Estudo da origem, disponibilidade e mobilidade de ferro nos sedimentos superficiais do fundo do estuário dos Bons Sinais, Quelimane-Zambézia

Abstract

This work aimed to analyze the origin, availability and mobility of iron in the sediments of the Bons Sinais Estuary. For this purpose, samples of bottom surface sediments of five (5) transects located along the estuary were collected and analyzed. The analyzes involved the determinations of the physical-chemical parameters (texture, pH and organic matter), total iron (Fe2O3) and available iron (Fe) in the samples. The determination of total iron (Fe2O3) and available iron (Fe) were made by the molecular absorption spectrophotometry technique from the Sulfuric Attack digestion and Mehlich-1 extraction methods, respectively. Control of the accuracy of the methods was done using reference material and accuracy by means of the repeatability of the measurements. Results obtained from the physicochemical parameters evidenced the sediments of the environment as being predominantly clayey, alkaline and mineral. The accuracy and precision obtained from Fe2O3 and Fe measurements showed satisfactory results. The results obtained of iron had a significant spatial variation, with concentration of 2.55 to 9.9 dag.Kg-1 for Fe2O3, typical of the study environment and 2307 to 5064 mg.Kg-1 for Fe, the latter below toxic effects for most of the living organisms exposed in the sediments and having been found low mobility of the same in most of the transects of the studied area