长江口污染物累积运移规律的初步研究

Preliminary Study on the Accumulation and Transport of Pollutants in Yangtze River Estuary

对长江口九段沙和崇明东滩潮滩水体及表层沉积物进行分析,结果表明:①南槽水体受到近岸排污的影响,在近岸形成NH4+-N和溶解态总磷(STP)含量很高的污染带,是远岸水域的2～3倍;悬浮颗粒吸附态磷(PP)作为P的主要形态,随着SS的增加,占总磷(TP)的比例从45%左右增加到90%左右。②南槽水体的总重金属分布态势主要取决于水体中SS的浓度,各元素之间及其各元素和SS相关性显著,主要吸附于SS中。③九段沙和崇明东滩在高低潮时受到不同水体的控制,低潮水体中重金属、TP和KN含量是高潮水体1 3～24 7倍,崇明东滩比九段沙变化更加显著。④受排污和水动力作用影响,低潮时悬浮物中重金属含量高于高潮时;悬浮物中重金属含量高于表层沉积物;高潮滩沉积物重金属含量高于低潮滩。

Both the water and sediments of the tidal flats of the Jiuduansha Shoal and the Chongming Island of the Yangtze River estuary were studied.The results are as follows:①The contents of NH_4^+-N and soluble total phosphorus(STP) in alongshore water of the South Groove are 1～2 times higher than in offshore water due to alongshore wastewater discharges.Being the dominant form of phosphorus,particulate phosphorus(PP) in the water makes up from about 45% to 90% of total phosphorus(TP) with the increase of suspended solids(SS).②The contents of heavy metals in the water of the South Groove are deeply affected by SS content.Significant positive correlation is found between heavy metals and SS,indicating that heavy metals are mainly adsorbed by SS.③The contents of heavy metals,TP and Kjeldahl nitrogen(KN) in the ebb tides nearby the Jiuduansha Shoal and the Chongming Island are 0.3～23.7 times higher than those in the flood tides,because of the different sources of water during the flood and ebb tides.The variation is even more obvious in the Chongming Island than in the Jiuduansha Shoal.④The contents of heavy metals in SS are higher than those in surface sediments.The contents of heavy metals in the surface sediments of high flat are higher than those of low flat.This pattern is mainly caused by direct discharge of sewage and tidal hydrodynamic action.