Background Pesticides are one of the main sources of water pollution and aquatic environment degradation in agricultural areas. Approximately 320 000 tonnes of pesticides are sold every year in the EU, mainly to the agricultural industry. Agricultural pesticides find their way into water and sediments, threatening the sustainability of Europe’s water resources and aquatic biodiversity. The Water Framework Directive (2000/60/EC) requires aquatic environments throughout the EU to be in good condition by 2015. Another Directive on the quality of the water intended for human consumption (98/83/CE) sets the following specific pollution limits for drinking water: 0.1 µg/L for single substances and 0.5 µg/L for the sum of pesticides and their degradation products. Dealing with agricultural non-point source pollution by pesticide – and their many active ingredients - is therefore a key means of protecting the quality of Europe’s drinking water and aquatic environments. However, non-point-source pollution is very difficult to treat at the landscape scale and existing bioremediation approaches are still not optimised and do not produce the results that should be possible. Objectives The main objective of the ARTWET LIFE project was to demonstrate low-cost natural treatment systems to effectively reduce the risk of agricultural non-point-source (NPS) pesticide pollution in surface water. The project aimed to prove the value and feasibility of bioremediation treatment systems based on vegetation in artificial wetland ecosystems. It sought to test pilot-scale systems using vegetated ditches, natural and constructed wetlands, and forest plots to treat pesticides before they enter the aquatic system. The plan was to optimise each system and to maximise the mitigation capacities and potential beneficial impacts on biodiversity in the affected areas. Technical guidelines were foreseen to share the conceptual developments and demonstrated efficiency across the EU. The ultimate objective of the project was to provide a means for significantly improving the water quality to meet the requirements of European legislation, such as the Water Framework Directive, by 2015. Results The ARTWET project successfully demonstrated that artificial wetlands are a sustainable and promising option to treat non-point-source pesticide pollution. The project developed six experimental prototypes (at a laboratory scale or mesocosm scale) to test new concepts in bioremediation. Engineering solutions were proposed and the project built four demonstration prototypes at full scale in three European countries. The prototypes integrated hydraulic and biological aspects based on optimising the pesticide bioremediation processes. The project demonstrated a retention performance between 40 and 88 % even with very young systems that were still not fully vegetated. Monitoring of total concentrations of 18 pesticides has led the beneficiary to expect that more mature systems would achieve a mean mitigation efficiency of 76% (± 19%) during the agricultural season. This equates to a 73% reduction in the total load estimates. The project showed that bioremediation can totally remove some pesticides, such as glyphosate. Additionally, a recirculation of water – for example through biomassbeds – achieved an efficiency of 99.8% for pesticides mitigation even with strong concentrations of active ingredients widely used in vineyards, such as metalaxyl, penconazole and chlorpyrifos. High efficiency of mitigation was also shown for several herbicides used in corn, wheat and tomato crops. The artificial wetlands demonstrated by the project are low-cost solutions as they are based on complementing and completing natural biodegradation potential and existing preventive actions on the farm or catchment area. The solutions also reduce the cost of subsequent drinking water treatment, particular in view of meeting the requirements of Directive 98/83/EC on the quality of drinking water. Appropriate hydraulic and biological adaptations can fit the solutions to different scales and (pollution) contexts, including a farm, plot, catchment area or entire landscape. They can also address other challenges, including urban runoff water treatment, other non-point-source pollution such as nitrate or phosphorus pollution, erosion control and downstream biodiversity protection. To facilitate transfer across the EU, the project published a technical guide with advice of choosing, adapting and building the appropriate system. It also conducted a series of dissemination actions at local and European levels, including a non-technical guide and scientific presentations. One year after the end of the project, three new systems had already been implemented elsewhere: two in France and one in Germany. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).