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3 EFFECTS ASSESSMENT
3.1 INTRODUCTION
The effects assessment comprises the following steps of the risk assessment procedure:
EFFECTS ASSESSMENT
• hazard identification: The aim of the hazard identification is to identify the effects of
concern. For existing substances and biocidal active substances and substances of concern in
biocidal products, the aim is also to review the classification of the substance while for new
substances a proposal on classification is done;
• dose (concentration) - response (effect) assessment: At this step the predicted no effect
concentration (PNEC), shall, where possible, be determined.
For both steps of the effects assessment it is of high importance to evaluate the data with regard
to their adequacy and completeness. The evaluation of adequacy shall address the quality and
relevance of data (see Section 3.2). The evaluation of data is of particular importance for existing
substances as tests will often be available with non-standard organisms and/or non-standardised
methods. It is suitable to start the effects assessment process with the evaluation of the available
ecotoxicological data.
As stated in Section 1.2, the environmental compartments considered for the inland environment
are the aquatic and terrestrial ecosystem, top predators, microbial activity in a STP, and the
atmosphere. This means that for each of these compartments a PNEC has to be derived. A PNEC
is regarded as a concentration below which an unacceptable effect will most likely not occur. In
principle, the PNEC is calculated by dividing the lowest short-term L(E)C50 or long-term NOEC
value by an appropriate assessment factor. The assessment factors reflect the degree of
uncertainty in extrapolation from laboratory toxicity test data for a limited number of species to
the 'real' environment. Assessment factors applied for long-term tests are smaller as the
uncertainty of the extrapolation from laboratory data to the natural environment is reduced. For
this reason long-term data are preferred to short-term data.
A detailed assessment of the environmental risk is often only feasible for the water compartment:
for new substances the base-set consists of effect data for aquatic organisms only, while for
existing substances most of the available data will be for aquatic organisms. For biocides, the
core data set comprises effect data on aquatic organisms as well. Therefore, a more detailed
description on deriving a PNECwater is described in Section 3.3. For an intermittent release of
substances, aquatic organisms may be exposed for only a short period. In these cases, short-term
L(E)C50 values are used to derive a PNECwater, intermittent. This is described in Section 3.3.2.
The microbial activity in domestic and industrial STPs may be affected. Assessment factors to
derive a PNECmicroorganisms are given in Section 3.4.
Probably for most compounds no data will be present for sediment-dwelling organisms.
Appropriate test systems and standardised guidelines are still under development. The
equilibrium partitioning method is proposed as a screening method for derivation of a PNECsed
to compensate for this lack of toxicity data. If sediment test results are available, the PNECsed is
derived from these data by applying assessment factors (see Section 3.5).
Few toxicity data are also available for the soil compartment. Where such data are present, they
will normally include only test results from short-term studies. If test data are lacking, the
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