Investigation and analysis of the content of 7 elements in Kuding Tea in China from 2016 to 2017

ObjectiveTo investigate the content and distribution characteristics of 7 elements in Kuding Tea in Chinese market.MethodsThe Kuding Tea samples from 20 provinces and cities in China were collected from 2016—2017， and the contents of lead， cadmium， mercury， arsenic， aluminum， chromium and nickel were simultaneously determined by microwave digestion and inductively coupled plasma mass spectrometry. Seven elements were analyzed by Mann-Whitney U test and Kruskal-Wallis test， and the correlation was analyzed by Kendall correlation coefficient.ResultsThe content levels of 7 elements in the large-leaf Kuding Tea from high to low were aluminum， cadmium， nickel， total chromium， total arsenic， lead and total mercury. The content levels of 7 elements in small-leaf Kuding Tea from high to low were aluminum， nickel， lead， total chromium， total arsenic， cadmium and total mercury. The frequency distribution of cadmium， nickel， thousand and total arsenic in large-leaf Kuding Tea was higher than that in small-leaf Kuding Tea， the content of cadmium was about 26 times of that in small-leaf Kuding Tea， the frequency distribution of lead， mercury and total chromium in small-leaf Kuding Tea was higher than that in large-leaf Kuding Tea， and the content of lead was significantly higher than that in large-leaf Kuding Tea. There were regional differences in the content of 6 elements of the two alternative teas， and some elements were correlated.ConclusionThere are 7 elements pollution in both large-leaf Kuding Tea and small-leaf KudingTea， and their contents are different and correlated in different regions. There are significant differences in the enrichment ability of key elements such as aluminum， cadmium and lead between the two substitute teas， and their health risks need to be further studied.