Translocation and dissipation of seven indicator polychlorinated biphenyls from contrast soils cultivated with different root vegetables

The behavior of 7 polychlorinated biphenyls (PCBs) in agricultural Chernozem and Fluvisol soils from the Czech Republic planted with radishes, onions, and carrots was studied. Only the total biomass yield of carrots was significantly reduced (P < 0.05) when compared to the control biomass yield. All tested PCBs, especially congener PCB 28, were able to accumulate in slightly higher amounts in the radish surface than in the onion one. The highest PCB content was observed in the surface layer of carrots, which could be related to the agrochemical properties of soil, vegetation period, and more intensive contact of carrot roots with PCBs in a bulk soil. The translocation factors of PCBs were lower than 1, indicating a poor ability for PCB uptake from soil. The highest relative PCB removal from soil was observed in acidic Fluvisol, accounting for 27.2%, with a maximum of 2% plant contribution to soil PCB dissipation. The low relative removal of PCBs by plants indicates that in vegetable-planted soil, the removal of PCBs could be due to autochthonous soil microorganisms in the rhizosphere of vegetables. The bioaccumulation factors for PCBs derived from the cultivation of examined root vegetables in Chernozem and Fluvisol soils contaminated with PCBs at nearly 1500 µg/kg dry weight can be considered low and negligible.