|Main authors:||Meindert Commelin, Jantiene Baartman, Piet Groenendijk, Oene Oenema, Susanne Klages, Isobel Wright, Tommy Dalgaard, Morten Graversgaard, Jenny Rowbottom, Irina Calciu, Sonja Schimmelpfennig, Nicola Surdyk, Antonio Ferreira, Violette Geissen|
|FAIRWAYiS Editor:||Jane Brandt|
|Source document:||»Commelin, M. et al. 2018. Review of measures to decrease pesticide pollution of drinking water sources. FAIRWAY Project Deliverable 4.2, 79 pp|
The review and analysis we have undertaken show that there a large number of measures are available to reduce pollution of drinking water sources by pesticides from agriculture. In the literature the main focus is on diffuse source pollution, where it is important to reduce transport from agricultural fields to water sources. The reviewed measures can be grouped into two main approaches;
- pathways based measures and
- source based measures.
In the first group the aim is to reduce the transport, either overland or by leaching, of the applied pesticides. The source based measures focus on reducing the total input of pesticides in the system and by that reducing potential pollution.
When comparing the results of the literature review with the quantitative analysis many similarities emerge. Literature is clear about the potential effectiveness of buffer strips and drift reduction measures, although they have to be designed to match local conditions. The calculated effect ratios of these measure are both low, 0.26 and 0.28 for drift reduction and buffer strips respectively, indicating that athese are very effective measures to decrease pesticide pollution. This is also shown in literature for drift reduction (Zande et al., 2008) and buffer strips (Krutz et al., 2005; Reichenberger et al., 2007).
Tillage methods are clearly related to transport pathways of pesticides and are therefore extensively studied (Alletto et al., 2010). However, the effectiveness of tillage adjustments to reduce either overland transport or leaching of pesticides is unclear and often small. In addition, Flury (1996) indicates that for tillage methods the transport pathways are often mutually exclusive. So if overland flow is reduced, infiltration will most likely increase and, as a consequence the leaching risk for pesticides increases as well. The quantitative analysis also shows this uncertainty for tillage methods, given a very wide variation in experimental results for both groundwater and surface water pollution, with average effectiveness in both cases above 1, indicating a negative effect on pollution. However, many studies focussing on the effect of tillage on the overland pathway show a slightly positive effect on surface water pollution. So, as stressed by Alletto (2010), tillage method changes can be used to reduce pollution of mainly surface water, but never as main measure. It can be applied in combination with other measures. To understand the effectiveness of tillage method changes a more detailed quantitative analysis could provide useful insight, in this case co variates like climatic zone, soil type and vegetation type should be included.
As expected, input control measures are shown to be effective in the quantitative analysis, all reported experiments show a decrease of pesticide transport to both ground and surface water sources. However, input control measure often are less easily applied and adopted due to the effect of the reduced pesticide uses on yields and weed pressure. A good alternative approach has to be present otherwise this measure will not be profitable for farmers to apply (Gentz et al., 2010). A combined approach, with Integrated Pest Management (IPM) is regarded as an effective measure (Reichenberger et al., 2007). However, investigation on the effectiveness of IPM is scarce because of the larger (farm) scale on which this is often applied, which makes quantitative analysis of effectiveness complex.
Measures implemented in the case studies of the FAIRWAY project included the implementation of biobeds or bio filters for point source pollution and the use of policy and management changes on higher levels. The biobeds/filters did show good results in the case study evaluation and the quantitative analysis, however, further data on their effectiveness is scarce. Policy and community approaches to pesticide use and pollution through national laws or regulations which restrict or prohibit the use of pesticides are not reviewed in this report, but they can affect the amount of pesticide used to a large extent and thus affect the risk of pollution.
Note: For full references to papers quoted in this article see