Accessing Heavy Metal And Nutrient Pollution In Sediments And Surface Water In To Lich River, Hanoi, Vietnam
To Lich River, the main river running through Hanoi (Vietnam) residential areas, has been subjected to extreme pollution due to triple population growth in the last 20 years. Nevertheless, there have been few studies addressing its water quality and pollution level. In this research, concentrations of 8 heavy metals (Cr, Ni, Cu, Zn, As, Ag, Cd, and Pb) and several water quality parameters were measured in sediments and surface water in 19 river locations. Geo-accumulation index (Igeo) indicates there is no sediment contamination in terms of Cr, Ni, As and moderate to heavy contamination in terms of Pb, Cu, Zn, Cd, Ag. Besides, all heavy metals show a minor to extremely severe enrichment factor (EF). Top five elements with the highest Igeo and EF are Ag > Cd > Zn > Cu > Pb. It is also found that Cd, Zn, and Cr concentration exceed the Vietnamese sediment standard (QCVN 43:2017/BTNMT). Water quality indices (NH4+, NO3-, NO2-, TSS) and metal concentrations (Cr, Ni, As, Pb, Zn, Cd) also exceed the national standard for surface water (TCVN 5942:1995). Compared with previous studies in 2005, 2006, and 2011, this research shows a general decrease in water heavy metal concentration.