Preliminary Study of Extraction of Heavy Metals in Sediments under pH-controlled Conditions

• Main Authors: Man-Tsung Kao, 高嫚聰
• Other Authors: Hsueh-Yu Lu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/36697567779374077594

碩士 === 國立中正大學 === 應用地球物理研究所 === 102 === Groundwater is one of the major source for supplying daily and agricultural usages in Taiwan; therefore, the groundwater quality is crucial to have considerable effect on public health. Arsenic pollution increases increases the risk of developing diseases and gradually becomes a serious issue in the management of groundwater resources in Taiwan. According to the principal component analysis on the results of BCR extraction procedure, two principal components can be extracted. Factor 1 includes most of the heavy metals except As. It can be explained with the sorption behavior between extraction solution and sediments. Factor 2 is composed of As, Sr and Zn. It could be controlled by the proportion of organic matter in sediments. In addition, an increase trend of arsenic can be observed in the early stage of extraction experiments. However, the extracted arsenic gradually decreased after 5 day extraction and achieved a minimum concentrations on the final (14 day extraction). This could result from the increase of pH during the extraction experiments. The extraction experiments with various concentrations of NaCl were also performed in this study. The results demonstrate that the amount of extracted arsenic is stable when the extraction solution has a lower concentration of NaCl. However, the extracted arsenic dramatically increases if the concentration of NaCl was greater than 5000 ppm.