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1.
Environ Res ; 210: 112940, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35182597

RESUMO

Neuropsychological alterations have been identified in populations heavily exposed to metals with neurotoxic potential, such as manganese (Mn). This study examined the associations between Mn environmental exposure in school-aged children and executive functions, using structural equation modeling. Children, aged between 7 and 12 years (N = 181), were recruited from four elementary schools located in a region that is under the influence of atmospheric emissions from a ferro-manganese alloy plant in the municipality of Simões Filho, Bahia, Brazil. The following cognitive functions were evaluated: Intelligence, Inhibitory Control, Cognitive Flexibility, Verbal and Design Fluency, Verbal and Visual Working Memory and Attention. We performed structural equation modeling to identify the following executive functions latent variables: working memory, inhibitory control and cognitive flexibility. We further analyzed the relations between executive functions and Mn measured in hair (MnH) and toenails (MnTn) with linear mixed models, after controlling for co-variables. A positive effect at the individual level on working memory, inhibition control and cognitive flexibility was observed with MnTn after controlling for co-variables, but no association was found with MnH levels. However, children attending school most environmentally exposed to Mn emissions, which had the highest rate of Mn dust deposition, had the poorest scores on working memory. These findings suggest both benefits and risk of Mn on children's cognitive development.


Assuntos
Função Executiva , Manganês , Criança , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Humanos , Íons/análise , Íons/farmacologia , Manganês/análise , Manganês/toxicidade , Memória de Curto Prazo , Análise Multinível
2.
Environ Res ; 167: 66-77, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30007874

RESUMO

Excessive exposure to Mn can lead to its accumulation in the brain with neurotoxic consequences. In children, elevated Mn has been associated with deficits in certain neuropsychological domains such as cognition, motor function, memory and attention, and in some instances, hyperactivity and behavioral problems. The aim of this study was to evaluate behavioral effects in school-aged children living near a ferro-manganese alloy plant and examine their association with Mn exposure. Occipital hair, toenails and blood samples were collected from 225 children (7-12 years old) enrolled in four elementary schools with different levels of exposure to Mn, based on dust Mn deposition rates. Full data set collection was completed and run from 165 children. Mn in hair (MnH), toenails (MnTn), blood (MnB) and blood lead levels (PbB) were determined by graphite furnace atomic absorption spectrometry. Children's behavior was assessed with the Child Behavior Check List (CBCL) reported by parents. Median levels and range of MnH, MnT and MnB were, respectively, 0.73 µg/g (0.16-8.79), 0.84 µg/g (0.15-9.29) and 8.98 µg/L (1.51-40.43). Median and range of PbB were 1.2 µg/dL (0.2-15.6). MnH and MnB were not associated with any scale of the CBCL behavior scores. We found a positive association between logMnTn and raw total CBCL score (ß = 10.17, p = 0.034), adjusting for sex, age, maternal IQ and logPbB. Analyses using Generalized Additive Model showed non-linear associations between MnTn and externalizing behavior (p = 0.035), as well as with the related subscales: aggressive behavior (p = 0.045) and rule-breaking behavior (p = 0.024). Further positive associations were observed between MnTn and thought problems (p = 0.031) and social problems (p = 0.027). These findings corroborate previous studies showing an association between Mn exposures and externalizing behavior. Our results suggest that toenail Mn, as a biomarker of environmental exposure, is associated with disruptive behavior in children living near a ferro-manganese alloy plant.


