Lichen on fractured diabase boulder in the Sourland Mountain Nature Preserve - Hunterdon County, NJ

Too often, easy and effective solutions for environmental issues are not readily apparent.  In these situations, we believe the best answers are found with fresh thinking:  thoroughly analyzing and understanding client concerns, technical and regulatory issues.  Unfortunately, this basic process of asking and answering questions can be short-circuited when important decisions are made based upon incomplete information or incorrect assumptions.  Princeton Geoscience is diligent in avoiding the tendency to "force-fit" a project within the bounds of previous work experience,  easy regulatory acceptance and readily available technologies.  Though quite a few projects do call for self-evident, tried and true approaches, we find that an equal number are served best with creative thinking and new ideas.  Several unique strategies and new ideas we've developed are described below.

Road Salting as a Cause of Chloroform in Groundwater?  After delineating a plume of chloroform contaminated groundwater to its origin at the edge of a parking lot and finding no evidence of spills or other conventionally considered sources, Princeton Geoscience performed a literature review to assess alternative sources.  We learned that in recent years, the traditional view of chloride and other halide ions as essentially inert substances in groundwater has been challenged by field research in natural systems.  In fact, halide ions are part of a complex biogeochemical cycle, with natural production of organohalogens as one effect.  Naturally produced chloroform, for example, has been documented at concentrations as high as 2 ug/L in pristine forest environments where low levels of chloride in precipitation interact with organic carbon in the soil.  Chloroform is one of the most ubiquitous volatile organic compounds in groundwater and the sources of impact are often not well documented.  Because chloroform concentrations in groundwater at the subject site were high (up to 110 ug/L), we considered a purely natural origin unlikely.  However, we noted that the highest chloroform concentrations occurred at the downgradient edge of the parking lot, where salt-laced deicing melt waters run off to adjacent soil.  We determined that the runoff would create an abundance of salt-derived chloride ions in the soil, possibly enhancing natural chloroform formation processes.  Subsequently, we reviewed the idea with researchers from the University of Linkopping, Sweden, ultimately developing a novel understanding of the source and a practical remedial approach that was accepted by NJDEP.  Presently, Princeton Geoscience is funding and participating in several studies of natural and enhanced formation of chloroform and other volatile organic compounds in groundwater. (more info)

Dogwood tree in the Sourland Mountain Nature Preserve - Hunterdon County, NJPassive Remedy for Nitrogen Compounds in Groundwater  Following initial work by the property owner under the New Jersey Pollutant Discharge Elimination System (NJPDES) program, Princeton Geoscience delineated the extent of nitrate- and ammonia-impacted groundwater downgradient of an abandoned septic system.  The delineation and NJPDES monitoring results indicated the presence of an ongoing source of groundwater impact, in this case, ammonium ions sorbed to the soil matrix in the vadose zone and saturated zone beneath the abandoned leachfield.  Based on the groundwater concentrations of nitrate and ammonia and the proximity of the downgradient property boundary and nearby wetlands, some form of source reduction was considered a prerequisite to implementing a monitored natural attenuation program.   Due to various physical constraints, source excavation was ruled out, as were strategies requiring hydraulic containment.  Nitrogen compounds, principally nitrate, nitrite and ammonia, are among the most common groundwater contaminants in rural areas, where septic systems and agricultural activities are major sources.  Although the chemistry of the nitrogen cycle and processes for above-ground treatment are well understood through many years of experience in the wastewater treatment industry, that knowledge and experience has not been extensively employed in the remediation of underground sources, such as abandoned septic systems.  Princeton Geoscience developed and evaluated through bench-scale and field pilot testing, a two-stage, in-situ bioremediation strategy which utilizes gravity flow through the existing septic field piping as its only active component.  The strategy was approved by NJDEP and Princeton Geoscience is currently performing a pre-design study to assess flow requirements in the remedial design.  (more info)

