Determination of multiclass herbicides in sediments and aquatic products using QuECHERS combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and its application to risk assessment of rice-fish co-culture system in China

[Display omitted] • A method was developed to determine herbicides in sediments and aquatic products. • The method was used for the risk assessment of rice-fish co-culture system in China. • Human health risks of the herbicides were low in paddy field fish (HQ<0.002408). • Five herbicides in the sediment of paddy field showed high ecological risks (RQ>1.0). A sensitive method for determination of nine herbicides (prometryn, acetochlor, butachlor, quinclorac, bensulfuron methyl, metsulfuron methyl, atrazine, linuron and bentazone) in sediments and muscle of aquatic products was developed and validated using QuEChERS and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results demonstrated that the matrix-matched calibration curves for sediment and fish muscle were satisfactory linearly of a concentration (0.50 to 100 μg/L) (r > 0.999). The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.10 ~ 0.50 μg/kg and 0.50 ~ 1.50 μg/kg, respectively. The recoveries ranged from 82.94 to 114.41%, with the relative standard deviations (RSDs) lower than 13.11% for nine herbicides. Finally, the validated method was applied to detect nine herbicides in 68 rice-fish and 30 sediment samples in the rice-fish co-culture system (RFCS) in six provinces of China. The dietary and ecological risks were evaluated through a calculated hazard quotient (HQ) and risk quotient (RQ). The residues of herbicides in the paddy fish did not harm the human body (HQ < 0.002408). However, the ecological risks of herbicides in the RFCS could not be ignored. The seven herbicides were detected in the sediment of RFCS. They had ecological risks to the fish, daphnia and algae (RQ values ranged from 0.1666 to 28.4381). [ABSTRACT FROM AUTHOR]