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The Mojana region is one of the most important ecosystems in Colombia, however, several authors have demonstrated the degree of mercury contamination in their aquatic systems (Pinedo, Marrugo, & Díez, 2015). Being the sediment analysis one of the most used pollution indicators today, because its characterization and speciation can help to understand conditions such as the presence, bioavailability mobility and toxicity of the metal (Ana Teresa Reis, Davidson, Vale, & Pereira, 2016). Therefore, the present investigation describes the application of thermal desorption as a technique for direct speciation of low-cost and rapid mercury; therefore, 3 sediment samples from the Mojana region were analyzed, using a direct mercury analyzer DMA80. The temperatures used were 100, 150, 200, 250, 300, 400, 450, 500, 600, 650 ° C. Sequential extraction was also performed using the BLOOM method, physicochemical parameters were evaluated. The results showed that the sediments in general have an acidic pH ranging between 3.32 and 5.08, it was also found that the% MO was 2.0, 2.77 and 1.05% for Quebradona, Encaramada and Caimanera swamp respectively, and the redox potential is of character reducer. The total concentrations of Hg for the different sampling points were: Quebradone (137.75 ng / gr); Perched (79.76 ng / gr) Caimanera Swamp (132.70 ng / gr), for thermodesorption it was obtained that about 90% of the mercury is linked to HgCl2.

In Colombia there are several areas contaminated with heavy metals, one of these is located in the San Juan de Assisi corregimiento, municipality of Puerto LibertadorCórdoba, called the El Alacrán mine, where its main activity is the artisanal exploitation of vein gold with mercury amalgam. This has led to contamination of soils and ecosystems in the area due to the mining waste generated by this activity, including mercury (Hg) and copper (Cu). This situation has become a threat to human and environmental health, because in this area natural resources (water and soils) are used for agricultural and livestock purposes, their productivity and health depend on the state in which they are located. The phytoremediation technique is very useful in the face of this problem, as it can remedy soils contaminated with heavy metals. Which is why the objective of this study was to evaluate the fitorremediation process with Jatropha curcas L, whit the purpose of obtaining reliable, evidence-based information under real field conditions. For this purpose, physicochemical soil analyses were performed at the beginning of the process and 18 months after the species was established. Metal concentrations in soils and plants were also determined. The direct method of thermal decomposition was used for mercury analysis, using DMA-80 equipment and the flame atomic absorption spectrometry measurement methodology was used for copper analysis. The results showed that Jatropha curcas L under real field conditions, was able to accumulate and transfer mercury to its aerial parts, as well as tolerate high concentrations of copper, evidenced an improvement in soil physicochemical conditions mainly in the organic matter content.