Problems/Comments

During an expansion project for the House of Harley facility in September 2001, a 500 gallon heating oil UST was discovered and removed from the northeast corner of the building footprint. During the UST removal petroleum contamination was observed. Soil screening and samples were collected from the excavation and stockpiled soils for laboratory analysis. Impacted soil from the site was excavated to various depths and as deep as approximately fifteen feet below ground surface (bgs) where the groundwater interface was encountered. Laboratory samples collected from the excavation limits beneath the former UST yielded concentrations of DRO, PAHs, and VOCs above ADEC cleanup levels. Soil that remained within the building footprint was found to be clean through screening, except for at the groundwater interface. Due to the road infrastructure, contaminated soil remained at the eastern sidewall of the excavation west of the Barbara Drive right-of-way. DRO was detected at 5.1 mg/kg to 5,400 mg/kg in samples collected by DOWL in the UST area. Removal of all contaminated soil was constrained vertically by the water table and horizontally by the building footprint and Barbara Drive right-of-way. The former UST was used at the former Polar Bear Motel. In October 2002, three soil borings and one direct push microwell were installed. Soil samples were collected, and field screened from three of the borings which were all completed as monitoring wells. Soil samples collected from MW-3 and MW-4 met MTG soil cleanup levels for DRO, Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) compounds. MW-1, located east of the former UST in the Barbara Drive right-of-way, exceeded the Table C groundwater cleanup level for DRO at 2,240 µg/L. Monitoring wells MW-2, MW-3 and MW-4 yielded detectable levels of DRO in groundwater samples with results well below ADEC cleanup levels. Groundwater flow direction was calculated southeast toward MW-1. In August 2020, the wells were recovered, groundwater sampled, and elevation measurements from MW-1 through MW-4 were taken. Groundwater elevations and contour mapping show the groundwater gradient in the parking lot area north of the House of Harley building in the vicinity of wells MW-2, MW-3, and MW-4 to be relatively flat, and the groundwater flow on the east side of the parking lot to be from MW-2 towards MW-1. It is possible that MW-1 groundwater elevations may be subject to the influence of underground utilities in Barbara Drive or some other factor. It was noted that in some cases, shallow groundwater can channel along permeable pipe bedding provided in buried utility trenches. The groundwater elevations in the parking lot were relatively level with a slight gradient towards Fish Creek. While the parking lot groundwater gradient is flat, groundwater elevations on the east side of the property showed a relatively steep gradient from MW-2 to the southeast towards MW-1. Four wells were sampled for DRO, GRO, PAHs, and VOCs. DRO was detected in all four monitoring wells. The sample from MW-2 was the only DRO exceedance above the ADEC Table C groundwater cleanup level of 1,500 µg/L. All other results were below Table C groundwater cleanup levels for all other contaminants. Monitoring well MW-2 yielded DRO at 1,820 µg/L compared to a cleanup standard of 1,500 µg/L. Additionally, 1,2-Dichloroethane was also detected at MW-2, however it was an estimated value detected well below the cleanup level and below the LOQ. MW-2 was well below the cleanup for all other contaminants. Results from MW-1 and duplicate sample MW-X were below Table C groundwater cleanup levels for all contaminants. DRO was detected at 1,180 µg/L in both the primary and duplicate sample, below the 1,500 µg/L Table C groundwater cleanup level. Additional detections at MW-1 above the limit of quantitation (LOQ), but substantially below cleanup levels were reported for the following contaminants: GRO, Isopropylbenzene (Cumene), n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, 1-Methylnaphthalene, Acenaphthene, and Fluorene. MW-1 was well below the cleanup for all other contaminants. Monitoring wells MW-3 and MW-4 yielded DRO results of 0.666 mg/L and 0.664 mg/L respectively, below the 1,500 µg/L Table C groundwater cleanup level. Both wells yielded GRO at estimated values well below the 2,200 µg/L Table C groundwater cleanup level. MW-3 and MW-4 were well below the cleanup for all other contaminants. In May 2021, groundwater sampling and elevation measurements of well MW-1, MW-2 MW-3, and MW-5 occurred. MW-1 was sampled for DRO and all other wells were sampled for DRO, GRO, PAHs, and VOCs. DRO was detected in all four monitoring wells. All well samples were well below Table C groundwater cleanup levels for all contaminants analyzed. In September 2021 groundwater sampling and elevation measurements of well MW-1, MW-2, and MW-6. MW-1 was sampled for DRO and all other wells were sampled for DRO, GRO, PAHs, and VOCs. DRO was detected in all three monitoring wells. All well samples were well below Table C groundwater cleanup levels for all contaminants analyzed.

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