不同方法评价深圳湾富营养化问题的研究

Study on the evaluation of eutrophication in Shenzhen Bay by differentmethods

首先运用单因子指数法评价深圳湾氮磷污染程度,结果表明,以三类海水水质标准为基准,所有监测站点的PIDIN和PIDIP几乎都大于1,显然各个站点的DIN和DIP均超过三类海水水质标准,且各个监测站点的PIDIN和PIDIP平均值都呈现出外湾向内湾逐渐增大的趋势,可以看出深圳湾氮磷污染呈现外湾向内湾逐渐加重的趋势。再运用富营养化指数法、潜在性富营养化评价模式及营养状态质量指数法对深圳湾富营养化程度进行评价,结果表明所有监测点的E值都大于1,NQI均大于3,显然所有监测站点均呈现富营养化状态,且各个监测点的E值和NQI几乎都呈现外湾向内湾逐渐增大的趋势,表明深圳湾富营养化程度呈现外湾向内湾逐渐加重的趋势。最后运用模型模拟深圳湾丰枯水期富营养化程度,并用营养状态质量指数法计算模型结果,结果显示所有区域NQI均大于3,表明不管枯水期还是丰水期,深圳湾基本处于富营养化状态。枯水期NQI最大值为22,最小值为3;丰水期NQI最大值为23,最小值为4,表明丰水期深圳湾的富营养化程度较枯水期更为严重;不管枯水期还是丰水期,外湾的NQI基本在5左右,而内湾NQI基本都大于外湾,因此内湾的富营养化程度较外湾更为严重;枯水期涨潮时NQI最大值为22,落潮时NQI最大值为21;丰水期涨潮时NQI最大值为23,落潮时NQI最大值为22,因此涨潮时深圳湾的富营养化程度较落潮时更为严重。所有结果均表明深圳湾已呈现富营养化状态,因此治理深圳湾富营养化问题刻不容缓。

The single factor index method was used to evaluate the pollution degree of nitrogen and phosphorus in Shenzhen Bay.The results show that with the class Ⅲ standard of sea water quality standard,the PIDIN and PIDIP of all monitoring stations are almost greater than 1.Obviously,the DIN and DIP of each station exceed the class Ⅲ standard of sea water quality standard,and the average values of PIDIN and PIDIP of each monitoring station show the trend of increasing gradually from outer bay to inner bay.It can be seen that the nitrogen and phosphorus pollution in Shenzhen Bay shows the trend of increasing gradually from outer bay to inner bay.The eutrophication index method,potential eutrophication assessment model and nutritional quality index method were used to evaluate the eutrophication degree of Shenzhen Bay.The results showed that the E of all monitoring points were greater than 1,and the NQI was greater than 3.Obviously,all monitoring stations were eutrophication,and the E and NQI of each monitoring point showed a tendency of gradually increasing from the outer bay to the inner bay,indicating that the eutrophication degree of the Shenzhen bay showed a trend of gradually increasingfrom the outer bay to the inner bay. Finally, the model was used to simulate the degree of eutrophication in the Shenzhen Bayduring the high-water period and low-water period, and the model results were calculated using the nutritional quality indexmethod. The results show that the NQI is greater than 3 in the bay, indicating that the Shenzhen Bay is basically in the stateof eutrophication regardless of the dry season or the rainy season. The maximum NQI during the dry season is 22 and theminimum is 3;the maximum NQI during the rainy season is 23 and the minimum is 4, which indicates that the eutrophicationof Shenzhen Bay during the high-water season is more severe than that during the dry season. Regardless of the dry season orthe rainy season, the NQI of the outer bay is basically around 5, and the NQI of the inner bay is basically larger than that ofthe outer bay. Therefore, the eutrophication of the inner bay is more severe than that of the outer bay. The maximum NQI is22 in the high tide during the dry season, and the maximum NQI is 21 in the ebb;the maximum NQI is 23 in the high tideduring the rainy season, and the maximum NQI is 22 in the ebb, so the eutrophication of Shenzhen Bay is more serious thanthe ebb in the high tide. All the results indicate that the Shenzhen Bay has already become eutrophic, so it is urgent to tacklethe problem of eutrophication in Shenzhen Bay.