Uptake Of Perfluorinated Compounds (PFC_s) By Wheat(Triticum Aestivum L.)

Perfluorinated compounds (PFCs) are potential persistent organic pollutants, which have caused global environmental pollution. Owing to their unique physicochemical properties and environmental persistence, more and more people have paid attention to them in recent years. In this work, the uptakes of PFCs (PFOS, PFOA, PFBA, PFHpA and PFDoA) by plant were studied, using wheat (Triticum aestivum L.) as the test plant.Firstly, the PFCs uptake by wheat seedlings as a function of exposure time was monitored using a continuous flow in which the solute concentration in water was kept constant. The results showed that the five PFCs uptakes by wheat seedlings increased with exposure time. Their root and shoot uptakes reached an apparent uptake plateau with a range of72-100h and among them, FPOS was taken up fastest with Qmaxi=989μg/kg; PFBA was taken up slowest with Qmaxi=496μg/kg; PFDoA was taken up largest with Qmaxi=118388μg/kg. The concentrations of PFOS, PFOA, PFHpA and PFDoA in roots were higher than those in shoots. Whereas the maximum uptake of PFBA was found in shoots. The saturated vapor pressure of PFBA is higher than others. PFBA may directly uptake by shoots in the air.Secondly, the influence of the plant uptake of PFCs by the environmental factors (contaminant concentrations, pH value, salinity and temperature) was studied.(1) Concentration effect on PFCs uptake in wheat seedlingsThe uptakes of PFCs measured in the plant compartments increased directly with increasing PFCs concentration in the solution (from0.1to100mg/L). The sequence of PFCs uptake in roots and shoots:PFDoA> PFOS> PFOA> PFHpA> PFBA and PFDoA> PFBA> PFHpA> PFOA> PFOS.(2) pH effect on PFCs uptake in wheat seedlingsWhen pH was equal to6and7, the maximum uptake of PFOS was found.The sequence PFCs uptake in roots and shoots:PFDoA> PFOA> PFOS> PFHpA> PFBA and PFDoA> PFBA> PFOA> PFOS> PFHpA.(3) Salty effect on PFCs uptake in wheat seedlingsWith the increasing of salinity, PFCs uptakes in wheat were growing. The linear relationships were found between this increase in salinity for PFCs and in both plant compartments with correlation coefficient, which were above0.85. The sequence PFCs uptake in roots and shoots:PFDoA> PFOS> PFHpA> PFOA> PFBA and PFDoA> PFoA> PFBA> PFHpA> PFOS.(4) Temperature effect on PFCs uptake in wheat seedlingsThe PFCs (PFOS, PFBA and PFDoA) concentrations in the plant compartments increased directly with temperature increasing from20to30℃. PFOA and PFHpA uptake is increasing from20to25℃, then decreasing slightly with temperature increasing from25℃to30℃. The sequence PFCs uptake in roots and shoots:PFDoA> PFHpA> PFBA> PFOA> PFOS and PFDoA> PFBA> PFHpA> PFOS> PFOA.