基于模糊数学的黄河内蒙古段水环境质量评价

Assessment of Water Environmental Quality in Inner Mongolia Section of Yellow River Based on Fuzzy Mathematics

[目的] 监测黄河内蒙古段5个监测地点，从上游到下游依次是三盛公、三湖河口、包头镫口、张立文尧、喇嘛湾，共24个监测断面，进而了解黄河内蒙古段水质现状。[方法] 选择溶解氧、化学需氧量、氨氮、总磷、总氮5个评价参数，运用模糊数学综合评价方法进行综合评价。[结果] 黄河内蒙古段水体中DO基本属于Ⅰ类水，其值在7.2～8.1 mg/L之间；COD总体上介于Ⅲ和Ⅳ类水之间，其值在17～33 mg/L之间；氨氮总体上接近Ⅲ类水，其值在0.5～1.3 mg/L之间；TP总体上介于Ⅱ和Ⅲ类水之间，其值在0.12～0.28 mg/L之间；TN基本超过Ⅳ类水，有的甚至超过Ⅴ类水，其值在1.4～2.7 mg/L之间；主要污染物为COD和TN。其整体呈现Ⅲ和Ⅳ类水，其评价值在3.3～4.2 mg/L之间。[结论] 通过评价发现，黄河内蒙古段水质有逐渐恶化的趋势，主要原因是外源污染的汇入。

[Objective] The sampling data from 24 cross sections of 5 monitoring sites, including Sanshenggong, Sanhuhekou, Baotoudengkou, Zhangliwenyao, Lama Bay, were used for studying the water quality of Inner Mongolia section of the Yellow River.[Methods] Choosing the dissolved oxygen（DO）, chemical oxygen demand（COD）, ammonia nitrogen, total phosphorous（TP） and total nitrogen（TN） to evaluate the water quality of the Yellow River by means of comprehensive assessment of fuzzy mathematics.[Results] DO was between 7.2 and 8.1 mg/L, which indicated that the water quality of the Yellow River belong to class I. COD varies between 17 and 33 mg/L, indicating the water quality between the class Ⅲ and Ⅴ. Ammonia nitrogen varies between 0.5 to 1.3 mg/L, water quality was within the classⅡand Ⅲ. TP was between 0.12 to 0.28 mg/L, water quality between the class Ⅱ and Ⅲ. TN was between 1.4 to 2.7 mg/L, and water quality was the class Ⅳ, even occasionally worse than that of the classⅤwater quality standard. COD and TN were the main pollutants. The water quality of Yellow River in Inner Mongolia are roughly in the class Ⅲ or Ⅳ, and its vale varies between 3.3 to 4.2 mg/L.[Conclusions] Through the evaluation, it is found that the water quality in the Inner Mongolia section of the Yellow River is gradually deteriorating. The main reason is the import of foreign pollutants.