Spatial distribution and partitioning behaviour of selected PFASs in surface water and sediment: a French nationwide survey
Résumé
The spatial distribution and partitioning of 22 selected poly- and perfluoroalkyl substances (PFASs) in 133 selected rivers and lakes was investigated at nationwide scale in mainland France. In view of the high number of data that fell below detection limits, statistical treatments taking into account left-censored data were implemented to compute descriptive statistics as well as correlations. On average, SPFASs amounted to 28 ng L-1 in the dissolved phase, and to 1.8 ng g-1 dw in the sediment. Although perfluorooctane sulfonate (PFOS) was found to be the prevalent compound on average in both compartments, considerable variations were observed between individual sampling stations, the most polluted stations exhibiting generally higher carboxylates (PFHxA, PFNA, PFTrDA) and 6:2 FTS levels. A Kohonen mapping was used as a preliminary step to identify similarities between stations as well as key correlations between PFASs compounds. Log Kd and log Koc partition coefficients were also determined, and the correlation with the perfluoroalkyl chain length was modeled. Organic carbon fraction or grain size appeared to be significant controlling factors of PFAS accumulation in the sediment.