Chemical behavior of Cu, Zn, Cd, and Pb in a eutrophic reservoir: speciation and complexation capacity

Abstract

This research aimed at evaluating cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) speciation in water samples as well as determining water quality parameters (alkalinity, chlorophyll a, chloride, conductivity, dissolved organic carbon, dissolved oxygen, inorganic carbon, nitrate, pH, total suspended solids, and water temperature) in a eutrophic reservoir. This was performed through calculation of free metal ions using the chemical equilibrium software MINEQL+ 4.61, determination of labile, dissolved, and total metal concentrations via differential pulse anodic stripping voltammetry, and determination of complexed metal by the difference between the total concentration of dissolved and labile metal. Additionally, ligand complexation capacities (CC), such as the strength of the association of metals-ligands (logK'ML) and ligand concentrations (C L) were calculated via Ruzic's linearization method. Water samples were taken in winter and summer, and the results showed that for total and dissolved metals, Zn > Cu > Pb > Cd concentration. In general, higher concentrations of Cu and Zn remained complexed with the dissolved fraction, while Pb was mostly complexed with particulate materials. Chemical equilibrium modeling (MINEQL+) showed that Zn(2+) and Cd(2+) dominated the labile species, while Cu and Pb were complexed with carbonates. Zinc was a unique metal for which a direct relation between dissolved species with labile and complexed forms was obtained. The CC for ligands indicated a higher C L for Cu, followed by Pb, Zn, and Cd in decreasing amounts. Nevertheless, the strength of the association of all metals and their respective ligands was similar. Factor analysis with principal component analysis as the extraction procedure confirmed seasonal effects on water quality parameters and metal speciation. Total, dissolved, and complexed Cu and total, dissolved, complexed, and labile Pb species were all higher in winter, whereas in summer, Zn was mostly present in the complexed form. A high degree of deterioration of the reservoir was confirmed by the results of this study.

The effects of copper on photosynthesis and biomolecules yield in Chlorolobion braunii

“…These results indicate that even in concentrations as low as those found in the environment (Tonietto and Grassi , Tonietto et al. , Asare et al. ), microalgae can face difficulties, with the cell division process being impaired.…”

“…Natural dissolved organic materials present in freshwaters complexes copper (Buffle ), and in such waters, free copper ions are detected in the order of 10 −9 to 10 −7 mol · L −1 (Mansilla‐Rivera and Nriagu , Wang and Chakrabarti , Tonietto et al. ).…”

Differential blood counting in fish as a non-destructive biomarker of water contamination exposure

“…The concentration of dissolved oxygen in water could be used to determine water quality, since it directly affects aquatic biodiversity. Moreover, according to Valente, Padilha, andSilva (1997), Silv erio et al (2005), Zanata et al (2008), Rocha et al (2010), and Tonietto et al (2015), the water analysis revealed that Barra Bonita presents conditions that are unsuitable for aquatic life.…”

Glint Removal Assessment to Estimate the Remote Sensing Reflectance in Inland Waters with Widely Differing Optical Properties

“…The time residence of BB varies between 30 (summer) to 180 days (winter), whereas in the BAR it ranges between 7-24 days. Both reservoirs are considered eutrophic systems, with recurrent microalgae blooms due to nutrient and pollutant discharges within the Tietê River driven by nearby urban areas [21][22][23][24][25].…”