Perfluoroalkyl substances: a risk for the aquatic environment? A one-year case-study in river waters of Central Italy

Abstract Perfluoroalkyl substances (PFASs) are a large class of persistent emerging pollutants, ubiquitous in different environmental compartments. In this study, twenty-one PFASs were determined in seventy-eight water samples collected from six different rivers in Umbria region (central Italy) during thirteen-months monitoring campaign. The sum of the twenty-one target analytes (Σ21PFASs) ranged from 2.0 to 68.5 ng L− 1, with a mean value of 22.0 ng L− 1. The highest concentrations of Σ21PFASs were recorded in the warmest months (from June to September), due to a reduced river streamflow caused by low rainfall and high temperatures. PFASs with a number of carbon atoms between four and nine prevail over C10-C18 congeners, due to their higher water solubility and to their increased use in industry. PFBA followed by PFPeA, PFHxA and PFOA, were the most abundant congeners detected in the analyzed river water samples. Finally, the calculation of risk quotients (∑RQs) has allowed to assess the risk for three aquatic organisms (fish, algae and daphnid) deriving from the exposure to PFASs. The survey showed that the risk for the three aquatic organisms during the four seasons and throughout the year was always negligible. The only exception was a low risk for fish and daphnid in GEN river considering the annual exposure.