02. Study on water quality according to WQI index on North Hung Hai river, Hung Yen province and influencing factors

Abstract

Water quality of Bac Hung Hai river, Hung Yen province is being affected by activities related to daily life, industry, agriculture, trade and services,... The study conducted a quick assessment of water quality by specifically determining WQI_SI, WQI_3NTS, WQI_4NTS. Then, compare the value of WQI_3NTS or WQI_4NTS with the current scale and get the following results: 16.67 % of samples have WQI = 10 - 25, 16.67 % of samples have WQI = 26 - 50, 50 % of samples with WQI = 51 - 75 and 16.67 % of samples with WQI = 76 - 90, with the following levels: Heavily polluted; Can be used for marine purposes; Irrigation (or equivalent) or water supply after treatment. The research results are also the basis for knowing the factors and trends that affect the WQI value that need to be monitored, specificlly: When the switching from the dry season to the flood season; When a large flow of good quality water is supplied at the sampling points; When the pollutantsare rarely received at the sampling point,…the WQI index to be monitored has a large value and vice versa. Therefore, it is recommended that the government and management levels take appropriate measures to control.