Acute toxicity, bioconcentration, and metabolomic profiling of agrochemical organosilicone spray adjuvants in Zebrafish

Agrochemical organosilicone spray adjuvants, widely applied in agroecosystems, are suspected to pose environmental risks based on recent studies. In response to these concerns, we have purified the active components of these adjuvants, specifically a series of oligomers of hydroxy(polyethyleneoxy) propyl-heptamethyl trisiloxane (TSS-H), including ethylene oxide (EO) units ranging from 4 to 12. For analysis of TSS-H in zebrafish and water, a method utilizing high-performance liquid chromatography coupled with high resolution mass spectrometry (HPLCHRMS) was developed. The findings revealed that at total TSS-H concentrations of 0.04, 0.4, and 4 mg/kg, the average recovery rate of TSS-H containing 4 to 12 EO units in zebrafish ranged from 81.2 % to 107.2 %, with relative standard deviations (RSDs) between 0.1 % and 8.4 %. The 96-hour LC₅₀ of TSS-H in zebrafish was 6.71±0.04 mg/L. At exposure concentrations of 0.0671 mg/L and 0.671 mg/L, TSS-H oligomers reached a steady state in zebrafish within 14–21 days, with concentrations ranging from 0.008 to 0.05 mg/kg and 0.018 to 0.348 mg/kg, respectively. Bioconcentration factor (BCF) values for TSS-H oligomers (4–12 EO units) were 1.87–11.59 at the low dose and 0.79–9.19 at the high dose after 14 days. The elimination half-lives of the oligomers were <2.37 days during the elimination phase. Non-targeted metabolomic analysis revealed both TSS-H doses significantly impacted lipid and amino acid metabolic pathways, with disruptions largely associated with abnormal energy metabolism, oxidative stress, and alterations in membrane composition. These findings are critical for assessing the food safety and environmental risks of agrochemical organosilicone spray adjuvants in fish.