东平湖CDOM的光谱吸收特征及环境指示意义

随着南水北调东线工程的开通，东平湖作为山东段的两大调蓄湖泊之一，其水质的有效监测和污染预警显得尤为重要。根据东平湖夏季有色可溶性有机物(CDOM)吸收系数的空间分布特征和CDOM光学参数，探讨了CDOM吸收系数与溶解性有机碳(DOC)、叶绿素(Chla)等水质指标之间的关系，以期为今后建立水源水质突变的实时监控和污染事件预警系统提供依据。结果表明, 东平湖属于中-富营养型湖泊, CDOM吸收系数(a(280)，a(350)，a(440))均值分别为(12.90±1.17)，(3.11±0.40)和(0.65±0.09) m-1, 在一定程度上反映了湖泊的营养状况。东平湖内CDOM浓度整体呈现出从东岸河口区向湖心区、西南岸递减的趋势, 体现了河流陆源输入对东平湖CDOM的重要贡献。东平湖水体的CDOM浓度(如a(440))可以用来估算反演常规水质参数, 但仍需要进一步对不同季节不同水域CDOM的物质构成进行深入分析和研究。由吸收特征值S值、E₃/E₄、M值得出, 东平湖河口区输入的陆源CDOM进入湖泊后, 随着陆源输入的比例下降CDOM腐殖化程度降低, 富里酸的相对含量升高, 且相对分子质量也逐渐减小。

Absorption Characteristics and Environmental Significance of Dissolved Organic Matter in Lake Dongping

As an important water source in Shandong Province,Lake Dongping is one of the most important inland lakes to South-to-North Water Diversion East Route Proj ect.We tried to provide the basis for real-time monitoring of water quality mu-tation by using CDOM absorption characteristics.The average values of CDOM absorption coefficients [a(280),a(350),a (440)]were (12.90±1.17),(3.11±0.40)and (0.65±0.09)m-1 .a(440)had linear relationships with total nitrogen (p<0.01),total phosphorus (p<0.001),dissolved organic carbon (p<0.001),chemical oxygen demand (p<0.001),Chlorophyll a (p<0.001),which can be used to estimate the water quality parameters.The results showed that CDOM absorption coeffi-cient reflects the nutritional status of Lake Dongping,which is close to eutrophication level.There was an obvious decrease of CDOM absorption coefficients from river mouth of Dawen River to lake center and then to the outlets of lake.This illustrated that terrestrial input is the main source of nutrients and pollutants in Lake Dongping.