RCRA Corrective Action - Streamlined and Sensible  A large solvent recycling company entered the RCRA Corrective Action program following issuance of a HSWA Permit.  Despite comments the property owner provided after reviewing the draft permit, the issued permit contained detailed and prescriptive requirements for investigation of various environmental media, submittal of draft and final versions of work plans and reports for multiple phases of investigative activity.  In addition, the permit specified numerous supposedly discrete site areas for separate investigation and reporting which were in fact more or less continuous with one another.  In short, the permit-required approach might have resulted in problems common to many Corrective Action cases:  onerous investigative requirements, confused delineation from one area proceeding into another, non-productive paperwork and generally slow, expensive and inefficient progress through the program.  Because such outcomes are not the goal of the Corrective Action program and are inconsistent with the RCRA Cleanup Reforms of 1999 and 2001, Princeton Geoscience proposed an alternate, streamlined approach to expedite the site characterization, which was accepted by USEPA Region 2 and NJDEP.  Under the revised approach, a site-wide rather than area by area investigative approach is being followed, and reporting for the the investigative work will be consolidated into a single document.  Interim communications are carried out in an informal Rocks and rill along the Stony Brook - Princeton Township, NJbut efficient way via e-mail and through submittal of brief quarterly progress reports.  Information from investigations on adjacent sites has been used extensively to develop the conceptual site model and to satisfy specific requirements under the Corrective Action program.  Princeton Geoscience has identified collaborative efforts by which the owners of the subject site and adjacent properties may most cost-effectively remediate groundwater contamination originating on their respective sites.  Based on the progress of the Corrective Action work to date, the property owner demonstrated achievement of goals for Environmental Indicators (EIs).  (more info)

Trace Metals Characterization in Glauconitic Coastal Plain Soil and Associated Groundwater  Princeton Geoscience performed an extensive soil and groundwater remedial investigation at a site located in the New Jersey Coastal Plain.  During the early stages of the project, a background study identified natural arsenic concentrations in soil at concentrations as high as 100 mg/kg.  Research indicated that the arsenic was associated with glauconite, a mineral constituent of the soil matrix, and NJDEP accepted that the soil concentrations of arsenic were of natural origin.  Later in the project, arsenic and several other trace metals, including lead, chromium and beryllium, plus aluminum, iron and manganese were detected in groundwater samples, generally with the highest concentrations noted at downgradient locations.  Because the soil of the aquifer matrix was known to contain trace metals, it was evident to us that the elevated metals concentrations in groundwater samples resulted mainly from turbidity introduced into the wells during purging.  When traditional techniques (i.e., low-flow purging, redevelopment of the wells) failed to produce low-turbidity samples, Princeton Geoscience developed other specialized techniques to obtain representative characterization of natural vs. facility-related groundwater impacts.  Based on results of these activities and a statistical comparison to published ranges of metal concentrations in New Jersey glauconitic soils, NJDEP conceded that concentrations of aluminum, iron and manganese were likely of natural origin, but maintained that the trace metal detections were of indeterminate or discharge related origin.  Princeton Geoscience then compared groundwater concentrations of the trace metals at the site to concentrations of the metals NJDEP had acknowledged were of natural origin and found a moderate to strong correlation for each of the trace metals in question.  Although NJDEP has not revised its statement with respect to the trace metals in groundwater, no remediation has been required to address this issue and Princeton Geoscience has indicated an intention not to include metals as groundwater contaminants in the Classification Exception Area information to be submitted for this site. (more info)

Geologic Characterization to Reduce Natural Radioactivity in a Groundwater Supply  Princeton Geoscience evaluated the source of radioactivity in the water supply of a condominium development in northwestern New Jersey and recommended alternatives for mitigation of the problem.  Groundwater withdrawn from the water supply system exhibited radium-(226+228) and gross alpha activity in excess of the federal Maximum Contaminant Limit (MCL) and NJDEP required correction of the violation.  The source evaluation consisted of reviewing published geologic maps of the area, determining well construction and pumping schedule, performing a site inspection and consulting with the New Jersey Geological Survey.  We determined that several geologic conditions may contribute radioactivity to groundwater, including radioactive minerals associated with certain bedrock units at the site and faults and other rock discontinuities where precipitation and rock-mass volume reduction may cause concentration radioactive minerals.  We recommended three options for providing an alternate supply, including geophysical assessment and alteration of the existing well, installation of a new bedrock well in a deeper geologic formation exhibiting lower radioactivity and installation of a shallow, high-yield well in unconsolidated glacial deposits.  (more info)


On September 25, 2007, Princeton Geoscience presented a paper titled, "Geology Matters: Updating a Bedrock Ground Water Remedy at a New Jersey Site in the Newark Basin" at the U.S. EPA / National Ground Water Association Fractured Rock Conference in Portland, ME.  The subjects discussed included changes planned to optimize a pump and treat groundwater remedy initiated in the early 1980s.  Key aspects involved in the re-evaluation were the presence of DNAPLs, flow control along bedding oriented fractures in the Passaic Formation, and positioning of the extraction wells relative to bedrock structure. The study emphasized the importance of 1) establishing an accurate conceptual site model and 2) periodically reviewing remedy performance in light of new understandings and development in science and technology.