Environmental and human health risk assessment of potentially toxic elements in rehabilitating iron mine lands in the Brazilian Amazon.

Waste pile substrates from Fe mining may carry potentially toxic elements (PTE). Rehabilitation efforts must maintain soil vegetation cover effectively, avoiding the dispersion of particulate matter and reducing the risk to the environment and human health. Therefore, this study aims to evaluate the pseudo-total and extractable contents, perform chemical fractionation, and assess the bioaccessibility and risk of PTE in waste piles of Fe mining in the Eastern Amazon.

Exploring multi-media geochemical relationships in the southeastern Amazonian basin: A way forward to define source and background levels of potentially toxic elements in lake sediments.

Understanding geochemical source-sink relationships is an important aspect for developing background values of potentially toxic elements (PTEs) in a lake basin. This approach was studied in the Araguaia belt of Amazonia, Brazil. A total of 96 sediments (from 13 sediment core, low-altitude lateritic plateaus; LA2-LA14), 36 surface soils, and 19 catchment crusts/rocks were collected in 2022-2023 and chemical analysis of these samples was performed in the fine fraction (<177 μm) using XRF and ICP-MS.

Optimizing seedling production for the conservation of the threatened Dyckia rariflora (Bromeliaceae).

Objectives: In vitro seed propagation can enhance plant species growth and enable the rapid production of seedlings while preserving genetic variability. This study aimed to develop in vitro seed propagation and acclimatization protocols for Dyckia rariflora to support conservation efforts of this bromeliad endemic to ferruginous campos rupestres. Seed germination and plant growth were tested using MS (Murashige & Skoog) culture medium with varying salt concentrations, sucrose levels, and the presence or absence of polyvinylpyrrolidone (PVP).

The Impact of Rhizospheric and Endophytic Bacteria on the Germination of : A Threatened Rubiaceae of the Amazon Cangas.

(Rubiaceae) is a narrow endemic species from the canga ecosystems of the Carajás National Forest that is facing extinction due to a limited range and habitat disturbance from hydroclimatological changes and mining activities. This study examines the influence of rhizospheric and endophytic bacteria on seed germination to support conservation efforts. Soil samples, both rhizospheric and non-rhizospheric, as well as plant root tissues, were collected.

Green tech soil analysis: a comparison of potentially toxic element contents among urban, agricultural, and gold mining areas in the Eastern Brazilian Amazon.

Artisanal gold mining can lead to soil contamination with potentially toxic elements (PTEs), necessitating soil quality monitoring due to environmental and human health risks. However, determining PTE levels through acid digestion is time-consuming, generates chemical waste, and requires significant resources. As an alternative, portable X-ray fluorescence (pXRF) offers a faster, more cost-effective, and sustainable analysis.

Properties and environmental quality of the overburden and tailings of manganese mining in the Eastern Amazon.

Knowledge about the characteristics of overburden and tailings from manganese (Mn) mining is essential for defining their levels of potentially toxic elements (PTEs) and appropriate environmental management. This study aimed to assess the total and bioavailable contents of PTEs in Mn mining areas in the Eastern Amazon, as well as the associated environmental risks. The samples were collected in areas of overburden and tailings deposition, in addition to forest soils in the Azul mine, Carajás Mineral Province, Brazil.

Immunocytochemical evaluation of aquaporins and cell wall components and their influence on foliar water uptake in Andean Melastomataceae.

Andean ecosystems are characterized by high humidity, mainly from rain and fog events. Because of differences in altitude two Andean ecosystems - sub-Andean forest and Páramo -face different environmental pressures that affect leaf anatomy and cell wall composition and, consequently, species foliar water uptake (FWU) capacity. Here, FWU capacity of eight species in the Melastomataceae was evaluated and found to be related to proportions of cell wall components and aquaporins in the two ecosystems.

Indicators to quantify biodiversity gains for compensation and mineland rehabilitation in the Eastern Amazon.

To connect the protection of natural resources to economic development, environmental rehabilitation is a promising way to repair and compensate for impacts on biodiversity and ecosystem services. Here, we aimed to compare and select potential indicators for the success of different rehabilitating ecosystems to quantify gains in biodiversity and ecosystem services within the Impact Mitigation Hierarchy. We sampled nine environmental variables along rehabilitation chronosequences from rehabilitating (i) iron mining waste piles, (ii) sand quarries, and (iii) compensation areas in the Carajás National Forest.

