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Report of the sub-committee on the environment and health.

11. The sub-committee’s summary with conclusions and recommendations

11.1  Introduction and mandate

On 15 May 1997 the Folketing (the Danish Parliament) unanimously passed a parliamentary resolution urging the government to appoint a committee with independent expertise to analyse all the consequences of totally or partially phasing out the use of pesticides in agriculture and to examine alternative methods of preventing and controlling plant diseases, pests and weeds.

The mandate for the Sub-committee for Environment and Health stated that the sub-committee was to assess the environmental consequences of a total or partial phase-out of pesticides, including the effects on groundwater as a resource for the population and the natural environment, surface water as a resource for flora and fauna, and the terrestrial ecosystems in agriculture and forestry as a resource for flora and fauna.

In its assessment of the health consequences, the sub-committee was to include the effects of pesticides on the people using them and the effects of using the proposed cultivation systems. On the other hand, the sub-committee was not required to consider the health and environmental aspects of the industrial production of pesticides.

In its work, the sub-committee has analysed the following scenarios in relation to present production practice, which is characterised by a treatment frequency index of 2.51:

A total phase-out of pesticides (the 0-scenario). This scenario is described as a reference situation, and the environmental and health consequences of a total phase-out are compared with the present situation. Here, the treatment frequency index is 0.

Use of pesticides only for pests covered by the quarantine laws (the 0+scenario). In this scenario, pesticides would be used to comply with specific requirements concerning purity or for controlling pests defined in orders from the Plant Department. Here, the treatment frequency index is 0,05.

Use of pesticides in crops with serious losses (the +scenario). In this scenario, pesticides would only be used for limited areas in which large yield losses could be expected or where production of specific crops could not be maintained. The scenario also covers the 0+scenario’s areas. Here, the treatment frequency index is 0,50.

Reduction of pesticide consumption to a level without yield losses (the ++scenario). In this scenario, use would be made of all available technical and cultivation methods that reduce the use of pesticides without significant economic losses. The scenario covers the areas of the 0+scenario and the +scenario and is based in part on the principle of integrated prevention and control. Here, the treatment frequency index is 1.73.

The sub-committee has included a number of consequential analyses covering soil fauna, wild flora, ponds and the daily intake of pesticide residues in food products. The sub-committee has reviewed the latest knowledge on the occurrence of pesticides in groundwater, watercourses, lakes, ponds, soil water, drain water and rainwater and has assessed the dispersal and fate of the pesticides through surface run-off, spray drift and evaporation, degradation and leaching. The pollution from filling and washing sites for spraying equipment has also been assessed. The sub-committee has assessed the effects of pesticides on flora and fauna in cultivated and uncultivated terrestrial ecosystems – watercourses, lakes and coastal waters – and the exposure of and effects on humans – both agricultural workers and the population as a whole.

The sub-committee has looked in particular at the coformulants used in connection with the pesticides and has also assessed the pesticides in relation to other chemical substances used in agriculture, including natural substances and pesticides of natural origin. In addition, the sub-committee has examined various methods for ranking pesticides and investigated the possibility of operationalising the precautionary principle in connection with pesticides.

Lastly, the sub-committee has assessed the environmental and health aspects of a number of alternative and new methods in relation to the scenarios set up for total or partial phasing-out of pesticides.

The general conclusion of the sub-committee concerning the scenarios is that only the 0-scenario and the 0+scenario are based on consistent use of the precautionary principle. The +scenario, in which the use of pesticides is reduced by 80% compared with present production would result in a marked reduction of the dispersal of pesticides and the exposure to them but would still imply a potential risk of effects where pesticides are used. In the ++scenario with a treatment frequency index of 1.73, the reduction in the use of pesticides would be smaller than the treatment frequency targets in the Pesticide Action Plan from 1986. This plan did not take account of the special problems with groundwater and surface water.

