title: Bioaccumulation and cancer risk of polycyclic aromatic hydrocarbons in leafy vegetables grown in soils within automobile repair complex and environ in Uyo, Nigeria.
abstract: Using gas chromatography-mass spectrometry and an incremental lifetime cancer risks (ILCRs) assessment model, the bioaccumulation and cancer risk of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in leafy vegetables (Vernonia amygdalina and Lasianthera africanum) grown in soils within an automobile repair complex environment in Uyo, Nigeria was studied. The total PAHs concentrations recorded for soils ranged from 0.02 to 1.77 mg/kg. The highest level of 1.77 mg/kg was recorded for soils from the main automobile repair complex (site 1). Low molecular weight (LMW) PAHs were predominant although some high molecular weight (HMW) PAHs suites (0.04 mg/kg of chrysene and 0.04 of benzo[k]fluoranthene) were also found in site 1. The leafy vegetables accumulated PAHs were mostly LMW. Accumulation levels were similar but the extent of PAH uptake in vegetables was species dependent as V. amygdalina accumulated more (0.81 mg/kg). The bioaccumulation factors (BaFs) calculated ranged from 0.22 to 0.63 for L. africanum, and 0.18 to 0.55 for V. amygdalina in site 1 where high PAH levels were recorded in soil. Pearson correlation coefficient analysis revealed a strong positive relation between the PAH content of soil and the amount accumulated by L. africanum (r = 0.5) and V. amygdalina (r = 0.8) at p = 0.05. The vegetable's potential to bioaccumulate PAHs is indicative of their use as good bioindicators for PAH contamination in soil. Only two of the USEPA possible human carcinogenic PAHs were detected, and carcinogenic risk assessment based on occupational exposures to soil particles by adults revealed that the total risk level (7.17 × 10-5) contribution from incidental soil ingestion, dermal contact, and soil particle dust inhalation slightly exceed the USEPA acceptable limits (< 1.00 × 10-5). There is a need for public education on consumption of vegetables grown in and around automobile repair complexes across Nigeria.
authors.affiliation: Department of Chemistry, University of Uyo, Uyo, Nigeria. eduinam@uniuyo.edu.ng.|International Centre for Energy & Environmental Sustainability Research (ICEESR), University of Uyo, Uyo, Nigeria. eduinam@uniuyo.edu.ng.
authors.forename: Edu
authors.initials: E
authors.lastname: Inam
authors.affiliation: Department of Chemistry, University of Uyo, Uyo, Nigeria.
authors.forename: Felicia
authors.identifier: http://orcid.org/0000-0001-8971-6715
authors.initials: F
authors.lastname: Ibanga
authors.affiliation: International Centre for Energy & Environmental Sustainability Research (ICEESR), University of Uyo, Uyo, Nigeria.|Department of Microbiology, University of Uyo, Uyo, Nigeria.
authors.forename: Joseph
authors.initials: J
authors.lastname: Essien
mesh_terms: D000328:Adult; D001336:Automobiles; D002273:Carcinogens / Q000032:analysis* / Q000378:metabolism; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009369:Neoplasms / Q000453:epidemiology; D009549:Nigeria / Q000453:epidemiology; D016273:Occupational Exposure / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry* / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000378:metabolism; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism; D014675:Vegetables / Q000737:chemistry* / Q000378:metabolism; D035741:Vernonia / Q000378:metabolism
chemical_list: D002273:Carcinogens; D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants
keywords: Bioaccumulation factors; Cancer risk; L. africanum and V. amygdalina; PAHs; Soils