Natural fluorescence of organic matter excitation-emission matrix (EEM) and 2D spectas at 254 nm excitation wavelength of underground water from Fontaine de Vaucluse system (2020 to 2021)

Raw excitation-emission matrix (EEM) and 2D emission spectra at 254nm excitation wavelength obtained from spectrofluorometer SHIMADZU RF-5301 PC (150 W xenon lamp) for several springs (fdV_emmah, Nesque_Bourget, Nesque_sources, Millet_EMMAH, St_Trinit_regard) and flows from the unsaturated zone (LSBB_Flow_A, LSBB_Flow_AC, LSBB_Flow_AJ, LSBB_Flow_AY , LSBB_Flow_B, LSBB_Flow_C, LSBB_Flow_D, LSBB_Flow_i, LSBB_Flow_W) of the Fontaine de Vaucluse system. Water was sampled from february 2020 to october 2021, and analyzed within three days. EEM was obtained with the following wavelength windows : λex= [220 ; 450] nm, interval=10 nm ; λem= [250 ; 550] nm, interval=1 nm, and 2D spectra at λex=254nm, λem= [250 ; 530] nm, interval=1 nm. The temperature was stabilized at 20°C in a bath with a thermostat. Slit-widths of 15 nm were used for the excitation and emission monochromators, with a fast default scan speed. The stability of the apparatus was checked based on the Raman peak on fresh MilliQ water excited at 348 nm. Raw EEM data needs to be corrected from scattering and from water molecule diffraction. For the last, a milliQ water sample was analysed with groundwater sample each day of analysis. These EEM are joined with groundwater ones. EEMs were corrected and processed by PARAFAC modeling to identify the different fluorescent organic compounds in the following publication: Serène, L., Batiot-Guilhe, C., Mazzilli, N., Emblanch, C., Babic, M., Dupont, J., Simler, R., Blanc, M., and Massonnat, G.: Transit Time index (TTi) as an adaptation of humification index to illustrate transit time differences in karst hydrosystems. Application to the karst springs of Fontaine de Vaucluse system (Southeastern France), Hydrol. Earth Syst. Sci. Discuss. [preprint], https://doi.org/10.5194/hess-2022-100.