11.2 Occurrence of pesticides in the environment

The sub-committee has reviewed the latest knowledge concerning the occurrence of pesticides in groundwater, watercourses, surface water, drain water, soil water and rainwater, and has assessed the dispersal of pesticides through surface run-off, spray drift and evaporation. It has also assessed the degradation and leaching of pesticides and the pollution from filling and washing sites. The sub-committee has drawn specific conclusions in the individual areas and has arrived at the following general conclusions and recommendations:

Conclusion concerning lack of time series

1. There are studies of pesticides in the different compartments: groundwater, watercourses, drain water, soil water and rainwater. There are only a few measurements of pesticides in ponds and lakes. Only for the groundwater are there time series, but the measuring programmes have not been going on long enough to allow the trends to be discerned. The monitoring programme in connection with Aquatic Environment Plan II will in future supply data for such time series.

Conclusion concerning pesticides in groundwater

2. In the expanded analytical programmes in the national groundwater monitoring programme, pesticides or degradation products have been detected in 34% of the analysed screens in the interval 0-10 metres below ground level. The limit value was exceeded in 23% of these screens. The detection frequency decreases with the depth, which may indicate that pesticide residues from the last 50 years’ consumption, which has been rising throughout that period, are moving towards the deeper aquifers, with increasing future groundwater pollution as a consequence. Another explanation might be that degradation occurs during the downward movement because the concentrations in the deeper soil strata have been exposed to biological and chemical degradation for a longer period than the concentrations found in the uppermost soil strata. Only when sufficiently long time series from the monitoring programmes become available – in 5 to 10 years time – will it be possible to assess these hypotheses. The latest research indicates that some pesticides in aquifers degrade very slowly, while others show degradation.

Conclusion concerning size of the finds

3. In the expanded analyses in the groundwater monitoring programme, pesticides or degradation products were found in 21% of the screens examined. The limit value was exceeded in 13% of these screens. The degradation product BAM from the now banned herbicide dichlobenil has been detected in about 30% of the wells covered by the water companies’ raw-water monitoring system. However, many other substances used to treat crops have also been detected in relatively many of the wells included in the monitoring system. The finds of pesticides in drain water and soil water are higher than the finds in groundwater and reflect the concentrations that can later move towards the groundwater, during which they can undergo degradation and possible formation of metabolites. In both watercourses and ponds, a number of pesticides have been detected in higher concentrations than the effect levels measured in laboratory tests with aquatic organisms.

Conclusion concerning market gardens and berry and fruit production units as point sources

4. With the high treatment frequency index used in nurseries, market gardens and berry and fruit production units, there is a potential risk of pollution of the surroundings, including the groundwater.

Conclusion concerning lack of data for describing the dispersal and transformation of pesticides in the environment

5. The sub-committee has noted that, in connection with the pesticides detected in the different compartments, only a fraction of the quantities of pesticide used can be accounted for, neglecting degradation. There is thus a lack of data on the total mass flows and the largest flows, including evaporation and spray drift, and a lack of concrete, systematic measurements of the degradation and metabolism as elements of the main mass flow analysis. It is thus not possible to arrive at a real and complete description of the fate of the pesticides in relation to the environmental and health loads.

Conclusion concerning future pollution of groundwater

6. The finds of authorised pesticides above the limit value in both groundwater near the surface and deeper aquifers indicate that the present authorisation scheme does not ensure completely against future pollution of the groundwater. A warning system for pesticides has therefore been established to enable rapid assessment and possible removal of authorised pesticides.

Conclusion concerning spray drift and evaporation

7. Two reasons why pesticides are found in precipitation, surface water and unsprayed areas are spray drift and evaporation. Calculations indicate that there can be considerable evaporation of the substances fenpropimorph, pendimethalin, prosulfocarb and trifluralin. There is thus a risk of these substances being dispersed in the atmosphere and detected in rainwater and surface water. The fate and occurrence of these substances in the atmosphere over Denmark have not been investigated.

The sub-committee's recommendations

In Denmark and the EU, authorisation of pesticides is at present based on analyses of research results and assessment of the consequences for health and the environment. Particularly the fate of the pesticides is thus not subjected to an analysis of the uncertainties and actual variations used in an integrated mass flow analysis because, for such an analysis, data are needed on the actual use, dispersal and degradation under Danish conditions. The sub-committee recommends that an actual mass flow analysis be carried out in connection with the review of pesticides with a view to renewal of their authorisation in pursuance of section 33(4) of the Act on Chemical Substances and Products. The analysis must include both average and "worst-case" situations based on measurements and experience gained in the period the substance in question has been in use. If data are lacking on the individual flows in this mass flow analysis, the sub-committee recommends that the precautionary principle be applied in the assessment of the substances in order to counteract or prevent any consequences of the dispersal of the pesticides for human health and the environment.

