EPA Grant Number: R827015-01-0
Title: Passive Sampling Devices (PSDs) for Bioavailability Screening of
Soils Containing Petrochemicals
Investigators: Roman Lanno, Kathleen Duncan
Institutions: Oklahoma State University, University of Tulsa
EPA Project Officer: Bala Krishnan
Project Period: February 1, 1999 to January 31, 2000 (N/C Ext. to June 3
0, 2000)
Project Amount: $135,687
Research Category: Ecorisk analysis
Although total petrochemical levels in different soils may be similar on a chemical basis, biological responses may vary over 100-fold due to differing physical and chemical characteristics of the soil that affect chemical bioavailability. For example, organic matter content differs among soils and will sorb nonpolar compounds, reducing their bioavailabilty to soil organisms. This project examines the issue of bioavailability of hydrocarbons in soils. Due to the partitioning behavior of hydrocarbons in soil, total hydrocarbon measures (e.g., TPH) overestimate the amount of hydrocarbon that is actually available for degradation by microbes during bioremediation or for toxic action on soil-dwelling organisms. The bioavailability of chemicals in soils can be estimated indirectly by measuring toxicity to soil invertebrates or microbial activity, or directly by measuring the amount of chemical present in soil organisms. The objective of this study is to correlate various chemical measures of hydrocarbon availability in soil (e.g., TPH, semi-permeable membrane device uptake, solid-phase microextraction measures) with biological measures of bioavailability (e.g., microbial activity, types of microbes present, earthworm toxicity and bioaccumulation). These measurements will be conducted in the field at sites at the Tallgrass Prairie Preserve, Pawhuska, OK. Sites here have been subject to oil spills in Feb. 1999 and 1991, providing a dramatic gradient in total hydrocarbon. The ultimate goal of this research is to develop sensitive chemical measures of hydrocarbon bioavailability that are well correlated with and can reduce reliance on the more expensive and time-consuming biological measures of bioavailability.