Contrarily villages which are located in a similar proximity to irrigation systems but source drinking water from wells fed by natural springs are less affected by CKDu Jayasekara 2013 Moreover as the distribution of the disease correlates with predominantly agricultural areas certain studies have suggested that use of agrochemicals such as pesticides weedicides and insecticides could be linked with CKDu Particularly there is a postulate that pesticides with proteinuric nephropathy are a possible cause of CKDu Wanigasurya 2011 This postulate is based on the fact that individuals in these farming communities get exposed to harmful agrochemicals that come from variety of sources including runoff from upstream agricultural lands and during agricultural operations Wimalawansa 2014 Nevertheless Chandrajith et al 2011 reported that none of the published findings directly link these chemicals to CKD as the available data are insufficient and inconclusive Extensive use of fertilizers that has resulted from the fertilizer subsidy given by the government is also believed to be a possible cause for the contamination of drinking water in the region Vegetable farmers in the hill country use excessive amounts of agrochemicals and phosphate fertilizers irresponsibly due to unavailability of proper regulations Even though they use much higher amounts of these chemicals than that is used in the dry zone vegetables and potatoes only absorb a fraction and a larger quantity is being rapidly washed away due to the frequent rainfall and unique terrain of the region
Unfortunately via Mahaweli River and its tributaries these chemicals end up in the NCP eventually Thus it is justifiable that a higher prevalence of CKDu is seen in the NCP while no patients were detected in hill country Wimalawansa 2014 Metals metalloids and minerals have been the focus of many studies related to CKDu since its emergence inn Sri Lanka A popular hypotheses is that high levels of metals including cadmium and fluoride as well as the complex interactions between dissolved sodium and calcium in the presence of fluoride are the probable causes to CKDu in many endemic areas in Sri Lanka Chandrajith et al 2011 Similarly cadmium has also been heavily investigated as a potential causative agent in CKDu endemic areas as certain studies that analyzed the levels of heavy metals on water soil plants and fish from the affected areas have suggested a likely relationship between the high levels of cadmium in the environment and CKDu The main sources of cadmium has been identified as triple super phosphate fertilizers and weedicides which are intensively applied in the affected areas of NCP Moreover cadmium levels were found to be much higher than the recommended safe level of 5µg L in several tributaries of river Mahaweli which is the main irrigation source in the affected area Bandara 2011 However two recent studies by Nanayakkara et al 2014 and Ranago 2015 that investigated the urinary excretion of a number of heavy metals including uranium cadmium arsenic and lead concluded that the presence of these metal contaminants in drinking water cannot be clearly linked to CKDu
Thus a majority of researchers have suggested a synergistic effect from the combination of several heavy metals agrochemicals and other environmental factors Rajapakse et al 2016 Fluoride was also believed to be correlated with CKDu as significantly elevated fluoride levels were detected in the affected areas Rajapakse et al 2016 This hypothesis was also based on the clinical fact that fluorosis and kidney damage can be caused by prolonged exposure to high concentration of fluoride ions Partanen 2002 However it is notable that some areas with high fluoride levels in water such as Ampara and Pulmudai do not have a high prevalence of CKDu Thus considering the fact that people in these areas have been consuming fluoride rich water for generations without significant ill effects World Health Organization dismissed this hypothesis in 2013 Wimalawansa 2014 Considering the available hypotheses it is evident that CKDu is correlated with multiple factors that may have resulted from contamination of water and the environment due to agricultural or associated human practices Wimalawansa 2014 Wimalawansa 2014 further stated that agrichemical use and massive subsidies expanding technology unfair distribution of essential services and basic human needs inequalities and interfering politics are all externalities that have negatively contributed to changing the course of the health and well being of the population of the NCP Major agricultural malpractices and management issues that are leading to this environmental contamination can be listed as follows Carless use and overuse of agrochemicals including pesticides weedicides and chemical fertilizers as a result of government fertilizer subsidy Lack of awareness in farmers regarding the effects of improper use and chronic exposure to these agrochemicals Lack of proper controls regarding selling and distribution of agrochemicals Not using proper personal protecting equipment in handling toxic chemicals Frequent dredging of canals and reservoirs exposing the toxic metals deposited deep in the soil layers
