Oral bioavailability of heavy metals and organic compounds from soil ; too complicated to absorb? An inventarisation of factors affecting bioavailability of environmental contaminants from soil
Biologische beschikbaarheid van zware metalen en organische verbindingen uit grond ; te gecompliceerd om op te nemen? Een inventarisatie van factoren die de biobeschikbaarheid van milieucontaminanten uit grond beinvloeden
26 May 2012, PDF |
36 pages |
Sips AJAM, van Eijkeren JCH
RIVM Report 711701002
Bioavailability plays an important role in risk assessment of environmental contaminants from soil. It is one of the determinants in the assessment of intervention values. In present risk assessment, bioavailability from soil is supposed to be 100% due to a paucity of reliable information. However, when it should appear that in this model bioavailability is overestimated by a factor 2 or more, this would imply that the present intervention values are 50% or more too low. This report gives an overview of the data available on bioavailability of the heavy metals lead (Pb), arsenic (As), cadmium (Cd), and toxic organic compounds like PCDDs/PCDFs and PCBs from soil. Beside background information on these compounds, attention is paid to the issue of defining the concept of 'bioavailability' properly, including methodologies for determining bioavailability and to factors influencing bioavailability. A critical survey of all these items leads to the conclusion that the soil matrix can reduce the bioavailability of environmental contaminants with factors up to 10, compared to administration in a solution. However, scarcity of data hampers straightforward application such as the calculation of levels that would necessitate intervention. To our opinion, future research is required. It should focus on: 1) defining the concept of bioavailability, 2) obtaining information about the extraction process of contaminants from the soil matrix by digestion juices, and on 3) absorption processes out of digestion juices into systemic blood, in which especially attention should be paid to speciation of heavy metals in these juices.
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