PARENT SESSION
TA7 - Soil Toxicology and Risk Assessment
Chair: Efroymson , Rebecca1, 1 Oak Ridge National Laboratory, Oak Ridge, TN
Co-chair: Sample, Bradley2, 2 CH2M Hill/Sacramento, Sacramento, CA
8:00 AM to 12:00 PM - Tuesday, 19 November 2002
Room Ballroom A
(386) Bioaccumulation and Prediction of PAH Uptake By Earthworms in Industrial Soils.
Kreitinger, Joseph*,1, Hawthorne, Steven2, Grabanski, Carol2, Miller, David2, Alexander, Martin1, 1 Cornell University, Ithaca, NY, USA2 University of North Dakota, Grand Forks, ND
ABSTRACT- Few studies have been conducted of the bioavailability polycyclic aromatic hydrocarbons (PAHs) in industrial soils and standardized methods do not exist for predicting the bioaccumulation of PAHs in such soils by invertebrates. The objective of this research was to evaluate the biota-soil accumulation factors (BSAFs) for worms in industrial soils and to develop a model for predicting PAH levels these organisms. The uptake of PAHs by the earthworm Eisenia fetida was determined in 15 industrial soils collected from eight manufactured-gas plant sites with a wide range in soot-like anthropogenic carbon (0.3-73%) as determined by thermogravimetric analysis (TGA). The BSAF values for individual PAHs in 14-day bioassays ranged from <0.01 to 0.45 and corresponded to BSAF values determined for field-collected worms. The uptake of PAHs by worms was predicted using equilibrium partitioning theory with and without an adjustment for the rapidly available PAH fraction determined by mild supercritical fluid carbon dioxide (SFE) extraction. Improvements in the prediction of PAH concentrations in worms were marked for some soils. Predictions of PAH uptake by worms were improved using a series of nonlinear models that included a term for the SFE rapidly available fraction, a measure of organic matter quality (i.e. molar C:H ratio or labile:resistant carbon ratio determined by TGA or chemical oxidation) and a term for the physical/chemical properties of PAHs. The R-square value for the best nonlinear model using SFE extractions as a measure of PAH availability was 0.82 and 0.76 for soils collected from coal gas and oil gas sites, respectively. These models were able to predict the concentration of individual PAHs in worms within an order-of-magnitude over a 5 order-of-magnitude range in tissue concentration, 4 order-of-magnitude range in soil PAH concentration and a wide range in soil organic carbon content.
Key words: bioavailability, polynuclear aromatic hydrocarbons, bioaccumulation, worms