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

Carbon nanomaterials for co-removal of antibiotics and heavy metals from water systems: An overview

Pollution resulting from the combination of antibiotics and heavy metals (HMs) poses a significant threat to human health and the natural environment. Adsorption is a promising technique for removing antibiotics and HMs owing to its low cost, simple procedures, and high adsorption capacity. In recent years, various novel carbon nanomaterials have been developed, demonstrating outstanding performance in simultaneously removing antibiotics and HMs. This work presents a comprehensive review of carbon nanomaterials (i.e., carbon nanotubes, graphene, resins, and other nanocomposites) for the co-removal of antibiotics and HMs in water systems. The mechanisms influencing the simultaneous removal of antibiotics and HMs include the bridging effect, electrostatic shielding, competition, and spatial site-blocking effects. These mechanisms can promote, inhibit, or have no impact on the adsorption capacity for antibiotics or HMs. Additionally, environmental factors such as pH, inorganic ions, natural organic matter, and microplastics affect the adsorption efficiency. This review also covers adsorbent regeneration and cost estimation. On the laboratory scale, the cost of the adsorption process primarily depends on the chemical and energy costs of adsorbent production. Our assessment highlights that the carbon-nanomaterial-mediated simultaneous removal of antibiotics and HMs warrants comprehensive consideration from both economic and environmental perspectives.

Enhanced Detection of Enrofloxacin in Seawater Using a Newly Selected Aptamer on a Graphite Oxide-Based Biosensor

Developing aptasensors offers several advantages including sensitivity, selectivity, cost-effectiveness, and speed over traditional analytical techniques for antibiotic detection. We have successfully identified Enro_ap3, a 30-mer enrofloxacin-binding aptamer with micromolar binding affinity, through an optimized Capture-SELEX platform. Compared to other reported enrofloxacin-binding aptamers, this shorter aptamer not only streamlines the design process but also eliminates the common issue of strong nonspecific binding to the GO surface, thereby improving the overall detection capabilities of the biosensor (GO-Enro_ap3-FAM). This GO aptasensor demonstrated remarkable selectivity by effectively distinguishing enrofloxacin from different structurally diverse antibiotics. The sensor boasts a LOD of 32.15 μg/mL, 2.5 times more sensitive than the original 30-mer, with recoveries of 74%-92% and relative standard deviations of 6.3%-12.5% in seawater samples spiked with enrofloxacin. Furthermore, the GO aptasensor's detection capabilities were found to be on par with traditional LC-MS/MS techniques, exhibiting no significant differences in recovery rates even in complex matrices. The sensor's performance remained consistent across variations in salinity, acidity, and total organic carbon concentrations in seawater samples collected from different locations, underlining its robustness in diverse environmental conditions and its suitability for real-world seawater monitoring applications. Our findings highlight the importance of the aptamer's chain length and its binding affinity toward the target after immobilization on the GO substrate. These factors significantly impact the performance of GO aptasensors in seawater. Overall, the GO aptasensor provides a well-balanced approach, combining sensitivity, environmental adaptability, and practical usability for detecting pharmaceutical contaminants, such as antibiotics, in marine environments.

Exposure assessment of pesticide residues, heavy metals, and veterinary drugs through consumption of Egyptian fish samples

Environmental contaminants may enter seafood products either through water and sediments or via feed and feed additives or may be introduced during fish processing and storage. The study focused on the nutritional and toxicological significance of heavy metals, antibiotics, and pesticide residues in 48 fish samples collected from the Kafr-ElSheikh governorate in Egypt. Various analytical instruments are used to determine and detect heavy metals, antibiotics, and pesticides. These include Liquid Chromatography Tandem Mass Spectrometer (LC-MS/MS), Inductively Coupled Plasma Mass Spectrometer (ICP-MS), and Gas Chromatography-Mass Spectrometer (GC-MS). The following metals were discovered in fish species: arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), and zinc (Zn). Each of these metals was detected 47 times. Chromium (Cr) was detected 40 times, nickel (Ni) was detected 27 times, and lead (Pb) was detected 6 times. The mean concentrations of As, Cd, Cr, Co, Cu, Fe, Ni, Mn, Hg, Pb, and Zn were determined to be 0.025, 0.02, 0.501, 0.50, 0.81, 12.56, 0.5, 0.689, 0.051, 0.031, and 5.78 mg/kg, respectively. All levels of cadmium, mercury, and lead detected in fish samples were significantly lower than the maximum permissible limits set by Egyptian and European standards. Furthermore, in this study, antibiotics and pesticide residues were found to be not detected in all analyzed fish samples. Based on the estimated daily intake and hazard quotient values, the concentration levels of metals found in fish samples seem to pose no significant threat to public health.

