Photodegradation of chromophoric dissolved organic matters in the water of Lake Dianchi, China  

作　　者：Yuan ZHANG 

机构地区：[1]State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China [2]Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, B eijing 100012, China

出　　处：《Frontiers of Environmental Science & Engineering》2015年第4期575-582,共8页环境科学与工程前沿（英文）

摘　　要：Water samples were taken from Lake Dianchi, on the Yungui Plateau of southwest China, and experi- ments were conducted to simulate the photochemical degradation characteristic of chromophoric dissolved organic matter （CDOM） in the lake water. Three groups of experiments under different light conditions： ultraviolet （UV） light, visible light, and dark, were done and variations of fluorescence properties, UV absorbance, and dissolved organic carbon （DOC） concentrations during the experiments were analyzed to study the photodegradation process of CDOM with time. The result showed that light irradiation led to significant photochemical degradation of CDOM, resulting in changes in florescent properties, absorbance losses, decreases in aromaticity and average molecular weight, as well as decline in DOC concentration in the water. It was also observed that UV irradiation had greater effect than visible light did. However, various fluorophores had different sensitivities to the same irradiation condition, that is, protein-like fluorophore at the low excitation wavelengths is more sensitive to UV irradiation than the other fluorophores, and is more readily to undergo photo-degradation. In addition, visible light irradiation did not have significant impact on DOC in the water, with DOC concentration decrease by 5.57% -59.9% during the experiment time. These results may provide new knowledge on the environment behavior of CDOM in the water of Lake Dianchi.Water samples were taken from Lake Dianchi, on the Yungui Plateau of southwest China, and experi- ments were conducted to simulate the photochemical degradation characteristic of chromophoric dissolved organic matter （CDOM） in the lake water. Three groups of experiments under different light conditions： ultraviolet （UV） light, visible light, and dark, were done and variations of fluorescence properties, UV absorbance, and dissolved organic carbon （DOC） concentrations during the experiments were analyzed to study the photodegradation process of CDOM with time. The result showed that light irradiation led to significant photochemical degradation of CDOM, resulting in changes in florescent properties, absorbance losses, decreases in aromaticity and average molecular weight, as well as decline in DOC concentration in the water. It was also observed that UV irradiation had greater effect than visible light did. However, various fluorophores had different sensitivities to the same irradiation condition, that is, protein-like fluorophore at the low excitation wavelengths is more sensitive to UV irradiation than the other fluorophores, and is more readily to undergo photo-degradation. In addition, visible light irradiation did not have significant impact on DOC in the water, with DOC concentration decrease by 5.57% -59.9% during the experiment time. These results may provide new knowledge on the environment behavior of CDOM in the water of Lake Dianchi.

关 键 词：chromophoric dissolved organic matter photodegradation ultraviolet radiation dissolved organic carbon 

分 类 号：X703[环境科学与工程—环境工程] P617[天文地球—矿床学]