What is LERAP?

Dr Colin Mumford in Chemicals & Fertilisers

Not to be confused with the French hip-hop scene, LERAP is the protocol relating to a buffer zone between a body of water and an area being treated with a pesticide. Dr Colin Mumford, Bayer CropScience's technical support specialist, explains everything you need to know

LERAP stands for Local Environmental Risk Assessment for Pesticides and is easily carried out using a standard pro-forma (see Table 1). A LERAP is undertaken when using a horizontal boom sprayer with LERAP applicable pesticides. Its purpose is to ensure that there is an area of untreated ground, often referred to as a 'buffer zone', between an area treated with a pesticide and a body of water, which can be either static or flowing, such as a lake or river. Not all pesticides are subject to a LERAP. If a LERAP is required, it will be clearly stated on the pesticide's label with a logo.

Why it is in place?

The buffer zone helps minimise issues such as surface runoff or accidental direct application of a pesticide into a body of water. Runoff, or direct application, may pollute the water or affect the local environment so that it becomes harmful to wildlife, both in and around the body of water. The LERAP is concerned with the minimum acceptable distance between the target area and the top of the bank of any adjacent ditch or body of water. This is often referred to as the 'width' of the buffer zone.

Interim update to aquatic buffer zone scheme for plant protection products


ntil relatively recently, there were only two categories of LERAP; category A and category B. These categories are being phased out but are still in use at the moment, and some products will continue to carry the category A or category B classification for some time.

In October 2011, an interim scheme was introduced that enabled the use of buffer zones that are greater than five metres from ponds, ditches and other bodies of water (see Table 2). Although the scheme is intended mostly for crop growers, it is still applicable to sports turf management.

Since the scheme was introduced, Plant Protection Products assessed by the Chemicals Regulation Directorate (CRD) are no longer categorised as A or B. Now, if a buffer zone is required for a given crop, it will be stated clearly on the products label. The label information will also state whether or not a reduction in the size of the buffer zone is possible by undertaking a LERAP reduction assessment, similar to the category B rating.

The different levels of LERAP (A and B)

As the older categories are still in existence, and may be for some time, it is essential that you know the difference between the two categories. Category A covers products that must not be applied within five metres of the bank of a body of water with a horizontal boom sprayer. However, where the product is to be applied near to a ditch that is dry at the time of application, the distance can be reduced to one metre from the top of the ditch.

With category B products, however, it is possible to reduce the width of the buffer zone, as long as a LERAP assessment is carried out and shows that no damaging or harmful effects will arise as a result of reducing the buffer zone width. Furthermore, for Category B pesticides, if a reduction in the width of the buffer zone is intended, a LERAP must be carried out each time an area is to be

treated with a given product in accordance with the CRD published guidance. If the buffer zone is maintained, however, a LERAP does not need to be completed at every application event.

How adjustments can be made to reduce buffer widths

If a product is a Category B product, or has a newer label stating that the buffer zone can be reduced after undertaking a LERAP, there are a few things you can do to reduce the buffer zone.

The type of nozzle you use is the biggest factor in establishing buffer zone sizes. The nozzles should be CRD recognised LERAP low-drift status nozzles. These are divided into three different star ratings; one star, two stars, and three stars. The difference between the nozzles is the drift performance, measurable as a ground deposit.

The performance of the nozzles is compared to drift levels from a reference system. The reference system is an open structured boom manufactured from stainless steel and fitted with F110/1.2/3.0 nozzles, operating with a nozzle height of 0.5 m above the target. The reference performance is based on spraying water and a 0.1% solution of non-ionic surfactant (wetting agent).

- Nozzles without a LERAP low-drift rating have drift levels greater than 75% of the reference system
- One star nozzles have drift levels between 50 and 75% of the reference value
- Two star nozzles have drift levels greater than 25% and up to 50% of the reference value
- Three star nozzles have drift values up to 25% of the reference value

Therefore, the amount of drift can be significantly reduced with the use of an appropriate nozzle. Spray equipment not formally recognised by CRD as having 'LERAP - low drift status,' should be considered as a 'standard reference sprayer,' irrespective of any manufacturer's claims.

If the product being applied allows the use of a hand held sprayer, the use of a hand held lance, either connected to your main sprayer or a knapsack, can be used to reduce the width of the buffer zone. However, it is not permitted to let direct spray from hand held sprayers to fall within one metre of the bank of a static or flowing body of water. In addition, the spray must be directed away from the bank and body of water.

If the LERAP has been carried out by someone other than the person who will operate the sprayer, they must ensure the operator knows the width of the buffer zone that will be left untreated. It is always a good idea to keep a written record of this information hand-over on the LERAP pro-forma.

Not all products carry a LERAP, but the application of all pesticides near to a water course should be applied in accordance with good practice guidelines, which means carrying out a risk assessment to identify any potential hazards to the local environment, wildlife, waterway or otherwise. Always read the labels before you start the spraying process.