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Particulate transport of pesticide residues - PL0505

In response to a need to improve natural water quality (including to meet the EC Directive for Drinking Water) there is a requirement to minimise pesticide residues loss to surface waters. Residues of some pesticides applied to agricultural land contaminate surface waters directly, either through surface runoff or by sub-surface drainflow. Other pesticides are transported to surface waters bonded to particulate matter.

Recent MAFF funded studies at both the field and catchment scale have identified the magnitude of the problem of pesticide residue loss from agricultural soils. Although losses are often equivalent to less than 1% of that applied, concentrations can be well in excess of the Drinking Water Directive MAC for potable water during runoff events. Information on the processes that will control pesticide movement and factors that influence this movement remain limited. New MAFF funded research at the Brimstone Farm site (ROAMES PL0501, PL0502, PL0503) are addressing this aspect. Measures are to be developed specifically to influence the interaction of the surface/cultivated layer under arable cropping so as to reduce the movement of pesticides to the drainage system. Future work may also determine the partitioning of pesticides transported in the water/suspended sediment phase in drainage waters.

However, although some data on the loss of pesticides in sediment is available, information is limited and little is known about the consequent possible re-distribution of pesticides carried in this transport process at the catchment scale. In addition, information on possible measures to control this contamination, eg. by using buffer zones or other barrier systems, is very limited.

The aim of this project is to monitor the factors controlling the mode of transport of several pesticides with a range of different physico-chemical properties, especially the significance of particulate transport at the small catchment scale.

The project will be undertaken in four phases, to maximise on the funding available, with phase I established as a scoping study to specifically compare pesticide transport in surface runoff with that in drainage water, and to identify the amount of particulate transport under storm runoff conditions. This first phase will include pilot field scope studies to support the catchment approach at one site (Rosemaund). At the second site, (Trent), emphasis will be placed on the assessment of the catchment farming systems and the determination of particulates in streamwater.

During the first year a strategy will be established to develop an ADAS led collaborative programme, and if appropriate a multi-funded approach to the work, so that in later years the field scale processes can be linked to the processes operating in the stream/river system. The collaboration would consider potential IFE and SSLRC expertise to support the studies.

In phase II the specific field-scale soil-hydrology and stream/river-scale processes operating would be addressed so as to be able to identify, implement and evaluate appropriate agricultural control measures, eg buffers to reduce the contamination of water courses.

The implementation of a control/buffer approach in Phase II should be undertaken at the same time as a linkage with other appropriate UK databases is initiated. This will provide the framework for modelling studies in Phase III to widen the benefits from this study. This should include modelling of the field and stream processes operating and should be developed in Phase IV to provide a GIS based package to identify agricultural areas where the recommended controlling measures would be effective. The results from this study will address the PSD Policy Objective of developing farming systems which minimise the migration of pesticides into surface water.
Overall objective

To identify the key processes at the field and catchment scale controlling the transport of pesticides on particulate matter. To develop and evaluate appropriate agricultural management practices (eg buffers) to reduce the risk of loss of pesticides to natural waters and to provide guidelines for the effective use of these management practices or control measures as part of a farm-scale agricultural programme.

Identifier Sites Objectives Start Completion
Date Dates
PHASE I Rosemaund 1. To establish field scale Jul. Dec.
Trent and catchment based 1993 1997
studies to compare the
transport of pesticides in
surface runoff and in
drainage waters.

2. To develop a suitable
sampling approach to
determine the movement of
pesticides in river systems
and identify the impact
on the aquatic environment.

PHASE II To determine the field Apr. Dec.
scale soil-hydrology 1994 1997
processes influencing the
mode for pesticide transport
and to identify appropriate
agricultural control
measures (eg buffers).

PHASE III To develop through Apr. Mar.
modelling studies, 1995 1998
basic guidelines on the
appropriate measures to
minimise the migration of
pesticides to surface

PHASE IV To provide PSD with Apr. Mar.
recommended control 1997 1998
measures incorporated
into a GIS based package
to reduce the migration
of pesticides to surface
Project Documents
• Final Report : Particulate transport of pesticide residues   (207k)
Time-Scale and Cost
From: 1993

To: 1998

Cost: £728,619
Contractor / Funded Organisations
Fields of Study
Pesticide Safety