Janefrances Ngozi Ihedioha

This study evaluated the concentrations of polycyclic aromatic hydrocarbons (PAHs) in soil, water, and edible plants within cashew nut processing clusters in Enugu, Nigeria. Following liquid–liquid and solid–liquid extractions, the concentration of sixteen PAHs congeners were determined using gas chromatography coupled with a flame ionization detector (GC‐FID). To predict the potential sources of these PAHs, a diagnostic ratio guide was employed and principal component analysis was performed. Mutagenic equivalent concentration, human health risk assessment, and ecological risk assessment were performed. The identified PAHs had concentration range: 786.31–2589.46 µg/kg in soil, 33.78–5476.37 µg/L in water, and 561.47–3047.84 µg/kg in vegetables. Except for one location, the vegetables had higher levels of low molecular weight PAHs, while high molecular weight PAHs were more prevalent in the water. The results showed that the studied location has a fair amount of PAH pollution, mostly from pyrogenic sources though the source apportionment models predicted multi‐sources. The ecological risk assessment indicated acenaphthene to be the most contributing contaminant while the health risk evaluations indicated that consumers of water and vegetables from this area may have risk for non‐carcinogenic health problems. There were substantial mutagenic equivalent quantities, and BaP metabolites were probably responsible. The study reveals that inefficient burning of biomass and fossil fuels has resulted in significant levels of PAH contamination in the surrounding cashew nut processing clusters, and these activities should be controlled.

This study investigates how seasonal variability influences soil metal contamination, spatial distribution, sources, and associated health and ecological risks in a Pb–Zn mining district of southeastern Nigeria. Using ICP-MS analysis, multivariate statistics, and geospatial mapping, we examined Cu, Zn, Ni, Mn, Co, Fe, Cd, Cr, and Pb across dry and wet seasons. Mean metal levels across both seasons followed the order: Fe˃Pb˃Mn˃Zn˃Cr˃Cu˃Ni˃Co˃Cd. Multivariate evaluations predicted anthropogenic sources for Pb, Cu, Cd, and Zn, and geogenic sources for Fe, Co, and Ni. While the mean concentrations of Ni and Co aligned with regulatory and background thresholds, those of Cu, Fe, Cd, Cr, and Pb exceeded them. Non-carcinogenic and carcinogenic health risks were recorded for Cr and Pb across both seasons and exposure groups. Geospatial mappings recorded minimal seasonal variations for Zn hotspots, but high variability for Fe. This study highlights how seasonal variations affect metal pollution patterns in areas affected by artisanal mining. The findings help improve risk assessments, support efforts to protect public health, and guide policies that promote safer and more sustainable mining practices globally.

Rainwater is usually harvested through catchment systems such as roofs or directly from the sky for storage in different vessels for eventual use due to water scarcity which is as a result of increased in water demand, rapid industrialization, increasing pollution, global warming and climate change. This study was carried out to assess the effects of galvanized iron and PVC tanks, thatched roof and industrial activity on harvested rainwater quality by investigating physico-chemical properties, heavy metals, coliform level and metal composition of the storage vessels. Seven-two harvested rainwater samples were collected from four locations in the urban and rural areas of Delta and Enugu States, Nigeria between the months of April-July, 2018. Rainwater samples stored for 1 month to a year in storage vessels were considered. The results were compared with water quality standards (USEPA, WHO, NAFDAC and NSDWQ) and Water Quality Index ratings. Heavy metals (Pb, Fe, Cr, Zn and Al) were analyzed using Flame-AAS; other parameters were determined using standard methods. The WQI ratings were calculated using the weighted arithmetic method. The results were analysed using descriptive and two-way ANOVA statistical analysis. Results obtained in both areas of the States showed mean values ranging from 5.60 ± 0.28 to 7.60 ± 0.20 for pH, E.coli (0.00 ± 0.00–1.00 ± 0.00 cfu/mL), EC (7.00 ± 1.41–108.70 ± 8.62 µs/cm), colour (0.44 ± 0.01–12.86 ± 0.17 TCU) and heavy metals (mg/L) gave 0.00 ± 0.00–1.52 ± 0.13 for Fe, Pb (0.00 ± 0.00–0.29 ± 0.02), Cr (0.00 ± 0.00–0.30 ± 0.05), Zn (0.00 ± 0.00–0.05 ± 0.02) and Al (0.00 ± 0.00–4.65 ± 2.24). The results of the harvested rainwater samples analyzed showed that, the mean values of all the parameters analyzed were below and within the water quality set standard with the exception of a few in both areas in each of the States and were significantly different at (p < 0.05). The results of WQI ratings showed that, harvested rainwater qualities in both States were rated from excellent to unfit for drinking water quality. Generally, harvested rainwater stored in PVC tanks rated better than rainwater stored in galvanized iron tanks though not free of contamination. The storage duration for harvested rainwater is very important for its water quality, hence, harvested rainwater whether it is stored or not should be subjected to treatment before being use for potable usages.

