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Molluscs, owing to their filtrate ability, can accumulate metals that may contaminate food, causing a negative impact on the health of the consumers. Thus, the main objective of the present study was to investigate the heavy metal concentrations in one of the widest broad and consumed surf clams Mactra olorina available in the Great Bitter Lake, Egypt. The concentrations of the heavy metals (Pb, Cd, Cu, and Zn) were seasonally evaluated in water, sediment, and the soft flesh of M. olorina. The specimens were monthly collected from the Egyptian Great Bitter Lake near Fayed City (Ismailia Governorate) for one year, from April 2009 to March 2010. Results revealed that, the annual mean concentrations of heavy metals in water were 1.376±0.562, 0.267±0.329, 2.256±2.909 and 3.355±2.731 μg/l for Pb, Cd, Cu and Zn, respectively. The corresponding concentration values in the sediment were 0.398±0.355, 0.307±0.244, 1.753±0.464 and 8.643±1.821 for Pb, Cd, Cu and Zn μg/g, respectively. While, the annual mean concentrations of heavy metals in soft tissues were 0.538±1.130, 0.262±0.283, 5.395±3.115 and 13.043±5.743 for Pb, Cd, Cu, and Zn μg/g, respectively. Interestingly, heavy metals deposited in the tissues of M. olorina and their environment (water and sediments) recorded a close relationship (0.05 ≥ p ≤0.01) in the current research. In conclusion, though no apparent risk was detected on bivalve consumers from being exposed to a single metal, yet there is a risk from being exposed to the 4 studied metals combined together, especially for high bivalve-consuming groups such as fishermen. Furthermore, environmental parameters need to consider when to use bivalves as indicators of heavy metal pollution since seasonality could affect the absorption of heavy metals. [ABSTRACT FROM AUTHOR]

In aquatic ecosystem biomonitoring, the use of biota and their habitat provides a good indication of conditions and potential threats to any water body. The potential for heavy metal poisoning in humans because of consuming tainted fish has gotten a lot of press around the world. Heavy metal pollutants in water are mostly caused by human activities such as waste disposal, organic fuel combustion, phosphate fertilizers, plastics, and pesticides. The aim of this study was to see how much heavy metals contamination there was in Nile tilapia Oreochromis niloticus and how physicochemical characteristics affected the biomarkers. Heavy metals accumulation (cadmium, lead, zinc, copper, and iron) was studied on the serological indices of a freshwater fish O. niloticus. Fish, water, and sediments were collected at three locations along the Nile River. The findings of this study showed a significant difference in water quality indices in response to pollution levels among the sites studied. Consequently, the current results confirm that the distribution of heavy metals in tissues could potentially deteriorate biochemical parameters of O. niloticus. [ABSTRACT FROM AUTHOR]