Species fractionation of soil in high arsenic contaminated soil and accumulation of arsenic in the crops

• Main Authors: Hsieh, Chia-Lin, 謝佳霖
• Other Authors: Chen, Ting-Chien
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/72674948878803160894

碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 104 === Arsenic is one of the most toxic substances in the world. It exists with different species due to different characteristic patterns. The species affects the potential solubility and results in different hazards to the environment. The Wenzel sequential extraction procedure is a widely applied method used to assess the hazard extent of heavy metals in the environment. This study collected soil samples from farmlands in Minsyong Township, Chiayi County and Guandu Plain, Taipei, as well as from surrounding soils from the Taipei Ruifang copper smelter wasted-gas tunnels. The soil samples were analyzed for total arsenic concentrations and arsenic patterns were extracted with the Wenzel sequence extraction method. In addition, the total arsenic in the field crops was analyzed in Minsyong field to calculate the transfer and bioaccumulation factors to assess the capacity of arsenic accumulation in crops. The results showed that different regions and different concentrations of total arsenic significantly and positively correlated with the soil properties including Fed, Mnd, Feo, Mno , cation exchange capacity, clay content, and organic matter. Bioaccumulation factors and transfer coefficients for both broccoli and rice were less than 1.0, which suggested the crops had a poor ability to accumulate arsenic. In addition, the transfer coefficients were less than 1.0, which also suggested arsenic had low transmission capacity in various parts of the crops. The percentages of As extracted with the sequential extraction method showed that more than 70% of As was mainly fixed to both amorphous and crystalline Fe/Mn oxides. The non-specific adsorption species, having higher environmental impact, was less than 1% in the Minsyong and Guandu soils but the Ruifang soils averaged s about 10%. The former two soils were collected from paddy fields because of alternating wet and dry processes resulting in As being dissolved to the environment. Keywords: Arsenic, species, sequential extraction procedure, bioaccumulation factors, translocation factor.