Toxic mechanism of three azole fungicides and their mixture to green alga Chlorella pyrenoidosa

Currently, few studies have investigated the joint toxicity mechanism of azole fungicides at different exposure times and mixed at the relevant environmental concentrations. In this study, three common azole fungicides, namely, myclobutanil (MYC), propiconazole (PRO), and tebuconazole (TCZ), were us...

Full description

Saved in:
Bibliographic Details
Published in:Chemosphere (Oxford) 2021-01, Vol.262, p.127793-127793, Article 127793
Main Authors: Nong, Qiong-Yuan, Liu, Yong-An, Qin, Li-Tang, Liu, Min, Mo, Ling-Yun, Liang, Yan-Peng, Zeng, Hong-Hu
Format: Article
Language:English
Subjects:
Azole fungicide
Chlorella pyrenoidosa
Physiological indicator
Toxic mechanism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Currently, few studies have investigated the joint toxicity mechanism of azole fungicides at different exposure times and mixed at the relevant environmental concentrations. In this study, three common azole fungicides, namely, myclobutanil (MYC), propiconazole (PRO), and tebuconazole (TCZ), were used in studying the toxic mechanisms of a single substance and its ternary mixture exposed to ambient concentrations of Chlorella pyrenoidosa. Superoxide dismutase (SOD), catalase (CAT), chlorophyll a (Chla), and total protein (TP), were used as physiological indexes. Results showed that three azole fungicides and ternary mixture presented obvious time-dependent toxicities at high concentrations. MYC induced a hormetic effect on algal growth, whereas PRO and TCZ inhibit algal growth in the entire range of the tested concentrations. The toxicities of the three azole fungicides at 7 days followed the order PRO > TCZ > MYC. Three azole fungicides and their ternary mixture induced different levels of SOD and CAT activities in algae at high concentrations. The ternary mixture showed additive effects after 4 and 7 days exposure, but no effect was observed at actual environmental concentrations. The toxic mechanisms may be related to the continuous accumulation of reactive oxygen species, which not only affected protein structures and compositions but also damaged thylakoid membranes, hindered the synthesis of proteins and chlorophyll a, and eventually inhibited algal growth. These findings increase the understanding of the ecotoxicity of azole fungicides and use of azole fungicides in agricultural production. [Display omitted] •The toxic mechanisms can be explained by the levels of SOD and CAT activities.•The growth inhibition ratios of TP and Chla increase with the increasing chemical concentrations.•The ternary mixture showed additive effect at 4 and 7 days exposure.•The environmental concentration of ternary mixture had little effect on the four physiological indexes.
ISSN:0045-6535
1879-1298
DOI:10.1016/j.chemosphere.2020.127793