SEASONAL VARIATIONS IN TP,BOD_5 AND COD_(Mn) OF THEJINSHAJIANG RIVER,MINJIANG RIVER AND CHANGJIANG RIVER NEARBY YIBIN CITY
FU Jie-xiong1,2,3,ZHANG Xin-bao1,YAN Dong-chun1,2(1.Institute of Mountain Hazards and Environment,CAS,Chengdu 610041,China;2.Graduate School of the Chinese Academy of Sciences,Beijing 100039,China;3.Bureau of Environment Protection,Yibin 644000,China)
easonal variation characteristics and causations of main pollutants including TP,BOD5 and CODMn during the years from 2001 to 2005 in the surface water of the Minjiang River,Jinshajiang River and Changjiang River nearby Yibin City are reported in this paper.The results showed that seasonal variations in TP and BOD5 concentrations of the Minjiang River and Jinshajiang River showed no dissimilarity.The ratios of TP concentrations between flood season,normal water season and dry season were 1/0.74/0.43 and 1/0.59/0.73,respectively.The TP concentrations in flood seasons were greater than in normal water seasons and dry seasons,because of high concentrations of suspended sediment particles in flood seasons.The ratios of BOD5 concentrations between flood seasons,normal water seasons and dry seasons in the Jinshajiang River and Minjiang River were 1/0.84/1.45 and 1/1.30/3.38,respectively.The ratio of BOD5 concentrations between flood seasons and dry seasons was 3.38 in the Minjiang River,which is higher than that(1.45) in the Jinshajiang River,because of a huge amount of delivering pollutants from the Chengdu Plain in the middle and lower reaches of the Minjiang River between Leshan and Yibin.The higher BOD5 concentrations in flood seasons than in normal water seasons in the Jinshajiang River were attributed to the high concentrations of suspended sediment particles,which contain organic matter..Seasonal variations in CODMn concentrations of the Jinshajiang River and Minjiang River displayed different patterns.The ratios of CODMn concentrations between flood seasons,normal water seasons and dry seasons in the Jinshajiang River and Minjiang River were 1/0.74/0.43 and 1/0.74/1.08,respectively.Like the TP concentrations,seasonal variations in CODMn concentrations of the Jinshajiang River were caused by variations in the concentrations of suspended sediment particles.The higher CODMn concentrations in flood seasons were related to the higher concentrations of suspended sediment particles,those in dry seasons were related to severe water pollution.Finally,the concentrations of TP,BOD5 and CODMn at the Guagongshan monitoring section in Yibin were compared with those at the Zhutuo monitoring section at the entrance of the Three-Gorges Reservoir.The BOD5 concentrations at the Zhutuo monitoring section were higher than those at the Guagongshan monitoring section in Yibin,because a huge amount of pollutants was delivered into the Changjiang River from the Sichuan Basin through the Tuojiang River and other tributaries.
【CateGory Index】： P342
【CateGory Index】： P342