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.
The Niger Delta region of Nigeria is highly vulnerable to environmental pollution due to extensive
oil exploration and industrial activities, resulting in the contamination of aquatic ecosystems with
heavy metals and polycyclic aromatic hydrocarbons (PAHs). This study assessed the
concentrations of heavy metals and PAHs in surface water and sediments of the Khana LGA,
Rivers, Rivers State, to evaluate potential ecological and human health risks. Surface water and
sediment samples were collected from selected sampling stations within rivers in Zaakpon, Kaani,
and Bane communities in Gikana LGA and analyzed using standard physicochemical and
spectroscopic techniques, including Atomic Absorption Spectroscopy (AAS) for heavy metals and
Gas Chromatography-Mass Spectrometry (GC-MS) for PAHs. Results indicated that the mean
concentrations of heavy metals in surface water were Pb (0.285 ± 0.019 mg/L), Cd (0.013 ± 0.004
mg/L), Cr (0.044 ± 0.005 mg/L), and Fe (1.894 ± 0.196 mg/L), with several exceeding WHO and
NSDWQ limits. Sediment samples exhibited higher metal accumulation, with Cu (14.771 ± 1.074
mg/kg), Pb (29.279 ± 3.161 mg/kg), Fe (1826.925 ± 10.798 mg/kg), and Zn (136.356 ± 6.317
mg/kg), indicating sediments act as long-term sinks for metal pollutants. For PAHs, total
concentrations in water ranged from 0.167 to 1.256 mg/L (mean: 0.477 ± 0.075 mg/L), with
carcinogenic PAHs (∑cPAHs) at 0.121 ± 0.024 mg/L, exceeding WHO and USEPA guidelines.
Sediment PAH concentrations were substantially higher, ranging from 6.994 to 20.178 mg/kg
(mean: 11.866 ± 1.274 mg/kg), with both low and high molecular weight PAHs present, reflecting
mixed petrogenic and pyrogenic sources. The study concludes that the Khana Rivers are heavily
contaminated with both heavy metals and PAHs, posing serious environmental and human health
risks. Urgent interventions are recommended, including continuous monitoring of water quality,
enforcement of environmental regulations, remediation of polluted sediments, and community
awareness programs to mitigate exposure to toxic contaminants. The findings provide a crucial
baseline for future ecological risk assessment and pollution management in oil-impacted riverine
systems of the Niger Delta.
Wisdom Osamudiamen Clifford-Osawaru· IIARD International Journal...· 0 citations
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.
D. H. Nguyen, Hường Thị Ánh Nguyễn, Chu Thị Huệ et al.· VNU Journal of Science Natur...· 0 citations
Polycyclic aromatic hydrocarbons (PAHs) in soils of energy chemical industrial plants pose considerable ecological and health risks. However, comprehensive studies between petrochemical and coal chemical plants in arid Northwest China remain limited. In this study, 75 surface soil samples (0-20 cm) were collected from 15 large-scale plants (four petrochemical and 11 coal chemical plants) across the region. Sixteen priority PAHs (∑PAHs) were quantified, and source apportionment was conducted using diagnostic ratios and principal component analysis-multiple linear regression (PCA-MLR). In addition, health risks were evaluated using toxic equivalence factors and incremental lifetime cancer risk (ILCR) models. Results showed a stark contrast in PAHs concentrations, with coal chemical plants averaging 4652.2 ng/g and reaching up to 188,506.0 ng/g at a coal tar processing site, compared to 225.6 ng/g in petrochemical plants. Four-ring PAHs were predominant, accounting for 64.5% and 52.1% of total PAHs in coal chemical and petrochemical soils, respectively, indicative of high-temperature combustion sources. PCA-MLR analysis identified coal combustion as the dominant source at coal chemical sites (96.5%), while petrochemical sites exhibited mixed sources, including oil leakage (49.6%) and vehicular emissions (25.6%). Health risk assessment revealed that ILCR values exceeded the US EPA threshold of 10-6 at seven sampling points in coal chemical plants, with the highest risk observed at site BXT-2 (1.99 × 10-4), primarily driven by dermal and oral exposure to benzo[a]pyrene. These findings highlight the urgent need for stricter control of high-temperature industrial processes and improved management of hazardous waste in energy chemical industrial plants.
