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Options for the development of a model for evaluation of bystander & resident exposures to pesticides used in orchard, hops & bush fruit applications - PS2024

Description
The recently completed BREAM project has developed an exposure assessment model for bystanders and residents from pesticides used in agricultural boom sprayer operations. There is a concern that the applications to top fruit may result in significantly higher risks for bystanders and residents because of the type of crop and the equipment used to spray it. While boom applications account for the majority of pesticide applications in UK agriculture (for instance the Pesticide Usage statistics for 2006 suggest a total treated area of 58 million ha, with 40.6 million to cereals and oilseeds and only 600 thousand ha to top fruit and hops), much of the top fruit area in the UK is in relatively highly popuated areas and the probability of bystander or resident exposure could be higher and an exposure assessment has to take account of this.

The BREAM model used an existing drift modelling approach, combined with empirical data to map airborne spray to bystander contamination, with a probabilistic element to take account of some of the sources of variablility. While a similar approach could be taken for tree and bush fruit spraying, there are some significant differences in terms of the range of different machines and operating conditions, field layouts, crop structures and sources of variability that could be problematic. There are other modelling approaches that have been taken specifically for orchards and fruit plantations which should also be considered before making a decision about the best way forward.

The data available for both development and validation of the model is crucial. It is likely that there is very little data, apart from the original Lloyd et al (1987) report, relating to bystander contamination, and the majority of published results are likely to be ground deposits obtained in order to investigate losses to surface water. A review of the available data, in order to determine gaps, will be necessary.

The results of the BREAM project showed that the 'bystander scenario' - i.e. the location of the bystander/resident, and the duration of their exposure - are crucial to predicted exposures. The same is likely to be true of orchard spraying, but the 'reasonable worst case' which needs to be included in the model is difficult to define without some knowledge of typical orchard layouts and the potential proximity of bystanders or residents to the field edge.
This project therefore aims to investigate current practice in tree, hop and bush fruit spraying and management and review the current scientific knowledge of spray drift from broadcast air-assisted sprayers used for foliar spray applications to tree and bush fruit in order to propose an appropriate modelling and experimental approach to the development of a new exposure assessment for bystanders and residents. Specific objectives include:
An informal survey of growers to establish relevant information about (a) their application machinery and the way it is used and (b) the layout of orchards, hop gardens and fruit plantations
Use of available mapping systems to determine bystander scenarios and resident proximity
A review of modelling approaches for spray drift from broadcast air-assisted fruit sprayers
A review of orchard and fruit plantation spray drift data and bystander contamination data that is available
An analysis of the options for development of a bystander and resident exposure model for orchards, hop gardens and bush fruit plantations

The outcome of the project will be a proposal for the way forward in developing BREAM for orchards, hop gardens and bush fruit plantations
Objective
1. An informal survey of growers to establish relevant information about (a) their application machinery and the way it is used and (b) the layout of orchards, hop gardens and bush fruit plantations (including raspberry crops which are mainly grown in polythene tunnels)
2. Use of available mapping systems to determine bystander scenarios and resident proximity
3. A review of modelling approaches for spray drift from broadcast air-assisted sprayers
4. A review of orchard, hop and fruit plantation spray drift data and bystander contamination data that is available
5. An analysis of the options for development of a bystander and resident exposure model for orchards, hop gardens and bush fruit plantations
Project Documents
• EVID4 - Final project report : PS2024 final report   (666k)
Time-Scale and Cost
From: 2010

To: 2011

Cost: £44,597
Contractor / Funded Organisations
East Malling Ltd, The Arable Group
Keywords
Agriculture              
Application              
Chemicals              
Crops              
Environment              
Environmental Protection              
Health Effects              
Hops              
Modelling              
Pesticides              
Pollution              
Fields of Study
Pesticide Safety