Contaminated Land Remediation
Treating contaminated land should be carried out by a specialist contractor, with British Standard documentation setting out the practice of how it should be done. Samples should be taken for laboratory analysis from the soil and any water or gas present.
The report must conclude with any treatment required and an analysis of the cost. In extreme cases, the land may need to be excavated and refilled with topsoil, or a similar hard surface where applicable.
Where the groundwater around the land is contaminated, there may be a need for long term monitoring of the land. Removing the contaminated land is a common solution to long term risks, but a licence for transporting it to another site is required.
Biochemical or fungal treatment to stabilize land contaminants may be an option as a form of natural treatment, but this is only available for certain chemicals. Metals like lead and iron cannot be treated with these methods.
Flushing away contaminants with water or other chemicals can also be performed in some cases, while vacuum suction treatment can deal with petrol and other volatile pollutants, if you intend to build on a former garage site, for example.
If the contamination cannot be taken out of the soil economically, an impervious layer often used to line landfill sites can contain them within it, since at a particular thickness it prevents any gases from migrating through. Plastic linings have been developed for the same purpose and have a more than sufficient life expectancy.
Retesting of contaminated land after treatment is an inevitable task, since only proving that the brownfield site has been effectively cleansed will ensure its authorized development and your safe occupation.
Nick Maynard, Mercatus Land Consultants, May 2005
