الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 116 |  |  |
| | | from | 116 | | |
Abstract
The accumulation of metals in fresh water has adverse effects on ecosystems and humans. Recently contamination of water, fish and sediment with metals in the Nile River at Egypt has a high concern. Metals concentration are a result of different types of waste water discharge from pointed and non-pointed sources of industrial, agricultural, and domestic waste water. The poor waste water management in the eastern side of Beni-Suef governorate threatens the environment and public health, where many sites in the eastern desert become dumps for sewage, industrial and agricultural waste water. Waste water dumps deteriorate the surface water in the Torrent drainage channel and Nile River. The effects of spatio-temporal variations on Copper (Cu), Lead (Pb), Zinc (Zn) and chromium (Cr) levels were monitored in water, fish and sediment, in addition to physico-chemical parameters such as pH, dissolved oxygen (DO), electric conductivity (EC), total dissolved solids (TDS), sulfate (SO4), nitrate (NO3), and nitrite (NO2) that were assessed in water to determine its quality. Health risk assessment was estimated for carcinogenic and non-carcinogenic adverse health effects for different exposure routes based on US Environmental Protection Agency (USEPA) methodologies, such as water or fish ingestion and dermal contact with water or sediment. Various methods were used to detect the environmental and ecological risks such as geo accumulation index (Igeo), potential ecological risk (RI) and sediment quality guidelines (SQGs).
The current data for water samples indicated that EC, TDS, SO4 and NO3 values in the five sampling sites were above the World Health Organization (WHO) limits during winter season, while during summer season only S2 and S3 exceeded the WHO guideline values. Pb values in the five sampling sites were above the WHO limits during both winter and summer seasons. Metals in water showed the following sequence Zn> Cu> Pb> Cr. The present data for fish muscle samples indicated that metals accumulated in fish muscles at the following order Zn> Cu> Cr> Pb. Zn and Pb that accumulated in fish muscles exceeded the permissible limits of WHO especially during summer season. Metal Pollution Index (MPI) for fish muscles during winter season was S5>S3>S2>S4>S1 and during summer season was S4> S3> S2> S5> S1. The results of sediment samples showed that metal concentrations were in the order: Zn> Cr> Cu> Pb.
For water consumption, Hazard quotients (HQs) of all parameters were less than 1 except for NO3 in S2 and S3 which showed HQ> 1 through oral exposure. Collectively, Hazard indices (HIs) for oral exposure values were higher than 1 in all the sampling sites except at S1 during winter and summer seasons. HQs and HIs were less than 1 via dermal exposure. There is expected carcinogenic adverse health effects on human populations especially farmers and fishermen through their exposure to the contaminated water, where CRs were more than unity 1.0E-6 except for Cr via dermal exposure. For fish consumption, HQs for individual metals were below 1, but collectively metals may induce adverse health effects on habitual consumers. Also the excessive and continuous consumption of fish from the current sampling sites may induce cancer for consumers. HQs, HIs and CR values indicated that human inhabitants in the nearby area from the current sampling sites may not expose to carcinogenic or non-carcinogenic adverse health effects through dermal contact of their lower legs with the contaminated sediments. Geo accumulation index (Igeo) classified the surface sediment samples in the current study as uncontaminated sediments. Potential ecological risk index (RI) showed that metals in the sediments may pose a low risk in the ecological system. The effect range median (ERMQ) and the probable effect level (PELQ) quotients clarified that metal contaminated sediments could be related with 12% and 10% probability of toxicity respectively, except for Cr concentrations where its PELQ values were related with 25.5% probability of toxicity.
So human population live in the nearby area may experience carcinogenic and non-carcinogenic adverse health effects during their life time through the exposure to the contaminated water or fish consumption, while their exposure to the contaminated sediments is not expected to induce any adverse health effects. The ecological and biological risks on the aquatic living organisms are low, so the contaminated sediments may not threat the ecosystem health yet.