Screening-Level Ecological Risk Assessment Methods, Revision 3

Abstract

This document provides guidance for screening-level assessments of potential adverse impacts to ecological resources from release of environmental contaminants at the Los Alamos National Laboratory (LANL or the Laboratory). The methods presented are based on two objectives, namely: to provide a basis for reaching consensus with regulators, managers, and other interested parties on how to conduct screening-level ecological risk investigations at the Laboratory; and to provide guidance for ecological risk assessors under the Environmental Programs (EP) Directorate. This guidance promotes consistency, rigor, and defensibility in ecological screening investigations and in reporting those investigation results. The purpose of the screening assessment is to provide information to the risk managers so informed riskmanagement decisions can be made. This document provides examples of recommendations and possible risk-management strategies. This document describes the Laboratory-wide information needed for the screening-level ecological risk problem formulation, including the environmental setting, contaminant fate and transport, exposure pathways, and food webs. Screening assessments are performed on solid waste management units (SWMUs) 1 or areas of concern (AOCs); the area may also be a collection of SWMUs and/or AOCs in a watershed or some other aggregate. In this document, the term site is used broadly to include these different possibilities.