A special issue of Journal of Environmental Science and Health edited by DHI and British Geological Survey has now been published on the topic bioaccessibility of soil contaminants based on the work done by European research collaboration group BARGE (BioAccessibility Research Group Europe).
As stated in the foreword: ‘Soil contamination is a major barrier to the redevelopment of many former industrial sites in inner cities. High concentrations of contaminants such as lead, cadmium, arsenic, nickel and polycyclic aromatic hydrocarbons (PAH) are often found at these “brown sites.” Furthermore, naturally occurring high concentrations of elements such as arsenic and cadmium over wide areas may restrict the use of land for both residential and recreational purposes. In the field of human health risk assessment, oral exposure to contaminants is the primary pathway of interest, in particular for small children who may ingest considerable amounts of soil via hand-to-mouth contact and pica behaviour. At present, the risks associated with soil ingestion are mostly estimated based upon the total contaminant content of soils. However, only a fraction of the many contaminants in soil is usually taken up into the human body and it appears that risk estimates based on total concentration of contaminant result in overestimation of the risk. Many sites across Europe will accordingly be falsely classified as contaminated and remediated resulting in excessive costs. A more practical approach to this problem requires access to accepted, robust and economically feasible methods that can account for the difference between the total and the bioavailable soil contaminant concentrations, thereby making risk assessment more accurate but still protective for human health. Bioavailability of soil contaminants is investigated in vivo with experimental animals with the associated high costs and ethical concerns. Recently, efforts have therefore been directed towards developing and validating in vitro test systems that through simulation of the dissolution of soil contaminants in the human gastrointestinal system (the bioaccessibility) can be used to estimate the risk associated with oral exposure to contaminated soils. As for ecosystem bioavailability, reduced human, oral bioavailability and bioaccessibility means reduced toxicity of a contaminated soil’.
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