Portfolio | Risk Assessment

Tetra Tech has performed hundreds of human health and ecological risk assessments involving hazardous substances at National Priorities List (NPL) and non-NPL sites for industrial and government clients. These projects have led to the development of tools for calculating risk and cleanup goals following U.S. EPA and State of California Department of Toxic Substance Control protocols. Tetra Tech performs risk assessments using realistic exposure pathways and parameters that lead to reduced site cleanup costs.

Predictive Ecological Risk Assessments for Edwards Air Force Base

Edwards Air Force Base (EAFB) is located in the western Mojave Desert and supports testing of manned and unmanned aircraft and aerospace vehicles, advanced flight testing and training, large and small rocket engine testing, and airborne weapons systems testing. ..... More >>

Hickam Air Force Base Military Housing

Tetra Tech developed site-specific human health-based environmental action levels (EALs) for pesticides detected beneath former military housing, which decreased the required cost of remediation by over $20 million dollars. Chlorinated pesticides, such as aldrin, dieldrin, and chlordane, were presen ..... More >>

Brownfield Redevelopment, Boulevards at South Bay

Tetra Tech is conducting the human health risk assessment at Carson, California, a 157 acre brownfield site. Restoration plans for this former municipal landfill involve development into multiple land uses, including residential, commercial, recreation, entertainment, big-box retail stores, restaura ..... More >>

Manufactured Gas Plant (MGP) Experience

Site Assessments: Tetra Tech successfully completed 18 site assessments for various MGP sites in California for Sempra Energy/The Gas Company. Our staff performed a thorough records search and document review of the sites, prepared detailed geological and hydrogeological studies, and conducte ..... More >>

Vandenberg Air Force Base Baseline Human Health and Ecological Risk Assessment, Lompoc, California

Tetra Tech conducted a Remedial Investigation/Feasibility Study (RI/FS) as part of the U.S. Air Force�s Installation Restoration Program (IRP) at Vandenberg AFB. The Base encompasses almost 98,400 acres and supports over 2,000 active and non-active facilities used for rocket launches, satellite trac ..... More >>

Port of Long Beach, Waste Disposal Facility

Tetra Tech conducted baseline risk assessments for three sites that operated as oil and gas waste disposal facilities between 1951 and 1971. The risk assessments evaluated potential exposures to PCBs, volatile PAHs, chlorinated hydrocarbons, organochlorine pesticides SVOCs and metals from soil and g ..... More >>

Background PAH Methodology to Support Remediation Decisions

Southern California: Tetra Tech staff implemented a statistically-based decision methodology for remediating elevated levels of carcinogenic polycyclic aromatic hydrocarbons (CPAHs) in soil to background levels at numerous former MGP sites and commercial/residential areas located near former ..... More >>

Development of Environmental Fate and Transport Models

Tetra Tech specializes in the development of advanced fate and transport models to predict chemical migration in the environment, which is a key component of conducting a defensible exposure/health risk assessment and allows for the most efficient allocation of resources in regard to sampling effort ..... More >>

Evaluating Potential Risks from Exposure to Total Petroleum Hydrocarbons (TPH)

Tetra Tech specializes in characterizing potential human exposures to total petroleum hydrocarbons (TPH). For client projects, Tetra Tech has used a number of recommended approaches for evaluating potential risks from TPH exposure including: the Department of Toxic Substances Control petroleum risk ..... More >>

Retention Basin Closures at Power Generating Stations in Southern California

Tetra Tech has been supporting RCRA closure activities for lined retention basins at numerous power generating stations in southern California since 2001. Closure demonstration is being used to limit or terminate environmental liability from previous releases of boiler cleaning solutions at the rete ..... More >>

Ventura Manufactured Gas Plant Site, Los Angeles, California

Following the successful pattern established at the former Aliso Street MGP, Tetra Tech has been successfully conducting environmental investigations, risk assessments, and soil removal actions at this approximately 9 acre site for the past 10 years by working in close coordination with the regulato ..... More >>