Browsing by Author "Sahoo, P.K"

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Geochemical mapping in stream sediments of the Carajas Mineral Province: Background values for the Itacaiunas River watershed, Brazil
(Elsevier, 2020) Salomao, G.N; Dall'Agnol, R; Sahoo, P.K; Angelica, R.S; de Medeiros, Filho C.A; Ferreira, Junior J.D.S; Sousa da, Silva M; Souza Filho, P.W.M.E; Nascimento, Junior W.D.R; da Costa, M.F; Guilherme, L.R.G; Siqueira, J.O.D.
Multi-elemental analysis of high-density (regional-scale) geochemical surveys is an important strategy for multi-purpose applications, particularly in addressing geochemical background concentrations in different sampling media. This approach was applied to the Itacaiunas River Watershed (IRW), which is situated in the most prominent mining area of Brazil, the Carajas Mineral Province. Microcatchment-based mapping (~50 km2 each) covering the whole extent of IRW was delimited using remote sensing techniques and targeted for sampling. A total of 788 samples, including 27 duplicates, were collected in 2017. The <0.177 mm fraction of all samples was digested by aqua regia and 51 elements were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Geochemical maps for Fe and potentially toxic elements (PTE; As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn) and microcatchment-based distribution maps based on threshold values were constructed for the whole IRW. The stream sediment geochemistry is mainly controlled by the local geologic setting and underlying lithology. Geochemical background (GB) values for 43 elements in stream sediments of the IRW were determined by a variety of methods (Tukey's inner fences -TIF, median +- 2*median absolute deviation - MAD, and percentile-based techniques). The results provided from the different methods show a wide range of values, with the MAD method being considered the most appropriate for deriving GB concentrations. A comparison of reference levels for PTE contemplated in the Brazilian regulation in stream sediments, the threshold concentrations obtained for the IRW area, and different study cases around the world is presented in detail. Our findings provide not only valuable information for selecting potential areas for mineral exploration surveys, but also for evaluating geochemical contaminant effects with time-varying treatments. Studies conducted to determine background values at regional scale are needed for environmental decision making, as well as to attest actions in cases of potential contamination. In the absence of these studies, misleading interpretations of the magnitude of contamination levels in a certain area may cause under- or overestimation of ecological and/or human-health risks of PTE. - 2020 Elsevier Ltd
Multivariate statistics and geochemical approaches for understanding source-sink relationship - a case study from close-basin lakes in Southeast Amazon
(Elsevier, 2020) Moraes, A.M; Sahoo, P.K; Guimar�es, J.T.F; Leite, A.S; Salom�o, G.N; Souza-Filho, P.W.M; J�niora, W.N; Dall'Agnol, R.
Multivariate statistical approaches were applied on geochemical data of lake sediments and the catchment basin materials (Al-enriched crusts and soils) from four upland lakes (namely LB1, LB2, LB3, and LB4) in the Serra da Boca�na, Southeast Amazon, to recognize the geochemical signatures of lake sediments and their link with source rocks. This is also compared with Fe-enriched crusts and soils, which collected from Serra Sul de Caraj�s. The major and trace elements were analyzed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and X-ray Fluorescence (XRF), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), respectively. The data closure effect was reduced by centred log ratio (clr) transformation. The upper continental crust (UCC) normalized patterns show that sediments are mainly enriched with Ti, Fe, P, Se, V and Cr, similar to catchment basin crusts and soils. The distribution of elements varied between lakes, which is mainly influenced by the morphology and lithology of the basin. The chemical index of alternation (CIA) values were very high (>90) for both lake sediments and catchment materials, which indicates intense source area weathering. Index of lateritization (IOL) shows that the catchment crusts are strongly lateralized and it identifies samples between extremely weathered and reworked samples that do not meet the criteria for strict in situ formation. The principal components analysis (PCA) and Spearman correlation matrices based on clr-transformed data revealed four geochemical groups in sediments. The major detritic geochemical association of sediments (Group 1: Al�Ti-Ga-Cr-V-Ti-Nb-Sc, which indicative of mafic/metavolcanic rock; and Group 2: Zr-Hf-HREEs, which refers to the heavy mineral fractions that remain stable during lateritization) had a close relationship with catchment lateritic crust, except a few alterations, which possibly influenced by weathering and transport processes. REE pattern normalized to chondrite and the geochemical ratios show the analogies between the lake sediments and the catchment lateritic crusts. The linear discriminant analysis (LD) and PCA distinguished Al-rich laterites from Fe-rich laterites and indicates that the former (which likely derived from mafic/metavolcanic rocks) is the main source of lake sediments. � 2020 Elsevier Ltd
Quantification of groundwater-agricultural soil quality and associated health risks in the agri-intensive Sutlej River Basin of Punjab, India
(Springer, 2020) Kumar, R; Mittal, S; Peechat, S; Sahoo, P.K; Sahoo, S.K.
