|
Mapping, emissions and environmental and health assessment of chemical substances in artificial turf 4 Mapping4.1 MethodManufacturers and suppliers of rubber granules and artificial turf fields have been contacted to identify the market for third-generation artificial turf pitches and the expectations for new pitches in the coming years. The knowledge gathering has included information about the actual structure of artificial turf pitches and the materials used for establishing the pitches. At the request of the Danish Environmental Protection Agency, information has been gathered about any use of chemicals in connection with winter salting of the pitches and any use of herbicides as part of pitch maintenance. The mapping of conditions specific for Denmark has been based on interviews conducted via questionnaires (see Appendix 1). The mapping has also included a review and summary of publicly available reports or lectures on environmental studies. The results summary of this literature study is reviewed in chapter 3. The mapping in relation to Danish conditions has furthermore been based on inquiries made to and interviews with Dansk Boldspil-Union (DBU), football clubs and municipalities with a view to obtaining an overview of artificial turf pitches already laid and expectations for new turf pitches being laid in the coming years. 4.2 InterviewAs mentioned above, a questionnaire has been used (Appendix 1). The questionnaire has been forwarded to a couple of large players within manufacture, supply and establishment of artificial turf pitches in Denmark in June 2007. Subsequently, the questionnaire has been used as a basis for telephone interviews, among other things for registering information acquired in connection with questions about local conditions for artificial turf pitches such as maintenance, salting etc. A total of 14 municipalities, football clubs and sports associations have been asked questions and suppliers of artificial turf pitches approved by DBU and suppliers of elastic infill materials have been contacted. The information acquired in connection with the mapping, including the literature study of international experiences, form the basis of the conclusions drawn with respect to:
4.2.1 Artificial turf pitches in Denmark4.2.1.1 Number of artificial turf pitches and forecast for new pitchesAccording to information obtained from a seminar held at the Faculty of Life Sciences, Forest & Landscape, University of Copenhagen, on 28 March 2007, 45 full-scale third-generation artificial turf pitches are currently established in Denmark. This corresponds with information obtained from suppliers of artificial turf pitches approved by DBU on the basis of a FIFA certificate. This also corresponds with DBU’s website (visited on 15 August 2007) which lists 45 third-generation pitches. However, the indoor pitch in Ikast mentioned in the introduction is not included in DBU’s list. The reason for this could be that it is not a third-generation artificial turf pitch according to DBU’s definition as the infill is polyethylene-coated (PE) sand. PE is not an elastic material in itself, but it is flexible even at minus degrees due to the extremely low glass transition temperature (÷120°C). It has been stated that 25 new artificial turf pitches have been put out for tender this year (2007), which means that the municipal mergers in Denmark apparently have not temporarily postponed the propensity to invest in the area due to a restructuring of tasks in a transition period which had been expected in some supplier circles. In addition, several suppliers of artificial turf pitches have stated that more pitches, approx. ten, are already being established. 4.2.1.2 Pitch maintenance experiences (salting etc.)In relation to the maintenance of artificial turf pitches, experience is are limited as most third-generation pitches have been established in recent years (2002 and later). All football clubs and municipalities contacted, except from one respondent, have stated that they winter salt the pitches as required. The volume of salt used has not been stated for most of the pitches. If stated, the volume is between one to 16 tonnes per season. The figure of 16 tonnes was stated by a municipality in the Greater Copenhagen Area which has found it difficult to use snow removal machines. The figure is from the winter 2005/2006, which saw periods with a lot of snow. Both dry salting and salt solutions have been used. One respondent states that 150 kg of dry salt is used per application. Another states 200-400 kg salt is used per application in conditions with light frost and little snow. Both sodium chloride and potassium chloride are used in connection with the salting. One of the respondents states that magnesium chloride is used under conditions with severe frost and a lot of snow. None of the respondents stated that they use urea for defrosting pitches, but one artificial turf supplier recommends urea. One municipality provided detailed information about salting. During the 2004/2005 season, a total of 136 tonnes of road salt was used for two pitches (second-generation pitches), during the 2005–2006 season, 150 tonnes of salt was used for the pitches, while only 16 tonnes of road salt was used during the 2007 season which saw very little snow. The reduced consumption is, among other things, a result of an upgrade to third-generation pitches with rubber infill. Rubber maintains its elasticity even