Changes in Fluorescence of Aquatic Dissolved Organic Matter Induced by Plastic Debris

Water contamination with plastic materials represents one of the most pressing environmental problems that the modern world is facing. In this context, the present paper aims to investigate the influence of fluorescent dissolved organic matter (FDOM) released by plastic materials on the aquatic bacterial fraction and evaluate the efficiency of fluorescence spectroscopy in identifying plastic FDOM in freshwater. To this purpose, river and tap water samples were contaminated in a controlled manner in the laboratory, and the water quality parameters and bacterial occurrence for these samples were determined using standard physico-chemical characterization methods: fluorescence spectroscopy, dynamic light scattering, and flow cytometry. The results revealed that plastic debris influenced the dissolved-particulate organic matter continuum, also affecting bacterial cell proliferation in both the river and tap samples. The study highlights that the impact of plastic FDOM on bacterial proliferation should not be taken lightly, while fluorescence spectroscopy proved to be an effective method for identifying the presence of plastic FDOM in water samples of various origins.