The extensive application of pesticides especially in farmland, water bodies including ground water and surface water might be polluted via leaching or overland flow. Besides this kind of traditional chemicals that may raise environmental concerns, a newly defined group of organic compounds that include pharmaceuticals and personal care products (PPCPs), endocrine disrupting compounds (EDCs) and disinfection byproducts (DBPs) has caused emerging concerns in the past decade due to their frequent presence and potential threat to both the environment and human health even present at pretty low oncentrations. One techniqual obstacle for the study on their fate and effects is their detection and determination. The commonly used instrument such as HPLC-MS and HPLC-MS/MS has a high cost and requirement of operational skills. Such difficulty hinders long-term termporal and special monitoring of these pollutants in wide area.
Prof. Xiangyu Tang of Institute of Mountain Hazards and Environment, Chinese Academy of Sciences (IMHE) and his team have been working on addressing the issues by means of in-situ monitoring of spectroscopy changes. Both UV absorbance and fluorescence are efficient in examining the engagement and transformation of chromophoric dissolved organic matter (CDOM) in virtually any reaction pertinent to water treatment. Compared with absorbance, use of fluorescence, particularly, three-dimensional excitation-emission matrix (EEM) offers several advantages and has several well resolved structures which can be used to provide, potentially in real time, fingerprint information about distinct CDOM fluorophores and their interactions with oxidants or halogenating agents.
The team has achieved preliminary research progress. They examined the formation of aldehydes and carboxylic acids, which are responsible for the undesirable odor and contribute to the biodegradable organics in waters, in ozonated surface water and municipal wastewater secondary effluent and addressed correlations between the generation of these compounds and concurrent changes of the fluorescence of CDOM substrates. The results demonstrate the feasibility of surrogate monitoring of the formation of biodegradable oxidation by-products via online measurements of water/wastewater EEM fluorescence.
Support for this work is provided by NSFC (41301549), and the research observation has been published in Chemosphere (Liu C, Tang XY, et al., 2015, doi: 10.1016/j.chemosphere.2014.12.054).