Residue Investigation Of Organochlorine & Pyrethroid In The Chief Tea Regions Of Chongqing

As a drink, tea is abundant in caffeine, proteins, amino acids, vitamins and so on, so it processes the function of refreshing, detoxifcation and life-prolonging. The history of tea civilization is very long, and the custom of tea-drinking spreads widely in China. Meanwhile, China is also a great country in tea production and export. With the improving of standard of living and sense enhancing of environment and health, people in nowadays prefer the food rich in nutrition and non-pollution. But during the growth of tea trees, many people employ chemical pesticides to control plant diseases and insect pests. Therefore, people pay more attention on pesticides residue in tea.Chongqing is one of the important tea production bases in China. In Chongqing, the first choice to the harmful creature is chemical control, and the key point is pest control. However, the unreasonable pesticide application brings residue problem. For the goal of realizing the anniversary pesticides residue and providing a theory for the choice of high quality tea gardens, the author develop the research of the chief tea regions in Chongqing, the tea gardens as follows: Banan, Wansheng, Yongchuan, Rongchang, Wanzhou and Dianjiang, and the objects of the research are soil, leaves of tea and tea for sale. The main results are as follows:1 Control of pest and the employment of conventional pesticide and acaricide in the chief tea gardens of ChongqingAccording to the investigations of Banan Ersheng, Wansheng Genggu, Rongchang Tiangangyuye, Yongchuan Yunling, Wanzhou Phenix and Dianjiang Dongyin tea gardens and the plant protection departments in Chongqing, the results indicate that insect pests are more prominent than disease during tea trees growth. The chief pests are Empoasca flavescens (Fab.), Polyphagotarsonemus latus(Banks), Euproctis pseudoconspersa Strand, Adoxophyes orana Fischer von Roslerstamm and Ectropis oblique hypulina Wehrli, et al, while Icerya purchasi Maskell, Aleurocanthus spiniferus (Quaintance) and Toxoptera aurantii Boyer happen partly. Most of the pests happen heavily in summer and autumn, less happen in spring.The single style pesticide which is high effect and low toxicity is used widely in most of tea gardens in Chongqing, such as Beta-cypermethrin and Imidacloprid; The widely-used pesticides (Endosulfan) are used less and less; The conventional pesticides are alternated by Environment-friendly pesticides; lime-sulfur is still used in many tea gardens in winter; Emulsifiable concentrates are the more popular than other pesticide formulations. High dose pesticides employing happen frequently.2 Investigations of Organochlorine & Pyrethroid residue in the chief tea regions of Chongqing2.1 Soil Information of six tea gardensThe soil average pH are from 3.58 to 5.61 in the six tea gardens. The soils in Wanzhou Phoenix tea garden and Dianjiang Dongyin tea garden are more beneficial to tea trees growth than other tea gardens.The average Organic matter content are between 2.22 % to 6.19 % in the six tea gardens.The soil in Banan Ersheng, Wanzhou Phoenix and Dianjiang Dongyin tea gardens are all yellow soil, and the soil in Rongchang Tiangangyuye and Yongchuan Yunling tea garden are brown and purple mud, and purple soil in Wansheng Genggu tea garden.All the soil are medium weight soil in the six tea gardens, but soil in Rongchang Tiangangyuye is light weight.2.2 Detection results of Organochlorine & Pyrethroid residue in soil, freshtea leaves and tea on saleHCHs residue in six tea gardens range from 0.002 mg/kg to 0.019 mg/kg, the mean is from 0.0009 mg/kg to 0.0027 mg/kg; DDTs residue detected in Yongchuan soil sample is from 0.002 mg/kg to 0.003 mg/kg, the mean is 0.0011 mg/kg; Alpha-cypermethrin residue is from 0.009 mg/kg to 0.052 mg/kg, the mean is from 0.013 mg/kg to 0.022 mg/kg. The organochlorine residues in six tea gardens of Chongqing are all under 0.2 mg/kg the criterion of MRL (Maximum Residue Limit) in non-pollution tea gardens in China, but all are beyond the criterion of organic tea garden in China.HCHs are not detected in fresh tea leaves, while DDTs residue in fresh tea leaves is from non-detected to 0.022 mg/kg, and the mean is from non-detected to 0.0098 mg/kg; And alpha-cypermethrin residue is from non-detected to 0.007 mg/kg, the mean range from non-detected to 0.0023 mg/kg.HCHs residue in tea on sale is from 0.013 mg/kg to 0.028 mg/kg, the average is from non detected to 0.0127 mg/kg. The HCHs residues in tea on sale are all under 0.2 mg/kg the criterion of E.U. (European Unite), but all beyond 0.01 mg/kg the criterion of Japan. The average residue values are all under the criterion of Japan, except that the sample in Banan is beyond criterion of Japan; DDTs residue range from non-detected to 0.061 mg/kg, and the mean is from non detected to 0.032 mg/kg. DDTs residue are all under 0.2 mg/kg the criterion of E.U., but are all beyond 0.01 mg/kg the criterion of Japan except the tea samples in Wanzhou and Rongchang of Chongqing. The means of DDTs residue in the tea samples of Banan, Wansheng and Yongchuan are all beyond the criterion of Japan; The most of the tea samples are lack of Pyrethroid residue, except the spring tea sample in Yongchuan, 2006. We have found fenpropathrin, alpha-cypermethrin and fenvalerate residues in tea sample of Yongchuan, 2006, and the residues of the three all all beyond the criterion of Japan, while fenpropathrin and fenvalerate residues are beyond the criterion of E.U..Moreover, there is an alpha-cypermethrin residue law in soil, fresh tea leaves and tea on sale from August to December, 2005. It is: residue in soil>residue in fresh leaves>residue in tea, and we also make a recommendatory dose of alpha-cypermethrin. It is better to be used 0.087 g/hm~2. Dongyin tea garden of Dianjiang is recommended as a high grade base of tea production.