Recent developments in assessing the bioavailability of persistent organic pollutants in the environment

There is a growing realisation that the total amount of persistent organic pollutants (POPs) present in the soil may not relate directly to environmental risk and hence impact on living organisms including humans. This neglected area of environmental science requires estimation of the bioavailability of POPs to correctly assign environmental risk to them. Procedures have been developed for the selective and sequential extraction of metals from environmental matrices, but no such detailed work has been undertaken for POPs present in soil and related materials. Nevertheless, we have noted some progress, which we review in this article. The three most common approaches that have emerged so far include: (a)the selectivity that can be achieved by careful selection of (organic) solvent in the extraction process; (b)the use of cyclodextrin as a chemical extractant to mimic the bioavailability of POPs; and, finally, (c)the use of simulated gastro-intestinal digestion to mimic the availability of POPs to living organisms. We review each approach using selected examples. It is clear that further work is required to understand the limitations and the advantages of each approach described and to investigate further methods for assessing the bioavailability of POPs from environmental matrices.