Heavy metal distribution in recent sediments along the Tiet^|^ecirc; River basin (S^|^atilde;o Pauro, Brazil)

Abstract

Variations in the aquatic environmental conditions can produce a release of heavy metals from the sediment to the water resulting in an increase of their bioavailability and consequent toxicity (Young et al., 1987;Wen and Allen, 1999). This aspect can be further investigated when the samples are analyzed in recent sediments, allowing a detailed study of heavy metals in association with the bioavailable and residual fractions, involving materials of different origins. The distribution and quantification of heavy metals in river sediments are usually based on concentrations obtained from extraction procedures and compared with the natural background levels (Salomons and Förstner, 1984).The Tietê River, with 900 km of extension, is the longest river of the southeast part of Brazil. Its drainage basin, with a population of nearly 25 million people, is important for food and energy production, with more than ten hydroelectric power plants along the main channel of the river and tributaries. Over the years, with the increased population and consequent development of industry and agriculture, the river water and sediment quality deteriorated. In recent years, attention has been focused to the problem of river pollution related to the presence of heavy metals in dissolved and particulate loads (Mortatti and Probst, 2010).This paper aims to characterize the heavy metal distribution in the recent sediments along the Tietê River (from headwater to the mouth) and evaluate the degree of pollution in the river basin, considering a regional background level. (Received March 31, 2011; Accepted September 22, 2011) The distribution of heavy metals in recent sediments deposited along the Tietê River, a highly polluted river in southeast region of Brazil was studied. Around the metropolitan area of São Paulo city (25 million people), the pollution is related to municipal wastes and industrial effluents with reinforced downstream by agricultural activities. The observed increase of heavy metal concentrations is particularly important for Zn in the upper basin and Cu, Co and Cr at mouth. Geo-accumulation index calculation, related to the regional background, showed that the sediments along the basin are seriously polluted by heavy metals of anthropogenic origin, mainly Cu, Co, Cr and Zn. Calculated index suggests medium to very strongly pollution. Heavy metal distribution in recent sedimentsKeywords: heavy metals, Tietê River, sediments, geo-accumulation index, pollution INTRODUCTIONHeavy metals are considered one of the greatest threats to the human health, due to their toxic effects on the environment. They are present in various compartments (atmosphere, water, soil, sediments and living organisms) and their forms are controlled by physical and chemical conditions as well as by biological processes. Natural occurrence of heavy metals is related to distribution of clastic mineral detritus from soil, rock and volcanic eruptions (Sanei et al., 2001;Mortatti and Probst, 2010), and from anthropogenic activities related to agricultu...

Distribution of heavy metals in the geochemical phases of sediments from the Tietê River, Brazil

“…The average concentrations of total heavy metals determined in the Tietê riverbed sediments were much higher than the regional background levels observed by Mortatti et al (2012) at the upper, middle and lower parts of the Tietê River basin. This demonstrates that the Tietê riverbed sediments have been polluted by heavy metals originated by anthropogenic activities along the drainage basin.…”

Evaluation of heavy metal content in Qaroun Lake, El-Fayoum, Egypt. Part I: Bottom sediments

“…However, this trend is not proved for all elements, which means that the grain size is not the only factor affecting the metal concentrations. Drains effluents, Organic matter content, lithogenic sources and mineralogical composition of sediments as well as the physical, chemical and biological processes are others factors share in controlling the sediment-heavy metal content (Hang et al, 2009;Mortatti, Meneghelg, & Probst, 2011;Presley, Trefry, & Shokes, 1980).…”

Combined analysis of trace elements and isotopic composition of particulate organic matter in suspended sediment to assess their origin and flux in a tropical disturbed watershed

“…Since the study of Martin and Meybeck (1979), which showed that the composition of suspended matter transported by the world's largest rivers, there has been a growing interest to estimate suspended sediment transport in rivers and the elements/chemical compounds associated with them (Horowitz, 2008;Walling, 2013). Some studies stand out for using the comparison of a reference geochemical background, through the calculation of enrichment factors (EF) in bottom sediments (Alves et al, 2010;Amorim et al, 2009;Cotta et al, 2006;Gaillardet et al, 2003;Harikumar and Jisha, 2010;Probst, 2006a, 2006b;Kendall and Doctor, 2003;Kersten and Forstner, 1995;Meybeck et al, 2007;Miller et al, 2007;Mortatti et al, 2012;Mozeto et al, 2003;Nasrabadi et al, 2010;Salomons and Forstner, 1984;Shotyk et al, 2000) as well as in suspended sediments Probst, 2006a, 2006b;Kucuksezgin et al, 2008;Mortatti and Probst, 2010;Ollivier et al, 2011;Radakovich et al, 2008;Viers et al, 2009;Woitke et al, 2003).…”

“…For the anthropogenic contribution related to domestic sewage the d 13 C, d 15 N and C:N ratios range from À26 to À22 / oo , from þ7 to þ22 / oo and from 7 to 11, respectively (Barros et al, 2010;Gao et al, 2012;Mayer et al, 2002). In Brazil, the few studies that have evaluated the origin and fluvial fluxes of suspended sediment were conducted in the São Paulo State (Alves et al, 2010;Cotta et al, 2006;Fernandes et al, 2012;Mortatti and Probst, 2010;Mortatti et al, 2012). However, none of these studies have associated suspended sediments to particulate organic matter, with POM was only studied in the Piracicaba River basin, also located in the São Paulo State (Krusche et al, 2002), and in the Guanabara Bay, in Rio de Janeiro State (Carreira et al, 2002) and Babitonga Bay, in Santa Catarina State (Barros et al, 2010).…”