Nitrate and fluoride contamination in groundwater is one of the major emerging problems of Northern-Karnataka region of India. Fluoride pollutants in groundwater are responsible for dental and skeletal fluorosis whereas the nitrate contamination is highly responsible for methemoglobinemia (blue baby disease), respiratory system, kidney and thyroid in children as well as adults. The study has been carried out to identify the geochemical processes and mechanism responsible for releasing of nitrate and fluoride pollutions in the region. Sampling has been done in the both monsoon periods such as pre-monsoon and post-monsoon seasons. Fluoride concentration varies from 0.652 mg/L to 1.97 mg/L in pre-monsoon whereas the nitrate concentrations vary from 12 mg/L to 96 mg/L. Post-monsoon sample shows that the fluoride and nitrate varies from 0.76 to 1.53 mg/L and 16 mg/L to 77 mg/L respectively. The worst fluoride-affected villages are Jidga, Kamanalli, Padsawli, Sakkarga and Nagelagaon. Several diseases such as dental and skeletal fluorosis have been identified in region. Inter-trappean beds and enhance rate of weathering of fluoride bearing minerals may be responsible for fluoride contamination whereas excess use of fertilizer is generally responsible for nitrate contamination in the region.
Keywords: Contamination, Groundwater, Nitrate, Fluoride, Health risk