Heavy metal transport at a contaminated glassworks site in southeast Sweden.

Heavy metal transport at a contaminated glassworks site in southeast Sweden. In the “Kingdom of crystal” in southeastern Sweden there are a large number of glassworks sites, which are characterized by high pollution levels of a number of metal contaminants. At Pukeberg glassworks site, which is the focus of this study, As, Ba, Cd, Pb, Sb and Zn are present in significantly elevated levels. For this study, which aim is to characterize the release of metals from the glass waste into soil water and groundwater, 54 soil samples from both saturated and unsaturated zone were gathered. Soil water were sampled from lysimeters installed on the landfill area and groundwater were collected from sampling tubes located upstream, at and downstream of the landfill area. The collected samples were analyzed and distribution coefficients (Kd) were calculated as the ratio of the average pseudo-total metal concentrations in soil (from the landfill site with visible glass) to the average dissolved metal concentrations in soil water to describe the leachability of the metal(loid) in the wastes. High concentrations of metal(loid)s were found in soil water samples at the landfill (collected at 30 and 60 cm depth), indicating that metals are leached from the solid waste materials. The distribution coefficients indicate the highest leachability for Ba (Kd= 150 l/kg) and Sb (Kd= 190 l/kg), a moderately leachability for Cd (Kd= 860 l/kg) and Zn (Kd= 500) and the lowest leachability for As and Pb (Kd= 6000 and 16000 respectively). Examining the soil profiles shows that the metal concentrations are considerable lower when there are no visible glass wastes in the soil, which implies that the majority of leached metals are retained in the waste pile. Significant sorption is also suggested by the low concentrations measured in the groundwater samples. The theoretical dilution of the catchment area alone, cannot explain the decrease in metal concentration between the soil water and the groundwater. With exception for Sb, that seems to move relatively unrestrained from the unsaturated zone to the saturated zone. The results indicate that there are sorption processes involved, preventing or slowing down the transport of the investigated metals through the unsaturated zone. The responsible geochemical processes need to be established before assessing remediation strategies for the contaminated area, as it gives information on the factors controlling the metal leaching.