9:45 AM - 10:00 AM
[HTT18-04] Sulfur isotopic compositions of sulfate in rainwater in the Kyoto-Osaka-Kobe area
Keywords:sulfur isotope, rainwater, non sea salt sulfate
We calculated the non-sea-salt (nss) SO42- and nss-δ34S in monthly rainwater samples on a Na basis. The nss-δ34S were slightly lower than the δ34S in monthly rainwater, indicating the effect of sea-salt on atmospheric deposition are small in the Kyoto-Osaka-Kobe area.
The nssδ34S of monthly rainwater samples showed seasonal variation. The monthly rainwater samples in summer had the lower nss-δ34S, suggesting nssSO42- in atmospheric deposition contained sulfur derived from oil in industrial activities. On the other hand, the nss-δ34S and nss-SO42- deposition in the monthly rainwater samples in winter and spring showed higher than those in summer. These results suggest that the addition of coal from the eastern Asia to nssSO42- in atmospheric deposition were occurred in winter and spring.
Sulfur isotopic compositions of monthly rainwater samples varied depending on seasons and sites, indicating they are useful tracer to study on the provenance of sulfur in atmosphere of urban area.