长江入海口段水质荧光指纹特征解析

Analysis of Fluorescence Fingerprint Characteristics of Water Quality in the Estuary of the Yangtze River

水质荧光指纹技术是近年来新兴的水体污染检测技术,它可以展现水体有机物组成信息,弥补传统常规水质参数的不足。长江入海口段沿江地带是我国的产业密集带,区域内城市化程度高,工业发达,在此区域内,水环境质量变化会直接影响经济发展和民众身体健康,因此,研究长江入海口段的水质变化具有重要的意义。长江入海口段的pH、电导率、NH_(3)-N、COD_(Mn)、TP、TN和TOC等指标变化趋势不尽相同,但是从电导率、TN、COD_(Mn)、TOC这四个指标,反映出沿着长江入海口段从上游至下游的过程中具有一定的污染积累,尤其在下游的CJ-11和CJ-12采样点,可能受到了较大的污染源影响。从常规指标和TOC的结果并不能直接体现污染信息,只能反映污染总量从上游至下游的增加。长江入海口段水质荧光指纹主要包含三个荧光峰,记作峰A、峰B、峰C,它们的[激发波长,发射波长]分别为[275,335]nm,[230,345]nm和[250,450]nm,其中峰A和峰B荧光强度的变化趋势同步,相关性较高,相关系数为0.9948,表明两峰很可能来自相同污染源。通过水质荧光指纹比对,在长江入海口段CJ-11和CJ-12两点的水质荧光指纹与支流HPJ-1的水质荧光指纹相似度分别达到86%和88%,而与CJ-10的相似度<60%。由此可见,长江入海口段下游水质荧光指纹(CJ-11和CJ-12)发生变化,可能是由支流HPJ汇入长江入海口段造成的。支流HPJ的水质荧光指纹信号与印染行业水质荧光指纹数据库相似度约90%,表明支流HPJ的水质荧光指纹信号可能与当地的印染废水排放有关。基于长江入海口段峰A和峰B的强度与NH_(3)-N浓度呈现良好的线性正相关性(相关系数为0.8855),水质荧光指纹具有作为指示长江入海口段NH_(3)-N浓度的潜力。水质荧光指纹技术可以展现水体有机物质组成和来源,在污染示踪以及水质状况评价方面具有重要的应用价值。

The technique of aqueous fluorescence fingerprint is an emerging technology in water pollution detection in recent years,which can reveal the composition information of the water organic matter and make up for the shortcomings of conventional water quality parameters.The coastwise area of Yangtze River Estuary is an industry-intensive belt in China with high regional urbanization and developed industry.In this basin,water quality change would directly affect economic development and human health.Therefore,it is of great significance to study the water quality change in the Yangtze River Estuary.Different variation trends appeared among pH,conductivity,NH_(3)-N,COD_(Mn),TP,TN and TOC in the study area.However,the four indicators of conductivity,TN,CODMn and TOC,still reflected that there was a certain pollution accumulation from upstream to downstream along the estuary section of the Yangtze River,especially at the downstream sampling points CJ-11 and CJ-12,which may be greatly affected by pollution sources.The results of conventional indicators and TOC could not directly reflect the pollution information,but could only reflect the increase of total pollution from upstream to downstream.Aqueous fluorescence fingerprint in the estuary of the Yangtze River mainly contained three fluorescence peaks,which were recorded as peak A,peak B and peak C.The[excitation wavelength and emission wavelength]were[275,335]nm,[230,345]nm and[250,450]nm respectively.The synchronous variation trend of fluorescence intensity was between peak A and peak B with a high correlation,and the correlation coefficient reached 0.9948,indicating that the two peaks were likely to come from the same pollution source.Through the similarity comparison algorithm of aqueous fluorescence fingerprints,the similarity of aqueous fluorescence fingerprints between the sampling points of the Yangtze River estuary(CJ-11 and CJ-12)and tributary of the estuary(HPJ-1)were 86%and 88%,respectively.Meanwhile,the similarity to CJ-10 was all less than 60%.It indicated that the change of aqueous fluorescence fingerprints(CJ-11 and CJ-12)in the lower reaches of the Yangtze River Estuary might be caused by the tributary HPJ,which flows into the Yangtze River Estuary.The similarity between the aqueous fluorescence fingerprint of tributary HPJ and the fluorescence fingerprint database of the printing and dyeing industry was approximately 90%,illustrating that the aqueous fluorescence fingerprint of tributary HPJ might be related to the discharge of local printing and dyeing wastewater.Based on the terrific linear positive correlation between the peak intensity,including peak A and peak B,and the concentration of NH_(3)-N in the estuary of the Yangtze River(the correlation coefficient is 0.8855),the aqueous fluorescence fingerprint technique could have the potential to indicate the concentration of NH_(3)-N in the estuary of the Yangtze River.Aqueous fluorescence fingerprint technology could reveal the composition and source of organic matter in water and have important application value in pollution identification and water quality evaluation.