Document O1BjQVapL2yoGYjvgkNJO4m6Q

OFFICIAL - SENSTIVE ENVIRONMENTAL RISK EVALUATION REPORT Substance Name: 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorohexane [1H-Perfluorohexane] Confidential Annex EC Number: CAS Number: 206-581-9 355-37-3 VERSION NUMBER: 1.0 DATE: October 2021 1 OFFICIAL - SENSTIVE The information in this Annex comes from the EU REACH registration dossier (ECHA, 2020) unless stated otherwise (see the main evaluation report for further details). EXPOSURE ASSESSMENT The information in this section is based on the Chemical Safety Report (CSR) submitted by the REACH Registrant to ECHA, supplemented with other information (e.g. from further dialogue with the Registrant) where available. Table CA1 Registrants CSR volumes Year Quantity imported /t 2018 22.5 33 (used 28.6) 2019 22.5 36 (used 30.9) 2020 22. 5 18 (used 29.9) 2021 37.5 (used 27.7) 1. Short description of exposure scenarios and measures for reducing emissions to the environment 1.1 Polymer manufacture This overview is based on information supplied by AGC Chemicals Europe, Ltd. (AGCCE Ltd). 1H-Perfluorohexane (1,1,1,2,2,3,3,4,4,5,5,6,6- tridecafluorohexane, C6H, ASAHIKLINTM AC-2000, EC Number: 206- 581-9 / CAS 355-37-3) is manufactured in Japan and imported to UK (AGCCE Ltd, Fleetwood Road North, Thornton-Cleveleys, Lancashire, FY5 4QD). 1H-Perfluorohexane is used exclusively at this site as a polymerisation solvent in the solution / precipitation type of polymerisation process to make poly(tetrafluoroethylene-co-ethylene) (ETFE). 1H-Perfluorohexane is also used as a diluent to polymerisation initiator in the reactor agitator sealant unit. ETFE manufacture involves two production lines and the manufacturing of ETFE consists of: 1. Polymerisation reaction which involves reaction of TFE, ethylene and 3,3,4,4,5,5,6,6,6- nonafluorohexene (PFBE) in the recycled 1H-perfluorohexane in the presence of chain transfer additive (methanol) and initiator. This is carried out in the reactor at constant elevated temperature and constant elevated pressure. The result is ETFE slurry. At the end of polymerisation someapproximately 50% of the unreacted monomer and <1% of solvent vapour is recovered as a vapour. 2. The purification process involves formation of ETFE beads in water and recovery of the reminder st of the unreacted monomers as well as evaporation of approximately 2 Formatted: Justified Formatted Table Commented [MS1]: Ethylene-tetrafluorethylene copolymer OFFICIAL - SENSTIVE 99 % of 1H-perfluorohexane solvent which is then condensed and recovered to solvent vessels. The recovered solvent is reused in the next batch of polymerisation. This process is carried out at elevated temperature. Recovered 1H-perfluorohexane is distilled off further at elevated temperature to reduce level of hydrocarbon (initiator solvent). The remaining monomer is recovered at this stage. 3. Drying involves draining of water and drying ETFE beads at elevated temperature and under vacuum. Water from this process is heated to remove the alcohol and contains trace 1H-perfluorohexane. This contaminated water is then transferred to the ETFE effluent pit, an underground lined open topped tank at a temperature of 90 oC. Any gaseous 1H-perfluorohexane residing in the headspace is captured using carbon beds and recovered back to recycled solvent tanks as liquid. There is also potential for release of the 1H-perfluorohexane to the atmosphere from this tank as the top is not sealed. The water from this tank is then transferred for distillation to remove the methanol, some of the 1H-perfluorohexane is also removed in this step. The condensed water remaining after the distillation is then transferred to the ETFE waste water tank prior to transfer to the onsite effluent tank for discharge into the river Wyre. 4. Finishing process involves two types of processes. ETFE beads are either packed off at this stage and sold to customers or processed further by extrusion. If processed by extrusion, ETFE melted at high temperature in the extruder, made into strands that are then cooled in water bath before being cut into pellets. ETFE pellets are degassed to remove HF, then packed and sold to customers. ETFE production is a closed batch process and continuous batch process and almost all of the 1H-perfluorohexane is recovered and reused repeatedly. Vessel is topped up by virgin 1H-perfluorohexane about once per month. The process flow diagram is shown in figure 1. Figure 1 ETFE manufacturing process diagram 3 OFFICIAL - SENSTIVE Formatted: Centered Note: 1H-Perfluorohexane is known as AC-2000 in this figure. During this evaluation work ACGCE completed the mass balance for 2020, the last 3 years mass balances are shown in table CA2. These mass balances are based on the quantities of raw materials used and ETFE manufactured and sampling at a number of the process release points. The