Meng-Cheng Wu, Yun-Zhou Tan, Guo-dong Kang et al.· Journal of Environmental Qua...· 0 citations
Soils around petrol filling stations are exposed to polycyclic aromatic hydrocarbons (PAHs) from fuel spillage, storage tank leakage, and incomplete combustion of petroleum products. This study assessed the levels, distribution, sources and health risk of the 16 USEPA priority PAHs in soils around petrol filling stations in Kogi Central (Zone 1: Ajaokuta, Okene) and Kogi West (Zone 2: Obajana, Lokoja), Kogi State, Nigeria. Twelve soil samples from filling stations and four controls were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Surrogate (o-terphenyl) recoveries ranged from 94.0 to 101.6%. Total PAH (Σ16PAHs) concentrations ranged from 0.540 to 5.90 µg/kg, with mean values of 2.55 µg/kg in Zone 1 and 3.45 µg/kg in Zone 2 (combined mean 3.00 µg/kg). A two-sample t-test showed significantly higher PAH concentrations at filling stations than controls (t = -2.30, p = 0.038), with no significant difference among the four towns (p = 0.094). Low molecular weight (2-3 ring) PAHs dominated the distribution (65.7%), followed by 4-ring (30.2%) and 5-6 ring PAHs (4.12%). All individual and total PAH concentrations were below the Dutch maximum permissible concentrations, indicating unpolluted soils. Diagnostic ratios (LMW/HMW = 1.91; Ant/(Ant+Phe) = 0.77; Flt/(Flt+Pyr) = 0.90; BaA/(BaA+Chr) = 0.68) revealed a predominantly pyrolytic origin for the PAHs, with a minor petrogenic contribution. The mean benzo[a]pyrene equivalent concentration (BaPeq) was 0.0595 µg/kg, far below the 600 µg/kg Canadian soil quality guideline, denoting low carcinogenic potential. The results supply baseline data for PAH monitoring in the study area and complement previously published data for Kogi East.
J. A. Kadili, Godwin John, I. S. Eneji et al.· FUDMA Journal of Sciences· 0 citations
The spatial distribution, sources and ecological risk of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) in surface soil from Liuxin area, Xuzhou, China was investigated in this study. Gas chromatography-mass spectrometry analysis revealed ΣPAH concentrations ranging from 115.66 to 373.53 ng ⋅g−1 (mean: 196.26 ng ⋅ g−1), with phenanthrene (Phe) exhibiting the highest mean concentration (51.18 ng ⋅ g−1). Spatial analysis demonstrated a southeast-to-northwest concentration gradient, with maximum PAH levels observed in southeastern zones. PAH composition showed dominance of low-molecular-weight species (2, 3 rings: 46.7%), followed by 5, 6 ring PAHs (28.3%), and 4-ring compounds (24.9%). Source apportionment using molecular diagnostic ratios and positive matrix factorization identified four primary contributors: coal-fired power generation & metallurgical emissions (34%), biomass combustion (31%), diesel fuel combustion/leakage (29%), traffic emissions (6%). Ecological risk assessment employing Dutch soil quality standards revealed localized exceedances in southeastern areas, particularly for fluoranthene (Fla) and Phe. However, toxic equivalency quotients remained low, with incremental lifetime cancer risks below 10−6 for all exposure pathways. These findings indicate that while PAH contamination warrants monitoring, current levels pose negligible carcinogenic risk to the local population.
Jin-Xian He, Chen-Long Ding, Pei-Lin Sun et al.· Environmental Research Commu...· 0 citations
Borehole water is a major drinking water source in Owerri West LGA, Imo State, Nigeria, but fuel
stations within residential areas raise concerns over groundwater contamination by polycyclic
aromatic hydrocarbons (PAHs). This study assessed concentrations of the 16 USEPA priority
PAHs in borehole water near three fuel stations (Nekede, Orogwe, Obinze), evaluated health risks
to adults and children, and identified probable contamination sources. Twenty-seven samples were
collected in the dry season from fuel-station and nearby residential boreholes (25–625 m away).
Physicochemical parameters were analyzed per APHA (2017); PAHs were extracted (USEPA
Method 3510C) and quantified by GC-MS. Health risk was assessed using the USEPA (2014)
deterministic model, with source apportionment via diagnostic ratios and PCA. All
physicochemical parameters met WHO/USEPA limits. Total PAHs (Σ16PAHs) ranged from
0.112–0.217 mg/L, with benzo(a)pyrene exceeding the USEPA limit (0.01 µg/L) in all fuel-station
boreholes. Hazard quotients were below 1, but benzo(a)pyrene cancer risk (7.15×10⁻⁵ adults;
1.67×10⁻⁴ children, Nekede) exceeded the USEPA threshold (1×10⁻⁶), with children ~2.3 times
more at risk. Diagnostic ratios indicated predominantly pyrogenic sources with petrogenic
contribution from fuel leaks. Despite meeting potability standards, the water posed unacceptable
carcinogenic risk, warranting setback regulations and household treatment.
D. L., Oze R. N., B. A. et al.· INTERNATIONAL JOURNAL OF CHE...· 0 citations
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