College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China.
Int J Environ Res Public Health. 2022 Oct 11;19(20):13055. doi: 10.3390/ijerph192013055.
The eutrophication of coastal water has been a critical environmental problem in China's offshore areas. How to effectively assess the status of coastal waters is key for pollution treatment and environmental protection. In recent years, eutrophication-symptom-based and multi-indicator methods, termed "phase II" methods, have been gradually adopted to assess the eutrophication status in some coastal waters in China and have achieved success. The cumulative quantile is typically selected to determine the characteristic value of an indicator in "phase II" methods. The influence of small-scale damaged water bodies on eutrophication assessment may be exaggerated, which often leads to the overassessment of the eutrophication status. In this study, the area ratio method was integrated into the assessment of the estuarine trophic status (ASSETS) method in order to assess the eutrophication status of Xiamen Bay in 2016. The results indicated that, in 2016, the eutrophication status of Xiamen Bay coastal waters was moderate and exhibited spatiotemporal variation. The area ratio method can effectively reduce the effect of small-scale coastal waters with extremely high eutrophication on the overassessment of eutrophication at the broader scale, allowing the eutrophication status to be better reflected, even with limited observation data. The centralized distribution of pollution sources and poor hydrodynamic conditions are the main reasons for the aforementioned phenomenon. Controlling the pollution discharge from the Jiulong River in flood seasons is key to reducing eutrophication in Xiamen coastal waters.
中国近海海域富营养化问题一直较为突出，如何有效评价近岸海域水质状况，是开展污染治理和环境保护的关键。近年来，中国部分近岸海域已逐步采用富营养化症状指标法和多指标法等“二期”方法进行富营养化评价，并取得了较好的效果。“二期”方法中通常采用累积分位数法确定指标的特征值，这可能会夸大小尺度受损水体对富营养化评价的影响，导致富营养化状况的高估。本研究将面积比值法引入到港湾水质类别评价（ASSETS）方法中，以评价 2016 年厦门海域的富营养化状况。结果表明，2016 年厦门近岸海域整体处于中营养状态，且存在时空差异。面积比值法可以有效减少小尺度极高富营养化水体对大尺度富营养化程度的高估影响，使富营养化状况得到更好的反映，即使在观测数据有限的情况下也是如此。污染集中排放和水动力条件较差是造成这种现象的主要原因。控制九龙江在丰水期的污染排放是降低厦门近岸海域富营养化的关键。
