Residual level of dimethachlon in rice‐paddy field system and cooked rice determined by gas chromatography with electron capture detector

Abstract

In this study, a modified quick, easy, cheap, effective, rugged and safe method coupled with gas chromatography with electron capture detection was established to determine dimethachlon residues in paddy soil, rice husk, rice straw, brown rice and cooked rice. The limits of quantification of dimethachlon were 0.01 mg/kg for paddy soil, brown rice and cooked rice and 0.02 mg/kg for rice straw and rice husk. The mean recoveries were in the range 78.59-104.7% with relative standard deviation values of <10% for dimethachlon in the five matrices. For field experiments, the final residues of dimethachlon in paddy soil were < 0.05 mg/kg and were < 1.21 mg/kg in rice straw from six sites. The final residues of dimethachlon in the brown rice at 21, 28 and 35 days after spraying from six sites were 0.08-7.58 mg/kg, and 0.16-30.1 mg/kg in rice husk. Our six test sites covered the main rice-producing areas of China. The routine rice cooking process of a Chinese family could apparently increase the removal of dimethachlon in rice compared with brown rice, and the reduction ratios were > 96%.

Identification and Quantification of Dimethachlon Degradation Products in Soils and Their Effects on Soil Enzyme Activities

“…Many studies have reported on the analytical methods, residue levels, and rates of degradation of dimethachlon residues on some crops and soils. According to studies, dimethachlon has a half-life of 2.5–7.75 days on crops and 8.2–15.71 days on soils. − Dimethachlon poses an ecological risk; Zhang et al isolated and identified a novel dimethachlon-degrading strain Brevundimonas naejangsanensis J3 from the soils to accelerate its degradation. It was shown that soil microorganisms played an important role in the degradation of dimethachlon.…”

Maleic acid and malonic acid reduced the pathogenicity of Sclerotinia sclerotiorum by inhibiting mycelial growth, sclerotia formation and virulence factors

“…Utilizing chemical pesticides has long been an effective method for preventing and controlling S. sclerotiorum (Liu et al 2018(Liu et al , 2021Oliveira et al 2013a, b). However, the current issues of pesticide reduction and fungicide-resistant strains of S. sclerotiorum have received considerable attention (Sun et al 2018;Besil et al 2018;Zhou et al 2014a, b). Although numerous pieces of research focus on alternative methods like agricultural practice, biological methods and breeding disease-resistant cultivars (Alvarez et al 2012;Grandini et al 2022;Zhang et al 2020), these methods are not always available and effective.…”

Does solar light trap reduce the cost of pesticides used in rice field?

“…In Bangladesh, most of the farmer prefers chemical method for insect pest management. This irrational use of chemical pesticides in the rice ecosystem increases the cost of production and has a long-term residual impact on the environment and biodiversity (Yaqub et al, 2017;Sun et al, 2018;). Rice is cultivated around the haor area in Boro season, using chemical pesticides is so dangerous for the aquatic biodiversity of haor areas.…”