Enhancing iron biogeochemical cycling for ecosystem restoration: insights from microbial stimuli.

Introduction: The microbial-induced restoration of ferruginous crusts (), which partially cover iron deposits and host unique ecosystems, is a promising alternative for reducing the environmental impacts of the iron mining industry.

Methods: To investigate the potential of microbial action to accelerate the reduction and oxidation of iron in substrates rich in hematite and goethite, four different microbial treatments (water only as a control - W; culture medium only - MO; medium + microbial consortium - MI; medium + microbial consortium + soluble iron - MIC) were periodically applied to induce iron dissolution and subsequent precipitation. Except for W, all the treatments resulted in the formation of biocemented blocks.

Clean and accurate soil quality monitoring in mining areas under environmental rehabilitation in the Eastern Brazilian Amazon.

Soil quality monitoring in mining rehabilitation areas is a crucial step to validate the effectiveness of the adopted recovery strategy, especially in critical areas for environmental conservation, such as the Brazilian Amazon. The use of portable X-ray fluorescence (pXRF) spectrometry allows a rapid quantification of several soil chemical elements, with low cost and without residue generation, being an alternative for clean and accurate environmental monitoring. Thus, this work aimed to assess soil quality in mining areas with different stages of environmental rehabilitation based on predictions of soil fertility properties through pXRF along with four machine learning algorithms (projection pursuit regression, PPR; support vector machine, SVM; cubist regression, CR; and random forest, RF) in the Eastern Brazilian Amazon.

Assessment of the reproduction of six collembolan species in tropical soils naturally rich in potentially toxic elements.

Laboratory ecotoxicological tests are important tools for the management of environmental changes derived from anthropogenic activities. Folsomia candida is usually the model species used in some procedures. However, this species may not be sufficiently representative of the sensitivity of the other collembolan species.

Exogenous Nitric Oxide Alleviates Water Deficit and Increases the Seed Production of an Endemic Amazonian Canga Grass.

Open pit mining can cause loss in different ecosystems, including damage to habitats of rare and endemic species. Understanding the biology of these species is fundamental for their conservation, and to assist in decision-making. is an annual grass endemic to the Amazon canga ecosystems, which comprise rocky outcrop vegetation covering one of the world's largest iron ore reserves.

Acquiring Iron-Reducing Enrichment Cultures: Environments, Methods and Quality Assessments.

Lateritic duricrusts cover iron ore deposits and form spatially restricted, unique ecosystems endangered by mining. Iron cycling, i.e.

Molecular Mechanisms Underlying Success in Amazonian Rehabilitating Minelands.

is endemic to Brazil and grows in ferruginous outcrops () in Serra dos Carajás, eastern Amazon, where one of the largest iron ore deposits in the world is located. Plants that develop in these ecosystems are subject to severe environmental conditions and must have adaptive mechanisms to grow and thrive in . is a native species used to restore biodiversity in post-mining areas in .

Evolutionary history of marginal habitats regulates the diversity of tree communities in the Atlantic Forest.

Background And Aims: The Atlantic Forest biodiversity hotspot is a complex mosaic of habitat types. However, the diversity of the rain forest at the core of this complex has received far more attention than that of its marginal habitats, such as cloud forest, semi-deciduous forest or restinga. Here, we investigate broad-scale angiosperm tree diversity patterns along elevation gradients in the south-east Atlantic Forest and test if the diversity of marginal habitats is shaped from the neighbouring rain forest, as commonly thought.

Cross-species transcriptomes reveal species-specific and shared molecular adaptations for plants development on iron-rich rocky outcrops soils.

Background: Canga is the Brazilian term for the savanna-like vegetation harboring several endemic species on iron-rich rocky outcrops, usually considered for mining activities. Parkia platycephala Benth. and Stryphnodendron pulcherrimum (Willd.

Proteomic Profiling and Rhizosphere-Associated Microbial Communities Reveal Adaptive Mechanisms of Kunth in Eastern Amazon's Rehabilitating Minelands.

Kunth is native to ferruginous rocky outcrops (known as ) in the eastern Amazon. Native are considered hotspots of biological diversity and have one of the largest iron ore deposits in the world. There, can grow in post-mining areas where molecular mechanisms and rhizospheric interactions with soil microorganisms are expected to contribute to their establishment in rehabilitating minelands (RM).

Changes in soil properties during iron mining and in rehabilitating minelands in the Eastern Amazon.

