The derivation and use of soil screening values for 
metals for the ecological risk assessment of 
contaminated land: a regulatory perspective
G. Merrington, S. Fishwick and D. Brooke

Naturally occurring elements, which in some cases may be biologically essential but also potentially 
toxic, present significant problems to those charged with characterising and assessing ecological 
risk. The Environment Agency and Defra have developed a tiered ecological risk assessment
work for contaminated land, which has at Tier One, soil screening values for comparison with meas
ured field concentrations. For the soil screening values for metals to be ecologically relevant and 
effectively reflect potential risk, they must balance essentiality with potential toxicity. In addition, they 
must consider variations in ambient background concentrations, the use of ecotoxicological data 
developed in the laboratory – not in the field, and the influence of soil physico-chemical properties on 
metal availability.

Through the assessment of chemicals under the Existing Substances Regulations (Directive 98/8/
EC) programme at a European level, in particular for Zn, and the Voluntary Risk Assessments for Cu 
and Pb, research tools and techniques have been developed to address the environmental 
vance of total measured soil metal concentrations. The focus of this paper is upon the application 
and synthesis of the latest thinking from this metals research arena in a manner that attempts to 
meet both regulatory and stakeholder needs for soil screening values for ecological risk assessment.

Key words: metals, risk assessment, soil screening

Land Contamination & Reclamation, 14 (3), 673-684

DOI 10.2462/09670513.794

© 2007 EPP Publications Ltd

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