Laurel Environmental Associates, Ltd

About Soil and Groundwater Testing Services

Soil and Groundwater Testing Case Study

Study 1:
A property in Sag Harbor, New York was suspected of having petroleum contamination due to former use and close proximity to a former Major Oil Storage Facility (MOSF).   LAUREL's principal supervised the installation of three groundwater monitoring wells.  By using field screening techniques, such as the Photoionization Detector (PID), visual and olfactory methods, obviously contaminated soil samples were collected for analysis at a New York State Department of Health (NYSDOH) certified laboratory.  The monitoring wells were purged and developed until turbidity was less than 50 ntus at which point groundwater samples were obtained and also taken to the laboratory for analysis.
phase 1 sample report cover-click to see full report (pdf)
phase 1 sample report cover-
click to see full report (pdf)

The analysis indicated gasoline and fuel oil contamination in soils at a depth of two to seven feet below grade.  Based on the laboratory analysis of the groundwater samples, it was apparent that the contamination did not extend into the groundwater.  It appeared that the light non-aqueous phase liquid (LNAPL) was riding atop a fluctuating water table and adhering/adsorbing onto the soil particles.

The monitoring wells were surveyed using a known datum, and depth-to-water measurements were taken. Using this data, hydraulic flow gradient (groundwater flow) maps were produced, showing flow patterns at  high and low tides.  The maps also indicated that due to an already low hydraulic gradient, it was further diminished at times by tidal fluctuations.  This proved that there was a distinct possibility for contamination to travel via dispersion on the water table from the nearby MOSF and was not from an on-site source.

Research of records at the NYSDEC also confirmed that large amounts of fuel had been spilled at the MOSF.  Prior to a remedial effort, our consultants detected as much as three feet of product riding atop the water table on this site.  Thousands of yards of petroleum-contaminated soils were subsequently removed from the MOSF.

Study 2:
LAUREL’s subsidiary Ep2, is fortunate to own and operate its own Geoprobe and sampling equipment.  Our experienced staff collected discrete soil and groundwater samples at a former chemical storage and sales facility in Farmingdale, New York using the Geoprobe.  geoprobeA prior environmental investigation had demonstrated that Perchloroethene (PCE or PERC) contamination was present in shallow soils at the property.  However, the vertical and horizontal extent of contamination had not been fully determined.

To delineate soil contamination, sample cores were collected in a radial pattern emanating from the “Hot Zone”.   Based upon field screening, for volatile organic compounds with a Photoionization Detector, samples were submitted from multiple depths for laboratory analysis to determine the width and breadth of contamination.  The results showed that the majority of contamination did not extend beyond a confining clay layer at four feet below grade.  Furthermore, laboratory analysis of groundwater samples from hydraulically up and down-gradient locations did not indicate elevated levels of PCE contamination were present.  Due to the lack permeability of clay, the clay layer acted as a natural barrier and prohibited the contamination from leaching down into the groundwater.  This was further supported by laboratory data, and an appropriate remediation plan was formulated and carried out to regulatory and client satisfaction.

Laurel Environmental Associates, Ltd
53 West Hills Road, Huntington Station, NY 11746 | t. 800-453-0578 | f. 631-427-5323
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