Assessing water quality is necessary to ascertain its viability for domestic, industrial, and agricultural purposes. A total of 48 water samples were, respectively, drawn from the Rivers Karawa and Iyiaji located in Ezeagu and Uzo-uwani which are typical rural areas in Enugu State, Nigeria. These samples were taken in two seasons (early rainy season and late dry season). Physicochemical properties were determined using standard methods. The scaling and corrosivity potentials of the water were evaluated using the Larson-Skold index, aggressive index, Puckorius scaling index, and Ryznar stability index models. Additionally, seven irrigation evaluation criteria, as well as spatial distribution maps, were used to determine the suitability of the river waters for irrigation purposes and to interpolate the spatial distribution of the river water quality parameters. Major ion chemistry was used in the assessments. The physicochemical properties of river waters fell within the recommended standard values. However, NO₃⁻ greatly exceeded the recommended range in both rivers. The cations and anions from River Karawa were Ca²⁺ > Mg²⁺ > K⁺ > Na⁺ and NO₃⁻ > Cl⁻ > SO₄²⁻ > HCO₃⁻ > CO₃⁻ > PO₄⁻, while those from River Iyiaji were Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and Cl⁻ > SO₄²⁻ >NO₃⁻ > PO₄⁻ > HCO₃⁻ > CO₃⁻. A piper plot showed the predominance of Ca²⁺ and Mg⁺, as well as SO₄²⁻ and Cl⁻, in both rivers. The seven irrigation assessment indices indicated that the water of the Rivers Karawa and Iyiaji is suitable for irrigation purposes. In addition, the scaling and corrosivity models predicted that the river waters have high scaling and corrosivity potentials. Specifically, while the aggressive index suggested that it is severely corrosive, the Langelier saturation index suggested that the water from both rivers is supersaturated and, thus, has potential to scale.

The physico-chemical and microbial analyses of fifteen hand-dug wells (HDWs) and six boreholes (BHs) in the Ezeagu and Uzo-uwani Local Governments Areas (LGAs) of Enugu State in south-eastern Niger...

The unmodified and modified Irvingia gabonensis (IG) were characterized with Fourier transform infrared (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric analyzer (TGA), and scanning electron microscope (SEM). The experimental conditions revealed the optimum adsorption efficiency was achieved at pH 6 within 30 min. FTIR spectra showed an observable shift in peaks attributed to the pretreatment with NaOH that necessitated the breakdown of the organic compounds. It was established from the SEM image under different magnifications that the surface morphology of the biosorbent consists of heterogeneous layers and pore cavities which acted as potential sites for Pb2+ adsorption. However, there was a considerable increase in the BET surface area, pore size, and pore width on the modified biosorbent compared to the unmodified biosorbent though this did not translate into higher adsorption capacity. The experimental data were best fitted with the Temkim isotherm model suggesting heterogeneous uptake of Pb2+ onto the base-modified Irvingia gabonensis seed husk. The maximum adsorption capacity was 2.58 mg/g and the kinetic model is best described with the pseudo-second-order reaction suggesting a chemical adsorption mechanism. The two error functions (HYBRID and MPSD) suggested the pseudo-second-order reaction mechanism in the adsorption of Pb2+ onto the base-modified Irvingia gabonensis.

Organochlorines (OCP) and organophosphates (OPP) are synthetic agricultural pesticides utilized in pest control. Its residues are found within food matrixes long after application, and at a certain amount, it is considered significantly toxic upon consumption. Their concentrations in two species of freshly harvested Vigna unguiculata were examined. A mixture of hexane and acetone was used as extracting solvent, while identification and quantification, after sample clean-up, were executed using a gas chromatography–electron capture detector (GC–ECD). Health risk associated with the consumption of the beans was assessed using hazard index and hazard quotient. Carcinogenic and non-carcinogenic health risks amongst consumers of Vigna unguiculata from study area were also determined. Eleven organochlorine pesticides (OCP) and seven organophosphate pesticide (OPP) residues were ascertained in white species, while twelve OCPs and seven OPPs were found in brown species. The results revealed mean OCP and OPP concentrations in white species to range from 0.0067 ± 0.0012 to 0.661 ± 0.403 mg/kg and 0.006 ± 0.001 to 3.000 ± 2.413 mg/kg, respectively. In brown species, OCP mean concentration levels were within 0.010 ± 0.006–0.527 ± 0.336 mg/kg, while OPPs were within 0.068 ± 0.007–1.195 ± 0.150 mg/kg. Four OPP residues were above maximum residue levels (MRL) in both species. Five OCPs in white beans and six OCP residues in brown beans were above the recommended MRLs, respectively. The health risk index (HRI) and hazard quotient (HQ) recorded were greater than one (> 1) for Dieldrin residue in brown beans, indicating the likelihood of Dieldrin to cause toxic health issues. Hazard index for total OCP and OPP burden in white (1.838) and brown (2.515) beans was also > 1. With the exceptions in 4,4-DDE in brown, and p,p’-DDD in both species, other residues recorded cancer risk (CR) values > 10^–6 suggesting a probable carcinogenic health risk from consumption of both Vigna unguiculata species. The correlation analysis indicated no significant difference between the concentration of pesticides in the brown and white Vigna unguiculata which implies that concentration of pesticides in one does not affect the concentration in the other species. It could be seen that the practice of using banned pesticides for agricultural purposes is still obtained in Nigeria. It is therefore recommended that the regulatory agencies saddled with the responsibility of enforcing the ban should live up to expectation. Graphical abstract