Copper(II) and Nickel (II) Complexation Capacity of Dissolved Organic Matter from Rivers of Agricultural and Urban Areas in the State of São Paulo

Amanda M Tadini,Mariele B Campanha,Altair B Moreira,Márcia C Bisinoti

doi:10.5935/0103-5053.20130224

Abstract

This study had as main objective to determine the complexing ability of the Organic Matter (OM) from typical agricultural areas and from urban areas with copper and nickel ions. The samples were collected during the dry and rainy seasons and were subjected to study the complexing capacity and OM conditional stability constant with Cu(II) and Ni(II) ions using a luminescence spectrofluorometer and tangential flow ultrafiltration system. The conditional stability constant values (log Kc) of OM with the copper ion varied from 0.04 to 1.35 with the highest value obtained for the place with the largest dissolved organic carbon (DOC 2.73-2.43 mg L-1) and the lowest for the smallest site DOC, corroborating the degree of aromaticity. We can conclude that the Dissolved Organic Matter (DOM) of the bodies of water in agricultural and urban areas contained a lower number of binding sites when compared with other locations.

Highlights

The natural organic matter (NOM) present in environmental areas is the result of several stages of chemical and microbiological degradation involving plant and animal residues and can vary from one body of water to another, depending on the type of use and the occupation of the land.[1,2,3,4,5,6,7] The NOM participates in many chemical and biological processes in natural waters, playing an important role in the speciation of metals, having a greater affinity for divalent cations, such as copper and nickel, in aquatic environments.[8,9] Changes in the soil composition and water cycle caused by anthropicAnother property of NOM is its ability to complex pollutants, especially metals, which may result in complexation and/or reduction reactions, absorption and desorption and other one whose are known to affect the availability of metals for the biota, may affect the transport, accumulation and concentration of these metal species in the planktonic food chain through changes in turbidity and interaction with nutrients, altering the photic zone.[3,4] This process can influence the toxicity of the metal in the environment, once the form of the complex, the metal, is generally less available to interact with the biota.[13,15] In the characterization of the formation of the NOM-metal complex, it is important to consider factors such as the Copper(II) and Nickel (II) Complexation Capacity of Dissolved Organic MatterJ
We observe peaks near 405 nm, which can be associated with aromatic groups containing five and seven rings; these peaks are more intense for the regions of study with agriculture influence such as points 3 and 4.13,37,49,50 Peravouri and co-authors,[49] conducted tests on samples of surface water from lakes in Southern Finland in synchronized mode, and the results showed peaks lex/lem to 400/418 nm can be attributed to polycyclic aromatic compounds with five rings fused benzene
The Dissolved Organic Matter (DOM) for rivers sampled ranged according to the season, with higher values obtained for the dry period, suggesting that the burning of sugarcane may be one of the factors responsible for the increase of organic matter during the harvest period

Summary

Introduction

The natural organic matter (NOM) present in environmental areas is the result of several stages of chemical and microbiological degradation involving plant and animal residues and can vary from one body of water to another, depending on the type of use and the occupation of the land.[1,2,3,4,5,6,7] The NOM participates in many chemical and biological processes in natural waters, playing an important role in the speciation of metals, having a greater affinity for divalent cations, such as copper and nickel, in aquatic environments.[8,9] Changes in the soil composition and water cycle caused by anthropicAnother property of NOM is its ability to complex pollutants, especially metals, which may result in complexation and/or reduction reactions, absorption and desorption and other one whose are known to affect the availability of metals for the biota, may affect the transport, accumulation and concentration of these metal species in the planktonic food chain through changes in turbidity and interaction with nutrients, altering the photic zone.[3,4] This process can influence the toxicity of the metal in the environment, once the form of the complex, the metal, is generally less available to interact with the biota.[13,15] In the characterization of the formation of the NOM-metal complex, it is important to consider factors such as the Copper(II) and Nickel (II) Complexation Capacity of Dissolved Organic MatterJ.

Results

Conclusion