Bioaccessibility of lead in sand intended for playground sandboxes in Slovenia: a preliminary study / Biološka dostopnost svinca v mivki, ki je namenjen otroškim peskovnikom v Sloveniji

Abstract

Slovene press has recently expressed concern for the health of children who ingest playground sand contaminated with lead. However, current assessments may be overestimating the health risk, as they assume that human body absorbs the whole amount of a contaminant. The aim of our study was to see how much lead in sand intended for playground sandboxes in Slovenia really is absorbed and what health risk it may present. To do that, we ran bioaccessibility tests to simulate metabolism and see how digestion affects lead levels. Our results show low bioaccessibility of lead from sand (0.01-36.84 %). Taking into account lead bioaccessibility, we ran several scenarios of sand ingestion in children and established that in general the risk is negligible, except for pica behaviour with extremely high (20 g) ingestion of sand with highly mobilised lead (2.69 µg g -1 ). Further research should assess real-life exposure to lead from playground sand in children and perhaps update these preliminary bioaccessibility data.KEY WORDS: exposure scenarios; intake; in vitro model; risk assessment; toxic metal Fink R, Kukec A, Eržen I. Bioaccessibility of lead in sand intended for playground sandboxes in Slovenia: a preliminary study Arh Hig Rada Toksikol 2015;66:309-314 Children playing in sandboxes often expose themselves to lead in the sand (1-8). In small children this exposure is the highest through unintentional or intentional ingestion (the so called pica behaviour) (9). On average, children can ingest between 50 and 200 mg of sand per day. In case of pica behaviour, ingestion soars to between 1 and 20 g per day (10-12).However, not all of the ingested toxic metal content will be absorbed by the human body. Absorption will depend on age, stomach content, chemical compound containing the metal, and its bioaccessibility (13). In simple terms, bioaccessibility is the absorption potential -that fraction of a substance that is dissociated from soil (or sand for that matter) by gastrointestinal juices and available for absorption. An even more accurate parameter of exposure is bioavailability or the potential of a substance to reach circulation. However, determining it requires complex, expensive, and time-consuming in vivo analysis, which raises practical and ethical issues when it comes to humans and animals. Bioaccessibility, in turn, is a much simpler in vitro method generally simulating gastric and small intestinal digestion, which, depending on the specific method used, correlates with bioavailability (14).The primary aim of our study was to analyse lead concentrations in sand intended for playground sandboxes in Slovenia and to assess its bioaccessibility. Our secondary aim was to simulate different scenarios of oral sand intake in children and compare our exposure assessment to current tolerable intake values. METHODSFirst we identified the producers of sand intended for playgrounds; then we assessed lead bioaccessibility in sand samples by simulating metabolism in vitro and analysing the effects of digestion on absorption;...