多氯聯苯在二仁溪魚體及環境介質分佈之關係及生物習性影響之探討

Distribution of polychlorinated biphenyls in fishes and environmental media of Er-Jn River and the influence of biological behavior.

方政于(Cheng-yu Fang)

指導教授 ： 吳先琪

國立臺灣大學/工學院/環境工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01544

摘要

多氯聯苯在環境中流布方向並非依照濃度之梯度，而是根據活性之梯度，唯有正確取得各介質之活性，才能決定多氯聯苯在環境各介質中之暴露途徑。以往研究者多以總量之數據，經由Mackay及Paterson（1981）所提出逸壓平衡模式之概念，進而推求各介質中多氯聯苯逸壓（活性），然推估之逸壓是否為正確，需要進一步求證。故本研究利用SPME之技術，實際測量二仁溪中底泥、水體及魚體之多氯聯苯活性。
研究結果顯示多氯聯苯在二仁溪各介質之傳輸途徑，以底泥中有機質為二仁溪多氯聯苯釋放之來源，底泥釋放至水體，而魚體經由攝食及鰓之平衡，將活性低於本身之食物中多氯聯苯累積於魚體內。各魚種之平均總活性顯然並未完全隨營養階層增加而增加，以底泥中有機質為食物來源之魚種大鱗鮻最大，多氯聯苯活性達0.16（mg/L, PDMS），而以小魚小蝦為食物來源之魚種大眼海鰱最低，多氯聯苯活性為0.01（mg/L, PDMS），僅有大鱗鮻之6％。顯然食物來源為造成活性相異主因。若將魚種依食性分為底棲掠食及上層掠食之魚種，則上層掠食之魚種其體內之活性隨營養階層增加而增加。而底棲掠食之魚種顯然與營養階層無關，推測可能因其停留於河口覓食之時間不同，停留時間越短多氯聯苯累積量也越少。
多氯聯苯有機質對水之平衡分配係數與辛醇對水之平衡分配係數之對數關係，及脂質對水之平衡分配係數與辛醇對水之平衡分配係數之對數關係，皆呈線性之關係。本研究所獲得之平衡係數顯然高於其他研究者之結果，可能係其他研究者以萃取方式分析現地水樣，誤將附著於膠體物質上之多氯聯苯也視為溶解相，而高估了水中多氯聯苯含量。因此低估有機質對水之平衡分配係數與脂質對水之平衡分配係數。
以底泥活性為推估大鱗鮻之多氯聯苯總量時，其多聯苯含量較實測之魚體多氯聯苯含量為低，而低估風險值。以魚體之活性及以底泥之總量由底泥至水分配係數推估之魚體總量相同，故風險值相同。但三者之值皆高於容許致癌風險10-6，可能影響當地居民健康，應考慮底泥之清除。

關鍵字

多氯聯苯 ； 活性 ； 暴露途徑 ； 固相微量萃取 ； 有機質－水平衡分配係數 ； 生物濃縮係數 ； 生物習性

並列摘要

The migration of polychlorinated biphenyls（PCBs）is not driven by the gradient of concentration, but by that of activity. Only by gaining each activity in the environmental phase can we identify the principal exposure pathways. Current researchers estimate PCBs’ fugacity by making use of the conception of the empirical partition coefficient. However, the estimates remain doubtful. The thesis aims to accurately measure the PCBs’ activity in sediment and fish in Er-Jen River with solid phase microextraction （SPME）method.
The research result reveals that the source of PCBs in Er-Jen River is the contaminated sediment. They were released to the water body. Through the equilibration between gills and water body, and food from lower trophic level than themselves, fish accumulate PCBs. The total activity of each fish species does not necessarily increase with the increase of trophic level. Liza macrolepis which feeds on organic matters has the highest level, which amounts to 0.16 mg/L-PDMS, and megalops cyprinids which feeds on shrimps and small fishes have the lowest activity, which is 0.01 mg/L-PDMS. Obviously, the source of food accounts for the difference in activity. According to the feeding type, we can divide fish species into benthic feeders and pelagic feeders. The activity in pelagic feeders increases with the increase of trophic level. However, activity in benthic feeders has nothing to do with the trophic level. The result indicates that the difference was resulted from the duration of staying in the estuarine regions.
Both logBCFL and logKom increase linearly with logKow. However, they are higher than those reported in the literatures. These discrepancies might be resulted form overestimating the concentration in nature water and mistaking PCBs adsorbed in colloidal matters as in aqueous phase. Previous researchers might have underestimated logBCFL and logKom.
Due to the non-equilibrium among activities of fishes, sediment and water, we might underestimate the human risk adopting the activity in sediment. Cancer risk estimated by activity in fish equals that by sediment content. The cancer risks mentioned above are higher than the acceptable risk, 10-6. Fish, finally uptaken by human, may be hazard to local residents. Remediation of contaminated sediment in Er-Jen River should be considered.

並列關鍵字

polychlorinated biphenyls(PCBs) ； activity ； exposure pathway ； solid phase microextraction (SPME) method ； organic-matter-to-water partition coefficient ； bioconcentration coefficient ； biological behavior

參考文獻

王正雄，黃榮輝、洪文宗，2000，台灣河川魚體多氯聯苯之濃度調查研究，行政院環保署環境檢驗所。

Alock, R. E.; Behnisch, P. A.; Jones, K. C.; Hagenmaier, H., 1998. Doxin-like PCBs in the enviromantal-human exposure and significance of sources. Chemosphere. 37, 1457-1472.

Ashley, J. T. F.; Secor, D. H.; Zlokovitz, E.; Wales, S. Q.; Baker, J. E., 2000. Linking habitat use of Hudson River striped bass to accumulation of PCBs. Environ. Sci. Technol. 34, 1023-1029.

Ashley, J. T. F.; Horwitz, R.; Steinbacher, J. C., 2003. A comparison of congeneric PCB patterns in American eels and striped bass from the Hudson and Delaware River estuaries. Mar. Pollut. Bull. 46, 1294-1308.

Baker, J. E.; Eisenreich, S. J.; Johnson, T. C.; Halfman, B .M.,1985. Chlorinated hydrocarbon cycling in the benthic nepheloid layer of Lake Superior. Environ. Sci. Technol. 19, 854-861.