Electrochemical Evaluation of Pollutants in the Environment: Interaction Between the Metal Ions Zn(II) and Cu(II) with the Fungicide Thiram in Billings Dam

Abstract

Pesticides are organic molecules used in the control of various pests in different crops. These molecules show functional groups that can interact with metal ions, forming new species with different properties. These new compounds have been attracting attention because they can become a new environmental problem. In this work the interaction of copper and zinc metal ions with Thiram pesticide was studied using electrochemical techniques. Studies in ultrapure water showed the formation of Zn−Thiram complex with reduction potential at −1.330 V; Cu−Thiram complex showed a cathodic peak at 0.020 V. Thiram causes a different effect on the two metal ions studied. It was observed that the ligand stabilizes more the Cu(II) than Zn(II). Both systems proved to be quasi‐reversible, controlled by the adsorption of the species on the electrode surface. The formation constants of the complexes were calculated to be 2.1×105 for Zn−Thiram and 1.5×1019 for Cu−Thiram. In the samples from Billings dam, the Zn‐complex showed reduction potential at −1.403 V; Cu‐complex exhibited a reduction peak at 0.012 V. Although there are interferers in river waters, the interaction of these metals with the pesticide showed high affinity, being possible to detect them in natural samples. The Cu(II) complex showed to be more stable in natural matrices when compared to the Zn(II) complex. The sensitivity for thiram electroanalytical determination decreases in the presence of Zn(II) and Cu(II).

Hysteresis of heavy metals uptake induced in Taraxacum officinale by thiuram

“…The latter is particularly toxic to soil biota. Furthermore, there are evidences that thiuram has the ability to complex metal ions in the soil environment 21 – 23 and affects heavy metals uptake by plants over the cultivation time. This problem is crucial for the consumers health and attracted concern of the European Commission which established maximum residue limits (MRLs) for common pesticides and heavy metals in either raw or processed food products 24 .…”

Electrochemistry Applied to the Evaluation of the Interaction between Coumarins and the Copper Metal Ion: An Experimental Study with a DFT-Based Analysis

“…Alternative methods for such studies are of great interest, so electroanalytical techniques emerge as a viable alternative for these studies, such as the cyclic voltammetry technique. [12][13][14][15][16][17][18] Nuñe-Dallos et al 19 used a modified coumarin-based electrode for Pb and Cd analysis, suggesting that the formation of the complex improved the electrochemical response of the metal ions. Ganjali et al 20 modified carbon paste electrode with a coumarin derivative for analysis of copper ions in water.…”