Browsing by Author "Dall'Agnol, Roberto"

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Changes in the surface water quality of a tropical watershed in the southeastern amazon due to the environmental impacts of artisanal mining
(Elsevier Ltd, 2023-04-12T00:00:00) Salom�o, Gabriel Negreiros; Dall'Agnol, Roberto; Sahoo, Prafulla Kumar; Almeida, Gabriel Soares de; Amarante, Rafael Tarantino; Zeferino, Leiliane Bozzi; Lopes, Jo�o Paulo Nobre; Souza Filho, Pedro Walfir Martins e; Costa, Normara Yane Mar da; Guimar�es, Jos� Tasso Felix; Silva, Marcio Sousa da; Martins, Gabriel Caixeta; Teixeira, Mayara Fraeda Barbosa; Marques, Eduardo Duarte; Ang�lica, R�mulo Sim�es; Ara�jo, Wilker Emmanoel Oliveira
The expansion of areas of human occupation and the increase in economic activity and deforestation are negatively impacting the Amazon ecosystem. Situated in the Caraj�s Mineral Province in the southeastern Amazon, the Itacai�nas River Watershed (IRW) encompasses several active mines and has a historical record of intense deforestation primarily linked with the expansion of pasturelands, but also of urban areas, and mining activities. Industrial mining projects are subjected to strict environmental control, but artisanal mining (ASM; �garimpos�) sites have not been controlled, despite their known environmental impacts. In recent years, the opening and expansion of ASM in the IRW for the exploitation of mineral resources (Au, Mn, and Cu) have been remarkable. This study presents evidence of anthropogenic impacts, mainly caused by ASM, on the quality and hydrogeochemical characteristics of the IRW surface water. The hydrogeochemical data sets of two projects carried out in the IRW, during 2017 and from 2020 until present, were used to evaluate these impacts within the region. Water quality indices were calculated for the surface water samples. For the whole IRW, water collected during the dry season tended to yield better quality indicators in comparison to those collected during the rainy season. Two sampling sites at Sereno Creek showed very poor water quality and extremely high concentrations of Fe, Al, and potentially toxic elements over time. From 2016 to 2022, ASM sites increased markedly. Moreover, there are indications that Mn exploitation via ASM in Sereno hill is the main source of contamination in the area. New trends of ASM expansion were observed along the main watercourses, related to the exploitation of Au from alluvial deposits. Similar anthropogenic impacts are registered in other regions of the Amazon and environmental monitoring should be encouraged to assess the chemical safety of strategic areas. � 2023 Elsevier Ltd
Geochemical mapping in stream sediments of the Caraj�s Mineral Province, part 2: Multi-element geochemical signatures using Compositional Data Analysis (CoDA)
(Elsevier Ltd, 2021-04-30T00:00:00) Salom�o, Gabriel Negreiros; Dall'Agnol, Roberto; Ang�lica, R�mulo Sim�es; Sahoo, Prafulla K.; Wang, Xueqiu
The geological imprint on the geochemical background in stream sediment of the Itacai�nas River Watershed (IRW), located in the most prominent mining area of Brazil, the Caraj�s Mineral Province, was evaluated. The stream sediment dataset from the Itacai�nas Geochemical Mapping and Background Project of the Instituto Tecnol�gico Vale was used to address multi-element associations and for the definition of surface geochemical compartments by applying a series of multivariate geostatistics tools and geoprocessing techniques, through the Compositional Data Analysis (CoDA) perspective. In this study, the geochemical dataset was processed for centered log-ratio (clr) transformation prior to the Principal Factor Analysis (PFA). The spatial distribution of factor scores derived from PFA indicates a pronounced control on stream sediment geochemistry by the underlying geological setting and lithology. Relevant hidden correlations were observed among the nine extracted factors. An unsupervised classification based on k-means clustering algorithm was performed for the factor scores of 761 stream sediment samples. A multiproxy approach that combines the cluster classification and geoprocessing tools revealed a strong similarity in the spatial distribution of different geochemical compartments and geological domains of the IRW. Threshold values of 51 elements were calculated by a variety of statistical methods for references to the main four geological domains of the IRW defined using the geological framework and the geochemical compartments. These values were then compared to the background concentrations of the entire study area and to the investigation levels proposed by the Brazilian environmental agencies for potentially toxic elements. The new threshold values for the geochemical compartments of the IRW can be used for improving the assessment of environmental impact by anthropic activities, and to establish more realistic threshold values for different chemical elements in stream sediments. This study provides useful information for new mineral development projects and ore prospects, with potential benefit to the mineral sector and industry. � 2021
Mercury in multimedia system of Itacai�nas Basin, Brazilian Amazon: An integrated approach to understand its distribution, origin, and ecological risk
(Academic Press Inc., 2023-01-23T00:00:00) Sahoo, Prafulla Kumar; Dall'Agnol, Roberto; Sim�es Rolo de Deus, Simonny do C.; Salom�o, Gabriel Negreiros; Felix Guimar�es, Jos� Tasso; Angelica, R�mulo Sim�es; Ramos, Silvio Junio; Furtado da Costa, Marlene; Oswaldo de Siqueira, Jose
