Temporaland Spatial Variation of Carbon,Nitrogen and Phosphorus in Wujiang River

According to the survey conducted from 2008,the spatial and temporal distribution characteristics of carbon,nitrogen and phosphorus in the water of Wujiang River were studied.Our results showed that the mean value of TN was 2.317 mg/L,while the inorganic nitrogen was 2.107 mg/L.The proportions of inorganic nitrogen in TN and NO₃^--N in inorganic nitrogen were 90.93% and 95.97%,respectively,indicating that inorganic nitrogen was the major nitrogen pollution components in the water systems.The annual average concentration of TP in the Wujiang River water was 0.173 mg/L.At the same time,the single peak pattern was observed in the seasonal dynamics of TN and TP,and reached the maximum in flood period and summer,respectively.The particulate content of COD_Mn in the Wujiang River also showed significantly seasonal dynamics and reached the maximum in flood period.However,there was no vertical spatial heterogeneity for C,N and P as well as TN and TP in the Wujiang River water.The annual mean concentrations of NH₄⁺-N showed the highest value in Wanmu,followed byLujiao,Luoyingduan,and Wulong,indicating that the concentrations of NH₄⁺-N decreased from the upper reaches to lower reaches of the Wujiang River.However,the annual mean concentration of NH₄⁺-N in water was higher in Mazui than in Wulong,which was related to backwater of the Yangtze River.