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