Contamination by lead in sediments at Toledo River, hydrographic basin of PARANÁ III

Abstract

Due to intense agricultural and industrial activities, the environment has been affected by increasing amounts of pollutants, such as lead, a toxic heavy metal. When introduced to the environment, toxic metals are distributed and incorporated into the liquid medium, sediments, and aquatic biota; bioaccumulating. This research aimed to identify and quantify the levels of toxic metals present in the waters and sediments of Toledo River, compare the obtained results with legislation and other studies, as well as to evaluate the possible pollutant sources of the water body. Six water and sediment samples were taken at seven strategic sites. The concentrations of Cu, Zn, Fe, Mn, Cd, Pb, and Cr in water were compared to the maximum limits established by Brazilian legislation IN CONAMA No. 357/05, for class II fresh waters. The sediment samples were submitted to nitroperchloric digestion, and then the total concentrations of the metals were determined by flame atomic absorption spectrometry (FAAS). The toxicological quality of the Toledo River has been considerably affected by the activities carried out in its surroundings, such as extensive areas of agriculture, pig farming and industrial areas, causing concentrations of Cd, Fe, and mainly Pb, which is observed at concentrations higher than value allowed by the legislation.

Effective Cd2+ removal from water using novel micro-mesoporous activated carbons obtained from tobacco: CCD approach, optimization, kinetic, and isotherm studies

“…For this, a reactor (Erlenmeyer) was considered for each AC (CT in natura + CO 2 and CT NaOH + CO 2 ). Then, the reactors were stirred in time intervals of 10,20,30,40,50,60,80,100,120,140,160, and 180 min. At each point, 15 mL aliquots were taken, filtered (on qualitative filter paper), and the residual Cd concentration was determined by FAAS [41].…”

“…This last statement has especial importance regarding water treatment technologies. In the last decades, industrialization, agriculture, and expanding urbanization have increased the pressure on fresh water bodies, causing high levels of pollutants, in many cases of contamination with metals [3,4], pesticides [5][6][7], organic matter [8,9], and their environmental impacts on sediments, benthic organisms, humans, i.e., the trophic chain as a whole [7,[10][11][12][13].…”

Determinação voltamétrica de bismuto em sistema aquoso bifásico e elaboração de um eletrodo de filme de bismuto a partir de fonte secundária : uma proposta de sustentabilidade

“…Na legislação, são definidos limites máximos permitidos em água de acordo com seu enquadramento. Para o enquadramento classe 1águas doces: 0,001 mg/L para Cd 2+ e 0,01 mg/L para Pb 2+ [108].…”