Environmental risks and impacts - Environmental Deterioration and Contamination: Problems and their Management - page 218

Figure 8.10 Equal balance of ecosystem health, human health and industry/economy.
9.3 Risk assessment
Risk assessment is one of the most useful interpretation tools of the gathered historical
and measured data about the status of the environment or an environmental problem
such as the production and use of a chemical or a contaminated site. Pollution of
the environment is a process, starting with the release from a source, followed by
the transport of the contaminant in the environment and finally, its meeting with the
receptor and the realization of the adverse effect of the contaminant. This complex
process can be stopped in the source or on the transport pathway, but if this has not
been done, the receptor should be prevented by restrictions or preventive measures or
equipment, etc. When we cannot stop a further spread of the contaminant near the
source, the situation becomes worse. The best strategy is not waiting but preventing
the dangerous contaminant from being released, or reducing the probability of its
release. The probability of the coming true of the adverse effects originating from the
hazardousness of a chemical substance should be reduced as much as possible. The
measure of the probability and the extent of the damage if it has occurred depend
on the extent (quantity) of environmental risk of chemical substances. It also can be
expressed as the ratio of two concentrations: the environmental concentration in a
certain time point and locality and the (maximum of) no-effect concentration which
does not adversely affect the receptor (humans or any living organisms) in question.
The ratio of the predicted environmental concentration (PEC) to the predicted no-effect
concentration (PNEC) gives a so-called Risk Characterization Ratio (RCR), which