Monitoring and risk assessment of perchlorate in tea samples produced in China

Accumulation of potentially perchlorate in tea is a new concern for tea consumers. The information on perchlorate contamination in tea is highly limited. This study aimed to investigate the occurrence and accumulation of perchlorate in tea samples from China and to assess human exposure risks. A total of 288 tea samples collected from 16 provinces of China were tested, and nearly 94.8% of the samples were found to have detectable perchlorate contamination. Concentrations of perchlorate ranged from below LOQ to 1274.3 μg/kg, with a mean value of 294.6 μg/kg. Tea samples collected from Central China had the highest mean perchlorate concentration (403.4 µg/kg). The mean and median perchlorate levels in the dark and black samples were much higher than that of other types of tea samples. After brewing tea, the dissolution rates of perchlorate from the dried tea ranged from 58.9% to 89.2%. For the worst-case scenario, the estimated daily intakes (EDIs) of tea samples in 16 investigated provinces ranged from 25.9 to 157.8 ng/kg bw/day and 29.7-180.7 ng/kg bw/day for male and female respectively, indicating no significant health risks to local residents via tea consumption.