The rapid industrialization and urbanization of recent decades have raised significant concerns regarding environmental pollution, particularly in aquatic ecosystems. Contamination of water by toxic metals is an environmental concern, and hundreds of millions of people are being affected around the world (Mousavi et al., 2013; Ghorani-Azam et al., 2016; Luo et al., 2020). While heavy metals are naturally found in aquatic environments, their concentrations have increased dramatically due to human activities, including industrialization, mining, and agricultural practices (Kalay & Cauli, 2000; Abah et al., 2021). These metals enter aquatic ecosystems through industrial discharges, agricultural runoff, and mining waste, leading to long-term contamination of water bodies.

Fish, especially catfish, are a major dietary protein source for millions of people worldwide, accounting for approximately 16% of global animal protein intake and 6% of total protein consumption (FAO, 2010). They provide essential nutrients such as polyunsaturated fatty acids, vitamins, and minerals, which are necessary for human health and growth (Daviglus et al., 2002; Okoli et al., 2022).  In Nigeria, where fish is a primary source of protein for the population, ensuring that fish remain free from contaminants is crucial. With the rising consumption of fish, particularly due to concerns over red meat consumption, the contamination of fish by heavy metals presents significant health risks (Castro-Gonzalez & Mendez-Armentab, 2008). Given their position in the food chain, fish are particularly vulnerable to bioaccumulation of heavy metals, and their contamination is therefore a major public health concern. Heavy metal contamination in aquatic ecosystems has severe ecological and health implications (Amachundi et al., 2022; Olawale et al., 2022). These metals bioaccumulate in fish tissues, causing physiological damage and posing risks to human health. For example, cadmium and mercury are known to accumulate in the liver and kidneys of fish, leading to tissue damage, neurological disorders, and, in severe cases, death (Yarsan et al., 2013; Ezeonu et al., 2022). For humans, consuming fish contaminated with heavy metals can result in serious health issues, including cancer, liver damage, kidney failure, neurological damage, and cardiovascular diseases. Therefore, the contamination of fish, particularly catfish, which is highly valued for its size and nutritional content, is of great concern for both public health and ecological sustainability. In addition to their health impacts, heavy metals also disrupt aquatic ecosystems by reducing species diversity, altering food webs, and affecting water quality. Contamination in aquatic environments affects not only fish but also other organisms that rely on these water bodies for survival (Olawale et al., 2023). Furthermore, polluted water bodies can compromise agricultural productivity by contaminating irrigation sources and harming soil health, exacerbating food security issues (Habibu et al., 2023). The accumulation of heavy metals in aquatic ecosystems has far-reaching consequences, making it essential to monitor and mitigate pollution in these environments.

In Nigeria, heavy metal contamination in aquatic ecosystems has become an emerging concern, particularly in regions like Ebonyi State. Ebonyi is rich in natural water bodies, but it is also vulnerable to pollution from increasing anthropogenic activities such as mining, industrial discharges, and agricultural runoff. These activities have led to rising contamination levels in the state's numerous rivers, lakes, and ponds, which threatens both aquatic life and public health (Okoli et al., 2021). Ebonyi is home to a large fishing industry, with fish farming and wild fish harvesting being common practices. Catfish, a major species in the region’s fish farming sector, is particularly susceptible to contamination due to its bottom-feeding nature, which exposes it to higher concentrations of pollutants in the sediments. Despite the increasing body of research on water pollution and fish contamination, few studies have focused on comparing heavy metal contamination in fish from natural versus artificial water bodies, particularly in the context of Ebonyi State. While many studies have examined general water pollution, there is limited research on specific metal concentrations in catfish from various environments. This gap highlights the need for focused research on heavy metal contamination in local fish populations, particularly in artificial water bodies like fish ponds, and how these metals accumulate differently compared to natural water bodies such as rivers.

Catfish farming is a growing industry in Ebonyi State, and it could benefit from more robust environmental management policies. By identifying the primary sources of contamination and assessing the levels of pollutants in different water bodies, this study will contribute to the development of more effective policies that can safeguard both the environment and public health. Understanding the levels of contamination in both natural and artificial water bodies will provide valuable insights into the ecological and health impacts of heavy metal pollution. The contamination of fish, particularly catfish, by heavy metals in Ebonyi State is a growing concern for both ecological and public health reasons.

