The Environmental Impact Assessment (EIA) is the set of studies carried out by a multidisciplinary team, with detailed technical data, which evaluates the consequences of a given project for the environment. In the EIA, the impacts that a given project can cause in the environment, as well as the presentation of mitigating measures, are identified and evaluated technically and impartially. In this way, the EIA is an important instrument of Environmental Assessment (EA).
The aim of the assessment is to guarantee that decision makers take into consideration the environmental impacts when deciding whether to execute with a project.
The environmental impact assessment is defined by The International Association for Impact Assessment (IAIA) as 'the process of identifying, predicting, evaluating and mitigating the biophysical, social, and other relevant effects of development proposals prior to major decisions being taken and commitments made'.
In Brazil, commonly, the EIA (Estudo de Impacto Ambiental in Portuguese) is a robust document, made of many relevant socio-environmental information about the enterprise and the surrounding environment. Access to the EIA is restricted, with respect to industrial secrecy. In this sense, an Environmental Impact Report (Relatório de Impacto ao Meio Ambiente - RIMA in Portuguese) is also required and helps to give transparency to the EIA.
The RIMA reflects the main conclusions of the EIA and should be presented in an objective and adequate way to its understanding by different sectors of society. In this way, the information must be translated into accessible language, illustrated by maps, graphs, charts, and other visual communication techniques, in order to understand the negative and positive impacts of the enterprise, as well as the socio-environmental consequences of its implementation. In summary the RIMA is a conclusive report of the EIA, which translates technical terms into language accessible to the public for clarification.
Both EIA and RIMA are instruments of the Environmental Assessment (Avaliação de Impacto Ambiental – AIA in Portuguese) and were instituted by the Conselho Nacional de Meio Ambiente - CONAMA in January 23, 1986.