Seasonal Variation of Surface Water Quality in the Water Bodies in the Plain of Reeds, a Vietnamese Mekong Delta Area

Abstract

This study was conducted to evaluate surface water quality in rivers
and canals in the Plain of Reeds, Dong Thap province for the year
2020 using national technical regulation on surface water quality
(QCVN 08-MT: 2015/BTNMT) and water quality index (WQI).
Surface water quality parameters of turbidity, pH, temperature,
dissolved oxygen (DO), suspended solids (TSS), biological oxygen
demand (BOD), chemical oxygen demand (COD), nitrite (N-NO2
-
),
nitrate (N-NO3
-
), ammonium (N-NH4
+
), orthophosphate (P-PO4
3-
),
coliform, and E. coli. The results showed that BOD, COD, coliform
and E. coli at most of the monitoring locations exceeded QCVN 08-
MT: 2015/BTNMT, column A2 pointing out that surface water quality
was being seriously impaired. Temperature, pH, DO, and E. coli were
not significantly different between the seasons. TSS, BOD, COD, NNH4
+
, N-NO3
-
, P-PO4
3-
, and coliform were high in the rainy season
while N-NO2
- was high in the dry season. WQI values ranging from 24
to 64 indicated the poor water quality in densely populated, industrial
areas along Tien and Hau rivers. Further studies should focus on
specific water polluting sources for sustainable surface water quality
management