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.

Physical and chemical food safety hazards and associated health risks in seafood: A Mediterranean perspective (Part 1)

Several risks to food safety are associated with seafood. The marine environment is heavily affected by various materials, both of physical and chemical nature, which have significant impact on the safety of seafood. Recently, there has been a concerning discovery regarding seafood contamination. As it appears, there are physical hazards present, specifically in the form of nano- and micro-plastic materials. Additionally, chemicals from various sources have been detected. These chemicals are commonly used in the production of convenience goods, antimicrobials, antibiotics, heavy metals and industrial effluents. This chapter has focused on the various hazards that can influence the safety of seafood in the marine environment. It covers both physical and chemical sources of these hazards, ensuring a comprehensive understanding of the potential risks involved. There are indications that the consumption of polluted seafood in the Mediterranean region can have negative impact on human health.

An integrated deep learning approach for modeling dissolved oxygen concentration at coastal inlets based on hydro-climatic parameters

Climate change has a significant impact on dissolved oxygen (DO) concentrations, particularly in coastal inlets where numerous human activities occur. Due to the various water quality (WQ), hydrological, and climatic parameters that influence this phenomenon, predicting and modeling DO variation is a challenging process. Accordingly, this study introduces an innovative Deep Learning Neural Network (DLNN) methodology to model and predict DO concentrations for the Egyptian Rashid coastal inlet, leveraging field-recorded WQ and hydroclimatic datasets. Initially, statistical and exploratory data analyses are performed to provide a thorough understanding of the relationship between DO fluctuations and associated WQ and hydroclimatic stressors. As an initial step towards developing an effective DO predictive model, conventional Machine Learning (ML) approaches such as Gaussian Process Regression (GPR), Support Vector Regression (SVR), and Decision Tree Regressor (DTR) are employed. Subsequently, a DLNN approach is utilized to validate the prediction capabilities of the investigated conventional ML approaches. Finally, a sensitivity analysis is conducted to evaluate the impact of WQ and hydroclimatic parameters on predicted DO. The outcomes demonstrate that DLNN significantly improves DO prediction accuracy by 4% compared to the best-performing ML approach, achieving a Correlation Coefficient of 0.95 with a root mean square error (RMSE) of 0.42 mg/l. Solar radiation (SR), pH, water levels (WL), and atmospheric pressure (P) emerge as the most significant hydroclimatic parameters influencing DO fluctuations. Ultimately, the developed models could serve as effective indicators for coastal authorities to monitor DO changes resulting from accelerated climate change along the Egyptian coast.

Biofiltering capacity of Chambardia rubens (Bivalvia: Unionidae) may modulate expression of stress and growth genes inhibited by the neonicotinoid insecticide acetamiprid in zebrafish

Neonicotinoid insecticides specifically target insect subtypes of nicotinic acetylcholine receptors. Acetamiprid (ACE: C10H11ClN4), the neonicotinoid insecticide, is used to control crop insect pests worldwide. It is a nitrile, monochloropyridine, and carboxamidine that is highly soluble and accessible to waterways. There, it causes neurotoxic and oxidative perturbance to non-target organisms. The unionid mussel Chamabradia rubens is a common Northern River Nile suspension feeder. The current study aimed to assess ACE filtration from waters by C. rubens, and whether this biological power can reduce ACE effects on fish. Removal of ACE by C. rubens was assessed using LC-MS/MS. Zebrafish Danio rerio adults were exposed to different sublethal doses of ACE in the presence or absence of C. rubens in their aquaria. The results showed that mussels could remove significant ACE amounts from water, where it accumulated mostly in the digestive gland. The presence of C.rubens in zebrafish aquaria having ACE was accompanied by significant upregulation of antioxidant enzyme gene transcripts and total H2O2 scavenging, in contrast to mussel-free ACE-exposed groups. Meanwhile, liver triglycerides rose 5-6-fold in response to ACE in the "Fish-Only" groups, indicating an ACE-induced hepatotoxicity. Also, Insulin-like growth factor 1 (igf1) and fish body mass increased more in "Fish + Mussel" groups than in the "Fish-Only" ones. In aggregate, these findings suggest that the Nile mussel could reduce the oxidative stress and metabolic changes induced in fish by ACE. This can contribute valuable environmental and economic benefits upon the use of this mussel as a biofilter.

