Total and Leachable Heavy Metals in Muddy and Sandy Sediments of Egyptian Coast Along Mediterranean Sea

Abstract

The assessment of marine pollution due to metals was made for surficial sediments sampled from 20 sites along Mediterranean coast of Egypt. The samples were dried, acid digested and analyzed for leachable and total heavy metal contents (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) by flame atomic absorption spectrophotometer (air-acetylene) with deuterium background correction. Evaluation of the heavy metals pollution status was carried out using enrichment factors (EFs), the effect range-low (ERL) and the effect range-median (ERM). The study showed high concentrations of Cd, Co, Pb, Ni and moderate concentrations of Cr, Cu and Mn were contaminated in the sediments of studied sites. The results of Spearman correlation, factor and cluster analysis of the heavy metals analyzed in the collected sediment were discussed. The main source of contamination is the offshore oil field and industrial wastes, which arise due to the ineffective and inefficient operation equipments, illegal discharge and lack of supervision and prosecution of offenders.

Increased Bioavailability of Mercury in the Lagoons of Lomé, Togo: The Possible Role of Dredging

“…Greater content in clay, and higher concentrations in Al and Fe, could favor solid phase retention of other trace elements (El Nemr et al 2007;Preda and Cox 2002). This was not observed here as shown by the relatively low correlation coefficients found for these metals in the Western lagoon.…”

“…Negative correlation with MeHg was also observed for the Eastern lagoon or the southern parts of the lagoons, despite showing positive correlation with Mn, suggesting that other elements (whether metals or organic matter) could then participate to the decrease bioavailability of Hg. In addition, high correlation between TOC, and geological metals like Al, Fe, and Zn might be caused by an organic adsorption on clay, and aluminosilicate minerals (El Nemr et al 2007;Preda and Cox 2002). For example, the fact to have relatively less Al, Fe, Zn, and TOC in the Eastern lagoon could contribute to the greater bioavailability and methylation of Hg observed there.…”

Occurrence and distribution of selected heavy metals in the surface sediments of Thermaikos Gulf, N. Greece. Assessment using pollution indicators

“…Accumulation of heavy metals in sediments, even when present in low concentrations in the overlying water column, is dependant on various factors such as the nature of the sediment particles, the properties of the adsorbed compounds and the prevailing physicochemical conditions. Sediments show a great capacity to accumulate and integrate heavy metals and organic pollutants even from low concentrations in the overlying water column [1][2][3]. Although most pollutants adsorbed on the sediments are not bioavailable, certain mechanisms may induce the release of pollutants back to the water column.…”

Health Risk Assessment of Some Heavy Metals in Water and Sediment at Marsa-Matrouh, Mediterranean Sea, Egypt

“…One of the most crucial properties of heavy metals is that they are not biodegradable in the environment. In marine ecosystems, sediments show a great capacity to accumulate and integrate heavy metals and organic pollutants even from low concentrations in the overlying water column [3] [4] [5] [6] and so it acts as the main sink for metals [7] [8] and other pollutants [9]. Although most pollutants adsorbed on the sediments are not bioavailable, certain mechanisms may induce the release of pollutants back to the water column including sediment resuspension, desorption, redox reactions or (bio-)degradation of the sorptive substance [10] [11] [12] [14] [15] that can have toxic adverse effects on living organisms [16] [17] [18].…”