Determinación de metales pesados (cd y pb) en moluscos bivalvos de interés comercial de cuatro esteros del Golfo de Guayaquil.
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2010
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En el presente trabajo se ha empleado dos especies de moluscos bivalvos (Mytella strigata y Ostrea columbiensis) de gran importancia tanto para el comercio como para el consumo interno en las comunidades asentadas en el Golfo de Guayaquil, con la finalidad de establecer una línea base de las concentraciones de cadmio y plomo encontradas en estos organismos y confirmar su importancia como bioindicadores de contaminación por estos metales. Se realizaron cuatro muestreos de septiembre a diciembre del 2009 en cuatro esteros del Golfo de Guayaquil interior: Chupadores Grande, Chupadores Chico, Las Loras y Las Cruces, colectándose un total de 200 individuos por especie, en los cuales se determinó las concentraciones de cadmio y plomo por Espectrofotometría de Absorción Atómica. La especie que presentó mayor concentración de cadmio fue el ostión, presentando valores promedio de 8.02 (Chupadores Chico), 6.25 (Chupadores grande), 8.24 (Las Loras) y 7.49 (Las Cruces) expresados en ppm en peso seco. Dentro del marco del estudio la mayor concentración de plomo fue encontrada en los ostiones del estero Las Cruces con 5.03 ppm/peso seco, seguido de los ostiones del estero Chupadores Chico a los que se les cuantificó 1.96 ppm/peso seco. En los esteros Chupadores Grande y Las Loras, las mayores concentraciones de plomo se encontraron en mejillones con 1.98 y 1.75 ppm/peso seco, respectivamente. Los valores registrados en ppm de peso seco fueron transformados a peso húmedo para comparación con los límites máximos permitidos por la Comisión Europea (2006), esto indicó que el cadmio en ostiones sobrepasó dichos niveles, por lo que se considera un riesgo el consumo de dichos organismos. Las concentraciones de cadmio y plomo en agua se encontraron bajo los límites permisibles de la legislación ecuatoriana en los cuatro esteros muestreados, sin embargo en el sedimento existe diferencia entre las concentraciones de dichos elementos, en el caso del cadmio los valores van desde 0.82 a 1.82 ppm/peso seco y en el plomo los valores se encuentran desde 8.35 hasta l1.55 ppm/peso seco.
In the present work two species of bivalve molluscs (Mytella strigata and Ostrea columbiensis) of great importance both for trade and domestic consumption in the communities located in the Gulf of Guayaquil were used in order to establish a baseline concentration of cadmium and lead found in these organisms and confirm their relevance as bioindicators of pollution by these metals. From September to December 2009, four surveys were performed in four estuaries in the inner part of the Gulf of Guayaquil: Chupadores Grandes, Chupadores Chico, Las Loras and Las Cruces, a total of 800 individuals per species were collected and the concentration of cadmium and lead Lead by Atomic Absorption Spectrophotometry was established. The specie showing the highest concentration of cadmium was the oyster, with values averaging 8.02 (Chupadores Chico), 6.25 (Chupadores Grande), 8.24 (Las Loras) and 7.49 (Las Cruces) expressed in ppm dry weight. Within the framework of the study the highest concentration of lead was found in oysters from the Las Cruces estuary with 5.03 ppm / dry weight, followed by oysters from Chupadores Chico estuary with 1.96 ppm / dry weight. In the Chupadores Grande and Las Loras estuaries, the highest concentrations of lead were found in mussels and 1.98 and 1.75 ppm / dry weight, respectively. The values recorded in ppm dry weight were transformed into wet weight for comparison with the maximum permitted by the European Commission (2006), this indicated that cadmium in oysters exceeded those levels, therefore consumption of this organisms is considered a risk for human health. The concentrations of cadmium and lead were within the permissible limits of the Ecuadorian legislation in the four estuaries sampled, however in the sediment differences between the concentrations of these elements were found, in the case of cadmium the values ranging from 0.82 to 1.82 ppm / dry weight and lead values from 8.35 to l1.55 ppm / dry weight.
In the present work two species of bivalve molluscs (Mytella strigata and Ostrea columbiensis) of great importance both for trade and domestic consumption in the communities located in the Gulf of Guayaquil were used in order to establish a baseline concentration of cadmium and lead found in these organisms and confirm their relevance as bioindicators of pollution by these metals. From September to December 2009, four surveys were performed in four estuaries in the inner part of the Gulf of Guayaquil: Chupadores Grandes, Chupadores Chico, Las Loras and Las Cruces, a total of 800 individuals per species were collected and the concentration of cadmium and lead Lead by Atomic Absorption Spectrophotometry was established. The specie showing the highest concentration of cadmium was the oyster, with values averaging 8.02 (Chupadores Chico), 6.25 (Chupadores Grande), 8.24 (Las Loras) and 7.49 (Las Cruces) expressed in ppm dry weight. Within the framework of the study the highest concentration of lead was found in oysters from the Las Cruces estuary with 5.03 ppm / dry weight, followed by oysters from Chupadores Chico estuary with 1.96 ppm / dry weight. In the Chupadores Grande and Las Loras estuaries, the highest concentrations of lead were found in mussels and 1.98 and 1.75 ppm / dry weight, respectively. The values recorded in ppm dry weight were transformed into wet weight for comparison with the maximum permitted by the European Commission (2006), this indicated that cadmium in oysters exceeded those levels, therefore consumption of this organisms is considered a risk for human health. The concentrations of cadmium and lead were within the permissible limits of the Ecuadorian legislation in the four estuaries sampled, however in the sediment differences between the concentrations of these elements were found, in the case of cadmium the values ranging from 0.82 to 1.82 ppm / dry weight and lead values from 8.35 to l1.55 ppm / dry weight.
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CADMIO, CONTAMINACIÓN, METALES PESADOS, MEJILLONES, PLOMO, OSTIONES