Classificação de Antropossolos em áreas de antigos depósitos de resíduos sólidos urbanos em Presidente Prudente - SP: contribuição metodológica
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Data
2017-11-14
Autores
Antonio, Janaina Natali
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Universidade Estadual Paulista (Unesp)
Resumo
A expansão de áreas urbanas e os diferentes tipos de uso da terra, nestas áreas, causam modificações nas características naturais dos solos, pois no ambiente urbano há a ação de diversos processos mecânicos, como a retirada, transporte e deposição de materiais de diversas origens e composições. As alterações no solo são significativas, de forma que muitos países inseriram novas categorias de solos aos seus sistemas de classificação. No Brasil, os solos resultantes de ações antrópicas, foram conceituados como Antropossolos, caracterizados pelas alterações na paisagem e na composição física e química, incluindo a presença de artefatos e materiais contaminantes. Para realizar a caracterização e o mapeamento dos Antropossolos, inicialmente foi realizado o levantamento das características dos solos naturais, sua relação com os atributos do relevo no município de Presidente Prudente – SP, e o mapeamento preditivo de solos, com uso de redes neurais artificiais. A compreensão da relação existente entre os solos e os atributos do relevo derivados de um modelo digital de elevação forneceu informações para relacionar os principais padrões de ocorrência de tipos de solos aos atributos de elevação, declividade, curvatura do relevo, geoformas e aspecto. Entre as variáveis utilizadas para o mapeamento preditivo dos solos, as que tiveram destaque foram declividade e geoformas, apresentando similaridade de padrão de ocorrência. As áreas de ocorrência dos Neossolos estão, principalmente, relacionadas às áreas de declividades de 20% ou acima, os Latossolos têm padrão de ocorrência nas áreas com declividades inferiores a 8%, os Argissolos variam em declividades médias acima de 3% e abaixo de 20% e os solos hidromórficos (Gleissolos e Planossolos) estão localizados nos fundos de vale com declividades abaixo dos 3%. As redes neurais artificiais se mostraram uma técnica eficiente para o delineamento das unidades de solos e permitiram a identificação de componentes da paisagem por meio do estabelecimento de padrões gerados a partir das coletas de amostras. Com base nos atributos do relevo e do mapeamento preditivo dos solos foi realizada a caracterização das áreas de antigos depósitos de resíduos sólidos urbanos na área urbana de Presidente Prudente – SP, as quais estão predominantemente localizadas nos compartimentos de fundos de vale, em curvaturas côncavas, declividades de relevo ondulado e forte ondulado e em solos Argilosos e hidromóficos (Gleissolos e Planossolos). Os Antropossolos em antigas áreas de disposição de RSU são classificados no segundo nível como Líxicos, devido à presença de materiais orgânicos e artefatos de origem e composições diversas, e podem conter substâncias contaminantes. Para a classificação no terceiro e quarto níveis foi delimitada uma área de influência a partir de uma das antigas áreas de disposição de RSU, localizada no Parque Furquim. Foram realizadas análises granulométricas e de presença de metais pesados nos solos. Os elementos analisados foram Arsênio (As), Cádmio (Cd), Chumbo (Pb) e Crômio (Cr). Os resultados foram comparados com os Valores de Referência de Qualidade utilizados no estado de São Paulo, e indicaram a presença de Chumbo (Pb) e Crômio (Cr) acima dos Valores de Referência de Qualidade em alguns pontos, localizados à montante da área delimitada, em fundos de vale próximos ao curso d’água. A área foi classificada pela ocorrência de Antropossolos Líxicos Áquicos e Órticos com presença de elementos tóxicos e de Antropossolos potenciais. Por se tratar de um conceito recente, os estudos para o conhecimento das características dos Antropossolos, são fundamentais para a compreensão da sua dinâmica e para propor medidas de recuperação e de planejamento para o uso adequado.
