Identifying Key Variables Influencing Surface Water Quality in Coastal Provinces of Soc Trang and Bac Lieu, Vietnam

Abstract

The study was carried out to assess the quality, main influencing
indicators and sources of impact on surface water quality of coastal
provinces such as Soc Trang and Bac Lieu. Water quality data were
collected at 19 sampling locations in Soc Trang province and eight
sampling locations in Bac Lieu province in 2019 including
parameters of temperature, pH, electrical conductivity (EC),
turbidity (Turb), total suspended solids (TSS), dissolved oxygen
(DO), chemical oxygen demand (COD), biological oxygen demand
(BOD), ammonium (N-NH4
+
), nitrite (N-NO2
-
) , nitrate (N-NO3
-
),
soluble phosphorus (P-PO4
3-
), total Fe (Fe), total nitrogen (TN),
total phosphorus (TP), sulfate (SO4
2-
), chloride (Cl-
), coliforms,
total organic matter (TOC), alkalinity (Alk) and salinity (Sal).
Principal component analysis (PCA) was used to identify the main
factors affecting surface water quality in the study area. In Soc
Trang, the results showed that the water quality shows signs of
pollution by suspended solids, organic matters, nutrients and
microorganisms in the central areas of the city, urban areas, inland
areas and salinity. in coastal areas. The PCA results indicated that
the parameters that need to be selected for monitoring included EC,
TSS, COD, Cl-
, total Fe, SO4
2- and BOD, N-NH4
+
, P-PO4
3-
. In Bac
Lieu, the results showed that the water quality is not suitable for
domestic purposes. The parameters of TSS, COD, BOD, N-NO2
-
,
N-NH4
+ and Cl- all did not meet the permitted standards of QCVN
08:2015/BTNMT (column A2). The PCA results showed the criteria
that need to be considered for monitoring such as pH, salinity,
COD, BOD, TSS, total Fe, Cl-
, DO, N-NO3
-
, alkalinity and
coliforms. The current results provide scientific information for
monitoring water quality in the coastal provinces of the Mekong
Delt