Transfer and risk assessment of perchlorate during green/black tea processing and brewing.

Perchlorate was reported to be taken up by tea (Camellia sinensis L.) plants and mainly stored in leaves. However, the change of contents in perchlorate in fresh tea leaf-made tea and tea infusion remains unclear. Here, we revealed the transfer of perchlorate during green/black tea processing and brewing using UPLC-MS/MS and established a corresponding dietary risk assessment method. The processing factors based on the dry-weight contents of perchlorate during green and black tea processing were in the range of 0.96-1.17. The content of perchlorate was stable throughout tea processing. Perchlorate in made tea was prone to leaching into infusions with an average leaching rate of 74.1 ± 12.6 %. Moreover, risk assessment was developed based on the above processing factor, leaching rate and risk quotient (RQ) method, which contributes to estimating the impact of perchlorate in fresh tea leaves on human dietary exposure via tea drinking.