Speciation of the UK Polychlorinated Biphenyl emission Inventory

Transcription

1 Speciation of the UK Polychlorinated Biphenyl emission Inventory A report produced for Department for Environment, Food and Rural Affairs, the National Assembly for Wales, the Scottish Executive and the Department of the Environment in Northern Ireland. C Conolly October 2001 AEA Technology ii

2 Title Customer Speciation of the UK PCB emission Inventory Department for Environment, Food & Rural Affairs, the National Assembly for Wales, the Scottish Executive and the Department of the Environment in Northern Ireland. Customer reference EPG 1/3/134 Confidentiality, copyright and reproduction Unclassified File reference Report number AEAT/R/ENV/0001 Report status Issue 1 AEA Technology Environment Culham Abingdon Oxfordshire OX14 3ED United Kingdom Telephone + 44 (0) Facsimile + 44 (0) AEA Technology is the trading name of AEA Technology plc AEA Technology is certificated to BS EN ISO9001:(1994) Name Signature Date Author Reviewed by Approved by Christopher Conolly Peter Coleman Mike Woodfield AEA Technology iii

3 Contents 1 Executive Summary 2 Introduction 3 Methods. 2.1 EMISSION ESTIMATES 2.2 SPECIATION Sources containing PCBs Combustion processes and other sources 4 Results 5 Discussion. 6 Recommendations. 7 References Appendices APPENDIX 1 APPENDIX 2 SPECIATION PRIOFILES NAEI OUTPUT OF ESTIMATED SPECIATED EMISSIONS AEA Technology iv

4 Executive Summary Polychlorinated biphenyls (PCB) have been widely used in a variety of industrial applications since they were first used industrially in the late 1920 s. Theoretically 209 different PCB congeners exist, however only about 100 individual congeners are likely to occur in significant quantities in commercial mixtures. Prior to this report the National Emissions Inventory (NAEI) reported PCB emissions as total PCB, there was no speciation. This study has produced estimated speciation for a large proportion (93%) of the estimated atmospheric emission. Speciated emission profiles have been produced for most of the major PCB emission sources, these include transformers, capacitors, landfills, fragmentisers, electric arc furnaces, industrial combustion, domestic combustion, and some agricultural combustion. These profiles are used in the NAEI to produce an estimate of the speciated emission of PCB congeners. AEA Technology v

5 Introduction Polychlorinated biphenyls (PCB) have been widely used in a variety of industrial applications since they were first synthesised in the late 1920 s. Theoretically 209 different PCB congeners exist, however only about 100 individual congeners are likely to occur in significant quantities in commercial mixtures. In production, the congener composition normally depends on the ratio of biphenyl to chlorine during the formation reaction however the distribution of individual PCBs can be different between production batches. The American multinational, Monsanto was the major manufacturer of PCBs in the UK before their production was discontinued in Monsanto marketed the PCB mixtures under the trade name of Aroclor followed by a four-digit number of which the last two digits usually described the percentage of the chlorine in the product. For example Aroclor 1256 had a chlorine content of 56% by weight, the mixture contained many congeners in varying concentrations. PCBs were also marketed in the UK under the trade name of Pyrochlors. In Europe commercial PCB mixtures were marketed under various trade names and produced by various manufacturers, some of the trade names used by reported 1 manufacturers are shown in Table 1. Table 1. Manufacturers and Trade Names for PCB Commercial Mixtures. Manufacturer Country Trade name(s) Monsanto UK Aroclor, Pyroclor Bayer A. G. Federal Republic of Germany Clophen, Elaol DSW-VEB German Democratic Republic Orophene Caffaro Italy Fenoclor, Pyralene S.A. Cros Spain Fenoclor,Pyralene Prodelec France Phenoclor, Pyraléne PCBs were extensively used in electrical equipment such as capacitors and transformers 1. Their use in open applications was widely banned in 1972 and they have not been used in the manufacture of new equipment since , plant that had been installed prior to 1986 was allowed to continue until the end of its working life. The PCBs currently found in the atmosphere are widely considered to result from the redistribution of PCBs already present in the environment, the release from transformers and capacitors and other PCB wastes at disposal sites and incineration of PCB-containing waste 3. Due to their extreme persistence, PCBs have been recognised as environmental contaminants since the mid 1960 s and are now ubiquitous in the environment 4. Before this report was produced, the UK National Atmospheric Emissions Inventory (NAEI) reported PCBs as total PCB. However, as individual PCBs have different levels and mechanisms of toxicity, it enhances the value of inventories if individual PCBs are reported. The World Health Organisation (WHO) have produced toxic equivalence factors (TEFs) for PCBs relative to 2,3,7,8 Tetrachlorodibenzo-p-dioxin, (2,3,7,8-TCDD). These factors are used to assess the dioxin-like toxicity of individual PCBs. The TEFs proposed in 1997 for PCB species are indicated in the Table 2. AEA Technology 1

