• 关键词：黄河  水污染  化学需氧量(COD)  有机质

• 基金项目：国家自然科学基金会;水利部黄河水利委员会联合资助基金项目(批准号:No.E0950239010)

• 陈静生
• 北京大学环境学院, 北京 100871

• 张宇
• 北京大学环境学院, 北京 100871

• 于涛
• 北京大学环境学院, 北京 100871

• 何大伟
• 北京大学环境学院, 北京 100871

• 摘要：对黄河自潼关至三门峡至花园口河段泥沙中有机质的含量、组成、溶解特性和降解特性及对河水COD值与泥沙有机质的关系问题进行了研究.查明了:1)黄河泥沙中的有机质主要富集于<5μm的细颗粒物中;2)这一段黄河水中溶解态有机质在总有机质中的比例非汛期为20%-25%, 汛期为5%-10%;3)黄河泥沙中的有机质75%-80%以上是既不能为酸也不能为碱所萃取的胡敏素物质;4)在黄河水中可被生化降解的有机质只占总有机质的1%-3%;5)目前在黄河清洁河段测得的COD值经常高达数十、数百、甚至上千mgL, 几乎等同于河水泥沙含量与泥沙中有机质含量的乘积.研究结果表明, 黄河泥沙中的有机质是稳定性极好的天然腐殖质类物质, 它们在COD监测方法规定的高温、强酸性和强氧化剂条件下可以被氧化, 构成黄河COD值的主体, 但在实际自然条件下氧化过程极为缓慢和有限, 不会对水体产生污染危害, 不能将其与通常概念上的耗氧性有机污染物混为一谈.测得后未经泥沙有机质背景值校正的COD值不是评价河流污染程度的恰当的水质指标, 应寻找更好的水质参数来反映和评价黄河水的有机污染状况.

• Abstract：This paper studied the contents, components and the characteristics of dissolution and degradation of the organic matters in sediments of the Yellow River. Studies were also carried out on the relationship between COD values of the River water and the contents of organic matters in sediments. The results demonstrated that: 1) the organic matters in the Yellow River sediments are mainly enriched in particulates with size <5μm; 2) the percentage of the dissolved organic matter in the River water with respect to the total organic matters is 20%-25% in the non-flood season, and 5%-10% in the flood season; 3) over 75%-80% of the organic matters in sediments of the Yellow River is not soluble; 4) the bio-degradable organic matter accounts only for 1%-3% of the total organic matters; 5) presently, the COD values detected in the unpolluted reaches of the Yellow River are often as high as thousand mg/L, nearly equal to the product of the sediment content in the River water and the organic matter content in sediments of the River. On the basis of the above results, the authors pointed out that the organic matters in sediments of the River are natural humic substances that are stable. They make up of the principal part of the COD in the River water and could be oxidized under the conditions of high temperature, strong acidity and strong oxidant which were used in the regular method to test the COD. The oxidation process of these substances, however, is quite slow and limited in natural conditions, and will not produce contamination to the River water. So the organic matters in sediments should not be confused with generally believed oxygen-demanding pollutants. COD is not a suitable index to reflect and evaluate the water quality of a river with excessive silt; better water quality parameter is to be found to reflect and evaluate the real polluting situation caused by oxygen-demanding organic substances in the Yellow River.

• Key words：Huanghe (the Yellow River)  water pollution  chemical oxygen demand  organic matter

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