基于模糊理论的渤海湾海水水质综合评价

On assessing the water quality of Bohai Bay based on fuzzy math theory

综合评价渤海湾海水水质状况,分析主要水质影响因子。基于2001—2005年渤海湾海域20多个监测点的重金属、氮、磷、石油等10项污染物浓度监测数据,参照GB 3097—1997《海水水质标准》,采用模糊数学综合评价模型评价渤海湾水质污染程度。结果表明,渤海湾海水水质总体为《海水水质标准》中的3、4级,且主要污染物为无机氮。本文所采用方法强调主要污染因子对最终评价结果的影响,是比较严格的评价方法,因此其计算结果与内梅罗指数评价法同样偏保守。模糊综合评价模型可提供监测点水质对各级水质的隶属度,与内梅罗指数评价法相比,能为决策分析者提供更多有用信息,是更科学合理的评价方法。

This study intends to provide a scientific basis for effective pollution prevention and control of the seawater quality of Bohai Bay through analyzing the main factors influencing its quality. Based on the investigated data of concentrations over the ten pollutants from 2001 to 2005 from the 22 monitoring sites in the area in accordance of the GB 3097-1997 Seawater Quality Standard, we have done careful assessment of its quality by using the method of fuzzy mathematics, with the main influential factors of seawater pollution tested. Resuits of our assessments and measurements prove that, the seawater quality during the past five years on the whole belongs to the third and fourth grade in accordance with the GB 3097-1997 Seawater Quality Criteria. However, since the method used adopted mainly focuses on the influence of the key influencing pollution factors on the water quality, the model itself tends to be as strict and conservative as Nemerow index method. However, compared with Nemerow index method, the given model can provide each membership with the degree of the seawater quality at the monitoring site, it can provide the environmental decision-makers with more useful information, so it can be made to be a more scientific assessment method. During the past five years, it has been found that the inorganic nitrogen was the chief pollutant. Thus, the practical application of this model proves that the fuzzy comprehensive evaluation method here proposed is feasible for its purpose in seawater quality assessment as it could provide more valuable scientific results.