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Chen S.-Q.,Anqing Teachers College | Tong F.,Hefei University of Technology | Ma D.-Q.,Anqing Teachers College | Zhou A.-J.,Hefei University of Technology | And 2 more authors.
Wetland Science | Year: 2011

Over the last several decades, the lake environments have received large amounts of pollutants. Among these pollutants, most of the heavy metals (e.g. cadmium, lead, copper, chromium and zinc) may be toxic. Heavy metals are readily mobilized by human activities. Human activities have accelerated cycling and increased metal delivery of weathering products and pollutants to lake environments via the surfaces/waters which can be transported, deposited and buried along with sedimentary dynamics. In July 2009, the current situations of spatial distribution of concentrations of heavy metals including copper, chromium, zinc, cadmium and lead in sediments of Pogang Lake, and the potential ecological risk from the five kinds of heavy metals, were studied by means of Mapinfo thematic map production technology and Lars Hankson index model respectively. The result showed that concentrations of the heavy metals ranged 110 -145 mg/kg, 51.9-68.1 mg/kg, 119-155 mg/kg, 1.05-1.41 mg/kg, and 38.0-62.1 mg/kg dry weight for chromium, copper, zinc, cadmium and lead, respectively. The copper concentration exceeded the threshold of second level standard of the GB15618-1995, the cadmium concentration also exceeded the threshold of second level standard, and the concentrations of other heavy metals were within permissible limits. The spatial distributions of the maximum concentrations of copper and chromium, cadmium and zinc were similar. The highest concentrations of these four kinds of heavy metals occurred at the northeast part of Pogang Lake which is adjacent to Zongyang city, of The copper and chromium, cadmium and zinc showed a synergistic or additional toxicity effect and the harmfulness of these metals would be amplified. The nail factories in Zongyang city possibly export the pollutant water which contains copper and chromium in electroplating process. At the northeast part of Pogang Lake, there are about 3.5 km 2 of paddy fields, the gross weight of cadmium which through the using of the phosphatic fertilizer exporting to this region. The maximum of lead concentration occurred at the western riparian, where the province highway named S228 was wriggling along the lakeside from north to south, so the automobile exhaust was assumed to be the important pollutant source of lead. Ingestion of even trace quantities of cadmium can influence not only the physiology and health of individual organisms but also the demographics, distribution, reproduction, and survival. The Hankson index of cadmium which signified potential ecological risk reaches up to 654.00. Besides, Hankson index also showed that the harmful of the other four heavy metals were slight. So cadmium was the main pollutant in the sediments of Pogang Lake. The cadmium pollution in the sediments led to the highest damages to the ecological system of Pogang Lake.

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