Polycyclic aromatic hydrocarbons, PAHs are carcinogenic, mutagenic and persistent organic compounds commonly generated from incomplete combustion of organic matters. Beans, Phaseolus vulgaris and maize, Zea mays form part of staple foods commonly consumed and are highly rich in protein and carbohydrate respectively. This study compared the concentration levels of the sixteen priority PAHs in different types of beans (Potasikum, white iron, brown iron, Gausau and Nija red) and maize (white, yellow and pop corn) obtained from various markets in south east Nigeria. The purchased beans and maize samples were picked, ground and extraction was by sonication with a solvent mixture of dichloromethane and hexane in the ratio of 3:1. The determination of PAHs was by gas chromatography coupled with flame ionization detector, GC-FID. The result showed that the PAHs concentration levels (× 10 -2 µg/kg) of lower molecular weight PAHs, LMW detected in the analyzed beans samples ranged from 8.842±4.743 to 12.590±8.068 in white iron beans and brown iron beans respectively with percentages of 41.09% and 44.90% and 5.998±4.725 to 9.385±11.339 in pop and white corn respectively at 25.58% and 34.46%. While the high molecular weight, HMW PAHs concentration levels (× 10 -2 µg/kg) varied from 12.673±5.554 in white iron beans to 16.998±3.129 in Nija red beans at 58.88% and 63.95% and from 17.84±11.768 in pop maize to 18.153±10.421 in yellow maize at 74.83% and 67.43% respectively. The probable carcinogenic PAH8 concentrations detected varied from (8.875±2.725 to 11.796±3.018) × 10 -2 µg/kg in white iron beans and brown iron beans respectively and from (10.82±6.183 to 13.573±8.789) × 10 -2 µg/kg in pop and yellow maize respectively.. Diagnostic ratio calculated showed fuel combustion to be the main source of emission. The sixteen priority PAHs were detected in all the analyzed samples at a very low concentration levels, lower than the permissible limit of 1.0 µg/kg established by EFSA for cereals and cereal based products. Hence these (PAHs) can at a long time accumulation in the body be very harmful. There is need to establish a permissible limit of PAHs in beans and other legume grains by either European Food Safety Authority, EFSA or other regulatory bodies.

Polycyclic aromatic Hydrocarbons, PAHs are harmful persistent organic pollutants formed by incomplete combustion of organic matter. They are carcinogenic and mutagenic and can occur in foods. These underutilized grains-guinea corn, pigeon peas and bambra nut are commonly consumed in South East Nigeria. This study aimed to quantitatively determine the polycyclic aromatic hydrocarbons contamination levels in these underutilized grains (guinea corn, pigeon peas and bambara nut) commonly consumed in Eastern part of Nigeria. The sixteen PAHs were determined in the grain samples using gas chromatography coupled with flame ionization detector, GC-FID after extraction by sonication. The concentrations (×10 -2 µg/kg) of ∑16 PAHs in the analyzed samples were in the range of 24.07 to 36.49 in red guinea corn and red pigeon peas respectively. The lower molecular weight polycyclic aromatic hydrocarbons, LMW-PAHs total mean concentrations (×10 -2 µg/kg) varied from 6.217±0.442 in red guinea corn to 10.423±6.661 in pure white bambara nut at the percentages of 25.83% and 33.51% respectively. While the high molecular weight polycyclic aromatic hydrocarbon, HMW-PAHs varied from 14.835±7.178 to 27.657±14.190 respectively in white pigeon peas and red pigeon peas at the percentages of 59.34% and 75.79%. The total mean concentration levels (×10 -2 µg/kg) of ∑8 carcinogenic PAHs in samples ranged from 10.913±4.215 in white pigeon peas to 17.444±7.023 in red pigeon peas. The sixteen priority PAHs were detected in all the samples at a very low level, below the maximum allowable limit-1.0µg/kg established by European Food Safety Authority, EFSA for cereals and cereal-based products. But this can be harmful to human being at long time accumulation in the body. Permissible limit of PAHs in legume grains should also be established.