Stressors and Soil Contamination - Sustainable Practices in Geoenvironmental Engineering - page 38

• Establish a general or broad impact-identiication scheme. By doing so, this allows
us to look for the source of the impact. Knowledge of the stressors and their source
provides one with a better appreciation of the extent and details of the impact. In
looking for the stressors responsible for the impacts, it is necessary to separate
the stressor source from the impact , since it is not always easy to determine what
constitutes the impact.
2.3.1 Reference Frame
The geoenvironmental impact reference frame provides or speciies the targets in the total
land environment and the receiving waters contained therein. It provides a framework that
requires questions to be raised as to whether the actions arising from projects or events will
have adverse effects on the various physical and biological elements constituting the geoen-
vironmental compartment. The speciic case of a contaminated ground shown in Figure 2.2
(from Yong and Mulligan, 2004) is a good example of the application of the reference frame
for determination of geoenvironmental impacts. In this instance, one is concerned with the
impacts resulting from the presence of contaminants in the ground. We deine a pollutant
to mean a contaminant that has been identiied as a threat to human health and/or the
environment. These are generally toxic elements, chemicals, and compounds and are most
often found in priority pollutant lists of regulatory agencies. Contaminants , meanwhile, are
deined as substances that are not natural to the site or material under consideration. These
substances can include hazardous materials or elements, toxic substances, contaminants,
Atmosphere
Aquatic and
terrestrial biota
Contaminated ground with
contaminant plume
Aquifer
FIGURE 2.2
Schematic diagram showing contaminated ground with a contaminant plume as the source of health and envi-
ronmental threats. (From Yong, R.N. and Mulligan, C.N., Natural Attenuation of Contaminants in Soils , CRC Press,
Boca Raton, 310 pp., 2004.)