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Indirect Precursors of Perfluorobutanesulfonate (PFBS): Human health tier II assessment

13 February 2015

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Chemicals in this assessment

Chemical Name in the Inventory CAS Number
2-Propenoic acid, 2-[ethyl[(nonafluorobutyl)sulfonyl]amino]ethyl ester 17329-79-2
1-Butanesulfonamide, N-ethyl-1,1,2,2,3,3,4,4,4-nonafluoro-N-(2-hydroxyethyl)- 34449-89-3
1-Butanesulfonamide, 1,1,2,2,3,3,4,4,4-nonafluoro-N-(2-hydroxyethyl)-N-methyl- 34454-97-2
1-Butanesulfonamide, 1,1,2,2,3,3,4,4,4-nonafluoro-N,N-bis(2-hydroxyethyl)- 34455-00-0
1-Propanaminium, N,N,N-trimethyl-3-[[(nonafluorobutyl)sulfonyl]amino]-, chloride 53518-00-6
1-Butanesulfonamide, N-[3-(dimethylamino)propyl]-1,1,2,2,3,3,4,4,4-nonafluoro-, monohydrochloride 68957-59-5
Glycine, N-ethyl-N-[(nonafluorobutyl)sulfonyl]-, potassium salt 67584-51-4
Ethanol, 2-[ethyl[(1,1,2,2,3,3,4,4,4-nonafluorobutyl)sulfonyl]amino]-, dihydrogen phosphate (ester) 67939-89-3
1-Propanaminium, N,N,N-trimethyl-3-[[(nonafluorobutyl)sulfonyl]amino]-, iodide 67939-95-1
Poly(oxy-1,2-ethanediyl), .alpha.-[2-[ethyl[(nonafluorobutyl)sulfonyl]amino]ethyl]-.omega.-hydroxy- 68298-79-3
Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-[2-[ethyl[(nonafluorobutyl)sulfonyl]amino]ethyl]-.omega.-hydroxy- 68310-18-9
Benzoic acid, 2,3,4,5-tetrachloro-6-[[[3-[[(nonafluorobutyl)sulfonyl]oxy]phenyl]amino]carbonyl]-, monopotassium salt 68568-54-7
Chromium, diaquatetrachloro[.mu.-[N-ethyl-N-[(nonafluorobutyl)sulfonyl]glycinato-O1:O1']]-.mu.-hydroxybis[2-propanol]di- 68900-97-0

Preface

This assessment was carried out by staff of the National Industrial Chemicals Notification and Assessment Scheme (NICNAS) using the Inventory Multi-tiered Assessment and Prioritisation (IMAP) framework.

The IMAP framework addresses the human health and environmental impacts of previously unassessed industrial chemicals listed on the Australian Inventory of Chemical Substances (the Inventory).

The framework was developed with significant input from stakeholders and provides a more rapid, flexible and transparent approach for the assessment of chemicals listed on the Inventory.

Stage One of the implementation of this framework, which lasted four years from 1 July 2012, examined 3000 chemicals meeting characteristics identified by stakeholders as needing priority assessment. This included chemicals for which NICNAS already held exposure information, chemicals identified as a concern or for which regulatory action had been taken overseas, and chemicals detected in international studies analysing chemicals present in babies’ umbilical cord blood.

Stage Two of IMAP began in July 2016. We are continuing to assess chemicals on the Inventory, including chemicals identified as a concern for which action has been taken overseas and chemicals that can be rapidly identified and assessed by using Stage One information. We are also continuing to publish information for chemicals on the Inventory that pose a low risk to human health or the environment or both. This work provides efficiencies and enables us to identify higher risk chemicals requiring assessment.

The IMAP framework is a science and risk-based model designed to align the assessment effort with the human health and environmental impacts of chemicals. It has three tiers of assessment, with the assessment effort increasing with each tier. The Tier I assessment is a high throughput approach using tabulated electronic data. The Tier II assessment is an evaluation of risk on a substance-by-substance or chemical category-by-category basis. Tier III assessments are conducted to address specific concerns that could not be resolved during the Tier II assessment.

These assessments are carried out by staff employed by the Australian Government Department of Health and the Australian Government Department of the Environment and Energy. The human health and environment risk assessments are conducted and published separately, using information available at the time, and may be undertaken at different tiers.

