Stereoselective bioaccumulation, transformation, and toxicity of triadimefon in Scenedesmus obliquus

Abstract

In this study the stereoselective bioaccumulation and transformation of triadimefon and the toxicity of triadimefon and its metabolite triadimenol to the green algae Scenedesmus obliquus were studied. In growth inhibition experiments, triadimenol was more toxic than triadimefon, and (1S,2R)-triadimenol, which has the largest fungicidal activity, presented the highest toxicity to the algae. In bioaccumulation experiments, triadimefon was rapidly taken up by algae cells, and the decrease in the concentration of triadimefon was accompanied by an increase in triadimenol. The transformation of S-(+)- triadimefon was faster than that of the R-(-)-enantiomer, resulting in four triadimenol stereoisomers at different forming rates: B2 (1S, 2S) > B1 (1R, 2R) > A2 (1S, 2R) > A1 (1R, 2S). Thus, it is necessary to explore the enantioselective toxicology and ecological fate of these chiral pesticides in an environmental risk assessment. Also, their metabolites should be paid specific attention to since they may pose higher ecological risks.

Degradation of triadimefon and residue levels of metabolite triadimenol: tracing rapeseed from harvesting and storage to household oil processing

“…On the other hand, triadimefon degraded completely and only its metabolite, triadimenol, was detected in rapeseed – not only in the recommended commercial dosage group but also in the threefold and fivefold higher dosage groups. As was previously reported, the transformation of triadimefon to its metabolite, triadimenol, had been predicted and had been proven in field trials . According to our previous research, the degradation half‐lives of triadimefon transferred from rape plants to apicultural products such as pollen, honey and royal jelly were about 0.7, 12.5, and 19.5 days respectively .…”

“…As was previously reported, the transformation of triadimefon to its metabolite, triadimenol, had been predicted and had been proven in field trials. 42,43 According to our previous research, the degradation half-lives of triadimefon transferred from rape plants to apicultural products such as pollen, honey and royal jelly were about 0.7, 12.5, and 19.5 days respectively. 8 The fact that only metabolite triadimenol was detected in rapeseed samples might therefore be related to the interval between spraying time and harvest time.…”

Triadimefon in Aquatic Environments: Occurrence, Fate, Toxicity and Risk

“…Thus, two chiral centers and four stereo-isomers can result [33,34]. They were 1R, 2R-(-)-Triadimenol (RR-TDN), 1R, 2S-(-)-Triadimenol (RS-TDN), 1S, 2R-(+)-Triadimenol (SR-TDN), and 1S, 2S-(+)-Triadimenol (SS-TDN) [35,36] (Fig. 1).…”

Enantioselective separation and dissipation of pydiflumetofen enantiomers in grape and soil by supercritical fluid chromatography–tandem mass spectrometry

“…The introduction and utilization of complex structures have increased the proportion of chiral pesticides [2]. Although the physical and chemical properties of pesticide enantiomers are similar, they exhibit variable biological activity, toxicity, metabolism, and environmental fate [3‐5]. In addition to increased use of pesticides, the irrational application of chiral pesticides without distinguishing between the inactive or low activity and active enantiomers is associated with potential risks to humans and the ecological environment [6].…”