Assessment and Assay Comparison for Detection of Antimicrobial Residues in Freshwater Aquaculture Fish in Erbil Governorate, Iraq

The excessive and uncontrolled application of antibiotics in the fish farming industry, coupled with a lack of health monitoring and medication practices, is a driving force behind the escalating development of antimicrobial resistance. The present study assessed and compared qualitative field diffusion (QFD) and disk diffusion (DD) assays for the detection of antimicrobial residues (ARs) in diverse freshwater aquaculture fish. A total of 380 freshwater aquaculture fish (160 fresh and 180 frozen) samples were systematically collected between January and June 2021 from various retail stores located in Erbil Governorate, Iraq. Based on QFDA results, overall, ARs were detected (52; 15.3%) at a relatively lower frequency with comparatively higher frequency (21; 31.1%) in fresh than (31; 17.2%) frozen fish samples. On the other hand, DDA also revealed a comparable (45; 13.2%) prevalence rate of ARs. However, a low detection was observed more in fresh (17; 10.6%) than frozen (28; 15.6%) fish samples. Moreover, no statistically significant disparity (χ2 = 0.069; p = 0.79) between two assays and types of fish was recorded. In conclusion, the results of the present study showed that detecting a considerable frequency of ARs in these fish samples raises concerns about potential threats to public health. This underscores the necessity for understanding antibiotic application in aquaculture and its potential connection to antibiotic resistance in bacterial pathogens. Such comprehension is pivotal for formulating and implementing effective control and farm management strategies to address this pressing issue.

Review of the Terminology, Approaches, and Formulations Used in the Guidelines on Quantitative Risk Assessment of Chemical Hazards in Food

This paper reviews the published terminology, mathematical models, and the possible approaches used to characterise the risk of foodborne chemical hazards, particularly pesticides, metals, mycotoxins, acrylamide, and polycyclic aromatic hydrocarbons (PAHs). The results confirmed the wide variability of the nomenclature used, e.g., 28 different ways of referencing exposure, 13 of cancer risk, or 9 of slope factor. On the other hand, a total of 16 equations were identified to formulate all the risk characterisation parameters of interest. Therefore, the present study proposes a terminology and formulation for some risk characterisation parameters based on the guidelines of international organisations and the literature review. The mathematical model used for non-genotoxic hazards is a ratio in all cases. However, the authors used the probability of cancer or different ratios, such as the margin of exposure (MOE) for genotoxic hazards. For each effect studied per hazard, the non-genotoxic effect was mostly studied in pesticides (79.73%), the genotoxic effect was mostly studied in PAHs (71.15%), and both effects were mainly studied in metals (59.4%). The authors of the works reviewed generally opted for a deterministic approach, although most of those who assessed the risk for mycotoxins or the ratio and risk for acrylamide used the probabilistic approach.

Assessment of some chemical residues in Egyptian raw milk and traditional cheese

Background

The assessment of risks related to food safety is becoming a challenge in developing countries with its consequent health hazards. Chemical risk assessment in dairy products is important to maintain consumer health locally and internationally. Since milk and dairy products are essential foods for a wide range of customers, mostly children, patients, and pregnant women, it is very important to estimate the risks of some chemical residues, such as pesticides, some heavy metals, and aflatoxins.

Aim

This work aims to determine the levels of chemical contamination in milk and traditional Egyptian cheese.

