Abstract
Sulfur isotopic ratios (δ34S) of sulfate in atmospheric deposits (wet and dry deposits) and of the possible source materials have been measured in an attempt to investigate the source of sulfate in the atmospheric deposits in Niigata prefecture, Japan. Seasonal variations of the 3 HS values and their relation to chemical composition of the atmospheric deposits are discuss ed taking into account the δ34 values of sulfur originating from seasalt, oil and coal combustion, biogenic activity and volcanic gases. The δ34S values of sulfate show a remarkable seasonal variation along with seasalt contribution in the atmospheric deposits. The δ34Snss values calculated for non-seasalt sulfate in the deposits also show a seasonal variation. The δ34S values of gas exhaust SO2 from main local anthropogenic sources do not entirely ag ree with the δ34Snss values. It is inferred that sulfate in the atmospheric deposits contains sulfur not only from seasalt and local anthropogenic sources but also from some other sources which emit the isotopically heavy sulfur in larger proportions.
