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6:2 Fluorotelomer sulfonate derivatives: Human health tier II assessment

01 July 2016

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Chemicals in this assessment

Chemical Name in the Inventory CAS Number
1-Propanaminium, N-(carboxymethyl)-N,N-dimethyl-3-[[(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)sulfonyl]amino]-, hydroxide, inner salt 34455-29-3
1-Propanaminium, N,N,N-trimethyl-3-[[(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)sulfonyl]amino]-, iodide 94088-80-9

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 closely related 6:2 fluorotelomer sulfonamide derivatives. In both cases, the sulfonamide is substituted with a 3-propyl amine group, which is further quaternised. In one chemical (CAS No 34455-29-3) the counterion is internal to the chemical (inner salt). The other (CAS No 94088-80-9) is a simple quaternary ammonium cation salt. The numbering in fluorotelomers refers to the number of fluorocarbons and hydrocarbons and in case of 6:2, it indicates six fluorinated carbons and two methylene carbons in the fluoroalkyl chain (Buck et al., 2011; Seow, 2013).

The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) has developed an action plan to assess and manage chemicals with a perfluorinated chain of four or more carbons which may degrade to perfluorinated carboxylic acids, perfluoroalkyl sulfonates and similar chemicals. This can be found in Appendix G of the Handbook for Notifiers on the NICNAS website (NICNASa).

In the environment, these chemicals are expected to biotransform into 6:2 fluorotelomer sulfonamides, which are further degraded to 6:2 fluorotelomer sulfonate (6:2 FTS) via a deamination reaction (Korzeniowski and Cortina, 2008; Moe et al., 2012; Zhang et al., 2016). Although they contain a sulfonate group, the FTS do not degrade or metabolise to form perfluorosulfonate chemicals such as perfluorooctanesulfonic acid (PFOS) or perfluorohexane sulfonate (PFHxS). It is indicated that the breakdown pathway is predominantly via initial hydrolysis to fluorotelomer alcohols (Zhang et al., 2016). In addition, the analysis of 6:2 FTS biotransformation using activated sludge demonstrated that the main degradation products of 6:2 FTSs were perfluorohexanoic acid (PFHxA) and perfluoropentanoic acid (PFPeA) (Wang et al, 2011). The degradation of 6:2 FTS into predominantly short-chain perfluorinated carboxylic acids (PFCAs) including PFHxA and PFPeA is also supported by other studies (Park et al., 2016; Zhang et al., 2016). For this reason, the assessed chemicals are assumed to be precursors for the short-chain PFCAs including PFHxA and PFPeA.

Human health assessments for simple, short-chain PFCAs and their salts (direct precursors) have been published earlier using the toxicity data available for PFHxA and perfluorobutanoic acid (PFBA), in order to compare their toxicity profile with that of perfluorooctanoic acid (PFOA) (NICNASb).

Risks from direct exposure to the chemicals and secondary exposure to degradation products have been considered.

Australian

No specific Australian use, import, or manufacturing information was identified for the chemicals in this group. Information collected by NICNAS in 2006 indicated PFHxA, PFPeA and their derivatives are not expected to be imported or manufactured in Australia.

It is noted that the chemicals in this group may be present in the environment due to release from pre-treated articles. However, release from this use is beyond the scope of this assessment.

International

The polyfluorinated betaine (CAS RN 34455-29-3) is reported to have use in fire-fighting foams (SFT, 2007; Buck, et al., 2011; Place & Field, 2012). It is marketed as fluorosurfactant Forafac 1157 (Moe et al., 2012). It is also used as an intermediate (Galleria Chemica)

Chemicals structurally related to CAS RN 94088-80-9 have been detected in fire-fighting foams and commercial surfactant concentrates (D’Agostino and Mabury, 2014; Place & Field, 2012).

Australian

No known restrictions have been identified.

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 for the chemicals.

International

No specific exposure standards are available for the chemicals.

No health hazard data are available for the chemicals in this group or the primary degradation product, 6:2 FTS. The bioaccumulation properties (Willson, 2007) and environmental toxicity profile of 6:2 FTS have been determined to be similar to those of PFHxA (Hoke et al., 2015). As the final degradation products of these chemicals are indicated to be short-chain PFCAs including PFHxA, the human health hazard assessment of these chemicals is based on the toxicity profile of short-chain PFCAs. The toxicological profile for short-chain PFCAs (C4–C6) suggests potentially better human health outcomes and less bioaccumulation than long-chain perfluoroalkyl substances (NICNASb).

