Groundwater Quality Assessment in Anuradhapura for Domestic Purposes

Abstract

The North central province plays the main agricultural role in Sri Lanka as a developing agricultural-based economy country in the world. Excessive amount of nitrate and fluoride in groundwater consumption is becoming a crucial issue on human health in Sri Lanka, especially in the North Central part of the country. Dental fluorosis and skeleton fluorosis are the major health impacts based on an excessive amount of fluoride as well as presumption on causing chronic kidney disease (CKD). Nitrogenous compounds in groundwater for drinking have been considered possible risk factors for oesophageal cancer and haemoglobinemia or blue baby syndrome. Human activities and natural processes have polluted groundwater. Having a lack of understanding of the actual need for fertilizer, farmers usually tend to apply the surplus amount, thus increasing nitrogen pollution. Accordingly, this research was conducted to deepen the understanding of the distribution of fluoride and nitrate in groundwater in the Anuradhapura area in terms of geological and anthropogenic influences on groundwater quality. Well water samples were collected from intensive agricultural activity areas in Anuradhapura. Physical and chemical parameters were analyzed to identify whether the higher nitrate and fluoride or any compound of a mixture of heavy metals such as cadmium and/ or arsenic is the actual cause for kidney and other health-related issues among the community. Water samples' pHs were in the range of 6.7-7.7. All the wells can be categorized as low salinity water. Turbidity average of 3.51 NTU range of 1-8 NTU was found to be mainly contributed by nitrate at the average of 28.725 mg/L and ranged from (22-131) mg/L of nitrate. In addition, fluorite was found high in Anuradhapura with an average of 0.6 mg/L and ranged from (0.4 - 1.7) mg/L. Sulphate level was also high with an average of 178mg/L and ranged from (58-505 mg/L). There was no significant effect of heavy metals such as cadmium, arsenic, iron, and copper concentrations which were below the permissible level of 0.01mg/L. The research clearly indicates the abundance of nitrate and fluoride in groundwater, especially in the dry zone. The major sources are fluoride-bearing minerals in bedrock and soil zone. In addition to that, the influence of agriculture which causes excessive nitrate levels in groundwater, is apparent, irrespective of climatic zones.