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

3.4. Studies concerning the safety of use of the additive for the environment

Consideration of the environmental impact of additives is important since administration of additives typically occurs over long periods, often involves large groups of animals and the active substance(s) may be excreted to a considerable extent either as the parent compound or its metabolites.

To determine the environmental impact of additives, a stepwise approach shall be followed. All additives have to be assessed through Phase I to identify those additives which do not need further testing. For the other additives a second phase (Phase II) assessment is needed to provide additional information, based upon which further studies may be considered necessary. These studies shall be conducted according to Directive 67/548/EEC.

3.4.1. Phase I assessment

The purpose of Phase I assessment is to determine if a significant environmental effect of the additive or its metabolites is likely and whether a Phase II assessment is necessary (see decision tree).

Exemption from Phase II assessment may be made on one of two criteria, unless there is scientifically-based evidence for concern:

(a)

the chemical nature and the biological effect of the additive and its conditions of use indicate that impact will be negligible, i.e. where the additive is:

• a physiological or natural substance that will not result in a substantial increase of the concentration in the environment; or

• intended for non-food producing animals;

(b)

the worst case Predicted Environmental Concentration (PEC) is too low to be of concern. The PEC shall be evaluated for each compartment of concern (see below), assuming that 100 % of the dose ingested is excreted as the parent compound.

If the applicant cannot demonstrate that the additive falls into one of these exemption categories, a Phase II assessment will be required.

3.4.1.1. Additives for terrestrial animals

When excreta from livestock are applied on land, the use of feed additives can lead to contamination of soil, ground water, and surface water (via drainage and run-off).

The worst case PEC for soil (PEC_soil) would arise considering all excreted compounds being spread on land. If the PEC_soil (default: 5 cm depth) is less than 10 μg/kg, no further assessment is required.

If the PEC for contamination of groundwater (PEC_gw) is less than 0,1 μg/l, no Phase II assessment of the environmental impact of the additive on groundwater is necessary.

3.4.1.2. Additives for aquatic animals

Feed additives used in aquaculture can result in contamination of sediment and water. The compartment of concern for the environmental risk assessment for fish farmed in cages is assumed to be the sediment. For fish farmed in land-based systems the effluent flowing to surface water is considered to pose the major environmental risk.

The worst case PEC for sediment (PEC_sediment) would arise considering all excreted compounds being deposited in the sediment. If the PEC_sediment (default: 20 cm depth) is less than 10 μg/kg wet weight, then no further assessment is required.

If the PEC in the surface water (PEC_sw) is less than 0,1 μg/l, no further assessment is required.

Phase I — Decision tree

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.