details of releases to each compartment is discussed in more detail below. The releases to the atmosphere are an estimate based on the Table CA2 mass balance supplied by AGCCE Purchased Total emissions Abnormal events Used Recycled as part of the process Encapsulated into the polymer Destroyed by the thermal oxidiser Emitted to atmosphere Emitted to the river Emitted to landfill Captured for off-site disposal by incineration 2018 33 28.6 0.2 23,207 23,178 0.07 0.3 18.8 - 25.7 1.4 0.07 n/a Amount Tonnes/year 2019 2020 36 18 30.9 29.9 0 4.2 25,007 20,990 24,976 20,960 0.08 0.04 0.8 0.5 19.2 - 28.7 0.2 0.23 n/a 18.6 - 29.3 0 0.08 n/a 2021 37.5 27.9 0 21047 21018 1.2 0.6 24.5 0.035 0.84 0.75 Commented [EL2]: Seems like part of the sentence is missing Commented [MS3R2]: Confirmed missing from originally shared document. Expect it to say `the AC-2000 mass balanced shared by AGCCE' or words to a similar effect. Commented [MS4]: Calc by MJS: 1498 bx in 2021, average charge of AC-2000 (2018-2020) is 14.05 t. Commented [MS5]: Calc by MJS: Used - total emissions - destroyed by TO - captured for off-site disposal. 4 OFFICIAL - SENSTIVE AGCCE did not undertake an exposure assessment in their registration as 1Hperfluorohexane is not classified and it was registered in the 10-100 tonnage band, there is therefore no assessment of releases through out the life cycle of the products manufactured. Routes of emission to air The process water containing trace 1H-perfluorohexane is transferred from the manufacturing plant drying process into the ETFE pit, an underground lined tank. Most of the gaseous 1H-perfluorohexane residing in the headspace is captured using carbon beds using vacuum and recovered back to recycled solvent tanks as liquid, some of the substance is also released into the atmosphere. During this evaluation work AGCCE undertook a mass balance for 2020 and the estimate for releases from this tank were 1.17 tonnes in 2020, which equates to 3.5 kg/day based on site operation of 330 days per year. Monitoring of the releases from the carbon bed estimated a release of 7.48 tonnes in 2020, which equates to a release of 22.4 kg/day based on site operation of 330 days per year. The remaining quantity of releases to the atmosphere are based on the difference between the known releases and the quantity of 1H-perfluorohexane purchased each year to replace the lost substance, which is a total of 30.9 tonnes in 2019, which equates to 93.6 kg/day. 5 OFFICIAL - SENSTIVE Routes of emission to water The emissions to water are the process water used during the polymerisation of the ETFE. AGCCE take monthly samples from each of the tanks to monitor the levels of 1Hperfluorohexane, however the analytical method being used by the company is unreliable and the company does not have any confidence in the results obtained. The figures used in the mass balance for 2018 and 2019 were based on results above the aqueous solubility of 1H-perfluorohexane, so while the company has included the numbers in the mass balance they have not been used in the Environment Agency's evaluatuon. The company has recently employed a new analytical chemist to work on the method, to develop a more robust mass balance and increase AGCCE's understanding of the emissions from the ETFE plant. In the absence of any reliable monitoring data the Environment Agency has used the water usage in the manufacturing plant and the solubility of 1H-perfluorohexane to produce a worse case exposure scenario. Table 2 shows the volumes of water used in the ETFE plant, this process water is used in the polymerisation reactor, and is removed following the completion of the reaction. It passes through 2 heating processes to remove the methanol and recover the 1H-perfluorohexane. It is likely that some of this water is lost during these heating processes, but for the purposes of this evaluation we are assuming that all of the water used passes through into the waste water tanks and contains 1.5 mg/L of 1H-perfluorohexane as it enters the main effluent tank. The volumes used in the process are in table CA3. This will give the maximum possible quantity of 1H-perfluorohexane released from the site. Table CA3 volume of water used in the ETFE manufacturing process Year 2018 2019 2020 2021 Volume used m3 20,150 22,295 17,105 18,813 Using the volume of water used in 2019, the volume of 1H-perfluorohexane released was 33.443 kg. The release per day was 0.101 kg/day based on 330 days of operation a year, this is the figure used in the exposure modeling. Routes of emission to waste The mass balance gives a figure of 230 kg of 1H-perfluorohexane sent for offsite landfill. As this figure is so low releases to landfill arising from solid waste disposal were not considered further. 