国际废物资源杂志

抽象的

Impact of Heavy Metal Pollution on Procambarus clarkii (Crustacea: Decapoda), from Egypt

El Assal FM and Abdel-Meguid ZA

The present study was conducted to assess the accumulation of some metals (Fe, Cd, Cu, Pb, Mn, Mg, Ca and Zn) in the River Nile water and sediment, at four sites (Gezyrat Al- Warrak (site I), Manial Sheeha (site II), Al- Hawamdia (site III) and Helwan (site IV), at Great Cairo, as well as in the exoskeleton, hepatopancreas , muscles and gills of the crayfish Procambarus clarkii, collected from the same sites). The results obtained show that the different concentrations of the metals in the Nile water were in the descending order Mg>Zn>Fe>Cu>Mn>Pb>Cd, at all studied sites. Fe and Zn concentrations were higher than the permissible limits, while the remaining metals were within the allowable levels. Whereas, the concentrations of metals in the sediment showed different patterns, according to their abundance in water. The abundance of these metals in the sediment was in the order Fe>Mg>Ca>Zn>Mn>Cu>Pb>Cd, at sites I and II, Fe>Mg>Ca>Zn>Mn>Cu>Cd>Pb, at site III and Mg>Fe>Ca>Zn>Mn>Cu>Cd>Pb, at site IV. Metal concentrations in the sediment were higher many folds than their values in the overlaying water. P. clarkii accumulated heavy metals in its tissues regardless their abundance in the water and/or sediment. The concentrations of the selected metals in the crayfish muscles were lower than the international permissible levels. Relative to the allowable limits for metals in foods, there was no sufficient accumulation of any of the detected metals in the muscles of P. clarkii to indicate that no significant health hazard would result from the consumption of the muscle parts of the animal. This study suggests, also, that P. clarkii may be used as bioindicator for heavy metals pollution in the freshwater systems, as well accumulation of these pollutants can cause depuration of the accumulated metals by decreasing their amounts in water.