Abstract:

29 systematic investigations on the Xuliujing water quality monitoring intersect in the Yangtze River estuarine were carried out from 2005 to 2012. We analyzed a 8year dataset of water quality conditions in the Yangtze River estuarine and the pollutant fluxes into the East China Sea. The annual concentration of the water quality and the pollutant fluxes were studied. It showed 2005,2010 and 2012 were floodflow period, 2006 and 2011 were dryflow period, the other 3 years were normalflow period. The range of annual average concentration of chemical oxygen demand (CODCr) was 0044-0098 mg/L, ammonia nitrogen (NH4N) was 0051-0358 mg/L, total phosphorus (TP) was 0069-0255 mg/L, active phosphate(PO4P) was 0044-0098 mg/L, Oil was 2367-7939 μg/L, copper (Cu) was 171-277 μg/L, cadmium (Cd) was 0057-0116 μg/L, arsenium (As) was 234-294 μg/L. A calculation method on Spearman rank correlation coefficient (Rs) was introduced. Using relativity analysis between water fluxes and time sequence, through this method, the evaluation on mutative trend of environmental quality could be automatically gotten, and the marked meaning was examined．The results indicated that the concentration of TP, PO4P, NH4N, Oil, CODCr in Xuliujing monitoring intersect of the Yangtze River increased and the concentration of TP increased significantly. The concentration of Cu, As, Cd decreased, and the concentration of Cu decreased significantly. During the 8 years, water quality of the Yangtze River was degraded. The rank of water quality at all monitoring sites were fromⅡto Ⅳgrade. The main pollutants were TP, NH3N and organic contaminants such as CODCr. The pollutant fluxes flowing into the East China Sea was increased significantly, which were mainly affected by the Yangtze River runoff and sometime were affected by the economic development in the watershed, for the annual average concentration of CODCr being the critical factor affecting the pollutant fluxes. The export fluxes of N in the Yangtze River estuarine increased according to several studies in recent 15 years.