Estimación del riesgo ecológico y a la salud humana del mercurio en una zona de manglar del estuario La Puntilla, provincia de El Oro, sur del Ecuador
DOI:
https://doi.org/10.25268/bimc.invemar.2020.49.1.775Palabras clave:
índice de riesgo ecológico, mercurio, Anadara tuberculosa, ecosistema de manglarResumen
El presente estudio se centra en la evaluación de los niveles de concentración de mercurio total y la estimación del riesgo ecológico (Er), el índice de riesgo ecológico (RI) y el coeficiente de riesgo tóxico o peligro (HQ) para la salud humana en un área de manglar junto a las desembocaduras de los ríos Chaguana y Siete, en el estuario de La Puntilla en el sur de Ecuador. Para la determinación de Er, RI y HQ, identificamos tres indicadores de contaminación por mercurio: sedimentos, raíz de mangle y tejido blando del bivalvo Anadara tuberculosa. En el área de manglar que bordea la desembocadura del río Chaguana, las concentraciones de mercurio fluctuaron entre 0,11±0,06 mg/kg en sedimentos, 0,06±0,01mg/kg en raíz de mangle, con una consistente presencia de A. tuberculosa, pero solo una muestra del bivalvo registró un nivel de 0,034 mg/kg de mercurio. En contraste, en el área de manglar adyacente a la desembocadura del río Siete, las concentraciones de mercurio oscilaron entre 0,77±0,42 mg/kg en sedimentos y 0,15±0,12 mg/kg en la raíz de manglar, siendo imperceptible la presencia de A. tuberculosa. Los resultados del análisis de riesgo indicaron que en la desembocadura del río Chaguana, el Er y el índice de RI se colocaron en la categoría “baja”. En contraste, en la desembocadura del río Siete, el Er resultó “alto” y RI resultó “moderado”. El riesgo potencial para la salud humana fue bajo, en consistencia con el valor de HQ < 1 que considera el consumo de A. tuberculosa y el contacto dérmico a través de sedimentos; sin embargo, la escasa presencia del bivalvo en la desembocadura del río Siete es de preocupación.
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