D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 7 of 136
on the pollution level even if no dilution by pure inflows happens. Bacteria and ciliates
withdraw permanent organic protective substances by their metabolic activity from the
water in which they thrive [JAEGER 1994]. Thus, micro-organisms have the potential to
eliminate protective substances and to purify the waters in a certain period.This selfpurification
capacity of waters is used in sewage treatment plants. Nowadays waste
water is often contaminated with substances which cannot be eliminated or can only be
eliminated in an inadequate quantum by these plants. Thus, the receiving water is
loaded exceedingly. With respect to "new contaminants" and the economic efficiency of
treatment, the minimisation and further processing of treatment by-products, improvements
in water treatment technologies are needed. A special problem are pharmaceutical
products and pathogenic germs, passing partly intact through the treatment plants.
Here exists a great risk of generating resistances so that new purification levels and an
upgrade of the treatment plants are needed. With regard to these new purification levels
specific options for deep lakes are analysed in this report to reduce future input of
pollution to a minimum. The above mentioned anthropogenic load of aquatic ecosystems
is not only a result of sewage treatment plant effluents and the introduction of only
moderate pre-treated waste waters. The rainwash from agricultural areas and the animal
husbandry contaminate the water of lakes, rivers and partly the groundwater significantly.
A protection of great deep lakes being drinking water reservoirs is important because
they have to comply with a certain standard to guarantee the postulated drinking water
quality. Moreover, pollutants affecting the drinking water quality are also able to have a
negative impact to the aquatic ecosystem. For this reason, these reservoirs have to be
monitored to detect impairments in time. Information on pollutants, pollutant sources,
pathways and impacts with respect to great deep lakes were compiled in this report.
The qualitative and quantitative vulnerability of the investigated deep lakes with relevant
organic contaminants and heavy metals were also to be named. The main objective of
this task, however, was a survey of relevant contaminants, their threshold values and/or
limit values with respect to the European Drinking Water Directive. But also the current
valid threshold values of relevant substances and compounds in regard to other European
and national directives like the Drinking Water Directive and the Bathing Water Directive
are considered. In doing so, the relevance of the list of priority substances determined
on European level concerning the investigated areas was considerdd. The
behaviour of the detected substances in the aquatic environment is described and the
possibility of (new) detection methods as standard test is shown.