Distribution of polychlorinated biphenyls in fishes and environmental media of Er-Jn River and the influence of biological behavior.
Date Issued
2005
Date
2005
Author(s)
Fang, Cheng-yu
DOI
zh-TW
Abstract
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.
Subjects
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
polychlorinated biphenyls(PCBs)
activity
exposure pathway
solid phase microextraction (SPME) method
organic-matter-to-water partition coefficient
bioconcentration coefficient
biological behavior
SDGs
Type
thesis
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