| Abstrakt: |
Groundwater is an essential and finite resource in the world. Numerous knowledge gaps remain in the understanding of groundwater resources in Sri Lanka, mainly due to the lack of accurate data. The purpose of this study is to assess the water quality in groundwater and its spatial distribution in Negombo-Muthurajawela area in Sri Lanka. The data collection was conducted at the beginning and at the end of south west monsoon (May and September, respectively) in 2013. A pilot survey was carried out using 116 dug wells. A total of thirty-one dug wells were selected for physiochemical analysis. In situfield testing of electrical conductivity (EC), salinity, and pH were carried out and laboratory tests were performed for HCO3−, Na+, K+, Ca2+, Cl−, SO42−, Mg2−, PO43−, NO3−, and total hardness (TH). Principal component analysis (PCA) was performed to assess water quality and interpolation technique in ArcGIS was performed to analyze and prepare spatial distribution maps of water. Sri Lankan standards for drinking water were used to determine the threshold levels of physiochemical parameters. The results of the PCA reveal that thirty-one observation wells can be classified under three main components: the first based on the impact on EC, HCO3−, Na−, K+, Cl−, Mg2−, and TH; the second component considering the pH, HCO3, Ca2+, SO42−, PO43−, and TH; and the third component based on NO3−. These three components evidence the role of salt water intrusion, the influence of Muthurajawela wetlands, and the anthropogenic discharges on groundwater quality in the Negombo-Muthurajawela area. |
