Efecto de la incorporación de enmiendas carbonosas como alternativa para disminuir la toxicidad de sedimentos provenientes de la parte baja de la Cuenca Matanza-Riachuelo (Argentina)

Abstract

[ES] La necesidad de dragar determinados ríos para permitir la navegación en ellos ha causado controversia acerca del destino final de esos sedimentos extraídos, especialmente cuando los mismos poseen elevadas cargas orgánicas o contaminantes. Mediante una caracterización fisicoquímica y diversos bioensayos se evaluará la toxicidad de sedimentos provenientes de un sector perteneciente a la cuenca Matanza-Riachuelo, que se conoce que posee elevada contaminación.

Con el fin de optimizar parámetros de un proceso de fitoremediación, se estudiará el efecto de la incorporación de dos tipos de carbones (vegetal y activado comercial) en distintas proporciones (10% y 20%). A escala laboratorio se realizarán ensayos de germinación y de elongación radicular así como los ensayos a nivel de plántula para detectar la toxicidad presente en ese sector de la cuenca así como la capacidad de fitoacumulación de metales pesados en los sedimentos extraídos. Se espera que este estudio contribuya a establecer las pautas del proceso de fitorremediación y comprobar su repercusión en el crecimiento de la especie vegetal.

[EN] The need to dredge certain rivers to allow navigation has caused controversy about the final disposition of the extracted sediments, especially when they have high organic or polluting loads. In the case of Argentina, the lack of national legislation enables the unregulated disposal of sediments that severely affects the populations of lower resources that settle in the surrounding areas, such as the Matanza-Riachuelo basin (CMR). Through a physicochemical characterization and diverse bioassays, the toxicity of sediments from the lower part of the CMR, known to have high metallic contamination, was evaluated. In order to optimize the parameters of a phytostabilization scheme to revegetate a site contaminated with heavy metals, the effect of the incorporation of two types of amendments (charcoal and commercial activated carbon) in different proportions (10% and 20%) was studied. With the defined treatments, germination and root elongation tests, earthworm escape tests and seedling level tests were carried out as tools to compare the toxicity of the amended sediments with that of the pure sediment. As a result of the experimental section, it was observed that the treatment of commercial activated carbon in the highest dose (CA20%) would be an amendment with potential to decrease the toxicity of the substrate and allow revegetation of the site. In this way, it would be a useful strategy to improve the conditions of the sediment, which would make it possible to establish a vegetation cover and thus reduce the exposure risks of the surrounding population.