Can natural, clean, soil also be contaminated?
Britain’s industrialised history means that we spend a lot of time undertaking risk assessments on pre-used land for common, industrial-related contaminants such as Arsenic, lead and other heavy metals which are toxic to human health.
But these metals also occur naturally in soils in certain areas of the UK as a result of mineralisation of the parent bedrock.
Whilst these soils have not been contaminated by an external industrial source, they could still pose a potential threat to human health.
However, the published screening levels that are widely used to determine whether or not soil is “contaminated”, are derived from scientific literature which tends to be biased towards more hazardous industrial exposure to metals. This can lead to an overestimation of risk from natural soils and unnecessary remediation in the form of clean cover systems is often the outcome.
If the risks are properly assessed, with thorough characterization of topsoil and subsoil, coupled with a detailed QRA, we’ve found that the risks are often not as great as first thought.