汕头港水质的模糊综合评价

A comprehensive assessment of seawater quality at Shantou Port by fuzzy mathematical model

根据2009年4月至2010年3月对汕头港6个断面的连续调查所得数据,以溶解无机氮(DIN)、活性磷酸盐(PO4–P)、溶解氧(DO)、化学需氧量(COD)、硫化物和悬浮物作为海水水质评价指标,应用模糊综合评价法与多元尺度分析法对汕头港水质的时空变化进行评价。结果表明,汕头港全年各断面水质均为Ⅳ类,主要污染因子均是DIN和PO4–P。空间上,海湾西部污染程度明显比东部严重,尤其是西港河口因水动力学条件差污染最为严重。时间上,水质变化无明显季节性变化特征,其中,4月、5月与7月这三个月的水质明显好其他各月。汕头港水质与盐度呈明显的正相关(r=0.644)表明径流输入是汕头港主要污染来源。

Using survey data collected from a successive investigation into the 6 sections of Shantou Port from April 2009 to March 2010, this essay attempts to assess the spatial and temporal distribution and changes of the seawater quality along Shantou Port, with dissolved inorganic nitrogen （DIN）, phosphate, dissolved oxygen （DO）, chemical oxygen demand （COD）, sulfide and suspended matter as the assessment parameters, and fuzzy mathematical model coupled with multidimensional scaling as the research method. The results show that the seawater quality in each section and month is the Level IV by Chinese Marine Water Quality Standard （GB 3097--1997）, and that DIN and phosphate are the major pollutants. In spatial distribution, the water to the west of the bay is more severely polluted than that to the east, especially the zone around Xigang Estuary is the worst because of its poor hydrodynamic condition. In temporal distribution, the seawater quality manifests no significant seasonal differences, and the water quality in April, May and July is distinctly better than the others. The significant positive correction（r=0.644） between seawater quality and salinity indicates that runoff is mainly pollution source.