ESCORT 2 - View of the Advisory Committee on Pesticides Environmental Panel
Introduction
On 31 January and 6 June 2002, the Environmental Panel of the Advisory Committee on Pesticides (ACP) discussed the risk assessment for non-target arthropods in the context of 91/414/EEC (now regulation 1107/2009 as it applies in Great Britain and Northern Ireland). More specifically, they discussed the proceedings from European Standard Characteristics of Non-Target Arthropod Regulatory Testing (ESCORT 2) and how this proposed new approach could be incorporated into regulatory risk assessment. Outlined below is the Environmental Panel's opinion of ESCORT 2.
(NB: The following is not intended to be a definitive guide on how to assess the risk to non-target arthropods. It should, however, be read alongside ESCORT 2).
General issues
A fundamental difference between ESCORT 2 and the previous approach to non-target arthropod risk assessment is the separate consideration of effects in-field and off-field. The Environmental Panel welcomed this new approach and agreed that, where appropriate risk assessments should be carried out for both in-field and off-field scenarios. The Environmental Panel acknowledged that this risk assessment approach was only for spray applications.
The Environmental Panel agreed with the proposal that testing of insect growth regulators, or other plant protection products with special modes of action, should focus on those stages of non-target arthropods likely to demonstrate effects (eg juvenile stages), and should also take account of the appropriate routes of uptake. As regards granular formulation and seed treatments, the workshop proposed that this area of risk assessment should be developed by the European Plant Protection Organisation (EPPO) soil organism group.
Tier 1
The Environmental Panel noted that Tier 1 data are generated by exposing Aphidius rhopalosiphi and Typhlodromus pyri to fresh residues applied to glass plates. The Environmental Panel highlighted that these species were predominantly 'integrated pest management' Integrated Pest Management (IPM) species. Due to this there was concern over whether these species are truly representative of all those species occurring in-field. As regards extrapolating effects on these species to species that occur off-field, the Environmental Panel noted that due to this concern, ESCORT 2 had proposed an uncertainty factor of 10 for the off-field assessment (see Equation 2 in ESCORT 2). It was appreciated that this figure was arbitrary and the Environmental Panel concluded that it was difficult to confirm whether it was appropriate. However, in the absence of further data, they considered it to be reasonable.
The Environmental Panel discussed whether a hazard quotient (HQ) of 2 was appropriate for both in- and off-field assessments. Work conducted by the Environmental Panel indicated that the percentage chance of not identifying a harmful compound was 1 to 2.5% based on data for T. pyri, and 5 to 10% based on data for Aphidius spp. Considering that further assessment was required when only one species was affected, the Environmental Panel considered that a HQ of 2 was appropriate.
The use of a 'multiple application factor' (MAF) to reflect multiple applications was considered to be an acceptable approach.
Tier 2
In-field assessment
The Environmental Panel concluded that, if concern is raised as a result of a Tier 1 in-field assessment (ie the HQ is >2, for one or more species), then appropriate data should always be submitted in order to ensure that potential impacts are acceptable. In indicating acceptability of in-field effects, it may be appropriate to use aged-residue studies to indicate the potential for recovery. However, the Environmental Panel highlighted that their use and subsequent interpretation was important to ensure that correct conclusions were drawn regarding recovery. Alternatively, other higher tier studies, eg extended laboratory, semi-field and field studies, may be used to indicate acceptability of effects (see below).
Off-field assessment
As regards carrying out the off-field assessment, the Environmental Panel concluded that initial default distances of 1m and 3m for arable and orchard scenarios respectively should always be used. It may be appropriate to carry out an off-crop assessment at additional distances, if this is considered appropriate (see below).
For higher tier risk assessment, the Environmental Panel concluded that if as a result of the Tier 1 off-field risk assessment concern is raised (ie the HQ is >2 for one or more of the species tested), then higher tier data should always be submitted. It was noted that the higher tier data may be generated at application rates equivalent to the appropriate default distances of 1m or 3m, or at suitable distances, if appropriate. For example, if concern has been raised regarding the use of a product on cereals, then it would be appropriate to carry out higher tier assessments at the drift rate at 1m and 6m.
Higher tier studies
As regards extended laboratory studies and semi-field studies, it was noted by the Environmental Panel that a 50% effect level was proposed as the trigger value. The Environmental Panel appreciated that this value was a practical endpoint rather than an ecologically relevant endpoint. They acknowledged that this was due to the generally poor sensitivity of the experimental design for such studies, and they considered that the design of such studies should be improved, so that statistically significant differences could be detected at lower, more ecologically relevant effects levels. However, in the absence of further data, they accepted that this was an appropriate trigger value.
When determining the appropriate exposure level for higher tier studies to determine the risk in- and off-field, ESCORT 2 proposes the following equations (see page 19 ESCORT 2);
Field rate =
The Environmental Panel considered this to be appropriate for the in-field calculation and agreed with the use of the MAF. The Environmental Panel proposed that for the off-crop drift calculation, the 'vegetation distribution factor' should be as outlined in ESCORT 2, ie 10. It should be noted, that depending upon the test, this factor may not be relevant (see ESCORT 2 for details). However, they considered that due to the uncertainty regarding off-crop species, a higher uncertainty factor should be used. Therefore, they proposed that a correction factor of 10 should be used to account for uncertainty in sensitivity of species. It should be noted that this issue is only relevant for extended laboratory and semi-field studies but not for field studies.
Acceptability of effects
On the issue of recovery and acceptability of effects in-field for the arable situation, the Environmental Panel agreed that "recovery within season" should be adopted as a working definition of acceptability. However, it was accepted that recovery, or potential for recovery, should be assessed on a case-by-case basis, hence it would be important to consider the biology and ecology of the species concerned as well as the crop treated. If recovery was not observed within a season, this did not automatically preclude approval. In these instances, the use of risk management measures should be considered before concluding whether a use is acceptable or not.
As regards orchards and similar situations, it was concluded that the issues were slightly different to arable crops, hence it would be necessary to demonstrate the potential for re-colonisation, which could be done via the use of aged residues studies.
For off-crop effects, the definition proposed by ESCORT 2, ie the potential for re-colonisation within an ecologically relevant time, was accepted.
For hand-held and home garden uses, it was concluded that due to the small scale of use and hence localised nature of any impact, that no assessment for non-target arthropods is required. However, appropriate labelling may be required.
Conclusion
The Environmental Panel concluded that, subject to the above points, ESCORT 2 was a welcome development and, where appropriate, the assessment of non-target arthropods should be carried out according to ESCORT 2.
The Environmental Panel did however feel that there were key areas which should be considered further in future developments of non-target arthropod risk assessment. These areas included:
- improvement of higher tier study design so that the endpoint is both statistically and ecologically robust
- work to determine the relevance of the test species to non-target arthropods which occur off-field, and
- clarification of an appropriate 'vegetation distribution factor'
The above views will be taken into account when the risk to non-target arthropods is considered under 91/414/EEC (now regulation 1107/2009 as it applies in Great Britain and Northern Ireland).
Guidance Document on Regulatory Testing and Risk Assessment Procedures for Plant Protection Products with Non-Target Arthropods. From the ESCORT 2 Workshop (European Standard Characteristics of Non-Target Arthropod Regulatory Testing). Ed: MP Candolfi, KL Barrett, PJ Campbell, R Forster, N Grandy, M-C Huet, G Lewis, PA Oomen, R Schmuck, H Vogt. Copies of this publication are available from SETAC-Europe (www.setac.org)