This study aims to fill a significant gap in the literature by comparing contamination levels in fish from natural versus artificial water bodies. By analyzing the concentration of heavy metals in different organs of catfish, the research seeks to assess the extent of contamination and its potential risks to human health through consumption. The findings will provide crucial data to inform policymakers and stakeholders in Ebonyi and Nigeria at large, enabling the development of strategies for reducing pollution, ensuring the safety of fish for consumption, and promoting sustainable fisheries management.

Materials and Method

Reagents/Chemicals Used For the Study

The following reagents of analytical grade were obtained from Merck, Germany, and used throughout the study:

• Hydrochloric Acid (HCl): Specific gravity = 1.18
• Trioxonitrate (V) Acid (HNO₃): Specific gravity = 1.18
• Lead(II) Trioxonitrate (Pb(NO₃)₂): Specific gravity = 4.53
• Cobalt(II) Trioxonitrate (Co(NO₃)₂): Specific gravity ≈ 2.49
• Cadmium(II) Sulfate (CdSO₄): Specific gravity ≈ 4.69
• Nickel(II) Sulfate (NiSO₄): Specific gravity ≈ 3.68
• Copper(II) Tetraoxosulfate (CuSO₄·5H₂O): Specific gravity = 2.28
• Iron(II) Tetraoxosulfate (FeSO₄·7H₂O): Specific gravity = 1.898
• Sodium Arsenate (Na₃AsO₄): Specific gravity ≈ 1.87

Equipment and Apparatuses Used For the Study

The heavy metals were analyzed using the Varian 220 Fast Sequential Atomic Absorption Spectrophotometer. Other materials included containers for transporting fish samples from the field to the laboratory, knives/scalpels for dissection, stopwatches, weighing balances, and standard volumetric flasks for solution preparation.

Study Area

The study was conducted across three distinct locations in Ebonyi State, Nigeria. The locations include:

Ndibe Beach: A natural water source located in Afikpo, Afikpo North Local Government Area, Ebonyi State. This location serves as the natural habitat for the fish species used in the study.

Pond 1: An artificial pond located at Uwana, Afikpo, Ebonyi State. This pond serves as an alternate water source for the sample species.

Pond 2: Another artificial pond located at the entrance gate of Presco Campus, Ebonyi State University. This site also provides samples for analysis.

Figure 1.             Map showing the sampling sites

Sampling Design

The fishes (three in number) were purchased from the fishermen who were pre informed at the location in Afikpo very early in the morning. This was done as soon as they were coming out from their fishing boats at about 7.00 – 7.30am in the morning. At the pond in Uwana Afikpo, the fish was also procured same day. In Abakaliki location, the catfish was also purchased from the pond where the owners/managers of the fish ponds removed the catfish with plastic buckets. Fish samples from each of the locations were collected inside plastic bag with little water inside it. They were labeled appropriately and transported alive to the laboratory on the same day where they were killed. Prior to treatment, the fish samples were measured and weighed and the length varied between 12.5cm to 20cm while the weight also varied between 1.74kg and 2.15kg.

Preparation of Stock Solutions

A stock solution is a solution of higher concentration and is prepared from a Lead trioxonitrate(V), Cobalt (II)trioxonitrate(V), Cadmium (II) sulphate, Nickel (II) sulphate, Copper (II) tetraoxosulphate (VI), Iron (II) tetraoxosulphate (VI) and Arsenic trioxonitrate (VI). In preparing a stock solution for the analysis, specific mass of each of the salts of the metals was weighed. These salts were of high purity and were dissolved in 1 litre standard flask with deionized water and acidified with concentrated HNO3.  The resulting stock solution was made up to the mark with distilled water, stored in a brown-coloured polythene container. From this stock solution, series of working standards were prepared using serial dilution formula provided below:C1VI = C2V2.

