Dissipation and dietary risk assessment of tristyrylphenol ethoxylate homologues in cucumber after field application

Dissipation and potential risk of tristyrylphenol ethoxylate homologs in peanuts by spraying and root irrigation: A comparative assessment

Peanuts, known for their nutritional value, health benefits, and delicious taste, are susceptible to agricultural chemical contamination, posing a challenge to the peanut industry in China. While tristyrylphenol ethoxylates (TSPEOs) have garnered attention for their widespread use in pesticide formulations, their dissipation and potential risks in peanuts remain a gap in knowledge. This study, unique in its focus on TSPEOs, investigates their dissipation and potential risks under two common application modes: spraying and root irrigation. The concentration of total TSPEOs in peanut plants was significantly higher when sprayed (435-37,693 μg/kg) than in root irrigation (24-1602 μg/kg). The dissipation of TSPEOs was faster in peanuts and soil when sprayed, with half-lives of 3.67-5.59 d (mean: 4.37 d) and 5.41-7.07 d (mean: 5.95 d), respectively. The residue of TSPEOs in peanut shells and soil were higher with root irrigation (8.9-65.2 and 25.4-305.1 μg/kg, respectively) than with spraying (5.4-30.6 and 8.8-146.5 μg/kg, respectively). These results indicated that the dissipation behavior of TSPEOs in peanuts was influenced by application modes. While the healthy and ecological risk assessments of TSPEOs in soil and peanut shells showed no risks, root irrigation might pose a higher potential risk than spraying. This research provides valuable data for the judicious application of pesticides during peanut cultivation to enhance pesticide utilization and reduce potential risks.

Occurrence and distribution of trisiloxane ethoxylates in citrus orchard soils in China: Analytical challenges

Trisiloxane ethoxylates (TSEOn) are widely used as agricultural surfactants due to their significant synergism with the active ingredients of pesticides, generally, including three typical end groups which are hydroxyl (TSEOn-H), methoxy (TSEOn-CH3), and acetoxy (TSEOn-COCH3), respectively. However, the potential ecotoxicological and endocrine-disrupting risks of TSEOn congeners have recently attracted ever-growing concern. Above all, there is limited research on the concentration levels of TSEOn in agroecosystems. This study, simultaneous analysis of 39 TSEOn oligomers in citrus orchard soils in China was implemented by the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The method detection limits (MDLs) and the method quantification limits (MQLs) for TSEOn were 0.003-0.07 μg/kg and 0.01-0.20 μg/kg, respectively. The recoveries for TSEOn oligomers in soils ranged from 81 % ∼ 106 % with related standard deviations (RSDs) < 7 %. This newly developed UPLC-MS/MS method with high sensitivity and stability allows us to successfully trace the occurrence of TSEOn congeners in the citrus orchard soils from 3 provinces and 1 municipality in China. The detected concentrations of TSEOn-H oligomers in the sampled soils ranged from 0.02 to 0.288 μg/kg (dry weight). The congener profiles of TSEOn-H were dominated by TSEOn-H (n = 6- 8) in the soils. Additionally, the total concentrations of TSEOn-H congeners (ΣTSEOn-H) in the soils were in the range of 0.03 to 1.49 μg/kg. A comparison of ΣTSEOn-H distribution among the different citrus orchard soils indicated a higher level of ΣTSEOn-H in the soil samples collected from Zhejiang Province. Notably, TSEOn-CH3 or TSEOn-COCH3 oligomers were not detected in the tested soils. To the best of our knowledge, this is the first report on the occurrence and distribution of TSEOn congeners in agricultural soils.

Different dissipation potential and dietary risk assessment of tristyrylphenol ethoxylates in cowpea ecosystem in China

Tristyrylphenol ethoxylates (TSPEOn) are widely used as inert ingredients in pesticide formulations in the world. However, the information on the dissipation behavior of different homologs TSPEOn in agro-products is lacking. To investigate the dissipation behavior of TSPEOn, a cowpea field experiment treated with TSPEOn at different doses was carried out in Guangdong province, China. Different 24 TSPEO homologs were all detected in cowpea from the field terminal residue experiments, and the total concentrations of TSPEO homologs in cowpea were 40.0–1,374 μg/kg. The dissipation half-lives of 24 TSPEO homologs in soil were 1.51–2.35 times longer than those in cowpea. The long-chain homologs TSPEOn were dissipated faster than the short-chain homologs TSPEOn, suggesting a homolog-specific degradation of the TSPEOn in the cowpea ecosystem. The characteristic bimodal profiles of TSPEOn (n = 6–29) differing from that of the commercial TSPEOn were observed in the cowpea terminal residues experiment, indicating that the long-chain TSPEOn would degrade to short-chain TSPEOn in cowpea and soil. The acute and chronic dietary exposure risks of ΣTSPEOn in cowpea are within acceptable margins for human consumption across different ages and genders. But the health risks to children should be noticed in future.

