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Site Investigation
Site investigations are critical to effectively evaluate and correct environmental impacts whether associated with a former underground storage tank or a Superfund site. Sites can be evaluated to characterize conditions and impacts in advance of evaluating and implementing remedial options. Alternatively, investigations can be completed concurrently with implementation of remedial measures by observing the effects of remediation on site conditions.
Objectives and needs for which site investigations are typically performed can include:
- evaluating sources of and identifying parties responsible for environmental contamination;
- characterizing the extent and magnitude of environmental contamination;
- assessing potential and likely pathways for migration of contamination;
- developing data for use in human health and environmental risk assessment;
- determining the need for and scope of remedial action;
- obtaining data required for evaluation, selection, and design of remedial alternatives;
- evaluating regulatory compliance; and
- supporting technical expert analyses and opinions in litigation matters.
Environmental media typically evaluated during site investigations include ground water, surface water, soil, sediment, soil gas, and air. Selection of appropriate investigation methods; types, locations, and
number of samples; laboratory analytical methods; and data interpretation techniques and tools is critical to the completion of investigations that meet client objectives.
Approach
The initial step in the investigation process is to identify the data needed to meet client objectives based upon an analysis of existing information and client and regulatory requirements. To maximize investigation efficiency, GeoInsight typically reviews data in regulatory and municipal files,
reviews reports by prior investigators and federal or state agencies,
reviews site surveys, and conducts interviews prior to designing the investigation. This background data review ensures that the work performed is focused only on those issues that are pertinent to the site and that are unresolved or incompletely characterized.
Methods
GeoInsight is experienced with a wide range of investigative methods and tools that are suitable for varying levels of complexity in site conditions and project objectives. These methods and tools include:
- installing and sampling an environmental monitoring network of wells and sampling stations or using an existing network;
- testing environmental media in the field using portable analytical equipment;
- evaluating aquifer characteristics through single well recovery tests and pumping
tests;
- geophysical surveys to identify potential migration pathways and confirm the suitability of monitoring network design;
- evaluating the presence of non-aqueous phase liquids;
- performing an analysis of contaminant migration in fractured bedrock;
- computer modeling of contaminant transport and fate to predict potential impacts on receptors and the performance of remedial options; and
- testing the effectiveness of remedial alternatives at the bench or pilot scale.
The end result of a site investigation is the development of a conceptual site model that consists of a three-dimensional understanding of contaminant sources, release mechanisms, and contaminant fate and transport mechanisms. Through this understanding of the site, GeoInsight can evaluate current and foreseeable risks to human health and the environment and assist our clients in making decisions on risk-reduction measures, if needed.
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