Estimation of Cadmium in Muscles of Five Freshwater Fish Species from Manzalah Lake, and Possible Human Risk Assessment of Fish Consumption (Egypt).

The Egyptian government devised a plan in 2016 to improve the unique ecological significance of northern lakes, which mentioned Manzalah Lake in the Egypt Vision 2030. In this regard, this study investigated cadmium (Cd) content in five freshwater fish species collected from Manzalah Lake in Egypt at 2018 by local fishermen. According to the findings, Clarias gariepinus recorded the highest concentration of Cd (1.40 ± 0.2 µg/g) and the lowest concentration was recorded in O. aureus (1.19 ± 0.2 µg/g). Cadmium contents of all species were largely above the permissible level of the Food Agricultural Organization (FAO)/World Health Organization (WHO) and Commission Regulation (EC). The estimated daily intake (EDI), the estimated weekly intake (EWI), and the percentages of provisional tolerable weekly intake (PTWI %) values for Cd in the C. gariepinus > Sarotherodon galilaeus > Tilapia zillii > Oreochromis niloticus > Oreochromis aureus which consumed by children, teenagers, and adults were much higher than the PTWI values established by FAO/WHO. In addition, C. gariepinus consumed by children showed the highest value of the target hazard quotient (THQ) (5.83 a day or 40.81 a week) while O. aureus that ingested by adults showed the lowest level (1.06 a day or 7.42a week). The target carcinogenic risk (TCR) of C. gariepinus in children had the greatest level (2.21 × 10-3 a day or 1.55 × 10-2 a week), whereas O. aureus in adults had the lowest level of TCR (4 × 10-4 a day or 2.81 × 10-3 a week). THQs values of Cd in the five studied species were found higher than one. Moreover, TCRs values of Cd in the five species were exceeded the US Environmental Protection Agency guideline USEPA permissible limits suggesting that a daily or weekly consumption of these species could lead to a high risk non-carcinogenic and carcinogenic for humans.

Genotoxicity and Trace Elements Contents Analysis in Nile Tilapia (Oreochromis niloticus) Indicated the Levels of Aquatic Contamination at Three Egyptian Areas.

The toxic waste and pollutants of heavy metals continuously pollute freshwater aquatic reservoirs, which have severe implications on aquatic life and human health. The present work aims to evaluate trace elements (Zn, Mn, Cu, Cd, and Pb) along with three sites, Mariout Lake, Abbassa, and River Nile Aswan in Egypt, using Nile tilapia (Oreochromis niloticus) as bioindicator. The quality assurance, health-risk assessment, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), quantitative polymerase chain reaction (qPCR), and micronucleus test were performed to investigate the effect of different trace elements on Hsp70 gene level and micronuclei formation. We observed the highest expression of Hsp70 protein band of 70 KD and stress-responsive Hsp70 gene in the liver followed by gills of Nile tilapia caught from Mariout and Abbassa, but the lowest expression was in Nile tilapia caught from Aswan. Obvious micronuclei were observed under the microscope in erythrocytes, and their number was gradually decreased in the following manner: Mariout > Abbassa > Aswan. Noticeably, Cu, Zn, and Mn contents were low. Still, Pb and Cd contents were higher than the toxicity level recommended by the Food and Agriculture Organization (FAO), The World Health Organization (WHO), and the European Commission (EC). These results showed that Hsp70's appearance at the two levels of mRNA and protein is an effective indicator for aquatic pollution besides the aberration at the chromosome level represented in the micronucleus test. Furthermore, these results showed that Nile tilapia of the Aswan region had comparatively low trace elements contamination and were suitable for consumption.

Trace elements exposure influences proximate body composition and antioxidant enzyme activities of the species tilapia and catfish in Burullus Lake-Egypt: human risk assessment for the consumers.

The trace elements concentration in the fish estimates the contamination degree in the aquatic environment. These toxic trace elements are transported into the human through the consumption of polluted fish. This study estimated the effect of Cd, Hg, Pb, As, and Al on tilapia species and catfish Clarias gariepinus (six for each species of fish) inhabiting Burullus Lake-Egypt 30° 33'-31° 08' E and 30° 22'-31° 35' N. The highest Pb concentrations recorded in the muscle of C. gariepinus 2.29 ± 0.29 µg/g while S. galilaeus was estimated the lowest Hg concentration of 0.54 ± 0.02 µg/g which indicated the presence of contaminants exceeded the limits permitted by FAO/WHO and EC. The maximum mean carbohydrate, lipid, and protein recorded in O. niloticus 18.66, 16.33, and 58.16 mg/g, respectively; moisture in O. aureus 67.33%; and ash 16.41% in O. niloticus. The lowest amount of carbohydrate was recorded in the T. zillii 14.1 mg/g, lipid, and ash in C. gariepinus 11.65 mg/g and 3.375%, respectively. Protein and moisture in the S. galilaeus were 53.75 mg/g and 60.75%, respectively. The results recorded a marked insignificant (P > 0.05) decrease in CAT, GR, and GPx activity in O. niloticus. GSH and SOD activity was an insignificant (P > 0.05) decrease in C. gariepinus. The results concluded that the trace elements concentrations exceed the maximum permissible limits recommended in fish samples set by Egypt, FAO, WHO, and EC. The estimated weekly intake of all elements through consumption of studied fish species inhabiting Burullus Lake by a child (15 kg) in Egypt is well above the PTWI recommended by FAO/WHO, whereas it is well below the PTWI for human consumption by young people (40 kg) and adult person (70 kg), at least in respect of residual levels of studied elements excluding Cd and Hg. Thus, for consumer protection, these fish species are unsafe and have hazardous effects for children, and about youth and adult consumption, caution must be taken to consider individuals eating significant amounts of fish.

Correction to: Trace elements exposure influences proximate body composition and antioxidant enzyme activities of the species tilapia and catfish in Burullus Lake-Egypt: human risk assessment for the consumers.

The correct images of figs. 2 and 3 are presented in this paper.