Contaminação de solos por cobre no Brasil: revisão sobre fontes, riscos ecológicos e mitigação

Abstract

Copper (Cu) is an element found naturally in soils, and its availability and presence are related to the degree of weathering of the soil and its parent material. However, excess Cu can cause contamination, impairing soil quality and the development of living organisms. In this context, this work aims to evaluate soil contamination by copper in Brazil through a bibliometric review related to the main sources and a systematic review addressing the levels, sources of contamination, resulting ecological risks and mitigation strategies. Forty-six publications from the scientific database Web of Science were selected through the systematic review, and information regarding the source and degree of contamination by Cu was collected. From the collected data it was possible to determine the geoaccumulation index (Igeo) and regression analysis between Cu contents and time of use, soil depth and organic carbon content. As a result of the bibliometric review, the theme “Science of the environment” was related to the main activities related to contamination by Cu in soils. Scientific production in Brazil was mainly concentrated at the Federal University of Santa Maria (UFSM), with 44 articles published, followed by the Federal University of Rio Grande do Sul (UFRGS), with 27. Cu contamination in soils derived from mining activities and vine cultivation obtained the highest averages of annual scientific production, with 2.8 and 2.1 articles published between 2003 to 2021 and 2007 to 2023, respectively. Regarding the systematic review, the results showed that the main studies on soil contamination by Cu are related to areas of grapevine cultivation with the application of cupric fungicide and arable areas with the application of swine manure, in Rio Grande do Sul and Santa Catarina. The highest average values of total Cu and Igeo content in the soil come from Cu mining tailings. The Igeo of soils with rejects of antifouling paint particles stands out due to its high contamination potential. The main consequence of Cu contamination is the negative effect on edaphic and aquatic organisms. According to data from the literature, the use of plant species such as Bidens pilosa, Mucuna cinereum, Mucuna aterrina, Canavalia ensiformis, and Avena sativa for the remediation of soils contaminated with Cu in Brazil. These plants may be associated or not with conditioners and fertilizers, with emphasis on the inoculation of fungi arbuscular mycorrhizae, capable of promoting Cu accumulation in the root system and aerial part.