Contamination status of surface water from urban rivers and lakes in Hanoi, Vietnam: Pollution parameters and concentrations of selected elements

Abstract

Introduction: Surface water contamination is a concern in urban areas of emerging and developing countries. However, comprehensive and updated studies on the pollution status of urban rivers and lakes in Vietnam are still relatively scarce. Methods: In this study, surface water samples were collected from 5 rivers and 5 lakes in Hanoi, the capital city of Vietnam, to determine some basic pollution parameters (i.e., pH, electrical conductivity–EC, total dissolved solids–TDS, and total suspended solids–TSS) and concentrations of 15 elements. Concentrations of elements were measured by using the inductively coupled plasma-mass spectrometry (ICP-MS) method. Statistical analysis was performed to elucidate potential relationships between pollutants and samples. Results: The pH values in lake water were higher than in river water. The differences in EC, TDS, TSS, and total element concentrations between the lake and river samples were not statistically significant. Concentrations of many elements like Fe, Zn, Pb, Cu, Ni, Cr, and Sb were lower than threshold values specified by the National Technical Regulation on Surface Water Quality. However, concentrations of As and Hg can approach or even exceed the acceptable limits in some locations. Significant correlations were found between some elements and basic parameters. Conclusions: The surface water of rivers and lakes in Hanoi urban areas has been contaminated at low to moderate levels in terms of pH, TSS, and some toxic elements. Further comprehensive monitoring studies should be conducted to characterize the pollution status and ecological impacts of inorganic and organic toxicants in the Vietnamese aquatic environment.