Poor sanitation infrastructure and inadequate sewerage disposal are the major contributors to groundwater quality degradation. Microbial and chemical contaminants present in human wastewater put the groundwater resources at significant risk as the pollutants are mobilised from the unsaturated zone until they reach the groundwater.
The transport of microbial pathogens (bacteria, viruses, protozoa and helminths) in groundwater is limited by the survival time and attenuation; such as filtration and adsorption. These processes will limit the microbiological impact of sewage on groundwater resources; however, vulnerable aquifers (unconsolidated deposits, fractured systems, shallow aquifers) are more susceptible to pollution. The main inorganic pollutants associated with sewerage are nitrate and chloride, which may be altered by the addition or mix of other substances or may be oxidised depending on environmental conditions. The inorganic pollutants represent a significant threat to human health when groundwater is used for drinking purposes as it also increases the economical investment for water treatment.
The required actions towards groundwater protection should be linked to sanitation initiatives in urban areas and developing countries, increase the capacity to monitor and manage groundwater with essential data to influence policies on groundwater protection strategies.