Understanding how people are exposed to pollutants in contaminated environments is one of the key issues related to the protection of public health. In this study, metal exposure is characterized for residents around glassworks sites in southeastern Sweden, where arsenic, cadmium and lead in soil at and around the glassworks properties have been measured in concentrations more than 1000 times the Swedish EPA limits. Exposure to the metals in question has been associated with a number of adverse health effects, and previous studies among glass factory workers have shown increased cancer risks, generally ascribed to lead exposure. Ongoing investigations in the Swedish glassworks region indicate that the increased cancer risk applies to local residents too, and not only to glass factory workers. To determine whether metal exposure is a probable key controlling factor for an observed negative effect in a population – such as the increased cancer incidence in the Swedish glassworks region- the total intake via different exposure routes needs to be characterized (via ingestion of local crops and drinking water, inhalation of dust etc.). Here we present some of the major difficulties in assessing exposure and risks for residents living near contaminated sites, where i) exposure may occur through various routes, and ii) the characterization of variables affecting exposure is challenging due to a high temporal and spatial variability.
As an example we focus on exposure through consumption of homegrown vegetables, wild berries and mushrooms and show how it may vary– both for residents in potential exposure areas (in households <500 m from one of 22 different glassworks) and for people in reference households (> 2 km to the nearest glassworks site). Both deterministic and probabilistic assessments were performed, based on metal concentration data for 15 common homegrown crops and wild berries/mushrooms, and data on the consumption of homegrown items. Although metal concentrations were generally higher in the items grown around glassworks sites than in reference areas, the results are not conclusive and the differences are often small, confirming that high total concentrations in soil are not always reflected in the crops grown therein. Lead is the metal where the risk of adverse health effects is considered the lowest. For As and Cd there is a risk of an excess intake via the homegrown vegetables exposure route for some consumers, but this applies to the reference group as well as to residence around contaminated sites.