Dissipation and risk assessment of forchlorfenuron and its major metabolites in oriental melon under greenhouse cultivation

Forchlorfenuron is a widely used plant growth regulator. The uptake of forchlorfenuron and its major metabolites poses a potential risk for human health. However, little is known about the dissipation of forchlorfenuron and its major metabolites in agricultural food. In this study, the metabolite 4-hydroxyphenyl-forchlorfenuron was first identified in oriental melon, which exhibited the highest level of residues of 4.42-5.12 μg/kg on the 4-7th days after application. Forchlorfenuron was found to be dissipated rapidly in melon at the recommended application rates, with half-lives ranging from 1.20 to 1.33 days. The rate of dissipation of 4-hydroxyphenyl-forchlorfenuron was greater than that of metabolism from forchlorfenuron in the oriental melon. However, the other metabolite, 3-hydroxyphenyl-forchlorfenuron, was not detected in oriental melon. The risk assessment showed that the acute and chronic dietary exposure risks of forchlorfenuron in oriental melon were 0.0011-0.0037% and 0.06-0.12%, respectively, suggesting little health risk to Chinese consumers.

Acute Toxicity and Ecotoxicological Risk Assessment of Three Volatile Pesticide Additives on the Earthworm-Eisenia fetida

Pesticide adjuvants (PAs) are important components of pesticide. Nonetheless, limited information is available regarding their toxic effects on biota in terrestrial ecosystem. In the present study, the mortality, growth inhibition ratio, and avoidance behavior of Eisenia fetida were examined to investigate the ecotoxicological effects of toluene, xylene, and trichloroethylene and further their mixture. The 24 h median lethal concentration (24 h-LC50) of the three PAs were 300.23, 1190.45, and 5332.36 mg/kg, and the 48 h-LC50 values were 221.62, 962.89, and 4522.41 mg/kg, respectively. The mixture exhibited significant synergistic effect on the E. fetida. There was significant growth inhibition on E. fetida by the tested PAs. The avoidance threshold values of E. fetida for the tested PAs were 1100 mg/kg, 250 mg/kg, 5000 mg/kg, and 25% of the mixture, respectively. The results evaluated the toxic effects of the three PAs and their mixture on E. fetida, provided a basis for ecotoxicological risk assessment of PAs in the soil ecosystem.

Pesticide Residue Behavior and Risk Assessment in Celery after Se Nanoparticles Application

This study investigates pesticide levels in celery, and compares their degradation, dissipation, distribution, and dietary risk after spraying with selenium (Se) nanoparticles. Abamectin, imidacloprid, acetamiprid, thiamethoxam, and lambda-cyhalothrin were sprayed at 1.6, 6.8, 2.0, 1.0, and 0.7 g a.i. ha⁻¹ followed by a 2 g·ha⁻¹ Se nanoparticle application during the growing period. Thiamethoxam, abamectin, imidacloprid, lambda-cyhalothrin, and acetamiprid in celery degraded following a first order kinetic model after 2 g·ha⁻¹ Se nanoparticles application. With the exception of acetamiprid, the half-lives of thiamethoxam, abamectin, imidacloprid, and lambda-cyhalothrin were reduced from 2.4, 0.5, 1.2, 4.2 days without Se nanoparticles application to 1.4, 0.2, 0.9, 3.7 days with the addition of Se nanoparticles (2 g·ha⁻¹), respectively. The chronic dietary exposure risk probability (RQc) and the acute dietary exposure risk probability (RQa) of celery after Se nanoparticles application were within acceptable limits for consumption except for abamectin.

Residue and dissipation of two formulations of emamectin benzoate in tender cowpea and old cowpea and a risk assessment of dietary intake

The dissipation and residue levels of emamectin benzoate emulsifiable concentrate (EC) and microemulsion (ME) formulations in tender cowpeas and old cowpeas were investigated under field conditions. The decline curves of emamectin benzoate residues in cowpea corresponded to first-order kinetics. The dissipation rate of emamectin benzoate in tender cowpeas was faster than that in old cowpeas. The half-lives of the EC were 1.34-1.39 d and 1.74-2.31 d in tender cowpea and old cowpea, respectively. For the ME, the half-lives were 1.39-1.51 d and 2.08-2.67 d, respectively. The risk of adult intake of emamectin benzoate from cowpea is within the acceptable limits of the human body. Compared to tender cowpeas, the risk of eating old cowpeas is higher. Emamectin benzoate (EC) is recommended for cowpeas when the intention is to harvest tender cowpeas, while both formulations are acceptable for cowpeas when the intention is to harvest old cowpeas.

Occurrences of eight common-used pesticide adjuvants in ten vegetable species and implications for dietary intake in North China

Pesticide adjuvants (PAs) are important components of pesticide products. However, limited information is available regarding their occurrences in foodstuffs. Herein, eight common-used PAs were investigated in vegetables in North China in 2014-2016. The residue levels of total PAs in vegetables from markets and farms were 500 and 661 μg/kg, respectively. The highest residues of total PAs were found in cauliflowers (average: 1.53 × 10³ μg/kg, market vegetables) and spinaches (average: 3.72 × 10³ μg/kg, farm vegetables), respectively. In addition, Tristyrylphenol ethoxylates (TPE) dominated the total 8 PAs concentrations in most vegetable species. Moreover, the risk assessment showed that the human health risks associated with TPE and nonylphenol (NP) exposure via vegetables for adults were acceptable, and the estimated daily intakes (EDIs) of other six PAs were in the range of <0.010-0.89 μg/kg bw/day, which were less likely to pose a threat to human health.