6 Table 2: World Health Organisation Proposed TEFs for PCB congeners (1997). PCB Congener IUPAC TEF PCB number 34,3'4'-tetrachlorobiphenyl ,4'-tetrachlorobiphenyl ,3'4'-pentachlorobiphenyl ,3'4'5'-hexachlorobiphenyl ,3'4'-pentachlorobiphenyl ,4'-pentachlorobiphenyl ,3'4'-pentachlorobiphenyl ,2'4'-pentachlorobiphenyl ,3'4'-hexachlorobiphenyl ,3'4'5'-hexachlorobiphenyl ,3'4'5'-hexachlorobiphenyl ,3'4'5'-heptachlorobiphenyl The TEFs range over four orders of magnitude and cover just those 12 congeners which exhibit dioxin-like toxicity; the remainder may exhibit different mechanisms of toxicity. The observed difference in the toxicity of congeners means that inventories reporting total PCB could be misleading since the impact of each source could be different from that suggested solely by the total mass of PCB emitted and hence policy actions to abate releases misplaced. A speciated emissions inventory is therefore important. AEA Technology 2

7 Methods. 1.1 EMISSION ESTIMATES There are limited numbers of measurements speciating the atmospheric emissions of PCB. Where measurements have been made they are typically for a restricted range of PCB congeners. There have however been some studies which estimate the releases of PCBs to the UK environment, these have been completed by ETSU 3 and APARG 5. The ETSU estimates, being more recent, are considered the most accurate to date. The averages of the emission range given in the ETSU report 3 for each source are used in the NAEI, and are also used in this report. 1.2 SPECIATION Speciation is required both for sources which contain PCBs e.g. capacitors, and also for sources where PCBs are formed in situ, such as during combustion Sources containing PCBs Analyses of many commercially produced Aroclors have been reported in literature. The information from Schulz 7 was most extensive but some information from WHO was also used for NAEI purposes. A number of additional assumptions were made in order to develop speciated emissions profiles: the only Aroclors used in individual sources were as reported in Environmental Protection Bulletin 004. PCBs: Properties, Health Risks and Legislation 8 ; where a number of Aroclors were used in a source sector the ratio of each Aroclor used in the UK has been assumed to be the same as the US sales ratios found in De Voogt et al 1 ; the PCBs that are released from sources are identical to the congener ratios in the Aroclors which the sources contain; there was no selective release of particular PCB congeners from sources and no selective degradation or chemical changes of congeners occurs during the normal usage of Aroclors. American (USA) figures were used because UK figures were not available and as the major UK manufacturer of Aroclors was Monsanto, a US company, it seemed reasonable that the production of individual Aroclors were in the same ratios in the US and the UK. There is some uncertainty concerning the US sales figures and this leads to uncertainty in the emission profiles. The estimates made by De Voogt et al 1 have been used because a summary of available literature was carried out and estimates given. Without reliable UK sales data estimates it isn t possible to remove uncertainty in this area. The contribution of a particular congener from a particular Aroclor X to emissions from a source Y is calculated using the equation below: AEA Technology 3

