1. ASSESSING SURFACE WATER QUALITY IN TIEN RIVER BELONGING TO TIEN GIANG PROVINCE, VIETNAM

Tóm tắt

The study was conducted to evaluate surface water quality, location, frequency and monitoring indicators of surface water of Tien River, Tien Giang province in 2019. Data were collected from the Department of Natural Resources and Environment of Tien Giang Province at 7 survey locations at 4 times a year and water variables including pH, temperature, dissolved oxygen (DO), total suspended solids (TSS), chemical oxygen demand (COD) and biological oxygen (BOD), ammonium (N-NH₄⁺), nitrite (N-NO₂^-), nitrate (N-NO₃^-), orthophosphate (P-PO₄^3-), total nitrogen (TN), total phosphorus (TP) and coliform. Surface water quality was compared with National technical regulations on surface water quality (QCVN 08-MT:2015/BTNMT, column A1). The main water variables and potential sources of pollution affecting water quality were evaluated using principal component analysis (PCA), while the dense of water monitoring locations was assessed using cluster analysis (CA). The results showed that surface water of Tien River in Tien Giang province was contaminated with TSS, organic matters (low DO, high COD, high BOD), nutrients (TN, TP, P-PO₄^3-) and coliform. Water quality was affected by several sources such as hydrology, residential areas, urban areas, industry, agriculture and fisheries. The PCA results showed that the main parameters affecting surface water were pH, DO, TSS, COD, BOD, N-NO₂^-, N-NO₃^-, P-PO₄^3-, TN, TP, coliform. The overall results suggested that pH, DO, TSS, COD, N-NO₃^-, P-PO₄^3-, TN, TP, coliform should be included in the monitoring program in this river segment. CA results revealed that from 7 current monitoring locations can be reduced to 4 locations and 4 monitoring periods into 2 - 3 monitoring periods still ensuring the representativeness of water quality on Tien River in Tien Giang province. The research results provide important information to support surface water monitoring on the Tien River.