at frost temperatures and the salting requirement is thus expected to be heavily reduced. In snowy conditions, salting is still expected. The municipality has based its calculation on six snowy days a year. As two tonnes of salt per application is expected, the estimated consumption will be six tonnes for three pitches, i.e. a total of 36 tonnes per season. However, one of the large suppliers of artificial turf pitches states that several pitches are not salted, but only cleared of snow using snow removal machines. With respect to any use of herbicides or biocides, only one of the clubs contacted states that they have used Round Up once. All other clubs contacted stated that they had not used herbicides. Most of the pitches are still so new that they have yet to be filled with new infill material. One respondent (a high school for physical education) states that eight tonnes of a new infill is expected to be used over a period of five years. 4.2.1.3 DBU’s guides on establishing and maintaining artificial turf pitchesDBU’s website contains a guide on and a description of how to establish artificial turf football pitches (DBU, 2005) as well as a leaflet with good advice on maintaining third-generation artificial football pitches (DBU, 2004). A distinction is made between DBU, category 1 certificate pitches and DBU, category 2 certificate pitches. The category 2 pitches are only filled with silica sand while category 1 comprises FIFA STAR** and FIFA STAR* pitches with rubber granule and silica sand fillings. DBU, category 1 also covers pitches with a UEFA certificate established before 31 December 2005. In the DBU, category 1, the sublayer must be in the form of a laid-out rubber pad or a polyurethane-bound ET base course. In connection with the rubber pad, an additional bitumen-bound single-layer cast drainage asphalt base course can be used. For artificial turf surfaces with leaves >/= 60 mm, a sublayer can be deselected. However, for FIFA STAR** for stadiums, there is a requirement for underlying padding. For FIFA STAR**, artificial turf straight leaves of 50-70 mm in length must be used, and FIFA STAR* requires the leaves to be >/= 40 mm. Mono or split-fibres can be used for both types. In connection with the selection of a surfacing system, the following must be considered:
Alternative surfacing options are available (selection and thickness of material), but the owner will ultimately make the final decision in this matter. If a polyurethane casting is used, the contractor must document compliance with statutory requirements in connection with the handling of the polyurethane and that the required permits have been given. The maintenance guide offers a number of practical tips on pitch maintenance. An important element is compliance with the guide prepared by the supplier. The tips include regular maintenance in the form of cleaning, marking, deep-cleaning, surface loosening, filling up and watering. Watering can be relevant during the summer months with respect to cooling down and reduced friction. There is also a guide on winter maintenance, including salting. Salting must be approved by both the turf supplier and the rubber granule supplier. It is stated that the use of salt solution (e.g. in a mixing ratio of 1:6) seems more effective that spreading dry salt. Presalting should only be performed if frost is expected or during a change from frost to thaw. It is recommended that sodium chloride be used for the salting, but according to the guide, potassium chloride can also be used. There is a comment that large salt volumes in the long term can impede water permeability in the gravel bed. DBU[3] estimate on the annual consumption of materials in connection with maintenance:
According to DBU, there should be a minimum warranty period of five (5) years and the pitch depreciation is estimated at ten (10) years. This only applies to the pitch surface, the artificial turf and the removal of old artificial turf. The pitch supplier must be able to document compliance with the materials quality and local environment and fire regulations. The third-generation artificial turf pitches differ from the second-generation pitches in having leaves that are significantly longer (approx. 50-70 mm compared to 30 mm previously), in having infill which consists of a layer of silica sand at the bottom of the sward and a rubber granule layer at the top (or a mixture of the rubber granule and sand) and having approx. 20 mm of the artificial turf not being filled. It is stated that the new pitches abroad are laid directly on a flattened gravel layer (frost-proof) without a bound base course, but some pitches are laid with a shock-absorbing pad between the gravel and the artificial turf. All second-generation pitches in Denmark have so far been laid on a bound base course. DBU has prepared an estimate of the establishment costs for second- and third-generation artificial turf pitches. The estimated establishment costs are DKK 4.9 million and DKK 5.5-6 million, respectively. 