Umweltbundesamt
Click to enlargeMassive amounts of pesticides are used for farming, mainly in order to keep crop plants healthy and eliminate weeds and pests. But pesticides also have a negative impact on biodiversity and on the waterbody quality of nearby biotopes.
Pesticides are chemical or biological substances that are used by farmers to kill undesirable organisms. Pesticides protect crop plants and crops from various pests such as insects that feed on (a) leaves, grain and the like; (b) field weeds; and (c) pests that attack stored products. As of 2011, some 250 chemicals were being used in a total of 691 different pesticides. Around 40,000 tons of pesticides are sold in Germany annually, and in 2011 a new record was set in this domain (43,000 tons). And while pesticide sales figures do not necessarily reflect actual pesticide use (because growers often stock up on pesticides when prices are low), these figures nonetheless provide a reasonably accurate picture of the massive amounts of pesticides that are sprayed on German crops year in and year out.
Herbicides account for the lion’s share (40 per cent) of the pesticides used in Germany. As most pesticides have a wide application domain, they can also have adverse effects on benign plants and animals. Hence large scale use of pesticides in the biosphere entails not only benefits for farm production, but also entails a high level of risk for nature, groundwater and biodiversity.
Ever more intensive farming and increasing energy-crop cultivation have drastically changed the conditions under which pesticides are used in Germany. Pesticides are relevant for environmental protection in that they can contaminate nearby biotopes and groundwater via (a) drifting of pesticides or contaminated dressing agents; or (b) cropland run-off.
Intensive use of highly potent broad-spectrum herbicides and insecticides inevitably results in fauna impoverishment and in devastation of the habitats that provide the food supply for many birds, mammals and other animal species that inhabit farmland ecosystems. Numerous scientific studies have shown that pesticides entering the food chain are one of the main causes of biodiversity loss for avian species such as skylarks, yellowhammers and partridges. There is also scientific evidence that the decrease in flower pollinators is associated with the impact of pesticides on flower availability periods and flower diversity.
The deleterious effects of pesticides pose a threat not only to nearby natural habitats, but also to cropland itself. Examples of this include soil fertility loss attributable to the destruction of key soil organisms or animals that are temporary denizens of farmland, such as foraging vertebrates or flower pollinators. Other serious problems include the following: bound residues that remain in the soil for years; evidence of pesticides in groundwater or surface waters; and food contamination.
Pesticide levels in groundwater have been decreasing in recent years. Between 2006 and 2008, 4.6 per cent of the more than 13,000 near-surface groundwater measurement points exceeded the limit value for at least one pesticide substance, compared to 5.3 per cent for the previous measurement period (2001-2005). The figure for 1990 to 1995 was 9.7 per cent. However, the decrease in groundwater pesticide levels is mainly attributable to lower detected concentrations of atrazine and desethylatrazine and a number of other metabolites and chemicals whose use was banned years or even decades ago. This reflects the lag time of ecological processes that has been observed in other domains as well, and is a good reason for the application of strict pesticide approval criteria in Germany. The bad news in this regard is that traces of some currently used chemicals such as bentazone, diurone and isoproturone have been regularly detected for years in groundwater, while the good news is that today’s pesticide chemicals are detected in groundwater far less frequently than was the case with the previous generation of chemicals.
Against this backdrop, regulations concerning the environmental impact, usage methods, and reduced use of pesticides and mitigation of their negative impact on farmland aim to reduce such risks to an acceptable level. Pesticide use in Germany is governed by the following legal instruments: the Pesticide Act (PflSchG); Regulation No 1107/2009/EC; transposition into German law of Regulation No 2009/128/EC, including elaboration of the Nationaler Aktionsplan der Bundesregierung zur nachhaltigen Verwendung von Pflanzenschutzmitteln (National action plan for sustainable pesticide use). These regulations set forth objectives and measures for improved waterbody protection and biodiversity conservation. They also call for users to be provided with more advice and training, and for the regional states to strengthen pesticide use monitoring. The overarching goals of such instruments are to (a) improve compliance with environmental regulations; and (b) adopt strategies that apply to all approved pesticides, for the purpose of managing risks such as indirect effects on farmland birds and mammals that are not adequately taken into account by product approvals per se.
EU and German laws ensure that only those pesticides whose environmental impact has been assessed will be placed on the market. Whenever the UBA conducts an approval process for a pesticide, an environmental impact assessment is carried out so as to ensure that the direct impact of such products on the environment and biodiversity is minimized to the greatest extent possible. Since 1987, the UBA has conducted such assessments for well over 200 chemicals and more than 1,200 pesticides that formed the basis for the 691 pesticides that were approved in 2011. Inasmuch as these assessments are conducted separately for each pesticide, the possible cumulative effects of (a) using pesticide mixtures from tanks; or (b) seasonal spraying of a succession of pesticides are not taken into account. Hence in such settings, pesticides could exert adverse effects on biodiversity that cannot be regulated via the approval process alone. Against this backdrop, indirect ecological effects on the food chain could be lessened by imposing an across-the-board reduction in pesticide use – for example by promoting organic farming and other methods involving little or no pesticide use. Growers who opt for such methods would also need to be adequately compensated through measures such as the creation of ecological compensation areas in farming regions.
The decisive factor for assessing the environmental impact of pesticides is not so much the amount of pesticide used, but rather the potency or potency equivalence of the effect in question. When applied in low doses, today’s highly potent pesticides may be just as environmentally hazardous as previous generations of pesticides for which higher doses were used. Hence, setting quantity reduction goals for pesticides is of little avail, but does make sense for chemicals whose environmental impact can be regarded as critical but whose use cannot be banned. The cut-off criteria laid down in Regulation 1107/2009/EC aim to minimize the use of pesticides with chemical properties of particular concern. To this end, use of not readily biodegradable, bioaccumulating and environmentally toxic substances will ultimately be banned, e.g. for POPs, carcinogenic substances, endocrine disrupters and substances that are harmful owing to the changes they cause in genetic material.
Agricultural measures
The key instrument in Germany for curbing waterbody and soil pollution and biodiversity loss are (a) the future Nationaler Aktionsplan der Bundesregierung zur nachhaltigen Verwendung von Pflanzenschutzmitteln (National action plan for sustainable pesticide use); and (b) systematic monitoring by regional-state authorities of usage restrictions concerning ecosystem protection. The National Action Plan calls for across the board reduction of conventional-farming pesticide use to the actual amount needed. This can be accomplished, for example, through mandatory implementation of the principles of integrated pest control in the runup to 2014, and crop specific guidelines for integrated pest control. In addition (a) alternative farming methods involving the use of less or no pesticides should be promoted; (b) an adequate amount of ecological compensation zones in farming areas should be created; and (c) additional buffer zones should be established in fragile terrestrial and waterbody biotopes, so as to minimize damage to their native species.
Waterbody and biodiversity protection
The UBA’s motto, For our environment (“Für Mensch und Umwelt”), sums up our mission pretty well, we feel. In this video we give an insight into our work.
