沈阳市水功能区水质现状评价及水质变化趋势成因分析

Assessment on water quality statuses in water function zones and analysis on causation of water quality changing trend in Shenyang

针对仅用水质达标率并不能全面评价区域水资源保护现状的问题,根据沈阳市18个水功能区2012—2015年的监测历史资料,利用达标率法和基于改进的变权物元可拓模型对水功能区水质现状进行了综合评价,并在阐明水质达标率和综合水质变化趋势基础上,利用灰色关联和贡献率法分析了沈阳市水功能区水质产生变化的主要贡献因子。结果表明:沈阳市水功能区水质有快速好转的趋势,但现阶段达标率仍普遍偏低,其中BOD_5、NH_4^+-N达标率较低,18个水功能区平均值仅为66.7%和66.9%;水质好转的潜在影响因子的大小排序是:COD>COD_(Mn)>BOD_5>NH_4^+-N,但前3者对水功能区综合水质改善的贡献不大。NH_4^+-N是最主要的贡献因子,平均贡献率达161.8%,因为NH_4^+-N的生产弹性虽不大,但其单项水质增幅明显。研究成果可为评价沈阳市水功能区水质现状和明晓今后工作方向提供参考。

Aiming at the problem of that the regional water resources protection status cannot be fully assessed only with water quality standard-reaching rate,the water quality statuses of the water function zones in Shenyang are comprehensively assessed with the method of standard-reaching rate and based on improved matter-element extension model with variable weight in accordance with the historical monitoring data of 2012-2015 of 18 water function zones in the city.And then the main contribution factors for the changes of the water quality in the water function zones are analyzed with both grey relational analysis and contribution rate analysis on the basis of expounding the water quality standard-reaching rate and the comprehensive water quality changing trend.The result shows that the water qualities of the water function zones in Shenyang exhibit rapid improving trends,but the standard-reaching rates are generally lower therein at present;in which the standard-reaching rates of BOD_5and NH_4~＋-N are lower and the mean values for the 18 water function zones are only 66.7%and 66.9%,while the order of the potential impacting factors of water quality improvement is CODCOD_（Mn）BOD_5NH_4~＋-N.However,the contributions of the first three to improving the comprehensive water quality of water function zone are not so large.NH_4~＋-N is the most important contribution factor with the mean contribution rate up to 161.8%,because of that though the production elasticity of NH_4~＋-N is not large,the water quality increment of single item is remarkable.The study result can provide references for assessing water quality statuses of water function zones in Shenyang and realizing the working orientation in the days to come.