Study of Ambient Air Particle-Bound As(p) and Hg(p) in Dry Deposition, Total Suspended Particulates (TSP) and Seasonal Variations in Central Taiwan

Abstract

This study investigated the ambient air particle-bound As(p) and Hg(p) levels and compositions in dry deposition and total suspended particulates (TSP) at five sampling sites in Central Taiwan (suburban/coastal, downtown, residential, industrial and wetland) during the years of 2009 and 2010. The main industrial sources of studied metals in various investigated sites include: steel, electronic, plastic, and chemical industries, the Taichung thermal power plant (TTPP), fossil fuel combustion, a science park, transportation, and waste incineration. The samples were digested with hydrochloric acid (HCl) and nitric acid (HNO3), then they were analyzed for metals by ICP-MS. The mean As(p) levels in dry deposition were the highest at Quan-xing site (industrial) and the lowest at Chang-hua site (downtown). Moreover, the mean Hg(p) levels in dry deposition were the highest at Gao-mei site (wetland) and the lowest at He-mei site (residential). In addition, the mean As(p) levels in TSP were the highest at He-mei site (residential) and the lowest at Gao-mei site (wetland). The mean Hg(p) levels in TSP were the highest at Quan-xing site (industrial) and the lowest at Gao-mei site (wetland). Regarding seasonal variation, the lowest levels in dry deposition for both particles As(p) and Hg(p) occurred in spring and summer. Finally, the lowest levels of As(p) and Hg(p) in TSP were observed in fall and winter.