Can Analytical Methods Predict Bioavailability?

The development of methods for the measurement of hydrophobic organic contaminant bioavailability, which perhaps mimic microbial interactions with soil-associated compounds, is gaining interest. In general terms, contaminant bioavailability in soil is controlled by the physico-chemical properties of the contaminant, its source and total concentration, and the physico-chemical properties of the soil, plus, of course, the activity of soil biota. Furthermore, the degree to which a contaminant is determined to be bioavailable may be dependant upon the desired temporal endpoint. Current methods for assessing the bioavailability of contaminants rely on the use of rigorous extractions to remove essentially the entire ‘extractable ’ fraction of the chemical(s) from soil. These 'exhaustive ' protocols are generally considered to offer quantitative recovery and the stringency required for standardizing analytical protocol. The potential of overestimation of the bioavailability of organic contaminants in soil may make harsh solvent extraction protocols inappropriate for the prediction of these