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In this study, four systems (S1, S2, S3, and S4) were evaluated to determine whether basic oxygen furnace sludge (BOFS), mainly composed of Fe (84%, mostly as elemental Fe and FeO), Ca (3%, as CaCO3), and Si (1%), is capable of removing As-spiked, Mn, Mg, and sulfate from an industrial acid mine drainage (AMDi) collected in a gold mine in Minas Gerais, Brazil. In the S1 system (BOFS/deionized water pH 2.5), the stability of the residue was evaluated for 408 h under agitation. The results showed that only Ca and Mg were solubilized, and the pH increased from 2.5 up to 11.4 within the initial 24 h and kept still until the end of the experiment (408 h). The S2 system (BOFS/AMDi) achieved 100% removal of As and Mn, and 70% removal of sulfate after 648 h. In the first 30 min, the pH increased from 2.5 to 10, which was maintained until the end of the experiment. The removal of As, Mn, and sulfate in the presence of hydrogen peroxide (S3 and S4 systems - BOFS/AMDi/H2O2) was similar to that in the S2 system, which contained only BOFS. The formation of iron oxides was not accelerated by H2O2. As regards the removal of arsenic and sulfate species, the formation of incipient calcium arsenate and calcium sulfate dehydrated was indicated by X-ray diffraction analysis and PHREEQC modeling. Dissolved manganese and magnesium precipitated as oxides, according to the geochemical modeling. After contact with AMDi, the raw BOFS, initially classified as hazardous waste, became a non-inert waste, which implies simplified, less costly disposal. Except for sulfate, the concentrations of all the other elements were below the maximum permitted levels.

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A comprehensive characterization was performed to investigate the composition and mineralogy of soils from a gold mining region and their correlation with arsenic (As) total concentration and its bioaccessible fraction. The arsenic bioaccessible (BAC) fraction was determined through in vitro test and calculated as the ratio between the amounts of As released and the total As concentration in the soil sample. Among the minor constituents of environmental concern, only arsenic is significantly higher (median of 748.0 mg kg-1) than the national guidelines (agricultural, 35 mg kg-1 and residential, 55 mg kg-1). All the other trace elements showed concentrations below the investigation values established for residential areas. The mean bioaccessible As was 7.0 mg kg-1, with a median value of 4.4 mg kg-1, and a median As BAC percentage of 0.7%. The Brunauer-Emmett-Teller (BET) surface area showed a consistent increase with the increase of the acid-soluble Al content in the soil samples. The distribution of As in the soil samples is not correlated with the abundance of As-minerals and the fraction of adsorbed As. Arsenic was shown to be trapped in oriented aggregates of crystalline (Al-)Fe-(hydr)oxides nanoparticles (the main metalloid reservoirs), as demonstrated by scanning and transmission electron microscopy analyses. This unique pattern supports the significant difference between total As concentration and the bioaccessible amount. There was a positive correlation between soluble Al (within the Fe-(hydr)oxides phases and minor gibbsite) and As concentration in the soil samples, and a negative correlation with bioaccessible As. Therefore, although Al in the soil is associated with high As levels, it also makes the metalloid less bioaccessible. The risk to human health from As exposure to these soils is low.

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In this work, it was developed three-dimensional (3D) porous hydrogel sponges produced by the freeze-dried process using chitosan polymer functionalized by 11-mercaptoundecanoic acid (MUA). These chitosan-based sponges were used as cationic adsorbents for the removal of anionic methyl orange (MO) dye, simulating a model organic pollutant in aqueous medium. Moreover, these porous 3D constructs were also evaluated as 'antibiotic-free' antibacterial materials against gram-negative and gram-positive bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, respectively, which were used as model pathogens possibly found in contaminated hospital discharges. These 3D hydrogels were comprehensively characterized through morphological methods such as scanning electron microscopy and X-ray micro-computed tomography techniques, combined with FTIR, Raman, and UV-visible spectroscopy analyses. Additionally, the surface area, the degree of swelling, and the adsorption profiles and kinetics of these scaffolds were systematically investigated. The chemically thiolated chitosan (CHI-MUA) hydrogels were successfully produced with a supramolecular polymeric network based on hydrogen bonds, disulfide bonds, and hydrophobic interactions that resulted in higher stability in aqueous medium than hydrogels of pristine chitosan. CHI-MUA exhibited sponge-like three-dimensional structures, with highly interconnected and hierarchical pore size distribution with high porosity and surface area. These architectural aspects of the 3D sponges favoured the high adsorption capacity for MO dye (∼388 mg.g-1) in water with removal efficiency greater than 90% for MO solutions (from 20 mg.L-1-1200 mg.L-1). The adsorption data followed a pseudo-second-order kinetic model and adsorption isotherm analysis and spectroscopy studies suggested a multilayer behaviour with coexistence of adsorbent-adsorbate and adsorbate-adsorbate interactions. Additionally, the in vitro evaluation of toxicity (MTT and LIVE-DEAD® assays) of 3D-sponges revealed a non-toxic response and preliminary suitability for bio-related applications. Importantly, the 3D-sponges composed of chitosan-thiolated derivative proved high antibacterial activity, specificity against P. aeruginosa (model hazardous pathogen), equivalent to conventional antibiotic drugs, while no lethality against S. aureus (reference commensal bacteria) was observed.

