熵权法模糊物元模型在养殖水质评价中的应用

为客观综合评价养殖水体质量,利用熵确定水质指标权重,结合物元分析理论及贴近度的概念,构建养殖水质复合模糊物元模型,对2015—2019年监测的上海地区635批次养殖水样进行地表水环境质量等级分类。水质监测结果显示,池塘水体的pH、总磷、高锰酸盐指数、As(砷)和叶绿素a平均含量显著高于引水河道的(P<0.05),硝酸盐氮、Zn(锌)和石油类的平均分布显著低于后者(P<0.05),其他指标的平均分布差异不显著(P>0.05)。不同养殖品种池塘水体间,淡水鱼塘水体中氮、磷、有机质等相关指标的平均含量最高,蟹塘水体pH均值最高。熵权法模糊物元模型评价结果表明,在养殖水体水质指标中pH的权重最高,其次为高锰酸盐指数、总氮和氨氮,这4项合计权重超过0.5;89.29%的鱼塘、87.91%的虾塘和75.83%的蟹塘水样水质类别属于或优于地表Ⅲ类,相关河道水样水质满足地表Ⅲ类水质标准的样品占比达98.72%。整体上,上海地区的养殖水质满足地表水环境功能要求。

Application of fuzzy matter-element model based on entropy weight method in water quality assessment of culturing ponds

To evaluate aquaculture water quality objectively and comprehensively,the method of entropy was used to determine index weight,and a compound fuzzy matter-element model was established on the basis of the fuzzy matter-element theory and the concept of the Euclid approach degree.Six hundred and thirty-five batches of aquaculture water sample collected in the period between year 2015 and 2019 were classified according to surface water quality by the method of compound model.Water quality monitoring data showed that mean values of pH,total phosphorus,permanganate index,arsenic,and chlorophyll a in pond water were significantly higher than those in the diversion channel water,while average levels of nitrate,zinc,and petroleum were all significantly lower than those in the channels.For water quality differences between ponds cultured fishes,shrimps or crabs,average concentrations of nitrogen,phosphorus and organic matter related indexes were highest in freshwater fish culture ponds,and water pH was highest in crab culture ponds.Results of fuzzy matter-element model showed that the weight of pH was highest in all water quality indices,followed by permanganate index,total nitrogen,and ammonia nitrogen,with a combined weight exceeding 0.5.The proportion of water samples in fish,shrimp and crab pond which belonging to or superior to class Ⅲ of surface water quality was 89.29%,87.91%and 75.83%respectively,and the percentage of diversion channel water samples was 98.72%.These results means that the aquaculture water quality of Shanghai satisfied its surface water function requirements overall.