• Bioavailability of lead from Dutch made grounds : A validation study

      van Kesteren PCE; Walraven N; Schuurman T; Dekker R; Havenaar R; Maathuis A; Bouwmeester H; Kramer E; Hoogenboom R; Slob W; van Eijkeren JCH; Brandon EFA; Boom G; Miermans K; Piso S; Cave M; Schwillens P; Lijzen JPA; Bakker MI; NAT ; VVH ; SMG ; PRS ; DDB ; CPV; M&V ; V&Z ; BDV (Rijksinstituut voor Volksgezondheid en Milieu RIVMGeoconnectASGTNO ZeistRIKILTBritish Geological Survey, 2014-07-03)
      The soils of historical inner cities in the Netherlands (made grounds) are often contaminated with lead as result of their formation by dumped trash and debris from industrial activities in the past. Children are particularly susceptible to the adverse effects of lead ingestion; a high exposure to lead can affect brain development. Several in vitro laboratory models exist which can estimate the amount of lead released from the soil and able to enter a child's blood (bioavailability). The RIVM has examined the predictability of three of these models. All models have their strengths and limitations, but the so-called Unified BARGE model appears to be the best applicable model for estimating the bioavailability of lead in made grounds. The bioavailibility of lead in six soils was estimated using the three models and the results were compared with the results of a bioavailability study conducted on juvenile swine. The behavior of lead in the gastrointestinal tract of swine was comparable to that in children. Both the Unified BARGE model and the Tiny-TIM model show the same pattern as the results of the animal experiments. However, the Tiny-TIM values underestimate the true bioavailability. The IVD model is only suitable after a correction for calcium content of the soil. An alternative, relatively simple method is to estimate the bioavailable lead in a soil using an extraction with diluted nitric acid. This method can be used as a screening method to estimate the bioavailability of lead in the soil. From the results of the swine study, a standard value can be derived for the bioavailability of lead in made grounds. Policy makers can use this value as a benchmark to determine which fraction of the lead is bioavailable for uptake in the human body. Consequently, by combining the total lead content in the soil and the standard value, it can be determined whether there is a health risk and whether measures should be taken. The use of this standard value renders experiments with laboratory models redundant, thus saving time and money. The outcome of this study indicates that more lead is bioavailable than previously assumed. This may be a reason to re-evaluate the criteria for lead in soils.