SOURCES OF SULFATE IN ATMOSPHERIC DEPOSIT S AS REVEALED BY SEASONAL-VARIATIONS OF CHALCOGENS

Atmospheric deposits (wet and dry deposits) were collected in Nagaoka which is located in the center of Niigata Prefecture, Japan, and conce ntrations of chalcogen elements (sulfur, selenium and tellurium) and o ther chemical constituents were measured to investigate the sources of sulfate. Remarkable seasonal variations were observed in concentratio ns which were lower in summer and higher from winter to spring while i n depositions with less in summer and a lot from autumn to winter when precipitation increases. The ratios of Se/nss-S and Te/nss-S also sho wed seasonal variations with higher amounts in winter and lower in sum mer, further, high correlations among these three elements were recogn ized. As was reported, there is the possibility of the use of telluriu m as a tracer of coal and selenium as a coal and oil combustion efflue nt. It is considered that sulfate in atmospheric deposits in Nagaoka i s influenced by fossil fuel combustion effluents including coal in Eas t Asia.