The sub-committee recommends that the gross list set up with a view to reassessment of pesticide leaching be included in recommendations on substitution with less dangerous substances in the use situation. The sub-committee also recommends that new products be assessed in relation to the gross list and in relation to alternative, non-chemical methods. Substances that are thereby placed at the critical end of the gross list or that can be replaced by suitable alternative, non-chemical methods should not be authorised. The sub-committee recommends use of the following alternative methods:

	mechanical weed control
	biological control of pests
	use of resistant varieties, including genetically modified crops
	preventive operating methods.

Since the alternative methods can also be harmful to the environment and health, their suitability should be assessed in the same way as chemical methods.

The sub-committee recommends that pesticides no longer be used in areas where groundwater is extracted for drinking purposes. In these areas, consideration can be given to nature rehabilitation with respect to flora and fauna, as proposed in the recommendations in section 11.3.

The sub-committee also recommends that evaporation and atmospheric, chemical conversion of pesticides be taken into account in the authorisation of pesticides.

The sub-committee recommends that further clarification be sought of the effect of the dispersal of pesticides from disused and existing nurseries, market gardens and berry and fruit plantations and buried waste on the present groundwater pollution and the surroundings in general. Lastly, the sub-committee recommends that improved rules be drawn up for when washing and filling of spraying equipment may take place.

11.3 Impacts of pesticides in the environment

The main impacts occur in connection with the application of the pesticides, when organisms are directly hit, and where indirect effects occur as a consequence of the effect on food chains. Here, plants play a key role as the first link in the food chain. A Danish study has shown that the number of plant species and their frequency in the fields studied have halved in the last 20-25 years. From a farming point of view, this has been a desirable development, but it has had adverse consequences for the nature content. The main reason for the decline is the use of herbicides and changed cultivation practice. In both cultivated areas and the adjacent biotopes, the use of pesticides involves a risk of reductions in populations of plants and animals, changed biodiversity, changes in the cultivation medium and natural pest regulation, together with food-chain and indirect impacts. Generally speaking, it is not the individual field and its possible loss of wild flora that are the problem but, rather, the combined, countrywide impact on the characteristic farmland flora.

In a dialogue with the Sub-committee on Production, Economics and Employment, the Sub-committee on Environment and Health has estimated that a general reduction of the use of pesticides on an unchanged acreage would have a less beneficial effect on flora and fauna than if the same reduction were achieved by establishing permanent spray-free edge zones and banning spraying in environmentally sensitive areas.

The lower fauna are affected both directly by treatment with insecticides and indirectly through the removal of plants and microorganisms as food resources through the use of herbicides and fungicides. The effect of the different types of pesticide is partially specific and proportional to the treatment frequency index for fungicides, herbicides and insecticides. Therefore, in comparisons of the scenarios, the treatment frequency index is an indicator of the undesirable side effects of the use of pesticides on individuals, species and communities of plants and animals (see section 5.1 and chapter 10). If treatment with herbicides were omitted, the insect fauna could be expected to increase by a factor of 2-7, measured as individuals, and by a factor of 1.5, measured as the number of species per sample. If treatment with fungicides were omitted, the fungivorous insect fauna would increase for a time by a factor of 1-2.5. If treatment with insecticides were omitted, the insect fauna would increase by a factor of 2-4. The effect of fungicides and insecticides is often shorter than the effect of herbicides because the elimination of weed affects the fauna all through the season.

The sub-committee has assessed the scenario analyses for springtails and earthworms, since these are the only groups of soil organisms for which sufficient data are available (see chapter 10). It can be concluded that the population density of neither springtails nor earthworms is affected by the pesticides authorised in Denmark, and used in the scenario for present production, but that it is affected by crop rotation, soil treatment, fertilisation and any second crops. Scenarios that include increased use of manure and clover grass would benefit these groups of organisms.