Methods

Heavy metals were determined in samples by atomic absorption spectrometry. GC-mass spectrometry (MS)/MS and LC-MS/MS were also used for measuring pesticide residues. The Aflatoxin M1 was determined by enzyme-linked immune-sorbent assay.

Results

Raw milk samples were tested and showed elevated concentrations of lead and cadmium, (46% and 4%, respectively). The heavy metals detected in the Egyptian cheese samples were variable depending on the type of cheese. Moreover, p.p.-DDE phenofose was present in 45% and 29% of raw milk and Ras cheese samples, respectively. For Aflatoxin M1, only 7% of milk samples and 2.9% of Ras cheese samples exceeded the acceptable limits.

Conclusion

More surveying and risk assessment of chemical residues in milk and milk products are essential for controlling health risks to consumers.

Health Risk Assessment of Antibiotic Pollutants in Large Yellow Croakers from Zhejiang Aquaculture Sites

Intensive aquaculture combatting the decline of large yellow croaker populations can trigger bacterial outbreaks, resulting in extensive antibiotic use. In this study, we screened 5 aquaculture sites in the coastal areas of Zhejiang and identified 17 antibiotics in large yellow croakers using UPLC-MS/MS. The distribution and occurrence of antibiotic pollutants were different in the different tissues of large yellow croakers, being primarily dominated by quinolones. Relatively higher average residue levels of enrofloxacin and ciprofloxacin were detected in the inedible parts, specifically the gills (37.29 μg/kg). Meanwhile, relatively high average residue levels of enrofloxacin and ciprofloxacin were also found in the edible parts, particularly in the muscle (23.18 μg/kg). We observed that the residue levels detected in the swim bladder exceeded the prescribed limit for fish muscle, but there is currently no specific regulatory limit established for this particular tissue. Despite the HI values of enrofloxacin and ciprofloxacin being below 0.01, the health risks should not be disregarded. The findings of this research provide significant practical implications for assessing antibiotic contamination and enhancing the risk management of coastal regions.

Cocktails of pesticide residues in Prochilodus lineatus fish of the Salado River (South America): First record of high concentrations of polar herbicides

Muscle and viscera (gills-liver) of the fish Prochilodus lineatus were obtained from four sites of lower course of Salado river and one site at Santa Fe river near to its confluence with Salado river from Santa Fe (Argentina) between December 2021 and February 2022. Sediment samples were also obtained from the same sites. All samples were analyzed for pesticide residues following the QuEChERS method to quantify 136 compounds by UHPLC-ESI-MS/MS and GC-EI-MS/MS. Overall, muscle fish tissue showed very high concentrations (maximum concentrations detected) of the insecticide cypermethrin (204 μg/kg), polar herbicides (glyphosate; 187 μg/kg and its degradation product (aminomethylphosphonic acid) AMPA; 3116 μg/kg, and glufosinate-ammonium; 677 μg/kg), and the fungicide pyraclostrobin (50 μg/kg). In viscera samples, high values of cypermethrin (506 μg/kg), chlorpyrifos (78 μg/kg), and lambdacyhalothrin (73 μg/kg) were the main pesticides found. Mean residues concentrations detected among sites were not significantly different neither in muscle nor viscera of P. lineatus in most of the cases. Exceptionally, the southernmost studied site of the Lower Salado river showed significant differences in concentration of residues found in muscle, due to high concentrations of glyphosate and glufosinate-amonium (KW = 11.879 and KW = 13.013, respectively, P < 0.05). Other norther Lower Salado river site showed significant higher AMPA concentration in fish viscera than in the rest of the studied sites (KW = 12.86 P < 0.05). Some sediment samples showed low levels of herbicides such as glyphosate (24 μg/kg) and fungicides. However, the world highest levels of polar herbicides were recorded in fish muscle. The results of this study highlight the need for periodic monitoring due to the high concentration of pesticides and its potential risk in a very important commercial freshwater fish from Argentina, which is consumed locally and exported to other countries for human consumption.

