二仁溪底泥多氯聯苯污染分佈之研究

Investigation of Polychlorinated Biphenyls Contamination in Erh-Jen River Sediment

為建立二仁溪底泥多氯聯苯污染之環境復育策略，本研究採集南台灣二仁溪下游南萣橋流域之6處底泥，採集深度分別為0~30公分（表層底泥）及30~60公分（深層底泥），並針對此兩層不同深度之底泥進行多氯聯苯含量的分析調查，A地點表層底泥之多氯聯苯總合濃度為1.536ppm，其中以2363'4'-CBp (15.62%)佔的百分比最多，A地點深層底泥全部多氯聯苯濃度總合為0.565ppm，其中以23452'3'4'-CBp (45.64%)佔的百分比最多。至於B、C兩地點，所有表層底泥及深層底泥中並未發現多氯聯苯之污染。D點表層底泥之總濃度高於深層，其中以253'5'-CBp (11.63%)所佔百分比最高，深層底泥則以23452'3'4'-CBp (33.14%)所佔百分比最高，其次是242'5'-CBp (14.71%)。E點表層底泥之多氯聯苯污染並不顯著(0.455ppm)，但E點深層底泥則具所有受測底泥中最高濃度的污染(2.718ppm)，其中以252'-CBp (15.44%)與253'5'-CBp (11.99%)含量最高，F點之狀況與E點類似，同樣表層底泥之污染不明顯(0.564ppm)，但深層底泥濃度明顯偏高(1.802ppm)，此層底泥則以252'-CBp,2362'5'-CBp與23452'3'4'-CBp所佔百分比最高。分析各土層之多氯聯苯分佈情形，大部分底泥之同類物種類與商品化多氯聯苯Aroclor1242近似，顯示二仁溪底泥之多氯聯苯污染源主要來自Aroclor1242。此外，本研究結果與先前研究比照分析下，明顯發現多氯聯苯污染有向下游移動的現象，因此未來二仁溪之污染調查與環境復育規劃區域有必要向出海口擴大延伸。

For the purpose to establish the environmental remediation of polychlorinated biphenyls polluted Erh-Jen River in Southern Taiwan, the investigation of PCBs contamination has proceeded. Two layers (the upper layer 0~30cm, and the lower layer 30~60cm, in depth) of sediments from 6 different sites were collected and analyzed. The results showed that in the upper layer of Site A, total PCBs concentration was 1.536ppm, and 2363'4'-chlorobiphenyl (2363'4'-CBp) was the most abundant congeners with a ratio of 15.62%. In site B and site C, there was no significant PCBs contamination. In Site D upper layer, 253'5'-CBp was the major congeners (11.63%) and in the lower layer was 23452'3'4'-CBp (33.14%). The upper layer of Site E is only slightly contaminated (0.455ppm) but the lower layer was the most polluted one (2.718ppm) in all sediments. Analogous to Site E, Site F had a less polluted upper layer (0.564ppm) and a heavier lower layer (1.802ppm ), and the distribution of PCB congeners were similar too. In total 6 sites, most of the layers with significant PCBs contamination showed the similar congener distribution with Aroclor 1242, and some showed the mixed contamination of both Aroclor 1242 and Aroclor 1254. Comparing to previous studies, PCBs was found moving downstream and heading toward the sea in recent years. Therefore, for the further investigation and remediation of PCBs contamination in Erh-Jen River sediment, it is necessary to expand the researching area to the estuarine and the near seashore