Measurement of site contamination

On larger sites, a common approach is to sample the whole site on or within a grid, with centres set between 20 and 50 metres apart, and then sample more intensively where higher or anomalous values are reported. This can then be extended by additional sampling at locations where features are noted, such as the presence of waste materials or disturbed ground, or where contaminating activities are known to have taken place. This can be linked to the delineation of site zones for risk assessment purposes. 

A herring-bone sampling design has been recommended13 for areas of relative 

12 British Standards Institution, Code of Practice for Investigation of Potentially Contaminated Sites, British Standards Institution, London, 2000. 

13 Department of the Environment, Sampling Strategies for Contaminated Land, CLR 4, Department 

The methods used for laboratory testing of held samples should have validated performance and be conducted within a rigorous quality management system. To avoid reliance on poor data, great care is needed to ensure that the test results reported are derived from methods of known performance that have been applied exactly. This can be confirmed by ensuring that full validation and quality control information is available to support test data.14 

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