Evaluating the spatial and temporal distribution of emerging contaminants in the Pearl River Basin for regulating purposes

Little information is available on how the types, concentrations, and distribution of chemicals have evolved over the years. The objective of the present study is therefore to review the spatial and temporal distribution profile of emerging contaminants with limited toxicology data in the pearl river basin over the years to build up the emerging contaminants database in this region for risk assessment and regulatory purposes. The result revealed that seven groups of emerging contaminants were abundant in this region, and many emerging contaminants had been detected at much higher concentrations before 2011. Specifically, antibiotics, phenolic compounds, and acidic pharmaceuticals were the most abundant emerging contaminants detected in the aquatic compartment, while phenolic compounds were of the most profound concern in soil. Flame retardants and plastics were the most frequently studied chemicals in organisms. The abundance of the field concentrations and frequencies varied considerably over the years, and currently available data can hardly be used for regulation purposes. It is suggested that watershed management should establish a regular monitoring scheme and comprehensive database to monitor the distribution of emerging contaminants considering the highly condensed population in this region. The priority monitoring list should be formed in consideration of historical abundance, potential toxic effects of emerging contaminants as well as the distribution of heavily polluting industries in the region.

Health Risk Assessment of Pesticide Residues in Drinking Water of Upper Jhelum Region in Kashmir Valley-India by GC-MS/MS

Globally growing demand for agricultural and farm foods has more or less become dependent on chemical pesticides to maintain the supply chain, which undoubtedly boosts agricultural production. However, pesticides not only impact the target pests but cause hazard to human health. Pesticides are ubiquitous and can be found in almost every component of the environment. They can therefore impair human and biota health when present over the threshold level. The present study assessed the concentration of commonly used pesticides for agricultural purposes but get mixed in different sources of water, as such fifteen sampling sites along the upper Jhelum basin of Kashmir valley were chosen. For the analysis, 60 water samples were obtained from different water sources. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to determine pesticide residues in water samples. Pesticide residues from 10 of the 26 commonly used pesticides were detected in water samples. Difenoconazole had the highest concentration among the pesticides detected, with a mean concentration of 0.412 ± 0.424 μg/L ranging from 0.0 μg/L to 0.8196 μg/L. The target hazards quotient (THQ) was used to quantify the possible noncarcinogenic health risks associated with drinking pesticide-contaminated water. Only chlorpyrifos and quinalphos were detected >1 in RWS3 (1.6571), RWS4 (1.0285), RWS14 (1.2571), and RWS15 (1.2000) sample sites, implying that the drinking water poses a health risk to humans. Hence, pesticide hazards should be mitigated and rigorous monitoring is needed to reduce pesticide residues in drinking water.

Occurrence, spatio-temporal distribution, and human health risk assessment of pesticides in fish along the Ayuquila-Armería River, Mexico

Pesticide usage has contributed to increasing food production; it has also caused them to be found in ecosystems inducing adverse effects on biota. Fish are the most abundant and diverse vertebrates in the world and are of great importance both economically and ecologically. Some fishes are indicators of the environmental quality of aquatic ecosystems and provide insight as to how pollutants might influence public health. The tilapias species can be considered biomonitors because they present little displacement representing the contamination level of a site. This study aimed at three goals: (1) to determine the concentration of 20 pesticides in tilapia muscle in the Ayuquila-Armería basin, (2) to describe the spatiotemporal variation of analytes and (3) to evaluate the risk of consuming contaminated fish. The presence of 11 pesticides was determined. Ametrine, glyphosate and malathion concentrations showed significant differences by season. The risk assessment showed that the consumption of tilapia muscle from the Ayuquila-Armería basin does not represent a risk for the population. Diazinon concentrations were relatively low compared to the other pesticides concentrations, but its toxic characteristics were the ones that most negatively influenced the risk assessment. The results obtained are relevant from the social and economic points of view.

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.

Pesticide residues in Rita rita and Cyprinus carpio from river Ganga, India, and assessment of human health risk

•

Accumulation of pesticide residues in fish due to continuous use in agricultural areas along river Ganga basin.

•

Residues concentrate in the humans through consumption of food from the river.

•

Health impacts like non-carcinogenic (THQ) and carcinogenic (R) risks are never negligible by these residues.

