Human health hazards of poly aromatic hydrocarbons in Nigerian smokeless tobacco

Recently we investigated the heavy metal hazards of Nigerian smokeless tobacco products 'STP'. Since 'STPs' are advocated as safer alternatives to cigarets, the public health implication should be ascertained. This is a risk assessment of poly aromatic hydrocarbons 'PAHs' in 'STPs' used in Nigeria. Thirty 'STPs' from different parts (South East, South West, Niger Delta and North Central) of Nigeria were studied. The 15 PAHs were assayed using gas chromatographic system (6890 series and 6890 plus) equipped with a quadrupole Mass Spectrometer (Agilent 5975 MSD) after ultrasonic extraction of the 'STPs' and clean up of the extract. Toxicity equivalent of benzo[a]pyrene concentration(μg/kg) in 'STPs'were determined. The daily exposure and the cancer risk associated with exposure to STP were calculated. Sample A1 (south east) had the highest concentration of PAH 225.84 μg/kg, while sampleA3 (North central) had the least PAH concentration of 1.09 μg/kg. 'STPs' from South East showed highest levels of PAHs. The total B[a]P TEQ of the 'STPs' from the South East ranged from 0.24 to 29.23, South West ranged from 0.94 to 14.55, Niger Delta ranged from 2.28 to 22.88, and North Central ranged from 0.11 to 9.47. The calculated risk estimates for 'STPs' from the South East ranged from 5.43 E-05 to 4.50 E-07, South West 2.70 E-05 to 1.74 E-06, Niger Delta 4.30 E-05 to 4.20 E-06, and North Central 1.75 E-05 to 2.08 E0-7. Although the calculated risk estimates seem to be within or below the the U.S. EPA cancer risk range of 1 × 10-4-1 × 10-6, the total B[a]P TEQ of the STPs suggest a more indepth risk assessment in animal model to ascertain the safety of PAHs in Nigerian 'STPs'.