Nile Water Science & Engineering Journal, Vol. 7, Issue 1, 2014 68 Assessment of Contamination in Sediments of Lake Nubia in Sudan Asmaa A. Agrama 1 1 Environment & Climate changes Research Institute, National Water Research Center, El-Qanater El- Khairiya, Egypt. Postal Code:13621/5 Abstract The heavy metals deposited in the sediment are probably due to anthropogenic and natural sources. It can be said that the environmental or human impact involving these metals is occurring in the aquatic environment and can cause hazard to sediments dwelling organisms as well as the populace in the area through food chain. On the other hand climate changes are projected to reduce raw water quality as increased sediment, nutrient, and pollutant loadings from heavy rainfall. Greater runoff results in greater loads of salts, faecal coliforms, pathogens and heavy metals. The environmental pollution of heavy metals in the sediment of the north part of Lake Nubia, Sudan was assessed. Heavy metals data from 12 locations were obtained from literature review as sediment samples were collected and analyzed in 2009. The degree of contamination in the sediments of Lake Nubia, for the metals Cu, Pb, Zn, Fe, and Mn has been evaluated using Geo-accumulation index (Igeo) and Pollution Load index (PLI). Seven and two contamination classes and terminologies suggested for Igeo and PLI respectively were used in this paper. Igeo results for sediments in the studied area ranged from (-34.51) to (-2.4). PLI for all locations are less than 1. Results of Igeo and PLI for sediment in different studied locations indicated that the sediment quality is unpolluted for whole locations in the studying area. The results recommended that these cleaned sediments may be very useful for agriculture using in residential regions around the Lake Nasser/Nubia. On the other hand the characteristics for all Lake Nasser/Nubia sediment are necessary to evaluate its potential using for agricultural. Keywords: Heavy Metals, Sediment , Igeo, PLI, Lake Nubia. 1. INTRODUCTION The aquatic environment quality is projected to reduce due to climate change. The sources of the risks on water quality are increased temperature, nutrient and pollutant loadings due to heavy rainfall, and increases in sediment. Greater runoff results in greater loads of salts, faecal coliforms, pathogens and heavy metals (Pednekaret al, 2005). Increased in temperature appears that adsorptive capacity for heavy metals in sediment increases when the temperature rises (WMO, 2003). Water, sediment and biota can use as an indicator to determine the level of heavy metal pollution in aquatic environment. Sediments are important sinks for various pollutions like organic and inorganic (heavy metal) and also play a significant role in the assessment of ecological risk (Balls et al, 1997). Heavy metals are of high ecological significance since they are not removed from water through self purification or biodegradable, they can either be adsorbed on sediment particles or accumulated in aquatic organisms (Loska and Wiechula, 2003). The concentrations of heavy metals in sediments are varied according to the rate of particle sedimentation, the rate of heavy metals deposition, the particle size and the presence or absence of organic matter in the sediments (Salomanet al, 1987). Gesseyet al, 1984 stated that heavy metals react readily with suspended particulate matters and through sedimentation processes, accumulate in bottom deposits. Sediment not only acts as the carrier of contaminants, but also as the potential secondary sources of contaminants in the aquatic system (Calmanoet al, 1990). Elewaet al, (1990) reported that the bottom sediment acts as accumulator for heavy metals and the rate of accumulation depends mainly on different environmental parameters. This means that any change in environmental conditions in the system may render the remobilization of metals from the sediments (Calmanoet al, 1993). So the accumulation of metal contaminants in sediments can pose serious environmental problems to the surrounding areas. Trace metal contamination in sediment could affect the water quality and the bio-assimilation and bio-accumulation of metals in aquatic organisms, resulting in potential long-term implications on human health and ecosystem. Essential metals such as Cu, Zn and Fe have normal physiological regulatory functions (Hogstrand and Haux,2001), but may bio-accumulate and reach toxic levels. Non-essential metals are usually potent toxins and their bio-accumulation in