| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 87 === This study is dedicated to characterize the polychlorinated biphenyls contamination in sediments from Er-Jen River in Tainan prefecture. The sediment and riverside soil of Er-Jen River in Wan-Li area has been polluted by unhandling waste water and burning scrap metals for a long time. Sediments of five columns were collected by using plastic columns from surface of sediment to a depth 45 cm. Sampling sites were located in the north side of Er-Jen river and ranged from east side of Nan-Din Bridge in every 50 m. After air dried, the soil columns was separated in 5 cm each. The properties, concentration of polychlorinated bphenyls and the distribution of polychlorinated bihenyls congeners of the sediments were then analyzed.
The texture of the sediment of Er-Jen River is silty loam. The content of clay is 9.95% to 20.47%. The pH value is a little different in five columns and ranged from 7.9 to 8.2. The content of organic carbon is 0.37% to 0.97%. The cation exchange capacity(CEC) is 26.70 cmole Kg-1 to 44.34 cmole Kg-1. The heavy metal content in sediments: zinc is 30.24 mg Kg-1 to 137.46 mg Kg-1, lead is 3.06 mg Kg-1 to 79.62 mg Kg-1, iron is 764.3 mg Kg-1 to 1464.31 mg Kg-1, copper is 25.69 mg Kg-1 to 56.42 mg Kg-1, chromium is 0.45 mg Kg-1 to 5.84 mg Kg-1, cadmium is 0.17 mg Kg-1 to 1.17 mg Kg-1 and nickel is 2.73 mg Kg-1 to 22.77 mg Kg-1. The content of sulfate is 42 mg Kg-1 to 370 mg Kg-1 and nitrite is about 0.019 mg Kg-1 to 0.087 mg Kg-1.
The lowest concentration of polychlorinated biphenyls in sampling sediments is D1(0~5 cm, column D) 0.48μg g-1 and the highest is B6(26~30 cm, column B) 4.32μg g-1. The concentration of polychlorinated biphenyls is higher in lower layer of sediments than in upper layer of sediments in all columns, and higher in columns for downstream of river columns than in column for upstream of river. The contamination of polychlorinated biphenyls was found in the sediments even to a depth of 45 centimeter. The distribution of polychlorinated biphenyls congeners is different between upper layer and lower layer of sediments. The polychlorinated biphenyls congeners upper layer sediment is similar to the distribution of Aroclor 1242. But PCB congeners of 24’-CB and 262’-CB in surface were more concentrated than in Aroclor 1242. It indicates that the dechlorination of PCBs occurred in Er-Jen River sediments. The polychlorinated biphenyls congeners in lower layer sediments had the characteristic of Aroclor 1242 and Aroclor 1254, and the product of dechlorination was also found in lower layer of sediment.
|
|---|
