Bioconcentration and tissue distribution of long- and short-chain perfluoroalkyl substances in zebrafish (Daniorerio)

Perfluoroalkyl substances (PFASs) composed of a hydrophobic perfluoroalkyl chain and a hydrophilic functional group are a class of persistent global contaminants. Many studies reported that PFASs were detected and could be... [ view full abstract ]

Perfluoroalkyl substances (PFASs) composed of a hydrophobic perfluoroalkyl chain and a hydrophilic functional group are a class of persistent global contaminants. Many studies reported that PFASs were detected and could be accumulated in many aquatic organisms. Although the bioconcentration kinetics and factors of PFASs have been investigated by some researchers, limited information is available about PFAS bioconcentration kinetics in various tissues of fish, and especially the difference in PFAS bioconcentration between single and multiple PFAS exposures. In this work, adult female zebrafish (Daniorerio) were exposed to systems containing single (perfluorooctane sulfonate, PFOS) and 11 PFASs (C4-C12 carboxylate, C4 and C8 sulfonate) for 28 days, respectively, to study the bioconcentration of PFASs in various tissues of zebrafish. The results showed that the bioconcentration kinetics of long chain PFASs (C7-C12) was fitted for the first-order accumulation rate model in blood, gill, intestines and stomach (IS), and muscle, while the zero-order accumulation rate model in liver, gonad and brain. After 28-day exposure, the bioconcentration factor (BCF) values of PFASs in each tissue increased with carbon chain length, except for perfluorobutyl sulfonic acid and PFOS. The BCF values of all tested PFASs were greatest in the blood (1.4-19248 L/kg wet weight), followed by liver, gill, gonad, brain, IS and muscle. Compared with the multiple exposure system, the BCF values of PFOS in blood, gill, IS and muscle in single PFOS exposure system were higher while in liver, gonad and brain were lower. This may be due to the different bioconcentration mechanisms in various tissues.