Towards a novel class of photoacoustics-based water contamination sensors
Maciej Grzegorczyk, Stanisław Pogorzelski, Paweł Rochowski
Abstract
The aim of the research was to demonstrate the potential and operational novelty of the photoacoustics-based techniques for sensing and quantitative characterization of complex chemicals, plastics and photosynthetically-active biological contamination species occurring in natural water bodies. Apart from a standard photoacoustic spectroscopy approach (PA), an alternative methodology based on the diffusive reflectance mode (DR) was used to study a variety of model pollution samples, including chemical contaminants, plastics suspension, and green algae cultures suspended in Baltic sea waters. It was found, that the PA method offers a higher spectral resolution compared to the DR results. On the other hand, due to the modality-specific various efficiency of the light-matter interactions, these two techniques may provide distinctly-different spectral signatures of contamination stressors in complex, multicomponent natural systems. In particular, the DR method appeared to provide a higher contrast between microplastics and natural biota components compared to the PA results. Bearing in mind the importance of the already introduced and photoacoustically obtainable environmental pollution bioindicator i.e., the energy storage parameter of photosynthetically-active species, the combination of the PA and DR techniques is supposed to provide a promising starting point towards designing a novel class of photoacoustics-based water contamination sensors.