Level of detail in ecological risk assessments

Ecological risk assessment (ERA) is an iterative process that can involve p roceeding through several tiers of assessment prior to obtaining results wi th acceptable uncertainty. The first tier (e,g,, screening-level risk asses sment (SLRA)) is typically conservative and serves to narrow the scope of t he assessment to the main issues of concern. The strategy for subsequent as sessment tiers (e,g., detailed level risk assessment (DLRA)) is dependent o n a number of factors and is difficult to prejudge. Consequently, while for mal prescriptive guidance may be useful for the SLRA, it would probably be constraining for DLRA and reduce the effectiveness of the risk assessment p rocess, This paper examines the level of detail required for SLRA and DLRA, Differences between the two include: type of information; levels of resour ces, conservatism and uncertainty; information used; range of substances of potential concern (SOPCs) and receptors considered; use of multiple lines of evidence; level of effects estimation; point versus probabilistic estima tes of exposure and effects. The appropriate level of detail for both types of risk assessment is described, but not prescribed. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.