Assessing the toxic potency of absorbed trihalomethanes in leafy vegetables: the effects of different Chlorine pretreatment

Abstract

Trihalomethanes (THMs) are a class of compounds formed when organic substances in water interact with halogen disinfectants such as chlorine. The specific THMs include CHBr₃, CHClBr₂, CHCl₂Br, and CHCl₃. THMs are toxic disinfection by-products (DBPs) that pose potential risks to human health and can be present in ready-to-eat vegetables. Our study examined key variables such as contact time, chlorine concentration, and vegetable type on the formation and absorption of these contaminants. Laboratory simulations involved 22 samples characterized by differing chlorine concentrations, contact durations, and three vegetable types: celery, lettuce, and leek. The result showed that the maximum concentration of THMs (354.73 µg L^− 1) in celery was observed when 300 mg L-1 of chlorine for 15 min was employed. The results demonstrated that contact time significantly affected the formation and absorption of THMs. Celery demonstrates a greater absorption of THMs than others. The evaluation of lifetime cancer risk (LTCR) and hazard index (HI) for THMs across 22 simulated test conditions indicated that CHClBr₂ exhibited the highest LTCR at 7.34 × 10^⁻⁶. Also, the average influence of LTCR for CHBr₂Cl constituted 64%, CHBr₃ accounted for 21%, CHBrCl₂ represented 10%, and CHCl₃ was 5%. The results showed that CHBr₃ had the most effect on the hazard index, while CHCl₃ showed the lowest impact. These findings assist food industry professionals in reducing THM absorption by regulating chlorine concentration and contact time during vegetable disinfection.

Graphical Abstract