“十一五”期间中国化学需氧量减排与水环境质量变化关联分析

化学需氧量是中国主要污染物总量控制指标之一。分析化学需氧量排放变化及减排形势对今后化学需氧量及其他污染物减排具有借鉴意义。在分析＂十一五＂期间中国化学需氧量减排趋势和水环境质量变化趋势的基础上,定量和定性地考察两者之间的关系。结果表明：＂十一五＂期间化学需氧量排放量呈下降趋势,但生活化学需氧量排放量比重有所上升,中西部地区排放量下降趋势比东部地区要小;化学需氧量减排目标顺利实现,其中,工业源是减排主体,东部地区对减排贡献最大;中国地表水环境质量逐步改善,高锰酸盐指数质量浓度累计下降31.9%,Ⅰ～Ⅲ类水质断面比例累计提高14.4个百分点。无论是全国尺度还是流域尺度,随着化学需氧量排放量的减少,地表水水质均出现不同程度的改善,两者表现出一定程度的正相关关系,但是部分流域存在污染物排放总量与环境质量变化不完全协同的现象。

Relation between water quality and COD discharge in China in the Eleventh Five-Year Plan

COD is one of the indicators of total amount control of main pollutions.It provides the theory and realistic reference meaning for pollutions reduction to investigate the changing trend and reduction situation of COD.When studying the COD reduction trend and water quality changing trend the correlation between them is examined.The results are summarized as follows.①The COD discharge decreased but the proportion of COD discharge in life increased during the ＂Eleventh Five years＂ period while the COD reduction rate of the midwest regions was lower than that of the eastern region.②The COD reduction goal in ＂eleventh five-year plan＂ had been achieved.Seen from the source,the industrial COD discharge made a greater contribution to reduction.Seen from the region,eastern region made a greater contribution to reduction.The water quality had been improved in basin and nationwide as decrease of COD.The concentration of permanganate index had decreased by 31.9% and the proportion of surface water sections under national monitoring program met grade Ⅰ to Ⅲ had increased by 14.4 percentage point.There is a significant positive correlation between the water quality and COD discharge,but for some basins there is not complete correspond between the pollution discharge amount and environment quality changing.