The level of nitrate in drinking water was tested from groundwater artesian wells located within farms and surrounded by crops (mostly rice and wheat rotations).
Nitrate pollution in groundwater is associated with nitrogen loads in the environment. In urban areas, it is associated with sewage and in agriculture areas, with livestock sources and nitrogen fertiliser inputs. Nitrate pollution in drinking water can have serious health impact on humans, especially for babies and children. The most significant potential health effects of drinking water contaminated with nitrate are the blue-baby syndrome (methemoglobinemia) and cancer.
A chemical intensive model of agriculture was introduced in India in the 1960s as part of the Green Revolution. This model and the supporting government policies, such as the chemical fertilizer subsidy policy, provoked indiscriminate use of chemicals. This has not only led to deterioration of the environment but also degraded and contaminated the natural resources base, and is now posing a threat to human health.
Ironically, this intensive farming practice is also not living up to its promise of sustained increase in food production. As a consequence, food production is now affected by diminishing returns and falling dividends in agriculture intensive areas. Application of nitrogen fertilizers compromises future food production by degrading soil fertility, and compromises the health of the farmers and their families by polluting the drinking water they depend on. The situation is alarming as the intensive model of farming has already depleted the groundwater. This region might be suffering from widespread nitrate pollution on its diminishing sources of drinking water.
As a part of the study, groundwater was tested from artesian wells located in farms away from other potential sources of nitrate contamination (animals, human sewage), in order to focus on the impact of fertilizer application. Farms located in three districts (Bhatinda, Ludhiana, Mukhtsar) in Punjab where fertilizer consumption is highest were sampled.
As control points, two wells that are also monitored by the Central Ground Water Board (CGWB) were sampled. These wells are located within the villages, with high pollution probably coming from concentration of human sewage and cattle. The comparable values from these tests and from the reported values by CGWB point to the agreement between the two methodologies.
The investigation in three districts of Punjab shows that 20 percent of all sampled wells have nitrate levels above the safety limit of 50 mg of - nitrate per litre established by the World Health Organisation (WHO). Also, this nitrate pollution is clearly linked with the usage of synthetic nitrogen fertilizers as higher the application of nitrogen (urea) in the adjoining field, the higher the nitrate pollution found in the drinking water from the same farm.
There is an urgent need to shift to an ecofriendly agricultural model, and identify agro-ecological practices that ensure future food security. It is necessary now to acknowledge the pattern of the hazards that is becoming a trend, and address them with research, political will, relevant policy and practices.
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