When PFCAs and their indirect precursors were analysed in maternal and cord blood serum, 6:2 FTS was found to be the major component detected (Yang et al., 2016). This indicates that, while 6:2 FTS is not assumed to be bioaccumulative (Willson, 2007), the exposure to 6:2 FTS or its derivatives as assessed in this assessment may be significant. There was a lack of correlation between the maternal and cord serum 6:2 FTS indicating that maternal 6:2 (placental transfer) was not the only source for cord serum of 6:2 FTS. Other fluorotelomer surfactant precursors could, therefore, also be possible sources of 6:2 FTS in cord sera.

Critical Health Effects

The chemicals in this group have the potential to degrade to short-chain perfluorocarboxylic acids (PFCAs) containing 4–5 perfluorinated carbons. The data available indicate that the toxicological profile for short-chain PFCAs (C4–C6) gives rise to potentially better human health outcomes and the chemicals have lower bioaccumulation potential than long-chain perfluoroalkyl substances (NICNASb). Chronic low-level effects on human health have not been identified.

Public Risk Characterisation

Based on the available use information, the chemicals in this group are not likely to be available for consumer uses. Hence, the public risk from direct use of these chemicals is not considered to be unreasonable.

Secondary exposure to short-chain PFCAs in the environment

Public exposure to short-chain PFCAs could occur through secondary exposure in the environment. It is noted that the perfluorinated carboxylic acid degradants formed from the parent chemicals in this group may have multiple sources. These perfluorinated components are highly persistent and environmental levels can continue to increase over time due to indirect release pathways (NICNASc).  

The available data indicate that short-chain PFCAs have lower toxicity and are more rapidly eliminated than the long-chain perfluoroalkyl substances. Chronic low-level effects on human health have not been identified. The chemicals in the short-chain PFCA group are persistent in the environment, but have a short half-life in humans. Further assessment of the chemicals in this group may be necessary if information becomes available indicating adverse health effects from either the parent chemicals or their principal degradation products.

Occupational Risk Characterisation

Based on the available use information, the chemicals or their products are not manufactured in Australia. The chemicals are not likely to be used in significant quantities in Australia. Further assessment of the chemicals in this group may be necessary to inform the risk to workers if information becomes available indicating that these chemicals are introduced into Australia in significant quantities.

Long-term occupational exposure to very low concentrations of these chemicals and the degradation products could occur while using formulated products.

NICNAS Recommendation

The chemicals in this group have been assessed as having the potential to give rise to short-chain perfluorocarboxylic acids (PFCAs). Limited available toxicological data on these chemicals indicate a lower toxicity profile compared with long-chain PFCAs. However, should information become available indicating adverse health effects, further assessment of the chemicals in this group may be necessary to assess the risk of secondary exposure to short-chain PFCAs.

It is noted that the IMAP Human Health Tier II Assessment for Short-Chain Perfluorocarboxylic Acids (PFCAs) and their Direct Precursors (NICNASb) found that sufficient information was available to demonstrate that short-chain perfluorocarboxylic acids have a lower toxicity profile compared to PFOA, and it was recommended that the assessment be included in the action plan contained in Appendix G of the Handbook for Notifiers (NICNASa). This should be considered during the application of the action plan to any chemicals which may degrade to short-chain perfluorocarboxylic acids.

Advice for industry

Control measures to minimise the exposure to the chemicals should be implemented in accordance with the hierarchy of controls. Approaches to minimise the exposure include substitution, isolation and engineering controls. Measures required to eliminate or minimise exposure arising from storing, handling and using a hazardous chemical depend on the physical form and the manner in which the chemicals are used. Examples of control measures that could minimise the risk include, but are not limited to:

    • minimising manual processes and work tasks through automating processes;
    • work procedures that minimise splashes and spills;
    • regularly cleaning equipment and work areas; and
    • using protective equipment that is designed, constructed, and operated to ensure that the worker does not come into contact with the chemicals.

Guidance on managing risks from hazardous chemicals are provided in the Managing risks of hazardous chemicals in the workplace—Code of practice available on the Safe Work Australia website.

