Assessment of Polycyclic Aromatic Hydrocarbons inAjakanga Waste Dumpsites in Ibadan
No Thumbnail Available
Date
2025-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Lead City University Ibadan
Abstract
This study investigated the presence, distribution, and health risk of Polycyclic Aromatic Hydrocarbons (PAHs) in soil samples collected from the Ajakanga waste dumpsite in Oluyole Local Government, Ibadan, Nigeria. PAHs are persistent environmental pollutants known for their toxicity and high potential to accumulate in soil and sediments. A total of 65 PAHs were detected in the soil samples using GC-FID instrument, with a focus on the 16 US EPA priority PAHs for in-depth analysis. The overall concentration of the 16 priority PAHs across the sampling zones (Zone A-F) ranged from 12.54 mg/kg to 24.02 mg/kg. These levels significantly surpass the contamination threshold of 1.0 mg/kg established by the Agency for Toxic Substance and Disease Registry (ATSDR) and the European Commission's classification for heavy contamination. The highest concentration of the Σ16 PAHs was observed in the central and western zones of the dumpsite (Zone E: 24.02 mg/kg and Zone B: 23.51 mg/kg). Diagnostic ratio analysis indicated that the PAHs originated from both pyrogenic (combustion) and petrogenic (petroleum) sources. This is supported by the high concentration of both low molecular weight (LMW) and high molecular weight (HMW) PAHs, though HMWPAHs were dominant, suggesting substantial incomplete combustion processes. The dominant PAHs detected were Acenaphthylene, Benzo(b)fluoranthene, and Benzo(g,h,i)perylene. The human health risk assessment revealed a moderate carcinogenic burden, with calculated Benzo(a)pyrene equivalent (BaPeq) values ranging from 0.4901 mg/kg to 0.7970 mg/kg. The incremental lifetime cancer risk (ILCR) estimates for children (2.96×10−6 ) and adults (2.34×10−6) fell within the low-risk category. Furthermore, the non-carcinogenic hazard indices (HI) for both children (4.04×10 −4 ) and adults (2.48×10 −4) were below the threshold of 1, suggesting no immediate health risk from non-carcinogenic effects. The primary route of exposure for both groups was identified as ingestion (80.0%), followed by dermal contact (19.0%), with inhalation being negligible. These findings confirm the high level of PAH contamination in the dumpsite soil, necessitating continuous monitoring, regulatory enforcement, and public awareness campaigns to mitigate long-term exposure risks to the surrounding community.
Keywords: Polycyclic Aromatic Hydrocarbon, 16- priority US, Environmental Pollution Control Agency, Chromatography, GC-FID Instrument.
Word Count: 300
Description
Keywords
Polycyclic Aromatic Hydrocarbon, 16- priority US, Environmental Pollution Control Agency, Chromatography, GC-FID Instrument.
Citation
Kate Turabian