Document Type : Original Article
Authors
1
Hydro-geochemistry, Desert Research Center, Cairo, Egypt
2
Soil Chemistry and Physics Department,Desert Research Center, Cairo, Egypt
3
Soil Fertility and Microbiology Department, Desert Research Center, Cairo, Egypt,
4
Environmental Pollution Unit, Plant Ecology and Range Management Department, Desert Research Centre, Cairo, Egypt
Abstract
Assessment of the environmental impact of the polluted water was studied along Bahr El-Bakr drain. Different samples of water, soil and the edible parts of vegetables, cereals and clover were collected from the study area. Chemical and/or microbiological analyses of these samples were achieved to examine water, soil and plant contamination. Chemical analysis of the collected water samples, that represented all irrigation water resources, showed that they range from fresh to brackish. For soluble heavy metals, there is no any inorganic pollutant in the collected water samples except one sample with high aluminum and iron concentrations,while using digestion method, high concentrations of most metals for all collected samples were recorded. On the other hand, high concentrations of organic pollutants included both TOC and COD were detected in most water samples.
Microbiological investigation of the water samples revealed their highly contamination with fecal coliforms and pathogenic bacteria. All soil samples of the study area showed remarkable pollution with higher microbial contamination compared to that of irrigation water of the same place.The summary statistics results indicated that the most important heavy metals with regards to potential hazards in studied soils are Pb and Cd. Average contamination factor values for heavy metals have the order Cd > Co > Ni > Cr > Cu > Pb > Zn > Fe, suggesting that soil samples were extremely enriched with Cd, while Pb exhibit significant enrichment. Geoaccumulation index showed that the soils of Bahr El-Bakr were uncontaminated with Fe, Zn, Cu, Ni, Co and Cr and moderately contaminated with Pb but Cd followed strongly/ extremely contaminated index.
It was also observed an elevation in nitrate contents in the edible parts of the collected leafy vegetables. Heavy metal concentrations in leaves, cereal, fruits tubers of edible parts of plants and shoots of clover plants decreased in the order; Fe > Al > Zn > Cu > Mn >B >Ni >Cr > Pb >Ba >V >Mo >Co >Cd, with increase of toxic metals such as Al, Cr, Pb, Ni and Cd concentrations that were higher than the permissible limits.These results indicated that long term irrigation with waste water from Bahr El-Bakr drain had a negative impact on both chemical and microbiological quality of soil and plants in this region.
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