Conducting Subsurface Environmental Investigations in Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 117

4
ConductingSubsurfaceEnvironmental
Investigat ionsinUrbanWatersheds
4.1 Introduction
This chapter presents the sequence of science-based procedures used to evaluate a specific
land parcel or larger area for environmental contamination and assess its environmental
risk. We conclude with specific methods available to environmental professionals for col-
lecting samples from the soil, groundwater, sediments, surface water, and air. First, we
define and present some basic concepts necessary for understanding and framing the con-
cept of a subsurface environmental investigation.
The environment is a broad term encompassing all living and nonliving things on the
Earth or some region thereof (United Nations 1987). This definition identifies the natu-
ral world existing within the atmosphere, hydrosphere, lithosphere, and biosphere, and
also includes the built or developed world (anthrosphere). Environmental risk is defined
as the probability of an event resulting in an adverse impact upon the environment or
humans (Fletcher and Paleologos 2000). Environmental risk increases when a completed
human pathway occurs or a sensitive ecological system is impacted (USEPA 2002).
Environmental assessment contributes to our understanding of human impacts on the
environment and is considered the first step in evaluating and ensuring the long-term
viability of Earth as a habitable planet. For hundreds of years, the practice of conducting
assessments to determine adverse environmental impacts was never a significant priority.
Since the last quarter of the twentieth century, however, significant amounts of human and
financial resources have been mobilized to evaluate the actual or potential environmental
damage incurred from human activities of the past, present, or those proposed for the
future.
Environmental investigations are conducted when there is the likelihood that certain
environmental contaminants exist at a specific property or site having the potential to
cause material harm to human health or the environment historically, presently, or in
the foreseeable future. Some subjectivity is inherent in the decision to proceed with an
environmental investigation at any given property. This uncertainty occurs because most
properties contain, store, or at some time have used substances that could pose potential
harm to human health and/or the environment. For instance, most households store and
use potentially harmful substances, including
• Cleaners (ammonia)
• Solvents (acetone, mineral spirits)
• Gasoline for lawn maintenance, snow removal, and other purposes
• Pesticides (e.g., Permethrin, used for flea and tick control)
• Herbicides (e.g., glyphosate)