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Importance of surface run off as a route of aquatic exposure to pesticides in the UK - PS2233

Description
Spray drift, drainflow and surface runoff can all contribute to the transport of pesticides to surface waters. Spray drift and drainflow are known to be important and extensive for the UK. Regulatory calculations that are specific to the UK have been implemented over many years (e.g. the UK drainflow calculation based on experiments at Brimstone Farm) and these have recently been supplemented with pan-European tools introduced as the FOCUS surface water scenarios [1]. However, the importance of surface runoff as a route of exposure in the UK is not known.

Surface runoff has often been regarded as more localised in extent and may be subject to controls such as vegetated buffer zones that are imposed by other drivers, such as actions to control transfer of phosphate to surface waters. A study undertaken in the 1990’s investigated particulate transport of pesticides and showed that there is significant potential for in-field transport of pesticides via surface runoff (both dissolved and particulate phases) [PL0505; 2]. Nevertheless, the project focused on in-field measurements, and the extent to which pesticides are subsequently exported to the receiving water remains unknown. As a consequence, the relative importance of surface runoff for aquatic exposure is not known and it is not clear how predictions of exposure via runoff from FOCUS should be treated within national registration procedures.

The aim of this study is to establish the relative importance of surface runoff as a route of aquatic exposure to pesticides in the UK and to propose robust approaches to incorporate runoff predictions from FOCUS into national regulatory procedures.
Objective
1. Review the current literature for (i) measurements of pesticide concentrations in surface runoff, (ii) evidence relevant to UK conditions of effectiveness of runoff mitigation techniques, and (iii) models that might be used to simulate pesticide transport in surface runoff.

2. Conduct a national surface water vulnerability assessment by relating crop, slope and water body characteristics to soils that are susceptible to runoff and then to investigate field-level vulnerability to surface runoff within areas with the greatest risk of pesticide contamination.

3. Undertake an initial quantification for levels of pesticides contained in runoff for sites in the UK representing different crop and soil types.

4. Test the ability of the PRZM model and alternative approaches identified in Objective 1 to predict pesticide concentrations moving to surface waters in the UK.

5. Assess the relative importance of surface runoff as a route of exposure compared to spray drift and drainflow and recommend to PSD how aquatic exposure via surface runoff could be considered within UK regulatory procedures.
Project Documents
• Final Report - Annex : Importance of surface runoff as a route of aquatic exposure to pesticides in the UK - appendix 1   (1748k)
• Final Report - Annex : Importance of surface runoff as a route of aquatic exposure to pesticides in the UK - appendix 2   (7188k)
• Final Report - Annex : Importance of surface runoff as a route of aquatic exposure to pesticides in the UK - appendix 3   (893k)
• Final Report - Annex : Importance of surface runoff as a route of aquatic exposure to pesticides in the UK - appendix 4   (375k)
• Final Report - SID5A : Importance of surface runoff as a route of aquatic exposure to pesticides in the UK   (693k)
Time-Scale and Cost
From: 2007

To: 2009

Cost: £206,847
Contractor / Funded Organisations
University - York, ADAS UK Ltd.
Keywords
Agricultural Land              
Decision Support Tools              
Environmental Effects              
Environmental Impacts              
Modelling              
Pest and Weed Control              
Pesticide use              
Pesticides              
Plants and Animals              
Water              
Fields of Study
Pesticide Safety