2. Release assumptions made by the Environment Agency AGCCE supplied a range of information to the Environment Agency, including the mass balance, process descriptions and some limited monitoring. As the data was limited the 6 Commented [MS6]: Should be re-worded! For example, "the analytical method being used by the company is unreliable and the company working to improve the reliability of this method." Commented [MS7]: Table CA3 OFFICIAL - SENSTIVE release assumptions for releases to water are the maximum possible and the release to atmosphere has been done using the highest value which was 2019, no additional scenarios were modelled. As 1H-perfluorohexane is continually recovered and reused in the site the numbers used for the modelling were the annual releases to each compartment. 2.1 Exposure scenarios ES 1: Industrial use - polymer manufacture Volume released: 30.933 tonnes (based on 2019 data). Number of emission days: 330 days/year (CSR). Releases to surface water: The quantity released to surface water in 2018 was 33.443 kg, based on the volume calculated above. - Effluent flow: The average daily volume of effluent discharged to the River Wyre was 803 m3/day in 2018 and 892 m3/day in 2019 (company data). The Environment Agency has assumed that the 2019 average daily flow of 892 892 m3/day is representative of current operations. - River flow: River flows are measured/calculated at an Environment Agency gauging station which lies roughly 16 km upstream of the AGCCE site (St Michael's flow monitoring station at national grid reference SD4633041131). The catchment at this station is tidally influenced, but the tidal peaks have been edited out by the Hydrometry and Telemetry Officer who is responsible for the site. The long-term daily mean flow was 6.67 m3/s, which equates to 576 288 m3/day. The 95th percentile low flow was 0.61 m3/s, which equates to 52 52 704 m3/day, and this is the figure that is used in this evaluation. This results in a dilution factor of 60. - Marine dilution factor: For sites that discharge direct to the marine environment, a marine dilution factor can be used. The default is 100. In this case, the site discharges to a river which is under tidal influence, and the estuary is nearby. It could be argued that the marine dilution factor might be more relevant. The Environment Agency has no information about the level of dilution in the estuary of the River Wyre. Therefore both the river dilution factor and the marine dilution factor will be applied separately. Releases to land: As explained in Section 2.1, there is no release to agricultural land (e.g. via spreading of sewage sludge) from this site. There may be some local deposition from atmospheric releases. Releases to air: The mass balance shows a release of 30.9 tonnes per year to the atmosphere from various points in the water handling process. This results in an emission of 93.6 kg per day based on operation of 330 days per year. ES 2: Industrial use - polymer processing 7 OFFICIAL - SENSTIVE The quantity of 1H-perfluorohexane in the fluoropolymer products supplied to customers was <0.08 tonnes, based on the information supplied in the mass balance. The Environment Agency considers that, as a worst case, all residual 1H-perfluorohexane can be assumed to be completely released during the polymer processing stage at their customers' sites to the atmosphere. The Environment Agency has assumed that there is no abatement to remove the 1H-perfluorohexane from these downstream users' sites. The entire tonnage can also be assumed to be released within the UK (which is also a worst case as the products are supplied outside the UK too). The fraction of main local source is set to the EUSES default of 0.5, in the absence of any additional information to refine this figure. The number of release days is 20 days/year as defined in the by ECHA R.16. Guidance Document (ECHA, 2016a). 2.2 Industrial, professional and consumer end-use The ETFE is a thermoplastic used for wire coatings, cables and tubings where the chemical and mechanical resistance is required. It is also used to produce thin films which are used as protective films for solar panels and membrane structure roofs such as sports stadiums and green houses. 3. Predicted Environmental Concentrations (PECs) The information in the confidential annex was used to estimate PECs in various types of environmental media using the EUSES model (version 2.0.3) for the various life cycle stages. The tonnage, release rates and physico-chemical properties are input parameters, and the relevant information for polymer manufacture is summarized in Tables CA4 and CA5. Table CA4 Substance-specific input parameters for the EUSES model Parameter Molecular weight Vapour pressure Water solubility at 20 C Octanol-water partition coefficient (log Kow) Octanol-carbon partition coefficient (log Koc) Values assumed by the Environment Agency 338.04 g/mol 15 kPa at 25 C 1.5 mg/L 4.1 3.7 Note: See Sections 2, 6 and 7 of the main report for the