A geochemical case study of Arsenic-tainted paddy soils in Guandu, Taipei, Taiwan

Category Environmetal Geology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Lin, Sheng-Chi۱; Chang, Tsun-Kuo۱; Wang, Ming-Kuang۱; Shyu, Guey-Shin۲; Yao, Pei-Hsuan۱
Holding Date 28 September 2008

According to an official report of paddy soil heavy metals content investigation from Taipei City Government in 2003, soils arsenic content was as high as 160 mg kg-1 at Guandu, Taipei, Taiwan. This study was carried out to examine the intensively distribution of arsenic concentration and try to find out the source of arsenic. Soil samples were collected from 842 hectares for each 1 hectare unit. Arsenic levels of topsoil and subsoil ranged from 4.75 to 458 mg kg-1 and 4.71 to 513 mg kg-1, respectively and there are 143 hectares soil arsenic content ranged from 30 to 60 mg kg-1, and 128 hectares exceeding 60 mg kg-1 at 0-15 cm depth. Irrigation water has concentrations of only up to 26 £gg L-1 As in the study area. Over 61.5 tones of arsenic is estimated from external source in the region, such large amount of arsenic was believed from natural caused more than industrial emission. Finally, the reason was believed at early years the irrigation water mixed with nearby hot spring from Thermal Valley which contain dissolved arsenic and suspended arsenic particles leads to this phenomenon through hundred years.