Phase II environmental site assessments are primarily employed after evaluation
of the Phase I audit results to acquire and measure contaminant levels
at the site and to help define the cost and extent of possible future
clean-up. Assessment may also be used as baseline studies to confirm contaminant
background levels prior to construction or purchase of a facility.
2.0 Scope of Work
The scope of work for any individual site assessment must be custom tailored
to the type of installation and most probable types of chemicals and materials
which may be of concern.
The following types of investigations may be warranted:
2.1 Soil Vapor Study
Soil vapor studies provide a rapid and cost effective method of mapping
the horizontal distribution of volatile petroleum and chemical vapors
in subsurface soils and waters. Soil vapor studies can be used to explore
petroleum refining, storage and distribution facilities and other installations
which have used or stored fuels, solvents or other petroleum based chemicals.
Soil vapor studies include collecting a grid of samples over the area
of interest and analysis for methane through butane light hydrocarbons,
C5+ gasoline range hydrocarbons, chlorinated solvents and other compounds
of concern. Results can be used to select boring and monitor well locations
which may be necessary to map the vertical distribution of contaminants
in soils and ground waters.
2.2 Soil Sampling
Conventional drilling and soil sampling programs can be employed to obtain
representative soil samples for laboratory analysis of petroleum constituents,
trace metals and other compounds of concern. Soil sampling programs should
be planned after a soil vapor study or other screening tool is employed
so that borings are placed to fully define the horizontal extent of contaminants.
2.3 Monitor Well Installation and Ground Water Sampling
The horizontal extent of ground water contamination can be mapped with
an appropriate number of ground water monitoring wells. Wells are typically
sampled for benzene, toluene, ethylbenzene, xylene (BTEX), total petroleum
hydrocarbons (TPH), trace metals and other water quality parameters.
3.0 Interpretive Report
The final interpretive report provides a comprehensive assessment of the
type, composition, vertical and horizontal distribution of potential contaminants
of soil, ground waters and effluents of the site. Results can be used
for planning more extensive site investigations to further define pollutants
or as confirmation of levels prior to site purchase or development.