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 level and distribution of Polycyclic Aromatic Hydrocarbon (PAHs) in soil, fruit, and leaf from within automobile repair workshops in Nsukka metropolis was assessed. The PAHs concentrations were evaluated using Gas Chromatography-Mass Spectrophotometer (GC-MS). The health risk was assessed using incremental life cancer risk (ILCR) and mutagenic effect and the possible sources of the PAHs were estimated by the diagnostic ratio. The results showed that the concentrations of the PAHs in soil, fruit, and leaf ranged from 0.003 to 0.564, 0.011 to 0.070, and 0.020 to 0.120 µg/kg, respectively. The mean PAHs concentration for soil, fruit, and leaf are 0.229842, 0.034059, and 0.043091 µg/kg, respectively. The TEQs were generally within the acceptable limit stipulated by Agency for Toxic Substances Disease Registry–ATSDR (100 µg/kg) for non-pollution and low toxicity. The incremental lifetime cancer risk (ILCR) for the seven prominent carcinogenic PAHS indicated that Benzo(a)pyrene and Dibenz(a,h)anthrance, being the most toxic were above the acceptable limit of 1 × 10⁻⁴ showing possible carcinogenic effects to humans with children being the most vulnerable. Although the concentration of PAHs in this study is lower than many similar cases, they have a high risk of carcinogenesis. In contrast, the Mutagenic Equivalent Quotient (MEQ) values were generally within the acceptable value. Benzo(a)pyrene and Dibenz(a,h)anthrance were the most contributors signifying possible alternation/modification of DNA in humans. The Diagnostic ratio showed that pyrogenic combustions could be the main sources of PAHs in the studied area. Therefore, it is evident that Nsukka automobile repair area is gradually being contaminated with PAHs.

Despite the fact that several cases of unsafe pesticide use among farmers in different parts of Africa have been documented, there is limited evidence regarding which specific interventions are effective in reducing pesticide exposure and associated risks to human health and ecology. The overall goal of the African Pesticide Intervention Project (APsent) study is to better understand ongoing research and public health activities related to interventions in Africa through the implementation of suitable target-specific situations or use contexts. A systematic review of the scientific literature on pesticide intervention studies with a focus on Africa was conducted. This was followed by a qualitative survey among stakeholders involved in pesticide research or management in the African region to learn about barriers to and promoters of successful interventions. The project was concluded with an international workshop in November 2021, where a broad range of topics relevant to occupational and environmental health risks were discussed such as acute poisoning, street pesticides, switching to alternatives, or disposal of empty pesticide containers. Key areas of improvement identified were training on pesticide usage techniques, research on the effectiveness of interventions targeted at exposure reduction and/or behavioral changes, awareness raising, implementation of adequate policies, and enforcement of regulations and processes.

Bisphenol-A (BPA) is a notable endocrine disrupting chemical and a core raw material utilised in the manufacture of some food contact materials such as epoxy resin and polycarbonate (PC) plastics. The human health risk (HRI) associated with the migration of BPA into malt drinks packaged in epoxy-cans and stored under various conditions was investigated. Solid-phase extraction (SPE) was used to extract BPA, while analysis was performed with a high performance liquid chromatography coupled to an ultraviolet detector (HPLC-UV). The health risk index was used to assess the likelihood of developing chronic non-carcinogenic health risk among consumers of epoxy-can malt drink. Results showed BPA concentrations at 3.98 ± 0.05°C, 25.34 ± 0.70°C and 30.98 ± 0.27°C range from 0.0166 to 0.0300 μg L⁻¹, 0.0188 to 0.0788 μg L⁻¹ and 0.0217 to 0.2131 μg L⁻¹ respectively. BPA levels in the samples did not exceed the European Union limit (50 μg kg⁻¹). Enrichment levels of BPA in samples stored at 30.98 ± 0.27°C were highest, while that at 3.98 ± 0.05°C samples were the least. Initial migration rate of BPA at 3.98 ± 0.05°C and 25.34 ± 0.70°C decreased with increasing exposure duration, and later maintained a mildly constant rate at longer exposure duration. However, at 30.98 ± 0.27°C, BPA migration rates decreased initially with increase in exposure duration, and increased later at prolonged exposure. Although BPA concentrations showed no significant difference (p > 0.05) at the study’s storage conditions, a significant difference (p < 0.05) was observed in BPA migration rates. The computed chronic non-carcinogenic health risk for daily ingestion of malt drink contaminated with BPA by both adults and children was less than one indicating no probable adverse health effect from consumption of the malt drink.

The study determined the levels of organochlorine pesticides (OCPs) residues and assesses health risks linked with the consumption of vegetables cultivated in the Yamaltu area in Gombe, Nigeria. OCPs residues were solvent extracted and analyzed with a high performance liquid chromatography equipped with UV/VIS Detector. The mean concentrations of ten detected OCPs residues were almost all above the set limit of EU/WHOMRL. The estimated daily intake of OCPs from samples was below the acceptable daily intake, hazard index estimated were <1, indicated no probable non-carcinogenic health effect, while the carcinogenic health effect showed that children were more vulnerable for the consumption of the contaminated vegetables.