Present study was carried out to determine the concentration and bioaccumulation of pesticide residues in two commonly edible fishes: bagrid fish, Rita rita and common carp, Cyprinus carpio collected from river Ganga at Narora, India. The human health risk via consumption of these fishes was also assessed. The n-hexane extract of the muscle tissues was characterized by gas chromatography coupled to mass spectrometry and quantified by electron capture detector for pesticide residues. Bioaccumulation factor (BAF) in bagrid fish for detected pesticides was found to be higher than those in common carp. Estimated daily intake (EDI) values in our study were insignificantly higher than Average daily intake (ADI) values. Target hazard quotient (THQ) via consumption of selected fishes was found to be lower than the set 1.0, inferring non-carcinogenic risk. With regard to contaminants carcinogenic effects the total risk ratio (R) values of each pesticide was found lower than threshold risk limit except of heptachlor which indicates carcinogenic risk. The results justify pesticide pollution in river Ganga at Narora and thus more attention is required in order to help improve the health status of this ecosystem and reduce contamination of fishes.

Different antibiotic profiles in wild and farmed Chilean salmonids. Which is the main source for antibiotic in fish?

Fish from both aquaculture and wild capture are exposed to veterinary and medicinal antibiotics (ABs). This study explored the occurrence and probable source of 46 antibiotic residues in muscle of farmed salmon and wild trout from Chile. Results showed that at least one AB was detected in all studied samples. Diverse patterns were observed between farmed and wild specimens, with higher ABs concentrations in wild fish. Considering antimicrobial resistance, detected ABs corresponded to the categories B (Restrict), C (Caution) and D (Prudence) established by Antimicrobial Advice Ad Hoc Expert Group (European Medicines Agency). Multivariate statistic was used to verify differences between farmed and wild populations, looking for the probable source of ABs as well. Principal components analysis (PCA) revealed that ciprofloxacin, moxifloxacin, enrofloxacin, amoxicillin, penicillin G, oxolinic acid, sulfamethoxazole, trimethoprim and clarithromycin were associated with wild samples, collected during the cold season. Conversely, norfloxacin, sulfaquinoxaline, sulfadimethoxine, nitrofurantoin, nalidixic acid, penicillin V, doxycycline, flumequine, oxacillin, pipemidic acid and sulfamethizole were associated with wild samples collected during the warm season. All farmed salmon samples were associated with ofloxacin, tetracycline, cephalexin, erythromycin, azithromycin, roxithromycin, sulfabenzamide, sulfamethazine, sulfapyridine, sulfisomidin, and sulfaguanidine. In addition, linear discriminant analysis showed that the AB profile in wild fish differ from farmed ones. Most samples showed ABs levels below the EU regulatory limit for edible fish, except for sulfaquinoxaline in one sample. Additionally, nitrofurantoin (banned in EU) was detected in one aquaculture sample. The differences observed between farmed and wild fish raise questions on the probable source of ABs, either aquaculture or urban anthropic activities. Further research is necessary for linking the ABs profile in wild fish with the anthropic source. However, to our knowledge, this is the first report showing differences in the ABs profile between wild and aquaculture salmonids, which could have both environmental and health consequences.

Investigating the Effect of an Oxytetracycline Treatment on the Gut Microbiome and Antimicrobial Resistance Gene Dynamics in Nile Tilapia (Oreochromis niloticus)

Antibiotics play a vital role in aquaculture where they are commonly used to treat bacterial diseases. However, the impact of antibiotic treatment on the gut microbiome and the development of antimicrobial resistance in Nile tilapia (Oreochromis niloticus) over time remains to be fully understood. In this study, fish were fed a single treatment of oxytetracycline (100 mg/kg/day) for eight days, followed by a 14-day withdrawal period. Changes in the distal gut microbiome were measured using 16S rRNA sequencing. In addition, the abundance of antimicrobial resistance genes was quantified using real-time qPCR methods. Overall, the gut microbiome community diversity and structure of Nile tilapia was resilient to oxytetracycline treatment. However, antibiotic treatment was associated with an enrichment in Plesiomonas, accompanied by a decline in other bacteria taxa. Oxytetracycline treatment increased the proportion of tetA in the distal gut of fish and tank biofilms of the treated group. Furthermore, the abundance of tetA along with other tetracycline resistance genes was strongly correlated with a number of microbiome members, including Plesiomonas. The findings from this study demonstrate that antibiotic treatment can exert selective pressures on the gut microbiome of fish in favour of resistant populations, which may have long-term impacts on fish health.

