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Fate Characterization of Benzene Kresoxim‐Methyl (a Strobilurin Fungicide) in Different Aerobic Soils
Author(s) -
Zhao Jinhao,
Wang Likun,
Cheng Jingli,
Wang Wei,
Ye Qingfu
Publication year - 2017
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2016.08.0288
Subject(s) - strobilurin , chemistry , fungicide , loam , soil water , environmental chemistry , mineralization (soil science) , agronomy , organic chemistry , soil science , nitrogen , azoxystrobin , environmental science , biology
Benzene kresoxim‐methyl (BKM) is a promising broad‐spectrum strobilurin fungicide widely used to control fungal pathogens in crops. However, information on its environmental fate is limited. To broaden our understanding of this fungicide's kinetic fate in aerobic soils, we labeled BKM with 14 C on its benzoate ring and used ultralow‐level liquid scintillation counting coupled with high‐performance liquid chromatography analysis. Results show that degradation, mineralization, and bound residue (BR) formation of BKM was controlled by soil type and microbial community composition. Degradation of BKM followed first‐order dynamics, and the half‐lives ( T 1/2 ) were 51.7, 30.8, and 26.8 d for clay, loamy, and saline soils, respectively. After 100 d, about 0.13, 4.35, and 5.94% of the initial 14 C‐BKM was mineralized, and 14.43, 19.90, and 28.81% was formed as BRs in the clay, loamy, and saline soils, respectively. About 60 to 85% of the 14 C‐BKM residue in soil was extractable; of this fraction, 30 to 50% was composed of incomplete degradation intermediates. Up to 40% of extractable 14 C‐BKM in soil was readily available. Our results suggest that BKM and its incomplete intermediates had a relatively long persistence in soil, which may lead to exposure for nontarget organisms. Soil microbes may play a dominant role in controlling the fate of BKM in soil as sterilization sharply decreased its mineralization rate from 4.35 to 0.03%, increased T 1/2 from 30.8 to 85.6 d, and decreased the BR fraction from 19.90 to 3.25%. Core Ideas The fate of benzene kresoxim‐methyl (BKM) is characterized for the first time. This fungicide has low mineralization and moderate bound residue formation in soil. BKM persisted in soil, which may influence soil organisms. This fungicide shows leaching/long‐distance transportation potential in soil. Dissipation and distribution of BKM residue depends on soil type and soil microbes.