洞庭湖湿地净化污染物的研究

Study on Purifying Contaminations in Everglade of Dongting Lake

利用洞庭湖水文观测站、环境监测站和实地考察资料,分析了洞庭湖湿地对水污染的净化功能。结果表明:每年输入湿地TN 67 0132.47 t,TP 41 103.85 t;输出与净化TN 116 033.27 t,TP 6 892.25 t;贮留净化率分别为17.31%和16.77%;COD输入317 849.26 t,输出3072641.97 t,贮留净化率3.086%;重金属元素、有污染的无机和有机化合物输入量10156.616 t,输出量9732.775 t,贮留净化率4.36%;在输入洞庭湖湿地的污染物中,有54.76%N,44.30%P,81.83%COD和95.59%重金属元素和化合物来自四水(湘、资、沅、澧4条江河)和三口(长江分洪流入的松滋、藕池和太平3口),有94%～99%的污染物是由面源污染引起,点源污染只占1%～6%,因此,在洞庭湖湿地水污染的治理上,控制系统外水系输入比控制湿地周边更重要,控制面源污染比点源污染更重要。

This article analyzed water contaminations purifying functions in everglade of Dongting Lake, based on investigate data from hydrological observation station of Dongting Lake, environmental monitor station and spots examine. ResuIts show that： annually input of TN to everglade of Dongting Lake was 670 132.47 t, TP was 41 103.85 tloutput and purifyed TN was 116 033.27 t, TP was 6 892.25 t;reserved purifying ratio was 17. 31% and 16.77% ;COD input was 317 849. 26 t, output was 3 072 641.97 t, reserved purifying ratio was 3. 086%. The total of heavy metal elements, inorganic and organic contaminations input was 10156. 616 t, output was 9 732. 775 t,reserved purifying ratio was 4. 36%. The 54.76% of N, 44.30% of P, 81.83% of COD and 95.59% of heavy metal elements, which inputed into everglade of Dongting Lake contaminations, was come from Xiang river, Zi river, Yuang river, Li river and three Changjiang river flood input mouth. 94%-99% of contaminations was area polluting resources, point polluting resources only 1% -6%. So it is more importtant to control input from out system than control input from everglade circumjacent area, viewed from strategically control contaminations in everglade of Dongting Lake. Control area pollution was more important than control point pollution.