|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|
Agriculture is a main source of pesticide pollution of the aquatic system, both groundwater and surface water. This is related to the facts that
- agricultural land covers roughly 40% of the total land area of EU-28, equivalent to 174 million ha in 2013,
- agriculture is a large user of pesticides for producing food and feed.
The applied pesticides can be transported to water bodies via leaching and surface runoff. The loss of pesticides from agriculture to groundwater and surface waters depends on farming system, management, soil type, geomorphology, and climate.
These factors define both
- the sources of pesticide pollution and
- the transport pathways (e.g., downward leaching to groundwater or overland flow (surface run-off), erosion, and subsoil lateral leaching to surface waters).
This article provides a brief overview of the sources of pesticide pollution in agriculture. A summary of farming systems and of management in EU-28 is presented, as these define the use of pesticides in agriculture.
|1. Farming systems and management in the EU|
|2. Use of pesticides in the EU|
|3. Monitoring pesticide residues in drinking water in the EU|
|4. Pesticide use in the world|
About 60% of the utilized agricultural area in the EU-28 in 2013 was classified as arable land, 34% as grassland and 6% as permanent cropland (orchards, vineyards). These areas are managed as some 10 million farms, which are mainly family farms. In practise, each farm is managed in a unique manner.
There is a huge variation in farming systems, because of differences in their resource basis, enterprise pattern, crops, animals, management and also the use of pesticides. A first characterization is commonly made between
- specialized crop production systems,
- specialized animal production systems, and
- mixed production systems.
Eurostat (2015a) distinguishes 8 main farm types (Table 2), which reflect the aforementioned three categories, and three main classes of land use.
Table 2: Agricultural holdings by farm type in EU-28 in 2013 (Eurostat, 2015a)
|Code||Farm type||Number of holdings in EU-28 (millions)||Number of holdings in EU-28 (%)|
|1||Specialist field crops||3.20||29.6|
|3||Specialist permanent crops||1.89||17.4|
|4||Specialist grazing livestock||1.86||17.1|
1) Granivorous literally means ‘feeding on grains and seeds’. In practices it means farms with monogastric animals, mainly pigs and poultry, where often a significant fraction of the feed is imported.
2) Mixed crop-livestock holding have neither livestock nor crop production as dominant activity; an activity is called dominant if it provides at least two-thirds of the production of an agricultural holding.
The type of farm and the management on the farm both influence the potential transport of pesticides to drinking water resources. Pesticides are predominantly used in specialist crop production systems, which will therefore get most attention in the further review.
Management is often considered to be the fourth production factor, next to land, labour and capital. It is considered an important factor for the pollution pressure of pesticides on drinking water resources. Management is usually defined as ‘a set of activities to achieve objectives’. It includes a sequence (cycle) of
- analysis of the current situation and of possible options,
- decision making,
- planning of the activities,
- monitoring, and
- verification and control of achievements.
These management activities relate to different components of the farm.
The management affects inputs, transport and output of pesticides. Following the division into crop farms and animal farms, a distinction is made between crop management and livestock management, where in the case of pesticides the main focus will be on the crop management, because pesticides are used most for crops and crop protection.
Crop management includes:
- crop rotation aspects, e.g. crop sequence, use of cover crops and under growth, use of legumes, use of buffer zones.
- soil cultivation aspects, e.g., conventional (mouldboard) ploughing or minimum tillage or zero tillage.
- nutrient management, e.g., use of soil fertility analyses, organic farming approaches, use of animal manures without low emission techniques, use of animal manures with low-emission techniques, use of fertilizers, use of GPS controlled fertilizer application.
- pest management, e.g., use of chemical control and/or biological control measures.
- water management (irrigation and drainage aspects), i.e., no irrigation, sprinkler irrigation, flood irrigation, drip irrigation and/or fertigation. Crop rotations are important for the sustainability of agricultural system (Mudgal et al., 2010). However, empirical data are scarce about crop rotations, because there is little or no monitoring of crop rotations in EU countries (Lorenz, Fürst, & Thiel, 2013; Schönhart, Schmid, & Schneider, 2011).
Crop rotations can vary from no rotation monoculture, (one crop only) up to six and even beyond. Typical four year crop rotations in Western Europe may consist of “winter wheat-sugar beet-winter wheat-potato”, or “winter wheat-silage maize-winter wheat-sugar beet”. A typical three year rotation may consist of “winter wheat-winter barley-sugar beet/silage maize” or “winter wheat-winter wheat-sugar beet”. A typical two year rotation may consist of “winter wheat-silage maize/sugar beet” (Leteinturier, Herman, Longueville, Quintin, & Oger, 2006).
