Time-space Variation Characteristics of Waters Eutrophication in Malodorous Yuxi River
The time-space variation characteristics of waters eutrophication in Yuxi River were investigated with the evaluating comprehensive eutrophication state index of total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH3-N), chemical oxygen demand (COD), biochemical oxygen demand (BOD5) of February (dry season) and October (rain season) in 2014.Results showed that Yuxi River was in serious eutrophic state, which was at Grade Ⅴ or interior to Grade Ⅴ.TP, TN, COD, BOD5 and NH3-N had obvious seasonal difference;their concentrations in dry season were higher than in rain season.Changes along the river of water quality declined after rising.The study suggested that pollutants such as agricultural wastewater, sewage and industrial wastewater, rain water runoff, pipeline and infiltration water all make for quite a toxic river.