Site Investigation: Overview

1.     Summary

The site investigation focuses on confirming whether any contamination exists at a site, locating any existing contamination, and characterizing the nature and extent of that contamination. It may include the analysis of samples of soil and soil gas, groundwater, surface water, and sediments. The examination of contaminant migration pathway is as integral part of site investigation as a baseline risk assessment may be needed to calculate risk to human health and the ecosystem.

2.     Site Investigation Methods

Typical activities included in a site investigation are:

• Identification and selection of appropriate technologies that allow site investigation and meet the required level of data quality (e.g., field measurement technologies, field sampling methods),
• Determination of the environmental conditions at the site:

-           Sampling and analysis to find out the nature, extent, source, and significance of the contamination present at the site,

-           Sampling and analysis to assess the physical, geophysical, and ecological conditions at the site,

-           Interpretation of the results t characterize site conditions,

• Baseline assessment of the risk the site may pose to receptors of concern. Pathways that should be considered are:

-           Soil and dust - direct contact, ingestion, or inhalation,

-           Water - ingestion and inhalation,

-           Air - inhalation and ingestion,

• Site-specific risk assessment to derive clean-up levels if that approach would result in more reasonable clean-up standards, or if clean-up standards are not available,
• Revision of assumptions about the site based on data gathered during the site investigation.

Technical methods needed to perform the site investigation activities are for example:

• Field sampling

-           Direct-push sampling,

-           Sampling based on drilling methods,

-           Passive diffusion bag samplers,

-           Soil gas sampling,

-           Single and continuous water sampling,

-           Integral pumping tests,

• field analytical methods

-           In-situ analysis (e.g., fiber optics, laser induced fluorescence, geophysical measurements, gamma radiation measurements),

-           Ex-situ (detector tubes, field bioassessments, photo- and flame-ionization detectors),

• laboratory analytical methods

-           Gas chromatography,

-           Spectroscopy,

-           Immunoassays,

-           Toxicity tests.

3.     Sources for Site Investigation Methods

Sources where information on site investigation methods can be obtained (appropriate media, applicability, performance, costs) are:

• Technical standards,
• Guidelines,
• Environmental protection agencies,
• Offices for testing and materials,
• Environmental databases.

4.     Literature

American Society for Testing and Materials (1998):

Standard Guide for Environmental Site Assessments: Phase II Environmental Site Assessment Process. West Conshohocken. E 1903-97.

American Society for Testing and Materials (1998):

Standard Guide for Accelerated Site Characterization for Confirmed or Suspected Petroleum Releases. West Conshohocken. E 1912-98.

U.S. Environmenal Protection Agency (2000):

Data Quality Objectives Process for Hazardous Waste Site Investigations EPA QA/G-4HW. Final.Office of Environmental Information. Washington D.C. EPA/R-00/007.

U.S. Environmental Protection Agency (2001):

Brownfields Technology Primer: Requesting and Evaluating Proposals That Encourage Innovative Technologies for Investigation and Cleanup. Office of Waste and Remedial Response. Washington D.C. EPA/542/R-01/005.

U.S. Environmental Agency (2001):

Resources for Strategic Site Investigation and Monitoring. Office of Solid Waste and Emergency Response. Washington D.C. EPA/542/F-01/030