Pyrrolizidine Alkaloids in Tea ( Camellia sinensis L.) from Weeds through Weed-Soil-Tea Transfer and Risk Assessment of Tea Intake.

Pyrrolizidine alkaloids (PAs) have been detected in tea and can threaten human health. However, the specific source of PAs in tea is still unclear. Here, 88 dried tea products collected from six major tea-producing areas in Anhui Province, China, were analyzed. The detection frequency was 76%. The content of total PAs in dried tea was between 1.1 and 90.5 μg/kg, which was all below the MRL recommended by the European Union (150 μg/kg). In the Shexian tea garden, PAs in the weeds and weed rhizospheric soil around tea plants and the fresh tea leaves were analyzed. Intermedine (Im), intermedine- N -oxide (ImNO), and jacobine- N -oxide (JbNO) were transferred through the weed-to-soil-to-tea route into the fresh tea leaves; only Im and ImNO were detected in dried tea samples. Potential risk of the total PAs in the tea infusion was assessed according to the margin of exposure method, and it might be a low concern for public health.