Enantioselective uptake, translocation and degradation of the chiral pesticides tebuconazole and imazalil by Phragmites australis. (October 2017)

• Record Type: Journal Article
• Authors: Lv, Tao; Carvalho, Pedro N.; Casas, Mònica Escolà; Bollmann, Ulla E.; Arias, Carlos A.; Brix, Hans; Bester, Kai
• Is Part Of: Environmental pollution. Volume 229(2017)
• Page Start: 362
• Page End: 370
• Publication Date: 2017-10
• Subjects: Constructed wetlands -- Contaminants of emerging concern -- Enantiomeric fraction -- Phytoremediation -- Transformation product; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2017.06.017
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Phytoremediation of realistic environmental concentrations (10 μg L −1 ) of the chiral pesticides tebuconazole and imazalil by Phragmites australis was investigated. This study focussed on removal dynamics, enantioselective mechanisms and transformation products (TPs) in both hydroponic growth solutions and plant tissues. For the first time, we documented uptake, translocation and metabolisation of these pesticides inside wetland plants, using enantioselective analysis. Tebuconazole and imazalil removal efficiencies from water reached 96.1% and 99.8%, respectively, by the end of the experiment (day 24). Removal from the solutions could be described by first-order removal kinetics with removal rate constants of 0.14 d −1 for tebuconazole and 0.31 d −1 for imazalil. Removal of the pesticides from the hydroponic solution, plant uptake, within plant translocation and degradation occurred simultaneously. Tebuconazole and imazalil concentrations inside Phragmites peaked at day 10 and 5d, respectively, and decreased thereafter. TPs of tebuconazole i.e., (5-(4-Chlorophenyl)-2, 2-dimethyl-3-(1H-1, 2, 4-triazol-1-ylmethyl)-1, 3-pentanediol and 5-(3-((1H-1, 2, 4-Triazol-1-yl)methyl)-3-hydroxy-4, 4-dimethylpentyl)-2-chlorophenol) were quantified in solution, while the imazalil TPs (α-(2, 4-Dichlorophenyl)-1H-imidazole-1-ethanol and 3-[1-(2, 4-Dichlorophenyl)-2-(1H-imidazol-1-yl)ethoxy]-1, 2-propanediol) were quantified in both solution and plant tissue. Pesticide uptake by Phragmites was positively correlated with evapotranspiration. Pesticide removal from the hydroponic solution was not enantioselective. However, tebuconazole was degraded enantioselectively both in the roots and shoots. Imazalil translocation and degradation inside Phragmites were also enantioselective: R -imazalil translocated faster than S -imazalil. Graphical abstract: Highlights: Enantioselective dynamics of azole pesticides in Phragmites were first time tested. Uptake, translocation and degradation of azoles in plants occurred simultaneously. Both pesticides were degraded in plants enantioselectively but not in solution. R -imazalil translocated faster than S -imazalil in Phragmites . Transformation products of both pesticides were present in solution and plant. Abstract : Tebuconazole and imazalil were different in removal dynamics, enantioselective mechanisms and transformation products during phytoremediation by Phragmites.