Open-cast iron mining causes drastic disturbances in soil properties. Recovery of soil chemical and physical properties is essential for successful revegetation and landscape rehabilitation. To identify changes in soil properties during the mining and revegetation process, soil samples were collected from undisturbed sites represented by forest and ferriferous savannas stocking above iron outcrops, called "cangas," in open-pit benches, and in rehabilitation chronosequences of iron waste piles in the Carajás Mineral Province (CMP), Eastern Amazon, Brazil.

Copper mining in the eastern Amazon: an environmental perspective on potentially toxic elements.

Mining activity is of great economic and social importance; however, volumes of metallic ore tailings rich in potentially toxic elements (PTEs) may be produced. In this context, managing this environmental liability and assessing soil quality in areas close to mining activities are fundamental. This study aimed to compare the concentrations of PTEs-arsenic (As), barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), molybdenum (Mo), nickel (Ni), lead (Pb) and zinc (Zn)-as well as the fertility and texture of Cu tailings and soils of native, urban and pasture areas surrounding a Cu mining complex in the eastern Amazon.

Native Amazonian Grasses Show Distinct Nitrogen Growth Responses in Iron Mining Substrates.

Native species may have adaptive traits that are advantageous for overcoming the adverse environmental conditions faced during the early stages of mine land rehabilitation. Here, we examined the nitrogen (N) growth responses of two native perennial grasses ( and ) from in nutrient-poor iron mining substrates. We carried out vegetative propagation and recovered substantial healthy tillers from field-collected tussocks of both species.

Natural regeneration triggers compositional and functional shifts in soil seed banks.

Secondary forests emerging during traditional shifting cultivation practices are increasingly recognized for their fulfillment of ecosystem services and mitigation potential of climate change and biodiversity losses. The soil seed bank as a recruit reservoir is a limiting factor for natural forest regeneration of such secondary forests and is decisive for the formation and restitution of the post-disturbance community. The aim of this study was to compare the composition of the soil seed bank along a natural regeneration chronosequence from the Caxiuanã National Forest, eastern Amazon, including old-growth reference sites.

Accelerating microbial iron cycling promotes re-cementation of surface crusts in iron ore regions.

Accelerating microbial iron cycling is an innovative environmentally responsible strategy for mine remediation. In the present study, we extend the application of microbial iron cycling in environmental remediation, to include biocementation for the aggregation and stabilization of mine wastes. Microbial iron reduction was promoted monthly for 10 months in crushed canga (a by-product from iron ore mining, dominated by crystalline iron oxides) in 1 m containers.

Phosphorus lability increases with the rehabilitation advance of iron mine land in the eastern Amazon.

Impacted areas by iron mining may face challenges in the management of phosphate fertilization and reduced efficiency of rehabilitation practices, thus extending the time required for the rehabilitation of these areas. The objective of this study was to evaluate phosphorus (P) lability in soils of native forest and ferriferous canga areas (savanna vegetation above ironstone outcrops covering iron ore deposits) and in iron mine waste piles undergoing rehabilitation. Benches of the analysed waste pile differ in age of rehabilitation: as the initial rehabilitation stage (INI), we consider benches with fewer than 3 years of rehabilitation; the intermediate stage (INT) were benches with up to 5 years of rehabilitation; and the advanced rehabilitation stage (ADV) corresponds to benches with more than 8 years of rehabilitation activities.

Combining genotype, phenotype, and environmental data to delineate site-adjusted provenance strategies for ecological restoration.

Despite the importance of climate-adjusted provenancing to mitigate the effects of environmental change, climatic considerations alone are insufficient when restoring highly degraded sites. Here we propose a comprehensive landscape genomic approach to assist the restoration of moderately disturbed and highly degraded sites. To illustrate it we employ genomic data sets comprising thousands of single nucleotide polymorphisms from two plant species suitable for the restoration of iron-rich Amazonian Savannas.

Integrating environmental variables by multivariate ordination enables the reliable estimation of mineland rehabilitation status.

Despite the wide variety of variables commonly employed to measure the success of rehabilitation, the assessment and subsequent definition of indicators of environmental rehabilitation status are not simple tasks. The main challenges are comparing rehabilitated sites with target ecosystems as well as integrating individual environmental and eventually collinear variables into a single tractable measure for the state of a system before effective indicators that track rehabilitation may be modeled. Furthermore, a consensus is lacking regarding which and how many variables need to be surveyed for a reliable estimation of rehabilitation status.