Distribuição de elementos químicos tóxicos As, Cd, Ni, Pb e Sb em superfícies de solos de parques e praças da Região Metropolitana do Recife (RMR) Pernambuco

Abstract

With the increase in agricultural areas, urbanization, industry and consequently the increase in pollution and loss of environmental quality, soil monitoring for the presence of toxic chemical elements and their distribution on the surface in urban green areas are fundamental for the conservation and maintenance of ecosystem services . Considering the relevance of urban parks and squares for the well-being of the population, this study aimed to evaluate soils, based on the determination of toxic chemical elements As, Cd, Ni, Pb and Sb in soils of urban green areas in the Metropolitan Region do Recife - RMR, Pernambuco, Brazil. The soil sampling units were georeferenced and composite soil samples were collected under the projection of the tree canopy at a depth of 0-15 cm, followed by drying and maceration. For chemical determination by Graphite Furnace Atomic Absorption Spectrometry - GFAAS and Inductively Coupled Plasma Mass Spectrometry - ICP-MS, chemical treatment was used to solubilize the samples, analytical blanks and reference materials to control the quality of the analytical procedures. As, Cd, Ni, Pb and Sb presented levels in the soils below the limit foreseen in CONAMA Resolution number 460. To evaluate the level of soil pollution, the Improved Nemerow Index was estimated, which indicated a high presence of Ni with IMN = 5 .06 (class 5), for Praça de Paulista being classified as very contaminated and IMN = 4.04 (class 4) for the same element in Parque 13 de Maio was classified as highly contaminated. Sb antimony with IMN = 4.42 (class 4) is highly contaminated; for the other study sites they were classified as moderately contaminated to heavily contaminated. With the maps generated using the Kriging technique, different dynamics can be observed in the distribution of the elements under study on the soil, highlighting the need for environmental monitoring of soils in parks and squares in the RMR.