MERIT ENGINEERING was retained by American Property Development (APD) of Bellevue, WA to conduct a Phase I Environmental Site Assessment on a property previously investigated for possible contamination due to an adjacently located closed landfill. The property consisted of a vacant 29.2-acre lot that was primarily used for farming in recent past. However, due to the close proximity of the adjacent landfill, a complete soil and groundwater assessment of the property had been ordered by the city to determine if the landfill was causing contamination to the property. During these investigations, it was found that the property contained elevated amounts of polycyclic aromatic hydrocarbons (PAH) in some soil samples analyzed at concentrations exceeding the MTCA Method A Soil Cleanup Standards. However, analytical methods used on the soil samples used high detection limits, making it difficult to determine the full extent of contamination. The Washington State Department of Ecology was concerned about the site’s soil contamination and also the effects of the contamination on the properties groundwater. Therefore, the DOE requested that the site’s soils be retested at the same locations and analyzed using lower detection limits to determine the extent of PAH concentrations. The DOE also requested that the site’s monitoring wells be tested to ensure the contamination had not migrated to the groundwater. With the results of the soil and groundwater testing, American Property Development seeked to obtain a “No further action.” letter from DOE under the guidance of the MTCA Chapter 70.105D RCW.

Merit completed a thorough Phase I investigation then implemented the Phase II investigation consisting of the required soil and groundwater testing as requested by the DOE. We collected and submitted for PAHs analysis 29-shallow soil sample in the locations of previously collected samples and five groundwater samples. Merit Engineering conducted sampling activities using EPA guidance and regulatory compliance procedures. We ensured that cross-contamination did not occur by researching previous levels of contamination at each soil sample location and collecting samples in order from locations of least known contamination to highest known contamination. Groundwater samples were collected using dedicated, disposable sampling equipment at each monitoring well and rigorous decontamination methods were also used on non-disposable equipment transported between sample locations.

The soil and groundwater samples collected by Merit Engineering environmental specialists were analyzed by an environmental testing laboratory. The results concluded that soil contamination was below Method A cleanup standards and groundwater had not been affected by PAH contamination. The DOE granted a “No further action.” letter to APD.

Merit Engineering was also involved in the construction phase of the project. Merit was onsite to observe and provide recommendations for rockery wall installation, footing excavation, groundwork, and any backfill and/or structural fill placed at the site. We also provided laboratory work and material testing services throughout the construction phase.

Go Back