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Protecting Water in Europe

Risks to water from agriculture

 The risk to water from agriculture mainly comes from:

  • Soil erosion; sediment and nutrients can cause damage to aquatic habitats and;
  • Leaching and run-off of agrochemicals and nutrients into ground and surface water; which can cause damage to water both as a habitat and a resource

Training operators to prevent point source pollution - TOPPS project

The TOPPS project focussed on the latter – specifically on how to prevent pesticides reaching the water.  Some studies suggest “that between 40% and 95% of plant protection products (PPPs) found in water originated from point sources”. Accepting these figures, The TOPPS project also recognised that the way pesticides reach the water is most often because of human error:

An important fact is that point sources can contribute significantly to the overall quantities of pesticides found in water and in this respect the individual behaviour of pesticide users often has more practical impact than the amounts and properties of the pesticides used." (

Drivers for Change 

The European Unions's (EU) Water Framework Directive, introduced in 2000 has an overall objective of “achieving a ‘good status’ for all waters” by 2015 where: 

“Good chemical status is defined in terms of compliance with all the quality standards established for chemical substances at European level.”

The concern is that failure to comply with the EU legislation - or exceeding the current threshold of 0.1 µg/l in drinking water1 - will result in the loss of some PPPs thus reducing the range of pesticides available for farmers to use on their crops.

Preventing Point Source Pollution - Changing Behaviours

One of the  six tasks  which the TOPPS project set itself on inception in 2005, thus included researching current practice and developing a set of "Best Management Practices" (BMPs) . These BMPs are designed to encourage changes in behaviour and focus “on avoiding point source contamination by professional agricultural PPPs users”.

Whilst the project is European and the focus on PPP users in agriculture, the principles can be applied globally and in many situations. The TOPPS BMPs, address point sources and were developed to help European farmers to use PPPs in a sustainable way. Outside of the European Union (EU), the TOPPS  BMPs can serve as a basis to develop local BMPs but local legislation, practices and knowledge need to be taken into account if local BMPs are developed.

Preventing Point Source Pollution - Farm and Equipment Design

The project identifies that most causes of point source pollution relate to

  1. filling and
  2. cleaning of spray equipment and
  3. remnant spray management

Whilst operator practices have the biggest impact, farm design and equipment design also have an effect. For example, Roettele et al found that a large proportion of  the farmers in the TOPPS study fill their sprayers on farm with “no filling place equipped to collect directly any spills of PPP concentrate.” This implies that surface water sources local to such filling points are vulnerable to point source contamination.

The study also suggests that the design of sprayers can impact on each of the above three points e.g:

  • induction hoppers can help reduce spillage when filling
  • rinse tanks of sufficient size can enable on field cleaning whilst
    rinse nozzles can facilitate more effective internal cleaning of the sprayer.
  • Improved tank design causing a reduction in the total residual
    volume of a sprayer - i.e. the quantity of PPP left in the tank and which the spraying equipment is unable to expel – would reduce the burden of remnant spray management

Roettele et al also found that unreliable measuring scales were used in 77% of cases causing spray to be either under or over diluted. Since it is important to correctly dilute PPPs to avoid crop and environmental damage, to achieve the desired level of control and to avoid left over spray, this finding indicates the need for technical improvements. Measuring devices should be used which measure the required amount of water correctly and which shut automatically when the desired water volume is in the tank.
The TOPPS project reports in full in October 2008 by which time it is intended that training frameworks and materials aimed at supporting correct operator behaviour will also become available. In the meantime many resources including the BMPs are available from and the underpinning principles are outlined here.

Roettele, M., Balsari, P., Doruchowski, G., Franssens, V., & Peterson, P. H. (In preparation). Technical Requirements to enable best management practices in order to prevent losses of plant protection products to water - lessons from TOPPS.

Footnotes 1 Roettele, Balsari et al, in preparation, liken the proportion to ‘1 cent in 100 million euros