Concentrations and bioaccessibilities of metals in exterior urban paints.

Paint fragments have been collected from a variety of structures (e.g. walls, lamp posts, doors, railings) from the urban environment of Plymouth, UK, and concentrations of metals determined following acid digestion. Concentrations of most metals were highly variable and spanned several orders of magnitude among the samples (e.g. Pb=4.5 to 36900 μg g(-1); Cr=1.9 to 775 μg g(-1); Zn=39 to 23500 μg g(-1)). The bioaccessibilities of the metals were evaluated using a physiologically based extraction test that simulates the chemical conditions of the human stomach and intestine. The bioaccessibility of a given metal was highly variable among the samples and was greater in the stomach than the intestine in some cases (e.g. Cd, Pb) and greater in the intestine in others (e.g. Co, Cr). Based on total and bioaccessible concentrations in urban paints, Pb remains the metal of greatest concern from a human health perspective.