This study presents the first integrated study on total Hg (THg) level in surface soil (SS), bottom soil (BS), stream sediments (SD), lake sediments (LS), stream water (SW), and lake water (LW) of Itacai�nas River Watershed (IRW), Brazil to investigate the source and distribution of Hg in different environmental media considering contrasts of geological domains and sub-basins and its potential ecological and human risk. Hg content in most of the soils and sediments were above the upper crustal average values (56 ?g/kg), however, when compared to the legal limits set by the Resolution CONAMA (Conselho Nacional de Meio Ambiente: soil 500 ?g/kg; sediment 486 ?g/kg), only 1 soil sample from Parauapebas sub-basin and 4 sediment samples from Viol�o Lake exceeded the limit. None of the SW and LW samples (<0.2 ?g/L; CONAMA limit for Class II freshwater) are markedly contaminated by Hg. The SS and BS show similar contents and spatial distribution of Hg with higher contents being registered mostly in the Itacai�nas and Parauapebas sub-basins, which are closely correlated with SD. This suggests that Hg levels are largely of geogenic origin and anthropogenic effect is highly limited. Principal Component Analysis (PCA) results show that Hg is strongly associated with total organic carbon (TOC), loss on ignition (LOI), and SO3, indicating organic matter as the main factor controlling the distribution of Hg and this is the major cause of accentuated Hg enrichment in lake sediments. The ecological risk index revealed a low pollution risk for most of the solid samples, except 11% LS and <1.5% SS and SD samples, which registered moderate risk. Health risk assessment indicated no adverse non-carcinogenic health effect on either adults and children in terms of Hg contamination. This information will be useful for Hg risk assessment in the Caraj�s region and future environmental research in this direction in the Amazonia. � 2023 Elsevier Inc.
Occurrence, distribution, and environmental risk assessment of heavy metals in the vicinity of Fe-ore mines: a global overview
(Taylor and Francis Ltd., 2021-06-08T00:00:00) Sahoo, Prafulla Kumar; Powell, Mike A.; Martins, Gabriel Caixeta; Dall'Agnol, Roberto; Salom�o, Gabriel Negreiros; Mittal, Sunil; Pontes, Paulo R�genes Monteiro; Guimar�es, Jos� Tasso Felix; de Siqueira, Jose Oswaldo
Several studies have investigated the consequences of heavy metal contamination in the vicinity of individual Fe ore mines, however, at present there are no systematic studies that consider the global scenario; this work strives to begin filling that gap. This review includes data reported for metals and pH in soil, overburden, sediment, tailings, and water in the vicinity of Fe mines at sites in 19 countries over the past 15 years. Elements of concern include As, Fe, Mn, Cd, Cu, Cd, Co, Pb, Ni and Zn. Various pollution and ecological risk indices were applied to evaluate environment risks by heavy metals. � 2021 Informa UK Limited, trading as Taylor & Francis Group.
Soil-sediment linkage and trace element contamination in forested/deforested areas of the Itacai�nas River Watershed, Brazil: To what extent land-use change plays a role?
(Elsevier B.V., 2022-03-08T00:00:00) Dall'Agnol, Roberto; Sahoo, Prafulla Kumar; Salom�o, Gabriel Negreiros; de Ara�jo, Alessandra Danieli Miranda; da Silva, Marcio Sousa; Powell, Mike A.; Junior, Jair Ferreira; Ramos, Silvio Junio; Martins, Gabriel Caixeta; da Costa, Marlene Furtado; Guilherme, Luiz Roberto Guimar�es
Trace elements (TE) contamination in forested areas of the Itacai�nas River Watershed (IRW), Brazilian Amazon, arouses growing interest owing to the rapid deforestation and mining activities. In this study, soils (surface, SS; bottom, BS) and stream sediments (SD) from forested/deforested areas of IRW were analyzed with the aim of (1) evaluating the major sources of TE (mainly As, Ba, Cd, Cu, Co, Cr, Hg, Mo, Mn, Ni, Pb, V, and Zn), and (2) examining the soil-sediment TE link related to land-use change and/or geologic factors. Compositional data analysis (CoDA) was used to eliminate data closure issues and the centred log-ratio (clr) transformation yielded better results in Principal Component Analysis (PCA). The TE distribution pattern was significantly different (p < 0.05) between forested and deforested areas, but in both areas the TE distribution pattern is significantly correlated between SS, BS, and SD, indicating a strong lithogenic control. PCA (clr-transformed) identified the major geochemical bedrock signature as Fe-Ti-V-Cu-Cr-Ni, which is nearly similar in soil and sediments. The more accentuated enrichment and the maximum number of anomalies of these elements were found in the Caraj�s Basin and are highly coincident with mineral deposits/local lithologies without clear indication of anthropogenic contamination from point sources. Besides geogenic factors, deforestation is also affecting TE distribution in the basin. In deforested areas, Mn was significantly enriched in the surface horizon. Furthermore, linear regression analysis shows stronger TE relationships between soils and sediments in deforested areas than in forested ones, reflecting higher erosion in the former. This could be the reason for the relatively higher enrichment of TE (e.g., Fe, Mn, Cu, Cr, Ni) in deforested sediments. The TE contamination using regional background values provides more accurate results than worldwide reference values. Thus, the former should be considered for a more realistic environmental risk assessment in IRW and other forest ecosystems in the Brazilian Amazon. � 2022 Elsevier B.V.