Monitoring of Dissolved Organic Matter in Aquatic Systems
High-resolution spatial and temporal monitoring of water resources is of growing interest to the scientific community, public authorities, and citizens, as it is essential for understanding the impacts of anthropogenic pressures and climate change. Off-the-shelf sensors currently fail to meet these needs, both in terms of the number of measurable parameters and the frequency or spatial coverage of measurements.
Dissolved Organic Matter (DOM) plays a key role in the global carbon cycle and influences water quality, phytoplankton productivity, and fish populations. It is also a crucial parameter for drinking water production due to its reactivity with oxidizing agents (particularly chlorine), which leads to the formation of carcinogenic halogenated by-products such as trihalomethanes (THMs). In addition, DOM contributes to the transport of metals, notably aluminum.
DOM characterization relies on a range of more or less sophisticated methods. While advanced techniques such as NMR or high-resolution mass spectrometry are limited to laboratory use, other approaches can be applied both in the lab and in the field. Current standard methods are based on sample collection, transport, and lab analysis using UV-VIS and fluorescence spectroscopy. A few commercial in-situ systems exist but remain prohibitively expensive (typically > €20,000).
The objective here is to develop a new generation of low-cost, easy-to-use, and deployable instruments, leveraging recent advances in low-power and connected technologies, and capable of high-frequency measurements.
The UV absorption and spectroscopy probe for DOM monitoring developed within the TERRA FORMA project builds upon instrumentation research conducted at LRGP, which previously led to the design of a portable kit for measuring physico-chemical parameters in aquatic systems. The goal is to develop a UV-VIS and fluorescence spectrometer adapted for in-situ use, either through integrated chip-scale spectrometers or via discrete measurements using arrays of LEDs, optical filters, and photodetectors targeting specific wavelengths of interest. This approach will be applied to DOM characterization and the detection of different phytoplankton groups.
Themes : Water Resources, Pollution
- Helms J.R., Stubbins A., Perdue E.M., Green N.W., Chen H., Mopper K. (2013) Photochemical bleaching of oceanic dissolved organic matter and its effect on absorption spectral slope and fluorescence. Mar. Chem. 155 : 81–91.
- Huguet A., Vacher L., Relexans S., Saubusse S., Froidefond J.M., Parlanti E. (2009) Properties of fluorescent dissolved organic matter in the Gironde Estuary. Organic Geochemistry 40 : 706–719
- Mrkva, M. (1975) Automatic u.v.-control system for relative evaluation of organic water pollution. Water Research, 9, 587-589.
- McKnight D., Boyer E.W., Westerhoff P.K., Doran P.T., Kulbe T., Andersen D.T. (2001) Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity. Limnol. Oceanogr., 46(1):38–48.
- Pons M.N., Assaad A., Oucacha C., Pontvianne S., Pollier B., Wagner P., Legout A., Guérold F. (2017) Nitrates monitoring by UV-vis spectral analysis, Ecohydrology & Hydrobiology, 17 : 46-52
- Poulain, A., Rochez, G., Van Roy, JP. et al. A compact field fluorometer and its application to dye tracing in karst environments. Hydrogeol J 25, 1517–1524 (2017). https://doi.org/10.1007/s10040-017-1577-1
- Zolnay Á. (2003) Dissolved organic matter : artefacts, definitions and functions. Geoderma, 113 : 187-209.
Updated on 21 juin 2025
