Contamination alters the physicochemical and textural characteristics of clays in the sediments of the peri urban Reconquista River, affecting the associated indigenous microorganisms

TUFO, ANA; VAZQUEZ, S.; GRIMOLIZZI, C.; PORZIONATO, N.; PRADOS, B.; SICA, M.; CURUTCHET, G.

Minerals

MDPI

Lugar: Basel; Año: 2021 vol. 11

The physicochemical and textural characteristics of river sediments and, essentially, their20 clays, are at the center of a network of biological and geochemical factors that affect and are21 reciprocally affectedmutually modifying. Therefore, the contamination, the characteristics of the22 clays and the associated microorganisms strongly influence each other. In this work, sediments23 from two sites of the urban Reconquista River, near Buenos Aires city, Argentina, exposed to24 different environmental contexts were characterized. The huge differences in the organic matter25 content in the vertical profile between both sediments strongly evidenced the polluted status of SF26 as opposed to DR site. The exhaustivethorough physicochemical and textural characterization of27 the sediments and their clay fraction mainly performed by, pH, ORP, spectrophotometry, XRD,28 laser diffraction, N2 adsorption-desorption isotherms, EDS and SEM measurements revealed thatorganic matter (DR: 41 ± 5 g kg-1; SF: 150 ± 30 g kg-1 29 ) intervenes in the retention of heavy metalslike(DR: 5.6 mg kg−1 Zn, 7 mg kg−1 Cu and, 3.1 kg−1 Cr,; SF: 240 mg kg−1 Zn, 60 mg kg−1 30 Cu, 270 mgkg−1 31 Cr), and affects the level of association and formation of mineral?organic aggregates (DR: 15 ±32 3 μm; SF: 23 ± 4 μm). This can be decisive in the surface interaction required for the establishment33 of bacterial assemblages, which determine the biogeochemical processes occurring in sediments34 and have a key role in the fate of contaminants in situ and in the remediation processes that need to35 be applied to restore the anoxic contaminated sediments.