This chemical or group of chemicals are being assessed at Tier II because the Tier I assessment indicated that it needed further investigation.

For more detail on this program please visit:www.nicnas.gov.au

Disclaimer

NICNAS has made every effort to assure the quality of information available in this report. However, before relying on it for a specific purpose, users should obtain advice relevant to their particular circumstances. This report has been prepared by NICNAS using a range of sources, including information from databases maintained by third parties, which include data supplied by industry. NICNAS has not verified and cannot guarantee the correctness of all information obtained from those databases. Reproduction or further distribution of this information may be subject to copyright protection. Use of this information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner. NICNAS does not take any responsibility whatsoever for any copyright or other infringements that may be caused by using this information.

Grouping Rationale

The chemicals in this group are structurally related compounds in that they all contain a chain of four perfluorinated carbons linked to a terminal sulfonamide or sulfonic ester group.

The assessment of this group has been conducted in accordance with the NICNAS Action Plan for Assessment and Management of Chemicals which may degrade to Perfluorinated Carboxylic Acids, Perfluoroalkylsulfonates and similar chemicals (the Action Plan). The primary assumption outlined in the Action Plan is that chemicals with a perfluorinated chain terminated by a sulfonyl group will degrade to the perfluoroalkylsulfonate. More information on the plan can be found in Appendix G of the NICNAS Handbook for Notifiers (see NICNASa).

On this basis, the chemicals in this group are considered to have the potential to release the environmentally persistent perfluorobutanesulfonate (PFBS) anion via biodegradation and, therefore, are considered to be PFBS precursors.

PFBS based chemicals were introduced as alternatives to the longer chain perfluoroalkyl sulfonates (PFAS) (containing carbon chain lengths of 6 or higher) including substances which may be a source of the hazardous perfluorooctanesulfonate (PFOS) anion in the environment (UNEP, 2013). As the critical health concerns for the longer chain PFAS chemicals are bioaccumulation potential and systemic long term effects (NICNASb), the focus of this assessment for the shorter chain PFBS chemicals will be on their potential for similar long term effects. Data for acute and local effects have been included where available.

The degradation of PFBS is very slow compared with its rate of formation from degradation of the precursors and PFBS will be the final degradant from multiple precursors. Therefore, the amounts of the PFBS in the environment (general or local) is expected to be higher than that of any of the precursors. Whilst polymeric precursors generally do not present significant risks while in polymeric form, direct exposure to small molecule precursors, such as those in this assessment, may pose health risks. However, these are generally used in small volume and/or low concentrations in Australia (see Australian Import, Manufacture and Use section). Consequently, the most important health risk is expected to arise from secondary exposure to PFBS.  As such, the focus of this assessment is on the long term effects of the chemicals due to the degradation of the chemicals to PFBS. Acute and local effects have not been considered.

Australian

The 3M company is the primary producer of substances based on PFBS technology internationally (Poulsen, et al., 2005; UNEP, 2013). Based on the available information, only one of these chemicals is currently used in one specific application (specialised printing ink) at very low volumes (less than 1 kg per annum).

Information collected under NICNAS in 2005 indicated that no PFBS derivatives were manufactured in Australia (NICNAS, 2005).

It is noted that the chemicals in this group may be present in the environment due to historic use, or due to release from articles or the use of chemicals not covered by this assessment.

International

Some of the chemicals in this group (CAS Nos. 34454-97-2, 67584-51-4, 67939-95-1, 68298-79-3, 68310-18-9 and 68900-97-0)) are used as surfactants. No other specific uses were identified (Galleria Chemica).

The use of PFBS derivatives as an alternative to the use of PFOS has been identified for the following uses (Poulsen et al. 2005; UNEP, 2013):

  • impregnation of textiles, leather and carpets;
  • industrial and commercial cleaning products;
  • surface coatings, paints and varnishes;
  • oil production and mining;
  • semiconductor industry; and
  • electroplating.

These uses are considered potentially relevant to the chemicals in this group.

