Scientific and engineering improvement of environmental risk management - Environmental Deterioration and Contamination: Problems and their Management - page 411

NICOLE is a leading forum on contaminated land management in Europe promot-
ing cooperation between industry, academia and service providers on the development
and application of sustainable technologies. It identifies research needs and promotes
collaborative research on contaminated sites and collaborates with other international
networks. NICOLE's website consists of a library with information on hundreds of
contaminated site cases, site investigation, risk assessment, risk management and
commercial aspects, projects and workshop documents (NICOLE, 2013).
10 UNCERTAINTY ANDVARIABILITY IN ERM
Risk and uncertainty are two basic ideas in environmental management and decision
making. Risk is defined as “probability of the possible outcome, meaning imperfect
knowledge on the scale, timing, type and frequency of the occurrence of the outcome.''
Uncertainty exists when the probabilities are not known or when their knowledge
is imperfect. Uncertainty can be caused by limitations in knowledge or limited avail-
ability of information, as well as biases or imperfections in the instruments, models or
techniques used. Using better suiting methods and models, the extent of uncertainty
decreases. Thus, uncertainty can be reduced by developing an improved knowledge
base, using efficient standardized methods. Uncertainty can be reduced by a stepwise
iterative assumption applying more and more refined methods and information. Risk
refers partly to uncertain consequences. Accepting risk means to expose oneself to a
significant chance of damage (deterioration, injury, health effect, loss).
Variability refers to variation that exists in the real environment. It is an inherent
property of a system that cannot actually be reduced by further information.
Risk management can be defined as choosing among alternatives to reduce the
risk, thus it implies the task of dealing with and recording the sources of uncertainties,
characterizing, quantifying and evaluating uncertainties.
By investigating the steps of environmental management (Figure 11.12), one can
identify numerous points, where uncertainties may largely influence the result of the
measurements or calculations. Risk management is typically based on data, equations
and models, which imply uncertainties. The environment, the objective of environ-
mental risk assessment and risk reduction itself and its users—both humans and
ecosystems—are highly “uncertain'' due to heterogeneities and continuous evolution-
ary changes as well as due to exposures to variable meteorological, climatic and other
natural impacts.
Figure 11.12 shows the two most frequently applied iterative cycles. Iteration
between risk assessment and monitoring: risk assessment identifies the parameters,
contaminants or receptors to monitor and monitoring provides data for risk assess-
ment. Iteration between risk reduction and monitoring: monitoring and risk assessment
calls the note for the unacceptable size of risk, and when the risk has been reduced
by a measure, it can be proved by environmental monitoring. Risk should be reduced
until an acceptable level has been reached.
Let us take an example. In the course of the application of the REACH regula-
tion (REACH, 2006), it has become clear that the generic risk assessment of chemical
substances for legislative purposes is associated with uncertainties, even if the envi-
ronment is an abstract quasi steady-state European environment. The derivation and