The sub-committee concludes from the scenario analyses carried out (see chapter 10) that the populations of partridge, whitethroat and yellowhammer would increase in all scenarios in relation to present production and that all the scenarios show a significantly increased population density for these species. This applies to the 0-scenario, the +scenario and the ++scenario. For the other species, the index would be unaffected by the use of pesticides, compared with present production. Since the direct toxic effects on birds today are insignificant (see section 5.1), it is the indirect impacts that would be important, e.g. changes in the birds’ food resources. In this connection, it makes no difference to the birds whether their food resources are removed by means of pesticides or by mechanical or other methods. Inter-row cultivation and harrowing could constitute a risk to ground-nesting species. Similarly, early and/or more extensive soil preparation in the autumn would very probably have considerable, adverse effects on the birds because stubble fields are a very important foraging area for many species in the autumn months.

For all the species except partridge and, to some extent, whitethroat, the analyses show a significantly larger number in the organic scenario than in the 0-scenario because of the difference in crop rotation. However, the crop rotations used are based on organic farms as they were in the 1980s, when the forms of operation and land use differed from present-day organic farming.

From the results of analyses with two different models, the sub-committee concludes that there could be an improvement in the conditions for wild plants and those animal species that depend on them as a food resource in all the scenarios without the number of wild plants growing out of control provided mechanical weed control and limited chemical control were used. In the +scenario, a number of wild plant species could occur with greater frequency in crop rotations with either beets or rape. A more varied plant community could therefore be expected, providing food resources for a more diversified animal community (invertebrates and their predators). However, in view of the poor competitiveness of beets, this crop rotation would hardly be profitable unless new, alternative methods were found for controlling weed in beet crops. For the crop rotation with rape, the analyses show that there would be a marked fall in the number of seeds in the seed pool after 25 years, compared with the situation in present production after 25 years because mechanical weed control with spraying against couch grass every ten years is more effective than conventional spraying. However, these analyses must be treated with caution because the model has not been verified in practice.

From the model analyses carried out, the sub-committee concludes that there would probably be effects on both flora and fauna as a consequence of run-off in scenarios corresponding to present production, the ++scenario and the +scenario. The probability of effect falls with the quantity of pesticides used in the scenarios. The models show that, all else being equal, the use of pesticides in the crops winter cereal, potatoes, beets and peas constitutes a serious risk to the flora and fauna in ponds. Less burdensome crops are spring cereal, spring rape, maize and, to some extent, winter rape. The model predicts that the critical pesticides for algae and aquatic plants (macrophytes) in ponds are isoproturon, glyphosate, fenpropimorph, ethofumesate, metamitron, pendimethalin, metribuzin, prosulfocarb, mancozeb, maneb and clopyralid. Crustaceans and insects are largely equally sensitive, and the simulated effects on crustaceans can in principle be considered to apply to insects as well. The critical pesticides with respect to effects on crustaceans and insects are esfenvalerate, propiconazol, pendimethalin, metribuzin, prosulfocarb, mancozeb and maneb. If there are no run-off events within a growth season, the only source of load on the pond is spray drift. The analyses show that this supply is only of importance in the case of esfenvalerate, with a 6-9% reduction in daphnia biomass.

Conclusions concerning spray drift and impacts on the terrestrial environment

During spraying, spray drift carries pesticides to the surrounding areas. However, hedgerows, dikes, dry stone walls and other small biotopes are so narrow that they should in practice be included in the area that is affected by spray agents. Spray drift can affect both terrestrial and aquatic ecosystems. Several studies have demonstrated effects from spray-agent drift up to 50 metres from the sprayed area. However, most of the flora were only affected in an area between 0 and 5 m from the field. However, there is a lack of experimental data on effects of herbicides in low doses on wild plant species, and the extent of spray drift and its effect on wild flora have not been systematically studied in Denmark. In both the 0-scenario and the 0+ and +scenarios, the consumption of herbicides would be reduced and thus the risk of spray drift to areas near the sprayed field. This would considerably reduce the load, whether spraying was discontinued altogether or was only carried out occasionally. However, owing to the lack of data, it is not possible to quantify the beneficial effect on the vegetation. The areas affected would be reduced in step with the herbicide consumption. In the 0+scenario, the load would be reduced to the few localities in which pesticides were used. In the 0-scenario, there would no longer be any impact on the neighbouring areas.

