Abstract
The behaviour 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 carrot yield was significantly (P < 0.05) reduced 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 the 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. Non-significant (P < 0.05) PCB removal from vegetable-planted soils indicated that root vegetables were not able to enhance the autochthonous soil microorganisms to degrade PCBs by releasing exudates in the rhizosphere of vegetables. Bioaccumulation PCB factors derived from the cultivation of examined root vegetables in Chernozem and Fluvisol soils contaminated with PCBs at nearly 1500 µg/kg dw can be considered as low and negligible.