Use data available for Nordic countries indicate that N-MeFBSE alcohol, potassium N-EtFBSA acetate and the quaternary ammonium iodide salt (CAS RN 67939-95-1) were in use in Denmark in 2012. Additionally, PEG N-EtFBSE was used in Denmark in 2011. Other chemicals in this group were used in preceding years. Identified uses include surface treatment and as a surface-active agent and cleaning agent (SPIN).

All chemicals in this group, except PPG N-EtFBSE (CAS No. 68310-18-9), are pre-registered under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation. None of these chemicals are registered under the REACH legislation.

No evidence of the presence of these chemicals in consumer products was found in available North American databases, indicating that the chemicals are not likely to be widely available for domestic uses.

Australian

No known restrictions have been identified. However, substances with shorter per- or polyfluorinated carbon chain have been developed as a strategy to replace long chain alkyl substances.

International

No known restrictions have been identified.

Existing Worker Health and Safety Controls

Hazard Classification

The chemicals are not listed on the Hazardous Substances Information System (HSIS) (Safe Work Australia).

Australian

No specific exposure standards are available.

International

No specific exposure standards are available.

No data are available for the chemicals in this group. The chemicals in this group are assumed to degrade to PFBS. The primary health risk for the chemicals in this group is expected to arise from secondary exposure to PFBS (see Grouping Rationale section).

PFBS was shown to actively bind to human albumin protein in serum. Apparent saturation of the binding above 100 ppm in rat, human and monkey serum was observed in this study. In comparison to PFOS, PFBS is eliminated by various species within shorter periods of time. Increased levels of PFBS have been found in blood and serum of humans in some (but not all) countries (NICNASc). No data are available on the levels of PFBS in the Australian population.

PFBS is not considered to be acutely toxic or cause serious damage to health from repeated oral exposure including reproductive or developmental toxicity. It is not considered to be genotoxic. There are no available data on the carcinogenicity of PFBS. Whilst PFOS is classified as hazardous with the risk phrase Carc. Cat 3 - Limited evidence of a carcinogenic effect (Xn; R40) (NICNASb), histopathological changes (both neoplastic and non-neoplastic) observed in 90-day studies with PFOS at the sites of tumour formation were not observed in studies using PFBS (NICNASc).

Critical Health Effects

The focus of this assessment is on the long term effects of the chemicals due to the degradation of the chemicals to PFBS. Acute and local effects (irritation and sensitisation) have not been considered. Whilst polymeric precursors generally do not present significant risks while in polymeric form, direct exposure to small molecule precursors, such as those in this assessment, may pose health risks. However, these are generally used in small volume and/or low concentrations in Australia (see Australian Import, Manufacture and Use section). Consequently, the primary health risk is expected to arise from secondary exposure to PFBS.  

Data available indicate that PFBS has a more favourable toxicological profile and bioaccumulation potential than long-chain perfluoroalkyl substances. Chronic low level effects on human health have not been identified.

Public Risk Characterisation

Use in consumer products

Based on the available use information, the chemicals are not likely to be available for domestic or cosmetic uses. Hence, the public risk from direct use of these chemicals is not considered to be unreasonable.

Secondary exposure to PFBS via the environment

Public exposure to PFBS could occur through secondary exposure via the environment. It is noted that PFBS has been found to be a highly persistent chemical, and environmental levels may continue to increase over time due to release from various sources. The scale and time frame of such an increase, and its relevance to characterising the long term environmental risk profile of PFBS, currently remain unknown (NICNASd).

Data available indicate that PFBS has a more favourable toxicological profile and bioaccumulation potential than the long-chain perfluoroalkyl substances. Chronic low level effects on human health have not been identified. Further assessment of the chemicals in this group may be necessary to inform the risk of secondary exposure to PFBS, if:

  •  information becomes available indicating that these chemicals are introduced into Australia in significant quantities; or
  • hazard data become available indicating adverse health effects.

Occupational Risk Characterisation

Based on the available use information, the chemicals are not likely to be used in significant quantities in Australia. Therefore the chemicals are not considered to pose an unreasonable risk to the health of workers.

The chemicals currently have no hazard classification for worker health and safety; this is considered appropriate for systemic long-term effects based on available data. Acute and local effects (irritation and sensitisation) have not been considered.

