Microbial contamination in surface water in urban lakes of Hanoi city, Vietnam

Urbanisation and demographic growth are putting pressure on surface water quality in many large cities. Microbial water quality, as determined by the presence of fecal indicator bacteria (FIB) was investigated in 15 urban lakes in the inner city of Hanoi, Vietnam from 2021 to 2023. FIB (total coliforms, TC and Escherichia coli, EC) numbers exceeded the allowed values of the Vietnam technical regulation for surface freshwater QCVN 08-MT:2015/BTNMT in most studied lakes. High domestic sewage discharge from residential areas and surface runoff from surrounding areas were the major sources of lake water pollution. High FIB numbers in these lakes mean that the use of water for market gardening or leisure activities or the consummation of fish and other aquatic products from these lakes may pose a risk to the population. These results provide the base of a dataset on water quality, which is a necessary precursor for any scientifically based management plan.