8 A y Where: S = B R U A y is the Contribution to source Y of congener A from Aroclor X B is the fraction of congener A in Aroclor X S is the US sales *1 of Aroclor X U is the total US sales *1 of all the Aroclors used in source Y and R is the Release from the source per year. * sales from This calculation is completed for all of the Aroclors used in source Y and for all the congeners. The sum of congeners contributions from each of the Aroclors used in source Y is then calculated. Capacitors and Transformers releases. The PCB mixtures used in transformers and capacitors are not the same. The calculation shown above was used to estimate separate species profiles for releases from capacitors and transformers. These two profiles were, in turn, used to derive profiles for other emission sources that emit PCB congeners in the course of disposal of old transformers and capacitors, such as fragmentisers, landfill sites and electric arc furnaces. Fragmentisers and Landfill releases. PCB emission profiles for fragmentisers and landfill releases were assumed to be similar to releases from leaking capacitors of the type used in industrial and domestic appliances. Transformers were assumed not be included in the waste materials handled by fragmentiser plants and landfill sites. Electric Arc Furnaces releases. Estimates of emissions from electric arc furnaces have been calculated from the proportions of individual PCBs used in transformers and capacitors in the UK Processes Producing PCB Combustion Sources There is little information regarding speciated emissions of PCB formed during combustion and the Department of the Environment, Transport and the Regions (DETR) commissioned studies to produce improved estimates. The tests determined a number of congeners including the 12 PCBs with WHO toxic equivalent factors. Domestic combustion. Emission were quantified from a combustion unit burning seasoned hardwood and house coal in two separate tests. The 12 WHO PCB congeners plus an additional 38 congeners were analysed. It has been assumed, where the analysis indicated that there was co-elution of congeners, that the amount of each PCB co-eluting was equal. PCB emission profiles with all AEA Technology 4

9 of the PCBs analysed were constructed for each of the two fuels, domestic coal and domestic wood. Industrial Combustion. Tests were carried out at two locations within the UK: An industrial furniture manufacturing operation that burns the waste wood that is not used in the manufacturing process 9. A school in Yorkshire with a coal fired boiler providing heating and hot water to the school 10. The 12 WHO PCB congeners plus an additional 12 PCB congeners were analysed and profiles constructed for the two fuels: industrial coal and industrial wood. The concentrations of the individual PCB found in the flue gas were made into fractions of the overall PCB emissions measured to producing emission profiles for the two appliances. As with the domestic combustion sources, the only PCBs reported in the NAEI were those analysed. A full analysis of all of the 209 PCBs would be required to produce a full speciation. The individual profiles produced are given in Appendix 1, the profiles used for each source are shown in table 3. AEA Technology 5

10 Table 3. Summary of profile used for emission sources. Source Profile Used Agricultural Coal Combustion Agricultural Straw Combustion Application of Sewage Sludge to Land Basic Oxygen Furnaces Capacitor leakage Coal Combustion for Autogenerators Coke Production Combustion of RDF Combustion of Scrap Tyres Combustion of Waste Oils Domestic Coal Combustion Domestic Wood Combustion Electric Arc Furnaces Fragmentisers Incineration - Chemical Waste Incineration - Clinical Waste Incineration - Sewage Sludge Industrial Coal Combustion Industrial Wood Combustion Landfill Power Stations - Coal Power Stations - Municipal Waste Power Stations - Oil RDF Manufacture Sinter Plant Smokeless Solid Fuel Production Transformers Industrial Coal Unspeciated Unspeciated Unspeciated Capacitors/Fragmentisers/landfill Industrial Coal Industrial Coal Unspeciated Unspeciated Unspeciated Domestic Coal Domestic Wood Electric Arc Capacitors/Fragmentisers/Landfill Unspeciated Unspeciated Unspeciated Industrial Coal Industrial Wood Capacitors/Fragmentisers/Landfill Unspeciated Unspeciated Unspeciated Unspeciated Unspeciated Industrial Coal Transformer AEA Technology 6