NICNAS Recommendation

Current risk management measures are considered adequate to protect public and workers’ health and safety, provided that all requirements are met under workplace health and safety, and poisons legislation as adopted by the relevant state or territory.

The chemicals are not recommended for classification and labelling under the current approved criteria and adopted GHS. This does not consider classification of acute toxicity, local effects (irritation and sensitisation), physical hazards and environmental hazards.

Further assessment of the chemicals in this group may be necessary to inform the risk of secondary exposure to PFBS, if:

  •  information becomes available indicating that these chemicals are introduced into Australia in significant quantities; or
  • hazard data become available indicating adverse health effects.

Advice for industry

Obligations under workplace health and safety legislation

Information in this report should be taken into account to assist with meeting obligations under workplace health and safety legislation as adopted by the relevant state or territory. This includes, but is not limited to:

  • ensuring that hazardous chemicals are correctly classified and labelled;
  • ensuring that (material) safety data sheets ((m)SDS) containing accurate information about the hazards (relating to both health hazards and physicochemical (physical) hazards) of the chemical are prepared; and
  • managing risks arising from storing, handling and using a hazardous chemical.

Your work health and safety regulator should be contacted for information on the work health and safety laws in your jurisdiction. Information on how to prepare an (m)SDS and how to label containers of hazardous chemicals are provided in relevant codes of practice such as the Preparation of Safety Data Sheets for Hazardous Chemicals— Code of Practice and Labelling of Workplace Hazardous Chemicals—Code of Practice, respectively. These codes of practice are available from the Safe Work Australia website.

A review of the acute toxicity, local effects and physical hazards of the chemicals has not been undertaken as part of this assessment.

References

National Industrial Chemical Notification and Assessment Scheme (NICNASa). Data requirements for notification of new chemical substances containing a perfluorinated carbon chain. Available at https://www.nicnas.gov.au/notify-your-chemical/data-requirements-for-new-chemical-notifications/data-requirements-for-notification-of-new-chemicals-containing-a-perfluorinated-carbon-chain

National Industrial Chemicals Notification and Assessment Scheme (NICNAS, 2005). Existing Chemicals hazard assessment report on potassium perfluorobutane sulfonate. Available at http://www.nicnas.gov.au

National Industrial Chemicals Notification and Assessment Scheme (NICNASb). Tier II human health assessment for Perfluorooctanesulfonate and its direct precursors Australian Government Department of Health. Available at http://www.nicnas.gov.au

National Industrial Chemicals Notification and Assessment Scheme (NICNASc). Tier II human health assessment for Perfluorobutanesulfonate and its direct precursors. Australian Government Department of Health. Available at www.nicnas.gov.au

National Industrial Chemicals Notification and Assessment Scheme (NICNASd). Tier II environment assessment for Perfluorobutanesulfonate and its direct precursors. Australian Government Department of Health. Available at www.nicnas.gov.au

OECD (2013), OECD/UNEP Global PFC Group, Synthesis paper on per- and polyfluorinated chemicals (PFCs), Environment, Health and Safety, Environment Directorate, OECD. Accessed January 2015 at http://www.oecd.org/env/ehs/risk-management/PFC_FINAL-Web.pdf

Poulsen PB, et al. (2005). More environmentally friendly alternatives to PFOS-compounds and PFOA. Danish Environmental Protection Agency, Cophenhagen, Denmark. Accessed 21 January 2015 at http://www2.mst.dk/udgiv/publications/2005/87-7614-668-5/pdf/87-7614-669-3.pdf.

Safe Work Australia (SWA). Hazardous Substances Information system (HSIS). Accessed January 2015 at http://hsis.safeworkaustralia.gov.au/HazardousSubstance.

UNEP (2013), Persistent Organic Pollutants Review Committee Working group on guidance on alternatives to perfluorooctane sulfonic acid, its salts, perfluorooctane sulfonyl fluoride and their related chemicals. Guidance on alternatives to perfluorooctane sulfonic acid, its salts, perfluorooctane sulfonyl fluoride and their related chemicals Second revised draft 26 April 2013. Accessed January 2015 at http://chm.pops.int/Convention/POPsReviewCommittee/LatestMeeting/POPRC8/POPRC8Followup/tabid/2911/Default.aspx

Last Update 13 February 2015