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 40 of 136
For a detailed exposition assessment information about the amount of input, characteristic
of input like temporary trend, frequency and spatial distribution) as well as data
about the behaviour of a substance in the environment are necessary. Moreover assumptions
like sewage quantity and dilutive factor between sewage treatment plant
runoff and receiving water must be made. If no precise information about the kind and
the location of the entry as well as the prevailing environmental condition are known, an
exposition assessment based on scenarios are made. In this situation both a typical input
and dilution scenario and the worst case situation are proved. From these data the
predicted environmental concentration (PEC) can be assessed [FENT 1998].
The hazard or risk potential of a substance is its potential to harm humans and environment
based on disadvantageous characteristics. This potential is specified by the
physical-chemical and toxicological characteristics of the substance and the ecotoxicity.
At the effect evaluation it is checked if the substance is hazardous to humans and
nature. This evaluation is based on the acute toxicity not until higher toxical compounds
the chronical toxicity is integrated. The bioaccumulation is not yet regarded much but is
an important criterion. The aim of the evaluation of the ecotoxicological hazardousness
of a substance is the derivation of values for environmental concentrations at which a
damage of the ecosystem is less probable [FENT 1998]. The author continues that the
hazard evaluation is a result of the combination of exposition evaluation (amount and
exposition) and the effect evaluation. It contains an evaluation of the environmental
risks by using a substance based on input and substance characteristics determining
the exposition concentrations and possible effects.
If the hazard evaluation shows that a substance with endocrine characteristics reaches
the environment in relevant amounts a risk assessment must be done. Here the possible
dimension, the frequency and the consequences of a contamination based on a
detailed exposition assessment are estimated. The risk assessment considers the occurrence
probability [FENT 1998].