Sisters Island Remedial Action and Demolition

Brice performed demolition, debris removal, and a removal action at a Former Dump Area on Sisters Island, Alaska. We first removed approximately 160 cubic yards (cy) of inert debris to 7 feet bgs and included liner, plastic, tires, household trash, metal debris, cable, glass, a large boat anchor, a welder, a compressor, a 500-gallon empty non-intact aboveground storage tank, insulation, pipe, corroded 4-foot empty steel cylinders, empty fire extinguishers, hardened gallon paint cans, and parts of towers. In addition, we removed several other types of debris with the potential to release contaminants including 1,565 lbs of batteries; 237 lbs of dried paint cans; 635 lbs of capacitors from E-waste panels; and 7 cy of soil identified as hazardous waste with PCB concentrations greater than 50 mg/kg. Debris was properly recycled or disposed of in various approved facilities. Brice also collected waste characterization samples from the excavated soil. Analytical results showed one stockpile of soil associated with E-waste and capacitors was contaminated with PCBs; we transported and disposed of the soil as TSCA-regulated hazardous waste.

Following debris removal, we collected analytical soil samples which were compared to Alaska Department of Environmental Conservation 18 Alaska Administrative Code 75, Method Two, Over 40-Inch Zone cleanup levels for human health and ingestion criteria. Based on results, Brice recommended that isolated areas showing elevated levels of hexavalent chromium, PCBs, and dioxins be removed, which would allow for Cleanup Complete determination. Brice will perform the removal action in 2019.

Brice also removed and recycled the Directional Finder tower and four target antennas and excavated one cy of soil. Following excavation, we collected four soil samples from the excavation limits for lead analysis. Lead concentrations in all four confirmation samples were less than the ADEC cleanup level or were not detected.