The stability and conservation of the aquatic habitat, be it fresh water, brackish and marine waters are very vital for both the ecological stability and biotic diversity as a source of food for human population [1].  These aquatic environments are vulnerable to contamination by various pollutants, including polycyclic aromatic hydrocarbons (PAHs), which are a group of organic compounds with multiple fused aromatic rings. Polycyclic aromatic hydrocarbons (PAHs) are a class of concerning contaminants that can cause severe threat to human health and cause direct or indirect harm to aquatic organisms and ecosystems [2]. Organic compounds known as polycyclic aromatic hydrocarbons (PAHs) are made up of at least two fused benzene rings arranged in various ways which are produced as a result of carbon-based materials’ incomplete combustion [3]. As a result of their detrimental implications on the health of man, and the environment, which include their carcinogenicity, mutagenicity, teratogenicity, etc., sixteen (16) members of PAHs are documented to be priority contaminants according to the United States Environmental Protection Agency [4]. Polycyclic aromatic hydrocarbons (PAHs) have taken considerable attention due to their ecological danger, socioeconomic repercussions, and impact on human health [5]. The main anthropogenic sources of PAHs are industrial activities, combustion of fossil fuels and waste, automobile exhausts, and even natural sources, like forest fires and volcanic eruptions were reported by ATSDR [6] and Bostrom et al. [7].

Polycyclic aromatic hydrocarbons (PAHs) are often released into aquatic systems through industrial processes, urban runoff, and natural sources such as oil spills or spillage [8]. The physico-chemical properties of water, including temperature, pH, dissolved oxygen, salinity, and turbidity, play a crucial role in the distribution, behavior, and overall health of aquatic organisms. These parameters affect the solubility and bioavailability of pollutants like polycyclic aromatic hydrocarbons (PAHs), which in turn impact the health and survival of aquatic life [9]. Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic compounds that are resistant to degradation, leading to their persistence in aquatic ecosystems [10]. Fish and other aquatic organisms can accumulate polycyclic aromatic hydrocarbons (PAHs) through direct exposure via water or by consuming contaminated food items. Polycyclic aromatic hydrocarbons (PAHs) have been associated with a range of negative effects on aquatic life, including developmental abnormalities, reduced reproductive success, and increased susceptibility to diseases [11].  Due to their widespread use and release, polycyclic aromatic hydrocarbons can be found in various environmental compartments, including surface water and sediments of rivers [12]. Understanding the concentration of polycyclic aromatic hydrocarbons in surface water and sediments is crucial for assessing the environmental health of river ecosystems. Elevated levels of these compounds can have detrimental effects on aquatic life and human health, making it very essential to be monitored in order to manage their presence in our environment [13]. The PAH pollutants are ubiquitous and can be found equally in aquatic and terrestrial ecosystems, as well as in the atmosphere [14]. As from last decade, the pollution of water bodies by chemical toxicants has become a topic of public discourse and concern in many countries. Polycyclic aromatic hydrocarbons (PAHs) are carcinogens and being ubiquitous in nature, are daily being released into water bodies as a result of anthropogenic sources [15]. . Long-term exposure to low levels of some PAHs have caused cancer in laboratory animals. Benzo(a)pyrene is the most common PAH to cause cancer in animals. Studies of workers exposed to mixtures of PAHs and other compounds have noted an increased risk of skin, lung, bladder, and gastrointestinal cancers. The information provided by these studies is limited because the workers were exposed to other potential cancer-causing chemicals besides PAHs. Although animal studies have shown adverse reproductive and developmental effects from PAH exposure, these effects have generally not been seen in humans [16].

