Assessment of ambient polycyclic aromatic hydrocarbons in Egbedi dumpsite in Osogbo, Nigeria

Characterization and source apportionment of harbor-derived atmospheric PAHs and the potential risk for public and marine ecosystem health.

Harbor emissions introduce carcinogenic polycyclic aromatic hydrocarbons (PAHs) into the marine environment, posing significant risks. This study investigated the distribution, sources, and risks of 16 priority PAHs in the atmosphere of Tianjin Harbor, one of the world's largest industrial harbors in northern China. A one-year sampling campaign from June 2020 to May 2021 was conducted to collect 35 samples for TSP, PM2.5, and gas phase, respectively, with surrogate recoveries ranging from 75%-125%. Annual mean total PAH concentrations in TSP, PM2.5 and gas phase were successively 104.49 ± 88.06 ng/m3, 56.19 ± 49.93 ng/m3, and 246.34 ± 169.30 ng/m3, with peak levels occurring in winter. The partitioning mechanism (slopes > -0.6) was dominated by the absorption into organic matter based on the gas-particle partitioning analysis, indicating strong local source influence. Local combustion sources, including biomass/coal burning (dominant in winter) and vehicle/ship emissions (year-round) were identified as the main contributors based on convergent evidence from PSCF, diagnostic ratio analysis, and positive matrix factorization (PMF). The incremental lifetime cancer risk (ILCR) from inhalation exposure exceeded the acceptable level of 10-6, with >99% of Monte Carlo simulations indicating a potential carcinogenic risk. The estimated dry deposition flux of total PAHs (ΣPAHs 138.26 ± 114.87 μg/m2/day) was higher than values reported for other coastal regions, implying the substantial input to the adjacent Bohai Sea. These findings underscored the dominance of local combustion emissions and the associated health risks, while suggesting potential ecological concerns related to atmospheric PAH deposition, providing a scientific basis for targeted mitigation measures in major industrial harbors.

Ecotoxicological Risks Associated with Recalcitrant Contaminants from Pharmaceutical Effluents in Selected Areas of Lagos, South-West Nigeria

Polycyclic Aromatic Hydrocarbon (PAHs) Pollution Status of Soil, Water, and Edible Vegetables Within Cashew Nut Processing Clusters in Enugu, Nigeria

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.

Assessment of Polycyclic Aromatic Hydrocarbons Levels in soils from selected automobile workshops

Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous organic compounds generated from a wide range of natural and anthropogenic activities. The study assessed the concentrations of PAHs in soils around automobile workshops in six towns in Delta State (Asaba, Ughelli, Agbor, Effurun, Kwale and Bomadi). Soil samples were collected from four (4) automobile workshops in each town. The PAHs in the samples were extracted with dichloromethane through solid phase extraction and quantified using gas chromatography- mass spectrometry under optimum oven conditions. Data was analysed using Microsoft Excel and SPSS. The ranges of the mean concentrations of the PAHs from the results obtained were Naphthalene - <0.001 to 0.008±0.006 mg/kg; Acenaphthalene - <0.001 to 0.007±0.005 mg/kg; Acenaphthene - <0.001 to 0.003±0.003 mg/kg; Florene - <0.001 to 0.008±0.003 mg/kg; Phenanthrene - <0.001 to 0.030±0.012 mg/kg; Anthracene - <0.001to 0.056±0.033 mg/kg; Fluoranthene - <0.001 to 0.003±0.002 mg/kg; Pyrene - <0.001 to 0.125±0.125 mg/kg; Benzo(a)anthracene - <0.001 to 0.008±0.005 mg/kg; Crysene - <0.001 to 0.001±0.001 mg/kg; Benzo(b)fluoranthrene - <0.001 to 0.003±0.002 mg/kg; Benzo(a)pyrene - <0.001 to 0.006±0.003 mg/kg; and Benzo(k)fluoranthrene - <0.001 to 0.002±0.002 mg/kg. Indeno (1,2,3) perylene, Dibenzo (a,h) anthracene and Benzo (g,h,i) perylene were not detected in any of the samples. The concentrations were within permissible limits recommended by the World Health Organisation. Routine monitoring and mitigation of pollution was recommended to protect the environment and humans from the effects PAHs pollution in the study area.

Polybrominated Diphenyl Ethers in Dust from the Vicinity of Power Generation Plants in Nigeria: Distribution, Risks Assessment and Source Apportionment

Polybrominated diphenyl ethers (PBDEs) constitute a class of widespread environmental contaminants that pose significant health risks. Therefore, this study investigated the distribution, risks and sources of PBDEs in dusts from power generation plants in Nigeria. A total of 24 dust samples were collected from four power plants. Samples were collected for six months covering both wet and dry seasons. Dusts were extracted for PBDEs following the United State Environmental Protection Agency Method 3550C using a 1:1 mixture of dichloromethane and n-hexane. Thereafter, the extracts were cleaned-up and analyzed for PBDEs using a gas chromatograph-mass spectrometer. The results indicated that the mean concentrations of ∑39 PBDEs in the dusts ranged from 17.5 to 54.6 ng g-1 for wet season and 55.4 to 157 ng g-1 for dry season. There were significant spatio-temporal variations in the concentrations of PBDEs in the dust. The PBDEs have higher concentrations during the dry season than the wet season. The hazard index and total cancer risk values indicated that there is neither adverse non-carcinogenic risk nor carcinogenic risk from exposure to PBDEs in these dusts. Source apportionment indicated that the PBDEs in the dusts were from the use of deca- and penta-BDE commercial formulations used for dielectric insulating fluids for transformers, capacitors, cable insulators etc. It is hereby recommended that the Federal Ministry of Environment should establish environmental policy and enforceable regulatory frameworks for the control of PBDEs in order to minimize the levels environmental PBDEs and the risk to human and ecosystems.

Overview on Polycyclic Aromatic Compounds in Water and Sediment Samples in Vietnam

Polycyclic aromatic compounds (PACs), notably unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs), are a group of organic pollutants consisting of two or more fused aromatic rings. They are primarily generated through the incomplete combustion of organic materials and exhibit high toxicity, bioaccumulation potential, and various adverse impacts on ecosystems and human health. The contamination status and distribution characteristics of PAHs and Me-PAHs have been investigated through several case studies in various aquatic ecosystems across Vietnam. However, information about the analytical chemistry and environmental occurrence of PACs in Vietnamese water and sediment samples has not been comprehensively reviewed. Analytical procedures for PAHs in water and sediment typically comprise three main steps: solvent extraction, extract purification, and quantification by gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography with fluorescence detection (HPLC-FLD). PAHs have been frequently detected in Vietnamese water and sediment samples at low to moderate concentration levels. Low-molecular-weight PAHs (LMW-PAHs, 2 to 3 rings) are dominant compounds in water, while high-molecular-weight PAHs (HMW-PAHs, 4 rings or more) tend to accumulate in sediment. Pyrogenic sources are estimated to be more abundant than petrogenic sources. The urbanization process and waste processing activities are major contributors to the emission of PAHs and their derivatives. Additional comprehensive and continuous studies on the analysis and assessment of PACs in Vietnamese aquatic environment are needed.