About Us
Representative Client List
|
Environmental Assessment
Select a Link for More Information
Ground-Penetrating Radar (GPR)Ground-Penetrating Radar can be used to map man-made features, such as tanks, drums or infrastructure; or variations in soil or bedrock, such as stratigraphic changes or voids. Ground-Penetrating Radar provides a continuous profile of the subsurface by transmitting a radio frequency signal into the ground through an antenna as it is moved along the surface, then measuring variations in the reflected radar waves. Shallow subsurface materials with contrasting electrical properties, such as a drum/soil interface or bedrock/soil contact, are often apparent in GPR cross-sectional profiles. MagnetometryThe advantage of a Magnetometry survey is its extreme sensitivity to the presence of buried ferrous materials, such as steel drums, tanks, vehicles, piping or other infrastructure. Magnetometer screening can be done at a walking pace on open land, making this technique relatively cost effective. Electromagnetic (EM) Induction (Terrain Conductivity)This technique measures the electrical conductivity of subsurface soil and bedrock, and is sensitive to ferrous and non-ferrous materials. Often used for detection of buried drums, tanks and infrastructure, EM techniques can also be used to detect contaminant plumes, determine lithology, and identify the margin of landfills. Direct-Current (DC) ResistivityContaminant plumes, burial sites, and geohydrologic conditions can be inferred by mapping lateral changes in subsurface electrical properties via DC resistivity soundings. Seismic RefractionSeismic Refraction techniques can be used to determine the depth and thickness of geologic strata. When used in conjunction with soil boring and well data, seismic measurements can allow extrapolation over a larger area, reducing the cost of boring programs and monitoring well networks. Seismic waves induced at the surface travel downward and are bent or "refracted" at the interface of differing layers. By using an array of geophones to measure the wave travel time, we infer the seismic velocity of each layer, which is directly related to its properties, such as density and hardness. On properties contaminated with volatile chemicals, such as fuels and solvents, vapors can potentially migrate from the water table, through the soil, and into buildings. Because recent studies show that the potential for vapor intrusion into buildings has been underestimated in the past, most contaminated sites must undergo testing to determine whether a vapor intrusion pathway exists.
In New York, if groundwater within 100 feet of a building is contaminated with volatile organic compounds (VOCs), then sub-slab sampling and indoor air sampling must be completed for that building. Conrad Geoscience performs vapor intrusion sampling and evaluation. A complicating factor in such evaluations is the potential for target compounds to be present inside the building from usage of fuels, cleaning agents, and other common sources of VOCs. A further complication is that differences in building construction and ventilation can make indoor air sample results misleading. For these reasons, vapor intrusion evaluations include both indoor air sampling and sub-slab vapor sampling. Ambient outdoor air is also sampled. To produce reliable results, the sample collection process must be carefully planned and executed using specialized tools and materials. For information about the U.S. Environmental Protection Agency vapor intrusion policy: Click Here For information about New York State’s vapor intrusion policy: Click Here Each year, the New York State Department of Environmental Conservation receives more than 16,000 reports of petroleum and chemical spills. State and federal law requires that the responsible party take steps to contain and clean up such spills, and, when necessary, to investigate potential impacts to soil and groundwater.
Conrad Geoscience has performed hundreds of spill investigations to delineate the severity and extent of soil and groundwater contamination, and to determine what types of corrective action are required in the aftermath of a spill. Throughout this process, Conrad Geoscience confers with regulatory agencies on behalf of the client. Spill assessments often include conventional approaches such as soil boring programs and monitoring well installation for collection of soil and groundwater samples. In cases where buried tanks, pipelines or containers must be located, we use non-invasive techniques, such as magnetometry and ground-penetrating radar. In cases where the source or extent of groundwater contamination is uncertain, we use non-invasive soil gas surveys to map contaminant plume geometry. In New York, the public can notify DEC of petroleum and chemical spills by calling the Spill Hotline: 1-800-457-7362 Federal agencies can be notified by calling the National Response Center: 1-800-424-8802 For more information about spill response in the State of New York: Click Here The NYSDEC maintains a registry of sites at which disposal of hazardous waste is known or suspected. Once registered, responsible parties (owners, operators or transporters) are obligated to conduct the following steps:
Following are a few recent examples:Hazardous Waste SitesBeekman Highway Garage Client: Town of Beekman Location: Beekman, NY Conrad Geoscience designed a Remedial Investigation (RI) that combined geophysical and soil gas surveys with conventional soil and groundwater sampling to pinpoint the source of a chlorinated solvent plume on the Town’s 10-acre Highway Department property. Conrad Geoscience designed and completed the remedial program, which included source removal and monitoring of natural attenuation via a network of on-site monitoring wells and off-site residential wells. Circle M Wood Treating Corp. Client: Chelsea Industrial Park Location: Fishkill, NY Conrad Geoscience conducted a Remedial Investigation (RI) to determine the extent of heavy metal contamination in soil and groundwater at a former lumber treatment operation, followed by an evaluation of remedial alternatives (FS). The proposed remedy is to integrate construction of a low-permeability cap with site redevelopment. LIRR Electrical Substations Client: Dvirka & Bartilucci Engineers Location: Long Island, NY At 12 transformer stations operated by the Long Island Railroad, Conrad Geoscience located waste disposal dry wells using ground-penetrating radar and magnetometry, and traced associated piping using electromagnetic techniques. Conrad Geoscience personnel are proficient in a variety of subsurface characterization techniques. Situations and circumstances differ from site to site. Contaminant movement can be affected by soil and bedrock characteristics, properties of the product spilled, origin and timing of the release, seasonal changes, and many other factors. No two subsurface investigations are alike.
|