For the aquatic environment, any form of impact from pesticides, including changes in the flora and fauna in coastal waters, lakes, ponds and watercourses, is undesirable. Of the aquatic ecosystems it is particularly ponds, watercourses and lakes near fields that could potentially be affected. It is likely that the freshwater environment is already affected by the present use of pesticides, but it is not possible on the basis of the existing data to quantify the impact at national level. On the basis of information from county authorities it is provisionally estimated that around 2% of the unfulfilled targets on approx. 11,000 km of watercourses are due to toxic substances, including pesticides. The available concentration levels indicate, in particular, that it is insecticides and, among these, particularly the pyrethroids, that have an adverse impact. Because of their persistence, the pyrethroids could occur in the freshwater ecosystems for a long period of time. Cases of effects of herbicides on algae and other primary producers have also been documented. However, several measurements indicate that pyrethroids and some thiophosphate insecticides are found in concentrations close to the level that causes effects according to the literature. For some pesticides this level is lower than the limit value for drinking water of 0.1 microgramme per litre.

Quantitatively, little use is made of pesticides in forestry, but in Christmas tree and ornamental greenery cultures, consumption is the same as in farming. The treatment frequency index in nurseries and market gardens is also high. There is a lack of specific studies of the effect of herbicides on forest-floor flora, but there is no doubt that even the present limited use of pesticides in forestry has a serious, adverse effect on the real forest-floor flora. Many species of such flora have a very slow rate of remigration – less than 1 metre per year –, which makes them very sensitive to herbicides, even when these are only used in connection with felling and afforestation. If herbicides were no longer used in forests it would in time be possible to recreate a forest-floor flora that was naturally adapted to the local soil and climatic conditions. However, mechanical control of undesirable vegetation in the form of deep ploughing over large areas could have the same direct effects on the flora as herbicides and thus also the same indirect effects on the associated fauna. Besides these, there would be adverse effects on soil fauna, fungal flora, the soil profile and historical monuments. Where natural rejuvenation is not used, it is important for the forest-floor flora that areas are left untreated and that rejuvenation is in the form of shelterwood regeneration with preservation of the choice of tree species. The use of herbicides in Christmas tree and ornamental greenery cultures in the +scenario and the ++scenario would result in continued low biodiversity of the flora in the areas in question unless alternative, environment-friendly methods were found.

For the scenarios in which pesticides are used there is a lack of systematic studies of how pesticides in large, continuous areas affect wild flora and the associated fauna in hedgerows, ditches and other small biotopes and in neighbouring nature areas. The effect on the flora in Denmark as a consequence of the precipitation’s content of herbicides transported over long distances is not known. Foreign studies show that effects are likely, but studies of both the effects and the atmospheric transport are needed to determine them. There is also a need to assess the effect of pesticides on aquatic organisms in relation to the actual finds in watercourses and surface water. The data and time series needed could be procured by means of a targeted monitoring programme for the affected biotopes, combined with experimental studies of the relationship between concentrations of pesticides and the level at which effects can be detected.

In the case of the use of pesticides in forestry, for the fauna it is the indirect effects that are most damaging. The long-term effects on both flora and fauna cannot be assessed owing to a lack of tools and knowledge.

For the intermediate scenarios in which pesticides are used, the sub-committee recommends more consistent and systematic use of permanent spray-free zones and protection borders to help protect watercourses, lakes and ponds and preserve the vegetation in small biotopes and nature areas, where these still exist. In this connection it must be ensured that continuous dispersal corridors are established. Where the vegetation of small terrestrial biotopes has been seriously affected by both herbicides and fertilisers in the last few decades, recolonisation will normally be very slow. Here, it will be necessary to establish permanent spray-free and fertiliser-free edge zones where it is found desirable to get the vegetation and associated fauna re-established. In addition, the sub-committee recommends actual nature rehabilitation, including recreation of a more diverse flora and fauna (e.g. introduction of amphibians and invertebrates with a low capacity for recolonisation).

The sub-committee also thinks that consideration should be given to increasing the distance requirements to watercourses and lakes.

