Analysis and assessment of heavy metals in urban surface soils of Teresina, Piauí State, Brazil: a study based on multivariate analysis

Abstract

The concentration of Cu, Pb, Zn, Cr, Ni and Mn in the surface soil samples from Teresina city were measured by flame atomic absorption spectrometry (FAAS). A total of 28 composite soil samples were collected at depths 0-10 cm, including residential districts, urban parks, green areas, vegetable-garden, heavy- and low-traffic density areas. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to analyze the data and identify possible sources of these heavy metals. The results of the multivariate analysis showed that Cu, Pb, Zn and Cr were associated mainly to anthropogenic activities, such as, fertilizer and vehicle emission. While Ni and Mn were controlled by original materials and therefore interpreted as natural sources.The concentration of Cu, Pb, Zn, Cr, Ni and Mn in the surface soil samples from Teresina city were measured by flame atomic absorption spectrometry (FAAS). A total of 28 composite soil samples were collected at depths 0-10 cm, including residential districts, urban parks, green areas, vegetable-garden, heavy- and low-traffic density areas. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to analyze the data and identify possible sources of these heavy metals. The results of the multivariate analysis showed that Cu, Pb, Zn and Cr were associated mainly to anthropogenic activities, such as, fertilizer and vehicle emission. While Ni and Mn were controlled by original materials and therefore interpreted as natural sources. Análise e avaliação dos metais pesados em solos superficiais urbanos de Teresina,Estado do Piauí, Brasil: um estudo baseado em análise multivariadaResumoA concentração de Cu, Pb, Zn, Cr, Ni and Mn nas amostras de solo superficial da cidade deTeresina foram medidas por espectroscopia de absorção atômica em chama (FAAS). Um total de28 amostras compostas de solo foram coletadas numa profundidade de 0–10 cm, incluindo distritosresidenciais, parques urbanos, áreas verdes, hortas, áreas de densidade de tráfico baixo e alto.Análise por componentes principais (PCA) e análise por agrupamento hierárquico (HCA) foramusadas para analisar os dados e identificar as possíveis fontes desses metais pesados. Os resultadosda análise multivariada mostraram que Cu, Pb, Zn e Cr foram associados, principalmente, àsatividades antropogênicas, tais como, fertilizantes e emissões veiculares. Enquanto Ni e Mn foramcontrolados por material parente, portanto interpretado como fonte natural