Resident dietary exposure of cadmium in Jiangsu province

OBJECTIVE To investigate the resident dietary cadmium exposure in Jiangsu province and assess its safety. METHODS Cadmium concentration of 229 food items under 12 food groups were obtained from the food surveillance program in Jiangsu province between 2001 and 2006. Food consumption data of 778 food items of 3938 residents who were classified into four age groups (< 7, 7-, 13-, 18-) were got from the Nutrition and Health Status Survey of the Jiangsu resident in 2002 by 24 h dietary recall on three consecutive days. Dietary cadmium exposures for the residents of different age groups were obtained by using both point estimation and simple distribution estimation through integrating the two datasets above. The safety of dietary cadmium exposure was assessed. RESULTS Point estimation showed that the average dietary cadmium intakes of different age groups ranged from 5.7 to 8.6 microg/kg, accounting for 567.1% - 857.1% of the provisional tolerable daily intake (PTDI, 1.0 microg/kg). Result of simple distribution method showed mean daily cadmium exposure of different age groups ranged from 0.2 to 0.4 microg/kg, accounting for 20% - 40% of PTDI. Mean weekly cadmium exposure ranged from 1.4 to 2.5 microg/kg, accounting for 20% - 35.7% of the provisional tolerable weekly intake (PTWI, 7.0 microg/kg). The mean daily dietary cadmium exposure for different groups were as follows: < 7, 0.4 microg/kg; 7-, 0.3 microg/kg; 13-, 0.2 microg/kg; 18-, 0.2 microg/kg. Differences of daily dietary cadmium exposures among groups were significant (F = 69.0, P < 0.05). The mean weekly dietary cadmium exposure for different groups were: < 7, 2.5 microg/kg; 7-, 2.0 microg/kg; 13-, 1.4 microg/kg; 18-, 1.4 microg/kg. Differences of weekly dietary cadmium exposures among groups were also significant (F = 41.6, P < 0.05). The P97.5 of daily cadmium exposure for < 7 and 7- were 1.4 and 1.2 microg/kg, respectively, both of which were higher than PTDI. The P99.0 of daily cadmium exposure for 13- and 18- were 1.3 and 1.1 microg/kg, respectively. The daily dietary exposure from cereals for different age groups were 21.5 - 253.4 microg/kg, occupying 42.2% - 47.8% of the total daily exposure. Vegetables were 8.0 - 119.4 microg/kg, occupying 14.6% - 20.1%. CONCLUSION The average level of dietary cadmium exposures for residents in Jiangsu province calculated by simple distribution estimation were much lower than that calculated by point estimation and were considered to be at no risk. P97.5 or P99.0 of daily or weekly dietary cadmium exposure of different age groups exceeded PTWI and PTDI. The main food types of dietary cadmium exposure were cereals and vegetables.