Fish is an integral part of aquatic ecosystems and can act as bio-indicators of water quality and environmental contamination. Studying their physicochemical properties and PAH concentrations can help assess the health of aquatic environments. Fish are a common food source for humans, and the presence of PAHs in fish can pose health challenges if consumed [17]. Understanding PAH concentrations in fish is crucial for assessing potential risks to human health. High PAH concentrations in fish can have detrimental effects on aquatic ecosystems. Studying these concentrations helps in understanding the impact on aquatic life and ecosystem health. Many regions have regulations and standards for the permissible levels of PAHs in fish for human consumption [18]. Studying PAH concentrations in fish in the River Niger can aid in identifying and tracking pollution sources, helping authorities to take corrective measures to reduce contamination [19, 20]. The rate of activities going on in the Odoekpe, Atani and Osamala stretch of the River Niger has reached a crescendo that warrant that a study on the safety of the water and bio-resources from it are safe for people living there. These activities includes; continuous sand dredging and tipping, discharge of industrial effluents by industries, washing of articulated tanker used in carrying petrol, chemicals, herbicides, insecticides and other agro-chemicals in farming along it and most importantly River Niger serving as a sink for more than 80% of water run off for Nigeria as a country. The volume of waste generated from the Onitsha market are dumped into the river, therefore aid in the pollution and by extension in the polycyclic aromatic hydrocarbon (PAHs).The Odoekpe- Osamala stretch of River Niger is densely populated..The aim of this research is to study the physico-chemical properties and polycyclic aromatic hydrocarbon concentrations of water and fish from River Niger, (Odoekpe,Atani and Osamala stretch).

Description of Study Area

The study was carried out in River Niger, at Odoekpe, Atani and Osamalla stretch of the River in Ogbaru Local Government Area of Anambra State, Nigeria. The data were collected from three different stations tagged as Station I (Odoekpe), Station II (Atani) and Station III(Osamala) as shown in Figure 3. The choice of these different stations was based on the level of activities going on there.

Sampling Station 1 (Odoekpe)

Odekpe is within the Latitude: 6°04'57.9"N and Longitude: 6°44'45.2''E. Odekpe has a tropical savanna climate. It is warm every month with both a wet and dry season. The average annual temperature for Odekpe is 32° degrees centigrade and there is about 834 mm of rain in a year. It is dry for 125 days a year with an average humidity of 76%.The majority of the local indigenes are involved in farming and fishing. Some of the anthropogenic activities that affects the River Niger in Odoekpe sampling station are the sand tipping and dredging, industrial effluents by industries that are situated along the river, the town market that is located at the bank of the River Niger as the market wastes are all thrown into the river, farming activities, washing of articulated oil tanker, artisanal fishing.

 Sampling Station 2 (Atani)

Atani is a city on the Eastern bank of the Niger River in Anambra State, Nigeria. Atani is the headquarter of Ogbaru Local Government Area of Anambra State. The wet season is warm, oppressive, and overcast and the dry season is hot, muggy, and partly cloudy in Atani.The geo coordinates are 6° 7' 17" N, and 6° 46' 10" E. Over the course of the year, the temperature typically varies from 67°F to 88°F and is rarely below 60°F or above 91°F.The temperature in Atani varies so little throughout the year that little can one differentiate hot and cold seasons. Some of the activities that goes on there are farming activities because the Atani people are known for rice,yam and cassava farming, fishing, sand dredging and tipping, washing of articulated oil tankers.

Sampling Station 3 (Ossomala)

Ossomala is a village in Anambra State, Nigeria.Ossomala is a traditional community, with a strong focus on agriculture and fishing. The people of Ossomala speak Igbo, and the village is known for its rich cultural heritage, including traditional dances and festivals. The people of Ossomala are also known for their hospitality, and the village is a popular destination for

Description of Study Area

The study was carried out in River Niger, at Odoekpe, Atani and Osamalla stretch of the River in Ogbaru Local Government Area of Anambra State, Nigeria. The data were collected from three different stations tagged as Station I (Odoekpe), Station II (Atani) and Station III(Osamala) as shown in Figure 3. The choice of these different stations was based on the level of activities going on there.

