In this study, we examined the effect of polychlorinated biphenyls (PCBs) in the presence of natural and synthetic terpenes and biphenyl on biomass production, lipid accumulation, and membrane adaptation mechanisms of two PCB-degrading bacterial strains Pseudomonas stutzeri and Burkholderia xenovorans LB400. According to the results obtained, it could be concluded that natural terpenes, mainly those contained in ivy leaves and pine needles, decreased adaptation responses induced by PCBs in these strains. The adaptation processes under investigation included growth inhibition, lipid accumulation, composition of fatty acids, cis/trans isomerization, and membrane saturation. Growth inhibition effect decreased upon addition of these natural compounds to the medium. The amount of unsaturated fatty acids that can lead to elevated membrane fluidity increased in both strains after the addition of the two natural terpene sources. The cells adaptation changes were more prominent in the presence of carvone, limonene, and biphenyl than in the presence of natural terpenes, as indicated by growth inhibition, lipid accumulation, and cis/trans isomerization. Addition of biphenyl and carvone simultaneously with PCBs increased the trans/cis ratio of fatty acids in membrane fractions probably as a result of fluidizing effects of PCBs. This stimulation is more pronounced in the presence of PCBs as a sole carbon source. This suggests that PCBs alone have a stronger effect on bacterial membrane adaptation mechanisms than when added together with biphenyl or natural or synthetic terpenes.

Feasibility of ozone oxidation for the elimination of selected dissolved organic micropollutants from water and wastewaters was studied. Five organochlorine pesticides, i.e. hexachlorobutadiene, pentachlorobenzene, hexachlorobenzene, lindane, and heptachlor, were used as organic contaminants of model water. The first four of them are classified as priority hazardous substances. The oxidation treatment process was performed in a jet loop reactor. Ozone was prepared from pure oxygen. Quantification of the organochlorine pesticides in water was achieved by the gas chromatographic method after liquid-liquid extraction. Significant contribution of stripping to the removal of the investigated compounds during the ozonation treatment was also proven by the results. Effective ozonation time with regard to treatment efficiencies was 30 min, which corresponds to the ozone input of 317 mg per liter of active volume of the ozonation reactor. Single power law kinetic models were used to describe experimental data and kinetic parameters were estimated. The best fit of the experimental degradation data of all studied pollutants was obtained by the second order kinetic model. It can be concluded, based on the results obtained, that the applied ozonation process is a promising procedure for the removal of the investigated pesticides from aquatic environment.

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