PARENT SESSION
PS19 - Bioavailability
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P181) The Use of Tissue BAF Models for Various Plant Types in Risk Assessment.
McCarthy, Christopher*,1, Chartrand, Andrew1, Hilscher, Larry2, 1 CH2M HILL, Houston, TX, USA2 CH2M HILL, Austin, TX
ABSTRACT- Literature-based soil-to-plant bioaccumulation factors (BAFs) and regression models are useful tools in ecological risk assessment for estimating the concentrations to which receptors may be exposed when feeding on plants. The objective of this study was to determine if there are significant differences in BAFs for specific plant types when compared to those developed based on many different types of plants. Using plant and soil concentrations from a former metals foundry site, plant tissue BAFs were calculated for eight metals (As, Cd, Cu, Hg, Pb, Ni, Se, and Zn). Initially, regression models were developed using all site-specific data and were compared to the plant tissue regression models published by Efroymson et al. (2001). Site-specific regression models were then developed for grasses (the predominant vegetation at the site) separately and were also compared to those from Efroymson. BAFs calculated from the grasses in the Efroymson data set were then used to validate the site-specific grass-specific regression models. Regressions developed by using all site-specific data differed from the regressions from Efroymson for all eight metals. Regressions for grasses also differed when compared to regressions from Efroymson . These differences were primarily attributed to varying bioavailability of the metals tested and the moisture content of the plant species. The plant species in the regressions by Efroymson vary greatly but were primarily based upon crops. Using regression models for specific groups of plants to estimate plant tissue concentrations may be more appropriate for use in risk assessment.
Key words: BAFs, plants, metals, ecological risk assessment