Abstract:
Management of good quality ground water is a prime factor for sustenance of life. Use of nitrate
contaminated drinking water is well known risk factor for infant methemoglobinemia and various
types of human cancer. There is a possibility of contamination of nitrate nitrogen in agro wells due
to intensive use of inorganic fertilizer in permeable soil with shallow ground water. Objective of
the study was to measure the nitrate nitrogen in selected agro wells and observe the temporal
variation. Twenty wells were selected randomly from the Kanthapuram areas who have been
cultivating vegetable crops for long period of time. Monthly water samples were collected from
December 2008 to February 2010 to analysis Nitrate Nitrogen. Samples were drawn from the wells
approximately at the levels of 30cm depth below the free water surface. Nitrate nitrogen was
determined by colorimetric method (Brucine method). Mean Nitrate nitrogen in the study area was
12.2mg/l from December 2008 to June 2009 and 95 % of the wells were above WHO permissible
limit of 10mg/l. The depth of the well varied from 6 m to 12 m and around 70% of the farmers
apply the inorganic fertilizer above the recommended level. Intensive use of fertilizer and shallow
ground water in permissible soil could be the reason for high nitrate nitrogen in agro wells. But mean
nitrate nitrogen from August 2009 to February 2010 was 1.2 mg/l. Phyto remediation of nitrate
nitrogen in shallow agro wells by available perennial plants around the wells during severe drought
period from May 2009 to September 2009 could be the reason for low nitrate nitrogen. Mean nitrate
nitrogen from December 2008 to June 2009 was significantly higher than mean nitrate nitrogen from
August 2009 to February 2010 after severe drought (p= 0.000).
