Ecotoxicity of climbazole, a fungicide contained in antidandruff shampoo

Abstract

Emerging pollutants such as personal care products can reach the environment via effluents from wastewater treatment plants (WWTPs) and digested sludge. Only recently, the antidandruff agent and antimycotic climbazole was detected for the first time in a WWTP effluent with concentrations up to 0.5 µg/L. Climbazole acts as a C14-demethylase inhibitor (DMI) fungicide and thus has a high efficacy against fungi, but knowledge of its potential environmental impact is lacking. Therefore, the aim of the present study was to characterize climbazole's ecotoxicity by conducting standard biotests with organisms representing different trophic levels from the aquatic as well as the terrestrial ecosystems. It was found that the toxicity of climbazole is mostly similar to that of other DMI fungicides, whereas it proved to be particularly toxic to primary producers. The lowest median effective concentrations (EC50s) were determined for Lemna minor, at 0.013 mg/L (biomass yield), and Avena sativa, at 18.5 mg/kg soil dry weight (shoot biomass). Reduction of frond size in water lentils and shoot length in higher plants suggested an additional plant growth-retarding mode of action of climbazole. In addition, it was demonstrated here that for an ionizable compound such as climbazole, the soil pH can have a considerable influence on phytotoxicity.

Photodegradation of the azole fungicide climbazole by ultraviolet irradiation under different conditions: Kinetics, mechanism and toxicity evaluation

“…The predicted 96 h EC50 value of CZ (0.144 mg/L) for green algae was very close to the experimental 72 h EC50 values: 0.1536 mg/L for Navicula pelliculosa and 0.2144 mg/L for Pseudokirchneriella subcapitata (both taking biomass yield as endpoint) [14], which proved the relative accuracy of prediction, with great reference significance for evaluating the toxicity of CZ-BP1-CZ-BP5. As shown in Table S5, all the predicted EC50 values of CZ-BP1-CZ-BP5 for green algae were higher than that of CZ, which indicated that the CZ was more toxic than all its photodegradation by-products for green algae.…”

“…S6). These findings revealed that the toxicity of CZ to Lemna minor was reduced after the irradiation of UV-254, but Lemna minor was indeed an easily sensitive species to CZ [14]. During the process of photodegradation, the concentrations of CZ decreased continuously with the extension of irradiation time (the removal rate up to 97% at 110 min); while the estimated yields of its five by-products (CZ-BP1-CZ-BP5) increased slowly, but always lower than 6% (Fig.…”

“…It has been reported that Lemna minor is very sensitive to CZ with its EC50 (the concentration for 50% of maximal effect) of 0.0339 mg/L for the growth rate of frond number [14]. So Lemna minor was adopted to test the toxicity changes of the CZ photolysis system in present study.…”

“…for Text S1). According to the pKa value (7.50) of CZ, existing two species in aqueous solution [14], CZ + and CZ are the dominant species at pH = 5.0 and 9.0, respectively (Fig. S3).…”

“…Then through sewage effluent discharge and sludge application on land, the remaining CZ ended up in the receiving environments, including water compartment [8][9][10] and soil compartment [11,12] with an approximate distribution ratio of 93% in water and 7% in soil [13]. CZ has been reported to be quite toxic to aquatic and terrestrial organisms [12,14]. Moreover, azole fungicides like CZ have been regarded as potential endocrine disruptors due to their adverse effects on P450-regulated steroidogenesis [15,16].…”