New contaminated guidelines aimed at giving realistic acceptable levels of contaminants rather than the existing conservative values has met with mixed reaction from industry.
Contaminated Land: Applications in Real Environments’ (CL:AIRE) new Category 4 Screening Levels (C4SL) consist of estimates of contaminant concentrations in soil that are considered to present an “acceptable” level of risk, within the context of Part 2A of the Environmental Protection Act (1990).
The methodology for deriving both the previous Soil Guideline Values and the new C4SLs is based on the Environment Agency’s Contaminated Land Exposure Assessment (CLEA) methodology.
The project is presented as a demonstration of the methodology, via the derivation of C4SLs for six substances – arsenic, benzene, benzo(a)pyrene, cadmium, chromium (VI) and lead. The report stops short of providing “final C4SLs” for any substances but, instead, presents “provisional” values for six substances upon which finalised C4SLs could be based.
The document has been criticised for failing to move away from pre-existing low values with the values for lead lower than in previous guidance. One of the main failings of the report, according to the specialists in the sector, is that the guidance still needs to be used in conjunction with standards set by the Environment Agency, Defra and a number of other organisations.
“The document doesn’t deliver a single source for soil and water screening values that the US’s Environmental Protection Agency,” one source told GE. Another industry specialist said that the new screening risk model was too complicated and only specialist toxicologists will be able to understand it and use it effectively.