大亚湾海域水质变化趋势及成因分析

Tendency and Causes Analysis of Marine Water Quality of Daya Bay

文章在收集1992～2009年大亚湾海域水环境的9种主要污染指标监测数据的基础上,分析得到大亚湾海域水质时空的变化趋势,并分别从附近污染源的分布、该海湾的水交换能力两个角度对水质的变化趋势进行了成因分析。结果表明,历年水质保持在一个较稳定的水平,并没有伴随污染排放量的增长而呈现上升的趋势,这是因为大亚湾较强的水交换能力,使得污染物排入后有较强的稀释扩散作用,浓度降低,即使污染源的排放有上升的趋势,水质仍然可以保持较稳定的水平;水质在空间上呈现较大的差异,这既与附近污染源的排放量有关,还与各分区的水交换能力有关。虽然大亚湾水质总体情况较好,但某些区域已受到了污染,并趋于恶化,因此,要改善大亚湾海域的水环境质量,必须在了解其水交换能力机制的基础上,控制各污染源的排放量。

Base on the monitoring data of 9 major pollutants of Daya Bay from 1992 to 2009,this article analyzed the spatial and temporal trends of marine water quality of Daya Bay,and discussed the causes from two aspects: the distribution of the nearby pollution sources and the water exchange capacity.Results showed that the water quality over the years maintained at a stable level,and didn't grow with the pollution emissions,which was found owning to the strong water exchange capacity of Daya Bay,pollutants poured into the bay were quickly diluted and diffused and the water quality kept stable although the sources were on the rise.The water quality of different areas showed large diversity,some regions were good,while some were contaminated and worsening,which was related to the distribution of the pollution sources and the different water exchange capacity of each area.