Sri Lanka is characterized by well-demarcated climatic zones based on the rainfall pattern known as wet zone, dry zone and intermediate zone. Groundwaters in these three zones are extracted mainly for drinking and irrigation from metamorphic hard rock aquifers and saprolite developed on metamorphic rocks. Detailed hydrogeochemical investigations were carried out covering these three climatic zones in order to characterize the groundwater. A total of 166 groundwater samples were collected representing three climatic zones and analyzed for their major and trace element geochemistry. The results indicate a clear difference in the geochemistry of groundwater between climatic regions, whereas semiarid dry zone groundwater is characterized with higher dissolved mineral contents compared that of the wet and intermediate zones.Low pH levels were noticed in the wet zone areas, while high calcium and fluoride contents were observed in the dry and intermediate terrains. Remarkably, high phosphate contents were observed in all three regions, indicating the influence of fertilizer application on groundwater. Particularly in the dry zone regions, the groundwater chemistry is mainly controlled by rock-water interactions and ion exchange processes in which high mineral contents are added from underlying metamorphic rocks to the drinking and irrigation water. The results indicate that groundwater in the dry zone area is under stress compared to other climate areas, but in the wet zone groundwater shows remarkable influence of anthropogenic activities.

In this article, the current scientific evidence of Chronic Kidney disease with unknown aetiology (CKDu), were critically reviewed and harnessed with other relevant literature with a view to justify the possible causative reason(s) for this chronic health problem. To this end, authors first reviewed the literature on socioeconomic , environmental, meteorological, health and geo-environmental/chemical aspects in relation to the CKD of unknown aetiology in Sri Lanka and then studied the known aetiology of CKD (key medical facts) in detail highlighting a comprehensive list of causes. Based on the nature of economic development in the CKDu prevailing area, previous studies have suggested that the causative factor for CKDu is probably environmental and is related to the nature of anthropogenic activities. Therefore, authors investigated subject more into the chronic exposure to heavy metals associated with agricultural activities. Potential sources of heavy metals in the area are mentioned. The geochemical mobility and health effects of three selected elements namely arsenic (As), cadmium (Cd) and Lead (Pb) are studied in detail. The current scientific observations reported on CKD were evaluated with established chemical, geochemical, and health risk of As, Cd and Pb. According to the review, it can be justified that CKDu of the North Central Province (NCP) in Sri Lanka is a decease caused by the chronic exposure and cumulative effects of elevated levels of heavy metals associated with agricultural activities.

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Chronic kidney disease with uncertain etiology (CKDu) is an emerging health problem in Sri Lanka, particularly among the dry-zone farming communities that use groundwater for drinking. We investigated the quality of groundwater in an area where both high- and low-prevalence clusters of CKDu have been recorded. Eighty-four groundwater and five surface water samples, covering the selected region, were collected and analyzed for both major anions and cations. The groundwater in the region is mainly of the Ca-Mg-HCO3 type, probably due to the long residence time in fractured hard rock aquifers in this region. Irrespective of the CKDu prevalence, over 50% of samples exceeded the recommended limits for EC/TDS, alkalinity, hardness, and Mg2+ content in groundwater. Water hardness in CKDu clusters was dominated by Mg2+. High fluoride content up to 4.0 mg/L was also found in most groundwater samples from the region. The water quality index (WQI) values indicated that 42% of the groundwater samples in regions with no or low CKDu prevalence and 49% of the samples in regions with high prevalence were poor in quality. The spatial distribution of WQI and fluoride concentration overlapped, indicating the direct influence of fluoride on the groundwater quality in the study region. In addition, regions with higher WQI values overlapped with the CKDu hotspots, indicating the direct impact of groundwater quality on the disease prevalence in the studied river basin. The WQI can be used to effectively demarcate areas with possible groundwater-related health effects in the dry-zone regions of Sri Lanka.

p < 0.05), adoption of chemical pesticide reduction methods (χ2 = 12.452, p < 0.05) and received training on effective use of pesticides (χ2 = 9.427, p < 0.05). Several reasons of misuse of pesticides by farmers were identified. Among them, lack of technical knowledge on pesticide application and integrated pest management (IPM) practices were the main courses. Most of the farmers tend to use pesticides as a precautionary safety measure before any pest or disease symptoms emerge. Further, pesticide retailers had a strong influence on the selection of pesticides by farmers suggesting that agro-marketing has a significant influence over pesticide usage among farmers. The canonical correspondence analysis indicates that farmers' knowledge of the correct handling of pesticides were positively influenced by the farmers' level of education and training received on pesticide usage (p < 0.05). The study suggests the importance of training, extension services and farmer education to improve the levels of knowledge and awareness of farmers on the risks of pesticides to human health and environmental pollution.

This paper compares the effects of adding fertilizer in nitrate pollution of groundwater in the Udunuwara area in Sri Lanka and the Shiroishi Plain in Japan. Excessive application of nitrogen fertilizers to soils contributes to contamination of groundwater by nitrates. As nitrate is one of the most identified contaminant in groundwater several environmental protection agencies maximum contamination level for nitrate is 10 mg/l as NO 3 -N. The problem becomes severe in rural areas where people depend entirely on dug wells in the shallow groundwater table for their drinking water supply. Several locations were selected from the Udunuwara area of Sri Lanka for the detailed study. Nineteen shallow dug wells and 4 deep tube wells were selected for water sampling beginning of January to March 1998. Shiroishi Plain in Japan reclaimed from the Ariake Sea has a soil layer consisting of Ariake clay. The total 82 drug wells of average depth 1.5 m had been drilled around the area. Sample were collected in December 2000 and continued for one year around. Nitrate concentration in groundwater was measured by Cadmium reduction method.The results showed a varying nitrate distribution pattern compared to that the Udunuwara area. The effect of fertilizer application on groundwater depends on soil type, fertilizer type and amount used, crop type and climatic condition. The highly permeable soil around Udunuwara area showed that shallow groundwater is highly vulnerable for nitrate than the poorly drained soil of the Shiroishi Plain in Japan. As the people living in Shiroishi Plain use deep groundwater for domestic purposes, drinking water is safe (less than Maximum Contaminated Level for nitrate in drinking water for Japan-10 mg/l as NO 3 -N) as far as the nitrate contamination is concerned. The results of these studies suggest that applying the correct rate of N fertilizer at the optimum time would have a substantial effect on reducing nitrate-N losses.