Sampling Station 1 (Odoekpe)

Odekpe is within the Latitude: 6°04'57.9"N and Longitude: 6°44'45.2''E. Odekpe has a tropical savanna climate. It is warm every month with both a wet and dry season. The average annual temperature for Odekpe is 32° degrees centigrade and there is about 834 mm of rain in a year. It is dry for 125 days a year with an average humidity of 76%.The majority of the local indigenes are involved in farming and fishing. Some of the anthropogenic activities that affects the River Niger in Odoekpe sampling station are the sand tipping and dredging, industrial effluents by industries that are situated along the river, the town market that is located at the bank of the River Niger as the market wastes are all thrown into the river, farming activities, washing of articulated oil tanker, artisanal fishing.

 Sampling Station 2 (Atani)

Atani is a city on the Eastern bank of the Niger River in Anambra State, Nigeria. Atani is the headquarter of Ogbaru Local Government Area of Anambra State. The wet season is warm, oppressive, and overcast and the dry season is hot, muggy, and partly cloudy in Atani.The geo coordinates are 6° 7' 17" N, and 6° 46' 10" E. Over the course of the year, the temperature typically varies from 67°F to 88°F and is rarely below 60°F or above 91°F.The temperature in Atani varies so little throughout the year that little can one differentiate hot and cold seasons. Some of the activities that goes on there are farming activities because the Atani people are known for rice,yam and cassava farming, fishing, sand dredging and tipping, washing of articulated oil tankers.

Sampling Station 3 (Ossomala)

Ossomala is a village in Anambra State, Nigeria.Ossomala is a traditional community, with a strong focus on agriculture and fishing. The people of Ossomala speak Igbo, and the village is known for its rich cultural heritage, including traditional dances and festivals. The people of Ossomala are also known for their hospitality, and the village is a popular destination for tourists who are interested in learning about traditional Nigerian culture.

The map of the study area showing the sampling points is presented in Figures 1, 2, 3.

tourists who are interested in learning about traditional Nigerian culture.

The map of the study area showing the sampling points is presented in Figures 1, 2, 3.

Figure 1: Map of Nigeria Showing States.

Figure 2: Map of Anambra State Showing River Niger.

                  Figure 3: Map Showing the Sampling Stations.

Sample Collection

All sample containers were aseptically washed thoroughly with detergents and thoroughly rinsed with distilled water. Water samples were collected downstream of the river. The samples were collected from three sample stations and the fish was taken in an ice-cooler box to the laboratory at Docchy analytical laboratories and all sample containers were aseptically washed thoroughly with detergents and thoroughly rinsed with distilled water. Water samples were collected downstream of the river. The samples were collected from three sample stations and the fish was taken in an ice-cooler box to the laboratory at Docchy analytical laboratories and environmental services limited Anambra state, Awka. The water samples were collected at the middle of the river with containers by dipping the sampler below the water surface to minimize the contamination of water sample by surface films and cocked below water surface to avoid air entrapment. The fish samples used was polypterus species (Anectus) which was purchased from fishermen at the bank of the river and put in the ice-cooler box and transported to the laboratory at  Docchy analytical laboratories and environmental services limited, Awka,  Anambra state.Some physicochemical parameters were determined in the water samples using appropriate digital readout meters in situ. These parameters include temperature, dissolved oxygen, BOD and total dissolved solids.

Fish Sample

Polypterus annectens, commonly known as the African bichir or Cuvier bichir, is a species of freshwater fish in the genus Polypterus. It is native to tropical Africa, where it inhabits rivers, lakes, and swamps. It can grow up to 45 cm (18 in) in length and has a distinctive appearance with 7 to 14 dark vertical bars on its body and numerous dorsal finlets.Polypterus annectens belongs to the family Polypteridae, which is one of the oldest groups of living fishes. They have retained some primitive features, such as lungs, ganoid scales, and lobed pectoral fins. They can breathe air through a spiracle on the top of their head, which allows them to survive in oxygen-poor waters. They are also able to move on land using their pectoral fins and body undulations.

