NICE TO KNOWContaminated sites contain substances in or under the land that are actually or potentially hazardous to health or the environment. Areas with a long history of industrial production will have many sites which may be affected by their former uses such as mining, industry, chemical and oil spills and waste disposal. Contamination can also occur naturally as a result of the geology of the area, or through agricultural use. Environmental remediation deals with the removal of all substances that pollute soil or groundwater. These remedial actions should be taken as this can impact negatively on human health and the environment. Remediation technologies are many and varied. There’s chemical-/physical and biological methods. They can generally be categorized into ex-situ and in-situ methods. Ex-situ methods involve excavation of affected soils and subsequent treatment at the surface as well as extraction of contaminated groundwater and treatment at the surface. In-situ methods seek to treat the contamination without removing the soils or groundwater. In situ oxidation technologiesIn situ oxidation technologies have become known for remediation of a wide range of soil and groundwater contaminants. Remediation by chemical oxidation involves the injection of strong oxidants such as hydrogen peroxide, ozone gas, potassium permanganate or persulfates.