Stressors and Soil Contamination - Sustainable Practices in Geoenvironmental Engineering - page 32

As indicated in Chapter 1 that geoenvironmental impacts arising from natural causes
such as earthquakes, tsunamis, tornadoes, loods, typhoons, and hurricanes do not fall
within the purview of this topic. The distress and damage to the geoenvironment can be
readily perceived because the energy generated in these events in the form of forces and
stresses can cause substantial physical damage to the geoenvironment and considerable
loss of life. Although many of the sources or causes of the impacts are generally obvious,
there are many that are not. This is because we do not have any hard and fast rule as to
what constitutes an impact, and more importantly, when the particular impact under con-
sideration causes irreversible damage. Damage to the geoenvironment of the same scale
and magnitude as earthquakes and hurricanes can be obtained as a result of man-made
activities, such as landslides and contamination of ground and receiving waters. However,
more often than not, the impacts to the geoenvironment resulting from anthropogenic
activities associated with the production of goods and services are less dramatic. That
being said, they nevertheless endanger public safety and present health-threatening prob-
lems and issues.
2.2.1 Stressor Impacts on Soils
The categories of stressors include such groups as (a) hydraulic, (b) mechanical, (c) thermal,
(d) chemical, (e) geochemical, and (f) biologically mediated. Some of the main impacts
resulting from the actions of these types of stressor groups that have been discussed by
Yong et al. (2012) are listed below.
2.2.1.1 Hydraulic
The stressors that classify under the hydraulic group are directly related to water and
its actions in soils—with types of actions that result in application of pressures that act
directly on and within a soil mass. The impacts from these stresses could:
• Initiate piping that could undermine the stability of overlying structures and facil-
ities (adverse impact).
• Trigger erosion, landslides, debris low, and quick soil conditions from excessive
porewater pressures, self-detachment of soil particles (adverse impact).
• Restructure affected soils because of the pressures resulting in changes in soil
properties and behaviour (could be adverse or beneicial impact).
• Dilute or decrease contaminant concentration in contaminated soils (generally
considered to be beneicial).
• Initiate or increase advective transport of contaminants in the soil (adverse or ben-
eicial impact, depending on initial conditions).
• Detach sorbed contaminants and contribute to the environmental mobility of the
contaminants (probably more adverse than beneicial—again depending on initial
conditions).
• Affect biological processes through changes in natural habitat and energy sources
(mostly adverse impact).
• Inluence natural soil-weathering processes leading to alteration and/or transfor-
mation of susceptible minerals (could be adverse or beneicial).