Pollution Sources

Pollution may result from natural processes (termed geogenic) or from human activities (termed anthropogenic). Geogenic contaminants are predominantly toxic metals such as mercury, lead, and arsenic, but can also include radionuclides and organic compounds such as hydrocarbons. 

Contaminants from anthropogenic sources account for most soil pollution case studies, and include multiple chemical classes. The specific contaminants sourced to soil are determined by the human activity.

Contamination from a single localised point of discharge is called point source pollution. Examples of point-source pollution events include leaks from fuel station tanks, discharge points of wastewater treatment plants, and leachate from a landfill site.  

Pollution sourced from more widespread activities, such as pesticide runoff from agriculture or the release of compounds into the air from bushfires, is termed diffuse pollution.  

Point-sources tend to cause higher contaminant concentrations within a smaller area, which can be easier to isolate and treat; diffuse sources usually cause lower concentrations of pollution dispersed over a larger geographic range, which often makes treatment or removal impossible.