Remediation of endosulfan-contaminated water by hairy roots: removal and phytometabolization assessment

Abstract

Although many countries banned the insecticide endosulfan, it is still an environmental pollutant. Plants metabolize the two diastereomers of the formulations known as technical grade endosulfan (TGE) by two phase I pathways: hydrolysis leading to less toxic derivatives and oxidation giving endosulfan sulfate which is as toxic as endosulfan itself. We assessed the removal, bioaccumulation and phase I metabolization of TGE from water matrices using hairy root clones (HRs) of three edible species, Brassica napus, Raphanus sativus and Capsicum annuum. B. napus and C. annuum HRs removed 86% of TGE from the bioreaction media in 2 and 96 h, respectively, whereas R. sativus HRs removed 91% of TGE within 6 h of biotreatment. In the experiments with B. napus, only endosulfan sulfate was detected in both biomass and medium, whereas R. sativus and C. annuum accumulated endosulfan sulfate and endosulfan alcohol. Besides, endosulfan lactone was detected in C. annuum reaction medium. Acute ichthyotoxicity assays toward Poecilia reticulata showed that media contaminated with TGE lethal levels did not produce mortality after the phytotreatments. This research highlights the feasibility of using HRs to evaluate plant enzymatic abilities toward xenobiotics and their potential for the design of ex situ decontamination processes.

Keywords:

• Acute fish toxicity
• Brassica napus L.
• Capsicum annuum
• phase I metabolism
• phytoremediation
• Raphanus sativus L

Acknowledgments

The authors thank Lic. Mónica Ferrari for technical assistance, Dr. Elizabeth Agostini for providing the B. napus L. HR clone and Franca Giannini-Kurina for statistical analysis.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by grants from UNSL [PROICO 2-1820], CONICET [PIP 2015-090] and ANPCyT [PICT 2018-02916], C.M.N., A.A.O. and M.K.S are members of the Research Career of CONICET.