| Metiram belongs to a great prophylactic synthetic fungicide. The soluble granulated material which includes 70% metiram, its trade name is Pinrun. In recent years, Pinrun was widespread used in our country,specially in the south area. Previous studies focused mainly on its prevention and cure to the diseases of fruit and vegetable plants, little information was available about its residue behavior and the toxicity effects. In order to provide some fundamental data for assessing the environment safety and scientific application, the degradation of metiram and ETU in orangery, the toxicity effects of ETU on Daphnia magna, the toxicity effects of Pinrun on Lemna paucicostata and Misgurnus anguillicadatus were studied, under control conditions by simulating methods in laboratory. The main results were follows:Firstly, The gas chromatograph analysis method was used as the residue analysis method for metiram in orange and soil. Samples containing metiram were placed in hemetic vials and heated. The metiram reacted with HCl/SnCl2 and Produced CS2. The solution of CS2 was then analysed by gas chromatograph. The amount of CS2 was a scale of metiram residues on various media, what was accepted for describing the residue magnitude of metiram worldwide. After detecting, it was showed that the minimum detectable amount of metiram was 1.9×10-10g. Furthermore, the lowest detectable concentrations of metiram in the orange skins, the orange meat, the entire fruit and the orangery soil were 0.06mg/kg,0.05mg/kg,0.05mg/kg and 0.06mg/kg, respectively. When the added amount of metiram is changed from 0.5 to 5.0 mg/kg in sample, the average recoveries of the metriam on the orange skins, the orange meat, the entire fruit and the orangery soil were changed from 86.15% to 96.95%,86.28% to 101.97%,81.61% to 91.89% and 88.90% to 106.26%, respectively. The coefficient of variations were changed from 5.38% to 7.62%,4.19% to 8.02%, 2.36% to 6.19% and 5.28% to 9.64%, respectively. The method validation data well fitted the analytical criterion for pesticide residue.Secondly, the residue analysis methods for ethylenethiourea (ETU) in orange and soil were established. The ETU residues in samples were extracted by methanol. Then the extract was purified by a chromography column which was filed with the mix-material of aluminum oxide and florisil. For determination of ETU in samples, a HPLC with UV detector was use. After detecting, it was showed that the minimum detectable amount of ETU was 1.2×10-10g. Furthermore, the lowest detectable concentrations of ETU in the orange skins, the orange meat, the entire fruit and the orangery soil were O.Olmg/kg, O.Olmg/kg, 0.009mg/kg and 0.008mg/kg, respectively. When the added amount of ETU is changed from 0.1 to 2.0 mg/kg in samples, the average recoveries of the ETU on the orange skins, the orange meat, the entire fruit and the orangery soil were changed from 91.35% to 98.04%,91.98% to 94.66%,83.85% to 88.56% and 87.55% to 93.71%, respectively. The coefficient of variations were changed from 3.87% to 5.17%,4.17% to 5.23%,1.98% to 5.38% and 4.15% to 5.48%, respectively. The method validation data well fitted the analytical criterion for pesticide residue.Tirdly, the reside decline behaviors of Metiram and ETU were studied in orangery in Hunan, Zhejiang and Guizhou province for two years. And the results revealed that the decline rules of Metiram and ETU changed as well as the exterior surroundings changed. In year 2007, the decline half-lives of Metiram in soil planted orange in Hunan and Zhejiang were 27.61 days and 7.16 days, respectively. The decline half-lives of Metiram in orange in Hunan and Zhejiang were 9.55 days and 8.39 days, respectively. In year 2008, the decline half-lives of Metiram in soil planted orange in Hunan and Guizhou were 11.53 days and 14.94 days, respectively. The decline half-lives of Metiram in orange in Hunan and Guizhou were 11.23 days and 7.63 days, respectively. It was showed that the decline of Mentiram in orangery was pretty quick. Also, the residue amount of Metiram depends on many factors such as the sprinkling quantity and times. Normally, the residue amounts of Metiram in both soil and orange were higher at a great and frequent sprinkling quantity. Then for the sampling time, the residue amount obviously represents a direct correlation with the time interval between sampling and sprinkling. That is to say:the shorter the interval, the higher the residue amount. In addition, it was detected that the ETU residue amount could hardly be found in whole samples.Fourthly, static and half static experiments were performed to study the toxicity effects of Pinrun on Lemna paucicostata and Misgurnus anguillicadatus. The results showed that IC50 value influenced by Pinrun unden different tested time (24,48,72 and 96h) were 11.75,4.31,3.29 and 2.67mg/L. The low concentration or the short duration of action promoted the growth of Lemna paucicostata, and the high concentration or long duration of action inhibited its growth. The results also showed that LC50 value influenced by Pinrun unden different tested time (24,48,72 and 96h)were 100.26,29.29,19.63 and 15.14 mg/L, the safe concentration(SC) was 0.2190mg/L. The toxicity rank of Pinrun on Misgurnus anguillicadatus was high.Fifthly, static experiment was performed to study the toxicity effects of ETU on Daphnia magna. The results-showed that EC50 value influenced by ETU unden different tested time (24 and 48h) were 1.14,0.64g/L. LC50 value influenced by ETU unden different tested time (24 and 48h) were 344.49,3.49g/L,the safe concentration(SC) was 10.62mg/L.The toxicity rank of ETU on Daphnia magna was weak. |
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