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.

Bioconcentration and Metabolism of the New Herbicide Methiozolin in Ricefish (Oryzias latipes)

Methiozolin is a novel herbicide used to control annual bluegrass. It has low vapor pressure and high hydrophobicity, which could result in persistence in water and bioaccumulation. We measured the bioconcentration factors (BCFs) of methiozolin in ricefish (Oryzias latipes). Two radiolabels were used to quantify the parent compound and identify its metabolites. Ricefish were exposed to 2.0 and 20.0 ng/L methiozolin for 28 days in the uptake phase with a 96-h LC₅₀ of 2.2 mg/L(95% confidence limit: 2.1-2.5 mg/L) and water solubility of 4.2 mg/L after 48 h was observed. On the basis of total radioactivity residues (TRRs), BCF_ss and BCF_k values of 797.0-851.9 and 992.9-1077.4 were observed, respectively, while BCF_ss values for methiozolin were 251.9-257.5. Several minor metabolites with TRR < 3.4% were detected. Among them, 4-(2,6-difluorobenzyloxy-methyl)-3-hydroxy-3-methyl-1-(3-methylthiophen-2-yl)butan-1-one, 2,6-difluorobenzyl alcohol, and 4,5-dihydro-5-methyl-3-(3-methylthiophen-2-yl)isoxazol-5-yl)methanol were identified. Methiozolin is metabolized into numerous minor metabolites with potentially low bioaccumulation capacity in ricefish. These findings can facilitate risk assessments regarding methiozolin use, particularly its movements and final stages in aquatic environments.

Heavy metals bioaccumulation in marine cultured fish and its probabilistic health hazard

In aquacultures, heavy metals could be accumulated in fish tissues from natural and human-related sources depending on different factors. This study aims to estimate the level of bioaccumulation of heavy metals in cultured Gilt-head sea bream Sparusaurata. In this regard, heavy metals concentrations were measured in both water and fish musculature that were collected from a private fish farm in Kafr ElSheikh, Egypt. Regarding the water samples, heavy metals were within the permissible limits with exception of Cd, Cu, and Zn. In fish musculature, all heavy metals were within the WHO/FAO permissible limits. The bioaccumulation factor (BAF) indicated that mostly all heavy metals accumulation in the Gilt-head sea bream musculature decreased with time which may be correlated with the increase in water pH, calcium, and other cations concentrations. The hazard index (HI) calculations indicate no adverse health effects of heavy metals on humans through daily fish consumption so far. However, health risks are not negligible making the regular monitoring of metal contaminants in the studied area a necessity.

Co-Treatment of Copper Oxide Nanoparticle and Carbofuran Enhances Cardiotoxicity in Zebrafish Embryos

The use of chemicals to boost food production increases as human consumption also increases. The insectidal, nematicidal and acaricidal chemical carbofuran (CAF), is among the highly toxic carbamate pesticide used today. Alongside, copper oxide nanoparticles (CuO) are also used as pesticides due to their broad-spectrum antimicrobial activity. The overuse of these pesticides may lead to leaching into the aquatic environments and could potentially cause adverse effects to aquatic animals. The aim of this study is to assess the effects of carbofuran and copper oxide nanoparticles into the cardiovascular system of zebrafish and unveil the mechanism behind them. We found that a combination of copper oxide nanoparticle and carbofuran increases cardiac edema in zebrafish larvae and disturbs cardiac rhythm of zebrafish. Furthermore, molecular docking data show that carbofuran inhibits acetylcholinesterase (AChE) activity in silico, thus leading to impair cardiac rhythms. Overall, our data suggest that copper oxide nanoparticle and carbofuran combinations work synergistically to enhance toxicity on the cardiovascular performance of zebrafish larvae.