The quality of drinking water and agricultural soil significantly affects the health of residents of the area. The quality of groundwater used as drinking and irrigation water along with agricultural soil of an agri-intensive region of the Sutlej River Basin (SRB), Punjab (India), has been investigated in the present paper to further access their impacts on human health. The quality parameters studied are pH, conductivity, cations, anions and trace elements/heavy metals. The spatio-distribution maps of major contaminates have been made. The distribution of major existing groundwater and agricultural soil contaminants has also been illustrated using inverse distance weighting interpolation technique. Further, the Pearson correlation matrix and principal component analysis (PCA) have been applied to explore the correlation and source apportionment analysis for the contaminants. Finally, the health risk assessment study has also been performed. The results showed elevated levels [compared to BIS acceptable limits] of bicarbonate and total hardness in more than 90% groundwater samples, while the concentration of Se and U exceeded in around 25% samples. Spatial distribution maps showed a non-homologous distribution pattern for most of the heavy metals except Zn, indicating their different origins. The significant existence of Se and U in groundwater and low content in soils indicated their geogenic origin. The Gibbs diagram suggested that rock-water interaction is the primary process controlling the chemical evolution of the groundwater in the region. The PCA indicated that Cu, Mn, Pb, NO3? and SO42? in groundwater have an anthropogenic origin, whereas Fe, As and U are mainly of geogenic origin. Significant positive correlations of heavy metals with Fe and Al in soils indicated scavenging of these elements by Fe/Al-oxyhydroxides minerals. Based on SAR, Na%, PI and corrosivity ratio analysis, it can be concluded that groundwater of the region is suitable for irrigation purposes Further, health risk assessment study indicated Cr and As are the possible cancer risk posing elements from both soil and groundwater. Non-carcinogenic risk assessment showed that cumulative exposure (hazard index 1.98) of U (HQ 1.21), NO3? (HQ 0.37) and F? (HQ 0.34) might pose harmful impacts to residents through groundwater ingestion in the long term. Although currently the contaminants in the groundwater, soil system may not pose any human health risks, continuous long-term monitoring is required to keep a check on the changes in their quality with time. 2020, Springer Nature B.V.
Source and background threshold values of potentially toxic elements in soils by multivariate statistics and GIS-based mapping: a high density sampling survey in the Parauapebas basin, Brazilian Amazon
(Springer, 2020) Sahoo, P.K; Dall�Agnol R; Salom�o, G.N; da Silva, Ferreira Junior J; da Silva, M.S; Martins, G.C; e Souza Filho, P.W.M; Powell, M.A; Maurity, C.W; Angelica, R.S; da Costa, M.F; Siqueira, J.O.
