Geogenic contamination

Accidentally spilled chemicals in river

Groundwater contains some natural impurities. The types and concentrations of natural impurities depend on the nature of the geological material through which the groundwater moves and the quality of the recharge water. Natural sources of groundwater contamination refer to an array of water quality problems, including: natural deposits of salts, gypsum, nutrients and metals in soils that leach into surface and groundwaters; warm weather and dry conditions that raise water temperatures, depress dissolved oxygen concentrations, and dry up shallow water bodies and low-flow conditions and acids from decaying leaves that lower pH and dissolved oxygen concentrations in swamps draining into streams.

Groundwater moving through sedimentary rocks and soils may pick up a wide range of inorganic compounds such as magnesium, calcium and chlorides. Some aquifers have high natural concentrations of dissolved constituents such as arsenic, boron and selenium. The effect of these natural sources of contamination on groundwater quality depends on the type of contaminant and its concentrations. 

Natural occurring pollutants include the following:

  • Microorganisms
  • Dissolved Solids & Chlorides
  • Radionuclides
  • Radon
  • Nitrates & Nitrites
  • Heavy Metals
  • Fluoride