Fluorometry in application to fingerprint of petroleum products present in the natural waters

Abstract

Background: This study analyses the possibility of optical detection of trace amounts of oil in natural waters. Since petroleum and its derivatives induced by ultraviolet light exhibit a high intensity of fluorescence, this phenomenon can be used to detect petroleum products penetrating both the surface and subsurface waters. The challenge is to discriminate the fluorescence signal originating from petroleum substances from the total signal originating from both petroleum products and the natural substances. Results: Issues connected with fluorescence methods of detection of oil substances diffused in aquatic environment are analysed. Based on fluorescence spectroscopy, fluorometric indices of petroleum products for two forms (dissolved in n-hexane and dispersed in water) are discussed. The excitationemission spectra (EEMs) were determined in the range of excitation wavelengths 240-450 nm and 270-600 nm for emission. Selected parameters of oil fingerprinting are discussed: similarity ratio, intensity ratio and wavelength-independent fluorescence peaks (Ex max /Em max ). The latter was compared with the typical fluorescing natural marine residues. Conclusions: The results indicate that Ex max /Em max and intensity ratio appear to be efficient indices for the discrimination of oil pollution from autochthonous seawater fluorescent substances.

Microbubbles as Proxies for Oil Spill Delineation in Field Tests

“…Sonars have an advantage over point-based in-situ sensors when used to detect subsurface oil as they can cover a large continuous area as opposed to sampling a discrete volume of the water column [24]. Fluorometers, the most commonly used point-based in-situ oil sensors, are also susceptible to false positives due to disturbance from natural sources of fluorescence present in seawater [25]. In order to attain effective detection of oil in the water column, a combination of multiple methods employing different working principles are typically required.…”

Modelling the Visibility of Baltic-Type Crude Oil Emulsion Dispersed in the Southern Baltic Sea

“…The use of chemical substances that increase dispersion in the water column cannot be ruled out. Dispersed oil in the water column can also be detected by immersion oil sensors [13][14][15] and above-water sensors analysing the light coming out of the sea [16]. Moreover, the process of light transfer in the water column caused by oil dispersion in the water column causes oil to manifest itself by colour changes in the ocean and it is possible to determine whether these colour changes are caused by the presence of dispersed oil [17,18].…”

Synchronous fluorescence spectra of water contaminated by dispersed crude oil

“…The high sensitivity of fluorescence spectroscopy is the key to applying the method as a powerful tool to study the complex structure of petroleum products both in laboratory and in situ conditions. Fluorescence spectroscopy allows measurements to be performed in different methods used in stationary methods, such as fluorescence spectroscopy for single excitation wavelength (SWEx) or single emission wavelength (SWEm), excitation-emission spectroscopy (EEMs) [13][14][15] and synchronous fluorescence spectroscopy (SFS) [16,17] which was described by Lloyd [18] (and was used to study petroleum products [19], including directly in the marine environment [20]). The challenge for scientists is the possibility to monitor the spectroscopic transformations of petroleum products while in contact with the environment.…”