Atmospheric Arsenic Deposition in Chiayi County in Southern Taiwan

Abstract

Although arsenic contamination of underground water in southern Taiwan is well known, few studies examine atmospheric arsenic deposition in this area, which might be the major source of such pollution to the soil, water, and even underground water. This research focused on the atmospheric arsenic concentration, dry and wet depositions, and the As distribution around Chiayi County, located in the south of Taiwan. Eight sampling sites are used, both upwind and downwind of an area with heavy industrial and human activities. All samples were collected by a PS-1 high volume sampler at each site, pretreated by a digestion process, and further analyzed with an ICP-MS. The results show that the arsenic deposition flux ranged from 65.0 to 473 μg/m 2 -month in Chiayi County. This deposition flux has no significant seasonal variation, based on the multiple trend results obtained from pooling the dry and wet deposition data. The average dry deposition flux of As ranged from 34 to 161 μg/m 2 -month during the sampling year, and had the opposite trend to the wind speed. Additionally, the correlations between atmospheric arsenic concentration and PM levels were significant, supported by the low p-value (< 0.01) at a 99% confidence level. Meanwhile, the highly linear correlation between As and PM concentrations was also evaluated. The amount of precipitation was statistically correlated to the wet deposition flux (11.3-414 μg/m 2 -month with a p-value = 2 × 10 -7 and r-value = 0.9306. Furthermore, the composition of the As mass concentrations in ambient air were dominated by As (V) in both fall (66.4%) and winter (68.9%). According to the GIS spatial analysis of the As concentration in the dry season, from October to March, the As contribution of local emissions were not significant. Consequently, this study indicates that the atmospheric As around Chiayi County might be sourced from the upwind northern area, and mainly deposited through wet scavenging.

Atmospheric Arsenic Deposition in the Pearl River Delta Region, South China: Influencing Factors and Speciation

“…The majority of the annual As deposition at both sites was contributed to by wet deposition (GZ: 78.85%, DH: 84.05%). The percentages were significantly higher than the results studied in Chialy, South Taiwan, 48 North China, 51 and the cities across Japan. 49,53 Moreover, dry deposition is even found to be the more important mechanism in North China 51 and most cities in Japan.…”

“…No significant difference ( p > 0.05) was observed between two sites. In comparison with other studies around the world, the total deposition fluxes in the present study were extraordinarily higher than those reported in the US, Europe, and Australia and comparable to the Yangtze River Delta (YRD) region, Taiwan, and Japan; whereas, they were lower than the Shanxi Basin, the largest coal basin in China, as well as the Beijing-Tianjin-Hebei region in China, where it is one of the regions with the highest atmospheric As concentration around the world , (SI Table S2).…”

“…51 In Chialy, South Taiwan, precipitation also plays an important role in the relative differences between wet and dry deposition, and the wet deposition contributions (6.9−47.1%) in relatively dry months ( with precipitation more than 100 mm). 48 Similarly, the annual wet deposition contributions in Noshiro, Akita (1713 mm), Matsuura, Nagasaki (1960 mm), and Kashima, Ishikawa (2157 mm) were much higher than other cities with less precipitation throughout Japan. 53 In the present study, although wet deposition played the dominating role in both wet and dry seasons throughout the study period, its average contributed percentages were significantly lower in 03/2015, 04/2015, 11/ 2015, and 02/2016 (GZ: 49.73%, DH: 64.72%), compared with other months with more precipitation (GZ: 86.08%, DH: 81.31%).…”

Arsenic profile distribution of the wetland argialbolls in the Sanjiang plain of northeastern China

“…In the rural area of China, the average As content in the atmosphere was 47.66 mg kg −1 , while the dry deposition flux of As was 1.7 mg m −2 a −1 16 . The average atmospheric dry and wet deposition fluxes of As ranged from 0.41 to 1.93 mg m −2 a −1 and 0.14 to 4.97 mg m −2 a −1 in the Chiayi County in Southern Taiwan, respectively 17 . A previous study showed that anthropogenic As from atmospheric deposition led to a greater accumulation of As in the O horizons of Haplocryod and Cryorthent in northern Sweden 8 .…”

An Improved Method for Monitoring Fine Particulate Matter Mass Concentrations via Satellite Remote Sensing

“…However, due to disagreements in correlation coefficients in various regions, it was inferred that other factors such as aerosol vertical structure, humidification, spatial and temporal states, and meteorological conditions have effects on AOD-PM relationship (Chu et al, 2003;Wang, 2003;Paciorek and Liu, 2010). Based on this, complex statistical methods, such as mixed effect models, general additives models (GAM), Bayesian hierarchical models and geographically weighted regression (GWR), together with ground or model based ancillary data, have been used to study AOD-PM (Liu et al, 2009;Tian and Chen, 2010;Lee et al, 2011;Lin et al, 2013). The feasibility of these complex models, generally require more ancillary data, has not been validated, especially in developing countries (Liu, 2013).…”