基于有色溶解性有机质(CDOM)解析陆源污染物在东海区域的分布特征

Characterization of terrestrial pollutants in the East China Sea based on chromophoric dissolved organic matter (CDOM)

随着"陆海统筹"海洋保护战略的提出,近海水质修复越来越依靠对污染源数据的准确掌握,而活性磷酸盐和总无机氮等常规水质指标不能对海洋中陆源污染物进行有效指示.因此,本研究利用三维荧光光谱结合平行因子分析(EEM-PARAFAC)等技术分析了象山港和东海不同深度有色溶解性有机质(CDOM)的组成和分布特征,探讨基于CDOM快速分析技术的近海水质评价方法.结果表明,象山港水质受沿岸排放影响显著,其氮磷营养盐、陆源腐殖质(EEM-PARAFAC组分C1和C4)和生活源类蛋白质(C3和C5)物质显著高于东海表层水体.在东海水体中,5个荧光组分的高值区主要分布在北部近岸表层海域,与盐度分布相反,清晰表明长江冲淡水等陆源输入对CDOM的显著影响.相关性分析表明,陆源物质输入是东海表层水体中污染物的重要来源,而底层污染物的来源则更为复杂.总体上,污水类物质较大程度地改变了东海北部表层CDOM的组成.本研究表明,利用EEM-PARAFAC等技术可快速有效地识别海洋中CDOM的来源,深刻揭示了陆源排放对海洋水质的影响程度,可为"陆海统筹"海洋保护策略提供技术支撑.

With the proposal of "land-sea coordination" marine conservation strategy, the accurate source data of pollutants are increasingly required for the restoration of offshore water quality, but general water quality indices such as active phosphate and total inorganic nitrogen show insufficient indication on terrestrial pollutants in marine environment. To this end, the composition and distribution characteristics of chromophoric dissolved organic matter(CDOM) at different depths in the Xiangshan Bay and the East China Sea were analyzed by the techniques such as the three-dimensional fluorescence spectrum combined with parallel factor analysis(EEM-PARAFAC), and the coastal water quality by the data derived from the rapid CDOM analysis were further evaluated. Results show that the water quality of Xiangshan Bay is significantly influenced by coastal discharge, and its nutrients, terrestrial humic-like substances(EEM-PARAFAC components C1 and C4), and anthropogenic protein-like substances(C3 and C5) are significantly higher than the surface water of the East China Sea. In the East China Sea, the high values of the five fluorescence components are mainly distributed in the surface water of the northern offshore region, showing that the Yangtze River and other terrestrial inputs have a significant impact on the CDOM. A correlation analysis shows that the terrestrial input is an important source of pollutants for the surface water of the East China Sea, but the sources of bottom pollutants are more complex. Overall, sewage-like pollutants significantly change the composition of surface CDOM in the northern East China Sea. This study shows that techniques such as the EEM-PARAFAC can quickly and effectively identify the sources of CDOM in the sea water, revealing the impact of terrestrial discharge on sea water quality and providing technical support for the marine conservation strategy.