Impact of pit toilet leachate on groundwater chemistry and role of vadose zone in removal of nitrate and E coli pollutants in Kolar District Karnataka India

Given the many problems associated with flush toilets and the sewerage system, pit toilets offer a viable solution in India. However, the use of soakpits raises the question of groundwater contamination. This paper assesses the impact of pit toilet leachate on groundwater quality in Mulbagal town (pop ~ 60,000) in Karnataka relies on pit toilets, and uses groundwater for drinking.

Methodology:

Results:

Analysis indicates that 'rock weathering mechanism controls the chemistry of groundwater outside the town (PHS samples), while, evaporation-crystallization controls the chemistry of groundwater inside the town (ITS samples)'.
The study also looks at the efficacy of the vadose zone in the removal of pollutants. The vadose zone is the soil layer between the land surface and the top of the water level. It found that wells with water table depths of 25m or greater are free from E-coli contamination.

Conclusions:

Previously published in the Environmental and Earth Science Journal, DOI 10.1007/s12665-012-1794-9