HETI offers site investigation services in several major areas:

	Cause and origin investigations to determine the history of events leading to a release and environmental contamination.
	Subsurface investigations, involving a variety of soil, ground water, and soil gas sampling techniques and geophysical surveys, to identify and delineate contaminant source areas and determine the extent and magnitude of environmental contamination.
	Forensic and fate-and-transport analyses to evaluate sources and predict impacts. These projects can include ground water flow and geochemical modeling.
	Evaluation of threats to, or impacts on, indoor air quality.

Typically, site investigations are focused on determining the extent of contamination. However, they are also used to support decisions regarding risk characterization and/or site remediation. HETI uses our extensive experience in risk management and site remediation to develop investigative work scopes that provide information necessary to evaluate and design cost-effective approaches to site closure.

HETI also performs a broad range of geological services, including studies in bedrock aquifer mapping, rock and soil categorization, aquifer pumping tests and other remedial design studies, and geophysical studies. Through contractual agreements with State-certified water and soil testing laboratories, HETI provides prompt turn-around service and maintains strict quality control.

Representative Projects *

Ground Water Modeling, Drinking Water Aquifer (Massachusetts) - HETI performed a site investigation in response to the observation of contamination in soil and ground water during an underground storage tank (UST) removal. HETI determined that a confined aquifer extended beneath the site, and that varied deposits above the aquifer acted as a confining bed. Because of the perceived threat to the nearby well field, regulatory authorities required that a ground water remediation system be installed. HETI used a screening-level model to provide a first-cut analysis as to whether a multi-well system would provide hydraulic control given the thin saturated thickness. When the results were positive, a full numerical aquifer simulation was performed using data from on-site and off-site monitoring wells. The simulation showed that a five-well system would provide hydraulic control of the plume. An extraction well system based on the model was designed by HETI and approved by regulators. To evaluate effects on the confined aquifer, HETI advanced a 60-foot boring into the confining layer. Hydraulic conductivity testing indicated a downward vertical hydraulic gradient. HETI performed analytical flow and transport modeling to estimate the flux of hydrocarbons through the confining layer. That flux was then compared to the yield of the municipal wells to evaluate potential impacts on potable water quality. HETI documented that the estimated impacts were negligible.

Environmental Forensics, Petroleum Age-Dating (Oregon) - In 2001, a major insurance carrier contracted HETI to review existing site data for an active marina on a river in Oregon for potential future litigation support. In operation since the 1930s, the facility contained one 4,000-gallon single-walled underground storage tank (UST) installed in 1971 (replacing an older tank with an unknown installation date) and one 10,000-gallon single-walled steel UST installed in 1981. In 1988, the marina's manager noticed a petroleum sheen on the river - attributed to a cracked elbow in the fuel line, located near the turbine pump for the 10,000-gallon UST, which was repaired. Six years later, the USTs were excavated and removed, and showed slight-to-moderate steel corrosion. Although no ground water or free product was at the bottom of the excavations, petroleum stained soil, with a noticeable petroleum product odor, was observed on the four sidewalls of both excavations. Approximately 100 cubic yards of contaminated soil were removed and treated off site. HETI conducted a forensic geochemical investigation to compare source fuel and lead isotope signatures obtained from on-site hydrocarbon contaminated soil analyses from soil samples collected from direct push borings in the vicinity of the removed USTs (the source area) and in the down gradient portion of the hydrocarbon plume. Hydrocarbon analysis by gas chromatography/mass spectrometry indicated gasoline and diesel fuel in seven of the ten analyzed soil samples. Lead isotope ratios for four soil samples were determined by thermal ion mass spectrometry. Based on these analyses, HETI concluded that, if commingling of hydrocarbons is considered, a mid-1970s age date is realized. Therefore, hydrocarbons in the toe of the plume may represent an earlier spill than the one being claimed.

Real Estate Transaction (Massachusetts) – A national restaurant chain purchased an industrial property at which significant contamination had been detected in soil and ground water. The property is listed as a disposal site by the Massachusetts Department of Environmental Protection. The company had subdivided the property – constructing a restaurant on one parcel and placing the other parcel for sale for commercial use. HETI was retained on behalf of a potential buyer, who had limited experience with contaminated real estate and was concerned about potential environmental liabilities. The seller made several offers including discounted price, limited site cleanup, and indemnification of the buyer. HETI reviewed the available site records and the technical and regulatory aspects of each offer and participated in meetings of the stakeholders and their legal counsel. With HETI’s assistance, favorable terms were negotiated and the sale was completed. HETI has continued to provide consulting services to the buyer during property development.

Scrap Metal Recycler (Pennsylvania) - Following the discovery of a white milky substance in the staging yard of a scrap recycler, HETI was called to investigate the origin of the substance and determine the reasonable and necessary response measures. HETI determined that the milky white substance was a hydrocarbon-based, emulsifying agent utilized by a metal fabricator that sourced scrap metal to the facility. Response measures to protect an adjacent sport-fishing stream were deemed appropriate; however, impacts from a secondary release were identified and excluded from the environmental claim, due to the fact that all parties were on notice of the problem after the initial release.

Surface Soil Sampling, Railroad, (California) - HETI performed surface soil sampling for a railroad agency, along a newly purchased railway easement, to evaluate background surface site conditions for total extractable petroleum hydrocarbons (TEPH), volatile organic compounds (VOCs), semi-VOCs, organochlorine pesticides and polychlorinated biphenyls (PCBs), and the California code of regulations (CCR) title 22 metals. The analytical results determined that all the compounds were less than the risk-based screening levels (RBSLs) for industrial/commercial uses. No further investigations were recommended.

* This is a brief description of selected Site Investigations completed by HETI. For a more complete discussion of our capabilities, please contact us for a copy of our Statement of Qualifications.