Dietary cadmium intake from rice and vegetables and potential health risk: A case study in Xiangtan, southern China

Abstract

Soil contamination in some areas of southern China has resulted in elevated dietary intake of cadmium (Cd), posing a potential risk to human health. A survey of paired soil-rice (n = 200) and soil-vegetable (n = 142) samples was conducted in Xiangtan county of Hunan province, southern China. The concentrations of Cd in all the samples were determined by inductively coupled plasma mass spectrometry. Dietary intakes of Cd from the consumption of locally produced rice and vegetables were estimated for different age groups. Among the 342 crop samples collected in the survey, 88% and 29% of rice grain and vegetable samples, respectively, exceeded the Chinese maximum permissible limit for Cd (0.2 mg dry weight kg^-1, 0.2 mg fresh weight kg^-1 and 0.1 mg fresh weight kg^-1 for rice, leafy vegetables and for rootstalk and legume vegetables, respectively). The median dietary Cd intake varied from 66.5 to 116 μg Cd kg^-1 body weight (BW) month^-1, with children (4-11 years) exhibiting the highest intake. These values are 2.7-4.6 times the tolerable dietary intake of 25 μg kg^-1 BW month^-1 recommended by the Joint FAO/WHO Expert Committee on Food Additives. For the general population in Xiangtan county, rice contributed the majority (81%) of the Cd intake with vegetables contributing only 19%. The median hazard quotient calculated from dietary Cd intake was 2.4 times the permissible level, indicating a high risk to the local residents. This study highlights an urgent need to reduce the transfer of Cd from soil to the food chain in the investigated region.

Keywords: Cadmium (Cd); Dietary intake; Rice; Soil; Vegetable.