What factors are related to the occurrence of VOCs in samples from domestic and public wells?
For both domestic and public wells, hydrogeologic factors associated with the likelihood of detecting volatile organic compounds (VOCs) included high aquifer recharge and high soil permeability. Anthropogenic factors included population density, percentage of urban land use near the sampled wells, and proximity of hazardous-waste facilities. Dissolved-oxygen concentration was an important factor associated with the occurrence of individual VOCs. For public well samples, increased MTBE occurrence was associated with local use of this oxygenate in gasoline. Public wells may be more vulnerable to VOCs than domestic wells due to large withdrawal rates, proximity to developed areas, larger capture zones, greater drawdown, and faster movement of water from the top of the water table to the well screen.
