Seasonal Variation of Dissolved Lead Speciation in Tagus Estuary, Portugal

2021 ◽  
Vol 20 (4) ◽  
Author(s):  
M. Praveen Kumar
Keyword(s):  
Binding Sites ◽  
Lead Concentration ◽  
Phytoplankton Bloom ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Quality Parameters ◽  
Lead Speciation ◽  
Major Cations ◽  
Similar Decrease

The behavior of lead species from Tagus estuarine water collected during winter (January), spring (April), and summer (June) seasons were evaluated. Water samples were titrated with Pb+2 followed by differential pulse anodic stripping voltammetry (DPASV). Experimental voltammetric values were interpreted assuming a macromolecular heterogeneous ligand described in a simple way by two types of binding sites, CL1 and CL2, where CL1 is related to stronger binding groups with lower concentration compared to CL2. Water quality parameters like dissolved organic matter (DOC), pH, salinity, temperature, and total lead concentration were measured during the period under study. The results pointed to a higher concentration of CL1 and CL2 sites in April probably due to the phytoplankton bloom. The decrease of KL1 with the increase of salinity from winter to summer may be caused by the increase of major cations (as Ca2+) in solution. The trend of KL2 followed the pH shift in all seasons since an increase of pH favors Pb2+ complexation with CL2 sites. Finally, the decrease of DOC in summer could be responsible for the decrease in the concentration of the different sites in solution from April to June, with a similar decrease of 35±3% for all of them.

scholarly journals Possibilities of electrochemical techniques in metallothionein and lead detection in fish tissues

2008 ◽  
Vol 52 (No. 5) ◽  
pp. 143-148 ◽  
Author(s):  
S. Křížková ◽  
O. Zítka ◽  
V. Adam ◽  
M. Beklová ◽  
A. Horna ◽  
...  
Keyword(s):  
Lead Concentration ◽  
Anodic Stripping Voltammetry ◽  
Electrochemical Techniques ◽  
Perca Fluviatilis ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Fresh Weight ◽  
Fish Tissues ◽  
Naturally Occurring ◽  
Lead Detection

In the present paper, we report on the use of adsorptive transfer stripping technique in connection with chronopotentiometric stripping analysis for metallothionein determination and of differential pulse anodic stripping voltammetry for lead detection in tissues of wild perch (<i>Perca fluviatilis</i>, <i>n</i> = 6) from the Svratka River in Brno, Czech Republic. Primarily, we determined the content of MT in tissues (muscles, gonads, liver and spleen) of perch. We measured the highest content of MT in spleen and liver (100&minus;350 ng MT per gram of fresh weight). We assume that the content of MT determined in perch tissues is probably related with the age of the fish and, therefore, with their exposition to heavy metals naturally occurring in the Svratka River. We detected a lead concentration in the tissues of one perch. It clearly follows from the results that the content of MT well correlates with the concentration of lead.

scholarly journals The effect of tamoxifen on the electrochemical behavior of Bi+3/Bi on the glassy carbon electrode and its determination via differential pulse anodic stripping voltammetry

2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Mehdi Jalali ◽  
Zeinab Deris Falahieh ◽  
Mohammad Alimoradi ◽  
Jalal Albadi ◽  
Ali Niazi
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Peak Height ◽  
Carbon Electrode

The electrochemical behavior of Bi+3 ions on the surface of a glassy carbon electrode, in acidic media and in the presence of tamoxifen, was investigated. Cyclic voltammetry, chronoamperometry, differential pulse voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy were used to find the probable mechanism contributing to the reduction of the peak height of bismuth oxidation with an increase in the concentration of tamoxifen. The obtained results show a slight interaction between the bismuth species and tamoxifen which co-deposit on the surface of glassy carbon electrode. Therefore, the reduction in the peak height of bismuth oxidation as a function of tamoxifen concentration was used to develop a new differential pulse anodic striping voltammetry method for determination of trace amount of tamoxifen. The effects of experimental parameters on the in situ DPASV of Bi+3 ions in the presence of tamoxifen shown the optimal conditions as: 2 mol L-1 H2SO4 (1% v v-1 MeOH), a deposition potential of -0.5 V, a deposition time of 60 s, and a glassy carbon electrode rotation rate of 300 rpm. The calibration curve was plotted in the range of 0.5 to 6 µg mL-1 and the limits of detection and quantitation were calculated to be 3.1 × 10-5 µg mL-1 and 1.0 × 10-4 µg mL-1, respectively. The mean, RSD, and relative bias for 0.5 µg mL-1 (n=5) were found to be 0.49 µg mL-1, 0.3%, and 2%, respectively. Finally, the proposed method was successfully used for the determination of tamoxifen in serum and pharmaceutical samples.

scholarly journals Thallium Associated with Manganese Ore Tailings in a Deactivated Mine in the Western Region of Bahia, Brazil

2021 ◽  
Author(s):  
Jorge Luís Santos ◽  
Giuliana Bueno ◽  
Eder Flores ◽  
Oldair Leite ◽  
Clayton Janoni ◽  
...  
Keyword(s):  
Anodic Stripping Voltammetry ◽  
Extraction Procedure ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Rare Metal ◽  
Western Region ◽  
Natural Occurrence ◽  
Flame Atomic Absorption ◽  
The Western Region ◽  
Environmental Agencies

Thallium (Tl) is a rare metal with toxic effects notably harmful to human health and the environment. In this article, the natural occurrence of Tl was evaluated in a deactivated manganese mine located in the Western region of Bahia, Brazil. The extraction procedure with aqua regia was used to dissolve the soil, sediment, and tailings samples. The Tl content was determined by differential pulse anodic stripping voltammetry (DPASV) and manganese (Mn) and iron (Fe) by flame atomic absorption spectroscopy (FAAS). The Tl levels ranged from 0.64 to 473 mg kg‑1, triggering an alert since most of the samples (soil and sediment) analyzed presented Tl concentrations above 1.0 mg kg-1, recognized as the maximum limit recommended by environmental agencies in North America and Europe.

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