Assessment of trace element occurrence in Nile Tilapia from the Rosetta branch of the River Nile, Egypt: Implications for human health risk via lifetime consumption.

River pollution can harm human health through direct contact, drinking water, and the consumption of contaminated fish and irrigated agricultural products. Surface water and Nile tilapia (Oreochromis niloticus) samples were collected monthly from July 2022 to June 2023 at three sites (El-Rahawy, Sabal, and Tala) along the Rosetta Nile branch in Egypt to monitor the presence of eight trace elements. The potential human health risks from consuming contaminated fish were also assessed. Iron and manganese were consistently detected in all water samples across most seasons and locations, with concentrations generally below the WHO permissible levels. All 72 analyzed fish muscle samples were found to contain trace elements. The mean concentrations of metals in the fish muscle samples, in descending order, were: iron > zinc > copper > manganese > tin > antimony > lead > mercury. Significant spatial and seasonal variations were observed in both water and fish samples. El-Rahawy was identified as the most contaminated site, with summer exhibiting the highest contamination rate compared to other seasons. Fish samples collected from El-Rahawy demonstrated the highest bioconcentration factor (BCF) values for most elements, particularly mercury, lead, iron, manganese, and antimony. Target hazard quotient (THQ) calculations for the trace elements in Nile tilapia muscles revealed that all trace elements, except antimony, had THQ values below 1, suggesting that consuming Nile tilapia from these sites is unlikely to cause adverse health effects. However, THQ values for antimony exceeded the threshold of 1, indicating a potential health risk for consumers. Although the detected trace elements in the fish were below the permissible toxicity limits, some could pose a future threat to human health, necessitating further studies, ongoing monitoring, and preventive measures.

Occurrence and ecotoxicological risk assessment of pesticides in sediments of the Rosetta branch, Nile River, Egypt.

This study aimed to (1) monitor the occurrence and spatiotemporal variations of 100 pesticides in sediments collected monthly from July 2018 to June 2019 from sampling sites in El-Rahawy, Sabal, and Tala, along the Rosetta branch of the Nile River, Egypt, and (2) perform an ecological risk assessment for aquatic organisms upon exposure to the detected sediment pesticides based on the risk quotient (RQ) method. Out of the 100 pesticides monitored, 16 pesticides belonging to seven chemical families were detected, and 55% of the sediment samples were contaminated with one or more pesticide residues. The mean concentration (mg/kg dry weight (dw)) and detection frequency (%) of the four most frequently detected pesticides in the sediment samples were as follows: chlorpyrifos (0.18 mg/kg dw and 34%), p,p'-DDE (0.018 mg/kg dw and 30%), cypermethrin (0.03 mg/kg dw and 14%), and deltamethrin (0.026 mg/kg dw and 13%). The spatial distribution exhibited that El-Rahawy had the highest pesticide load (2.86 mg/kg dw) among the studied sites, whereas the temporal variations revealed that the highest total pesticide concentrations were detected in winter season (1.73 mg/kg dw). Meanwhile, 12 pesticides showed high RQs (>1), posing a potential ecological risk to aquatic species that live and feed on such sediments.

Occurrence, human health, and ecotoxicological risk assessment of pesticides in surface waters of the River Nile's Rosetta Branch, Egypt.

In Egypt, the shortage of freshwater resources and their pollution constitutes a growing concern. Therefore, the objectives of this study were to (i) monitor the occurrence and spatiotemporal variations of 100 pesticides in surface water samples collected monthly (from July 2018 to June 2019) from El-Rahawy, Sabal, and Tala sampling sites along the Rosetta branch of the River Nile in Egypt, (ii) identify potential non-carcinogenic health risks for the local people through the lifetime consumption of contaminated drinking water, and (iii) perform an ecological risk assessment of aquatic organisms upon exposure to pesticides detected in surface waters based on the risk quotients (RQs) method. Of the 100 pesticides analyzed, 22 belonging to 11 chemical families were detected, and 75.5% of surface water samples were contaminated with one or more pesticide residues. The most frequently detected pesticide was malathion (57%), followed by chlorpyrifos (54%), atrazine (23%), and carbendazim (20%). Spatial distribution showed that the El-Rahawy site had the highest pesticide load (38.47 µg/L), and Sabal had the lowest (16.29 µg/L). Temporal variations revealed that the highest total pesticide concentrations were detected in summer (27.98 µg/L) compared to spring (23.16 µg/L), winter (19.18 µg/L), and autumn (11.85 µg/L). For non-carcinogenic risks of pesticides detected in surface water, the target hazard quotient (THQ) values were less than one. This implies that there is no potential human risk from exposure to drinking water at the sites under study. However, 13 pesticides presented high-risk quotients (RQ > 1), posing potential ecological risks to aquatic organisms.

Occurrence and human health risks of pesticides and antibiotics in Nile tilapia along the Rosetta Nile branch, Egypt.

Nile tilapia (Oreochromis niloticus) samples were collected at monthly intervals between July 2018 and June 2019 from 3 sampling sites (El-Rahawy, Sabal and Tala) situated along the Rosetta branch of the Nile, Egypt, to monitor the presence of 100 pesticides and 5 antibiotics using different extraction procedures followed by GC-MS/MS and LC-MS/MS. Potential human health risks via the consumption of contaminated fish was also assessed. Of the 72 analyzed fish muscle samples; 86% and 21% were contaminated with pesticides and antibiotics, respectively. Chlorpyrifos (ranging from < LOQ to 0.08 mg/kg) was the most frequently detected pesticide followed by p,p'-DDE (ranging from < LOQ to 0.04 mg/kg) in 83 and 45% of the fish muscle samples, respectively. Nitrofurazone (ranging from 8.6 to 52 µg/kg) was the most frequently detected antibiotic, followed by nitrofurantoin (ranging from 1.1 to 2 µg/kg) and chloramphenicol (ranging from < LOQ to 0.17 µg/kg). These antibiotics were found in 12, 6 and 5% of the fish muscle samples, respectively. The spatial distribution of the detected pesticides and antibiotics in fish samples along the Rosetta branch showed that the highest mean concentrations were found in the Sabal area, followed by samples from Tala and El-Rahawy. An investigation into seasonal variations revealed that the highest mean concentrations of pesticides and antibiotics in fish samples were detected in winter and spring, respectively. According to target hazard quotient (THQ) calculations for the detected pollutants in Nile tilapia muscle, all pollutants gave THQ values lower than 1, indicating that the consumption of this fish from the study sites is unlikely to cause any detrimental effects to consumers.