Summit performed an aerial deposited lead investigation along Interstate 10, in Baldwin Park, California. The objective of the investigation was to re-evaluate soil that had previously been determined to contain aerially deposited lead due to the historical use of leaded fuels by freeway traffic. The purpose of this reclassification was to increase the amount of soil that could be classified for reuse onsite. The data collected from the limited soil investigation and laboratory testing was used to profile soil for both export and on site reuse. Soil and water samples collected from the site were subsequently analyzed for total lead, soluble lead, and pH, and further analyzed using statistical data analysis methods. As a result of Summit’s analysis, 80,000 tons of material previously classified as Z-2 and Z-3 material were reclassified as Y-1 or unrestricted reuse.

Summit’s conclusions for soil reuse on site were based on guidelines set forth by the DTSC, Lead Variance issued to Caltrans on June 30, 2009 (DTSC Variance). Laboratory analytical results for lead were compared to the guidelines of the DTSC Variance for potential reuse of the soils as fill within the Caltrans right-of-way.