Summit performed an aerial deposited lead investigation along Route 91 in Orange and Riverside Counties, California. The objective of the investigation is to re-evaluate soil that has previously been determined to contain hazardous levels of 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 was 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 using statistical data analysis. Soil samples collected from the site were subsequently analyzed for total lead, soluble lead, and pH.

Summit’s conclusions were developed based on evaluating several different scenarios. The criteria for these scenarios include first evaluating the entire data set and subsequently evaluating the same data minus selected “Hot Spots”. These hot spots represented areas where laboratory data showed concentrations of lead which appeared to be significantly elevated above the vast majority of the overall data. Based on the results of these efforts the majority of the material was able to be reclassified and reused as part of the right of way construction project providing significant cost savings to the State and client.