物元可拓法在湖泊水质评价中的运用

APPLICATION OF MATTER ELEMENT ANALYSIS TO THE EVALUATION OF LAKE WATER QUALITY

选取3个主要水质监测指标,运用物元模型对长江中下游45个主要湖泊水质进行综合评价,结果显示:长江中下游地区被评价的45个湖泊中,没有Ⅰ类水质湖泊,Ⅱ类水质湖泊数占被评价湖泊数的2.22%,Ⅲ类水质湖泊数占被评价湖泊数的31.11%,Ⅳ类水质湖泊数占被评价湖泊数的28.89%,Ⅴ类水质湖泊数占被评价湖泊数的37.78%,其中水质超过地表水Ⅲ类水质标准的湖泊数占被评价湖泊数的66.67%,总体看来,长江中下游地区湖泊水质总体上较差。将评价结果与湖泊富营养化等级进行对照,结果显示:物元模型评价结果的Ⅳ类和Ⅴ类水质湖泊全部与富营养化等级为富或重富的湖泊相吻合,部分评价结果为Ⅲ类水质的湖泊也存在富营养化等级为富的现象,因此,长江中下游湖泊的富营养化现象对湖泊水质有潜在的危害。

There are 651 lakes along the middle-lower reaches of the Yangtze River and these lakes have potential effects on water resource and ecological environment.Three water indices(TP,TN and COD) were selected based on matter-element theory.Water quality of 45 lakes in the middle-lower reaches of the Yangtze River was evaluated.No one lake was up to Ⅰquality standard(GB3838-2002);one lake reached the quality Ⅱ and its ratio was 2.22%;14 lakes met the quality Ⅲ and its ratio was 31.11%;13 lakes fited to the quality Ⅳ and its ratio was 28.89%;and 17 lakes reached the quality Ⅴ and its ratio was 37.78%.All in all,30 of all studied lakes(66.67%) were beyond the Ⅲ grade.As a whole,water quality of 45 lakes in the middle-lower reaches of the Yangtze River was not good.Additionally,eutrophication is one of the most important factors to affect water quality of lake and reservoir.When the results based on the matter-element theory were compared to the results from the water eutrophic evaluation,we found that most studied lakes within water quality Ⅳ and Ⅴwere in accordance with rich or heavy rich type.The results indicated that water eutrophication has great potential threaten to water quality of lakes in the middle-lower reaches of the Yangtze River and matter-element theory is a simple,practical method for water quality evaluation.