Plate 1: Picture of Polypterus Annectus.

Polycyclic Aromatic Hydrocarbons Water Sample Analysis

This was analyzed according to AOAC [21].Gas chromatography (GC) HP7683 Series equipped with flame ionization detector (FID) was used for analysis of the PAHs. The extraction technique employed in this work was the United States’ Environmental Protection Agency (USEPA) Method 3510 for aqueous matrix for the analysis of semivolatile and non-volatile organics. After filtration, 100 ml portion of the water sample was transferred into a 2 L capacity glass-separating funnel. Then 30 ml of saturated sodium chloride (NaCl) was added to produce a salt out effect. It was thoroughly mixed by inverting the flask three to four times. 100 ml of Dichloromethane as extraction solvent was added and this was vigorously shaken manually for 2-3 minutes and releasing the pressure intermittently. The phases were then allowed to separate for 5 minutes and the Dichloromethane extract (organic layer) was separated or collected from the aqueous layer. The extraction was repeated with 100 ml of Dichloromethane and the organic layers were put together and dried over anhydrous magnesium sulphate. The extracts from water samples were then concentrated on rotary vacuum evaporator to about 2 ml and subjected to clean up.

Clean-Up of Extract (Purification Using Silica SPE Cartridge)

One gram of silica gel that previously had been activated at 130 ºC for 10 hours was carefully packed into 10 mL polypropylene cartridge column and 6 mL Dichloromethane was used to condition the cartridge. The concentrated extract was then loaded onto the column and 50 mL pear shape flask was placed under the column to collect the eluate. A 10 mL dichloromethane was used to elute the column afterwards, and the total filtrate collected concentrated to just dryness using the rotary evaporator set at 38ºC. The residue was re-dissolved in 1 mL methanol and transferred into a 2 mL standard vial prior to quantification by Gas Chromatography.

Gas Chromatographic Conditions for Pahs Determination

The final extracts were analyzed by Gas Chromatograph-Buck M910 scientific gas chromatography equipped with combiPal autosampler and Flame ionization detector that allowed the detection of contaminants even at trace level concentrations (in the lower μg/g and μg/kg range) from the matrix to which other detectors do not respond. The GC conditions used for the analysis were capillary column coated with VF-5 (30 m + 10 m EZ guard column x 0.25 mm internal diameter, 0.25 μm film thickness). The injector and detector temperature were set at 270 ºC and 300 ºC respectively. The oven temperature was programmed as follows: 70 ºC held for 2 min, ramp at 25 ºC/ min to 180 ºC, held for 1 min, and finally ramp at 5 ºC/ min to 300 ºC. Nitrogen was used as carrier gas at a flow rate of 1.0 mL/ min and detector make-up gas of 29 Ml min-1. The injection volume of the GC was 1.0 μL. The total run time for a sample was 31.4 min.

Quantification of PAH Residues

 The residue levels of PAHs were quantitatively determined using peak area. Measurement was carried out within the linear range of the detector. The peak areas whose retention times coincided with the standards were extrapolated on their corresponding calibration curves to obtain the concentration

Fish Polycyclic Aromatic Hydrocarbons Analysis

This was analyzed according to AOAC [22], 10 gram of sample was weighed and quantitatively transferred into a 500 ml. beaker. 6g sodium sulphate was added and extracted using 300ml n hexane. The filtrate was concentrated. 10 ml. of acetonitrile was added to the sample and place in a shaker for 2 minutes. An additional 10 ml. portion of acetonitrile was added, and the separating funnel closed tightly and placed on a horizontal shaker. It was then set to shake continuously for 30 minutes at 300 rpm/min. and finally allowed to stand for 5 minutes to sufficiently separate the phases. 10 ml. of the supernatant was carefully taken and dried over 2 gm anhydrous magnesium sulphate through filter paper into 50 ml round bottom flask. This was then concentrated to about 1ml using the rotary evaporator, and made ready for silica clean up step.