11 Results The speciation profiles derived by this work and used in the NAEI are shown in Appendix 1. The speciation of >90% of the known PCB emission sources is shown in Table 4 together with an indication of the toxic equivalence values Table 4. Summary of PCB emission estimates in Source kg Total PCB % kg PCB Total TEF % (Total PCBTEF) Agricultural Coal Combustion <0.01 <0.01% 3.35E % Agricultural Straw Combustion 0.1 <0.01% Unspeciated Unspeciated Application of Sewage Sludge to Land % Unspeciated Unspeciated Basic Oxygen Furnaces % Unspeciated Unspeciated Capacitor leakage % 3.52E % Coal Combustion for Autogenerators % 7.12E % Coke Production % Unspeciated Unspeciated Combustion of RDF % Unspeciated Unspeciated Combustion of Scrap Tyres % Unspeciated Unspeciated Combustion of Waste Oils % Unspeciated Unspeciated Domestic Coal Combustion % 5.23E % Domestic Wood Combustion % 1.82E % Electric Arc Furnaces % 3.76E % Fragmentisers % 1.92E % Incineration - Chemical Waste % Unspeciated Unspeciated Incineration - Clinical Waste % Unspeciated Unspeciated Incineration - Sewage Sludge % Unspeciated Unspeciated Industrial Coal Combustion % 5.91E % Industrial Wood Combustion % 7.74E % Landfill % 2.44E % Power Stations - Coal % Unspeciated Unspeciated Power Stations - Municipal Waste % Unspeciated Unspeciated Power Stations - Oil % Unspeciated Unspeciated RDF Manufacture % Unspeciated Unspeciated Sinter Plant % Unspeciated Unspeciated Smokeless Solid Fuel Production % 3.08E % Transformers % 3.05E % Total E-02 AEA Technology 7

12 Discussion. Speciation has been completed for a large percentage (>90%) of the total estimated atmospheric emission; sources include transformers, capacitors, landfills, fragmentisers, electric arc furnaces, industrial combustion, domestic combustion, and some agricultural combustion. In the case of industrial and domestic combustion, the speciation only covers a limited set of the more toxic PCBs. At first glance, the high level of speciation of the PCB inventory (93% of PCB emissions by mass), would appear to ensure reasonably robust estimates of the total emissions expressed as TEQ. However, many of the data used to create the base inventory are estimates or assumptions, only a small number of congeners have TEFs and these congeners are present at very low concentrations in the commercial mixtures. As a result, care should be exercised when using the figures produced. At present the major source in terms both of total PCB and toxic equivalence (TEQ) is the leakage of material from capacitors and transformers. The source that presently appears to be second in terms of TEQ is industrial coal combustion; this appears to emit 11.7 % of the toxic equivalent but only 1.8 % of the total PCB. In contrast domestic coal combustion is estimated to emit 14.9 % of the total PCB but only 1.0 % of the TEQ. Given the similarity of the processes this suggests that measurement uncertainty is significant especially where only one set of tests is used to determine the PCB profile. US information have been used to create the PCB speciated profiles for capacitor and transformer releases by assuming that the fraction of the different commercial grades sold in the UK is the same as that in the US. It was also assumed that the composition of the grades was the same in the two countries. These assumptions have not been validated and investigation into recreating the historical situation while important to reduce uncertainty may no longer be possible. Other information needed to further improve the speciated emissions from the evaporative sources (such as landfills and sewage sludge to land.etc.) include: the age profile of disposed white goods and electrical items to enable an assessment of the PCB mixtures present, congener specific evaporation rates and chemical reactivity and degradation information to convert the release of PCBs into emission. AEA Technology 8