Assuntos
Agressão , Poluentes Atmosféricos , Manganês , Comportamento Problema , Poluentes Atmosféricos/toxicidade , Criança , Exposição Ambiental , Feminino , Humanos , Ferro , Chumbo , Masculino , Manganês/toxicidade
3.
Environ Pollut ; 236: 1004-1013, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29287923

RESUMO

Previously, we showed that manganese (Mn) levels in settled dust in elementary schools increased at a rate of 34.1% per km closer to a ferro-manganese alloy plant in the rainy season. In this study, we investigated how this environmental pollution indicator varied in the dry season and if there was an association with Mn biomarker levels in school-aged children. Dust samples were collected with passive samplers (disposable Petri dishes) placed in interior and exterior environments of 14 elementary schools. Occipital hair, toenails and blood samples were collected from 173 students aged 7-12 years from three of these schools, with varying distance from the industrial plant. Mn and lead (Pb) levels were measured by graphite furnace atomic absorption spectrometry. Mn concentration geometric means (GM) in dust fall accumulation in interior environments of schools located at 2, 4, 6 and > 6 km-radii from the plant were 2212, 584, 625 and 224 µg Mn/m2/30 days, respectively. The modelled rate of change of dust Mn levels decreases by 59.8% for each km further from the plant. Pb levels in settled dust varied between 18 and 81 µg/m2/30 days with no association with distance from the plant. Blood lead levels median (range) were 1.2 µg/dL (0.2-15.6), of which 97.8% were <5 µg/dL. Mn in hair and toenails were 0.66 µg/g (0.16-8.79) and 0.86 µg/g (0.15-13.30), respectively. Mn loading rates were positively associated with log MnH (ß = 1.42 × 10-5, p < 0.001) after adjusting for children's age; and also with log MnTn (ß = 2.31 × 10-5, p < 0.001) independent of age. Mn loading rates explained 18.5% and 28.5% of the variance in MnH and MnTn levels, respectively. School-aged children exposure to Mn, independently of age, increases significantly with school proximity to the ferro-manganese alloy plant.


Assuntos
Biomarcadores/análise , Poeira/análise , Exposição Ambiental , Chumbo/análise , Manganês/análise , Criança , Feminino , Cabelo/química , Humanos , Íons/análise , Ferro/análise , Masculino , Unhas/química , Instituições Acadêmicas , Estações do Ano , Espectrofotometria Atômica
4.
Artigo em Inglês | MEDLINE | ID: mdl-30384464

RESUMO

Studies have demonstrated that, for urban children, dust represents the main exposure to sources of metals like lead (Pb) and manganese (Mn). We aimed to investigate the exposure to these metals and their association with intellectual deficit in children living in an industrial region. This cross-sectional study recruited volunteers from four elementary schools in the town of Simões Filho, Brazil. We evaluated 225 school-aged children (7⁻12 years) for blood lead (PbB) and manganese hair (MnH) and toenails (MnTn) by graphite furnace atomic absorption spectrometry. Child and maternal IQs were estimated using the Wechsler Abbreviated Scale for Intelligence (WASI). Median and range PbB were 1.2 (0.3⁻15.6) µg/dL. MnH and MnTn medians (ranges) were 0.74 (0.16⁻8.79) µg/g and 0.85 (0.15⁻13.30) µg/g, respectively. After adjusting for maternal IQ, age and Mn exposure, child IQ drops by 8.6 points for a 10-fold increase in PbB levels. Moreover, an effect modification of Mn co-exposure was observed. In children with low MnTn, association between Pb and child IQ was not significant (ß = -6.780, p = 0.172). However, in those with high MnTn, the association was increased by 27.9% (ß = -8.70, p = 0.036). Low Pb exposure is associated with intellectual deficit in children, especially in those with high MnTn.


Assuntos
Poeira/análise , Exposição Ambiental/efeitos adversos , Inteligência/fisiologia , Chumbo/efeitos adversos , Manganês/efeitos adversos , Estudantes/estatística & dados numéricos , Encefalopatias , Brasil , Criança , Estudos Transversais , Exposição Ambiental/análise , Monitoramento Ambiental , Feminino , Cabelo/química , Humanos , Testes de Inteligência , Chumbo/sangue , Masculino , Manganês/sangue , Intoxicação por Manganês/epidemiologia , Instalações Industriais e de Manufatura , Unhas/química , Instituições Acadêmicas , População Urbana/estatística & dados numéricos
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