Investigation On The Water Quality And Pollutants Outnet Intensity Of The Songhua River

Trans-boundary rivers and their important risk tributaries have always been the keyissues of international concern. Heilongjiang River is the Sino-Russian boundary riverand Songhua River is its main tributary. Songhua River belongs to the high risk exitriver owing to its special geographical location and long icebound period, as well as theserious structural risks caused for years.This paper takes the exit reaches of Songhua River (upstream of Jiamusi toTongjiang) and the middle reaches of Heilongjiang River at Sino-Russian boundaryriver (Small Heihe to Fuyuan) as the study objects. Through the statistical analysis ofthe environmental background survey, environmental statistics, pollution source censusand historical data, along with the situation monitoring data of water quality and waterquantity, the water quality situation of the exit reaches of Songhua River and the middlereaches of the boundary river, as well as the effects of potassium permanganate index，ammonia nitrogen and the characteristic organic pollutants of Songhua River on thewater quality of the boundary river are investigated.In order to solve the water quality assessment problem of high risk and lightpollution river, both evaluation methods of the single factor and the organic pollutioncomprehensive index were compared based on the analysis of existing water qualityanalysis and evaluation methods. The former was evaluated the highest safety and thelatter could most relfect the ecological restoration ability. The coupling method ofsingle factor and organic pollution comprehensive index was established as the waterquality analysis mode，in view of the combined use of the two methods. The monitoringdata of Heihe upper section in2009was used to assess the accuracy and feasibility ofthis model that was applied to analyse the water quality of Songhua River andHeilongjiang River. Results showed that the method was applicable to the water qualityassessment of surface water with high dissolved oxygen and potassium permanganateindex such as Songhua River and Heilongjiang River.The pollution was not clear and the pollution source was unknown for the exitreaches of Songhua River and the middle reaches of Heilongjiang River at Sino-Russianboundary river. In order to ascertain the water quality situation of the exit reaches andprovide decision support for our country,10monitoring sections were set in the highrisk exit reaches of Songhua River in this paper. The prescribed method in the book ofMonitoring and Analysis Method of Water and Waste Water (fourth update edition) wasadopted and more than300samples were collected during2009to2010. Thepretreatment of the organic compounds monitoring samples was ifnished through themethods of liquid-liquid extraction, solid phase extraction and so on. The qualitativeand quantitative analysis of the characteristic organic compounds was carried out.10sections were evaluated respectively by using the new coupling model of water quality assessment. Results showed that the exit reaches of Songhua River and the boundaryriver reaches (Small Heihe to Fuyuan) were slightly polluted. The main pollutants werepotassium permanganate index and total nitrogen in wet season, total nitrogen andammonia nitrogen in dry season. The analysis of pollution source indicated thatupstream water of Songhua River and Heilongjiang River, non-point source pollutionand the discharge of domestic sewage were the main reasons for the pollution of the exitreaches of Songhua River and the boundary river reaches (Small Heihe to Fuyuan).The unknown inlfuence degree of Songhua River on the boundary HeilongjiangRiver was explored by means of estimating the export lfux, and the export fluxes ofthe characteristic pollutants such as potassium permanganate index，ammonia nitrogenand di-n-butyl phthalate were estimated. Results showed that the kinds of organicpollutants in the exit reaches of Songhua River were more than those in the boundaryriver. In the absence of external tributaries into river, the river length had a positiverelationship with the kinds of adsorbed and degraded organic compounds, and thedetectable concentrations of various characteristic organic pollutants were low. Thehighest concentration was less than50%of the national standard value and the vastmajority of organic compounds were less than0.5%of the value. By export lfuxcalculation, the following conclusions were drew that potassium permanganate indexflux and lfow were positively correlated, and potassium permanganate index flux permonth was up to72.8kt in wet season, while ammonia nitrogen flux was wet season>icebound season> median water period. Di-n-butyl phthalate reached the highest lfux of389.6t/a (2009) and the rest of the organic pollutants were not more than lt/a inaddition to phthalic acid esters in2011. The research on the contribution rates of thecharacteristic pollutants suggested that the contribution of the characteristic pollutantsfrom the exit section of Songhua River to Tongjiang section to the boundaryHeilongjiang River was small, presenting the trend of decline year by year.