Dissipation kinetics and leaching of cyazofamid fungicide in texturally different agricultural soils

Abstract

Dissipation and leaching studies of cyazofamid in two texturally different soils of Tarai region of India at two fortification levels (100 and 200 g a.i. ha -1 ) were carried out for monitoring residual toxicity and groundwater contamination. Soil was extracted with acetone : methanol (5:1 v/v) followed by cleanup with florisil SPE. Separation was achieved by RP-HPLC on a Discovery Ò C-18 column using mobile phase acetonitrile: water (60:40 v/v) and detection at 279 nm. Degradation pattern indicated correspondence to monophasic first-order kinetics in soils with half-life values ranging from 4.3 to 4.95 days. The degradation rate was slight different in both types of soils. Persistence was higher in sandy loam compared to silty clay loam soil. Linearity, R 2 of calibration curve, instrument limit of detection/quantitation (LOD/LOQ) was evaluated. Good linearity (R 2 = 0.99) of the calibration curves for quantification was obtained over the dynamic range of 0.1-10.0 lg mL -1 , and percent relative standard deviation was 1.72 %. Leaching experiment showed that cyazofamid could not leached beyond 15 cm of soil depth. Maximum concentration was at 5-10 and 10-15 cm soil depth. Average recoveries from soils fortified at 0.5-5.0 lg g -1 ranged from 78 to 86 %. Instrument LOD values were 0.01 lg mL -1 , and method LOQ values were 0.05 lg g -1 . A fast, easy and efficient method with acceptable performance was achieved. Results showed that cyazofamid has a short life in soils and low potential to leach down under heavy rainfall conditions. Results confirm that cyazofamid would not build up in the environment and have less possibility of groundwater contamination.

Residue behaviours, dissipation kinetics and dietary risk assessment of pyaclostrobin, cyazofamid and its metabolite in grape

“…Cyazofamid impairs ATP synthesis and thus is active for the control of late blight, downy mildew worldwide. For example, it disrupts the energy supply of blocking the electron transfer at the Qi (ubiquinone reducing site) centre of complex III of the enzyme cytochrome bc1 complex in mitochondria . Under aerobic conditions, 4‐chloro‐5‐ p ‐tolylimidazole‐2‐carbonitrile (CCIM) (CAS number 120118‐14‐1) is the main degradation product of cyazofamid in plants.…”

“…Previous studies have already shown that CCIM appears to be more acutely toxic than cyazofamid ( European Food Safety Authority 2016). LC as well as LC–MS have been used to analyse cyazofamid and CCIM. Dissipation of cyazofamid has been determined in tobacco and tomato .…”

Simultaneous determination of residues of metalaxyl, cyazofamid and a cyazofamid metabolite in tobacco leaves and soil by liquid chromatography with tandem mass spectrometry

“…Many studies have investigated residues of metalaxyl or cyazofamid in crops using high‐performance liquid chromatography (HPLC) (Lee et al, ; Malhat, ; Singh & Tandon, ; Tandon & Singh, ; Zheng, Feng, Ge, Lv, & Xie, ), ultra‐performance liquid chromatography (Liu et al, ), gas chromatography (GC) (Rani, V. K. Sharma, Rattan, Singh, & Sharma, ; Rattan & Sharma, ) and liquid chromatography with tandem mass spectrometry (LC‐MS/MS) (Lee et al, ; Li et al, ; Ramezani & Shahriari, ; Zhu et al, ). For example, Zheng et al () used a QuEChERS (quick, easy, cheap, effective, rugged and safe) HPLC method to detect trace amounts of metalaxy in watermelon, and the average recovery rates were between 92.20 and 98.90%.…”

Potential of some soil amendments in reducing leaching of fipronil to groundwater

“…Leaching is one of the major transportation processes responsible for groundwater contamination. In soil, it depends on the physicochemical properties of soil and water recharge rate and is predicted to be highest for shallow soils and for persistent compounds with low sorptivity (Singh and Tandon 2015). Fipronil has been found to be relatively mobile in soils.…”