Personal protective equipment should not solely be relied upon to control risk and should only be used when all other reasonably practicable control measures do not eliminate or sufficiently minimise risk. Guidance in selecting personal protective equipment can be obtained from Australian, Australian/New Zealand or other approved standards.

Obligations under workplace health and safety legislation

Information in this report should be taken into account to help meet 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 chemicals 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 physical hazards of these chemicals has not been undertaken as part of this assessment.

References

D'Agostino LA, Mabury SA, 2014. Identification of novel fluorinated surfactants in aqueous film forming foams and commercial surfactant concentrates. Environ Sci Technol 48(1):121-129. doi: 10.1021/es403729e.

Galleria Chemica. Accessed April 2016 at http://jr.chemwatch.net/galleria/

Korzeniowksi S, Cortina T, 2008. Firefighting foams – Reebok redux. Accessed June 2016 at http://www.hemmingfire.com/news/fullstory.php/aid/118/Firefighting_foams__96_Reebok_redux.html

Moe MK, Huber S, Svenson J, Hagenaars A, Pabon M, Trümper M, Berger U, Knapen D, Herzke D, 2012. The structure of the fire fighting foam surfactant Forafac®1157 and its biological and photolytic transformation products. Chemosphere 89(7): 869-875. doi:0.1016/j.chemosphere.2012.05.012.

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 Chemical Notification and Assessment Scheme, NICNASc. Tier II environment assessment for Indirect Precursors to Short-Chain Perfluorocarboxylic Acids. Australian Government Department of Health. Available at http://www.nicnas.gov.au

National Industrial Chemicals Notification and Assessment Scheme, NICNASb. Tier II Human Health assessment for Short Chain Perfluorocarboxylic Acids and their Direct Precursors. Australian Government Department of Health. Available at www.nicnas.gov.au

Park S, Lee LS, Medina VF, Zull A, and Waisner S, 2016. Heat-activated persulfate oxidation of PFOA, 6:2 fluorotelomer sulfonate, and PFOS under conditions suitable for in-situ groundwater remediation. Chemosphere 145: 376-383. doi: 10.1016/j.chemosphere.2015.11.097.

Place BJ, Field JA, 2012. Identification of novel fluorochemicals in aqueous film-forming foams used by the US military. Environ Sci Technol 46(13):7120-7127. doi: 10.1021/es301465n.

Safe Work Australia (SWA). Hazardous Substances Information System (HSIS). Accessed March 2016 at http://hsis.safeworkaustralia.gov.au/HazardousSubstance

Seow J, 2013. Fire Fighting foams with Perfluorochemicals – Environmental Review. Accessed June 2016 at https://www.google.com.au/?gfe_rd=cr&ei=oi7dVPWCNaHu8wf144HoAw#safe=active&q=Fire+Fighting+foams+with+Perfluorochemicals+%E2%80%93+Environmental+Review

Statens forurensningstilsyn (SFT), 2007. PFOA in Norway. Norwegian Pollution Control Authority (Norwegian: Statens forurensningstilsyn), Oslo, Norway. Accessed June 2016 at http://www.miljodirektoratet.no/old/klif/publikasjoner/2354/ta2354.pdf

Wang N, Liu J, Buck RC, Korzeniowski SH, Wolstenholme BW, Folsom PW, Sulecki LM, 2011. 6:2 fluorotelomer sulfonate aerobic biotransformation in activated sludge of waste water treatment plants. Chemosphere 82(6):853-858. doi: 10.1016/j.chemosphere.2010.11.003.

Willson M, 2007. Fluorotelomer Based Foams: Are They Safe For Continued Use? Accessed June 2016 at http://www.joiff.com/documents/FluorotelomerbasedFoams.pdf

Yang L, Wang Z, Shi Y, Li J, Wang Y, Zhao Y, Wu Y, Cai Z, 2016. Human placental transfer of perfluoroalkyl acid precursors: Levels and profiles in paired maternal and cord serum. Chemosphere 144:1631-1638. doi: 10.1016/j.chemosphere.2015.10.063.

Zhang S, Lu X, Wang N, Buck RC, 2016. Biotransformation potential of 6:2 fluorotelomer sulfonate (6:2 FTSA) in aerobic and anaerobic sediment. Chemosphere 154: 224-230. doi: 10.1016/j.chemosphere.2016.03.062.

Last Update 01 July 2016