A high-density regional-scale soil geochemical survey comprising 727 samples (one sample per each 5 � 5�km grid) was carried out in the Parauapebas sub-basin of the Brazilian Amazonia, under the Itacai�nas Basin Geochemical Mapping and Background Project. Samples were taken from two depths at each site: surface soil, 0�20�cm and deep soil, 30�50�cm. The ground and sieved (< 75��m) fraction was digested using aqua regia and analyzed for 51 elements by inductively coupled plasma mass spectrometry (ICPMS). All data were used here, but the principal focus was on the potential toxic elements (PTEs) and Fe and Mn to evaluate the spatial distribution patterns and to establish their geochemical background concentrations in soils. Geochemical maps as well as principal component analysis (PCA) show that the distribution patterns of the elements are very similar between surface and deep soils. The PCA, applied on clr-transformed data, identified four major associations: Fe�Ti�V�Sc�Cu�Cr�Ni (Gp-1); Zr�Hf�U�Nb�Th�Al�P�Mo�Ga (Gp-2); K�Na�Ca�Mg�Ba�Rb�Sr (Gp-3); and La�Ce�Co�Mn�Y�Zn�Cd (Gp-4). Moreover, the distribution patterns of elements varied significantly among the three major geological domains. The whole data indicate a strong imprint of local geological setting in the geochemical associations and point to a dominant geogenic origin for the analyzed elements. Copper and Fe in Gp-1 were enriched in the Caraj�s basin and are associated with metavolcanic rocks and banded-iron formations, respectively. However, the spatial distribution of Cu is also highly influenced by two hydrothermal mineralized copper belts. Ni�Cr in Gp-1 are highly correlated and spatially associated with mafic and ultramafic units. The Gp-2 is partially composed of high field strength elements (Zr, Hf, Nb, U, Th) that could be linked to occurrences of A-type Neoarchean granites. The Gp-3 elements are mobile elements which are commonly found in feldspars and other rock-forming minerals being liberated by chemical weathering. The background threshold values (BTV) were estimated separately for surface and deep soils using different methods. The �75th percentile�, which commonly used for the estimation of the quality reference values (QRVs) following the Brazilian regulation, gave more restrictive or conservative (low) BTVs, while the �MMAD� was more realistic to define high BTVs that can better represent the so-called mineralized/normal background. Compared with CONAMA Resolution (No. 420/2009), the conservative BTVs of most of the toxic elements were below the prevention limits (PV), except Cu, but when the high BTVs are considered, Cu, Co, Cr and Ni exceeded the PV limits. The degree of contamination (Cdeg), based on the conservative BTVs, indicates low contamination, except in the Caraj�s basin, which shows many anomalies and had high contamination mainly from Cu, Cr and Ni, but this is similar between surface and deep soils indicating that the observed high anomalies are strictly related to geogenic control. This is supported when the Cdeg is calculated using the high BTVs, which indicates low contamination. This suggests that the use of only conservative BTVs for the entire region might overestimate the significance of anthropogenic contamination; thus, we suggest the use of high BTVs for effective assessment of soil contamination in this region. The methodology and results of this study may help developing strategies for geochemical mapping in other Caraj�s soils or in other Amazonian soils with similar characteristics. � 2019, Springer Nature B.V.
Water chemistry and estimation of background levels of elements in surface water bodies from a protected area in the vicinity of Fe deposits, Southeastern Amazon
(Taylor and Francis Inc., 2020) Teixeira, S.S; Dall' Agnol, R; Sahoo, P.K; Salomão, G.N; Guimarães, J.T.F; Costa, M.
This paper aimed to provide the knowledge of water chemistry and quality and background values of the elements in surface waters around the Fe-ore deposits of N3 and N4WSul of Serra dos Carajas, Brazil. Water samples were collected from 17 monitoring points monthly/quarterly between 2013 and 2016 and the elemental analyses were carried out using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The waters are slightly acidic to slightly alkaline in nature and are classified into "good" and "optimum" water quality category. Seasonal variation impacted water quality, with significantly higher content of metals (such as Fed, Fet, and Ald) during the rainy period that is due to more intense surface-runoff and leaching. Comparing with CONAMA 357/05/WHO limits, nonconformities were mainly observed for pH, Fe and Mn, and in some cases for Ald, Znt, Cud, Cdt and Znt, and were significantly higher in the N4WSul area than in the N3. Although, Fe and Mn mostly enter the water bodies from catchment weathering, the poor correlation between Fe and Mn indicated that their source and transport processes are different. In fact, elevated Mnd concentrations associated with low DO content in the dry period are explained by a reductive dissolution of manganese oxides via bacterial decomposition of OM. The background threshold values (BTVs) of elements were estimated by the upper 95% simultaneous limit (USL95; using ProUCL software) and the median ± 2 Median Absolute Deviation (mMAD) method, while the former was considered as the most suitable method for defining BTVs. The BTVs for Al(d), Fe (d), Mn and Zn are mostly exceeding the maximum limits stipulated by the legislation. However, since these areas are located in a protected region, these values are seen as representative of the natural conditions of the study area and reflect geogenic influence. - 2020, - 2020 Informa UK Limited, trading as Taylor & Francis Group.