Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental contaminants that present several environmental risks including human health. The 16 priority PAHs including its 1-methylnaphthalene, and 2-methylnaphthalene were determined in sediment and fish samples (Clarias anguillaris and Oreochromis niloticus) of River Owan, Edo State, Nigeria using gas chromatography (GC) equipped with flame ionization detector (FID) and other standard laboratory protocols. The isomeric ratio was used for source diagnosis, sediment quality guidelines, and risk models of incremental lifetime cancer were used for risk assessment. 1-methylnaphthalene and 2-methylnaphthalene were most predominant in all sediment samples analysed. The ∑LMW PAHs ranged between 0.093—0.250 μg/kg; ∑HMW PAHs were 0.107—0.579 μg/kg. The sediment samples range for ∑PAHs was 0.280–0.810 μg/kg with concentration order of increase: SE5>SE4>SE3>SE6>SE1>SE2>SE7 for the seven sampling locations. The ∑PAHs for Oreochromis niloticus was 0.190 μg/kg, which is higher than the value of Clarias anguillaris 0.080 μg/kg, and these values were greatly lesser when compared to the European Commission limit of 12.00 μg/kg. The diagnostic ratio indicates that the sources are more pyrogenic than petrogenic, revealing combustion from grass, wood, and bush burning. Sediment quality assessment showed that the ∑PAHs were lower than the regulatory values of sediment quality guidelines (SQG) assessment suggesting no ecotoxicological effects on the benthic organisms in this area at present. The Incremental Life Cancer Risk results were in the range of 9.15 × 10⁻¹²—1.46 × 10⁻⁶ for children, and 7.78 × 10⁻¹²—1.76 × 10⁻⁶ for adults considering the three routes of exposure. The incremental life cancer risk assessment showed a negligible risk.

Air quality has been a major concern throughout the world, Nigeria inclusive. The monitoring of air quality involves indoor and outdoor air quality. In this study, our concern was on indoor air quality. The aim of this study was to assess the air quality of residential homes (17), classrooms (3), hospitals (2), offices (5), Shops (2), and laboratories (5) in Akure, Nigeria in terms of formaldehyde (HCHO), total volatile organic compound (TVOC), Particulate matter (PM1.0; PM2.5, and PM10). A Multifunction Air Detector was used for the assessment using the manufacturers’ procedures and the locations were identified using a Mini GPS. The results revealed as follows: HCHO (0.001-0.030 mg/m3), TVOC (0.003-362 mg/m3), PM1.0 (004-014 µg/m3), PM2.5 (006-020 µg/m3), and PM10 (006-022 µg/m3). The results obtained were below the 24 h pollution recommended standards (0.1 mg/m3- HCHO; TVOC; 10-20 μ/m3 PM) of EPA and WHO. Statistically, there were correlations within the pollutants and weather. The Indoor air quality (IAQ) depicted the areas as ‘good,’ and toxicity potential (TP) were below unity. Although the locations looked safe, it is recommended that constant monitoring of the indoors should be ensured and proper ventilation should be provided.

The study of water quality is crucial given the amount of industrial, agricultural, and other human activities at the sampling sites. The aim of the study was to assess the physicochemical characteristics and selected contamination patterns of water samples in Nigeria. This study used conventional analytical techniques to analyze the physicochemical parameters in water samples from 33 sampling sites (dug wells, boreholes, rivers, and rainwater) in three different states (Ekiti, Osun, and Ondo) of Nigeria. These parameters included pH, total dissolved solids (TDS), electrical conductivity (EC), temperature, relative humidity (RH), and four elemental parameters (Ca, Na, Fe, and Cu). The enrichment factor (EF), contamination factor (CF), and metal index (MI) were used to characterize the data. Temperature (28.17 °C), TDS (130.2 mg/L), EC (260.0 μS/cm), pH (6.88), Na (14.47 ppm), Ca (25.74 ppm), Fe (0.49 ppm), and Cu (0.08 ppm) were the average values from the results. Na and Ca had a direct relationship with one another. The levels of heavy metals were below those recommended by the Nigerian Industrial Standard for Drinking Water Quality (NISDQW) and the World Health Organization (WHO). The metal levels in the water samples were over 1.5, which is the threshold value indicated by the EF classifications. In particular, EFs were moderate to significantly enriched. All element CFs were below the Level 1 pollution threshold. The water samples are pure based on the MI’s rating of water quality. Human and natural activities may represent a risk to the local public health; hence, it is highly advisable that all stakeholders adopt rapid and long-lasting collective action to limit pollution levels as part of the water quality governance system.

Polycyclic aromatic hydrocarbons (PAHs) belong to the group of persistent organic pollutants (POPs), which are major environmental pollutants associated with the environment. In this study (preliminary), the concentrations of eighteen (18) PAHs in soil, sediment, and fish sample (Clarias anguillaris) of Owan River and agricultural soil samples around the river in Edo State were studied using standard analytical methods. Gas chromatograph equipped with flame ionization detector (GC-FID) was used for the determination of PAHs. The study revealed the presence of the 18 determined PAHs in the soil, sediment, and fish (Clarias anguillaris) samples in varying concentrations. The concentrations of PAHs in the soil samples ranged between 0.0000–0.0463 (µg/kg) with total concentrations of ∑0.2390 (µg/kg) for soil sample 1 and 0.0000–0.0506 (µg/kg) with total concentration of ∑0.2700 (µg/kg) for the soil sample from location 2. The concentrations of the PAHs components in the sediments samples ranged between 0.00332–0.0319 (µg/kg) with total concentration of ∑0.150592 (µg/kg) for the sediment sample 1 and 0.002092–0.05866 (µg/kg) with total concentration of ∑0.0312183 (µg/kg) for the sediment sample 2. The concentration of PAHs components in the fish sample ranged between 0.0000–0.0746 (µg/kg) with total concentration of ∑0.300 (µg/kg). The concentrations of PAHs were higher in the soil samples than in the sediment samples. Concentrations of the PAHs residues detected in the fish samples were higher than those in the soil and sediment samples. In furtherance of this study, the number of sampling stations shall be increase to cover other communities while data generated will be subjected to more ecological risk assessments.

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