Health risk assessment of toxic metals in commonly consumed salad leafy vegetables in Bangkok

Abstract

The objectives of this study were 1) to investigate concentrations of toxic metals including As, Cd, and Pb in the commonly consumed salad leafy vegetables which were sold in Bangkok, and 2) to assess potential human health risks of As, Cd, and Pb exposure via salad leafy vegetables consumption. A total of 120 samples were randomly collected from local fresh markets in Bangkok. The total concentrations of toxic metals were determined by an inductively coupled plasma mass spectroscopy (ICP-MS). Total concentrations of As, Cd and Pb in coral lettuce (CL), red coral (RC) and green oak (GO) for soil cultivation varied from 0.0207 to 0.2603 mg/kg, 0.0280 to 2.4862 mg/kg, and 0.0174 to 0.5314 mg/kg, respectively. For the hydroponic vegetables, total concentrations of As, Cd and Pb ranged from 0.0225 to 0.0943 mg/kg, 0.0223 to 0.4168 mg/kg, and 0.0095 to 0.3091 mg/kg, respectively. According to the health risk assessment, the HQ values of As, Cd, and Pb ranked in the following order: adults > adolescents > children. For soil cultivation, the average HQ values of As, Cd and Pb were 0.19 to 0.80, 0.24 to 2.29, and 0.04 to 0.14. Meanwhile, the average HQ values of As, Cd and Pb exposure from the hydroponically grown salad vegetables were 0.13 to 0.30, 0.11 to 0.38, and 0.02 to 0.08, respectively. According to the HQ values, Cd in RC consumption was higher than the acceptable non-cancer risk of 1 (HQ≥1). On the other hand, the GO and CL were safe for consumption as the HQ values for As and Pb were lower than 1 (HQ<1). As a consequence of the regular lettuce consumption, the adult population may develop non-cancer health risks (e.g., diabetes, kidney disease, and heart attack).