Seasonal Variation and Key Parameters Influencing Surface Water Quality in Xa No Canal Segment Belonging to Vi Thanh District, Hau Giang Province, Vietnam

Abstract

The study was conducted to assess the surface water quality on Xa
No canal in Vi Thanh district, Hau Giang province. Surface water
quality samples were collected at 3 locations with a frequency of 4
times per year including March, May, August and October 2020 from
the Department of Natural Resources and Environment of Hau Giang
province. The results showed that the temperature, pH and NO3
-
-N
in the study area is still within the allowable limits of QCVN 08-
MT:2015/BTNMT, Column A1. Surface water in the study area was
contaminated with organic (low DO, TSS, BOD, high COD),
nutrients (NH4
+
-N and PO4
3-
-P exceeded permissible limits), heavy
metals (Fe) and coliform. Water quality has obvious seasonal
variation in which DO in August and TSS, BOD, COD, NO2
-
-N in
May were significantly higher than those in other months. NH4
+
-N
and PO4
3-
-P in October were higher than those in March, May and
August. Meanwhile, iron and coliform in March were significantly
lower than those in other months. The results showed that the WQI
(25 to 52) classified the water quality was from bad to moderate in
which water quality in October was better than that in the other
months. Surface water quality at Xa No canal was influenced by five
potential polluting sources which caused 92.4% of water quality
variation. All monitoring parameters (pH, temperature, TSS, DO,
BOD, COD, NH4
+
-N, NO2
-
-N, NO3
-
-N, PO4
3-
-P, Fe and coliforms had
impact on water quality and need to be continuously monitored.
However, NO2
-
-N, BOD can be considered to reduce because it can
be predicted from other indicators such as DO, COD and NH4
+
-N.
Environmental management agencies need to find solutions to
improve water quality, especially organic matters and
microorganisms.