Commission Regulation (EC) No 429/2008Show full title

3.4.2. Phase II assessment

The aim of Phase II is to assess the potential for additives to affect non-target species in the environment, including both aquatic and terrestrial species or to reach groundwater at unacceptable levels. It is not practical to evaluate the effects of additives on every species in the environment that may be exposed to the additive following its administration to the target species. The taxonomic levels tested are intended to serve as surrogates or indicators for the range of species present in the environment.

The Phase II assessment is based on a risk quotient approach, where the calculated PEC and Predicted No Effect Concentration (PNEC) values for each compartment shall be compared. The PNEC is determined from experimentally determined endpoints divided by an appropriate assessment factor. The PNEC value shall be calculated for each compartment.

The Phase II assessment starts with a refinement of the PEC if possible, and uses a two-tiered approach to the environmental risk assessment.

The first tier, Phase IIA, makes use of a limited number of fate and effect studies to produce a conservative assessment of risk based on exposure and effects in the environmental compartment of concern. If the ratio of the PEC to the PNEC is lower than one (1), no further assessment is required, unless bioaccumulation is expected.

If the PEC/PNEC ratio predicts an unacceptable risk (ratio > 1), the applicant shall progress to Phase IIB to refine the environmental risk assessment.

3.4.2.1. Phase II A

In addition to the compartments considered in Phase I, the PEC for surface water has to be calculated considering runoff and drainage.

Based on data not considered in Phase I, a more refined PEC can be calculated for each environmental compartment of concern. In ascertaining the refined PEC, account shall be taken of:

(a)

the concentration of active substance(s)/metabolites of concern in manure/fish faeces following administration of the additive to animals at the proposed dose level. This calculation shall include consideration of dosage rates and amount of excreta produced;

(b)

the potential degradation of the excreted active substance(s)/metabolites of concern during normal manure processing practice and storage prior to its application to land;

(c)

the adsorption/desorption of the active substance(s)/metabolites of concern onto soil or sediment for aquaculture, preferentially determined by studies in soil/sediment (OECD 106);

(d)

degradation in soil and water/sediment systems (OECD 307 and 308, respectively); and

(e)

other factors such as hydrolysis, photolysis, evaporation, dilution through ploughing.

The highest value for the PEC obtained from these calculations for each environmental compartment of concern shall be adopted for Phase II risk assessment purposes.

If a high persistence in soil/sediment is anticipated (time to degradation of 90 % of original concentration of the compound: DT₉₀ > 1 year), the potential for accumulation shall be considered.

The concentrations of additives (or metabolites) producing serious adverse effects for various trophic levels in the environmental compartments of concern shall be determined. These tests are mostly acute tests and should follow OECD or similar well-established guidelines. Studies for the terrestrial environment shall include: toxicity to earthworms; three terrestrial plants; and soil micro-organisms (e.g. effects on nitrogen fixation). Studies for the fresh water environment shall include: toxicity to fish; Daphnia magna; algae; and a sediment dwelling organism. In case of sea cages, three species of different taxa of sediment dwelling organisms shall be studied.

Calculation of the PNEC value shall be carried out for each compartment of concern. The PNEC is normally derived from the lowest toxicity value observed in the above tests and dividing by a safety factor of at least 100 depending on the endpoint and number of test species used.

The potential for bioaccumulation can be estimated from the value of the n-octanol/water partition coefficient, Log K_ow. Values ≥ 3 indicate that the substance may bioaccumulated. In order to assess the risk for secondary poisoning it shall be considered whether to carry out a bioconcentration factor (BCF) study at Phase IIB.

3.4.2.2. Phase IIB (more detailed ecotoxicological studies)

For those additives where, following Phase IIA assessment, an environmental risk cannot be excluded, more information is required on the effects on biological species in the environmental compartment(s) in which Phase IIA studies indicate possible concern. In this situation, further tests are needed to determine the chronic and more specific effects on appropriate microbial, plant, and animal species. This additional information will allow the application a lower safety factor.

Suitable additional ecotoxicity tests are described in a number of publications, e.g. in OECD Guidelines. Careful choice of such tests is necessary to ensure that they are appropriate to the situation in which the additive and/or its metabolites may be released and dispersed in the environment. The refinement of the effect assessment for soil (PNEC_soil) could be based on studies on the chronic effects on earthworms, additional studies on soil microflora and a number of relevant plant species, studies on grassland invertebrates (including insects) and feral birds.

The refinement of the effect assessment for water/sediment could be based on chronic toxicity tests on the most sensitive aquatic/benthic organisms identified in Phase IIA assessment.

Bioaccumulation studies, if necessary, should be performed according to OECD Guideline 305.