Evidence and Judgement in Environmental Risk Assessment: The Case of the UK Contaminated Land Regime

• Main Author: Evans, Jens C. R.
• Published: Oxford Brookes University 2007
• Subjects: 711
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490524

Risk has emerged as a dominant decision-making paradigm in UK environmental regulation. Much of its appeal rests on the assumption that it provides an objective way of judging the significance of environmental problems so that defensible and proportionate regulatory action can be taken. However, this assumption is challenged in the risk literature. Consideration of the risk assessment process shows that it requires methodological judgements and there is debate whether these are made on objective (scientific) or SUbjective grounds. The UK contaminated land regime provides an ideal case study to examine the way that these methodological judgements are made. The regime is explicitly risk-based, with decisions about the significance of contaminated land risks made in theory solely on the basis of technical risk assessments. This research examines the factors that influence key methodological jUdgements in contaminated land risk assessment and explores the extent to which they affect subsequent decisions about the significance of contaminated land risks. A survey of UK risk assessment practitioners shows that many of them consider risk assessment to be at least partly SUbjective, although opinions vary on the extent to which specific methodological steps are subjective. Interviews with risk assessors conclude that personal, commercial, technical and organisational factors influence their methodological choices. Similar interviews with local authority officers conclude that their ability to critically evaluate and influence these judgements is diminished by variable expertise, limited resources, inadequate regulatory guidance and low transparency of reporting. Cumulatively, these factors have a material bearing on the findings of an assessment. It is concluded that current contaminated land risk assessment is a social process in which non-scientific considerations significantly influence key judgements. It follows that risk assessment does not actually provide an objective basis for deciding the acceptability of contaminated land risks. This conclusion. has a wider significance for the use of risk assessment in environmental regulation.