Abstract: In alluvial areas, having intensive agricultural practices,
continuous loading of agrochemicals is a common phenomenon. This, mixed with
irrigation water transport through the unsaturated zone, is likely to result in
groundwater contamination. A study has been initiated to assess the extent of
groundwater contamination in the Indian Agricultural Research Institute (IARI)
farm area, New Delhi, using Geographic Information System (GIS) technology.
Nitrate, fluoride and potassium contents in farm groundwater varies from
<1.0 to 80.0 mg/L, <1.0 to 1.87 mg/L and 1.6 to 18.3 mg/L respectively,
suggesting contamination contributed by different sources. The investigations
indicate that the groundwater pollution in the northeastern parts (TW-16) is
contributed by point source, while in the western parts (TW-CPWD2 and TW-CPWD1)
it is contributed by the sewage disposal water showing high values of nitrate
i.e. >45 mg/L. Groundwater samples, in eastern and western parts (TW-GEN1
and TW-CPWD2), show high values of fluoride 1.87 and 1.76 mg/L respectively.
The central part of the farm area is the zone of extensive agricultural
activities where nitrate contamination is mainly contributed by the nitrogenous
fertilizers. Urgent need to check the groundwater contamination by
adopting/modifying agronomical management practices is advocated.
Keywords: Groundwater, contamination, nitrate, intensive agriculture, chemical fertilizers
