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UDC 628.394(597-25)

Nguyen Dinh Dap, Volshanik V. V., Dzhumagulova N. T.

The study of the ecological state of the To Lich River in Hanoi

Summary

To Lich is a big river in the city of Hanoi, the capital of Vietnam. The river system receives municipal wastewater as well as effluents from 100 industrial enterprises located in five industrial areas in the central part of Hanoi. The To Lich River channel has accumulated about 284 thousand m³ of sediments, 7347 tons of different metals. The total load of nine metals on the river estuary is 161.7 kg/day. The information on the method and results of the field studies of the To Lich water and riverbed pollution with heavy metals is presented. The study was aiming at the assessment of the total load of heavy metals discharged and accumulated in the bottom deposits of separate To Lich River reaches (at the point of effluent discharges) as well as the assessment of the daily intake of organic carbon and heavy metals at the river estuary. To evaluate the general ecological state of the river the analysis of not only the river water quality but also the quality of the sediments was carried out. At that the following parameters were entered: water quality index (WQI) and sediment quality index (SQI) on the basis of seven pollutants: for water –chromium (Cr), nickel (Ni), manganese (Mn), copper (Cu), zinc (Zn), arsenic (As) and lead (Pb); for sediments –Cr, Ni, Cu, Zn and Pb.

Key words

wastewater , heavy metals , drinking water supply , water quality parameters , water supply , water sampling