Attic dust reflects long-term airborne contamination of an industrial area: A case study from Ajka, Hungary

Abstract

Recent research suggests that airborne pollutants, deposited in the urban environment, can be efficiently studied by attic dust analysis. Here, an attic dust study was carried out to determine the long-term airborne contamination load in the industrial town of Ajka, Hungary, by attic dust analysis. The spatial distribution of trace element contamination in airborne attic dust samples was to be mapped in order to relate spatial distribution to potential sources. The sampling strategy followed a grid-based stratified random design and samples were collected in 27 houses in the 64km2 project area. Houses with attics intact for at least 30–40years were chosen to represent long-term industrial pollution. The concentrations of six trace elements (As, Cd, Cu, Ni, Pb and Zn) were measured with ICP-OES, whereas Hg content was analyzed by CV-AAS. Measured concentrations above the environmental standards were encountered. The univariate distribution analysis shows that Pb, Hg, Zn and Cd distribution is dominated by anthropogenic sources, and characterized by high extreme values, such as elevated Hg-concentrations around the lignite-fired power plant. Arsenic and Cu-distributions seem equally influenced by background and anthropogenic processes. Nickel shows lower concentrations and variability, and its major source is the natural geochemical background. To study the geochemical element behavior, a correlation analysis was performed to estimate the metal sorption to Fe-oxy-hydroxide phases. Results show a good spatial correlation of contamination and sources such as lignite mines, lignite-fired power plant and traffic. Attic dust appears to be an efficient and cheap sampling medium to study and map long-term airborne contamination and possibly associated human health risks in an industrial setting.