Computed tomography assessment of soil and sediment porosity modifications from exposure to an acid copper sulfate solution
Por:
Ziegler-Rivera F.R.A., Prado, Blanca, Gastelum-Strozzi, Alfonso, Marquez, Jorge, Mora, Lucy, Robles, Agustin, Gonzalez, Blanca
Publicada:
1 jun 2021
Resumen:
Mine spills, like acidified copper sulfate solutions, are known for the
contaminating effects in soils and sediments, chemically altering them.
However, little is known about the physical effects of this process.
Therefore, we investigated the response of the soil and sediments
porosity to the infiltration of an acid copper sulfate solution (ACSS)
generated for mining purposes. The samples used consisted of
intact/undisturbed soil and sediment columns extracted in the upper Rio
Sonora basin, located in northern Mexico in the state of Sonora, where
extensive mining activity has been carried out since 1880's. Three
infiltration and solute transport experiments were conducted to monitor
the changes in pH, electrical conductivity (EC) and flow velocity in the
collected leachate. Computed X-Ray Tomography was used to
microscopically analyze a series of soil porosity images before and
after each irrigation with ACSS. We observed that the interactions of
soil/sediment matrices with ACSS, promoted changes in the flow velocity,
which can be related to the modification of the original porosity. The
computed X-Ray Tomography showed that the passage of the ACSS through
the soil and sediment caused different effects in both matrices: (1) a
decrease in the number and size of pores in the soil column and (2) an
increase in the number and size of pores in the sediment, showing that
the passage of the solution in both matrices had opposite effects,
causing a decrease in soil porosity as a possible response to the
presence of suspended particles related to the ACSS, and the formation
of new minerals that caused the sealing of pores in the soil and the
erosion of the walls of the pores in the sediment creating preferential
flows. This work shows that soils and sediments that interact with the
ACSS are not only affected chemically, but also that there may appear
modifications in porosity, leading to study also the physical effects
that occur in sites affected by this type of events.
Filiaciones:
Posgrado en Ciencias de La Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior S/N, Mexico City, Mexico
Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior S/N, Mexico City, Mexico
Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior S/N, Mexico City, Mexico
Departamento de Ciencias Del Agua y Del Medio Ambiente, Instituto Tecnológico de SonoraSonora, Mexico
CONACYT, Insurgentes Sur 1582, Crédito Constructor, Benito Juárez, CP. 03940, CDMX, Mexico
Estación Regional Del Noroeste, IGL, Universidad Nacional Autónoma de México, Colosio y Madrid S/n, CP. 83000, Hermosillo, Sonora, Mexico
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