Exposure Pathway in Estuarine Ecosystems (1) – Baseline information investigation and Conceptual model development
Date Issued
2003-07-31
Date
2003-07-31
Author(s)
Wu, Shian-Chee
DOI
912211E002029
Abstract
The distribution of the concentration of PCBs in sediments and fishes of eleven sampling sites
along the ErJen estuary were investigated. The sediment properties of this tropical estuary near a
former PCB contamination hot spot were also investigated before and after wet season to evaluate
the effects of storm events on the seasonal variation of them and the distribution pattern of PCBs.
The results revealed that the averaged PCB concentration decreased from 17.3 to 12.6 ng/g and the
organic content of sediments decreased from 1.5 to 1.0 % after the wet season. The strong
correlation (r = 0.87) between the organic matter content and the PCB content observed before
precipitation was disappeared after the rainy season (r = 0.54). The pattern of PCB concentration in
the sediments in river mouth reflected the influences of surface runoff brought by high precipitation.
The concentration of the light PCBs increased while the heavy PCBs decreased after precipitation in
the sediment at the river mouth. Topsoil in the catchment with relatively higher concentration of
light PCBs was proposed to contribute to the change of the PCB pattern in the sediments downward
the combined sewer outlet. Comparison between the patterns of PCBs in the fishes and in the
sediments within the estuary revealed that surface sediments are the stable food sources of these
bottom feeders. Preliminary study on the exposure route of the bottom feeder, mullet, demonstrated a
strong trophic relationship between sediments and fishes. Relatively similar fingerprints of PCBs in
fishes and in sediments support the hypothesis of the sediment-to-fish exposure route suggested
above.
Subjects
PCBs
estuary
fish
sediments
exposure route
seasonal variation
Publisher
臺北市：國立臺灣大學環境工程學研究所
Type
report
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