Site characterization activities provided by THWA are geared toward collecting the right amount of the right type of data necessary to fulfill the investigation’s predetermined objectives. This often includes evaluating the nature and extent of contamination and determining geochemical conditions to aid in our risk -based evaluation. Many of our competitors can provide the soil and groundwater sampling and analysis necessary to determine the nature and extent of contamination. We certainly have this ability. However, personnel from THWA have taken soil and groundwater sampling and site characterization to the next level. For example, in conjunction with personnel from the U.S. Air Force and the U.S. EPA, Todd Wiedemeier developed the sampling protocol required to fulfill the requirements for evaluating the geochemical conditions that lead to, or are caused by, natural attenuation. This sampling protocol is the keystone of the flagship U.S. EPA document titled Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater (Wiedemeier et al., 1998, EPA/600/R-98/128). Since the publication of this document several advancements have been made by personnel from THWA for the evaluation of both biologic and abiotic degradation mechanisms and enhanced bioremediation. These advancements are documented in recent or forthcoming documents being published bythe American Petroleum Institute (MTBE) and the Department of Energy (chlorinated solvents).
Personnel from THWA are familiar with all facets of site characterization required to provide the data necessary to define the chemical, physical, and biological characteristics of a site; evaluate the presence, type, and extent of contaminants; perform risk assessments; and satisfy regulatory agency concerns and thus reduce their level of involvement. In fact, personnel from THWA were instrumental in developing many of the site characterization techniques in use today, particularly those used to establish the geochemical environment at a particular site. Site characterization techniques may include, but are not limited to, land use and demographic surveys, soil gas surveys, borehole and monitoring well construction, ground and surface water sampling and analysis, soil and sediment sampling and analysis, and aquifer testing. Because THWA provides comprehensive services ranging from the initial site characterization through site closure, we are sensitive to the need to collect sufficient data during the characterization process to allow completion of all subsequent tasks without additional site characterization. Doing the job right the first time often results in our clients saving a significant amount of money. Every THWA site characterization project includes the development of a detailed sampling and analysis work plan, a health and safety plan, and a comprehensive quality assurance/quality control plan. These plans are developed around project-specific concerns and requirements for the types of data to be collected. The level of effort defined in the work plan is based on the amount of data required to adequately characterize the site and support our risk-based approach to remediation. THWA has experience in writing an implementing work plans for RCRA, CERCLA, and State and Local Agencies throughout the country.
THWA has site characterization experience at a wide variety of sites under the auspices of Federal (RCRA and CERCLA), State, and Local Agencies throughout the country. Sites evaluated by personnel from THWA include gasoline service stations, refineries, landfills, petroleum pipelines, chemical production facilities, dry cleaners, and military fire training areas.
Personnel from THWA were instrumental in developing the widely-used field protocols for determining the geochemical conditions at a site. These protocols were developed based on site characterization experience obtained from hundreds of sites across the country and around the world.
Knowledge of the prevailing geochemistry is important because the degradation of contaminants in the subsurface is strongly influenced by the prevailing geochemical conditions at a site. By knowing the geochemistry natural attenuation and other remedial alternatives can be evaluated in a cost effective manner and allow selection of the most cost-effective remedial alternative. In many cases natural attenuation may be sufficient to protect human health and the environment for all or part of a contaminant plume. This has resulted in the savings of hundreds of millions of dollars in unnecessary remediation costs.