Sample Preparation and Treatment/ Digestion 

The fish samples were dissected at the laboratory. All fish were washed with de-ionized water and laid out 1 h before dissection. The fish samples were placed on dissection board and excised with a scalpel to remove the organs-gills and liver. The muscle was also isolated. These were labeled according to locations. Exactly 2g of each sample (gills, livers and muscle) were weighed out and put in a small conical flask. Then 20 mL of aqua-regia (previously prepared) was added to the flask contained the sample. The flasks containing the samples were placed on a hot plate in a heating chamber and heated for about 20 minutes. At this point the samples have dissolved completely. They were removed from the plate and allowed to cool. After cooling, 30mL of water was added, and then filtered into aspiration plastic bottles and aspirated into the AAS for analysis

Sample Analysis Using Atomic Absorption Spectroscopy

Standard solutions were prepared from the stock solution of each heavy metal. The absorbancies of these solutions were also measured using the Varian 220 Fast Sequential flame atomic absorption spectrophotometer. Each sample was aspirated into the nebulizer through a capillary tube where the samples were converted into a fine mist of aerosol. Then, the aspirated sample in aerosol form enters the atomizer. For each metal, the concentration was determined from each linear calibration curve respectively. All standard solutions for specific metal were prepared immediately before analysis to avoid adsorption of metals on the containers and decomposition. The same instrumental conditions were used to run the standard solutions that were used for the samples for each metal. When the absorbance of a sample exceeds that of the highest concentration of the standard solution of a particular metal, appropriate dilution was made to bring the sample concentration within the linear response range.

Results

Heavy metal concentration in fish samples Collected from Ndibe beach and artificial ponds.

In this study, results of the analysis are presented in in the tables and figures shown below. Table 1 shows the location of sampling, the length and mass of catfish used for the study and the parts used. Based on the Table 1, catfish from river was of higher length and mass compared to those from the artificial ponds. The same parts of the catfish from both natural and artificial sources were used, gills, livers and muscles. The study also made use of 2 cm mass of the catfish samples for digestion prior for heavy metal concentration determination. The concentrations of the heavy metals (Pb, Cu, Ni, Fe, Co, Cd and As) in the fishes both from natural water (Ndibe Beach in Afikpo) and artificial water or ponds in Afikpo and (Abakaliki) are presented in Table 2 below.

Table 1. Data for length, mass and parts of Catfish used for analysis

Table 2. Concentration of heavy metals (Mg/L) in the gill, liver and muscle of fish sourced from natural and artificial water

This analysis focuses on the heavy metal content (lead [Pb], copper [Cu], nickel [Ni], iron [Fe], cobalt [Co], cadmium [Cd], and arsenic [As]) in fish samples (gills, muscle, and liver) collected from three distinct locations of Ndibe beach, Pond 1 around Ndibe beach and Pond 2 around Presco Campus of Ebonyi State University, Abakaliki. The data are compared to the World Health Organization (WHO) permissible limits for each metal to assess potential environmental and health impacts. In Ndibe beach (river) the concentration of Lead (Pb) content in the gill, muscle and liver of the fish was 2.943 ± 0.002, 3.251 ± 0.001 and 2.643 ± 0.002Mg/L respectively. The concentration of lead in the gill, muscle and liver of the fish harvested from pond 1 are 2.947 ± 0.001, 2.484 ± 0.003 and 2.305 ± 0.004 mg/L respectively. Similarly, the concentration of lead in the gill, muscle and liver of the fish from pond 2 was 2.950 ± 0.001, 2.904 ± 0.001 and 2.445 ± 0.003 mg/L respectively. All samples from the three sites show lead levels exceeding the WHO permissible limit of 0.01 mg/L significantly. The muscle samples from the River site exhibit the highest Pb concentration, indicating potential contamination, likely from industrial effluents or urban runoff into the river.

The concentration of copper in the gill, muscle and liver of the fish harvested from the river were 0.121 ± 0.00, 0.202 ± 0.001 and 1.336 ± 0.003 Mg/L respectively while in pond 1,  the concentration of copper in the gill, muscle and liver was   0.370 ± 0.002,  0.330 ± 0.001 and  0.679 ± 0.002 Mg/L respectively. In pond 2, the concentration of copper was  0.614 ± 0.003, 0.241 ± 0.003 and 0.561 ± 0.001 mg/L respectively. The mean copper concentrations in liver samples from the River site was 1.336 mg/L which was  notably higher than the WHO limit of 0.02 mg/L, even though other samples also exceeded permissible limits but not as in Cu. This suggests bioaccumulation and potential toxicity, particularly in the liver, indicating a need for further investigation into sources of copper pollution in the river site.