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Bioaccessibility (BAC) of fine surface dust (FSD, particle size ≤10 µm) and surface dust samples (particle size ≤250 µm) collected from a gold mining district was used as a tool to determine the portion of arsenic that would be available via simulated lung and gastrointestinal (G.I) fluids. BAC was considered low for both tests (lung 2.7 ±â€¯1%, n = 5 and G.I 3.4 ±â€¯2%, n = 14 for residential surface dust samples). An analytical procedure was developed to further identify arsenic-bearing phases found in FSD samples and analyze the main components that regulate arsenic solubility. Up to five different arsenic-bearing phases were identified among a total of 35 minerals surveyed by scanning electron microscopy-based automated image analysis (Mineral Liberation Analyzer - MLA). Arsenic-bearing Fe oxy-hydroxides and mixed phases comprised the main arsenic phases encountered in FSD samples, thus likely being responsible for regulating arsenic bioaccessibility. Transmission electron microscopy showed that the mixed phases comprised a mix of oriented nanostructure aggregates formed by hematite and goethite entangled with phyllosilicates. The main As-bearing phases identified in FSD samples are similar to those reported in soil samples in the same region. The predominant arsenic-bearing phase encountered in the ore was arsenopyrite, mostly in large particles (>10 µm in size), and therefore unlikely to be found in residential dust. Arsenic intake from both inhalation and ingestion were minimal when compared to total arsenic intake (considering food and water ingestion), which itself was <7% of the value established by the Food and Agriculture Organization of the United Nations Benchmark Dose Lower Confidence Limit (BMDL0.5) of 3.0 µg per kg-1 body weight per day. These results indicated that the relative risks associated with arsenic exposure by inhalation and oral ingestion in this region are low.

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This study assessed various exposure pathways of arsenic and their health risk apportionment to the residents of Paracatu, a gold mining town in Brazil. We measured arsenic concentrations in 50 groundwater and surface town water samples from nearby residences, 38 surface soil dust from residential/commercial dwellings and roadside of Paracatu, and 600 airborne dust samples including PM10 and total suspended particulates (TSP), in additional to a previous reported food survey containing 90 samples from 15 major food categories. For the surface soil dust, bioaccessibility of arsenic as a surrogate of bioavailability was determined using an in vitro physiologically based extraction test (PBET). Rice and bean were found to contain the highest levels of arsenic in which the arsenic speciation was measured whereas the percentages of inorganic arsenic of other food items were taken from the literature for the risk apportionment calculation. The results show that the contribution of inhaled arsenic is ≤3% of the total daily intake, even assuming 100% BAC. The average bioaccessibility of arsenic in the surface soil dust was 3.4 ±â€¯2.0% (n = 17) with a bioaccessible concentration of 4.1 ±â€¯3.7 mg/kg. Food was the main contributor of the daily total intake of arsenic with rice and beans being the most significant ones. The total arsenic intake (ingestion + inhalation) is about 10% of the JECFA BMDL0.5 of 3 µg/kg b.w. per day, and the combined risk based on the cancer slope calculation is similar to the arsenic intake from the consumption of 2 L of water containing 10 µg/L of arsenic, a maximum concentration recommended by WHO. The holistic approach by addressing multiple pathways of exposure is considered a useful tool for health risk assessment throughout the life of mine including mine closure, and can be applied at legacy sites.