11.4 The sub-committee’s conclusions and recommendations concerning health and safety

The risk of acute effects from pesticides is deemed to be considerably lower today than it was just 10 years ago because the most harmful products may no longer be used. Some risk cannot be excluded for persons who do not observe the rules on personal protection and correct use of pesticides and persons who use inappropriate work routines and do not practise good work hygiene. The sub-committee notes, however, that there can be considerable exposure of sprayer operators and workers in greenhouses and in the production of fruit and vegetables, where frequent use is made of pesticides.

The sub-committee concludes that the risk of occupational injuries may rise in connection with mechanical weed control through the introduction of more machines and thus more repair work and maintenance. In addition, increased manual weeding could result in a higher frequency of injuries in connection with monotonous, repetitive work (MRW). There is a generally higher risk of physical damage, particularly in the form of rheumatism, in agricultural workers. This risk is associated with stable work, milking, tractor operation and heavy physical work and is thus not related to the use of pesticides.

Neither conventional nor organic farmers are accustomed to thinking very much about health and safety, and injuries are not always reported despite the fact that the agricultural sector has many serious accidents and more fatal accidents than all other sectors of industry. The sub-committee recommends that higher priority be given to health and safety in the agricultural sector, in connection with both conventional and pesticide-free operation.

The sub-committee wishes to draw attention to the fact that knowledge is lacking concerning the ability of pesticides and their coformulants to produce allergies and their effect on the immune system. The sub-committee therefore recommends that more knowledge be built up in this area.

In view of the intensive use of pesticides in nurseries and in the production of fruit, vegetables and berries, the sub-committee recommends intensified action to reduce the exposure to pesticides in these areas.

11.5 The sub-committee’s conclusions and recommendations concerning public health

Conclusions concerning the population’s intake of pesticides

The sub-committee’s examination of the pesticide intake from food products and drinking water shows that the main source of the load on the population is the intake from berries, fruit and vegetables and, to some extent, cereals and cereal products, whereas the intake from drinking water, animal food products and fish is negligible.

In treated crops it is generally assumed that there is some residual content, so that lack of detection is usually taken to mean that the content, if any, is below the analytical detection limit.

The total average load from food products is estimated to be approx. 200 microgrammes of pesticide per day, more than half of which comes from some few types of food products – namely, citrus fruit, potatoes and apples. Around 60% comes from imported products and 40% from Danish products. There are big variations in the calculated numerical values, and, in practice, the total intake is estimated to lie between very low and about 600 microgrammes per day. However, since most of the residual content in citrus fruit is in the peel, which is not eaten, the actual daily intake of pesticides is less than 200 microgrammes per day. In this estimate, the intake via Danish products accounts for more than 50% of the total intake.

The average load at single-substance level from food products is typically around 1% or less of the current Acceptable Daily Intake (the ADI value).

Conclusions concerning epidemiological studies

The sub-committee concludes that epidemiological studies do not provide evidence that pesticides are harmful in the quantities to which the general public is exposed through, for example, diet. Similarly, one can never completely prove scientifically that a pesticide cannot result in a risk to health, but one can show, with greater or lesser certainty, the probability of a risk to health or of no risk to health. This applies to all scientific work, including tests on animals. In addition, every statement about safety in connection with the use of chemical substances is based on present knowledge, so there will always be a possibility of unforeseeable effects being found at a later date.

Epidemiological studies on effects of metabolites and non-active ingredients, which often constitute a substantial part of the products, are largely non-existent.

In the case of degradation products of pesticides in the environment, little is known in some cases about their effects on health. This applies particularly where different metabolites are formed in the environment than in test animals and humans.

More extensive use of biomarkers for exposure to and effect of pesticides would make it easier to demonstrate epidemiologically a correlation between exposure and any effects.

Conclusion concerning mycotoxins

Mycotoxins are a general problem in both conventional and organic farming because they can develop in moist conditions. They can also develop if grain dries too slowly. The sub-committee finds that mycotoxins in grain attacked by fungi are a greater risk to public health than pesticide residues in cereals and therefore recommends better control of the water content of grain, improved drying procedures and similar control measures at source. The sub-committee also recommends tightening control of the content of mycotoxins in food products.