Some of the common contamination sources of groundwater include untreated waste from septic tanks, toxic chemicals from underground storage tanks and seepage from leaky landfills. In addition, pesticides and fertilizers also find their way into groundwater supplies over time. Road salt, toxic substances from mining sites and used motor oil find their way into wastewater and leach into underground water (Groundwater Foundation 2018). Furthermore, rocks that contain certain minerals such as fluoride may gradually dissolve, altering the chemical composition of aquifers and rendering the water unsafe for consumption.
From collection: Sanitation and Wastewater Atlas of Africa - Ecosystems