US EPA

3874973 

Technical Report 

Environment tier II assessment for perfluoroheptanoic acid (PFHpA) and its direct precursors 

National Industrial Chemicals Notification and Assessment Scheme :: NICNAS 

2017 

National Industrial Chemicals Notification and Assessment Scheme 

Sydney, Australia 

16 

English 

https://www.nicnas.gov.au/chemical-information/imap-assessments/imap-assessments/tier-ii-environment-assessments/perfluoroheptanoic-acid-pfhpa-and-its-direct-precursors
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has other version or edition 5024578 Perfluoroheptanoic acid (PFHpA) and its direct precursors: Environment tier II assessment

This Tier II assessment considers the environmental risks associated with the industrial uses of perfluoroheptanoic acid and its ammonium salt:

Heptanoic acid, tridecafluoro- (PFHpA)
Heptanoic acid, tridecafluoro-, ammonium salt (ammonium PFHpA)

The chemicals in this group contain chains of six perfluorinated carbons, terminated with a carboxylate group. They have been assessed in a group because both chemicals are expected to dissociate into the perfluoroheptanoate anion in the aquatic environment.

The two chemicals in this group have a perfluorinated carbon chain that is intermediate in length between the long-chain perfluorinated carboxylic acids (i.e. acids containing seven or more perfluorinated carbons) and the short-chain perfluorinated carboxylic acids (i.e. acids containing a chain of five, four or three perfluorinated carbons). The relative length of the carbon chain in perfluoroheptanoic acid is significant because the immediate long-chain homologue, perfluorooctanoic acid (PFOA), has been identified as persistent, bioaccumulative and toxic (PBT) according to domestic environmental hazard criteria. Chemicals with these hazard characteristics are of high concern to the environment and PFOA (and substances which may degrade to PFOA) are subject to increasingly stringent regulatory controls in other developed countries (NICNAS, 2015f).

However, the short-chain perfluorinated carboxylic acids (including the immediate short-chain homologue, perfluorohexanoic acid (PFHxA)) are not bioaccumulative and not toxic based on the available information, and they are considered to pose lower overall concerns for the environment than their long-chain homologues (NICNAS, 2015a). It is not currently clear whether the environmental hazards for the intermediate chain-length acids are comparable to the homologous long-chain or to the short-chain perfluorinated carboxylic acids in this series.

Under the NICNAS action plan for assessing and managing chemicals that could degrade to perfluorinated carboxylic acids, perfluoroalkyl sulfonates and similar chemicals, hazard information for PFOA is used to estimate the hazard of perfluorocarboxylic acid (PFCA) degradation products (with four or more perfluorinated carbons), unless sufficient toxicological data are available to demonstrate a lower toxicity profile. More information on the plan can be found in Appendix G of the NICNAS Handbook for Notifiers on the NICNAS website (NICNAS, 2015b).

This assessment will evaluate:

a) the properties of the chemicals in this group and compare them with short- and long-chain homologues; and

b) whether there are sufficient data to use in place of the default assumptions of the action plan.

The assessment of these chemicals as a group also provides additional relevant information for the risk assessment of other per- and poly-fluorinated substances containing a chain of at least six perfluorinated carbons that may degrade to PFHpA in the environment.