BJAAM Environmental will recommend risk assessment for selected sites where health and safety risk analysis provides a more feasible, less costly approach to remediation than subsurface treatment approaches. Recent trends in public policy have made risk assessment an advantageous option for many facility owners. It may be most desirable under the following conditions and circumstances:

• Contaminants are difficult to extract because of soil properties
• Structures or facilities overlie contaminated areas of the site
• Sites are permanently dedicated to commercial or industrial uses

Risk assessment is a regulatory approved solution to specific site contamination and has the potential to revise published maximum contaminant levels on a site-specific basis. It involves five steps:

1. Site Assessment -- chemical identification and delineation
2. Toxicity Evaluation -- evaluation of pathways through which chemicals may reach a point of human exposure
3. Exposure Evaluation -- site-specific, quantitative evaluation of the exposure levels and potential doses through air, water, and ingestion pathways
4. Risk Characterization -- a quantitative statement of dose/response relationships
5. Risk Management -- a summary of total risk and hazard to present and future human populations at the site

BJAAM currently recommends close consideration of risk assessment in instances when soil contamination is the principal concern at the site, where site factors make intrusive remediation difficult and very costly, and where the potential for collecting risk-based data as part of the site assessment is good. BJAAM Environmental has the experience to advise clients as to whether a full risk analysis would be beneficial and likely to produce a cost-effective remediation of the site.

Ground Water Flow and Contaminant Transport Modeling

BJAAM has brought together a multi-disciplinary staff of scientists with expertise in hydrogeology, geochemistry, physics, computer science, statistics, regulations, and toxicology who use a variety of well-verified and validated codes coupled with state-of-the-art pre- and post-processors to produce cost-effective solutions to environmental problems. In addition, BJAAM modelers work closely with other staff members to design field and laboratory programs for the collection of modeling data, produce technically sound and cost-effective remediation alternatives, and evaluate the impacts of model development on potential regulatory negotiations.

BJAAM scientists use a variety of one-, two-, and three-dimensional models to simulate both saturated and unsaturated ground water flow for studies of hydrologic impact, ground water/surface water interaction, aquifer test analysis, and the design and implementation of remediation alternatives. In the area of geochemical evaluations, BJAAM's staff provides expertise in chemical natural attenuation, contaminant transport, predicted contaminant loading and plume migration, geochemical fingerprinting, and leaching studies.