The Research On Analysis Of Trace Organic Pollutants In Water Bodies Based On Spectroscopy Techniques

Trace organic pollutants in water bodies are bio-refractory and highly toxic.The analysis techniques based on chromatography-mass spectrometry are time-consuming and expensive.Therefore,they are incapable of performing rapid and routine monitoring of trace organic pollutants in large scale.The spectroscopy techniques represented by fluorescence excitation-emission matrix（EEM）are simple,cheap,and sensitive.They have the potential as complementary analysis techniques for trace organic pollutants.Oils and antibiotics are typical trace organic pollutants,they are widespread in surface water and can pose significant ecological and health risks.However,the monitoring intensity is greatly limited due to the complicated testing requirements.To this end,fluorescence and UV absorption spectrum techniques were used in this study to investigate the source analysis technique for oil pollutants and the low-cost prediction technique for the concentration distribution of antibiotics,in order to provide monitoring technical support for the management and control of trace organic pollutants.The main results are as follows:（1）Source analysis of oil pollutants According to the composition of common oil pollutants in surface water,mixed samples of four major oil pollutants（gasoline,diesel,waste lubricant and vegetable oil）were prepared for spectral analysis.The results show that the intensities of UV absorption peaks(λ₂₆₈ nm andλ₂₇₉ nm)had good linear relationships with vegetable oil concentrations(R²_Adj.>0.98,p<0.01).It could be used as a rapid detection method for vegetable oils.However,the ordinary peak picking method of UV and fluorescence spectra was incapable of distinguishing petroleum pollutants.Fluorescence excitation-emission matrix coupled with parallel factor analysis（EEM-PARAFAC）were further employed to acquire characteristic fluorescence components of each oil.The simple or multiple linear fitting was conducted between fluorescence components and oil concentrations,and the oil analysis model was established,which could successfully analyze different oil sources and contribution ratios in the mixed oil system(R²_Adj.:0.65-0.99,p<0.01).It demonstrated the sensitive recognition of different aromatic compounds in oils by fluorescence characteristic peaks,and the potential to be applied to the rapid emergency monitoring of oil slick pollutants in water bodies.（2）Prediction of concentration distribution of antibiotics in water bodies Channels of central district of Ningbo were selected as research areas,the content of antibiotics in water bodies and the prediction performance of spectroscopy techniques were investigated.A total of 14 target antibiotics were detected in channels with a total amount of 1139.33 ng/L.Correlation analyses were performed between antibiotic concentrations and fluorescence components acquired by EEM-PARAFAC as well as water quality indices.The results show that terrestrial fluorescence components could be used to predict antibiotics dominated by non-point source inputs,conventional water quality indices could be used to predict antibiotics with both non-point source and sewage inputs（when the ratio of non-point sources is relative high）.On the other hand,protein-like fluorescence components could be used to predict antibiotics dominated by sewage inputs,and one of the protein-like components had a significant positive correlation with the total amount of antibiotics in channels,R²_Adj.=0.490,p<0.01,indicating that the protein-like fluorescence component could effectively predict the distribution of antibiotics in channels affected by domestic sewage.The fluorescence spectroscopy can establish the association between antibiotics and their sources,therefore it shows a good correlation,which has application potential for areas that cannot be covered by current monitoring capabilities.This study is based on the identification of the sources of trace organic pollutants using spectroscopy techniques.Which shows that through the analysis of the nature of pollution and the use of chemometric methods,a more precise prediction can be achieved.It provides an analytical idea for the management and control of massive and extensive trace organic pollutants.