4.2.1.4 Other comments on artificial turf pitchesA few respondents state that odour problems may occur in hot weather (rubber smell). The smell of rubber originates from a number of volatile sulphur compounds, lower organic acids (butyric acid and valeric acid) and terpenes, among others. Generally, the municipalities and football clubs surveyed indicate a high degree of satisfaction among users as regards the playing properties of the artificial turf pitches. However, one respondent states that professional football players prefer natural turf pitches. The Danish football players’ association website www.spillerforeningen.dk (in Danish only) hosts an ongoing debate on artificial turf pitches. The association conducted a questionnaire survey on this topic. Players prefer playing on natural turf, but they recognise the advantage of being able to also train in winter on artificial turf pitches. There is a debate as to whether tournament matches can be played on artificial turf as well as natural turf. The survey indicates that many people are interested in the environmental debate in connection with artificial turf. 4.2.2 Monitoring parametersBased on the knowledge gathered (see chapter 3) about the materials used in artificial turf pitches in the form of the artificial turf mat, elastic infill and possibly an elastic sublayer in the form of a pad, the following substances, based on the available material knowledge about the chemical substances which are part of the recipes or which are present as degradation products, could be relevant to monitor:
Zinc, copper, lead, cadmium, tin, mercury, nickel and chromium
Amines (dimethylamine, diethylamine, dicyclohexylamine), nitrosamines, hydrocarbons, degradation products from accelerators (carbon disulfide), styrene
Antiozonants in the form of p-phenylene diamines (primarily 6 PPD) and possibly degradation products (for SBR rubber types) Mercaptobenzothiazole (degradation product from the accelerator CBS) PAHs Alkylphenols Phthalates
For instance TVOC (total volatile organic carbon), DOC (dissolved organic carbon), EOX (extractable organic halogenes), total nitrogen, smell, impact on organisms (daphnia, algae etc.) The parameters which are relevant to monitor depend on the infill used for the pitches (rubber type, TPE, any PU coating, dyeing, natural fibres), the substances constituting the actual mat in the form of leaves, mesh, adhesive and joinings, and whether a pad is used (foamed PE, rubber granulate with PUR adhesive). For TPE and natural fibres, a number of the substances mentioned above are not relevant to monitor, as no vulcanisation is applied to these infill types. On the other hand, degradation of the natural fibre material may occur over time as a result of microbial activity. The parameters to be monitored depend on whether the health impacts are to be assessed or whether the assessment relates to the environmental impact through seeping as a result of rain and salting. Therefore, the scenarios have been divided into two main groups. The health scenarios cover the uptake of chemical substances through inhalation, via skin exposure or through oral intake. In case of inhalation, the volatile substances must be monitored, whereas uptake via skin and oral intake also include heavy substances or non-volatile substances. As regards monitoring in relation to environmental impacts, it is especially relevant to measure for the leaching of heavy substances or heavy metals in the scenarios. As many outdoor pitches are salted during periods of snow and frost, this is an important parameter to take into account in the leaching tests. In this connection, the impact of this salting on the leaching of undesirable substances into the soil and water could be of particular interest, not only in Denmark, but also in countries with climatic conditions resembling those in Denmark. There have been discussions on the relevance of leaching tests with water saturated with carbon dioxide, which is included in some of the leaching tests listed in the German preliminary standard DIN V 18035-7, because acid pH is claimed to be unrealistic as rainwater has no buffer capacity worth mentioning. It may therefore be interesting to observe leaching from the materials constituting artificial turf pitches in the presence of calcium chloride, which is mentioned as one of the substances that can be used for salting according to DBU. Calcium chloride results in an acid reaction in solutions, contrary to sodium chloride and potassium chloride, and may thus increase the leaching of heavy metals, primarily zinc. 4.2.3 Various standardsGermany has prepared a preliminary standard DIN V 18 035-7 “Sportzplätze Teil 7: Kunststoffrasenflächen” (Sports areas – Part 7: Artificial turf pitches). Among other things, this standard established threshold values for the migration of heavy metals and dissolved organic compounds through specified analysis methods at laboratory scale in relation to limiting the possibility of soil and water pollution. It has been known to use analysis results from tests carried out in accordance with this preliminary standard as documentation for the environmental properties of infill materials for third-generation artificial turf. In Switzerland, there is criticism about the relevance of some of the tests of the German standard, as it is believed that it does not reflect reality in relation to established full-scale artificial turf pitches laid. One element of the critique has concerned acid leaching of heavy metals which has been thought to be unrealistic (H.J. Kolitzus, 2006). This reference also criticises the toxicity test. Switzerland (H.J. Kolitzus, 2006; E.Müller, 2007) has therefore initiated its own field measurements for leaching from artificial turf. As mentioned previously, this project was completed in 2007, but the report has not yet been published. Drafts also