368 p. Sprague, J.B. 1969- I. Review Paper: measurement of pollutant toxicity to fish. I. Bioassay methods for acute toxicity. Water Research, 3(11):793-821. U.S. Environmental Protection Agency. 1971. Method for organic pesticides in water and wastewater. National Environmental Research Center, Cincinnati, Ohio. 57 p. U.S. Environmental Protection Agency. 1974. 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REPORT NO. ERL-GB-0010 3 RLCIPI ENT'S ACCtSSIO^* NO. TITLE AND SUBTITLE Chronic Toxicity of Methoxychlor, Malathion, and Carbofuran to Sheepshead Minnows (Cyprinodon variegatus) 6. Pi.RFORMING ORGANIZATION CODE AUTHOHI5) Patrick R. Parrish, Elizabeth E. Dyar, Mark A. Lindberg, Chiara M. Shanika, and Joanna M. Enos 0. PERFORMING ORGANIZATION RCPORT NO. PERFORMING ORGANIZATION NAME AND ADDRESS EG&G, Bionomics Marine Research Laboratory Route 6'-, Box 1002 Pensacola, Florida 32507 12..SPONSORING AGENCY NAME AND ADDRESS Environmental Research Laboratory Office of Research and Development U,S. Environmental Protection Agency Gulf Breeze, Florida 32561 . REPORT DAT E April 1977 (Issuing Date) 10. PROGRAM LLEM1NT NO. 1EA615 11. CONTRACT/GRANT NO. 68-03-0264 13. TYPE OF REPORT AND PERIOD COVf RED Final 14. SPONSORING AGENCY CODE EPA-ORD 15. SUPPLEMENTARY NOTES 16. ABSTRACT Sheepshead minnows (Cyprinodon variegatus) were exposed to each of three pesticides—methoxychlor, malathion, and carbofuran--in flowing sea water to determine the acute and chronic (partial life-cycle) effects. Mortality of adult fish exposed to concentrations of methoxychlor >23 yg/£ and hatching success of fry from eggs spawned by fish exposed to 23 yg/£ were significantly different from the control. The maximum ac- ceptable toxicant concentration (MATC) was estimated to be >12<23 yg/£; application factor (AF) limits were 0.24-0.47. Mortality of adult fish exposed to concentrations of malathion ~>18 ygA and mortality of fry hatched from eggs spawned by fish exposed to 9 and 18 yg/£ were significantly different from the control. The MATC was estimated to >4<9 yg/£; AF limits were 0.08-0.18. Mortality of adult fish exposed to concentrations of carbofuran >49 yg/&, hatching success of fry from eggs spawned by fish exposed to 49 vg/^f and mortality of fry hatched from eggs spawned by fish exposed to 23 and 49 ygA were significantly different from the control. The MATJC was estimated to >15<23 ygA; AF limits were 0.04-0.06. 17. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS Toxicity Fish Saltwater Pesticides Methoxychlor Malathion Carbofuran b. IDENTIFIERS/OPEN ENDED TERMS Chronic toxicity Flowing seawatfer Application factor i1. COSATI 1 i 13. DISTRIBUTION STATEMENT Release unlimited 10. SECURITY CLAbS / //llt'A'r/ Unclassified NO. Of F'AGt S 36 20 SECURITY CLASS t.Y'.'i/t / dy Unclassified ''.>. TRICE ------- |