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in urban treatment plant effluent (upgrading of treatment procedures in existing plants, relatively
rapidly; building of treatment plants if not already existing, medium time terms), reduction of the
use of fertilizers on crop land, application of animal manure on land, restriction of the number
of animals (e.g., cattle, etc.) per unit of available surfaces of pastures, adoption of strip farming,
etc. (requiring often long-term education and administrative regulation about farm practice).
Further, it should not be ignored that cost evaluations are not always straight forward.
E.g., installation and running costs for urban sewage treatment plants are relatively easy to
estimate within the usual uncertainty range of changing costs, although actual cost over-runs
are frequent. On the other hand, the cost evaluation of sludge deposition is much more uncertain
because sludge deposition may create new and unexpected problems, such as limited site
availability for deposition, undesirable environmental impact such as toxicity if used in
agriculture, a.o. Reformulation cost of detergents will be hidden in consumer costs, as are
installation and running costs of say food processing industries that are required to clean their
effluent, etc. On the other hand, there may also be gains, say to farmers using less fertilizers,
which however may be offset by required changing work procedures.
With the same token, benefits cannot always or exclusively be evaluated in terms of
tangible money gains. Benefits such as increased amenities e.g., cleaner bathing beaches,
reduced health risk, augmented sport fisheries, etc. are still desirable societal objectives for
themselves regardless of the extent of connected economic gains. Economic returns are often
indirect, and as such difficult to evaluate.
For further worthwhile reading on the subject, in which details are elaborated on several
aspects touched upon, refer to Fole and Kåberger (1991).
B. REMEDIAL ACTIONS AND CONTROL MEASURES
9. MONITORING, PREDICTION AND DECISION MAKING
Monitoring, in the context of the assessment and protection of the marine environment,
is here defined as the repeated measurement of an activity or a contaminant or of its direct or
indirect impact (Villa, 1989; Rinaldi, 1990; Vollenweider, 1992; Bonalberti et al., 1992; Bucci et
al., 1992; Volterra et al., 1992).
In practical terms, monitoring can fall within the following three categories :
- monitoring for regulation purposes (control);
- monitoring of levels and trends;
- monitoring for scientific purposes.
The monitoring for scientific purposes is generally the main step for establishing
monitoring of levels and trends which in turn provides useful information for defining the
parameters of control (monitoring for regulation purposes).
In order to define the monitoring programmes of the marine environment, the following
operational objectives, which have a high degree of universality, must be taken into
consideration: