Quantification and statistical evaluation of metals and metalloids in water samples from Barra Longa after the rupture of the Fundao dam (Mariana)

ln November 2015, the disruption of an iron ore tailings dam located in the Doce river basin caused the largest environmental disaster ever occurred in Brazil and one of the largest in the world, releasing tons of mud that until today cause changes in the composition of the water. The objective of this work was to determine the total concentrations of metais and metalloids in the waters of Barra Longa, a district close to where the disaster occurred and to discuss the data using statistical methods. A total of 15 water samples were collected and the total concentrations of Ag, AI , As, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Sb, Se, Ta, U and V were determined in well waters and Fe, AI and Cu dissolved in pond and river waters by inductively coupled plasma mass spectrometry (ICP-MS). Four well water samples, which are consumed without any treatment, showed Fe concentrations well above the Maximum Permissible Values (MPV) by Portaria nº2921 do Ministério da Saúde and 1 sample presented Ni concentration 3 times above. Statistical analysis using HCA showed two groups, one of well water samples (group A) similar dueto the higher concentrations of Cr (0.598 to 3.224 μg.L-1) and other group (group B) with the other samples. The samples that underwent treatment were grouped due to the lower contents of Fe, showing the importance of the treatment in the removal of the metais.