Can perfluoroalkyl acids biodegrade in the rumen simulation technique (RUSITEC)?

J Kowalczyk,S Riede,H Schafft,G Breves,M Lahrssen-Wiederholt

doi:10.1186/s12302-015-0063-4

Abstract

BackgroundThe behaviour of perfluoroalkyl acids (PFAAs) in tissues of ruminants has been shown to differ from that of monogastrics (J Agric Food Chem 61(12):2903–2912 doi:10.1021/jf304680j, 2013; J Agric Food Chem 62(28):6861–6870, 2014). This may be a consequence of the complex microbial ecosystem in the rumen. To evaluate this hypothesis, the recovery of PFAAs was studied using the rumen simulation technique as an indication for biodegradation in rumen. The PFAA-recovery from a microbial fermentation of feed containing PFAAs was compared to the same feed in the absence of ruminal microorganisms (MOs).ResultsRelease of PFAAs from feed into fermentation fluid was found to be faster for perfluorobutane sulfonic acid (PFBS) than for perfluorooctane sulfonic acid (PFOS). Differences between perfluoroalkyl carboxylic acids (PFCAs) could not be observed. Proportions of PFAAs recovered in the fermentation fluids decreased by increasing chain lengths for the perfluoroalkyl sulfonic acids (PFSAs) (31 % PFBS, 28 % perfluorohexane sulfonic acid [PFHxS], 20 % perfluoroheptane sulfonic acid [PFHpS], 11 % PFOS) and PFCAs (33 % perfluorohexane carboxylic acid [PFHxA], 32 % perfluoroheptane carboxylic acid [PFHpA], 24 % perfluorooctanoic acid [PFOA]). In contrast, levels in feed increased with increasing chain length for both PFSAs and PFCAs.ConclusionThe attachment of MOs to feed particles was assumed to account for higher PFAA levels in fermented feeds and for lower levels in the fermentation fluids. Total recovery of PFAAs was significantly lower in presence of ruminal MOs compared to experimental procedure under sterile conditions. Although, there are optimal reductive conditions for MOs in rumen, our results do not univocally indicate whether PFAAs were degraded by ruminal fermentation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12302-015-0063-4) contains supplementary material, which is available to authorized users.

Highlights

The behaviour of perfluoroalkyl acids (PFAAs) in tissues of ruminants has been shown to differ from that of monogastrics (J Agric Food Chem 61(12):2903–2912 doi:10.1021/jf304680j, 2013; J Agric Food Chem 62(28):6861–6870, 2014)
The attachment of MOs to feed particles was assumed to account for higher Perfluoroalkyl acids (PFAAs) levels in fermented feeds and for lower levels in the fermentation fluids
The results showed that perfluorobutane sulfonic acid (PFBS) and perfluorooctanoic acid (PFOA) had no tendency of accumulation in blood plasma of dairy cows compared to perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS), while the affinity for blood plasma were evenly high for all PFAAs in fattening pigs

Summary

Introduction

The behaviour of perfluoroalkyl acids (PFAAs) in tissues of ruminants has been shown to differ from that of monogastrics (J Agric Food Chem 61(12):2903–2912 doi:10.1021/jf304680j, 2013; J Agric Food Chem 62(28):6861–6870, 2014) This may be a consequence of the complex microbial ecosystem in the rumen. PFAS are used in numerous industrial applications (e.g. electroplating, fluoropolymer production, photography), fire extinguishing agents and as processing aids in impregnation agents for a large number of consumer products (e.g. textile, carpet and leather protectors and food contact papers) since the 1950s [4,5,6] Because of their various applications, large amounts of PFAS have been released into the environment, leading to their. In the European union, the phase-out of long-chain PFCAs (C9, C11–C14), PFOA and its ammonium salt (APFO) is controlled using the European chemical regulation (REACH EC No 1907/2006). PFOA is discussed for inclusion into the restriction proceedings regulated in REACH Annex XVII (Restriction, Art. 67) [21, 22]

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