Health risk associated with polycyclic aromatic hydrocarbons (PAHs) in dumpsites in southwestern Nigeria

Abstract

Polycyclic aromatic hydrocarbons (PAHs) remain poorly understood, despite their detrimental impacts and role as human mutagens in developing countries such as Nigeria, disruptors, and malignancies. Five dumpsites in South-Western Nigeria were investigated to determine PAH concentrations in soil: Ojota and Oko filling in Lagos state, Ijagun in Ijebu-Ode, Ogun state, and Okitipupa and Irele LGA in Ondo state. The amount of PAHs was assessed using GC-FID. PAHs compounds had limits of detection (LOD) of 0.01 µg/kg, quantification (LOQ) of 0.1 µg/kg, and recovery rates of 82.4 %-95.2 %. At site A (Idimu, oko-filling), BkF had the highest mean PAH concentration (10.94 mg/kg). B(g,h,i)P was second with 3.19 mg/kg, DB(ah)A third with 2.86 mg/kg, and Phen fourth with 1.16 mg/kg, for a total of 19.95 mg/kg. At site B (Ojota dumping), no Flu, Ant, Flt, Cry, B(a)A, B(b)f, or B(k)F concentrations were identified, but the total PAH concentration was 51.44 mg/kg. The highest mean concentration of PAH was B(a)P (35.96 mg/kg), followed by IP (5.43 mg/kg), B(g,h,i)P (4.27 mg/kg), and DahA (3.96 mg). The overall concentration at location C (Ijagun, Ijebu-Ode) was 5.80 mg/kg. Flt Nap, Acy, Flu, Ant, Nap, Pyr, Chry, B(a)A, DB(ah)A, IP, B(b)F, and B(g,h,i)P were not found at site D. The only concentrations listed were Ace (0.74 mg/kg) and B(a)P (1.34 mg/kg). The total concentration measured at Site D was 12.12 mg/kg. Site E, like site D, contained no mean concentrations of B(g,h,i)P, Flt, Pyr, Chry, B(a)A, B(b)F, IP, DB(ah)A, or Ant. The mean organic carbon, pH, and electrical conductivity values were 1.26–1.64 mg/kg, 7.02–8.02, and 84.33–249.33 μS/cm³, respectively. Total PAHs correlated positively with pH but negatively with electrical conductivity and organic carbon. The total HQ value was 1.3 × 10^-4, with individual values ranging from 9.3 × 10^-6 to 2.4 × 10^-6. The data show a substantial ecological risk and potential hazard associated with PAH exposure at a regional dumpsite.