IP02 Wildlife Toxicology
Room 13A/B, Level 4
8:00 AM - 12:00 PM, Wednesday, 12 November 2003
Chair: Forsythe, Barry ,
(IP13) Lipid-normalized levels of organochlorine pesticides in piscivorous birds vary among tissues.
Lowe, E1, Conrow, R1, Schell, J2, Coveney, M1, Marzolf, E1, Richter, S1, Gross, T3, Sepulveda, M3, 1 St. Johns River Water Management District, Palatka, FL, USA2 BBL Sciences, Tallahassee, FL, USA3 USGS, Gainesville, FL, USA
ABSTRACT- During 1998-99, hundreds of birds died on flooded farm fields adjacent to Lake Apopka, Florida. Organochlorine toxicosis appeared to be a primary factor in the deaths of many birds. Chemical analyses of 60 birds which died on site showed that lipid-normalized concentrations of organchlorine pesticides (OCPs) varied widely among tissues. Mean concentrations of toxaphene were 247 mg/kg lipid in the brain, 2084 mg/kg lipid in the liver, and 2984 mg/kg lipid in the fat. Similar inter-tissue variation occurred in several species. For example, a white pelican had toxaphene concentrations of 260 mg/kg lipid in the brain, 1082 mg/kg lipid in the liver, and 3667 mg/kg lipid in the fat. A great blue heron had toxaphene concentrations of 313 mg/kg lipid in the brain, 2833 mg/kg lipid in the liver, and 4783 mg/kg lipid in the fat. Inter-tissue differences also occurred for dieldrin and for DDT and its metabolites. Captive great egrets fed fish contaminated with OCPs also showed wide variation in lipid-normalized tissue concentrations. In these birds, the lipid-normalized concentration of toxaphene in the brain was, on average, about 17 times lower than the level in abdominal fat and about 7 times lower than the level in liver tissue. A simple fugacity model would not predict the observed inter-tissue variation in lipid-normalized concentrations. Further, the low concentrations in brain tissue relative to fat suggest that food deprivation could dramatically alter the pharmacological effects of body burdens of OCPs.
Key words: tissue pesticide concentrations, lake apopka, organochlorine pesticides, birds