Continuous fluorescence excitation-emission matrix monitoring of river organic matter
Authors: Elfrida M. Carsteaa,*, Andy Bakerb, Magdalena Bierozac, Darren Reynoldsd
aNational Institute of R&D for Optoelectronics, INOE 2000, 409 Atomistilor Str., RO-077125 Magurele, Romania
bConnected Waters Initiative, University of New South Wales, Water Research Laboratory, 110 King St, Manly Vale, NSW 2093, Australia
cDepartment of Civil Engineering, Queen’s Building, University Walk, Bristol BS8 1TR, UK
dUniversity of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK
Summary
In this study, continuous fluorescence excitation-emission matrix obtained from the samples of a small urban river in Birmingham, UK (Bourn Brook River). The experiment was performed from August 4, 2009 to August 14, 2009 using a Varian Cary Eclipse spectrofluorometer that was adjusted in the mobile laboratory. During measurements, 2597 fluorescence excitation emission matrices were collected and humic and tryptophan like compounds was identified. A diesel event was also observed. Samples were filtered and tested.
For peak picking, self-organizing map was used. Real time monitoring of 11 days showed that the system, without a cleaning period of at least two weeks, can run continuously. Two major problems, biofilm growth and gradual increase of pH were encountered, otherwise, the system worked before power supply failure. Fluorescence peak picking method revealed that fluorescence of humic like peak was intense in the first few days of experimentation and were generated by rainfall events.
One event of diesel pollution was observed using fluorescence spectroscopy which overlapped with tryptophan like peak. But still, a separate unit was formed on self-organizing map. The study also shows that fluorescence monitoring of less than 30 minutes is suitable for dissolved organic matter variation assessment which also detected sewage or petroleum products.
A further investigation which can be made is to see how long can the system run continuously, in other words, how many observations can be made before significant fouling occurs.
Reviewer: Aamir Alaud-din
aamiralauddin@gist.ac.kr