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6 TESTING STRATEGIES
6.1 INTRODUCTION
TESTING STRATEGIES
In this chapter testing strategies for PEC and PNEC are given that are in principle to be followed
when the conclusion of the risk characterisation phase is that there is concern and there is a need
to ask for further information to refine the risk assessment. As has been mentioned in the
previous chapter a decision has to be made as to whether PEC, PNEC or both need to be revised.
This decision by the competent authority must be transparent and justified and should be based
on the principles of lowest cost and effort, highest gain of information and the avoidance of
unnecessary testing of animals.
Separate from the testing strategies that need to be followed when risks are identified, the PBT
assessment as described in Section 4.4 may identify the need for further information to clarify
the potential PBT (Persistent, Bioaccumulative, Toxic) or vPvB (very Persistent, very
Bioaccumulative) properties of a substance. When such testing is requested, and the substance
turns out not to fulfil the PBT or vPvB criteria, the test results should be used in the subsequent
PEC/PNEC calculations.
6.2 REFINEMENT OF PEC
In order to refine the PEC, in addition to comprehensive information on production and
application, additional tests may lead to a better quantification of the elimination processes of a
substance in the individual environmental compartments or in the sewage treatment plant. The
exact degree of elimination may be determined by measurements in the influent and effluent of
sewage treatment plants or by conducting appropriate tests on the degradation behaviour.
The testing strategy for biocides can be found in the Technical Notes for Guidance for
Directive 98/8” (TNsG on Data Requirements, 2000, Chapter 3, Section 7.0.2, available on
http://ecb.jrc.it/biocides/). This strategy could also be employed on substances, which potentially
may meet the persistency criteria for PBTs. The kind of simulation test asked for should depend
on the compartment of highest concern. If the sediment compartment turns out to be the
compartment of highest concern, it could be decided to continue with a sediment simulation test
depending on the physico-chemical properties of the substance as defined in the biocides testing
strategy.
Furthermore it should be noted that a guidance document on how to assess and test relevant
metabolites and transformation products is under preparation for plant protection products under
Directive 91/414. This document could be modified later for use for biocides, and where
appropriate for new and existing substances.
Guidance in relation to further degradation studies when refining the PEC for STP or one or
more of the environmental compartments is given below. In general simulation tests should be
considered based on the likelihood for such test data to actually refine the PEC(s) in a way that
may influence the ultimate result of the risk assessment (see Section 2.3.1, sensitivity analysis).
Similarly, the experimental determination of the BCF can be requested in order to refine the
PECoral for secondary poisoning (see Section 3.8).
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