Implementação e aplicação de metodologia para dosagem de metais e não metais em águas de drenagem de solo adubados com fosfogesso

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

13/04/2010

RESUMO

Phosphogysum is a waste generated in phosphoric acid production by the wet process. The immense amount of phosphogysum yearly produced (around 150 million tons) is receiving attention from environmental protection agencies all over the word, given its potential of contamination. In Brazil, this material has been used for many decades, especially for agricultural application on cropland. Although the phosphogysum is mainly composed of dehydrated calcium sulfate, it can have high levels of impurities, such as metals (Cd, Cr, Cu, Pb), non-metals (As and Se) and radioactive elements from natural series of 232Th and 238U. Therefore, its continual application as an agricultural agent can result not just in soil contamination, but also contamination of the surface and groundwater due to the runoff and infiltration process. The concern associated with the contamination of aquatic environments increases; when water is used for human consumption, requiring progressive adoption of more restrictive limits. However, some of the conventional analytical techniques used to determine the maximum limit of contaminants in water have detection limits above the maximum limits established by the environmental legislation. This work was aimed to evaluate the mobility of metals and non-metals in soils and, consequently, the contamination of drainage water through greenhouse-scale leaching and transport of toxic elements from soils fertilized with phosphogysum. Hence, methods were studied and implemented for determination of metals (Cd, Cr, Cu and Pb) using Furnace Graphite Atomic Absorption Spectrometry (GF AAS), as well as for non-metals (As and Se) using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Effects of different chemical modifiers on the determination of Cd, Cr, Cu and Pb concentration by GF AAS were also investigated. In general, it was observed that the metal and non-metal concentration were below than the actual detection limit of the equipment for all conditions of interest, indicating the low mobility of the analyzed elements in the soil column.

ASSUNTO(S)

rocha fosfática contaminaçao metais fertilizantes poluição da água impacto ambiental quimica nuclear e radioquimica phosphate rocks gypsum environmental impacts metals fertilizers water pollution

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