Estimation of dry deposition at Toyama Prefecture from corrosion of various metal test pieces

Abstract

The amount of annual average dry deposition of SO₄^2-, NO₃^-, NH₄⁺, Cl^-, Ca²⁺, Mg²⁺, K⁺, Na⁺ at Toyama Prefecture were estimated to be 3.5∼8.1, 0.42∼4.7, 6.5∼12, 0.38∼1.4, 0.42∼0.85, 0.31∼0.94, 0.23∼0.69, 4.1∼8.4 mmol/m²/year, respectively.
The influence of the Miyake Island volcanic eruption on Toyama Prefecture was detected in the monthly variation of the amount of dry deposition. The amount of dry deposition of nssSO₄^2- in September 2000 reached a maximum value of 23mmol/m²/year.
The amount of dry deposition of Ca²⁺ showed the maximum in spring. This (is/might be) caused by the influence of yellow sand. In this season, the amount of dry deposition of other ions was also more than other seasons. In winter, the amount of dry deposition of nssSO₄^2- and NO₃^- were small. In summer, the amount of dry deposition of Ca²⁺, K⁺, Na⁺, and Mg²⁺ showed a tendency to be slightly low.