The expansion of urban areas and different types of land use in these areas cause modifications in the natural characteristics of the soils, since in the urban environment there are several mechanical processes, such as the removal, transportation, and deposition of materials of various origins and compositions. The alterations in the soil are significant, with many countries inserting new soil categories into their classification systems. In Brazil, soils resulting from anthropic actions are considered as Anthroposols, characterized by changes in the landscape and physical and chemical composition, including the presence of artifacts and contaminating materials. In order to carry out the characterization and mapping of the Anthroposols, initially a survey of the characteristics of the natural soils was carried out, including their relation with the attributes of the relief in the municipality of Presidente Prudente - SP, and the predictive mapping of soils, using artificial neural networks. Understanding of the relationship between the soils and relief attributes derived from a digital elevation model provided information to relate the main patterns of occurrence of soil types to the attributes of elevation, slope, relief curvature, geoforms, and aspect. Among the variables used for the predictive mapping of soils, those that stood out were slope and geoforms, presenting similarities in patterns of occurrence. The areas of occurrence of the Neosols are mainly related to the slope areas of 20% or above, the Oxisols present a pattern of occurrence in areas with slopes lower than 8%, the Argisols vary in average slopes above 3% and below 20%, and the hydromorphic soils (Gleysols and Planosols) are located in valley bottoms with gradients below 3%. Artificial neural networks proved to be an efficient technique for the delineation of soil units and allowed identification of landscape components by establishing patterns generated from sample collections. Based on the attributes of soil relief and predictive mapping, characterization of areas of former urban solid waste deposits in the urban area of Presidente Prudente – SP was carried out, predominantly located in valley bottom compartments, in concave curves, slopes of undulating relief and strong undulation and in clayey and hydromorphic soils (Gleysols and Planosols). Anthroposols in former USW disposal areas are classified in the second level as Líxicos, due to the presence of organic materials and artifacts of various origins and compositions, which may contain contaminating substances. For classification in the third and fourth levels, an area of impact from one of the former USW disposal areas was delimited, located in Parque Furquim. Granulometric analyzes and evaluation of the presence of heavy metals in the soils were carried out. The analyzed elements were Arsenic (As), Cadmium (Cd), Lead (Pb), and Chromium (Cr). The results were compared with the Quality Reference Values used in the state of São Paulo and indicated the presence of Lead (Pb) and Chromium (Cr) above the Quality Reference Values at some points, located upstream of the delimited area, in valley bottoms near the watercourse. The area was classified by the occurrence of Líxicos Áquicos and Órticos Anthroposols with the presence of toxic elements and potential Anthroposols. As it is a recent concept, studies aiming to increase knowledge on the characteristics of Anthroposols are fundamental to the understanding of their dynamics and to propose measures of recovery and planning for appropriate use.
The expansion of urban areas and different types of land use in these areas cause modifications in the natural characteristics of the soils, since in the urban environment there are several mechanical processes, such as the removal, transportation, and deposition of materials of various origins and compositions. The alterations in the soil are significant, with many countries inserting new soil categories into their classification systems. In Brazil, soils resulting from anthropic actions are considered as Anthroposols, characterized by changes in the landscape and physical and chemical composition, including the presence of artifacts and contaminating materials. In order to carry out the characterization and mapping of the Anthroposols, initially a survey of the characteristics of the natural soils was carried out, including their relation with the attributes of the relief in the municipality of Presidente Prudente - SP, and the predictive mapping of soils, using artificial neural networks. Understanding of the relationship between the soils and relief attributes derived from a digital elevation model provided information to relate the main patterns of occurrence of soil types to the attributes of elevation, slope, relief curvature, geoforms, and aspect. Among the variables used for the predictive mapping of soils, those that stood out were slope and geoforms, presenting similarities in patterns of occurrence. The areas of occurrence of the Neosols are mainly related to the slope areas of 20% or above, the Oxisols present a pattern of occurrence in areas with slopes lower than 8%, the Argisols vary in average slopes above 3% and below 20%, and the hydromorphic soils (Gleysols and Planosols) are located in valley bottoms with gradients below 3%. Artificial neural networks proved to be an efficient technique for the delineation of soil units and allowed identification of landscape components by establishing patterns generated from sample collections. Based on the attributes of soil relief and predictive mapping, characterization of areas of former urban solid waste deposits in the urban area of Presidente Prudente – SP was carried out, predominantly located in valley bottom compartments, in concave curves, slopes of undulating relief and strong undulation and in clayey and hydromorphic soils (Gleysols and Planosols). Anthroposols in former USW disposal areas are classified in the second level as Líxicos, due to the presence of organic materials and artifacts of various origins and compositions, which may contain contaminating substances. For classification in the third and fourth levels, an area of impact from one of the former USW disposal areas was delimited, located in Parque Furquim. Granulometric analyzes and evaluation of the presence of heavy metals in the soils were carried out. The analyzed elements were Arsenic (As), Cadmium (Cd), Lead (Pb), and Chromium (Cr). The results were compared with the Quality Reference Values used in the state of São Paulo and indicated the presence of Lead (Pb) and Chromium (Cr) above the Quality Reference Values at some points, located upstream of the delimited area, in valley bottoms near the watercourse. The area was classified by the occurrence of Líxicos Áquicos and Órticos Anthroposols with the presence of toxic elements and potential Anthroposols. As it is a recent concept, studies aiming to increase knowledge on the characteristics of Anthroposols are fundamental to the understanding of their dynamics and to propose measures of recovery and planning for appropriate use.
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Palavras-chave
Antropossolos, Solos, Redes neurais artificiais, Resíduos sólidos urbanos, Modelo digital de elevação, Antigas áreas de disposição, Anthroposols, Soils, Relief, Digital elevation model, Former disposal areas, Urban solid waste