Detection And Evaluation Of Heavy Metal Content And Pesticide Residues Of Spring Tea In Changxing County

Our research is aimed to study and analyze the key factors of tea quality and safety in Changxingcounty by evaluating the heavy metal content in soil and tea leaves and pesticide residues of tea. Itwould be helpful to understand the tea garden soil, heavy metal in tea leaves, pesticide pollution, andtheir relationship in order to rationally plan tea gardens.The results showed that soil pH of tea gardens in Changxing county is4.3-6.2. Averageconcentration of Pb, Cr, Cd, Cu, Hg and As in soil is30.83mg/kg,49.85mg/kg,0.11mg/kg，23.07mg/kg,0.10mg/kg and9.12mg/kg, respectively. The single factor pollution index of soil islower than1，comprehensive pollution index is lower than0.7.The analysis demonstrated that theheavy metal composition of tea gardens in Changxing county are in the safe range，are in a cleanpollution-free level.Average concentration of Pb, Cr, Cd, Cu, Hg and As in tea leaves is1.084mg/kg,0.292mg/kg,0.025mg/kg,15.048mg/kg,0.101mg/kg and0.255mg/kg, respectively. The single factor pollutionindex of soil is lower than1，the comprehensive pollution index of tea is lower than0.6,the analysisdemonstrated all the heavy metal composition are in the safe range in the tea gardens in Changxingcounty; Products in line with A-level product standards, but individual regions productcomprehensive pollution index is higher, close to the secondary product standards, should causeenough attention.The analysis of soil heavy metals enrichment level in Changxing county shows that the Hgenrichment coefficient of tea in some area is higher. It mean that that Hg has a large number of existsin these areas of tea, which should arouse our great attention.This study was carried out on16kinds of pesticide residues. The bifenthrin is detected, and theothers were not detected.The pesticide detection rate was11.76%, and the residue does not exceed thelimits of small. The pesticides were used to the illegal tea production in Changxing county, which hasbeen effectively controlled.It show that the overall quality safety situation of tea is in a better level.The main components of tea is composed that: The tea is composed of44.32%aqueous extrac,4.00%amino acid,30.21%tea polyphenol, and8.27%coarse fiber. The phenol ammonia ratio was7.01~8.79.All the components of tea in Changxing county are better than the similar green tea in the otherarea.It showed that tea in Changxing county is in a good quality, which belong to the category of highquality green tea.In addition, there is a certain correlation between pH and heavy metals contents in soil, and tealeaves, pesticide residues of tea. This suggest relationship of some heavy metal composition and soilpollution, and are from the same source of pollution.