Study On Pollution Characteristics And Self-Purification Behavior Of Panjin Section Of Liaohe River

Panjin section of Liaohe River, located in Liaohe River delta, is an important water ecosystem in the Liaohe River Wetland. Since overemphasizing economic development and ignoring environmental pollution in the last decades, Liaohe River suffered the serious pollution. Recently, with the government focusing on the water environmental protection, the serious pollution in Liaohe River has been relieved. Since 2005,the water quality of Liao River began to improve. Until 2013, the water quality of the main stream of Panjin section, such as Xing'an Section, Shuguang Bridge and Zhaoquanhe Section, has been improved from Level V to Level IV of Surface water environmental quality standard of China. To continuously advance the water quality of the Panjin section, it is required to study its pollution characteristics and self-purification activity.Based on this, firstly, the current pollution status, the surrounding environment and the local development situation were investigated. Principal component analysis method was applied to assess the pollution situation of this section during the dry, wet and normal level period, by which the ratio of the pollutants during the three period was determined to obtain the major contaminants.The initial concentration of pollutants discharged from sewage treatment plants nearby and their concentration in the Panjin section were investigated to figure out the containment elimination amount. The water quality model was used to calculate the water environmental capacity value in 2013. The results suggested that the actual emissions were less than the water environment capacity, indicating that the self-purification of water body in this section was playing a significant role in reducing pollutants.To further assess the self-purification activity of this section from 2007 to 2013, a one-dimensional water quality model was established with setting the two key parameters, oxygen consumption coefficient and complex oxygen coefficient. The self-purification coefficient of water body of this section was calculated to determine the contribution of the self-purification to the water pollutants reduction. The results showed that the self-purification coefficient of the section increased year by year, which indicated that the self-purification ability of Panjin section of the Liao River made more contributions to the water quality improvement.