| In recent years,Xiang Jiang river has been seriously polluted by radioactive contamination,in 1978 it has become one of the most polluted rivers in China,form 2006 to 2007,in 40 provinces monitoring sections about water quality in Xiang Jiang river,The cross section was56%in 2006 and 50%in 2007.Most of the discharged pollutants from living pollution and industrial pollution are confined in a certain area.According to reports,the main stream of Xiang Jiang over Hengyang section,water quality is good,below Hengyang section is poor.Therefore,the Hengyang section has been chosen as the research area.Hengyang is located in the middle reaches of Xiang Jiang,it is a typical city which possess a large number of industries such as metallurgy and chemical industry,and the trunk stream of Xiang Jiang has 226 km in Hengyang section,which accounts for 39.7%of Xiang Jiang's mileage in Hunan province.Therefore,it is of great significance to study the water quality in the Hengyang section.In order to investigate the level and source of natural radioactive in the Hengyang section of Xiang Jiang river,so i respectively in dry season?11-12 months?and abundant season?4-6 months?,in four major tributaries in Hengyang section of Xiang Jiang river and this section of the river?Chong Ling river,Zheng river,Lei river,Mi river?,spots-setting,sampling,measuring and analyzing the activity concentrations of six kinds of natural elements(U?Th?226Ra?40K?210Po?210Pb)in river by contrast the date,finding out the source of abnormal natural radionuclide in river.All the work was carried out according to the latest national standard?GB 12999-91<regulations technical for the preservation and management of sample in water>GB 12998-1991<sampling technical guidance in water>GB 12997-1991<technical regulations on the design of water quality sampling scheme>HJ/T 91-2002<Specification for monitoring of surface water and sewage>and so on?the sampling work is carried out in combination with the actual situation of the sampling.For the measurement and analysis of 6 kinds of nuclides,reference the latest standard measurement methods in china.?GB6768-1986<Method For Analysis Of Trace Uranium In Water>GB11224-1989<Method For Analysis Of Thorium In Water>GB11214-1989<Method For Analysis Of Radium In Water>GB11338-1989<Method For Analysis Of Potassium In Water>GB12376-90<Electroplating Method For Analysis Of Polonium-210 In Water>EJ/T 859-94<Method For Analysis Of Plumbum-210 In Water>?Under this premise,I will do some corresponding adjustment according to the actual situation.(such as measurement and analysis of polonium-210 I had referenced<Analysis Po-210 in water>Environmental Monitoring Station in Zhejiang Province,For the measurement and analysis of Plumbum-210,Huang Zhan Chang's<rapid analysis of radionuclide activity of 210 Pb in environmental water>.The experimental results show that:?1?the mean values of 6 natural radionuclides in the Hengyang section of Xiang Jiang are respectively238U 0.37?g/L?232Th 0.047?g/L?226Ra 0.96×10-2Bq/L?40K 4.68×10-2Bq/L?210Po 0.26×10-2Bq/L?210Pb 1.30×10-2Bq/L,compared with the annual average of radioactivity level in Dong Ting Lake water system,226Ra,210Po,and 210Pb are 1.28,1.37,and 2.4 times the same,it shows that the Hengyang section of Xiang Jiang is indeed with radioactive contamination.This data is basically consistent with the results obtained from the measurement of six natural radionuclide concentrations in Xiang Jiang by Li Yue?2016?.?2?The measured value in the period of abundant water is generally higher than that in the dry period.Maybe because of the heavy rainfall during the flood season,all kinds of radioactive materials in the riverside are rushed into the river.?3?The activity concentration of 226Ra,210Po and 210Pb in the eleven sampling points are generally higher than the average value of Dong Ting Lake water system and the Yangtze River water system,The activity concentration of 226Ra,210Po and 210Pb in Chong Ling river are respectively 4.38×10-2Bq/L?0.47×10-2Bq/L?2.53×10-2Bq/L,it is 5.83,2.47,5.06 times the mean of the corresponding nuclide year of the Dong Ting Lake water system.The activity concentration of 226Ra,210Po and 210Pb in Zheng river are respectively 2.21×10-2Bq/L?0.46×10-2Bq/L?1.99×10-2Bq/L,it is 2.95?2.42?3.98 times the mean of the corresponding nuclide year of the Dong Ting Lake water system.The activity concentration of U and 40K is slightly lower than the annual mean of Dong Ting Lake water system and the Yangtze River water system,Most of the measured values of 232Th are far lower than the annual mean of the Dong ting Lake water system and the Yangtze River water system,the measured value?0.01?g/L?up Mi river never so such as one thirtieth about the Dong ting Lake water system and the Yangtze River water system,maybe because the Th element is more embody as fourth metal,in neutral or acidic solution easy to hydrolysis,formation precipitation or the lower radioactivity in the region.?4?the three sampling points for each branch,compare with Xiang Jiang which is before merged and after merged,we could found that the concentration of six nuclides in Chong ling river and Zheng river are respectively 1.54 times 1.53 times than Xiang Jiang river,It shows that the two regions have been seriously polluted,The other 2tributaries are quite different from Xiang Jiang,therefore,the 2tributaries have not been greatly polluted.To investigate whether there are pollutant source for Chung Ling river and Zheng water and why the Th element pollution source of radioactive concentration is lower,I have taken a detailed sample of the 2tributaries and collected the bottom mud for the above 11 points for further analysis.Because of the time,only the Chung Ling samples have been studied,the date shows that the concentration of radioactive element is regularly which is far away mine,near mine area,the radioactive concentration of each element in the water body is high,that the pollution sources in Chong Ling area is likely to pound the Shui kou shan mine. |
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