Because of the historic use of leaded gasoline, elevated concentrations of aerially deposited lead (ADL) are present along older highways. Typically, these soils would need to be removed and disposed of in a landfill; however, Caltrans has a variance that allows for burial within the Caltrans right-of-way under certain conditions.
Under contract with Caltrans, Geocon has performed about 1,600 aerially lead deposit studies throughout the State. When a buried fiber optic cable was proposed along State Route 50 in Sacramento and West Sacramento along with associated service pull boxes, Geocon was tasked with drilling approximately 200 shallow borings along the fiber optic alignment, testing for ADL and performing statistical analyses. Based on the results, Geocon provided recommendations for reuse of soil generated by horizontal bores for the fiber optic project with a minimal quantity requiring disposal at a Class I Disposal Facility.