Perfluorooctane sulfonate and perfluorooctanoic acid in the fingernails of urban and rural children

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two typical perfluorinated compounds (PFCs), found in a wide range of environmental media and organisms, including humans. Human biomonitoring studies of body fluids have revealed that in many areas of the world the general population has been exposed to background levels of PFOS and PFOA. Fingernail has been suggested as a promising biopsy material for assessment of PFCs environmental exposure. In the present study, PFOS and PFOA were quantified using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in fingernails of urban and rural children (N=93) aged 6–12 years. A questionnaire was conducted to determine factors that could influence the PFOS and PFOA levels in the children. The levels of PFOS in urban children were significantly higher (geometric mean (GM)=328 ng/g) than those in rural children (GM=27 ng/g). In contrast, PFOA levels were significantly lower in the urban children compared with the rural children. Significant positive correlation (R=0.53, P<0.05 for urban areas; R=0.71; P<0.001 for rural areas) between the PFOS and PFOA concentrations indicated they had similar sources. The PFOS and PFOA levels were higher in fingernail samples from children aged <9 years than in children aged ⩾9 years. In addition, females had higher PFOA levels than males, in both regions. Other factors that significantly influenced PFOS and PFOA levels were dietary habits and socio-economic background. The results of this study indicate fingernails are a suitable material for biomonitoring of PFCs environmental exposure. However, the levels determined in the fingernail samples need to be first evaluated with regard to the levels determined in other samples, such as human serum.