exists for German standards for the evaluation of dust properties, which can be used to assess infill for artificial turf pitches. These are DIM 33897-1, “Arbeitsplatzatmosphäre – Routineverfarhren zur bestimmung des Staubungsverhaltens von Schüttgütern – Teil 1: Grundlagen and Teil 3: Verstaubung in ruhender Luft” (Workplace atmosphere – Routine procedures for the determination of dust properties in infill – Part 1: Basics and Part 3: Dust properties in still air”. In prEN 15330-1, “Surfaces for sports areas – Synthetic turf and needle-punched surfaces primarily designed for synthetic turf”, a number of functional requirements for playing properties have been listed for artificial turf pitches, including football pitches. The standard also includes requirements for ageing resistance and water permeability as well as requirements that supplier list maintenance requirements. Both the ageing resistance and water permeability requirements can have an impact on the leaching rate and the leaching profile. The ageing of the artificial turf can have an impact on the availability of substances which can be leached, and the water permeability can impact the contact time between the materials of the artificial turf pitch and the rainwater. For measuring emissions from artificial turf pitches, several studies use the standard DS/EN ISO 16000 – 10 (2006): “Indendørsluft – del 10. Bestemmelse af emissionen af flygtige organiske substances fra byggematerialer og møbler - Emissionsprøvningsmetoden” (Indoor air - Part 10: Determination of the emission of volatile organic compounds from construction materials and furniture – Emission testing method). This study has used a simpler measurement of the headspace composition, corresponding to the screening method used in Norway. 4.2.4 Description of health exposure scenariosOn the basis of the chemical substances which are used for the structure of the artificial turf pitches, and the published results from the many foreign studies, the exposure scenarios have attempted to take the already existing knowledge and the particular Danish climate conditions into consideration. Furthermore, the scenarios include an assessment of the differences existing in connection with exposure through the respiratory passages with outdoor use, as the Norwegian studies are related to indoor use of the artificial turf pitches, because these are more common due to the colder climate. The principles of the assessments are based on the EU Technological Guidance Document (TGD) for risk assessments. The exposed users could be adults as well as children. The health assessments in this study and fact-finding project are based on the Norwegian exposure scenarios according to the worst case principle, but related to outdoor sports. The scenarios for inhalation, skin contact and oral intake are reviewed summarily below. It should be noted that, according to the French study, which is also based on indoor exposure as regards exposure through inhalation, no models exist for outdoor exposure within the relevant distance (the models use distances of 100 m up to 1 km radius from the area where the VOC emission takes place). This means that it comes down to pure estimation how much less the exposure is outdoors. According to the Danish Football Association (DBU), there is no major difference between the number of training and actual playing hours in Denmark and Norway. Therefore, as mentioned above, it is possible to use the Norwegian scenarios as a starting point. These are: 4.2.4.1 Inhalation
Body weight = 70 kg Inhalation volume during training/match = 6 m³/hour Duration per week = 20 hours Duration in months = 6 months In addition to this should be added six hours of match play per week for six months. This results in a weekly exposure volume of 156 m³/week for six months or 0.32 m³/kg body weight per day.
Body weight = 65 kg Inhalation volume during training/match = 4.8 m³/hour Per-exposure duration = 2 hours No. of exposure episodes per week = 7 Duration in months = 5.5 months In addition to this should be added two two-hour matches per month for three months. This results in a weekly exposure volume of 75 m³/week for 16 weeks or 0.16 m³/kg body weight per day.
Body weight = 50 kg Inhalation volume during training/match = 3.6 m³/hour Duration per week = 10 hours Duration in months = 6 months In addition to this should be added two hours of match play per week for six months. This results in a weekly exposure volume of 43.2 m³/week for six months or 0.12 m3/kg body weight per day.
Body weight = 30 kg Inhalation volume during training/match = 1.8 m³/hour Duration per week = 10 hours Duration in months = 6 months In addition to this should be added two hours of match play per week for six months. This results in a weekly exposure volume of 21.6 m³/week for six months or 0.10 m3/kg body weight per day. Health assessments were performed for the highest exposure and for the most sensitive user group (scenarios 1 and 4). 4.2.4.2 Skin contact
Body weight = 70 kg Skin surface exposed = 7,100 cm² Per-exposure duration = 4 hours No. of exposure episodes per week = 5 Duration in months = 6 months In addition to this should be added six hours of match play per week for six months. It is assumed that the matches take place in the same period as the training. This results in a weekly skin exposure of 42,600 mg of rubber granules per week or 87 mg of rubber granules per kg of body weight per day.
