Scientific and engineering improvement of environmental risk management - Environmental Deterioration and Contamination: Problems and their Management - page 421

for testing toxicity and other adverse effects, the changing and uncontrolled test
medium during toxicity testing, test organisms that are well-known to be geneti-
cally and metabolically unstable, the improper selection of test duration (acute or
chronic) and the mixture of organisms used for testing;

- Monitoring is a time series of repeated assessments at the same “point''; the

obtained data are combined with seasonal, short-time and spatial uncertainties.
As one cannot step into the same river twice (Heraclitus), monitoring situations
are even worse because sampling removes the very part of the environment to be
analyzed in a laboratory, thus the same point cannot be sampled twice; the next
sample is a different one. If the frequency of sampling points and the scale of the
heterogeneities are the same, one has no chance to obtain valid data;

- Integrated monitoring uses physico-chemical, biological and toxicological mea-

surement tools in an integrated way to reduce uncertainties of the individual tools.
The results of the toxicological screening can be validated or refined by chemical
analysis, and by identifying which chemicals cause which adverse effects. Chemical
analytical results can be refined by toxicity data, which may prove the risk of an
existing chemical but may also prove the opposite, i.e., the chemical is harmless due
to its presence in biologically non-available or ineffective form. The synergisms of
the different methodologies make the characterization of biological availability
of the contaminants possible and indicate the presence of contaminants that have
not been or cannot be chemically measured;

- Time duration of monitoring and uncertainties show interesting relationships:

short-term data may be different from long-term trends due to variability of inter-
nal and external parameters. But an assessment of long-term trends results in uncer-
tainty reduction and provision of better quality information for environmental
management and decision making;

- Uncertainties are to be taken into account not only in contaminated site and risk

assessment but also in other risk management measures such as definition of the
target risk of a contaminated site and planning of remediation. These aspects are
discussed in detail in Volume 4.

11 WHAT IS NECESSARYTO FURTHER DEVELOP RISK
MANAGEMENT AND INCREASE ITS EFFICIENCY?

The use of chemical substances, including hazardous ones is an essential part of civilized
life. However, having experienced their adverse effects and risks, more efficient risk
management is required to control their risk. Production, transport, use and disposal
of chemicals have produced a large number of contaminated sites—a heavy legacy on
today's industry and society.
Contaminated site remediation, regeneration and rehabilitation are expected to
impose a severe burden on industry and agriculture as well as the public purse if
the we cannot change today's practice and make prevention and contaminated site
management more efficient.
A number of programs and projects have aimed to identify future approaches and
methodologies to enhance environmental management using the most advanced and