Endosulfan: Another Organochlorine Pesticide Charlene Hurst

Physical & Chemical Properties Color: beige Physical State: crystalline-waxy solid Melting Point: 106 C Density: g/mL Lipophilic Beta form converts to alpha at high temps.

Applications & History First introduced 1956, called Thiodan® Organochlorine pesticide mainly for tobacco and fruits Used for control of over 100 insects Production in US stopped after 1982 Still used in chemical formulations in the US as a wettable powder and emulsifier for wood preservation, home gardening, agriculture million fish in Rhine died from exposure USGS

Chemistry 2 stereo isomers: alpha and beta Break down to: diol, sulfate, lactone, ether, hydroether Half life from 1-6 months in water to 2 years in soil Degraded in water to endosulfan diol, in soil to endosulfan sulfate

Environmental entry Some agricultural runoff Accidental spills Volatized into the atmosphere, transported No natural occurrence Detected: atmosphere, soil, sediment, surface water, rain water, food items Synergism with other toxicants? (ex. Dieldrin)

Organismal Entry Inhalation Absorption through skin Orally Target sites within body: fatty tissues, liver, kidneys

Toxic Effects Mammals less susceptible than aquatic animals, most toxic for fish Residue levels peak in fish within 7days to 2 weeks - rainbow trout LC50 =1ppb in 48hrs. - Striped bass LC50= 0.10 ppb in 96hrs. Inhibited spermatogenesis, deformed intestinal cells, degradation of testes Decrease in growth, egg production, oxygen consumption, red blood cell count Neurotoxicity: convulsions, decreases neurotransmitter levels, prevents binding Behavioral changes in fish

Mode of Action Metablized by both hydrolysis and oxidation Diol metabolite by chemical hydrolysis (pH influenced) Sulfate metabolite by oxidation(P450Prevents GABA from opening chloride channels for hyperpolarization Inhibits Na, K and Mg dependent ATPase in brain. Causes changes in Na and K levels, decreases in Ca and Mg levels in brain Results in repetitive nerve discharges

Detoxification Organisms can increase growth rates to reduce the amount of substance in the body Excretion: mostly in feces, small amounts in urine Filtration of water Bacterial microorganisms Selenium treatment (Kumar et. al, 2007)

References Brown, A.W.A Ecology of Pesticides. John Wiley and Sons: New York. Department of Health and Human Services: Agency for Toxic Substances and Disease Registryhttp:// Edwards, C.A. Ed Environmental pollution by pesticides. Plenum Press. London and New York. Kullman, S.W. and F. Matsumara Metabolic pathways Utilized by Phaenerochaete chrysosporium for degradation of the cyclodiene pesticide endosulfan. Applied and Environmental Microbiology, Kumar, M., C. V. Lakshimi and S. Khanna Biodegradation and bioremediation of endosulfan contaminated soil. Bioresource Technology 99 (2008): Navqi, S. M. and C. Vaishonavi. Bioaccumulative potential and toxicity of endosulfan insecticide to non-target animals. Rehman, S Endosulfan toxicity and its reduction by selenium: a behavorial, hematological and peroxidative stress evaluation. Internet Journal of Toxicology 3 (1). United States Geological Survey. Pesticides in Stream Sediment and aquatic biota: current understanding of distribution and major influences. United States Geological Survey Fact Sheet. Wade, M.G., D. Desaulniers, K. Leingartner and W. G. Foster Interactions between endosulfan and dieldrin on estrogen-mediated processes in vitro and in vivo. Reproductive Technology 11, (6): Yuquan, L., K. Morimoto, T. Takeshita, T. Takekeuchi and T. Saito Genotoxic effects of α- endosulfan and β-endosulfan on human HepG2 cells. Environmental Health Perspectives, 106 (6):