The Analysis Of Dichloromethane, Chloroform And Toluene In Liang Jiang, Min Jiang River With GC-MS

Environmental problem is one of the most serious challenges in the twenty first century. The environmental problem of organic pollutant has been attracting people's attention increasingly. Dichloromethane, trichloromethane and toluene are environmental priority pollutants, even the carcinogenic contaminants. The Min River is one of the five tributaries of Yangtze River. It is also the first grade river in Sichuan province. The article reveals the distribution characteristics of Dichloromethane, trichloromethane and toluene in winter, by adopting the methods of the purge and trap method in combination with gas chromatography mass spectrometry. The following four conclusions are achieved.1.Improved the approach of analyze Dichloromethane, trichloromethane and toluene in water. The Minimum detection limit (MDL) of Dichloromethane is 0.01μg/L, the RSD is 1.12%, and the recovery is 102.20%. The Minimum detection limit (MDL) of trichloromethane is 0.02μg/L, the RSD is 4.20%, and the recovery is 89.99%.the Minimum detection limit (MDL) of toluene is 0.02μg/L, the RSD is 2.06%, and the recovery is 102%.2.The following is the integrated distribution characteristics of the three toxic pollutants in the Min River. Dichloromethane can be found below 10.7°C; the concentration increases with the decreasing of the temperature; the average concentration is 0.8963μg/L. Trichloromethane can be found below 12.0°C; the concentration does not change much with the change of temperature; the average concentration is 0.5512μg/L. On account of sample inadequate, the toluene was found in only one place, and the concentration is 0.2507μg/L。Dichloromethane and chloroform were positive correlation with the pH, but toluene has a very small correlation with the pH. Dichloromethane was negative correlation with DO. When DO was below 10.0mg /L, the concentration of dichloromethane decreases as the increase of DO. Chloroform was negative correlation with DO, as the DO changes, it's keeping 0.5512±0.123μg/ L. 3.Dichloromethane, chloroform, toluene's quality parameters did not exceed the required quality standards, which are in conformity to the standards of collecting potable water, surface water and water head area.4.Combined with the environmental characteristics of the Min River, the article presents the policies on preventing the organic toxicant, formulating the preventing purposes and controlling technique. Giving priority to protection of the headwaters of drinking water; strengthening the management of pollution sources; protecting the water quality of the Min River; improving the urban environment work; solving the problem of sullage and garbage siege; paying attention to the protection of ecological environment of the Min River.