Behavior of metals (Pb, Zn, Fe, Al and Ni) during coal mine drainages treatment in constructed wetlands

• Julio César Marín Universidad del Zulia-Venezuela
• Adriana López Universidad del Zulia-Venezuela
• Elisabeth Behling Universidad del Zulia-Venezuela
• Gilberto Colina Universidad del Zulia-Venezuela
• Nola Fernández Universidad del Zulia-Venezuela

Palabras clave: coal, constructed wetlands, mine drainages, metals, Typha dominguensis

Resumen

In the present investigation the behavior of heavy metals Pb, Zn, Fe, Al and Ni, during the treatment of coal mine drainages in constructed wetlands dominated by Typha dominguensis was studied. The tests were done in tanks provided with two different support materials (sediment of storage drainages pit and grave), implementing the hydraulic retention times (HRT) of 24, 72, 120, 168 and 216 h. The metal determinations by atomic absorption spectrometry showed good precision (standard relative deviation = 2.41%) and accuracy (recovery percentage between 96.08 and 103.66%). The metal concentration (mg/L) was 0.48-1.36 Pb, 0.67-28.28 Zn, 0.13-3.38 Fe, 0.62-146.80 Al and 0.08-4.39 Ni. In general it was observed a noticeable tendency towards the reduction of metal contents as the HRT was increased, especially in the wetlands with pit sediments (initially release). The Pb showed minor trend to removal. The release from pit sediments, plant secretions and material atmospheric deposition, could be the related mechanisms to metal mobility. The necessity arises lo evaluate the wetland systems like possible sink or metal sources.