Flow cytometric approach to evaluate the impact of hydro-technical concrete compounds’ release to the freshwater microbiome

The aim of this research was to test the potential of applying a flow cytometric procedure to evaluate the impact of concrete compounds’ release to the freshwater microbiome. Cells from the collected samples were stained with a fluorogenic redox indicator dye that measures the redox potential of microbial cells. This novel approach was combined with the assessment of microorganisms’ penetration into the internal structures of concrete using the Rose Bengal sodium salt staining. Rose Bengal staining revealed an intense fouling of the upper and side walls of the concrete cubes and also indicated the penetration of microorganisms inside the concrete as observed for the cubes’ cross-sections. Flow cytometric cellular redox potential measurement revealed high percentages of active cells within the concrete’s porous structures and in non-exposed water (32.7% and 30.2% of active cells) versus samples from exposed water and concrete’s outer surfaces (6.8%, 6.1%, and 3.3% of active cells). The results demonstrated a detrimental impact of hydro-technical concrete on the vitality of microbial cells within the freshwater environment. Tested protocol by analyzing the physiology of microbial cells improved the functional description of complex communities to evaluate the fate of contaminants present in the concrete-based hydro-technical infrastructure.