The crop statistics from Eurostat distinguish 17 categories for cereals and 29 for other main crops, 40 categories for vegetables, 41 for permanent crops (Eurostat 2015). Within each crop large differences can exist. Cereals can be managed intensively, such as in northern France, Germany and the United Kingdom, but can also be important for nature conservation such as in parts of Spain. The pesticide usage differ greatly between these crops and cultivation intensities.
The use of pesticides within the EU is not measured on the field or at farm level. So a estimation can be made based on the sales values for each country. ‘Fungicides and Bactericides’ and ‘Herbicides, haulm destructors and moss killer’ are the two groups of pesticides that are sold most throughout the EU (Figure 2). France, Germany, Italy and Spain are the largest agricultural producers in the EU and also use the most pesticides in total volumes. These countries use 3 up to 7 kg/ha pesticides averaged for all the agricultural land. The average pesticide use in the EU was 2.9 kg/ha in 2015, with the Netherlands, Belgium and Italy the most intensive users. They applied 9.3, 7.72 and 7.0 kg/ha respectively (FAOSTAT, 2018). Figure 2 shows data for 16 EU countries, data for other countries is not publicly available.
Compared with 2011 a slight increase (1.6%) in total amount of pesticides used is seen in 2016. However, large differences between countries exist. For example, Denmark reduced the pesticide sales by 50% between 2011 and 2016. This can be related to the pesticides tax increase that was introduced in 2013 (Ørum et al., 2018) A large part of the revenue from the pesticide tax is used for pesticide research programs in Denmark (Nielsen et al., 2011).
The total pesticide sales provide a general insight for pesticides usage and potential pollution, because it does not take into account pesticide fate and specific pesticide properties. This is important to add because such factors are needed to make good long-term impact indications, also for potential pollution of drinking water sources.
Both ground and surface water resources are monitored in the EU to ensure their quality and control pollution events. Because of the large number of different pesticides the monitoring data is still scarce and a higher density of monitoring points and tested substances is recommended.
Figure 3 shows the groundwater monitoring stations for 2010 and 2011. Several EU countries are not filled because of data restrictions. However when data is available groundwater monitoring showed that 7% of the groundwater monitoring stations measured an exceedance of the allowed levels for at least one pesticide. Atrazine and its metabolite are most frequently detected at too high levels (Eurostat, 2011). Pesticide concentrations in river water do exceed the accepted level often, but it depends a lot on the type of pesticide taken into account.
It should be noted that higher concentrations are mainly measured in areas with intensive agricultural activities.
Beside groundwater also rivers are monitored for pollution. There are exceedances of the acceptable level, with as main group cyclodiene pesticides (Figure 4). Commonly used herbicides like atrazine and alachlor did not exceed the maximum level in any case. Not all pesticides monitored and detected in rivers and groundwater are still applied, for example atrazine is banned in the EU in 2004. This also indicates that there can be a time gap between pesticide usage and actual water source pollution.
This article, in line with the FAIRWAY project, focusses on the EU. However, pesticides are used worldwide. The amount and types used vary a lot between countries (Figure 5), but published global pesticide use data are sparse (Benbrook, 2016). Countries with pesticide intensive cultivation use a much higher amount per hectare than countries with more arable crop production. Beside that improved technologies (precision farming) lower the amount of used pesticides.
High usage rates are found in Latin America and East Asia, where besides the type of agriculture also the training level of farmers causes the higher average amount of pesticides applied.
As mentioned, global pesticide use data are scarce. Benbrook (2016) analyzed the trends in glyphosate use in the United States and globally. He showed that globally, the use of glyphosate has increased 15-fold since so-called ‘Roundup Ready’ genetically engineered glyphosate-tolerant crops were introduced in 1996. Benbrook (2016) concludes that no pesticide has come even remotely close to the intensive and widespread use of glyphosate in the US and likely in the world. Figure 6 shows the glyphosate use in the world between 1994 and 2014 and in the US between 1974 and 2014.
Worldwide, glyphosate use was modest in the 1970s, compared to the most heavily applied herbicides then on the market (e.g. atrazine, metolachlor) (Benbrook, 2016). Both worldwide as well as in the United States, the amount increased steadily until 1995, but when genetically engineered crops gained market share, the agricultural application of glyphosate rose rapidly; it increased 14.6-fold between 1995 and 2014 worldwide and 9.1-fold in the same period in the US. Overall, glyphosate use in the agricultural sector rose 300-fold between 1974 and 2014 in the US. The growth of use is also illustrated in Figure 7, showing the importance of use in soybean and corn cultivation in the US.
Note: For full references to papers quoted in this article see