Dongchanghu Pollution Sources And Water Quality Evaluation And Protection Countermeasures

Dongchang Lake, the largest artificial freshwater lake in north of the Yangtze River,plays a pivotal role in sustainable development of economic, social and ecologicalenvironment for Liaocheng city. At the same time, as a typically water-shortage artificiallake in northern cities, researches in pollution sources parsing, water quality assessmentand water environment protection of Dongchang Lake gave very important reference to themanagement and improvement for ecological environment of other lakes in northern cities.In this study, pollution sources of Dongchang Lake were comprehensively parsed.Dynamic variation of water quality, priority pollutants, and eutrophication were analyzedthorougly based on the monitoring data in recent10years. Besides, in view of mainexisting management problems of Dongchang Lake, water protection countermeasures andenvironmental management suggestions were put forward in the end. The results showedbelow:(1) Three pollution sources, such as drain outlet near CPPCC of Dongchangfu district(abbr. CPPCC-DCF) in3#region, peanut process plant and carnivorous workshop in1#region of Dongchang lake were confirmed by means of data collecting, telephoneinterviewing, field-visiting and laboratory analyzing. Furthermore, on the basis of theequi-standard pollution load evaluation and pollution load ratio of pollution sources andpollutants, the drain outlet near DCPPCC-DCF was found to be the main pollution source.In view of the pollution level of each pollutant, CODCrand TP were the major pollutantsamong three pollution sources, Ammonia gave less pollution impact on Dongchang Lake.(2) The single factor index (abbr. SFI) of pH in four monitoring sites (such asDongguan Bridge, Xiguan Bridge, Nanguan Bridge and Beiguan Bridge) displayedfluctuating downward trend, which was nearly in line with Grade â…£ standard ofGB3838-2002. SFI of DO met Grade â…£ standard completely in each monitoring site. TheSFI of CODCrshowed firstly-rising and then-declining trend. For example, which rangedfrom1.2to1.7in2004~2006, then reduced to0.6in2012. The SFIs of TP and TN alsotook on firstly-rising and then-declining trend. SFI of TP met Grade â…£ standard exceptfor2009(SFI of TP about1.5). SFI of TN changed between1and2, exceeded Grade â…£ standard, and the peak appeared in2007and2009(SFI of TP about2.0). From the view ofintegrated pollution, Nemerow index presented a declining trend, which implied the waterquality became better. Nemerow index became lower in the sequence of Dongguan,Nanguan, Xiguan, and Beiguan Bridge. Dongguan Bridge made greatly negative effects onwater quality of Dongchang Lake. The major pollutant of each monitoring site changedfrom CODCrto TN.(3) pH and DO from four monitoring sites were in accordance with Grade â…£standard during2004~2012. SFI of CODCrwas about1.1in summer and autumn, higherthan that in spring and winter. The SFI of TP was higher in summer than in winter. Whichof three monitoring sites were superior to Grade â…£ standard except to Dongguan Bridge.The SFI of TN, higher in summer and winter, ranged from1.47to2.19, was far worse thanGrade â…£ standard in each season. Thus TN was the major pollutant. Moreover, waterquality from each monitoring site was worse in summer and winter than in spring andautumn. Nemerow index of Dongguan Bridge, nearly2times more than Grade â…£standard, was highest in each season. The Nemerow index of the rest monitoring sites wasranged from1to1.5. In summary, Dongguan Bridge made the greatest impact on waterquality of Dongchang Lake.(4) The SFI of pH and DO from four monitoring sites was basically in accordancewith Grade â…£ standard in each month during2004~2012. The SFI of CODCrnearlyreached Grade â…£ standard except from July to September. The SFI of TP showed afluctuating downward trend. TP bascically met Grade â…£ standard except for April (SFI ofTP=1.2). The SFI of TN took on a fluctuating declining trend from March to December,and the peak appeared in July. The content of TN was more than that of Grade â…£standard. The Nemerow index, ranged among1.06~3.58, was inferior to Grade â…£standard. Similar to SFI trend of TN, Nemerow index showed fluctuated declining trendduring March to December. It illustrated that TN was the main factor that affectting waterquality of Dongchang Lake. This was consistent to the trend of water quality in interannualand seasonal analysis. Compared to four monitoring sites, the water quality of DongguanBridge was worse than that of other monitoring sites. (5) Water of four monitoring sites all eutrophicated during2004~2012. It took on afluctuating downward trend. Eutrophication index was higher in summer, especially in July.Moreover, the water eutrophication in Dongguan Bridge was the most serious, thenBeiguan Bridge, Nanguan and Xiguan Bridge presented lower degree of eutrophication.(6) The SFI of main priority pollutants, such as volatile phenol, cyanide, As, Pb,Cr(â…¥) and Cd in six districts were less than0.8during2001~2011, superior to Grade â…£standard. The SFI of petroleum compounds displayed a fluctuating upward trend, but theSFI value was nearly less than0.6except for1#district in2008. From the view ofcomprehensive pollution of all priority pollutants, the Nemerow index of all districts wasalmost less than1during2001~2011except for1#district in2008(about1.04). Petroleumcompounds played more negative effect on Dongchang Lake than other priority pollutants.(7) Based on analysis and assessment results of pollution status and water quality forDongchang Lake, in the light of environmental management status and main problems inexploitation, some countermeasures and suggestions of controlling water pollution andstrengthening water environment protection on Dongchang Lake were put forward in theview of controlling pollution sources, government management and public participation.