Assessment of Groundwater Quality Using Multivariate Statistical Analysis in the Medawachchiya Area and the Huruluwewwa Areas in Anuradhapura District

Abstract

Water is a scarce commodity in North Central Province (NCP) of Sri Lanka and people use groundwater for consumptive purposes. 85% of the rural population in the NCP obtains water from shallow and deep wells. However, human health is affected by water quality in various ways. Therefore, the present study was focused to identify the quality of groundwater in Madawachchiya and Huruluwewa by using multivariate statistical analysis. Medawachchiya area and the Huruluwewa area were both separately divided into 30 quadrants and the middle point of each was taken as a sampling location. Altogether there were 60 water sampling locations. During the survey period of two years, twenty-four water quality parameters (Temperature, DO, pH, Electrical Conductivity (EC), Total Alkalinity (TA), Total Hardness (TH), Chloride (Cl), Nitrate, Phosphate, Fluoride, sulfate, Fe, Zn, K, Na, Mg, Ca, Cr, Cd, Se, Al, Pb, Mo, and As) were analyzed. Data analysis was performed by using the multivariate statistical analysis techniques as a tool. Five parameters including pH (p-0.787), fluoride (p-0.497), Fe (p-0.116), Mg (p-0.06) and as (p-0.532) were not significantly different, while all other parameters were significantly different in both areas. Three clusters in Medawachchiya and five clusters in Huruluwewa were identified. However, Medawachchiya area (13%) indicated very less amount of groundwater samples which were good for consumptive purposes than Huruluwewa (37%). Strong positive correlations were appeared in between TH vs EC (p-0.744), Orthophosphate vs K (p- 0.770) in Medawachchiya study area and TH vs EC (p-0.830), Cl vs EC (p-0.807), EC vs Na (p-0.778), EC vs Mg (p-0.788), Cl vs TH (p-0.719), TH vs Ca (p-0.715), and TH vs Mg (p-0.811) in the Huruluwewa study area. The water quality of both areas were moderated by the hydrogeochemical and agrochemical influencing factors. Study revealed that, majority of the groundwater wells were unsuitable for drinking purpose without any pre-treatment.