Assessment of heavy metal bioavailability and human bioaccessibility in soils in the vicinity of a cement plant

Bioaccessibility and bioavailability of heavy metals were evaluated in uncontaminated soils collected in the geographical area of Agenda 21 Laghi around Lake Maggiore (northern Italy). The distance from the cement plant, identified as a potential point source of contamination, did not affect the bioavailability of the metals. The bioaccessible amount of Zn and Pb appeared to be related to the distance from the cement plant. The use of the soil did not significantly influence metal bioaccessibility and bioavailability. A highly significant correlation between bioavailable metals and soil pH was detected, while the bioaccessible fraction resulted significantly related to the total metal content in soil and less to other soil properties. No correlation was detected between bioaccessible and bioavailable fractions. Considering the bioaccessible fraction of heavy metals in soils, no hazards arise from hand-to-mouth ingestion. However, the bioaccessible concentration of lead may be harmful in the case of children with pica behaviour (intentional consumption).