Should groundwater be used for drinking purposes?

Groundwater is an important source of drinking water in many parts of the world, but is it safe? How should we make it safer? Pumped from underground aquifers which are recharged by percolation of rainwater through the soil, groundwater is freshwater that may harbour various organic, inorganic and microbiological contaminants. Specifically, inorganic contaminants such as boron, nitrate, chromium, manganese, copper, nickel and arsenic ranks as serious pollutants with human health significance. Current methods for treating groundwater follows the conceptual thought flow for river and reservoir water treatment: sedimentation, coagulation, sedimentation, slow sand filtration, and disinfection by chlorine and ultraviolet light. However, the above process train is unable to remove trace contaminants such as heavy metals, which may impact on human health. Thus, depending on the contaminants load, groundwater may require expensive advanced water treatment methods such as hollow fibre ultrafiltration and reverse osmosis. High pressure and with high energy consumption, ultrafiltration and reverse osmosis addon to conventional drinking water treatment process would make groundwater safe for drinking, but society needs to judge the cost-benefit ratio in the case where alternative cleaner sources of drinking water is available, for example, rivers and freshwater reservoirs. Overall, while technologies exist to make groundwater safe for consumption, high price and poor accessibility of these advanced water treatment techniques such as reverse osmosis makes siting a settlement or town near a river or freshwater lake critical from the perspective of provision of clean drinking water. Additionally, faster than recharge rates withdrawal of groundwater also led to untoward land subsidence, which may bring about other issues such as saltwater intrusion into groundwater aquifers near coastal areas. Thus, if freshwater is available from a nearby lake or reservoir, groundwater use in the view of an expanding population is a poor policy option as the easier and safer route is often expanding water catchment areas and freshwater reservoirs.