Management of abandoned and contaminated land - Environmental Deterioration and Contamination: Problems and their Management - page 186

Proper decisions are based on the results of risk assessment, but not just based on
the risk value; the socioeconomic aspects are equally important in this phase of the
management of contaminated sites.
The owner may decide against taking any risk reduction measures, even in the
case of RCR

= 5 (five times the acceptable RCR = 1 limit) if he has two other sites

with an RCR 5. He may decide to act

immediately or postpone action, while monitoring and evaluating the site can show
the long-term trends of natural changes. The decision is largely influenced by the extent
of the problem (which is not reflected by the RCR ) such as the amount of chemicals
produced, used and discharged, the size of the contaminated area, population density
(number of endangered persons), and the amount of contaminated soil and water.
The decision on prevention, restriction or remediation can be a combination
of restriction (as an immediate intervention), prevention of future contamination
and remediation or partial or delayed remediation of the already contaminated
area, depending on other management tasks such as connected spatial planning or
construction works and their placement and timing.
If the decision on risk reduction is remediation, the next step is the selection of
the best possible and available technology. The best possible in this case means the
best fitting to the site, the problem, the budget and the requirement of the future land
use. The selected and applied remedial technology should be technologically efficient,
environmentally efficient (reducing existing risk and not generating new risks at local,
regional or global levels) and economically efficient. Finding the optimum from the
above point of view is a complex task because it needs a conscious concept and suitable
tools for measuring technological, environmental and economic efficiencies (see also
Chapter 12).
In general, prevention is one of the most efficient risk management tools. In the
case of contaminated sites, prevention is limited to hindering further contamination,
applying preventive technologies, such as physical, chemical or/and hydraulic barriers
or the prevention of recontamination of the site under clean-up.
To protect the workers, residents and the ecosystem around contaminated sites and
during remedial work, similar measures are used as in the case of technologies using
hazardous chemicals. These measures include restriction in land use, e.g., prohibiting
entry, or fishing, monitoring (air, water, dust, groundwater, damage to the ecosystem,
etc.), isolation, ventilation, protective clothing and equipment.
Restriction may influence the risk by the contaminated site at several points of the
conceptual model starting from the source (stop or reduce production or use, change
the chemicals), through the transport routes to the land uses or the receptors as shown
in Figure 7.5.
Figure 7.5 summarizes the possible points on the integrated risk model where
remediation and restriction can be applied to reduce the risk posed by contaminated
soil. Restriction by blocking the transport pathways may prevent the contaminants
from being further dispersed. Another possibility to reduce risk is restricting land
uses, i.e., prohibiting the entry to the area, forbidding drinking the water or using
the soil for agricultural production, and changing agricultural cultivars (e.g., only
energy plants). Restriction results in temporary reduction in the risk, however when the
restriction is lifted, the risk will raise to the previous level. Remediation provides a final
solution for the contaminated land by cleaning or otherwise decontaminating the soil

= 10, or a larger site with the same RCR =