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The Applicant Guide: Reduced water volume: Operator and Efficacy/Crops Safety Risk Assessments

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This page sets out the procedures and data required to support changes to plant protection product labels, to reflect use in reduced water volumes. It is common commercial practice that end users, for practical and economic reasons, apply product in a volume of water less than that specified on the current label (thus applying the product at an increased concentration). Cross compliance inspections by the Rural Payments Agency (RPA) raised significant anxieties for industry whether, and to what extent, the volume of water stated on labels could be reduced. HSE's Chemicals Regulation Division (CRD) emphasised the need to follow the guidance in the Code of Practice and also issued a Q and A (in Reg Update 15/2007) on some specific issues. To make the position quite clear with respect to individual products, product labels should recommend a range of water volumes in which the product can be safely applied. This can be done by making an application for a label change to CRD.

How to Apply

Applications to reduce the minimum water volume on the label must include an operator exposure assessment and data, or a case addressing efficacy (see below). They should be submitted to CRD, where they will be assessed via the data or data plus stream and attract an appropriate fee, depending on how many data modules are required.

Such applications will be allowed as an exception under the transitional arrangements between national and EU legislation. If acceptable, new authorisations will be issued stipulating the minimum water volume, and label amendments specified to reflect this.

Operator Risk Assessments

Standard risk assessment methods should be used (eg UK Predictive Operator Exposure Model (POEM)). These should demonstrate that use with reduced water volumes does not pose an unacceptable risk.

Efficacy and Crop Safety Assessment

Data, or a case based on data, confirming adequate efficacy and comparable crop safety must be provided to justify the proposed reduction in water volume. Data from the public domain may be used subject to its relevance (see note below *).

There may be instances where efficacy/crop safety data are not available to support changes in water volume. As long as a case for reduced water volume is made by the applicant we will evaluate the operator exposure assessment and consider granting a 'qualified authorisation*' for the reduced volume recommendation. Label text would be required to indicate that efficacy data to support reduced volume have not been provided. This would remain a 'qualified authorisation' until data were provided to support a 'full' authorisation.

Applicants should note that there are situations (depending on the mode of action, crop and target; (see note below †) where reduced water volume spray applications may not be appropriate, since they raise concerns over effectiveness. Examples include uses such as:

Whilst data may be used to support recommendations for reduced water volumes for such uses, CRD would not authorise such recommendations in the absence of appropriate data.

Further information:

* Further information on qualified recommendations can be found in  Efficacy guidelines in Data Requirements .Applicants should note that recent public domain evidence in the form of an HGCA report titled 'Spray behaviour and efficacy of herbicides and fungicides applied to wheat at reduced volumes' is available on the Home-Grown Cereals Authority (HGCA) website. Whilst this report concludes that water volumes did not influence efficacy in the studies conducted, it also indicates that there are some fundamental reasons why low volumes may result in poorer pesticide performance. Simple reference to this report, therefore, is insufficient evidence for blanket reductions in water volume and applicants should consider and address the specific uses for which reduced application volumes are sought.


Updated 2020-11-06