The concentration of nickel in the gill, muscle and liver of the fish harvested from the river were 0.004 ± 0.00, 0.023 ± 0.001 and 0.107 ± 0.001mg/L respectively. In pond 1, the concentration of nickel in the gills, muscle and liver were 0.588 ± 0.11, 0.011 ± 0.002 and 0.047 ± 0.001Mg/L respectively. In pond 2, the concentration of nickel in the gills, muscle and liver of the harvested catfish was  0.536 ± 0.003,  0.022 ± 0.002 and 0.061 ± 0.00 mg/L respectively. The nickel levels in gill samples from Pond 1 and Pond 2 significantly exceed the WHO limit of 0.02 mg/L, while other samples are below the threshold. The higher levels in gills may indicate higher exposure and bioavailability in pond environments.

The concentration of iron in the gill, muscle and liver of the fish harvested from the river was 2.066 ± 0.002, 2.634 ± 0.003 and 4.003 ± 0.002 Mg/L respectively whereas in pond 1, concentration of iron in the gill, muscle and liver of the fish were 3.382 ± 0.002, 3.519 ± 0.001 and 6.957 ± 0.002 mg/L respectively. In pond 2, the concentration of iron in the gill, muscle and liver of the harvested fish was 3.415 ± 0.004, 3.11 ± 0.00 and 5.811 ± 0.001 mg/L respectively.

Iron concentrations are above the WHO limit of 0.30 mg/L across all samples, particularly in liver samples. While iron is essential for organisms, excessive levels can indicate pollution and could pose health risks.

The concentration of cobalt in the gill, muscle and liver of the fish harvested from the river was 0.105 ± 0.002, 0.087 ± 0.001 and 0.244 ± 0.002 mg/L respectively. In pond 1, the concentration of cobalt in the gills, muscle and liver of the catfish was 0.022 ± 0.002, 0.017 ± 0.002 and 0.144 ± 0.002 mg/L respectively. In pond 2, the concentration of cobalt in the gills, muscle and liver of the fish was  0.031 ± 0.002, 0.007 ± 0.002 and 0.166 ± 0.001 mg/L respectively. Cobalt levels are below the WHO limit of 0.5 mg/L, indicating a relatively lower risk of toxicity. However, the higher concentrations in river samples suggest potential localized contamination sources for the river water.

The concentration of cadmium in the gill, muscle and liver of the fish harvested from the river was 0.431 ± 0.001, 0.042 ± 0.001 and 0.551 ± 0.001 mg/L respectively while in pond 1, the concentration in the gill, muscle and liver  was  0.242 ± 0.002, 0.121 ± 0.699, 0.421 ± 0.001 mg/L respectively. In pond 2, the concentration of cadmium in the gill, muscle and liver was 0.261 ± 0.001, 0.152 ± 0.001 and 0.492 ± 0.001mg/L respectively. Cadmium levels are alarmingly high in all samples, surpassing the WHO limit of 0.05 mg/L, particularly in the liver samples from the River. This poses significant health risks, emphasizing the need for urgent monitoring and remediation. The concentration of arsenic in the gill, muscle and liver of the fish harvested from the river was  0.03 ± 0.001, Nil and 0.002 ± 0.001 mg/L respectively. In pond 1,  the concentration of arsenic in the gills, muscle and liver was 0.001 ± 0.001, 0.001 ± 0.00 and 0.012 ± 0.002  mg/L respectively. In pond 2, the concentration of arsenic in the gill, muscle and liver of the harvested fish were 0.004 ± 0.001, 0.001 ± 0.00 and  0.005 ± 0.026 mg/L respectively. Arsenic concentrations are generally low across all sites, remaining below the WHO limit of 0.01 mg/L. However, even low levels can be harmful, warranting continuous monitoring for environmental safety.

