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EFFECTS ASSESSMENT
equilibrium partitioning method can be used to derive a PNECsoil. Otherwise, assessment factors
are applied (see Section 3.6).
Biotic and abiotic effects, such as acidification, are addressed for the atmosphere. In view of the
lack of suitable data and the fact that no adequate methods are available yet to assess both types
of effects, a provisional strategy is described in Section 3.7.
Standard assays of ecotoxicological effects usually provide information about the direct toxic
effects of a substance. Chemicals showing bioaccumulation and biomagnification may pose an
additional threat due to exposure of organisms higher in the food chain, e.g. top predators. This
phenomenon is called 'secondary poisoning' and has to be addressed if a chemical fulfils several
criteria, e.g. indication of a bioaccumulation potential. If this is the case, the oral intake of a
chemical via fish or worms (PECoralfish and PECoralworm) is compared to a PNEC for fish- or
worm-eating mammals or birds. This approach is described in Section 3.8.
Knowledge on endocrine disrupting effects of some substances is presently under development.
When substantial evidence on such effects is available, this should be taken into account on a
case-by-case basis in the derivation of the PNEC for each compartment of relevance. Existing
knowledge does not allow a more standardised approach for risk assessment of such substances.
It is recognised that experience with several of the described effects assessment methods is
lacking. Thus, assessments by use of these types of methods can be uncertain. However, the
methods presented make it possible to identify if the compartment under consideration is
possibly “of concern” and whether further data, e.g. testing on relevant organisms for that
compartment, should be obtained.
The environmental part of the risk assessment should contain some general reflection on the
mode of action of the chemical. Cross-reference to relevant sections in the human health part
may be important. For example when a chemical is found to have effects on gonad development
in fish and similar effects have been observed in laboratory mammals. Identification of
similarities in the nature, intensity and time scale of effects between species, as well as in the
susceptibilities of different receptors, will allow a better understanding of the actual risk to these
organisms to be obtained and help in the identification of issues of concern (IPCS, 2000).
3.2 EVALUATION OF DATA
3.2.1 Ecotoxicity data
During both steps of the effects assessment it is very important to evaluate data with regard to
their adequacy and completeness. This is particularly important for existing substances that have
been extensively studied where there may be a number of test results available beyond the baseset.
This section puts forward general guidelines on the evaluation of ecotoxicity data. The term
adequacy is used here to cover the reliability of the available data and the relevance of that data
for environmental hazard and risk assessment.
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