Novel method of removing metals from estuarine water using whole microbial mats

Abstract

This study addresses the limited understanding of chromium-microbial mat interactions in estuarine tidal fats. The aims were to evaluate (1) the efciency of the microbial consortium in Cr(III) removal from seawater; (2) the elemental and mineralogical composition of the microbial mat as a natural system in the Cr removal, (3) the efects of metalon microphytobenthos, and (4) possible interactions of Cr with other metals present in the consortium. Microbial mats were exposed to Cr(III) solutions at diferent concentrations (2–30 mg Cr/L). Analysis such as metal concentration, organic matter content, chlorophyll a and phaeopigment concentrations, abundance of diatoms and cyanobacteria, SEM-EDS, and XRD were performed. Most of the Cr(III) was deposited, as chromium oxide/hydroxide, on the surface of all microbial mat components. The complete microbial mat, comprising sediments, detritus, EPS, and diverse microorganism communities, exhibited a remarkable capacity to accumulate Cr(III), retaining over 87% in the solution.