Occurrence and exposure risk assessment of heavy metals and lanthanon in green tea samples cultivated in Hangzhou area

The concentration of heavy metals and lanthanon in 120 green tea samples grown in Hangzhou area were investigated by inductively coupled plasma mass spectrometry (ICP-MS). Except for Hg (69.2%), Sb (98.3%), Se (93.3%) and Sn (94.2%), the detection rate of the other 11 elements were all 100.0%. The mean concentration of heavy metals in tea showed the following order: Mn>Al> Ba> Cu> Ni> Cr> Pb> Sn> Li> V> Se> As> Cd> Sb>Hg. Mn was the highest element found in the tea samples with a concentration ranging from 202.00 to 2010.00 mg/kg and a mean of 836.00 mg/kg. The lowest element was Hg, with a concentration ranging from ND to 0.017 mg/kg and the mean concentration was 0.0033 mg/kg. And all the 120 samples did not exceed the standard limit value of heavy metal. The pollution level of heavy metals indicated that the single pollution index and comprehensive pollution index of green tea produced in Hangzhou area are far below 0.7, which belong to the clean and safety level. Health risk of inhabitant via consuming green tea was conducted and the HI value was 40.75%, less than 100%, which indicates that these chemicals pose no risk to human health in Hangzhou area.