Can we really model the impact of soil metals bioavailability on human or ecological risk?
Conference
·
OSTI ID:191280
- Golder Associates, Denver, CO (United States)
A variety of assays in humans, plants, and animals, as well as in vitro assays, have been developed to estimate the bioavailability of chemicals in soil to exposed receptors. In vivo studies assess actual tissue uptake, or a surrogate measure of uptake such as blood lead or urinary arsenic, under laboratory or field conditions. In vitro assays generally estimate the solubility of the metals under expected conditions in the gut or root zone. These assays have been used to develop numerous models of bioavailability and its effect on risk. However, even validation of models based on in vitro assays using in vivo laboratory studies is complicated by various soil characteristics, gut contents, and, often, non-linear soil desorption and gut or root absorption kinetics. Validation of risk models are further complicated because field estimates of metals uptake are always a combined measure of numerous exposure and absorption variables in addition to potential impacts of altered bioavailability. Data sets of bioavailability studies for lead and arsenic in humans and animals, along with their associated risk models and field validation studies, are provided as examples of the challenges of estimating risk using bioavailability information. Limitations of the bioavailability assays and risk models are discussed. A probabilistic analysis of identified major sources of uncertainty shows how some of the limitations can be overcome to provide improved, if still imperfect, estimates of risk.
- OSTI ID:
- 191280
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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