Sources and factors influencing groundwater quality and associated health implications: A review

Groundwater is essential for man's well-being and survival and is imperative for promoting public health. A wide range of groundwater quality studies have been conducted globally. However, there is no categorical study that specifically synthesizes the sources and factors that threaten groundwater quality. This study considered 15 countries in this review. The review showed that globally groundwater systems are predominantly contaminated with microorganisms, heavy metals, trace elements, organic compounds, and agrochemicals (dichlorodiphenyltrichloroethane/1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and dichlorodiphenyldichloroethylene (DDE)). Though organic matter levels in groundwater is less studied in groundwater, it also poses debilitating health risks including bladder, rectum, and colon cancers. Geologic processes and lithological and pedological factors, climate change, environmentally-unfriendly agricultural activities, poor sanitation practices and landfill management are the most dominant factors that impact groundwater quality. Based on these, it is required that realistic and implementable policies and regulations related to groundwater protection are formulated and enforced. Also, groundwater systems are sited properly to reduce anthropogenic impacts and the likely occurrence of adverse health effects.