Comparison of Metal Concentrations Across Study Locations

The concentrations of lead are relatively high across all locations, with liver samples showing the highest levels, particularly in the river (2.643±0.002 Mg/L) and Pond 1 (2.305±0.004 Mg/L) (Figure 2, 3 and 4). These levels were significantly above the WHO permissible limit of 0.01 Mg/L, indicating potential risks for both aquatic life and human consumers. The concentrations of copper vary widely, with the liver from the river showing the highest value (1.336±0.003 Mg/L). In all samples, Cu levels exceeded the WHO permissible limit of 0.02 Mg/L, suggesting possible environmental contamination, which could affect fish health and accumulate in the food chain. Generally, there is low concentration of copper across all samples, with the highest level recorded in the gill of fish from Pond 1 (0.588±0.11 Mg/L). However, all values are below the WHO limit of 0.02 Mg/L, indicating relatively lower risk from this metal. The iron levels are significantly higher compared to other metals, particularly in the liver and of fish from Pond 1 (6.957±0.002 Mg/L) and Pond 2 (5.811±0.001 Mg/L). While iron is an essential nutrient, excessive levels can be toxic to fish and indicate contamination.

Concentrations of cobalt are low across all samples, with the highest level being 0.244±0.002 mg/L in the liver of fish from the river. All values are below the WHO limit of 0.5 mg/L. Levels of cadmium are concerning, especially in the liver samples, with the river showing 0.551±0.001 mg/L, significantly exceeding the WHO limit of 0.05 mg/L. Cd is highly toxic and poses serious health risks. Arsenic was detected at low levels, with the highest concentration observed in the liver from Pond 1 (0.012±0.002 mg/L). While low, As can accumulate in tissues and is toxic, necessitating monitoring. 

Figure 2. Heavy Metal concentrations (mg/L) in gills of the sample (Catfish) from Afikpo River (Ndibe Beach) and Ponds in Afikpo and Abakaliki.

Figure 3. Heavy Metal concentrations (mg/L) in muscles of the sample (catfish) from Afikpo River (Ndibe Beach) and Ponds in Afikpo and AbakalikI.

Figure 4: Heavy Metal concentrations (mg/L) in Liver of the sample (catfish) from Afikpo River (Ndibe Beach) and Ponds in Afikpo and Abakaliki.

Discussion

The rapid industrialization and urbanization of recent decades have raised significant concerns regarding environmental pollution, particularly in aquatic ecosystems. Contamination of water by toxic metals is an environmental concern, and hundreds of millions of people are being affected around the world (Mousavi et al., 2013; Ghorani-Azam et al., 2016; Luo et al., 2020). While heavy metals are naturally found in aquatic environments, their concentrations have increased dramatically due to human activities, including industrialization, mining, and agricultural practices (Kalay & Cauli, 2000). This study carried out a comparative analysis of heavy metals content in the body and organs of cat fish samples in the Natural and Artificial Waters in Ebonyi State

Findings from the study revealed that concentrations of lead (Pb), copper (Cu), nickel (Ni), iron (Fe), cobalt (Co), cadmium (Cd), and arsenic (As) ranged from 2.305 to 3.251, 0.121 to 0.614, 0.004 to 0.588, 2.066 to 6.957, 0.042 to 0.492, 0.01 to 0.03 mg/L, respectively (Table 4.2). Elevated lead levels in fish pose significant risks to human health, exceeding the WHO limit (0.01 mg/L), indicating potential bioaccumulation. Copper levels in liver samples were as high as 1.336 mg/L, well above the safe consumption limit of 0.05 mg/L, suggesting serious pollution. Nickel concentrations, while low, could still affect fish growth and reproduction. Excessive iron can disrupt physiological functions, with liver concentrations up to 6.957 mg/L indicating potential environmental imbalance. Cobalt, though less monitored, can harm aquatic ecosystems at high levels and should be tracked. Cadmium levels, particularly in liver tissues (up to 0.551 mg/L), exceed the WHO limit (0.05 mg/L) and pose significant health risks. Arsenic was not detected in significant amounts, but its accumulation in fish warrants ongoing monitoring.

