RESUMO
A growing body of literature reports the need for an integrated approach to study the effects of the physical environment on the neurodevelopment of children. Assessment of the true neurotoxicity of pollutants cannot be performed separately from the ecological and multidimensional contexts in which they act. In this study, from the perspective of the Bronfenbrenner's bioecological model, a conceptual model was developed that encompasses the social and biological characteristics of children from the gestational period to childhood, considering exposure to toxic metals. First, we present the toxicity of the main metals and some concept notions that we used in our framework, such as social and structural determinants of health, allostatic load, embodiment, and epigenetic concepts. Then, the main aspects of the Bronfenbrenner's bioecological model, which allow integration of the gene-social relationship in addition to the physical environment, where these metals act, are explained. Finally, we present and discuss the conceptual framework showing how, in real life, biological and social factors may together influence the neurodevelopment of children. Although this model is based on a group of contaminants, it opens new horizons on how environmental sciences, such as neurotoxicology and environmental epidemiology, can articulate with the theoretical models from human sciences to provide a broader approach to study the effects on human neurodevelopment.
Assuntos
Meio Ambiente , Poluentes Ambientais , Criança , Humanos , Brasil , Poluentes Ambientais/toxicidade , Relações InterpessoaisRESUMO
A growing body of literature reports the need for an integrated approach to study the effects of the physical environment on the neurodevelopment of children. Assessment of the true neurotoxicity of pollutants cannot be performed separately from the ecological and multidimensional contexts in which they act. In this study, from the perspective of the Bronfenbrenner's bioecological model, a conceptual model was developed that encompasses the social and biological characteristics of children from the gestational period to childhood, considering exposure to toxic metals. First, we present the toxicity of the main metals and some concept notions that we used in our framework, such as social and structural determinants of health, allostatic load, embodiment, and epigenetic concepts. Then, the main aspects of the Bronfenbrenner's bioecological model, which allow integration of the gene-social relationship in addition to the physical environment, where these metals act, are explained. Finally, we present and discuss the conceptual framework showing how, in real life, biological and social factors may together influence the neurodevelopment of children. Although this model is based on a group of contaminants, it opens new horizons on how environmental sciences, such as neurotoxicology and environmental epidemiology, can articulate with the theoretical models from human sciences to provide a broader approach to study the effects on human neurodevelopment.
Uma crescente literatura relata a necessidade de uma abordagem integrada para estudar os efeitos do ambiente físico no neurodesenvolvimento de crianças. A avaliação da verdadeira neurotoxicidade dos poluentes não pode ser realizada separadamente dos contextos ecológicos e multidimensionais em que atuam. Neste estudo, sob a perspectiva do modelo bioecológico de Bronfenbrenner, um modelo conceitual foi desenvolvido para abranger as características sociais e biológicas das crianças desde o período gestacional até a infância, considerando a exposição a metais tóxicos. Primeiro, apresentamos a toxicidade dos principais metais e algumas noções conceituais que utilizamos em nossa abordagem, tais como determinantes sociais e estruturais da saúde, carga alostática, incorporação e conceitos epigenéticos. Em seguida, explicamos os principais aspectos do modelo bioecológico de Bronfenbrenner, que permitem a integração da relação gene-social, além do ambiente físico, onde esses metais atuam. Por fim, apresentamos e discutimos o quadro conceitual mostrando como, na realidade, fatores biológicos e sociais podem, em conjunto, influenciar o neurodesenvolvimento das crianças. Embora esse modelo seja baseado em um grupo de contaminantes, ele abre novos horizontes sobre como as ciências ambientais, como a neurotoxicologia e a epidemiologia ambiental, podem dialogar com os modelos teóricos das ciências humanas para ter uma abordagem mais ampla ao estudar os efeitos no neurodesenvolvimento humano.
Una creciente literatura informa la necesidad de un enfoque integrado para estudiar los efectos del entorno físico en el neurodesarrollo de los niños. La evaluación de la verdadera neurotoxicidad de los contaminantes no puede llevarse a cabo por separado de los contextos ecológicos y multidimensionales en los que actúan. En este estudio, desde la perspectiva del modelo bioecológico de Bronfenbrenner, se desarrolló un modelo conceptual para abarcar las características sociales y biológicas de los niños desde el período gestacional hasta la infancia, considerando la exposición a metales tóxicos. Primero, presentamos la toxicidad de los principales metales y algunas nociones conceptuales que utilizamos en nuestro enfoque, como los determinantes sociales y estructurales de la salud, la carga alostática, la incorporación y los conceptos epigenéticos. A continuación, explicamos los principales aspectos del modelo bioecológico de Bronfenbrenner, que permiten la integración de la relación gen-social, además del entorno físico, donde actúan estos metales. Finalmente, presentamos y discutimos el marco conceptual que muestra cómo, en realidad, los factores biológicos y sociales pueden, en conjunto, influir en el neurodesarrollo de los niños. Aunque este modelo se basa en un grupo de contaminantes, abre nuevos horizontes sobre cómo las ciencias ambientales, como la neurotoxicología y la epidemiología ambiental, pueden dialogar con los modelos teóricos de las ciencias humanas para adoptar un enfoque más amplio al estudiar los efectos sobre el neurodesarrollo humano.
RESUMO
Previous studies have shown elevated airborne manganese (Mn) in villages adjacent to a Mn alloy production plant in Brazil and negative associations between biomarkers of Mn and children's cognition and behavior. Since small Mn particles may be carried for long distances, we measured manganese (Mn) and lead (Pb) dust fall accumulation in 15 elementary schools, located between 1.25 and 6.48km from the plant in the municipality of Simões Filho, Bahia, Brazil. Passive samplers (polyethylene Petri dishes) were set in interior and exterior environments. After 30 days, the samplers' content was solubilized with diluted nitric acid and Mn and Pb levels were analyzed by electrothermal absorption spectrometry. The overall geometric mean and range of Mn and Pb accumulation in dust fall (loading rates) were 1582µg Mn/m(2)/30 days (37-37,967) and 43.2µg Pb/m(2)/30 days (2.9-210.4). A logarithmic decrease in interior and exterior Mn loading rates was observed with distance from the ferro-manganese alloy plant. Multiple regression analyses of log-transformed Mn loading rate within the schools showed a positive association with Mn levels in outdoor dust, a negative association with distance from the plant; as well, wind direction (downwind>upwind) and school location (urban>rural) entered significantly into the model. For the interior school environments, located within a 2-km radius from the plant, loading rate was, on average, 190 times higher than the Mn levels reported by Gulson et al., (2014) in daycare centers in Sydney, Australia, using a similar method. Pb loading rates were not associated with distance from the plant and were lower than the rates observed in the same daycare centers in Sydney. Our findings suggest that a significant portion of the children in this town in Brazil may be exposed to airborne Mn at concentrations that may affect their neurodevelopment.
