In this section of FAIRWAYiS we review and assess measures to decrease pesticide pollution of drinking water resources. The work builds on insights and results gathered in EU-wide and global projects and studies. It provides an overview and assessment of the effectiveness and efficiency of measures aimed at decreasing pesticide pollution of drinking water reservoirs and complements the section »Review of measures to decrease nitrate pollution of drinking water sources.

We start by giving some background information on changes in the use of pesticides, concerns about their safety, EU directives and guidelines, factors that affect their pollution potential and measures that are used to reduce and control it.
»Background.

Pesticides are used at different rates in Europe and around the world; as a general rule more intensive agriculture will also use more pesticide per ha. In the EU the average use is around 3.0 kg/ha per year. Groundwater and rivers are monitored in the EU to control the water quality and pesticide levels are also checked. We give an overview of farming systems and management in the EU-28, use of pesticides and monitoring of residues in drinking water before taking a quick look at pesticide use in the rest of the world.
»Agriculture and pesticides use in the EU-28 and worldwide

We then look at the existing pathways and transport mechanism of pesticides to water resources. The driving factors for pesticide pollution are in firstly water facilitated transport through or over the soil. Secondly erosion of sediment can transport sorbed particles. Areal transport occurs with spray drift during application and is a threat to surface water quality.
»Processes and factors that transfer pesticides to drinking water resurces

To conduct the review of measures to decrease pesticide pollution we undertook a systematic search through online databases and via local searches by partners of the FAIRWAY project throughout Europe. The search yielded 112 experimental comparisons in both journal articles and reports of institutes and universities. In addition a survey was done among the partners and case studies to investigate existing measures and their performance. All these measures were uniformly and concisely described.
»Review methodology

The review is in two parts. Firstly there is a qualitative review of described and tested agricultural measures in scientific literature and in the case studies
»Qualitative review of measures and practices that decrease pesticide pollution.

This is followed by a quantitative analysis of the effectiveness of these measures to reduce pollution of ground and surface water.
»Quantitative analysis of measures and practices.

We finish with the main findings of this review which are:

• Measures can be categorized into either source-based or pathway-based measures. Each pathway (leaching to ground water, or overland transport to surface water) has its own specific and effective measures. Spray drift forms a separate pathway to surface water.
• The driving factors for pesticide pollution are in the first place water facilitated transport through or over the soil. Secondly also erosion of sediment can cause transport, when sorbed particles are transported. Areal transport occurs with spray drift during application, and is a threat for surface water quality.
• Buffers, drift reduction measures and IPM are effective measures to reduce pollution.
• Tillage methods are extensively studied in relation to pesticide pollution, but they do not have a clear effect and are thus not effective to be used to reduce pollution of either ground or surface water
• For all measures, the local design and pedo-climatic conditions are of major importance to be effective. A quantified relation between pedo-climatic conditions and measure design or effectiveness is still lacking and would improve the applicability of these measures.

»Discussion and conclusions

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