Five sampling sites in the Klang Valley, Malaysia, and three in the Lake Michigan region, U.S.A., were selected for this study. The main objective of the Malaysian study was to study the influence of sources and meteorological factors on the spatial and temporal distributions of local atmospheric cadmium, while the Lake Michigan study was designed to focus on both local and transported atmospheric cadmium in the context of source-receptor relationships. In both studies the characteristics of different cadmium solubility fractions were also investigated. In the Klang Valley, the UPM suburban site recorded the highest mean atmospheric cadmium concentration of 1.85 ng/m, while the highest mean of 1.24 ng/m was found at Chicago in the Lake Michigan region. As PM 2.5 was measured in the Lake Michigan region as opposed to TSP for the Klang Valley, the comparable cadmium level could be much higher for the Lake Michigan region. In the Malaysian study, a high mean soil cadmium concentration of 1048.2 ng/g, which is more than 10 times the natural cadmium content of topsoil, was also measured at the UPM site. In the Klang Valley, atmospheric stability as influenced by atmospheric pressure and temperature was shown to significantly influence atmospheric cadmium distributions. The short-range transport of cadmium from point sources like power plants was also shown to be highly probable. In the Lake Michigan region, long-range transport from source areas in eastern Missouri and central Illinois was shown to influence the levels of atmospheric cadmium measured at Chicago and South Haven. Cadmium in the water-soluble extraction fraction tend to correlate well with other anthropogenic pollutant species, especially selenium. This indicates the highly anthropogenic nature of the cadmium in this fraction. The results from both study areas indicate that rural locations have higher percentages of water-soluble cadmium, that water and dilute acid-soluble cadmium are generally anthropogenic and less than 2.5 mum in size, and that water-soluble cadmium is most like the product of chemical transformations into nitrate and sulfate species during transport.
موضوع (اسم عام یاعبارت اسمی عام)
موضوع مستند نشده
Environmental science
موضوع مستند نشده
Health and environmental sciences
موضوع مستند نشده
Toxicology
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