PM05 Bioaccumulation and Kinetics of POPs
Exhibit Hall
8:00 AM - Monday
(PM041) Comparing PAH bioavailability in lab-based biomimetic assays vs. bioaccumulation: how reliable are our predictive tools?
Ahrens, M1, Depree, C1, Golding, L1, 1 National Institute of Water and Atmospheric Research (NIWA), Hamilton, New Zealand
ABSTRACT- The sediments of many urbanized or industrialized estuaries are contaminated with PAHs. Yet, often it is not well known to what extent these PAHs are available for uptake by deposit-feeding animals. The objective of this study was to compare PAH bioaccumulation in field-collected invertebrates to estimates of PAH bioavailability using laboratory-based, biomimetic extractions. We collected sediments and resident deposit-feeding macrofauna from a number of urbanized estuaries in New Zealand. Bioaccumulation was determined as the biota to sediment accumulation factor (BSAF), by relating lipid-normalized PAH concentrations in an organism′s tissue to bulk organic-carbon normalized PAH concentrations in the sediment. Biological extractability was estimated using two methods; one, by incubating sediments with an excess of Tenax resin for 24h, and the second, by incubating sediments with dilute concentrations of the synthetic surfactant, sodium dodecyl sulfate (SDS), to mimic the surface-activity of gut fluids. BSAF values for PAHs deviated greatly from the theoretical value of one, but correlated with measures of extractability determined using biomimetic techniques. These results confirm the notion that ′desorbability′ from sediments ultimately determines bioavailability of hydrophobic contaminants, and further suggest that variations in bioaccumulation are probably related to differences in sediment organic carbon composition and PAH binding affinity.
Key words: bioavailability, PAH, sediments, biomimetic