The Pb And Cd Pollution Of Tea In The Northeastern Hunan Province Tea Gardens

In this investigation the polition of Pb and Cd to the northeast of Hunan province tea and tea garden soil, corresponding to the tea plant growth on the natural environment of tea samples. To provide a reference for the soil Pb and Cd monitoring, prevention and control of pollution, construction of organic tea garden, application of tea, Product development of tea. The results of this study are as follows:(1) All kinds of tea products in Hunan Province northeast of heavy metals lead and cadmium content analysisGreen Pb content 0.42～1.05mg/kg, Cd content of 0.0195～0.0234mg/kg; tea Pb content 0.73～1.23mg/kg, tea Cd content 0.0221～0.0379mg/kg; black tea Pb content 2.67～3.34mg/kg, Cd content of 0.0436～0.0576mg/L. Sample tea Pb, Cd detected values are lower, in line with the limits of the standard pollution-free tea, organic tea standards comply with the limits.(2)Analysis of heavy metals Pb and Cd contents of each soil in the northeast of Hunan ProvinceThrough the investigation on the northeast of Hunan Province eight soil content of lead and cadmium in. The content change of lead is 19.07mg/kg-42.39mg/kg interval, the average value is 26.72mg/kg, with two national soil environmental quality standard andpollution-free tea standard, and the content of Pb in soil were all reached the standards of organic tea garden. The content of cadmium in soil change interval 0.116mg/kg-0.318mg/kg, the average value is 0.183mg/kg, based on national standard GB15618-1995standard, in the northeast part of Hunan Province in the tea garden 72% belongs to clean,24% is still clean, only a mild case of excessive tea.(3) Analysis of different regions in Northeast of Hunan province in spring tea baihaozao heavy metal Pb, CdIn eight tea plantations in different regions in the northeast of Hunan Province, the earlyspring white tea ho parts (the heart of old leaves, shoots, stems) were investigated, and combined with the heavy metal content in soil, evaluation and analysis. The results of this study show that Pb and Cd elements in different region in spring baihaozao heart tip, oldleaves and stems significantly, the content of Pb in old leaves is about 4-10 times of the heart in the stem tip, the tip in the heart more than dozens of times; while the content of Cdin old leaves is about 3-6 times in the heart of the stem tip, is about 10-15 times of the heart in the shoot. Different tea garden tea in various parts of the content, the Pb contentof the tea shop um baihaozao stem and old leaves are respectively 20.05mg/kg,6.17mg/kg, Pb content of tea shoots Takahashi baihaozao up to 1.33mg/kg; Cd content of tea tea Takahashi is highest in stem 0.782mg/kg, Yang Linao baihaozao old leaves and the content of Cd in shoots of heart the highest 0.273mg/kg and 0.0652mg/kg respectively. Enrichment of tea tea in Pb, Cd, Pb, Cd in heart shoot content and soil pH showed a significant negative correlation, the correlation coefficients were:-0.983,-0.971.(4)Of different varieties of tea, the content of Cd Pb in Hunan province northeast of eachtea area in springAnd the enrichment coefficient of Pb content in different tea varieties are:heart tipbixiangzao 0.0383～0.0724mg/kg,0.0168～0.0204, Fuding white 0.0664 0.0768mg/kg,0.0179～0.0396, baihaozao 0.0256～0.0652mg/kg,0.0201～0.0579,0.0532 ～0.0638mg/kg, mulberry leaf with 0.0239～0.0429, Taoyuan Daye 0.0300 0.0732mg/kg,0.0123～0.215 and; enrichment coefficient of Cd content in different tea varieties are:heart tip bixiangzao 0.0383～0.0724mg/kg,0.30～0.43, Fuding white 0.0664～ 0.0768mg/kg,0.35～0.42, baihaozao 0.0256～0.0652mg/kg,0.20～0.36,0.0532 0.06381eaves of Broussonetia papyrifera Qi mg/kg,0.27～0.35,0.0300～0.0732 mg/kg, Taoyuan Daye from 0.21 to 0.33. Because of the same area of tea, there are some differences between the environmental condition of planting, the regularity in the natural environmentis not obvious, the need for laboratory tests of different tea varieties enrichment further analysis.(5) Pb, Cd content analysis of tea plant in northeastern Hunan Province in spring and summer seasonsComparison of Pb content in different parts of the two season of spring and summer tea,soil (spring 19.07～42.39mg/kg,20.85～44.26 summer (spring), the stem of 6.91 22.19mg/kg,7.56～24.87mg/kg in summer), old leaves (spring summer 3.40 6.06mg/kg,4.35～7.86mg/kg) Pb content in summer, slightly higher than the spring shoot, heart is on the contrary. Cd in soil in spring (0.128～0.272mg/kg) was slightly higher than that insummer (0.12～0.267mg/kg), old leaves (spring summer 0.0378～0.0620mg/kg, 0.0453～0.0720mg/kg) and stem (spring summer 0.0521～0.0802mg/kg,0.0664～ 0.0921mg/kg) Cdcontent in spring is slightly lower than in summer, the content of Cd in the shoots of springis the heart (0.0118-0.0232mg/kg) than in autumn (0.0086～0.0145mg/kg).