Tern Island Project
- Excavation, Transportation, and Disposal of Soils contaminated
with polychlorinated biphenyls (PCB)
Work Description:
Chase Environmental Group was contracted to provide contaminated
soil removal at an United States Fish and Wildlife Service
(USFWS) Nature Preserve located in the Hawaiian Islands
National Wildlife Refuge. The site had been the former location
of a LORAN navigation station operated by the US Coast Guard
until the mid 1960’s.
This project was complicated
due to several factors. The area excavated was located on
a coral atoll located approximately 450 miles northwest
of Honolulu, Hawaii. The site is managed by the USFWS and
is home to several threatened and endangered species. The
area to be remediated was located adjacent to the Pacific
Ocean, which limited equipment mobility and access, consequently
Chase constructed a retaining wall to separate the remediation
area from the ocean.
Chase established a grid
system in the remediation area utilizing coordinates established
during previous site investigations. Each grid was excavated
using tracked excavating equipment. Chase placed the material
into DOT approved soil bags and transported it out of the
affected area using an all-terrain forklift. The bags were
weighed and placed into cargo containers, which Chase then
loaded onto a small lightering barge. The lightering barge
transported the containers to a larger barge anchored approximately
one mile offshore. The containers were transferred to the
larger barge using a crane. The cargo containers were shipped
to Oregon for disposal.
The material excavated contained
a substantial amount of debris which consisted of concrete,
metal grates, glass, machine parts, metal pipes, truck axles,
steel beams, and rebar. This material was segregated by
hand or using the excavator and placed into separate cargo
containers.
Tern Island Project
Photos
Another complicating factor
was the proximity of the remediation site to the ocean.
The excavation was scheduled so that soil/debris were excavated
near the retaining wall during periods of low tide. The
material excavated near the retaining wall was stockpiled
and allowed to drain prior to loading into the soil bags.
After each grid was excavated,
a Chase technician obtained confirmatory samples and completed
field immunoassay testing using the SDI Rapid Assay PCB
test kit. Over 800 tests were completed.
A total of 1690 CY of non-hazardous
PCB soils were disposed. There were a total of six-55 gallon
drums of capacitors, transformers and batteries, which were
disposed of as hazardous waste and eight drums of soil which
was disposed of as TSCA waste. There were eight cargo containers
of debris disposed.
Location:
Tern Island, Hawaiian Islands National Wildlife Refuge,
450 miles NW of Honolulu, Hawaii
Regulatory Basis:
RCRA, TSCA, Special Waste / OSHA
