Selection of Contaminants and Receptors of Concern for Ecological Risk Assessments Using the Paired Comparison Technique (PCT)

Abstract

A critical component of the ecological risk assessment process, identification of contaminants and receptors of concern, is currently lacking an objective, data-driven, broadly applicable methodology. The paired comparison technique (PCT) can be used to meet this need by providing a standardized technique for making these decisions. PCT condenses the decision-making process down to individual components and ultimately generates an objective ranking for each alternative based on pertinent attributes. Factors considered in the PCT may be selected and weighted via a formal consensus building process which can incorporate stakeholder concerns. Once factors have been selected and weighted, each alternative is ranked relative to each other alter native for each factor. Each alternative ranking for each factor is multiplied by the factor's weight and the weighted rankings are summed. These sums are then used to rank alternatives relative to one another. This ranking provides decision-makers with a semi quantitative basis for making final decisions, although the technique itself does not (and should not) actually make the decision. Several examples of the technique using actual Superfund site data are presented.