PARENT SESSION
PS20 - Passive Samplers for POPs
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P197) Comparison of Lipid-Containing SPMDs and Oysters ( Crassostrea gigas) for Assessing Organic Chemical Exposure.

Huckins, J^*,1, Prest, H², Petty, J¹, Hodgins, M², Gibson, V¹, Clark, R¹, ¹ USGS, CERC, Columbia, MO, USA² Long Marine Laboratory, University of California, Santa Cruz, CA, USA

ABSTRACT- We performed concurrent, controlled, flow-through exposures of lipid-containing SPMDs and oysters ( Crassostrea gigas) to a range of concentrations of a mixture of PAHs. The results show that SPMDs and oysters concentrate the same compounds, but to different degrees. The thermodynamic capacity of SPMDs (i.e., the total mass of chemical per unit mass of whole SPMD at equilibrium) to accumulate contaminants is greater than that of bivalves (wet or dry weight). This characteristic of SPMDs generally enables integrative sampling, but increases response times (reciprocal of the overall uptake rate constant) to changes in concentrations. Although the SPMD response time is longer than oyster′s, detectable residues from a spike in chemical concentration in the initial phase of an exposure are more likely present in SPMDs than in oysters at the end an exposure. Also, 20-day PAH (log K_ows > 6.0) concentration factors (CFs) in oysters exposed to the low treatment level ranged from about 0.4 to 1.2 orders of magnitude higher than those exposed to the high treatment. This lack of concentration-independence of oyster CFs (i.e., the lack of proportionality to exposure concentrations) appears to be linked to a toxicity-induced cessation of feeding, and has negative ramifications for exposure assessments with bivalves.

Key words: SPMDs, oysters, uptake, comparison