1.0 Introduction

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.