长江入海口徐六泾断面2005～2012年水环境因子及入海通量变化特征

分别于2005～2012年的4个季节对长江入海口徐六泾断面水质实施了29个航次的监测。2005、2010和2012年为丰水年，2006、2011年为枯水年，其余3 a为平水年。2005～2012年化学耗氧量（CODCr）的年度平均浓度范围为52～1469 mg/L，氨-氮（NH4 N）为0051～0358 mg/L，总磷（TP）为0069～0255 mg/L，活性磷酸盐（PO4 P）为0044～0098 mg/L，石油类（Oil）为2367～7939 μg/L，铜（Cu）为171～277 μg/L，镉（Cd）为0057～0116 μg/L，砷（As）为234～294 μg/L。引入计算Spearman秩相关系数的方法分析评价指标与时间序列间的相关性，并检验相关系数的显著性意义。评价结果显示，长江入海径流量呈现上升的趋势，但趋势不显著。年平均浓度呈上升趋势的污染因子水质要素从强到弱到小依次为TP、PO4 P、NH4 N、Oil和CODCr，TP上升趋势显著，呈下降趋势的水质要素从强到弱依次为Cu、As和Cd，Cu下降趋势显著；长江入海口的水质综合标准指数呈显著上升趋势，监测断面水质等级持续下降，污染状况持续恶化；长江污染物入海通量总体呈显著增加趋势，特别是氮的输出通量有较大增加。研究表明，长江入海口水质恶化速度加剧，应引起政府和社会的足够重视，保护长江水质刻不容缓

MUTATIVE TREND OF WATER QUALITY AT XULIUJING MONITORING INTERSECT ON YANGTZE RIVER AND THE POLLUTANTS FLUX FLOWING INTO THE SEA DURING 2005-2012

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.