Dissipation and dietary exposure risk assessment of pyraclostrobin, fluxapyroxad, difenoconazole, and azoxystrobin in the Fritillaria field ecosystem

Contamination and health risk of pesticides in eight popular Chinese traditional medicines from Zhejiang Province

Zhejiang Province is one of the top five major provinces producing traditional Chinese medicines (TCMs) and is famous for Zhebawei (in Chinese), the eight popular geo-authentic TCMs including Rhizoma Atractylodis Macrocephalae, Radix Paeoniae Alba, Thunberg Fritillary Bulb, Chrysanthemum morifolium, Corydalis yanhusuo W. T. Wang, Scrophulariae Radix, Ophiopogonis Radix, and Curcuma Wenyujin Y. H. Chen et C. Ling. High proportion application and residue of pesticides directly affect the quality and yield of TCMs. In this study, pesticides residual levels in crude and processing samples were assessed along with their health risks in Zhebawei primarily produced in Zhejiang Province. In total, the exceeded ratios of pesticides residual concentrations in above mentioned eight species were 15/23, 4/7, 26/70, 22/44, 10/19, 8/12, 7/15, and 0/2, respectively. No acute dietary intake health risks were found but the long-term risks from permethrin in S. Radix should be carefully considered, with all quotient values being higher than 2.1 for all groups between 7 and 70 years. Furthermore, the risks of total benzene hexachloride in T. Fritillary Bulb and carbendazim in C. morifolium should be closely monitored. Suggestions for the cultivation and pesticide management of herbal medicines have been proposed to promote the quality of medicinal materials.

Dissipation, residue distribution, and risk assessment of ethiprole and its metabolites in rice under various open field conditions

BACKGROUND

Ethiprole has been registered to control planthoppers in rice fields for many years in Asia. However, its dissipation and residues in rice under natural field conditions and health hazards are largely unclear. In the present study, a modified QuEChERS (i.e. Quick Easy Cheap Effective Rugged Safe) and high-performance liquid chromatography-tandem mass spectrometry method was established to detect ethiprole and its metabolites, ethiprole amide and ethiprole sulfone, in brown rice, rice husks, and rice straw. The field experiments were implemented in 12 representative provinces of China under Good Agricultural Practices aiming to investigate the fate and terminal residues of ethiprole and its metabolites in rice. Finally, the dietary risk of ethiprole was evaluated.

RESULTS

The average recoveries of these analytes in all matrices were 86.4-99.0% with a repeatability of 0.575-9.38%. The limits of quantification for each compound were 0.01 mg kg-1 . Dissipation of ethiprole followed the single first-order, first + first-order, and first-order multi-compartment kinetic models with a half-life of 2.68-8.99 days in rice husks. The dissipation half-life of ethiprole combining all metabolites was 5.20-16.2 days in rice husks. The terminal residues of ethiprole and its metabolites at preharvest intervals of 21 days were < 0.011, 0.25, and 0.20 mg kg-1 in brown rice, rice husks, and rice straw, respectively. Ethiprole amide was undetectable in all matrices, and the risk quotient of ethiprole was far less than 100%.

CONCLUSION

Ethiprole rapidly converted to ethiprole sulfone in rice, and ethiprole and ethiprole sulfone mainly remained in rice husks and straws. The dietary risk of ethiprole was acceptable for Chinese consumers. © 2023 Society of Chemical Industry.

Dissipation, metabolism, accumulation, processing and risk assessment of fluxapyroxad in cucumber and cowpea vegetables from field to table

Understanding the residue fate of fluxapyroxad is critical for food safety and human health. The present study profiled the dissipation, metabolism, accumulation, removal and risk assessment of fluxapyroxad in cucumbers and cowpeas from field to table. Greenhouse-field trials suggested that fluxapyroxad dissipated faster in cucumbers than in cowpeas, and M700F008 was the only detected metabolite at <LOQ-37.92 μg/kg. Fluxapyroxad accumulated in cucumbers (average residue accumulation value, 1: 2.21: 1.16) and cowpeas (1: 1.33: 1.05) after repeated spraying. Peeling, washing and parboiling could remove fluxapyroxad from cucumbers and cowpeas (PF range, 0.16-0.85); however, fluxapyroxad was partly concentrated by stir-frying (PF range, 0.36-1.41). Moreover, fluxapyroxad residues increased with increasing pickling time. Chronic and acute risk assessments revealed that dietary exposure to fluxapyroxad was within the acceptable levels from cucumber and cowpea consumption. Given high residue levels and their potential accumulation, fluxapyroxad should be continuously monitored and assessed in the future.

Exploring China stepping into the dawn of chemical pesticide-free agriculture in 2050

China has implemented a series of policies to reduce the usage of chemical pesticides to maintain food production safety and to reduce water and soil pollution. However, there is still a huge gap in developing biological pesticides to replace chemical agents or managing pests to prevent crop production loss. It is necessary to predict the future use of chemical pesticides and to exploit the potential ways to control pests and crop diseases. Pesticide usage is affected by seasonal changes and analyzed by using a seasonal autoregressive integrated moving average (ARIMA) model (a statistical model that predicts future trends using time-series data). The future development of biopesticides in China was predicted using the compound annual growth rate (CAGR), which is calculated via the equation [(Final value/Starting value)1/years - 1] according to the annual growth rate of target products over time. According to the reducing trend of pesticide and biological pesticide usage annually, China is predicted possibly step into the era of pesticide-free agriculture in 2050 based on the analysis of the ARIMA model. With CAGR calculation, China will produce from 500 thousand to one million tons of biopesticides in 2050, which can meet the need to replace chemical pesticides in agriculture to prevent the present crop production loss. To achieve the goal, China still has the greatest challenges to develop biopesticides and use various strategies to control pest and crop diseases. China may step into the dawn of chemical pesticide-free agriculture in 2050 if biopesticides can be developed smoothly and pests can be controlled well using various strategies.

Dissipation Residue Behaviors and Dietary Risk Assessment of Boscalid and Pyraclostrobin in Watermelon by HPLC-MS/MS

Fungicides containing active ingredients of boscalid and pyraclostrobin have been widely applied in watermelon disease control. To provide data for avoiding health hazards caused by fungicides, we investigated its terminal residues and evaluated the dietary risk. In this work, watermelon samples were collected from field sites in six provinces and analyzed with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The average recoveries of boscalid and pyraclostrobin in the watermelon matrix were 97–108% and 93–103%, respectively, with the relative standard deviations (RSDs) ≤ 9.1%. The limits of quantifications (LOQs) were 0.01 and 0.005 mg/kg for boscalid and pyraclostrobin. Twenty-one days after applying the test pesticide with 270 g a.i./ha, the terminal residues of boscalid and pyraclostrobin were all below 0.05 mg/kg and below the maximum residue limits (MRLs) recommended by European Food Safety Authority (EFSA). According to the national estimated daily intake (NEDI), the risk quotients (RQs) of boscalid and pyraclostrobin were 48.4% and 62.6%, respectively. That indicated the pesticide evaluated in watermelon exhibited a low dietary risk to consumers. All data provide a reference for the MRL establishment of boscalid in watermelon for China.