Heavy metal status of sediment in river Cauvery, Karnataka

Abstract

The purpose of this research work was to appraise extent of heavy metals in sediment and the degree to which its quality tainted seasonally and spatially in river Cauvery. In this study, heavy metals such as Fe, Zn, Ni, Mn, Pb, Cu, Co, Cd and Cr were analysed in sediments. Results were compared with sediment quality guidelines from various derived criteria. Twenty-five sampling points were selected based on geographical proximity of agricultural fields and industrial discharges; river-tributary confluence points; settlements located along the river bank; ritual and recreational activities. Sampling was done for the period of 3 years (2007 to 2009). Digestion of the samples was done by microwave-assisted digestion technique. Analysis was carried out using flame furnace atomic absorption spectrophotometer, and results are expressed in micrograms per gram. The mean concentration of Fe (11144 μg/g) followed by Mn (1763.3 μg/g), Zn (93.1 μg/g), Cr (389 μg/g), Ni (27.7 μg/g), Cu (11.2 μg/g), Pb (4.3 μg/g), Co (1.9 μg/g) and Cd (1.3 μg/g) remained within the levels of sediment quality guidelines. Multivariate statistical techniques such as principal component analysis and cluster analysis (CA) were employed to better comprehend the controlling factors of sediment quality and spatial homogeneity among the stations. The sediment geo-accumulation index (I(geo)) showed maximum value of Cd (2.69) and least value of Mn (-1.44). The geo-accumulation class (I(geo) class) was in the sequence as follows: Cd>Zn>Pb>Cr>Cu>Co>Ni>Fe>Mn. Negative total geo-accumulation indices (I(tot)) revealed that mean concentration of heavy metals in the river bed sediment are lower than their respective shale values. The statistical analysis of inter-metallic relationship revealed the high degree of correlation among the metals indicated their identical behaviour during transport. This study concludes that insignificant geo-accumulation with metals except Cd (moderate contamination), Pb and Zn (slight contamination) principally in downstream stretch may perhaps deteriorate the sediment quality due to intensification anthropogenic influences. It also proves that extent of existing metal concentrations in sediments of river Cauvery in Karnataka not exceeded the toxic limit, and there is no peril to the aquatic life.

Assessment of heavy metal contamination in the sediment of the River Ghaghara, a major tributary of the River Ganga in Northern India

“…Ni concentration in sediments of the river Ghaghara is compared with other rivers of the World and is presented in Table 5. Ni concentration was 27.7 mg/kg for the river Cauvery (Raju et al 2012), 67.1 mg/kg for the river Euphrates (Salah et al 2012), 41.9 mg/kg for the river Yangtze (Wang et al 2011), and 68 mg/kg was the World average (Turekian and Wedepohl 1961). Nickel can be accumulated in aquatic biota, but its magnification in the food chain is not confirmed.…”

Calidad De Sedimentos Asociada a Actividades Antrópicas en Lagunas Costeras Semiáridas Subtropicales De La Costa Central Este Del Golfo De California

“…La alta correlación entre Fe y Zn (r = 0.533), Fe y Cu (r = 0.747), Fe y Mn (r = 0.649) puede significar que estos metales tengan fuentes comunes o un comportamiento semejante durante su transporte (Raju et al 2012). Arunachalam et al (2014), reportan una correlación de Pearson negativa para los pares de Cd vs. Cu, Cr, Pb, Ni, Zn, Mn y Fe pero no explican a qué puede estar realcionada.…”

Principal Component Analysis of Integrated Metal Concentrations of Bogacayi Riverbank Sediments in Turkey

“…"Heavy metals" refers to metallic elements with similar chemical properties that are toxic, persistent, non-biodegradable, and poisonous -even at lower concentrations [3][4][5]. They can either be introduced into the environment naturally (by chemical leaching of bedrocks, water drainage basins, and runoff from banks) and/or from anthropogenic sources (mining operations, disposal of industrial wastes, applications of biocides for pests, automobile exhausts, and combustion by-production from coal-burning power plants [6][7][8][9][10]. Most heavy metals introduced in the environment are usually known to be trapped in sediments by forming stable complexes with sediment organic matter, carbonates, and iron (Fe) -manganese (Mn) oxides [11,12].…”