Clean-Up of Extract (Purification Using Silica SPE Cartridge)

1ml of filtered residue was dissolved in 50ml of chloroform and transferred to a 100ml volumetric flask and which was diluted to the mark. Most of the chloroform were diluted at room temperature. Next, 1 ml of the reagent {20 vol% benzene and 55 vol% methanol) was added. It was sealed and heat it at 400c water bath for 10 minutes. After heating, the organic sample was extracted with hexane and water, so that the final mixture of the reagent, hexane and water, is in proportion of 1:1:1 (i.e., add 1ml each of hexane and water to the reaction mixture). The mixture was vigorously shaken by hand for 2min and emulsion broken by centrifugation. Half of the top hexane phase were transferred to a small test tube for injection.

Gas Chromatographic Conditions For PAH Determination

 The final extracts were analyzed by Gas Chromatograph-Buck M910 scientific gas chromatography equipped with Flame ionization detector that allowed the detection of contaminants even at trace level concentrations (in the lower μg/kg range) from the matrix to which other detectors do not respond. The GC conditions used for the analysis was capillary column coated with VF-5 (30 m + 10 m EZ guard column x 0.25 mm internal diameter, 0.25 μm film thickness). The injector and detector temperature were set at 250 ºC and 280ºC respectively. The oven temperature was programmed as follows: 120 ºC held for 4 min, ramp at 10 ºC/ min to 180 ºC, held for 2 min, and finally ramp at 5 ºC/ min to 300 ºC. Helium was used as carrier gas at a flow rate of 1.0 mL/ min and detector make-up gas of 29 Ml min-1. The injection volume of the GC was 10.0 μL. The total run time for a sample was 43 min.

Quantification Of PAH Residues

 The residue levels of PAH were quantitatively determined by the external standard method using peak area. Measurement was carried out within the linear range of the detector. The peak areas whose retention times coincided with the standards were extrapolated on their corresponding calibration curves to obtain the concentration

Determination of Physicochemical Parameters

Water sample analysis: The water samples were analyzed for physicochemical parameters such as temperature, Total dissolved oxygen (TDS), transparency, phosphate, water current, conductivity, magnesium turbidity, dissolved oxygen (DO), depth, biological dissolved oxygen (BOD).were determined using standard methods described by APHA (2005)

Statistical Analysis

The data collected were subjected to one-way Analysis of Variance (ANOVA) at 0.05 level of significance. The mean, standard deviation and significant difference were analyzed using SPSS (version 25.0) windows software.

Physicochemical Parameters of River Niger from Odoekpe/Atani/Ossomala Stretch of River Niger

The result of the physicochemical parameters of river Niger is presented in table 1. The result revealed that the mean temperature (29.18±0.332 ºC), pH (7.04±0.038), BOD (turbidity (11.00±0.650 NTU), alkalinity (30.42±0.251), TDS (30.42±0.251 mg/L), conductivity (125.47±58.097 µs/cm), nitrate (7.00±0.020 mg/L), magnesium (3.86±0.102) and phosphate (0.47±0.015) these values were below the WHO recommended standard. However, the mean values of DO (20.32±0.156 mg/l), BOD (5.84±0.158), turbidity (11.07±1.129), and depth (6.80±0.548 m) were above the recommended standard by WHO. Figure 1, showed the physicochemical properties of the various sampling stations in River Niger.

