Techical Peer Review/Expert Witness Services

In most cases, Geological Services Inc. Technical Peer Review and Expert Witness Services both involve comprehensive review of site characterization data collected by others in order to provide a fair and unbiased assessment of the nature of specific environmental impacts- how, when and where they occurred,  how well corrective actions have worked during the sites period of record, and how they can be expected to work in the future. Geological Services staff have provided expert witness services including testimony, legal brief preparation and presentations in cases ranging from local and regional commissions to district courts, and in one case, the Supreme Court of West Virginia.

Statistical Analyses - Cause and Effect Evaluation: Here, Geological Services Inc. provides detailed evaluation involving multiple regression, time series analyses and multivariate correlation evaluation to determine the root causes of contaminant concentration variation. In the case shown, site contaminant concentrations were shown to be clearly correlated with natural variations in hydrologic recharge (rainfall and snowmelt events) instead of with new contaminant releases at the site as had been previous thought. That realization resulted in savings of several hundreds of thousands of dollars that had been requested to determine the source of the new release and its containment.

Conceptual Model Development: Perhaps the single most important element of the site corrective action process, conceptual model development involes detailed integration of all site data including historic water levels, soil and groundwater contaminant concentrations, aquifer testing results, and well log measurements into a cohesive picture of the site. In the case shown, what had been previously viewed as a single point of release and accumulation was determined to be in fact two separate areas associated with the heterogeneities of the karst bedrock site subsurface -greatly affecting the path of subsequent site corrective actions leading to site closure.

Contaminant Trend Analyses: Based on measured contaminant levels over time, Geological Services, Inc. fits mathematical regression equations to site data and derives a mathematical equation allowing prediction of average site contaminant levels at any point in time. Prediction of contaminant levels allows determination of previous impacts, as well as future impacts with a high degree of accuracy as defined by statistical prediction limits (up to 99.7%) which address the possible variation of site contaminant levels based on previous site history.  Prediction of contaminant levels allows estimation of the time to site closure, which in turn allows a determination of site closure budget and the efficacy of site remedial efforts to date.

Contaminant Plume Simulation: Using all other available site data, including trend and statistical analyses and conceptual model development, Geological Services Inc. constructs calibrated numerical models that can be used for any number of applications, including the following:

  • Source area/responsible party determination
  • Delineation and identification of affected properties, either past, current or future
  • Determination of the magnitude and timing of potential impacts
  • Identification of affected or potentially affected parties
  • Identification and/or prediction of contaminant levels at any point withing the body of the plume