Using bioaccumulation of filter-feeding bivalve Corbicula fluminea to assess the metallic pollution in urban rivers
Date Issued
2015
Date
2015
Author(s)
Feng, Ying-Chieh
Abstract
Global urbanization in recent decades has caused severe pollution impacts to river ecosystems due to excess metal contaminations by various human activities. The filter-feeding bivalve Corbicula fluminea, which is capable of bioaccumulating metallic contaminants, have been increasingly used as biomonitor for the time-integrated toxic impacts of metallic pollution of freshwater ecosystems worldwide. However, limited studies have been done for long-term biomonitoring programs for riverine metallic pollution using C. fluminea as bioindicator in rapid urbanized Asian countries including Taiwan. In this study, We carried out in-situ exposure experiment using caged C. fluminea in two urban rivers in Taiwan including Danshuei River and Datun River from the highly urbanized region of northern Taiwan aiming to (1) evaluate the relationship between metallic concentrations in water and body tissues of C. fluminea after exposure; (2) determine the bioaccumulation extent of different metals in the body tissues after exposure; (3) reveal the potential accumulative pathways of different metals in C. fluminea by comparing their bioaccumulation patterns among different body tissues; (4) confirm if C. fluminea could serve as an appropriate bioindicator for bioaccumulation monitoring the urban rivers in Taiwan. Our results indicated that most metallic contaminants, including Zn, Cu, Ni, Cr, Pb and Cd, could effectively accumulated in the soft tissues of caged C. fluminea during the in-situ exposure in the urban rivers with low to moderately metallic pollution for relatively short period of time (i.e. 21–28 days). Corbicula fluminea had different bioaccumulation tendency for different metallic contaminants. Despite the higher particulate concentrations comparing to the dissolved concentrations were measured for all metals in rivers, C. fluminea demonstrated effective bioaccumulation of dissolved metals than particulate metals. Although there were inter-site differences in the total metallic bioaccumulation capacities of the caged C. fluminea, similar patterns of BAF variation among different body tissues were apparent. The visceral mass was most important type of body tissues showing metallic bioaccumulation suggesting that the contamination pathways was dominated by food uptake. Thus, our findings suggested that C. fluminea served as good biomonitor for the ecotoxicological impacts of most metallic contaminants (e.g. Zn, Cu, Ni, Cr, Pb, and Cd). In particular, C. fluminea could be used as sentinel organisms for Cd contamination in rivers as an early signal for potential ecological risk due to its high sensitivity to Cd contamination. Therefore, we suggested that C. fluminea should be considered as the bioindicator for long-term monitoring of the ecotoxicological impacts of metallic pollution monitoring of urban river environments in Taiwan.
Subjects
metal contaminations
urban river
mussel
bioaccumulation
biomonitoring
Type
thesis
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