The results of the overall mean concentration of polycyclic aromatic hydrocarbon in fish and water collected from the Odoekpe- Akwaukwu stretch of River Niger is presented in Table 2. The table showed that the Benzo(a)pyrene recorded the highest concentration (0.185) from the river followed by 1_2 Benzanthracene (0.051) while Benzo(b) flouranthene had the least (0.001). However, the components of PAH in both fish and water were found to be lower than the recommended limit by WHO.   In fish obtained from the river, Benzo(a)pyrene recorded the highest concentration (0.182) followed by Benzo(g_h_I)perylene (0.058) while Benzo(b)flouranthene had least (0.002). There was significant difference among the concentrations of the components of PAH recovered from the fish.

From the analysis of the water samples collected from river Niger, it was observed that Benzo(a)pyrene recorded the highest concentration (0.188) followed by 1_2 Benzanthracene (0.050) while Benzo(b)flouranthene had least (0.001). There was a significant difference among the concentrations of the components of PAH recovered from the water samples.  In addition, all the components of PAH in both fish and water were found to be lower than the recommended limit by WHO. The Polycyclic Aromatic Hydrocarbons (PAHs) in fish from different sampling stations in a stretch of River Niger are presented in Table 3. The results indicated that the values of PAHs were higher   in fish samples from station II when compared to other sampling stations. The same trend were observed in water samples, where PAHs in water from station II were slightly higher than other sampling stations (Table 4).

Table 1: Physicochemical Parameters of Water in a Stretch of River Niger.

Means within the same row with different superscripts are significantly different (P<0.05)

Table 2: Polycyclic Aromatic Hydrocarbon (PAH) In Fish and Water in a Stretch of River Niger.

Means within the same row with different superscripts are significantly different (P<0.05)

Table 3: Polycyclic Aromatic Hydrocarbon (PAH) In Fish from Different Sampling Stations in a Stretch of River Niger.

Means within the same row with different superscripts are significantly different (P<0.05)

Table 4: Polycyclic Aromatic Hydrocarbon (PAH) In Water from Different Sampling Stations in a Stretch of River Niger.

Means within the same row with different superscripts are significantly different (P<0.05)

The physico-chemical parameters of any water body play a vital role in the abiotic and biotic factors interactions and to a great extent the conservation, sustainability and mediation of the aquatic body. This research showed that there was no significant difference (p>0.05) in the physico-chemical parameters (Temperature , Dissolved oxygen DO, pH, Biological Oxygen demand (BOD), Conductivity, Nitrate (N), Magnesium (mg), Phosphate (P) were within the permissible limit of World Health Organization and Food and Agriculture Organization[24]. These results are not in total agreement with the results recorded by Arazu et al. [25] on the same stretch of the River Niger, who recorded higher values of physico-chemical parameters of water in these locations.  The variation in the physico-chemical parameters can be attributed to increased anthropogenic activities going on in the river, the cosmopolitan nature of the area in terms of urbanization, industrial growth and indiscriminate sand dredging and tipping that are currently ravaging the length and breadth of the River Niger [26]. This research also showed that the mean depth of the River Niger at Odoekpe/Atani/Ossomal stretch is 6.8 which is in contrast with 7.31m recorded by Arazu et al. [25]. This can be attributed to the yearly flooding experienced in the River Niger caused by opening of Cameroon dam. These significant changes recorded in physico-chemical parameters of the River Niger can be linked to climate change, consequences of global warming.

