Preliminary ecotoxicity assessment thresholds: Setting screening values for terrestrial systems

How does one address the question of what level of environmental contamination causes adverse effects in plants and wildlife based solely on information from the ecotoxicology literature? One is confronted with a database derived from studies conducted in different laboratories, with different protocols, on different species that address different toxicity endpoints. Rarely will this information be directly applicable to the species of interest. How then are priorities set to sort the literature data in order of relevance to needs? Using decision analysis theory in an analytical hierarchy procedure the authors queried a panel of experts to define which components of a study make it more or less applicable to determining toxicity thresholds for organisms in their natural environment. A questionnaire guided them through a series of pairwise comparisons that enabled them to rank the importance of study duration, endpoint, and other reported variables. Each study from the literature can then be ranked according to the relative weights given to each of the categories and its usefulness determined for setting threshold values for a species of interest.