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Polynuclear Aromatic Hydrocarbon (PAH) contamination was identified within two (2) areas at the Sunrise Shopping Center facility: within the area of a former heating oil UST behind the 2414B 10th Avenue tenant space (location of monitoring well MW-4) and within the southern extent of the site (location of MW-3). The PAH contamination continues to be monitored during quarterly groundwater monitoring.
Two (2) quarterly groundwater sampling events were conducted during the first semi-annual 2020 reporting period. The first quarter sampling was performed on January 17, 2020, with results provided in the Quarterly Groundwater Sampling Report dated March 4, 2020, and the second quarter groundwater sampling was performed on May 5, 2020, and the results were provided in the Quarterly Groundwater Sampling Report dated June 15, 2020. The quarterly sampling indicates that PAH groundwater concentrations continue to fluctuate in MW-4, with the most recent concentrations increasing to levels above the Enforcement Standards. While this increase in concentration is of concern, the spike in concentration appears to be associated with the higher than usual groundwater table elevation which allows contamination within the smear zone to leach into the groundwater. A spike in contamination coinciding with an elevated groundwater table has been noted previously.
The PAH concentrations in MW-3 also fluctuate between sampling events, but largely remain at levels above the Enforcement Standard. The groundwater concentrations are influenced by the change in groundwater table elevation change and the large amount of contaminated fill material within the area of MW-3 and along the southern property boundary.
No active remediation is currently being conducted nor is any proposed. While PAH concentrations in MW-3 and MW-4 continue to fluctuate with no discernable trend, the contamination appears to be isolated to the immediate area of the two (2) wells. There is no exposure to this residual contamination because drinking water is provided by the municipality via Lake Michigan and the groundwater ingestion route of exposure is incomplete. There are no potable groundwater wells on-site. Quarterly sampling will be continued with the third quarterly sampling event to be completed in July 2020, and the sampling results submitted in a quarterly report.
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