Heavy Metals Concentrations in the Organs and Muscle of Catfish in River and Ponds

Heavy metal concentrations were higher in the gills and livers of fish from both rivers and ponds compared to muscles, with few exceptions. In the river, the order of metal concentration in gills was Pb > Fe > Cu > Co > Cd > Ni > As, while Pond 1 had Fe > Pb > Ni > Cu > Cd > Co > As, and Pond 2 had Fe > Pb > Cu > Ni > Cd > Co > As.

Lead (Pb) concentrations reached 2.943 mg/L, exceeding the WHO limit of 0.01 mg/L. Copper was 0.121 mg/L, above the 0.02 mg/L limit. Nickel (0.004 mg/L) and iron (2.066 mg/L) were below the permissible limits. Cadmium and arsenic concentrations were 0.431 mg/L and 0.03 mg/L, respectively, with cadmium exceeding the permissible limit while arsenic was below it.

In Pond 1, Pb concentration was 2.947 mg/L, higher than in the river, and above the WHO limit. Copper and nickel concentrations (0.37 mg/L and 0.588 mg/L) were also above the permissible limit. Iron (3.382 mg/L) was higher than the river's value, while cobalt (0.022 mg/L) was lower. Cadmium (0.242 mg/L) exceeded the permissible limit, but arsenic (0.001 mg/L) was below it.

For Pond 2, Pb concentration was 2.95 mg/L, and copper was 0.614 mg/L, both above river concentrations. Nickel (0.536 mg/L) exceeded the permissible limit, while iron (3.415 mg/L) was below the maximum permissible limit. Cobalt and cadmium also exceeded permissible levels, but arsenic remained below the limit.

In the muscle of catfish from the river, lead (2.484 mg/L) and iron (3.519 mg/L) had the highest concentrations, exceeding permissible limits. Copper, cobalt, and nickel were slightly above the limits, while cadmium and arsenic were below.

The liver concentrations from Pond 1 showed Pb at 2.947 mg/L, higher than in the river, with copper (0.37 mg/L), nickel (0.588 mg/L), and iron (3.382 mg/L) above the river's concentrations. Cobalt, cadmium, and arsenic were

higher in the river than in Pond 1. In Pond 2, iron (3.415 mg/L) had the highest concentration, followed by lead (2.95 mg/L). Lead, copper, nickel, and cadmium exceeded permissible limits, while iron, cobalt, and arsenic were below them. These findings highlight that heavy metals concentrate more in the liver than other organs.

Comparative Analysis of Heavy Metals in the Fish Samples From River and Ponds

Fish from the ponds (artificial water) accumulated more heavy metals than those from the river (natural water), with iron (Fe) having the highest concentrations: 3.415 mg/L in Pond 2, 3.382 mg/L in Pond 1, and 2.634 mg/L in the river. The range for iron concentration in this study was 2.066-6.957 mg/L, which is below the recommended 30 mg/L. While iron is essential for oxygen transport in the body, excessive amounts can lead to liver cancer and diabetes.

Lead (Pb) and copper (Cu) followed iron in accumulation, with Pb concentrations of 2.943 mg/L in the river and 2.950 mg/L in the pond. Previous studies, like Madu et al. (2017), reported similar ranges of 2.61-5.07 mg/L from River Niger, confirming high lead levels that exceed the WHO permissible limit of 0.3 mg/L. Lead is toxic, causing neurotoxicity and nephrotoxicity (Mendez et al., 2010). Copper concentrations ranged from 0.12 to 1.33 mg/L, higher than the WHO limit of 1 mg/L, and similar to findings by Ekere et al. (2018). Copper excess can cause headaches, nausea, and liver and kidney damage.

Nickel (Ni) concentrations (0.004-0.588 mg/L) were below the permissible limit (0.600 mg/L), confirming safe levels. However, excess nickel can lead to hypoglycemia, asthma, and cancer (Oti et al., 2016). Cobalt (Co) concentrations were above the permissible limit of 0.050 mg/L in river samples but below the limit in pond samples.

Cadmium (Cd) concentrations ranged from 0.042 to 0.551 mg/L, higher than the permissible limit of 0.001 mg/L (WHO, 2015). While concentrations were higher in fish from the river, cadmium was more concentrated in liver tissues. Excessive cadmium intake can cause respiratory issues, kidney damage, and cancer (Codt et al., 2006).

