The contamination of soil and water by metals and metalloids is recurrent in the world and has threatened the health of millions of people. Among the potentially toxic elements (PTEs), arsenic (As) stands out. Part of the origin of As contamination is related to mining activity, due to the production of large quantities of tailings, which are an important source of PTEs. In situ remediation techniques have been used to recover the contaminated areas through the addition of organic additives such as biochar. The biochar can restore the quality of the contaminated soil by promoting the immobilization of PTEs and, thus, reducing the risks associated with these pollutants. The effect of biochar is linked to the temperature of pyrolysis and the biogeochemistry of the environment where it will be applied. Changes in the biogeochemical processes that govern As dynamics, such as redox reaction, presence of biogenic oxides and natural organic matter, can affect the potential use of biochar. In this project, we intend to evaluate i) the influence of the addition of biochar and the wetting and drying cycles on the availability and distribution of As species in the sediment; ii) the influence of pyrogenic organic matter dissolved in the sorption of As in biogenic iron oxide (BIOS); and iii) the influence of pyrolysis temperature on the formation of the organomineral complex. With our results we hope to elucidate the effect of pyrogenic carbon on the availability of As under redox conditions and in the presence of BIOS.
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