PARENT SESSION
PM27 - PAHs
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P468) Residue-response relationship between PAHs and lysosomal destabilization in eastern oysters (Crassostrea virginica) and toxicokinetics of PAHs.

Hwang, Hyun-Min^*,1,2, Wade, Terry¹, Sericano, Jose¹, ¹ Geochemical and Environmental Research Group, Texas A&M University, College Station, TX, USA² Department of Chemistry, George Mason University, Fairfax, VA, USA

ABSTRACT- Lysosomal destabilization was measured during the uptake and depuration periods and compared to chemical body residue in eastern oysters (Crassostrea virginica) fed with PAH contaminated food to establish residue-response relationship. Critical body residue (CBR), in terms of lysosomal destabilization (at least 50 % of destabilized cells), was found as around 1,100 ng/g for total PAHs, which is much lower than lethal body residue (LBR). CBR obtained from this study was compared to NOAA NS&T Mussel Watch Project data to evaluate the lysosomal destabilization as a screening tool in tiered risk assessment processes. Toxicokinetics of PAHs were used to understand their behavior in the oysters. The accumulation and elimination of PAHs in oysters is likely related to hydrophobicity, lipid solubility, and biotransformation. Comparison of toxicokinetic parameters with membrane-water partition coefficients showed more linear and less variable relationships than that with octanol-water partition coefficients. Based on fugacity ratios, equilibrium was not reached after 25 days of exposure and bioconcentration factors (BCFs) were estimated based on toxicokinetic parameters (uptake and elimination constants). BCFs ranged from 650 to 160,000. For low molecular weight PAHs, elimination half-lives were less than 10 days, while those of high molecular weight PAHs were highly variable and ranged from 4 to 50 days.

Key words: Critical body residue, Lysosomal destabilization, PAHs, Toxicokinetics