Environmental Risk Assessment

Overview

Working within Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource Conservation and Recovery Act (RCRA) regulatory requirements, SAIC has addressed impacts to human health as well as the biotic components of the nearshore environment located adjacent to freshwater, estuarine and marine sites.

Ecological Risk Assessment activities include assessment of the status of bottom-dwelling (benthic) species, chemical and microbial (bacterial indicators) contaminant exposure conditions in sediment, porewater and biota, and toxicity of sediment and water. These "lines of evidence" are used to draw conclusions about the likelihood of adverse impacts caused by site-related chemicals. Specialized testing procedures known as Toxicity Identification Evaluations (TIE) have been conducted at several sites to determine which contaminants (including natural constituents, like ammonia) are responsible for the toxicity.

SAIC also supports the RI/FS Program through development of site-specific Preliminary Remediation Goals (PRGs) which are numerical, site-specific chemical concentration thresholds for protection of aquatic, terrestrial, and human health to be achieved during remediation. A range of techniques have been utilized including expert knowledge, empirical or theoretical models, multivariate statistical techniques, and spatial overlay analysis to map the distribution, abundance, and seasonality of biological resources in relation to contaminant distribution. SAIC also conducts food-chain modeling to assess impacts on human health from consumption of fish containing chemical residues accumulated from in-place sediments as well as from activities such as dredged material disposal.