Risk Assessment & Ecology

Ecological Risk Assessment and Natural Resources
MACTEC has been involved in providing ecological assessment and ecological risk assessment (ERA) services since the mid-1980s, in support of site prioritization, remediation and risk management activities. Our experience includes work for the Department of Defense, Department of Energy, Department of the Interior and numerous private clients involving state Superfund sites, RCRA and CERCLA.

MACTEC has demonstrated considerable success integrating the concerns of both clients and regulators and negotiating approaches that streamline the ERA process. For one client, MACTEC provided a logically-based and scientifically defensible bridge between state, regional and US Environmental Protection Agency (EPA) national guidance, avoiding the formality of a baseline ecological risk assessment. We also have experience focusing ERAs on specific issues such as bioaccumulation and ecological monitoring, including focused annual fish collection and benthic macroinvertebrate surveys.

MACTEC’s support services include in-house laboratory testing for water chemistry and aquatic toxicity, and comprehensive services in field testing and data collection. Specific areas of our expertise include surface water (erosion and sedimentation studies, water quality surveys, permitting), wetland mitigation and design, aquatic assessment, protected species, cultural resources, toxicity testing, environmental planning, and geographic information systems (GIS) services.

We are experienced in conducting screening level assessments and quantitative risk assessments for aquatic, wetland and terrestrial ecosystems. We also provide ecological evaluations in support of NPDES permits, stormwater management, management of sediments for dredging projects, and management of petroleum and other contaminants in bay fringe and wetland areas.

Our biotoxicity laboratories are committed to providing the highest level of client services achievable to make each project a total success. These state-of-the-art facilities allow us to offer a turnkey approach to the analytical work that often accompanies risk assessments. Our labs specialize in effluent and sediment toxicity testing, toxicity identification/reduction studies, treatability studies, receiving waters impact studies, algal growth potential tests, long-term biochemical oxygen demand tests, and dredge material testing.

MACTEC's team of ecological and human health risk assessors, biologists, ecologists, hydrogeologists, geologists, toxicologists, statisticians, and engineers provide the following services:

• Bioassessment studies
• Biological monitoring
• Endangered species assessments
• Food web exposure modeling
• Natural resource damage assessments
• Tissue analysis
• Toxicity tests
• Wetland restoration plans
• Wetlands habitat receptor characterizations
• Macroinvertebrate community studies
• Small mammal population surveys

Data Acquisition
We work with clients, project managers, and data users to design programs based on the intended use of the data and to address project-specific regulatory and technical requirements. We use the EPA’s Data Quality Objectives process to design work, sampling and analysis plans, and to develop conceptual site models.

Data Management and Analysis Using GIS
Data stored in MACTEC's data management system can be directly accessed and manipulated using GIS. By integrating GIS with a data repository, MACTEC provides comprehensive, spatially referenced databases for projects in a broad range of service types. Project databases serve as a compendium for all historical data collected on a project.

Data Validation
MACTEC validates analytical results for organic and inorganic substances analyzed according to CLP, SW-846 and other standard and nonstandard methods, including those used for dioxins/furans, herbicides and explosives. We have validated data in the Department of Defense format, various EPA formats, and state formats for analytical programs.

Fate and Transport Modeling
We provide analytical and numerical modeling capabilities, including models ranging from simple analytical solutions to complex, three-dimensional numerical flow and transport models. We use over 140 computer models for fate and transport analyses of chemicals in air, soil, sediment, surface water, groundwater and biota.

Statistics
MACTEC applies statistical techniques that follow current EPA guidelines and create cost-effective compliance with regulatory requirements. Statistical techniques range from simple statistical summaries of analytical, geological, and hydrogeological data to parametric and nonparametric univariate and multivariate statistics such as analysis of variance, prediction limits, and tolerance limits.

Human Health Risk Assessment
MACTEC’s risk management capabilities integrate risk-based decision making into the many stages of a project, from the initial negotiation of a risk strategy and contamination assessment through the optimization of land reuse and rehabilitation. Risk management decisions should consider a wide variety of issues including environmental, regulatory, social, political, technical and financial factors. Our risk management group provides expertise in all project phases including:

• Planning: During the planning phase, the regulatory status of a property and any site-specific risk assessment guidance is identified. Participation in the planning phase allows MACTEC to identify data needs and to evaluate what types of field investigations are warranted. Acquiring this information in the planning phase results in significant cost and time savings as the project progresses.
• Investigation: MACTEC then uses the information obtained during the planning phase to evaluate the potentially complete exposure pathways and potentially exposed receptors. A focused sampling and analysis plan is then developed that ensures the collection of data appropriate for risk assessment.
• Reporting: During the risk assessment, MACTEC uses realistic land use projections to estimate the degree of exposure for each potential receptor population. Exposure estimates are compared to toxicity benchmarks to characterize risk for each receptor population. If risk estimates are within acceptable bounds, no corrective action is necessary. If risk estimates exceed acceptable bounds, MACTEC then assists clients in evaluating remedial alternatives, from exposure controls to removal and/or stabilization of site contamination.

MACTEC’S human health risk assessors are in the forefront of this evolving field and are actively involved in the development of risk assessment guidance, including the ASTM Risk-Based Corrective Action Standards. In recent years, MACTEC has given presentations at several national conferences on site-specific exposure assessments and ecological risk assessment.

Specific areas of MACTEC’s expertise include the following:

• Baseline risk, toxicity, exposure and liability assessments
• Brownfield redevelopment
• CERCLA/Superfund, RCRA, SARA, California's Risk Management and Prevention Program, Safe Drinking Water and Toxic Enforcement Act, Air Toxic "Hot Spots" Information and Assessment Act, etc.
• Hazard abatement, including air and noise monitoring, evaluation of potential exposures, and abatement recommendations
• Prioritization of large multisite facilities such as Base Realignment and Closure sites and ammunition plants
• Risk-based remediation strategies, health-based remediation goals, and emergency preparedness and contingency plans
• Site-specific exposure scenarios to limit cleanup costs
• Toxicological and safety examinations of new and existing products
• Hexavalent chromium (allergic contact dermatitis)
• Inorganics and metals
• Manufactured gas plant site residuals
• PAHs, VOCs
• PCBs, dioxins/furans
• Petroleum release sites
• Radionuclides
• Soils, groundwater, indoor air
• Surface water, sediments, fish consumption