VU DUC TOAN AND TA MINH PHUONG
Abstract
This study evaluated the status of source-water quality in key brackish-water shrimp-farming areas of Northern and North Central Vietnam using monitoring data from 2021 to 2025. The study covered 16 sites in five provinces. Water-quality variables were assessed against TCVN 13656:2023 and integrated using the Aquaculture Water Quality Index (AWQI). In 2025, pH, ammonium nitrogen, nitrite nitrogen, and chemical oxygen demand generally met the applicable requirements, whereas salinity, alkalinity, orthophosphate, and total Vibrio counts varied markedly across space and time. Mean AWQI values ranged from 82.8 ± 21.9 in Quang Tri to 96.0 ± 5.9 in Ha Tinh. The 2021â2025 series did not indicate a clear long-term decline; however, low AWQI values occurred mainly from April to August, coinciding with increases in suspended solids, nutrients, and Vibrio. The results highlight the influence of estuarine hydrology, rainfall, and catchment-derived pollution on source-water quality. Adaptive seasonal and event-based monitoring, stronger pollution-source control, settling ponds and intake-water treatment, and integration of monitoring with hydro-meteorological forecasts are recommended for early warning and risk reduction.