Arsenic (and other Heavy Metal) Testing and Assessment
Elevated levels of arsenic and other metals and metalloids are a common natural occurrence in some parts of the UK, including the southwest of England.
Where the levels exceed generic assessment criteria (GAC), bioaccessibility testing can be undertaken to assess whether or not the elevated levels are harmful to human health.
The GAC assume that 100% of the contaminant (e.g. arsenic) is taken up by systemic circulation (i.e. 100% bioaccessibility). However, naturally occurring arsenic and other metals and metalloids are commonly not 100% bioaccessible and therefore often less harmful to human health.
In order to provide data for a site-specific risk assessment, bioaccessibility testing using the unified BARGE method (UBM) or physiologically based extraction test (PBET) is undertaken on soil from the site. The UBM and PBET bioaccessibility tests are laboratory tests that simulates conditions in the gastrointestinal tract to assess the human bioaccessibility of potentially harmful elements by ingestion.
The CLEA model software is then used to produce a site-specific assessment criterion (SSAC) for the contaminant (e.g. arsenic) for the proposed land use.