Environmental risk analysis and bioaccumulation effect of mercury and dioxin in polluted aquatic environment
Date Issued
2016
Date
2016
Author(s)
Liao, Pei-Yu
Abstract
Mercury and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) accumulate in organisms through food webs and exert potentially toxic effects on aquatic organisms and humans. This study examined the levels of mercury and PCDD/Fs in organisms and sediment samples collected from a saltwater pond at the site, a chloralkali factory that shut down in Tainan City, Taiwan. It was also a pentachlorophenol production plant. After the factories were shut down in the 1980s, mercury and PCDD/Fs contamination remained, posing severe health hazards. The correlation between PCDD/Fs congener accumulation patterns in distinct fish organs and the sediment was evaluated. Mercury and PCDD/Fs levels in all the fish samples exceeded food safety limits, and the concentrations of mercury and PCDD/Fs in each species were closely correlated (n = 12, Spearman’s rank correlation [R] = 0.811, p < 0.01). The mercury concentrations were positively but non-significantly correlated with the weight (n = 11, R = 0.741, p < 0.01) and length (n = 11, R = 0.618, p < 0.05) of the species. The fish likely accumulated the contaminants through ingestion of other organisms or the sediment. However, after the pollutants entered a fish, they exhibited distinct accumulation patterns because of their differing chemical properties. Specifically, the mercury concentration was correlated with organism weight and length, whereas the PCDD/Fs concentration was associated with organ lipid content. In this study, the 1,2,3,4,6,7,8-HpCDF concentration was lowest in the sediment but highest in the organisms. However, the OCDD concentration was highest in the sediment but lowest in the organisms. The dominant congeners 1,2,3,7,8-PeCDF, 1,2,3,4,6,7,8-HpCDF, 1,2,3,6,7,8-HxCDD, and 1,2,3,4,6,7,8-HpCDD in the fish differed from those found in the sediment samples. The study results are valuable for assessing the health risks associated with ingesting mercury- and PCDF/F-contaminated seafood from the study site. Therefore, it is suggested that the public should be alerted through bans and advisories when a threat to human health may occur from the consumption of contaminated fish.
Subjects
Dioxins
Mercury
Biota-to-sediment accumulation factors
risk
Type
thesis
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