Yasumasa Tojo*, Toshihiko Matsuto*, Takayuki Matsuo*, Hirofumi Sakanakura* and Nobutoshi Tanaka*

*Division of Environment and Resources Engineering, Hokkaido University

+ Correspondence should be addressed to Yasumasa Tojo:
(Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628 Japan)

Abstract

Heavy metal concentrations in the soil surrounding two MSW landfill sites were investigated. At Site-A, the proportion of incineration ash disposed of is high, whereas it is low at Site-B. Incineration ash contains various kinds of metallic elements. Calcium, Zinc, Copper, and Sodium are especially highly concentrated in the ash compared with noncontaminated soil. An 0.1N hydrochloric acid extraction procedure was adopted to extract those metallic elements from the soil samples, and the extracted solutions were analyzed by atomic absorption spectrometry. As a result, high concentrations were identified in soil samples obtained from the surroundings of Site-A. The kinds of metallic elements detected in high concentrations were the same elements which the incineration ash contains in quantities. And the direction of declining concentration was exactly parallel with the principal wind direction. It was suspected, therefore, that incineration ash had been dispersed from Site-A. The area where especially high concentrations were detected is almost entirely within 30m of the site. However, concentrations were still slightly high, even at a distance of 100m from the site. Hence, incineration ash must be treated properly when disposing of it in landfilling operations, to prevent the dispersion of heavy metals.

Key words: incineration ash, dispersion, metallic concentration, landfill site