Chemical composition of atmospheric wet depositions from the Yellow Sea and East China Sea

Acid rain can be a serious environmental problem, both for mainland and coastal regions. There are limited studies concerned with the impact of acid rain on coastal waters, with just a single study of this topic in the Yellow Sea and another for the East China Sea. In the present study, we established sampling sites upon Qianliyan Island within the Yellow Sea and upon the Shengsi Archipelago in the East China Sea. During the sampling campaigns, 151 rainwater samples were collected and analyzed for major soluble species at the two sites. The results show that Cl^- and Na⁺ are the major components within the samples, accounting for 55-60% of the total concentrations, with lesser components each comprising 1-11% of total concentrations. Considering pH∼ 5 as the threshold for recognizing acid rain, the two stations were both affected by frequent acid rains, with a frequency of 65% at Shengsi and 40% at Qianliyan. A statistic analysis of the data shows that chemical species with the same or similar sources (e.g., Cl^- and Na⁺) are strongly correlated in terms of rainwater chemistry.