Sub-lethal effects of organophosphates and synthetic pyrethroid insecticides on muscle tissue transaminases of Oreochromis niloticus in vivo

Organophosphates and synthetic pyrethroid insecticides have been commonly used in public health and agriculture. The present study aimed to evaluate the sub-lethal effects of organophosphates and synthetic pyrethroid insecticides on transaminases: glutamate oxaloacetate/aspartate transaminase (AST) and glutamate pyruvate/alanine transaminase (ALT) in Oreochromis niloticus. Fish were exposed to malathion (OP), chlorpyrifos (OP) and λ-cyhalothrin (synthetic pyrethroid) at sub-lethal concentrations of 1.425, 0.125 and 0.0039 ppm, respectively for 24 and 48 h. AST and ALT activities were shown to be remarkably (p < 0.05) decreased and increased, respectively in O. niloticus treated with the insecticides. The highest and lowest inhibition in AST level were noted as -12.2% and -12.2% in chlorpyrifos and λ-cyhalothrin 24 h treated fish samples, respectively. The highest and lowest elevation in ALT level were recorded as + 313% and 237% in 48 h chlorpyrifos and 24 h malathion treated fish samples, respectively. This indicates that the insecticides used in this study did not result in death but in changes in AST and ALT enzyme activities. Therefore, organophosphates (malathion, chlorpyrifos) and synthetic pyrethroid (λ-cyhalothrin) insecticides are toxic to fishes and could affects their survival in their natural habitat.

Heavy metal and pesticide levels in dairy products: Evaluation of human health risk

Cattle milk's health benefits can be compromised by the presence of contaminants. The levels of cadmium, copper, lead and zinc, and residues of dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), dichlorodiphenyltrichloroethane (DDT) were determined in soil, milk and cheese samples collected from cow farms from 3 Romanian areas with industrial and agriculture tradition. A new methodology was applied for the determination of the corrected estimated daily intake (cEDI) corresponding to the aggregate dietary exposure. For the risk assessment, we calculated the source hazard quotient (HQs) for each contaminant and the adversity specific hazard index (HIA). Cadmium, copper, lead and zinc, and the sum of DDT levels in soil samples were below maximum residue levels (MRLs). The MRLs of lead and DDD were exceeded in milk and cheese samples from all the 3 areas. The MRLs of copper and zinc were exceeded in cheese samples from area 2 and 3. HQs >10 for lead indicates increased risk, while HQ > 1 for copper and sum of DDT indicates moderate risk for both milk and cheese. By calculating the HI_A, we identified a moderate and increase risk for nephrotoxicity, hepatotoxicity, hematotoxicity, cardiotoxicity and reproduction toxicity after consumption of the dairy products from the 3 areas.

Incidence, stability and risk assessment for sulfonamides and tetracyclines in aqua-cultured Nile Tilapia fish of Egypt

The current study was conducted to determine sulfonamides (SAs) and tetracyclines (TCs) residuals in farmed Nile Tilapia fish (Orechromis niloticus) using the solid phase extraction (SPE) technique and high performance liquid chromatography with diode array detection (HPLC-DAD). As well, to assess the potential health risk due to the consumption of contaminated fish following its household thermal processing. Tilapia samples were collected from four governorates in Egypt; El-Fayoum, Giza, Cairo, and Alexandria. The results showed that 56.3 % (27 out of 48 samples) of fish samples were free of antibiotics, while 10.4 % and 33.3 % of samples were contaminated by SAs and TCs, respectively. Besides, oxytetracycline (OTC) showed the highest detected concentrations ranged from 52.8 to 658.5 (μg/kg), followed by chlortetracycline (OTC) (35.89-109.76 μg/kg), and tetracycline (TC) (68.8-96.7 μg/kg). While the detected SAs were between 32.89 μg/kg (sulfamethazine: SMT) and 136.43 μg/kg (sulfadimethoxine: SDM). As well, sulfamethoxazole (SMX) showed an average concentration of 52.41 μg/kg. Notably, only 7 samples (out of 21 positive samples) had residual levels exceeded the permissible limits. The study also concluded that freezing fish at -18 °C for one week had no significant effect on the stability of SAs and TCs. As well, SAs showed more stability than TCs against the thermal processing for fish. Indeed, the stability of SAs and TCs antibiotics was arranged in a descending order, shown as follows: SMT > SDM > SMX > CTC > TC > OTC. Eventually, no potential risk to the Egyptian population was found from the consumption of the contaminated fish samples by SAs and TCs.