origin of these values. Table CA5 Scenarios used for the exposure assessments Parameter Annual release at site Emission days Daily release at site Scenario Current 30.933 tonnes/year 330 days/year 0.085 tonnes/day 8 Commented [MS8]: Note, UK ETFE sales have typically been less than 1 % of our global ETFE sales. Commented [MS9]: MW of AC-2000 is 320.05 g/mol (as reported in Table 1.1 in the main evaluation dossier. MW reported here is that of C6F14. Does this error impact any of the subsequent data in the resulting tables? OFFICIAL - SENSTIVE Regional release to surface water Percentage of tonnage used at regional scale Local release to atmosphere Receiving surface water flow rate Effluent discharge Downstream user fluoropolymer releases to atmosphere 0.033 tonnes/year 100% 30.9 tonnes per year 52 704 m3/day 893 m3/day <0.08 tonnes/year Table CA6 Local PECs calculated by the Environment Agency Life cycle stage Compartment PEC Unit Polymer manufacture Fresh surface water 1.7 x 10-3 mg/L Freshwater sediment 0.206 mg/kg ww Marine surface water 1.02 x 10-3 mg/L Marine sediment 0.123 mg/kg ww Air 0.234 mg/m3 Soil 5.81 x 10-5 mg/kg ww Groundwater* 1.95 x 10-7 mg/L Polymer processing Fresh surface water 1.26 x 10-6 mg/L (dispersion) Freshwater sediment 1.79 x 10-3 mg/kg ww Marine surface water 3.57 x 10-7 mg/L Marine sediment 2.04 x 10-4 mg/kg ww Air 0.21 mg/m3 Soil 6.54 x 10-5 mg/kg ww Groundwater* 1.67 x 10-7 mg/L Note: ww - wet weight * The porewater concentration for agricultural soil is used to represent groundwater. RISK CHARACTERISATION The Environment Agency has estimated PECs arising from the use of 1H-perfluorohexane in the manufacture of fluoropolymer and the downstream user scenarios for EFTE that contain it in residual amounts. These can be compared to the predicted no effect concentrations (PNECs) derived in Section 10 of the main report. The risk characterisation ratios (RCRs) derived by the Environment Agency is shown in table CA7. An RCR above 1 indicates a potential risk. 9 OFFICIAL - SENSTIVE Table CA7 Risk characterisation ratios calculated by the Environment Agency Life cycle stage Polymer manufacture Polymer processing (dispersion) Regional Fresh water 0.125 1.09 x 10-3 2.57 x 10-5 Marine water 0.751 1.24 x 10-3 1.8 x 10-4 Secondary poisoning fish 8.38 x 10-3 8.11 x 10-6 The Registrant did not conclude on whether their release constituted an environmental risk as they did not undertake an exposure assessment and they were not required to do one under REACH. The modelling indicates RCR below 1 for the fresh water and marine compartments arising from the polymer manufacturing site. There is significant uncertainty on the releases to the river Wyre, the quantity was estimated based on the solubility of 1H-perfluorohexane. This does not take into account any losses to the environment during the heating and distillation stages of the recovery of methanol and 1H-perfluorohexane or the vacuum extraction of the gases in the headspace into the carbon bed recovery unit. Due to this heating the actual concentration in the waste water being discharged into the site effluent tank is likely to be significantly lower than the solubility. We recommend that AGCCE refines the analytical method used for monitoring this aqueous waste stream and undertakes a monitoring campaign prior to refining the exposure assessment. As there is a significant uncertainty to the quantities allocated to each compartment we recommend further work to understand the emissions from each part of the process. Further refinement of the exposure assessment is recommended, with particular emphasis on the monitoring of the releases to the river Wyre and if a risk is indicated then refinement of the dilution factor and/or measurement of concentrations in the receiving waters. AGCCE has committed to identification and reduction of the releases from the use of 1Hperfluorohexane. Below is text from a document shared by AGCCE during the production of this evaluation. "1H-perfluorohexane is a compound that is not easily assessed and monitored for multiple reasons. Analytical methods still need to be further developed and refined. The ETFE manufacture process itself, combined with the high volatility of 1H-perfluorohexane, could potentially lead to air emissions that still need to be both identified and quantified. The mass balance assessment used in combination with the available data clearly indicate that further work and research needs to be done to better understand the 1H-perfluorohexane emissions related to the manufacture of ETFE at our Hillhouse plant. AGCCE is therefore committed to engage into an R&D program aiming at the identification of all 1H-perfluorohexane sources of atmospheric emissions. Once identified and quantified, AGCCE will be implementing and/or developing the best available technologies to reduce emissions to the atmosphere." 10