The Effect of Soil Properties on the Transformation of Climbazole and its Accumulation in Lettuce Plants

Milena Dulovic

Master's thesis

Abstract:

Climbazole is an antifungal agent and as it is used in personal care products, it is continuously entering the sewage system. Wastewater treatment plant (WWTP) processes are not optimized for its removal and, therefore, climbazole finds its way to the environment through WWTP effluents and sewage sludge. Climbazole’s toxic effect on organisms, especially aquatic ones, has been well documented in scientific literature. In this study, the effect of climbazole on lettuce plants (Lactuca sativa L., variety May King), soil microbial activity and its transformation and accumulation in soil and plant biomass was examined. The study is conceived as a pot experiment with three factors: concentration of climbazole, type of soil, and presence of plants. Three types of soil were used: soil that was treated long-term with farm-yard manure (FYM), soil treated long-term with mineral fertilizers (NPK) and control soil that wasn’t fertilized (CON). Climbazole was applied to the soils in concentrations: 0, 0.1, 1, 10, 100 and 1000 μg/kg of dry soil. The effect on plants was assessed through the germination rate of plant seeds and biomass yield, but no significant effects of climbazole in applied concentrations were recorded. The only concentration that had statistically positive effect on germination rate was 1 μg/kg in CON soil, which wasn’t replicated in other ones. The possible effect of climbazole on soil microorganisms was assessed through dehydrogenase activity, on which climbazole didn’t have a significant effect, except a positive one at 0.1 μg/kg concentration in NPK soil. However, significant stimulating effect of soil fertilization on germination rate, biomass yield and dehydrogenase activity were documented compared to the control. Both FYM and NPK soil affected germination rate and dehydrogenase activity, while FYM soil positively affected biomass yield. All plants wilted in NPK soil and about half of planned number in CON soil. The plants had symptoms of root rot, which indicates climbazole’s inability to control soil pathogens in applied concentrations. The highest removal of climbazole was recorded in FYM soil with plants – 83.03 % after 56 days of growth, while the lowest was in NPK soil with plants – 74.28 %. Detected transformation products of climbazole were: hydroxy-climbazole (oxidized form) and climbazole-alcohol found in two diastereomers (reduced form). Climbazole’s bioconcentration factor in lettuce’s roots was 2.91 and translocation factor was 0.08.

Keywords

Pharmaceuticals, Personal care products, Climbazole, Lettuce, Degradation, Accumulation

Language used: English

Date on which the thesis was submitted / produced: 25. 4. 2021

Thesis defence

• Supervisor: Ing. Filip Mercl, Ph.D.
• Reader: Petr Maršík, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / field:
Natural Resources and Environment / Natural Resources and Environment