Body weight = 65 kg Skin surface exposed = 6,600 cm² Per-exposure duration = 2 hours No. of exposure episodes per week = 7 Duration in months = 5.5 months In addition to this should be added two two-hour matches in three months. It is assumed that the matches take place in the same period as the training. This results in a weekly skin exposure of 49,500 mg of rubber granules per week or 109 mg of rubber granules per kg of body weight per day.
Body weight = 50 kg Skin surface exposed = 5,100 cm² Per-exposure duration = 2.5 hours No. of exposure episodes per week = 4 Duration in months = 5.5 months In addition to this should be added two hours of match play per week for six months. It is assumed that the matches take place in the same period as the training. This results in a weekly skin exposure of 25,500 mg of rubber granules per week or 73 mg of rubber granules per kg of body weight per day.
Body weight = 30 kg Skin surface exposed = 3,000 cm² Per-exposure duration = 2.5 hours No. of exposure episodes per week = 4 Duration in months = 6 months In addition to this should be added two hours of match play per week for six months. It is assumed that the matches take place in the same period as the training. This results in a weekly skin exposure of 15,000 mg of rubber granules per week or 71 mg of rubber granules per kg of body weight per day. Health assessments were performed for the highest exposure (scenario 6). If the project results indicate a health risk, some of the other scenarios are added. 4.2.4.3 Oral intakeThere is no concrete knowledge on the extent to which children playing football on an artificial turf pitch will accidentally swallow some of the granulate. In the Norwegian study, the absolute worst case scenario was assumed to be somewhere between 23.7 mg per kg of body weight per day and 93.4 mg of rubber granules per kg of body weight per day for a duration of six months. The scenarios on which the estimated intake are based take an oral intake of 1.0 g of rubber dust per match as their starting point. It seems unrealistically high because of the unpleasant taste of rubber, but nonetheless serves as the worst case scenario. 4.2.5 Suggestions for exposure scenarios for migration to soil/waterIn this project, it was not possible to complete comprehensive tests including collection of drainage from lysimeters, neither based on a financial or a temporal evaluation. The foreign studies were typically conducted over a period of one year with monitoring of up to 42 analysis parameters. Therefore, this project has conducted relatively simple leaching tests, corresponding to those conducted in Norway (in accordance with prEN 12457-4 at L/S=10) or in accordance with the German DIN 18035-7. If possible, a comparative test was made in accordance with guidelines for leaching of heavy metals and salts from soil and cinders in Danish Executive Order no. 1635, 2006 on recycling of residual products and soil for construction works. The executive order for testing of soil (prEN 12457-3) uses a lower liquid content (L/S=2), which may be difficult to handle when testing rubber particles (prEN 12547-3). If this is taken into consideration, the method is otherwise deemed to be suitable for rubber. The leaching tests include leaching to demineralised water, a sodium chloride solution and a calcium chloride solution (alkaline pH). The starting point is the guideline volumes of salt which, according to DBU, are estimated to be used per year (2 tonnes), and the information gathered through interviews with football clubs, municipalities and artificial turf suppliers. The starting point is watering with a solution of salt in water at a ratio of 1:6. The samples (primarily infill) selected for migration tests would be the samples for which the risk was expected to be biggest for high migration of zinc, phthalates and octylphenols/nonylphenols or other substances which are harmful to human health. Based on the leaching tests, a simple assessment was made of the impact of substances in drainage water on drinking water quality by comparing the concentration of substances in the contact medium to drinking water requirements. Furthermore, the impact of any leaching of drainage water from football pitches into nearby watercourses was assessed, e.g. in case of heavy rainfall, and considerations were made on the significance of leached substances in relation to wastewater discharge. Comparative worst case reviews or simplified model observations were applied, as the financial framework of the project did not allow for comprehensive modelling which could take the actual soil conditions in connection with water recovery at the football pitches tested into consideration. Footnotes[3] Based on detailed information from one municipality, DBU’s figures in the maintenance guide must be expected to be somewhat unreliable in relation to the actual consumption of salt on some of the pitches.
|