Wyniki wyszukiwania - BazTech

1

Comprehensive assessment of water and sediment quality in Lake Nasser, Egypt, using various potential risk indices

Abdel-Satar Amaal M., Salem Salem G., El-Sayed Seliem M., Goher Mohamed E., Abdelaziz Ghada S., Al-Afify Afify D.G.

Oceanological and Hydrobiological Studies

|

2024

|

Vol. 53, No. 1

40--60

EN

Lake Nasser is a freshwater lake that supplies over 95% of Egypt’s freshwater budget. Therefore, the quality of water in the lake is critical for its conservation. In addition to assessing the metal pollution load, the quality of water and sediment in the lake was assessed by collecting water and sediment samples for metal content analysis. Lake Nasser is a warm monomictic water body with a single circulation cycle in the cold months. Dissolved oxygen content in bottom water samples often dropped significantly to levels below international guidelines, reflecting reduced rates of photosynthetic activity. Although 50% of the lake’s water samples contained Pb concentrations slightly above the World Health Organization’s (WHO) limit for drinking water, the metal pollution index did not exceed the critical level and was classified as low metal water pollution. Based on the geoaccumulation index (I-geo), the enrichment factor (EF) and the pollution load index, the sediments of Lake Nasser are practically uncontaminated with metals. Ni has the highest EF and I-geo values, while Ni and Cd contributed the most to the ecological risk and toxic risk index. The obtained results revealed that Cd and Ni in the sediments may pose a threat to organisms living in Lake Nasser.

2

Accumulation of heavy metals in tilapia fish species and related histopathological changes in muscles, gills and liver of Oreochromis niloticus occurring in the area of Qahr El-Bahr, Lake Al-Manzalah, Egypt

Yacoub Amal M., Mahmoud Soaad A., Abdel-Satar Amaal M.

Oceanological and Hydrobiological Studies

|

2021

|

Vol. 50, No. 1

1--15

EN

Accumulation of metals (Fe, Zn, Cu, Mn, Pb, Cd and Ni) in the muscles and gills of Oreochromis niloticus, Oreochromis aureus and Tilapia zillii was assessed based on seven locations in the Qahr El-Bahr area in Lake Al-Manzalah. The average accumulation of metals was in the following order: Tilapia zillii > Oreochromis aureus > Oreochromis niloticus. To determine the risk of fish consumption, the estimated daily intake, carcinogenic, non-carcinogenic and relative risk indices were calculated. The results indicate that the intake of individual metals through the consumption of fish is almost safe for human health, whereas the intake of combined metals poses a high potential health risk to consumers. Assessment of carcinogenic risk of Cd and Ni from the consumption of tilapia species indicates that consumers are at risk of cancer. The contribution of Pb and Cd to the overall relative risk index ranged from 34% to 41%. Of the three species studied, Oreochromis niloticus is relatively safe for consumption as it poses the least health hazard, while Tilapia zillii is more predisposed to accumulate metals in its tissues. Histopathological changes were observed in the muscles, gills and liver of Oreochromis niloticus as a result of heavy metal accumulation in these organs.

3

Risk assessment of heavy metal pollution in water, sediment and plants in the Nile River in the Cairo region, Egypt

Al-Afify Afify D.G., Abdel-Satar Amaal M.

Oceanological and Hydrobiological Studies

|

2020

|

Vol. 49, No. 1

1--12

EN

Samples of water, sediment and two native plants (Eichhornia crassipes and Ceratophyllum demersum), collected seasonally from eight sites, were analyzed to investigate the level of contamination with metals (Fe, Mn, Ni, Co, Zn, Cu, Cr, Pb and Cd) in the Nile River in the Cairo region, using heavy metal pollution and contamination indices in the case of water, and the geoaccumulation index, the pollution load index, the enrichment factor and the potential ecological risk factor in the case of sediment. The results clarified that the levels of metals among three compartments were in order: sediments > plants > water. The Nile water in Cairo is not critically polluted by the studied metals and the metal pollution index for most sites does not exceed the critical limit (< 100). Sediment samples showed a clear accumulation of Mn, Ni and Cd when compared with benchmarks cited by the Environmental Protection Agency (EPA), especially during low flow seasons. The contribution of Cd to the ecological risk assessment was about 80%, while the contribution of Ni was about 10%, reflecting that these elements originated primarily from anthropogenic sources. Eichhornia crassipes and Ceratophyllum demersum have a higher accumulation capacity for Mn, Cu and Fe compared to the other studied metals.