Heavy-metal pollution of roadside soils and dusts caused by overuse in an alpine tourist area and an analysis of the pollution behavior

The levels and behaviors of heavy metal pollution caused by automobiles accompanied by "overuse" were investigated in Kamikochi, Chubu Sangaku National Park, Japan. The V, Cr, Ni, Cu, Zn, As, Cd, Sb, Hg and Pb concentrations in the roadside soil and dust were generally lower in Kamikochi than Matsumoto City. In the alpine area, however, higher pollution levels were observed at the "bus terminal", "Kama Tunnel" and "Nakanoyu", where a high frequency of stops, start-ups and continuous idling of automobiles was observed. Seasonal changes in the total metal concentrations (especially in Cu, Zn and Sb) corresponding to the amount of traffic were observed; higher in the summer and lower in the winter. At the higher pollution level sites, the values of pH(KCl) also increased. However, the concentrations of simulated-rain-extracted and the exchangeable form and their percentages to each of the total concentration increased there as well, suggesting that heavy metals are in more labile condition. The percentages of exchangeable Ni and simulated-rain-extracted Sb to their total concentrations were significantly (p < 0.05, multiple regression) related with Eh, pH(KCl), CEC, Org-C, grain size composition and total concentration of the metal. The amounts of dissolution during the survey (1998 similar to 2001) were 269 mug for Ni and 198 mg for Sb per 1 g DW sample at the bus terminal.