Critical knowledge gaps remain regarding the fate and effects of zwitterionic, cationic, and anionic perfluoroalkyl and polyfluoroalkyl substances (PFASs), including assessment of their bioaccumulation potential. Here, biota soil accumulation factors (BSAFs) were assessed in earthworms (Eisenia fetida) exposed to soil microcosms amended with zwitterionic fluorotelomers and anionic perfluoroalkyl acids. The 6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB) bioaccumulated in earthworms [BSAF ∼ 2.5−5.4 (g dw,worm /g dw,soil ) −1 ] but to a lesser extent than perfluorooctane sulfonate (PFOS: BSAF ∼ 21−29). The BSAF of perfluorocarboxylates increased from ∼2.0 for C 4 −C 6 analogues to ∼92 for perfluorotridecanoate (C 13 ). In earthworms exposed to Ansulite and Arctic Foam aqueous film-forming foams (AFFFs), the BSAF was related to perfluorinated chain length for n:3 fluorotelomer betaines (FtBs), n:1:2 FtB, and n:2 FTAB. Earthworms were also collected in situ from a fire-equipment testing site at a major Canadian airport. Summed PFAS concentrations were between 65 000 and 830 000 ng g −1 wet weight, possibly the highest burden recorded in terrestrial biota. Fluorotelomer sulfonates (6:2 FTS, 8:2 FTS, and 10:2 FTS) and FtB were particularly prevalent. Field worms also displayed elevated concentrations of n:3 acids (n = 3−11), but not those from laboratory microcosms exposed to fluorotelomer-based AFFFs. The findings provide an important confirmation to recent data suggesting that fluorotelomer compounds may accumulate in invertebrate species with limited metabolization.
While perceptual load has been proposed to reduce the processing of task-unrelated stimuli, theoretical arguments and empirical findings for other forms of task load are inconclusive. Here, we systematically investigated the detection and neural processing of auditory stimuli varying in stimulus intensity during a stimuli-unrelated visual working memory task alternating between low and high load. We found, depending on stimulus strength, decreased stimulus detection and reduced P3, but unaffected N1 amplitudes of the event-related potential to auditory stimuli under high as compared to low load. In contrast, load independent awareness effects were observed during both early (N1) and late (P3) time windows. Findings suggest a late neural effect of visual working memory load on auditory stimuli leading to lower probability of reported awareness of these stimuli.
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