Occurrence and exposure evaluation of perchlorate in indoor dust and diverse food from Chengdu, China.

A total of 688 samples, including 520 food samples belonging to 29 food types in 10 groups, 63 drinking water, and 105 indoor dust samples were collected during May to November in 2014 in Chengdu and Tianjin (only dust samples in Tianjin), China to investigate the perchlorate levels in these samples and to estimate the related exposure to Chinese people. Significant difference in indoor dust perchlorate levels was found between Chengdu and Tianjin, with the concentrations ranging from 0.11 to 38.8 mg/kg in Chengdu, and from 0.72 to 119 mg/kg in Tianjin. The mean perchlorate levels in 10 groups of food samples were in the order of vegetables>wheaten flour≈egg, and wheaten flour>milk>sea food>livestock meats≈poultry≈freshwater fish>fruits>steamed rice, while no statistical difference in perchlorate levels was found between egg and milk. Exposure evaluation indicated that indoor dust contributed little (less than 5%) to the total daily perchlorate intake, and food consumption was the primary perchlorate exposure route for Chengdu people, followed by drinking water. Based on the median perchlorate levels obtained in this study, the daily perchlorate intake was below the reference does suggested by the US EPA.