Abstract The recovery of degraded areas is imperative for the sustainability of mining activities. The main action implemented to improve the chemical, physical and biological conditions of soils, tailings and sterile deposits is the incorporation of organic material. Biosolids (hygienized sewage sludge) are among the organic materials that can be applied. However, considering the health risk they represent, not all areas are suitable for receiving this waste. The present research sought to map the environmental suitability of the Quadrilátero Ferrífero (QF) region to assess the applicability of biosolids. For this purpose, maps were elaborated using restrictive criteria established for the safe application of this residue to the soil by means of the Geographic Information System (GIS), using the ArcGIS software, version 10.2. The established criteria were pedology, topography, hydromorphism, presence of protected areas, soil texture, susceptibility to erosion, proximity to urban areas and their overlaps to obtain the final suitability areas. For the exclusion of areas that presented legal restrictions, the criteria of protected area, areas close to water bodies, urban areas, shallow soils and a slope greater than 45% were used, as established in literature, in CONAMA 498/2020 and in the Forest Law - Federal Law 12,652 of 2012. Of the areas analyzed, 58.5% were suitable for biosolid application, equivalent to 10,858.3 ha of the 18,587 ha studied, indicating the feasibility of biosolids application in part of the QF area to be recovered.

RESUMO Neste estudo, objetivou-se avaliar alterações químicas e sanitárias de solos e estéril de mina da região do Quadrilátero Ferrífero/MG, pela incorporação de lodo de esgoto sanitário e composto orgânico comercial, utilizando a adubação química convencional como tratamento controle. O estudo foi desenvolvido na área experimental da Mina de Águas Claras/MG, sendo os solos (Latossolo e Cambissolo) e estéril de mina analisados por um período de oito meses depois de efetuadas as adubações de, respectivamente, 49,9, 59,7 e 54,8 kg ha-1 de lodo de esgoto sanitário; 117,4, 140,1 e 128,8 kg ha-1 de composto orgânico comercial; e 150 kg ha-1 de fertilizante mineral em todos os materiais. No que se refere aos aspectos sanitários, o lodo de esgoto sanitário e o composto orgânico comercial foram classificados como “Classe A”, de acordo com a Resolução do Conselho Nacional do Meio Ambiente 375/2006. Após a aplicação dos adubos, avaliaram-se os teores de matéria orgânica, macro e micronutrientes, capacidade de troca catiônica, índice de saturação por bases, índice de saturação por alumínio, Al3+, H+Al, além dos teores de alguns metais pesados nos solos e estéril, além da quantificação de ovos viáveis de helmintos. Observou-se que a incorporação de lodo de esgoto sanitário e composto orgânico comercial foi capaz de aumentar os teores de matéria orgânica e fertilidade dos materiais e, embora a aplicação do lodo de esgoto sanitário também tenha proporcionado aumento nos teores de alguns metais pesados, não foi suficiente para proporcionar perda de sua qualidade ambiental, de acordo com a Conselho Nacional do Meio Ambiente 420/2009 (BRASIL, 2009). Não houve restrições sanitárias para o uso do lodo de esgoto sanitário em solos e estéril a serem recuperados em áreas de mineração do Quadrilátero Ferrífero/MG.

ABSTRACT The objective of this study was to evaluate chemical and sanitary changes in soils and sterile mine in the Quadrilátero Ferrífero region, Minas Gerais, by incorporating the sanitary sewage and commercial organic compost, using a conventional chemical fertilizer as treatment control. The study was carried out in the experimental area of the Mina de Águas Claras, Minas Gerais, the soils (Latosol and Cambisol) and mine sterile were analyzed for a period of 8 months after fertilization, respectively, 49,9; 59,7 and 54,8 t ha-1 SS; 117,4; 140,1 and 128,8 t ha-1 de commercial organic compost; and 150 kg ha-1 of mineral fertilizer in all materials. Regarding sanitary aspects, the SS and the commercial organic compost were classified as “Class A”, according to Conselho Nacional do Meio Ambiente 375/2006. After the application of fertilizers, the contents of organic matter, macro- and micronutrients, cation exchange capacity, base saturation index, aluminum saturation index, Al3+, H+Al, levels of metals were evaluated in the soil and sterile, in addition to quantifying viable helminth eggs. It was observed that the incorporation of sanitary sewage and commercial organic compost was able to increase the levels of organic matter and fertility of materials and, although an application of sanitary sewage also provided an increase in the contents of some heavy metals, it was not enough to lose its environmental quality, according with Conselho Nacional do Meio Ambiente 420/2009 (BRASIL, 2009). There were no sanitary restrictions on the use of sanitary sewage and commercial organic compost in soils and sterile to be recovered in the Quadrilátero Ferrífero mining areas.