Resumo

GONZALEZ FLORES, Eduardo; TORNERO CAMPANTE, Mario Alberto; ANGELES CRUZ, Yolanda  e  BONILLA Y FERNANDEZ, Noemí. Total concentration and speciation of heavy metals from urban biosolids. Rev. Int. Contam. Ambient [online]. 2009, vol.25, n.1, pp.15-22. ISSN 0188-4999.

The analysis of heavy metals is a very important task to asses the potential environmental and health risk associated with biosolids deposition in agricultural soil. However, it is widely accepted that determination of total concentration of heavy metals does not give an accurate estimation of the potential environmental impact. So, it is necessary to apply speciation studies to obtain suitable information about their bioavailability. This study was carried out on sewage sludge samples collected in a municipal waste-water treatment plant, located in Puebla City (México). They are used for amendment agricultural soil. The speciation of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) was made using a sequential extraction procedure. The aim was to determine their concentration in bioavailability fractions. It was got the total concentration of heavy metals using acid digestion in a closed system and was determined with atomic absorption spectrometry. The total concentrations of heavy metals were lower than that established by Mexican legislation. The heavy metals are mainly associated with the mineral fraction and organic matter and consequently they show low bioavailability.

Palavras-chave : total concentration; speciation; heavy metals; biosolids; sequential extraction.