Arsenic (As) levels ranged from 0.001 to 0.021 mg/L, below the 0.2 mg/L limit, but prolonged exposure can lead to cancer and other health problems (Tchounwou et al., 2003). The variation in heavy metal concentrations across the organs was statistically significant (p<0.05).

The analysis of heavy metal concentrations in fish harvested from water samples from various locations revealed concerning levels, particularly when compared to the World Health Organization (WHO) permissible limits. As more industrial activities, population as well as transportation increases, heavy metals increase in its accumulation in the water bodies and hence in the fish.

The concentration of heavy metals in the fish organs especially the gills and livers overshot the permissible limits. The fish in the ponds (artificial waters) tend to accumulate more heavy metals in their organs than those in natural waters. This may be due to source of the food for the fish and other production processes.

The data collected from three distinct locations, River, Pond 1, and Pond 2—are summarized as follows: The concentration of lead (mg/L) in fish obtained from river and different parts are gill (2.943), Muscle (3.251), Liver (2.643), in pond 1 Gill (2.947), Muscle (2.484), Liver (2.305) and in pond 2 Gill (2.950), Muscle (2.904), Liver (2.445). All sampled tissues across all locations exceeded the WHO permissible limit of 0.01 mg/L, indicating significant contamination.

The copper concentration (mg/L) as determined from different organs of the fish at different locations are; river; Gill (0.121), Muscle (0.202), Liver (1.336); pond 1; Gill (0.370), Muscle (0.330), Liver (0.679); pond 2; Gill (0.614), Muscle (0.241), Liver (0.561). The Cu levels were above the WHO limit of 0.02 mg/L in all liver samples and most gill samples, especially in the River and Pond 2. The analysis indicated significant contamination of heavy metals in the studied water bodies, with most concentrations exceeding the WHO permissible limits. This poses potential health risks to aquatic life and humans relying on these water sources.

Conclusion

This study aimed to evaluate the concentration of heavy metals in the body and organs of catfish samples collected from both the Afikpo River and fish farms in Afikpo and Abakaliki. The findings reveal notable differences in heavy metal concentrations across the sampled locations, indicating the potential environmental impact of these water bodies on aquatic life.

The results demonstrated that catfish from the Afikpo River exhibited elevated levels of lead (Pb), copper (Cu), cobalt (Co), cadmium (Cd), and arsenic (As) compared to those from fish ponds except for iron. Specifically, the gills, muscles, and livers of catfish from the river contained concentrations of heavy metals that often exceeded the permissible limits set by the World Health Organization (WHO), particularly for Pb and Fe. For instance, the liver samples from the river indicated significant lead concentrations (2.643 ± 0.002 Mg/L), highlighting a potential risk for both the fish and the consumers.

The comparative analysis between the river and pond samples revealed that the catfish from the river has higher concentrations of several heavy metals, particularly lead and cadmium, suggesting that the natural water source may be contaminated. In contrast, the fish farm samples exhibited lower levels of these metals, likely due to controlled feeding and water management practices.

The elevated concentrations of heavy metals in catfish from the Afikpo River pose significant health risks to consumers and indicate environmental pollution. The presence of these contaminants in fish from both natural and controlled environments underscores the need for continuous monitoring and assessment of water quality, as well as public awareness regarding potential health risks associated with fish consumption.

This study highlights critical environmental and public health concerns regarding heavy metal accumulation in aquatic organisms, necessitating immediate action to mitigate pollution and ensure food safety in the affected regions.

There should be continuous monitoring of the level of environmental pollutants especially industries and activities that impact on the waters. This is to ensure that fish and equally the water is not contaminated above permissible level.

The source of feed for fish farmers, water and other fish farming production processes should also be monitored to ensure safety of fish consumers.

Minimum standards should be set for entrants into the business of fish farming both in qualification and facility to ensure knowledge of safety of products and processes. Further research is warranted to explore the sources of contamination and to develop strategies for effective management of water bodies to protect both aquatic ecosystems and human health.

Acknowledgments

We want to thank all the researchers who contributed to the success of this research work.

Funding

No funding was received for this research work.

Conflicts of Interest

The authors declared that there are no conflicts of interest.