RESUMO
The objective of this study was to evaluate, through changes in the gills and livers of Sciades herzbergii, the environmental contamination to which estuarine organisms are exposed in two areas in São Marcos Bay - MA. Two collection areas located in São Marcos Bay were selected for this study: A1, an area close to the Port Complex, and A2, an area on Caranguejos Island (included in the Environmental Protection Area of Baixada Maranhense). Collections were carried out during rainy and dry periods. Sediments (for trace element analyses), surface water (for physico-chemical analyses), and specimens of S. herzbergii (for biometric measurements and identification of branchial and hepatic histopathology) were collected. Physico-chemical parameters (pH, dissolved oxygen, temperature and salinity) were within limits established by Brazilian legislation. Arsenic (in A1) and nickel (in A1 and A2) were above the legal standards in both periods. The highest percentage of histological alterations in the gills (aneurysms, lamellar fusion and detachment of the epithelium) occurred in the port area, in the rainy (93%) and dry (74%) periods. Liver alterations (melanomacrophage centers and necrosis) occurred only in specimens from the same area, in the rainy (41%) and dry (36%) periods. The highest histological indices of gill and liver changes were recorded in A1. This result was further supported by the total HI value of the lesions, which was higher in the port area compared to A2 (less impacted area), suggesting that the environmental conditions in that location are less favorable for the well-being of these organisms. Permanent environmental monitoring of the area is necessary to control environmental impacts efficiently.
Assuntos
Peixes-Gato , Oligoelementos , Animais , Brasil , Brânquias , FígadoRESUMO
Abstract The objective of this study was to evaluate, through changes in the gills and livers of Sciades herzbergii, the environmental contamination to which estuarine organisms are exposed in two areas in São Marcos Bay - MA. Two collection areas located in São Marcos Bay were selected for this study: A1, an area close to the Port Complex, and A2, an area on Caranguejos Island (included in the Environmental Protection Area of Baixada Maranhense). Collections were carried out during rainy and dry periods. Sediments (for trace element analyses), surface water (for physico-chemical analyses), and specimens of S. herzbergii (for biometric measurements and identification of branchial and hepatic histopathology) were collected. Physico-chemical parameters (pH, dissolved oxygen, temperature and salinity) were within limits established by Brazilian legislation. Arsenic (in A1) and nickel (in A1 and A2) were above the legal standards in both periods. The highest percentage of histological alterations in the gills (aneurysms, lamellar fusion and detachment of the epithelium) occurred in the port area, in the rainy (93%) and dry (74%) periods. Liver alterations (melanomacrophage centers and necrosis) occurred only in specimens from the same area, in the rainy (41%) and dry (36%) periods. The highest histological indices of gill and liver changes were recorded in A1. This result was further supported by the total HI value of the lesions, which was higher in the port area compared to A2 (less impacted area), suggesting that the environmental conditions in that location are less favorable for the well-being of these organisms. Permanent environmental monitoring of the area is necessary to control environmental impacts efficiently.
Resumo O objetivo deste estudo foi avaliar, por meio de alterações nas brânquias e fígados de Sciades herzbergii, a contaminação ambiental a que os organismos estuarinos estão expostos em duas áreas da Baía de São Marcos - MA. Para este estudo foram selecionadas duas áreas de coleta localizadas na Baía de São Marcos: A1, área próxima ao Complexo Portuário, e A2, área na Ilha dos Caranguejos (incluída na Área de Proteção Ambiental da Baixada Maranhense). As coletas foram realizadas nos períodos chuvoso e seco. Foram coletados sedimentos (para análises de elementos traço), águas superficiais (para análises físico-químicas) e espécimes de S. herzbergii (para medidas biométricas e identificação de histopatologia branquial e hepática). Os parâmetros físico-químicos (pH, oxigênio dissolvido, temperatura e salinidade) estiveram dentro dos limites estabelecidos pela legislação brasileira. Arsênio (em A1) e níquel (em A1 e A2) estiveram acima dos padrões legais em ambos os períodos. A maior porcentagem de alterações histológicas nas brânquias (aneurismas, fusão lamelar e descolamento do epítélio) ocorreu na área portuária, nos períodos chuvoso (93%) e seco (74%). As alterações hepáticas (centros de melanomacrófagos e necrose) ocorreram apenas nos espécimes dessa mesma área, nos períodos chuvoso (41%) e seco (36%). Os maiores índices histológicos de alterações branquiais e hepáticas foram registrados em A1. Esse resultado foi ainda corroborado pelo valor de IH total das lesões, que foi maior na área portuária em comparação com A2 (área menos impactada), sugerindo que as condições ambientais naquele local são menos favoráveis ao bem-estar desses organismos. O monitoramento ambiental permanente da área é necessário para controlar os impactos ambientais de forma eficiente.