Mobilisation and bioaccessibility of lead in paint from abandoned boats.

Fragments of leaded paint sampled from abandoned boats have been ground as a composite and added in different quantities to aliquots of clean estuarine sediment in order to examine the mobility and bioaccessibility of Pb. Concentrations of Pb mobilised by sea water increased with increasing quantity of paint present, but the percentage of total Pb mobilised was greatest from paint-free sediment. Lead mobilisation was enhanced in the presence of the protein, bovine serum albumin, a surrogate for the digestive fluids of deposit-feeding invertebrates, but, likewise, the percentage of Pb mobilised was greatest from paint-free sediment. Lower percentage mobility and bioaccessibility in contaminated sediment than in paint-free sediment is attributed to the relatively low solubility and amenability of Pb compounds in the paint matrix. Despite the low mobility of Pb, however, sediment contaminated by as little as 0.2% paint is predicted to result in dissolved concentrations that exceed available water quality standards.