13 References 1. Production Properties and usage of PCBs P.DE VOOGT and U.A. Th Brinkmann. Elsevier Science Publishers B.V.(Biomedical Division).1989 pg Waste Management Paper No 6. Polychlorinated Biphenyl s. London HMSO. 3. Releases of PCBs to the UK environment Report to ETSU on Behalf of the DETR PCBs in the Environment. K. C. Jones, V. Burnett, Duarte-Davidson and K. S. Waterhouse. 5. Report on the Abatement of Toxic Organic Micropollutants (TOMPs) from Stationary Sources (1995) Air Pollution Review Group (APARG) Prepared at the request of the Air Quality Division, Department of the Environment. 6. Environmental Health Criteria 140. Polychlorinated Biphenyl s and Terphenyls (Second Edition). WHO Complete Characterisation of Polychlorinated Biphenyl Congeners in Commercial Arochlor and Clophen Mixtures by Multidimensional gas Chromatography-Electron Capture Detection. Detef E. Schulz, Gert Petrick and Jan C. Duinker. Environ Sci Technol., Vol. 23, No7, Polychlorinated Biphenyls: Properties Health risks and Legislation. B D Crittenden, et al 9. Thistlethwaite, G., Determination of Atmospheric Pollutant Emission Factors at a Small Industrial Wood Burning Furnace, AEA Technology, Report No AEAT/R/ENV/0518, March Thistlethwaite, G., Determination of Atmospheric Pollutant Emission Factors at a Small Coal-fired Heating Boiler, AEA Technology, Report No AEAT/R/ENV/0517, March 2001 AEA Technology 9

14 Appendices CONTENTS Appendix 1 Appendix 2 Speciation Profiles NAEI output of Estimated Speciated Emissions AEA Technology

15 Appendix 1 Speciation Profiles. The species profiles used in the NAEI are shown in the Tables below. Where no number is given, no analysis was carried out and no data are available. IUPAC Emission Profile PCB Transformer Capacitor, Fragmentisers, Landfill Electric Arc Domestic Coal E E E E E E E E AEA Technology

16 E E E E E E E E E E E E E E E E E AEA Technology

17 E E E E E E E E E E E E E E E E E E AEA Technology

18 E E E E E E E E E E E E-05 AEA Technology

19 E E E E E E E E E E E E E E E E E E AEA Technology

20 IUPAC PCB Emission Profile Domestic Wood Industrial Wood Industrial Coal AEA Technology

21 E AEAT/R/ENV/0001 Issue 1 AEA Technology

22 E AEAT/R/ENV/0001 Issue 1 AEA Technology

23 E AEAT/R/ENV/0001 Issue 1 AEA Technology

24 AEAT/R/ENV/0001 Issue 1 AEA Technology

25 Appendix 2 NAEI output of estimated speciated emissions. The following table gives emissions in kgrammes of each congener included in the species profiles for each source that can be speciated.

26 Source PCB Congener Coal combustion by agricultural sector E E E E E-05 Coal-fired autogeneration plant Leakage from capacitors Coal combustion at cement plant Coke ovens Coal combustion at collieries E E E E-05 Domestic coal combustion Domestic wood combustion Fragmentisers Coal combustion by the iron and steel sector E E E E-05 Electric arc furnaces Landfill sites Miscellaneous coal combustion E E E-05 Industrial coal combustion Industrial wood combustion Public services coal combustion Coal combustion by SSF manufacturers Transformers Total AEA Technology

27 Source PCB Congener Coal combustion by agricultural sector E E E E E-05 Coal-fired autogeneration plant Leakage from capacitors Coal combustion at cement plant Coke ovens Coal combustion at collieries E E E E E-05 Domestic coal combustion Domestic wood combustion Fragmentisers Coal combustion by the iron and steel sector E E E E E-05 Electric arc furnaces Landfill sites E-05 Miscellaneous coal combustion E E E E-05 Industrial coal combustion Industrial wood combustion Public services coal combustion Coal combustion by SSF manufacturers Transformers Total AEA Technology

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