Conducting Subsurface Environmental Investigations in Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 161

FIGURE 4.30
Airflow pattern through outdoor particulate sample.
(From United States Environmental Protection Agency,
List of Designated Reference and Equivalent Methods for
Air Sampling , United States Environmental Protection
Agency National Exposure Research Laboratory,

Washington, DC, 2008.)

• Starting time and date
• Ending time and date
• Airflow rate
• Temperature ranges during sampling
• Relative humidity difference during sampling
• Summary of conditions that may affect results (construction activities in the
area, etc.)
• Barometric pressure at start and end

4.4 Summary and Conclusion
Environmental subsurface investigations are very detailed scientific investigations. These
investigations collect enormous amounts of geologic and hydrogeologic information, and
significant amounts of other information. All of this information allows the profession-
als conducting the investigation to determine the existence of contamination at a site or
property, and if the level of any contamination present requires a remedial action because
it presents an unacceptable risk to human health or the environment.
Environmental investigations must be conducted with a high level of scientific care for
several reasons: (1) because contaminants requiring a remedial action may be present at
very low levels and precautions must be taken to minimize the chances of any cross-con-
tamination; (2) because the investigation and potential remediation must be conducted in
such a manner as to enable their admission in a court of law; and (3) to protect the inves-
tigators from any exposure to contaminants while collecting and handling samples taken
during field activities.