Studies on some heavy metals content in polluted soils and their accumulation in plants [electronic resource].

Includes references.

The present study was conducted to investigate the accumulation of some heavy metals (Cd, Cu. Pb and In) in soils and plants with different sources of pollution. The soil samples were collected from 3 sites from each of EI-Gabal EL¬ Asfar Abou-Rawash and Helwan areas which received sewage sludge and sewage effluent for a long time. Also, one soil sample from Helwan was collected to represent the contamination by industrial waste. The plant samples were taken from the same location of soil samples. Soil pH and total carbonate content (TCC) are slightly decreased as the irrigation period increased. However organic matter increased. Total, bioavailable contents of Cd. Cu. Pb, and in of soils increased as the irrigation period increased. Total contents exceeded, in many cases, and or reached, in some ones, the maximum permitted loadings. OTPA-extractable Cd, Cu, Pb and in increased continuously in the studied areas which received sewage sludge, sewage effluent and industrial materials for a long time. Bioavailable portions were found to represent a great deal of the total contents. The low percentage of total extracted by OTPA is d.ue to its precipitation as CaC03. These results give an evidence of high availability of sewage effluent burden metals to plants. There are negative correlation confections between OTPA extractable -Cd and each of pH and CaC03; and a positive correlation confections with total organic matter and clay contents. The concentrations of Cd, Cu, Pb and In in different plant organs increased with increasing the frrigation time period of sewage effluent and both sewage sludge and industfial material applications to soils. The absolute values of these metals in plant organs are different from metal to another, depending on the sewage sludge content and the availability of these metals in the soil which are controlled by different soil parameters (CaC03, pH, clay and organic matter). The values of these metals followed the order Cd < Pb < Cu < In. The obtained results indicate that the heavy metals accumulation in leaves or straw higher than edible parts (grains or seeds) of plants. This is due to the low translocations of these metals in plants.

Summary in Arabic.

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