Priority perfluoroalkyl substances in surface waters - A snapshot survey from 22 developing countries.

The Stockholm Convention on Persistent Organic Pollutants (POPs) has established a global monitoring plan (GMP) to generate comparable data on the presence of POPs listed in the Stockholm Convention to identify changes in POPs concentrations over time and in regions. Perfluoroalkyl substances (PFAS) have been listed into the annexes of the Stockholm Convention in 2009 and 2019, namely perfluorooctane sulfonic acid (PFOS), its salts and perfluorooctane sulfonyl fluoride and perfluorooctanoic acid (PFOA), its salts and PFOA-related compounds. Perfluorohexane sulfonic acid (PFHxS) is recommended for listing in 2021. Surface water samples from 22 countries through the UNEP/Global Monitoring Plan 2 projects were collected from 2017 until 2019. 144 water samples from Africa (n=44), Asia-Pacific (n=60), and the Group of Latin America and Caribbean countries (GRULAC) (n=40) were analyzed using a ultra-performance liquid chromatograph coupled to a tandem mass spectrometer (UPLC-MS/MS). The three PFAS were quantified in the range of 0.03 ng L-1 to 6.23 ng L-1 for ΣPFOS, 0.05 ng L-1 to 4.02 ng L-1 for PFOA and 0.03 ng L-1 to 3.51 ng L-1 for PFHxS. Variation between or within regions, time points, countries' economy and population density was assessed. Statistically significant difference was found only for the PFOA concentration in the Asia Pacific region (11 countries) in comparison to Africa (seven countries) and GRULAC (five countries). Using the standardized sampling protocol for surface waters, these data may serve as a baseline for future monitoring activities and the starting point for trend assessment.