Geoenvironment Impact Mitigation and Management - Sustainable Practices in Geoenvironmental Engineering - page 360

• Consequence of industrial operations : Resource extraction (minerals, hydrocarbons,
aggregates, etc.) and farming (cattle and other livestock) provide the major sources
for chemical stressors. The discussions on the types of stressors and their sources
have been reported in the previous chapters. Mitigation of stressor impacts begin
with source control and implementation of “collect and treat” systems. For chemi-
cal stressors (contaminants) that ind their way into the subsoil, the techniques for
mitigation will be discussed in this and the next chapter.
• Leachates, spills, accidents during hazardous material transport, illegal dumping, etc. :
Leachates leaking from containment systems, spills, accidents of trains during
transport resulting in ires or leakage of hazardous materials and illegal dumping
of chemical-type liquid and solid wastes are some of the major sources of chemi-
cal stressors found in the subsurface soil. These are, by and large, point source
chemical stressors.
The discussion on procedures for mitigating the impacts from the stressors will be found
in the rest of this chapter and continued in the next chapter as options in remediation.
10.4 Chemical Stressors: Contaminants
Regardless of the cause of the geo-disaster, the primary concern arising therefrom is
in respect to the health of the geoenvironment and the biotic receptors in the presence
of contaminants in the subsoil. Contaminants are chemical stressors that can severely
affect the quality of water and groundwater resources, and soil quality. These (contami-
nants) include non-point source contaminants such as herbicides, pesticides, fungicides,
etc., spread over large land surface areas, and point source contaminants from efluents,
waste treatment plants, and liquid discharges as wastes and spills from industrial plants
(e.g., heavy metals, organic chemicals). The previous chapters dealing with urbanization
and industries have shown that liquid and solid waste discharges, together with rejects,
debris, and inadvertent spills in the plants, all combine to create signiicant threats to the
health of biotic receptors and also the environment. To demonstrate the magnitude of
the problem, we can cite the example of sites contaminated with hazardous wastes and
other material discards. In the U.S. Environmental Protection Agency (USEPA) (2004)
report on the status of the future of site remediation, it is estimated that up to 350,000
contaminated sites would need to be cleaned up over the next 30 year at a cost of $250
billion.
The impact from the presence of contaminants in the ground needs to be mitigated
and managed, as a beginning step toward protection of the resources and the natural
capital in the geoenvironment. This is a necessary step toward achievement of a sus-
tainable geoenvironment. The emphasis should be placed on using the properties and
characteristics of the natural soil-water system as the primary agent for such purposes.
The motivation for this is not because of the high expenditures incurred with the use of
various technological remediation schemes and processes, but because it allows one to
address contaminant sources that encompass the range from point-source to non-point
source. Managing the impact from non-point source contamination with technological