Soil and Groundwater Investigation Services

EC&A provides a full range of geological, hydrogeological, engineering, environmental management and contracting services for investigation and cleanup of hazardous substances releases. Our services are most commonly employed to investigate and remediate releases of petroleum hydrocarbons from underground fuel storage tanks (USTs), or waste dry cleaning solvents that have impacted soil and groundwater as a result of long-term disposal onto the ground surface or escape through breaches in sanitary sewer lines. For unknown substances, we collect samples, have them analyzed at an appropriate laboratory and report the results with our conclusions and recommendations. Some of the investigation and remediation services EC&A provides are:

Phase I Environmental Site Assessment (ESA)

This type of investigation is generally intended to establish whether a site has been, or is likely to have been impacted by hazardous materials. It should also identify the types of hazardous materials that may have impacted the site. If a REC is identified by the ESA, a Phase II investigation may be remediation, to establish whether there has been an impact to soil and/or groundwater.

Preliminary Site Investigation (PSI – Phase II)

This initial investigation of soil and groundwater conditions at a site, is intended to establish whether the property has been impacted by hazardous materials, and to identify the types of materials. The investigation commonly involves drilling borings, logging soil types and conditions, collecting samples of soil and groundwater, laboratory analyses of the samples, evaluation of the data and preparation of a report of findings with our conclusions and recommendations. It may instead, or additionally, involve advancing devices that provide logs of soil parameters and allows for the collection of samples of groundwater. In some instances, groundwater monitoring wells may be installed to allow for periodic collection of samples and calculation of groundwater flow-direction and gradient.

If contaminants are identified in a sample(s), the local regulatory agency may require further investigation and cleanup. If groundwater has been impacted, the Regional Water Quality Control Board will direct and oversee the investigation and cleanup.

Client and Regulatory Agency Communications/Negotiations

EC&A staff maintain open lines of communication with clients and regulatory agency personnel throughout the project. We understand that our science is evolving and some clients may not be familiar with the terminology. Therefore, we make frequent communication a priority. Because conditions are different at every site and regulatory agency guidelines change and are not the same in every region, negotiating investigation and cleanup issues is commonplace.

Soil and Groundwater Investigation and Contaminant Delineation (also Phase II)

When a Preliminary Site Investigation (PSI) does not completely delineate the extent of migration of the contaminant(s) released to a site, a more comprehensive soil and groundwater investigation is performed. The goals of this investigation are to evaluate subsurface soil and groundwater conditions farther from the area of the release, and establish the lateral and vertical extent of migration of the contaminant(s). The results of this investigation are intended to provide the data needed to select an appropriate remediation alternative.

For geologically/hydrogeologically complex sites and/or where contaminants are widespread, completion of Phase II may require several field investigations, each providing the data needed to design the scope of work for the next, with the ultimate goal of completely defining the lateral and vertical extent of migration of the contaminnts and providing the data needed to select the appropriate method of remediation.

Soil and Groundwater Remediation (Cleanup)

Soil and/or groundwater remediation may be performed in many ways, including sometimes just letting nature take its course. It is EC&A’s task to identify a method(s) that serves the client’s needs and meets regulatory agency cleanup requirements. Commonly, an appropriate and cost-effective remediation alternative is identified by performing a Feasibility Study (FS). A Corrective Action Plan (CAP) is then prepared, providing details of implementation and monitoring of the selected remediation alternative. If greater details of the CAP are needed, a Remedial Action Plan (RAP) is prepared for the local/regional regulatory agency, and if applicable the State UST Cleanup Fund, to review and approve. EC&A’s costs for investigative and cleanup services are consistently within State UST Cleanup Fund guidelines, thus allowing our clients that are on the State Fund, to receive full reimbursement for our costs.

Examples of soil remediation alternatives:

  • Passive in-situ bioremediation
  • Active in-situ bioremediation
  • Biosparging
  • Excavation, hauling and disposal
  • Soil vapor extraction with/without air sparging
  • Encapsulation
  • Ozone micro-sparging with/without hydrogen peroxide
  • Cheeze Whey injection

Examples of groundwater remediation alternatives:

  • Passive in-situ bioremediation
  • Active in-situ bioremdiation
  • Biosparging
  • Soil vapor extraction with/without air sparging
  • Pump and treat
  • Ozone micro-sparging with/without hydrogen peroxide
  • Cheeze Whey injection

There are a number of other methods of soil and groundwater remediation that are evaluated for a site if conditions appear to warrant their consideration.

Risk Assessment (RA)

A baseline RA may be performed to help establish whether additional response action is necessary at a site, to modify preliminary remediation goals, help support selection of the “no-action” remedial alternative, where appropriate, and document the magnitude of risk at a site, and the primary causes of that risk.

The baseline risk assessment is an analysis of the potential adverse health effects (current or future) caused by hazardous substance releases from a site in the absence of any actions to control or mitigate these releases (i.e., under an assumption of no action). The baseline risk assessment contributes to the site characterization and subsequent development, evaluation, and selection of appropriate response alternatives.

Baseline risk assessments are site-specific and therefore may vary in both detail and the extent to which qualitative and quantitative analyses are used, depending on the complexity and particular circumstances of the site, as well as the availability of applicable or relevant and appropriate requirements (ARARs) and other criteria, advisories, and guidance. After an initial planning stage, there are four steps in the baseline risk assessment process: data collection and analysis; exposure assessment; toxicity assessment; and risk characterization.

State GeoTracker Internet Database Formatting/Submittal

On January 1, 2005 the State Water Board adopted regulations that require electronic submittal of information (ESI) acquired during soil and groundwater investigations at underground storage tank (UST) sites and at non-UST cleanup programs, including Spills-Leaks-Investigations-Cleanups (SLIC) sites, Department of Defense sites (DOD), and Land Disposal programs. Among the required submittals are complete copies of reports, including a site map, the results of both land and GPS surveys of boring and monitoring well locations, and the results of analyses of soil and groundwater samples from the site, in PDF format. EC&A acquires, formats and submits the required data.

Global Positioning System (GPS) Surveys

The State Water Board requires that the locations of borings, monitoring wells and other points where samples for laboratory analyses have been acquired on a site, to be located to sub-meter accuracy by a GPS survey, and the data submitted to the State GeoTracker Internet Database. EC&A uses a Trimble GPS unit to acquire the necessary data an then we submit it as required.