Polycyclic Aromatic Hydrocarbons (PAHs) are class of chemicals that occur naturally in coal,crude oil and gasoline. They result from the pyrosis of burning coal,oil,gas,wood, garbage and tobacco. PAHs can bind to or form small particles in the air; and high heat used in cooking meat and other food materials can form PAHs[27]. The results from this research showed that there are seven (7) types of hazardous PAHs found in both fish and water from the River Niger. This research recorded the presence of the following PAHs Acenapthylene, Fluoranthene, Phenanthrene, 1_2 Benzanthracene, Benzo(a) pyrene, Pyrene, Benzo(g_h_i) perylene and Benzo(b) fluoranthene with the mean concentrations of 0.019 ± 0.005 and 0.013 ± 0.001, 0.010 ± 0.004 and 0.0.008 ± 0.003, 0.041 ± 0.002 and 0.020 ± 0.004, 0.053 ± 0.003 and 0.050 ± 0.007, 0.182 ± 0.008 and 0.0188 ± 0.003, 0.007 ± 0.000 and 0.007 ± 0.000, 0.058 ± 0.002 and 0.006 ± 0.000 and 0.002 ± 0.000 and 0.001 ± 0.001 in fish and water respectively. All these were found to be below the permissible limit of 0.2ug/L except for Benzo(a) pyrene that was above the WHO [24] permissible limit of 0.1ug/L.Benson et al. [28] recorded the presence of the following PAHs Phenanthrene, anthracene, fluoranthene, Pyrene, Chrysene and Benzo(a) anthracene with the mean concentration range of 0.024— 0.2836ug/L in Ekpan Creek of Niger Delta. This result varies with the report of Ogbeide et al. [29]. It was observed that sources of PAHs pollution were from Pyrogenic origin, anthropogenic sources, sewage dumping, effluents discharges, sand dredging and tipping and crude oil pollution[30].

Also, Olayinka  et al [31] analyzed total PAHs concentration from south western Nigeria and recorded a mean concentration range of 11.2 and 341.5ug/L in water while Ismail et al.[32] analyzed total PAHs and found range varied from 720.46 to 857.65ug/L in surface water indicating polluted water while this research recorded PAHs mean range of 0.001 ± 0.001 — 0.188 ± 0.003ug/L and are with the WHO permissible limit of 0.2ug/L[33].

This research showed that Benzo(a) Pyrene was found to be above the WHO permissible limit as was shown on Table 2 in both fish and water in all the stations. It is a known fact that (PAHs) can contaminate water from various source. These sources includes; Urban runoff, water washing vehicle emissions, industrial wastes, asphalt tar containing products into the river as is the case at Odoekpe/Atani/Ossomala stretch of the River Niger; industries that produce or use coal, oil and other fossil fuels may release PAHs into water ways through waste water discharges, Agricultural runoff can introduce PAHs into water as is the case along the bank of River Niger at all the sampling stations, PAHs can accumulate in sediments over time and the sand dredging and tipping at Odoekpe/ Atani/ Ossomala stretch of the River Niger is besieged by dredging activities, which results in the resuspension of these PAHs laden sediments, releasing them into the water column. The elevated concentrations of Benzo(a)Pyrene in both fish and water samples from all the sampling stations, highlights it's significance.

The present study has shown that the aquatic ecosystem of the study area is contaminated with PAHs from petrogenic and pyrolytic (fossil fuel combustion) sources as revealed by the various source identification analysis. It showed that the river has high petrogenic PAHs input source, indicates that the PAHs pollutants in these sites were mainly due to emission from exhausts, burning of wastes and smoking. It can be concluded that PAHs pose a significant environmental concern due to their persistence and potential adverse effects on aquatic ecosystems. The presence of PAHs in water can result from various anthropogenic activities, such as industrial processes and urban runoff. Additionally, their hydrophobic nature makes them prone to accumulating in sediments, potentially leading to long-term contamination. This research recorded mean PAH concentration in both fish and water below the recommended limits set by the World Health Organization (WHO) except for Benzo(a) Pyrene is reassuring from a public health perspective. This implies that the little significance differences recorded in the sampling stations are within acceptable safety threshold and minimizing possible potential health risks associated with PAHs pollution in aquatic organisms, water and human users.Although that the recorded PAHs concentrations are below the WHO permissible limit except for Bap, is reassuring from the public health point of view. But it's important to consider the cumulative accumulation and long—term exposure and the potential synergistic interactions between PAH compounds. Therefore, continuous monitoring and surveillance is pertinent to assess trends overtime, in order to detect any emerging risk, especially in a dynamic river such as River Niger.

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