选择长江口滨岸为典型研究区,分析探讨了排污活动对长江口滨岸潮滩营养盐环境地球化学过程的影响.结果表明,潮滩环境因子对排污活动有明显的环境响应.排污口滨岸潮滩上覆水、表层沉积物孔隙水和表层沉积物中的NH4^+-N,TIN,TDP,Ads-P,Fe-P和CFAP+Ca—P等都有显著富集效应,这不仅与排污直接贡献营养盐相关,而且与排污活动使环境因子发生变化进而影响营养盐的地球化学过程相联系;而NOx^-N在长江口滨岸潮滩上覆水、表层沉积物孔隙水和表层沉积物中并未出现累积高峰值,表明外源输入不是潮滩环境中NOx^-N主要来源.分析结果还显示,排污口潮滩沉积物-水界面间N、P分子扩散通量明显大于非排污口,反映排污活动不仅加剧营养盐N、P在潮滩环境中富集,而且还加剧了潮滩沉积物.水界面间营养盐的扩散过程.
Influences of sewage discharge on environmental geochemical processes of nutrients were investigated in the Yangtze estuarine and tidal flats. The result indicated that the environmental elements obviously responded to sewage discharging. There was obvious enrichment of NH4^+ -N,TIN, TDP, Ads-P, Fe-P and CFAP + Ca-P in overlying water, surface sediments and its pore waters adjacent to sewage outlets in the Yangtze Estuary. The enrichment of nutrients N and P was considered to be related not only to the inputs of nutrients from sewage outlets, but also to the changes of environmental factors induced by sewage discharge. On the contrary, there was no significant enrichment of NOx^- -N in the tidal water, pore waters and surface sediments from the Yangtze Estuary, which showed that external inputs of nutrients was not the primary factor controlling the distributions of NOx^--N. It was also shown that the diffusive fluxes of nutrients N and P across sediment-water interface was markedly higher at sewage outlets than the control sampling sites in tidal flats, indicating that sewage discharge not only increased the accumulation of nutrients N and P in the tidal flats, but also strengthened the exchange processed of nutrients across tidal sediment-water interface.