Application of a comprehensive extraction technique for the determination of poly- and perfluoroalkyl substances (PFASs) in Great Lakes Region sediments.

A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to sediment cores from three small isolated lakes (Plastic Lake, Lake 442, Lake Tettegouche) and Lake Ontario in the Great Lakes Region. Recoveries of the target compounds using the optimized acetonitrile/sodium hydroxide extraction ranged from 73% to 120%. The greatest concentrations of per- and polyfluorinated alkyl substances (PFASs) were recorded in sediment from Lake Ontario (ΣPFASs 13.1 ng/g), where perfluorooctane sulfonic acid (PFOS) contributed over 80% of the total. Concentrations in Lake Ontario were approximately 1-2 orders of magnitude greater than the more remote lakes subject to primarily atmospheric inputs. Whilst the PFAS contribution in Lake Ontario was dominated by PFOS, the more remote lakes contained sediment with higher proportions of PFCAs. Trace amounts of emerging PFASs (diPAPs and PFPiAs) were found in very recent surface Lake Ontario and remote lake sediments

Formation of n-nitrosamines in drinking water sources: Case studies from Western Australia

This study investigated the formation of eight N-nitrosamines after laboratory chlorination and chloramination of Western Australian source waters (from protected catchments), which experience periodic cyanobacterial blooms. All measured N-nitrosamines, except N-nitrosodipropylamine, were detected at least once, and total N-nitrosamine formation was higher after chloramination than after chlorination. While previous studies have shown that some cyanobacteria can be related to the formation of N-nitrosamines, formation of N-nitrosamines in the waters tested did not correlate with total cyanobacteria count. Estimates of toxicity, using published 50% lifetime excess cancer risk values, indicated that N-nitrosodimethylamine (NDMA) was the highest contributor to the total measured N-nitrosamine toxicity, suggesting that other measuredN-nitrosamines will only influence toxicity when they arepresent at significantly higher concentrations than NDMA.When assessing the overall health impact of disinfectionby-products, it is important to also consider the formationof disinfection by-products other than N-nitrosamines,which may be present at higher concentrations and thus maypresent higher toxicity