PH11 Bioaccumulation and Biotransformation of POPs
Exhibit Hall
8:00 AM - Thursday, 13 November 2003
(PH114) Bioaccumulation of organochlorine pesticides in fish and crayfish from soils north of Lake Apopka.
Sepulveda, M1, Coveney, M2, Lowe, E2, Conrow, R2, Marzolf, E2, Marburger, J3, Mace, L2, Ochoa-Acuna, H4, Grosso, J1, Gross, T1, 5, 1 Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA2 St. Johns River Water Management District, Palatka, FL, USA3 National Park Service, Indiana Dunes National Lakeshore, Porter, IN, USA4 Center for Environmental and Human Toxicology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA5 USGS-BRD Center for Aquatic Research Studies, Gainesville, FL, USA
ABSTRACT- During 1998 - 1999, a significant bird mortality event occurred after flooding of a former agricultural property on the north shore of Lake Apopka, Florida (North Shore Restoration Area, NSRA). High organochlorine pesticide (OCP) tissue concentrations from dead birds suggest these compounds may have contributed to the mortality event. The objective of this study was to determine biota sediment accumulation factors (BSAFs) of different OCPs in relation to varying levels of OCP and total organic carbon (TOC) content of soils collected throughout the NSRA. The experiment consisted on exposing biota in 700-L tanks to inundated sediments, with three replicates per treatment. We tested three levels of TOC (low ⩽ 10; medium 25 – 35; and high ≥ 35 %) and four levels of OCPs (based on toxaphene values: controls, below detection limit; low 2.5 ± 0.2; medium 18 ± 2; and high 34 ± 6 mg/kg). Twelve treatments were established, and test organisms (Eastern mosquitofish, Gambusia holbrooki and calico crayfish, Orconectes immunis) were sampled at regular intervals (weeks 0, 2, 4, 8, 12, and 16). Most OCPs reached steady-sate at or after four weeks. OCPs with highest tissue values were DDT and derivatives (range of overall means for mosquitofish and crayfish: 1,260 – 298 ppb); dieldrin (62 – 17 ppb); and toxaphene (1,947 – 336 ppb). Regardless of soil OCP and TOC, BSAFLipidNormalized/TOCNormalizedwere higher in mosquitofish compared to crayfish, reflecting their different trophic levels (overall means and SE for DDT and derivatives, dieldrin, and toxaphene: 5.9 ± 0.9 and 3.3 ± 0.2; 4.8 ± 1.1 and 3.2 ± 0.2; 2.7 ± 0.5 and 1.4 ± 0.2, for mosquitofish and crayfish, respectively). In order to tests for the effects of TOC in bioaccumulation, we eliminated TOC from the above formula and found that biota kept in tanks with low TOC accumulated OCPs at a significantly higher rate. For instance, mosquitofish and crayfish from tanks with low TOC high OCP bioaccumulated 82, 55, and 100 times more DDT and derivatives, dieldrin, and toxaphene, respectively compared to animals from the high TOC high OCP treatment. We conclude that under these microcosm conditions, high TOC values resulted in a decreased bioavailability of OCPs to biota.
Key words: pesticides, BSAF, bioaccumulation, TOC