Changes in soil properties during iron mining and in rehabilitating minelands in the Eastern Amazon

• Published in: Environmental monitoring and assessment 2022-04, Vol.194 (4), p.256-256, Article 256
• Main Authors: Ramos, Silvio J., Gastauer, Markus, Martins, Gabriel C., Guedes, Rafael S., Caldeira, Cecilio F., Souza-Filho, Pedro W. M., Siqueira, José O.
• Format: Article
• Language: English
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; Cast iron; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring; Environmental science; Fertility; Forests; Iron; Metal industry wastes; Mineral nutrients; Mining; Monitoring/Environmental Analysis; Nutrients; Organic matter; Organic soils; Outcrops; Physical properties; Piles; Recovery; Rehabilitation; Revegetation; Soil - chemistry; Soil fertility; Soil improvement; Soil organic matter; Soil physical properties; Soil Pollutants; Soil properties; Soil quality; Substrates; Vegetation
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-022-09892-y

Open-cast iron mining causes drastic disturbances in soil properties. Recovery of soil chemical and physical properties is essential for successful revegetation and landscape rehabilitation. To identify changes in soil properties during the mining and revegetation process, soil samples were collected from undisturbed sites represented by forest and ferriferous savannas stocking above iron outcrops, called “ cangas ,” in open-pit benches, and in rehabilitation chronosequences of iron waste piles in the Carajás Mineral Province (CMP), Eastern Amazon, Brazil. The samples were analyzed for chemical and physical properties. Our results showed that iron mining operations resulted in significant alteration of the chemical soil properties when forest and canga vegetation are suppressed to form open-pit benches or waste piles in the CMP. Mining substrates showed lower contents of soil organic matter (SOM) and nutrients than undisturbed areas of forests and cangas . In order to achieve the success of revegetation, nutrients have been added prior to plant establishment. We have demonstrated how soil fertility changes along with mineland rehabilitation, and the variation among chronosequence was attributable mainly due to contents of SOM, K, and B in the soil. The slight improvement of SOM found in rehabilitated waste piles reinforces the notion that recovery of soil quality can be a slow process in iron minelands in the CMP.