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The aim of this work is to evaluate the application of a steel waste, basic oxygen furnace sludge (BOFS), rich in iron, to treat water contaminated with elevated arsenic and sulfate concentrations. In the first step, three doses (10, 60, and 80 g L-1) of BOFS were tested to investigate the removal of As(III) and As(V) (67 mg L-1) and sulfate (3700 mg L-1) separately from an aqueous solution. In the second step, the efficacies of BOFS (10 g L-1) and commercial ZVI (5 g L-1) were compared to simultaneously remove arsenic and sulfate. The pH of the feed solution was adjusted to 2.5 and monitored during the experiment. The use of BOFS achieved arsenic removal up to 92% and sulfate removal of nearly 40% after 72 h of contact time. Use of BOFS also increased the solution pH to 12. Similar removal levels were achieved with both BOFS and ZVI. These results confirm the potential application of BOFS to remove high arsenic and sulfate concentrations from acidic solutions. The data obtained here should be used as a basis for further studies on the remediation of acid mine drainage with high concentrations of arsenic and sulfate using an abundant and low-cost steel waste.

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The human health risk associated with arsenic in food in Southeast Brazil was quantified. Based on the most commonly consumed food types in the Brazilian diet, the maximum inorganic As (iAs) daily intake from food (0.255 µg kg-1 body weight per day) is approximately 9% of the Benchmark Dose Lower Limit (BMDL0.5) of 3 µg kg-1 body weight per day set by the World Health Organization (WHO) and Food and Agriculture Organization (FAO) Joint Expert Committee in Food Additives (JECFA). When water is included, the contribution of food to the total intake varies from 96.9% to 39.7%. Rice and beans, the main Brazilian staple food, contribute between 67 and 90% of the total As intake from food (46-79% from rice and 11-23% from beans). The substantial contribution of beans to total As food intake is reported for the first time. The broad range of As concentrations in rice and beans highlights the variable and potentially large contribution of both to As food intake in places where diet consists largely of these two food categories.

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Resumo Malformação congênita, segunda maior causa de mortalidade infantil, constitui condição de vulnerabilidade importante na gravidez, que repercute desfavoravelmente na saúde mental da gestante. Objetivou-se estudar o impacto do momento do diagnóstico de malformação congênita sobre a saúde mental de 66 gestantes em atendimento pré-natal. Para isso, as participantes responderam ao Questionário "Momento da notícia", o qual identifica variáveis psicossociais relativas ao momento do diagnóstico da deficiência, e as Escalas Beck, para avaliar sinais e sintomas de ansiedade (Beck Anxiety Inventory) e depressão (Beck Depression Inventory). Todas receberam a notícia através de um médico, sendo 19 no segundo trimestre gestacional. Quatorze consideraram a transmissão do diagnóstico apropriada. No entanto, quando a notícia ocorreu no primeiro trimestre, tanto indicadores de ansiedade (p = 0,0009) quanto de depressão (p = 0,000004) se associaram ao momento da comunicação do diagnóstico; diferente de quando a gestante era comunicada no segundo trimestre, ao qual esteve associado somente os indicadores de depressão (p = 0,0462). Discute-se indicadores de ansiedade e depressão na gestação relacionados ao diagnóstico de malformação congênita como agravantes da vulnerabilidade física e psíquica durante a gestação.

Abstract Congenital malformation, the second largest cause of infant mortality, is an important cause of vulnerability during pregnancy, and it has an unfavorable effect on the mental health of pregnant woman. The objective of this study was to investigate the impact of the moment of diagnosis of congenital malformation on the mental health of 66 pregnant women receiving prenatal care. The participants answered the questionnaire "Momento da notícia" (Moment of diagnosis), which identifies psychosocial variables related to the moment of diagnosis. The Beck Scales were also used to assess signs and symptoms of anxiety (Beck Anxiety Inventory) and depression (Beck Depression Inventory). All participants were given the diagnosis by a physician, and 19 were notified during the second trimester of pregnancy. The diagnosis communication was considered adequate by fourteen participants. However, when the diagnosis was notified during the first trimester of pregnancy it was associated with indicators of anxiety (p = 0.0009) and depression (p = 0.000004). Different results were found when the mother was notified during the second trimester, when only the indicators of depression were associated to the diagnosis received (p = 0.0462). The present study addressed the indicators of anxiety and depression during pregnancy associated to the diagnosis of congenital malformation as risk factors for the physical and psychological vulnerability during this period.

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