Summit performed an aerial deposited lead investigation along Interstate 5, in Santa Clarita, California as part of a highway construction project for the State. 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 on-site.

The data collected from the limited soil investigation and laboratory testing was used to profile soil for both export and on-site reuse. Soil samples collected from 18,000 cubic yards of stockpiled soil located at the site were analyzed for total lead, soluble lead, and pH. As a result of Summit’s analysis, all of the stockpiled material previously classified as Z-2 material was 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. 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.