Evaluation of sheep exposure to poly- and perfluoroalkyl substances through hair sample analysis.

Abstract

Introduction: Poly- and perfluoroalkyl substances (PFASs) are a numerous group of synthetic organic compounds used in various industries. They pollute the natural environment and negatively affect humans and animals. The aim of the present investigation was to assess the exposure of sheep bred in the Kyrgyz Republic to six selected PFASs.

Material and methods: Six selected PFASs were assessed in 50 sheep (39 females and 11 males) of Kyrgyz and Arashan breeds ranging in age from 1 to 8 years (mean 2.1 ± 1.1), recruited equally from the Alamedin and Sokuluk regions. The substances were five perfluoroalkyl carboxylic acids (perfluorobutanoic acid - PFBuA, perfluoropentanoic acid - PFPeA, perfluorohexanoic acid - PFHxA, perfluoroheptanoic acid - PFHpA and perfluorooctanoic acid - PFOA) and perfluorooctane sulphonic acid (PFOS), and were determined through the liquid chromatography-tandem mass spectrometry of hair samples.

Results: All the listed PFASs were found in the studied hair samples. The highest concentrations were noted for PFPeA and PFBuA. The concentration of PFPeA ranged from 0.99 ng/g to 27.90 ng/g (mean 5.55 ± 4.54 ng/g) and that of PFBuA from 0.95ng/g to 14.18 ng/g (mean 2.24 ± 2.34 ng/g). The mean concentration levels of other PFASs were as follows: 1.06 ± 0.78 ng/g for PFHxA, 1.02 ± 0.76 ng/g for PFHpA, 0.87 ± 0.68 ng/g for PFOA and below the method quantification limit for PFOS. Clear differences in PFASs levels were noted between the two regions.

Conclusion: Sheep are exposed to various PFASs, and sheep wool and items made of it may be the source of human exposure to these compounds. Hair samples may be used for biomonitoring of sheep exposure to PFASs.