Author(s): Tran Dang An; Truong Thu Hang; Trieu Anh Ngoc; Vo Le Phu
Linked Author(s):
Keywords: Water quality assessment; Water quality index (WQI); Irrigation water quality indexes (IWQIs); Soc Trang; Mekong Delt
Abstract: Water quality is the first consideration in choosing water resources for many purposes, especially for drinking and irrigation. In the Mekong Delta, the quality of water resources deteriorated severely by variable pollutant sources such as wastewater, arsenic and seawater. This paper aims to assess water quality for domestic and irrigation uses in coastal areas of Soc Trang province, the Mekong Delta, Vietnam. The water quality index (WQI) and variable irrigation water quality indexes (IWQIs) such as sodium adsorption ratio (SAR), Kelly's ratio (KR), residual sodium carbonate (RSC), solute sodium percentage (SSP) and permeability index (PI) were deployed to evaluate water quality regarding domestic and agricultural water demands. Water samples were taken by seasonal characteristics and tidal regime in 2013 and 2014. Main parameters include Temperature (T0C), Electrical Conductivity (EC), pH, Dissolved Oxygen (DO), Total Dissolved Solid (TDS), Total Hardness (TH), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), bicarbonate (HCO3-), chloride (Cl-), sulfate (SO42-) and nitrate (NO3-) were analyzed for the calculation of WQI and IWQIs. The results show that, almost groundwater samples at shallow aquifers, some of the deeper aquifers and river water samples in dry season were seriously affected by seawater intrusion and nitrate contamination. This means that these water resources cannot use for both drinking and agricultural purposes. Meanwhile, most of groundwater samples at middle and lower Pleistocene aquifers and surface water in rainy season seem to be good for both drinking and irrigation. However, groundwater source in Soc Trang province has been excessively extracted without suitable regulation and appropriate management. This situation may threat to groundwater source because it can be easily contaminated by seawater intrusion and wastewater. In order to extract, use and manage effectively fresh water source in coastal areas in the Mekong delta, emergent management practices should be considered.
Year: 2014