Polycyclic Aromatic Hydrocarbons, PAHs Contamination Levels and Health Risks in Foods Consumed in Nigeria: A Review

Abstract

The rate of increase in the number of cancer patients in Nigeria is alarming and calls for constant investigations into polycyclic aromatic hydrocarbons, PAHs and other pollutants. PAHs can be explained as a set of organic compounds which are generated and dispersed into the atmosphere as a result of incomplete combustion of organic materials such as crude oil, coal, wood, and are carcinogenic and genotoxic in nature. They are generally found in various components of the natural environment such as foods, soil, air, water This study aimed at developing a comprehensive report on PAH pollution and its human health risks recorded in the Nigeria. Fifteen studies were selected on PAHs contamination levels and health risk assessment in the following food categories: grains and grain products; seafoods; protein foods; leafy and fruit vegetables. The selected studies were reviewed based on the following information: authors, year of publication, aim of study, area of study, period of sampling, type(s) and number of samples collected, analytical technique, number and concentrations of PAHs identified, risk assessment and potential sources (in some of them) of PAH pollution in the study area. The margin of exposure, MOE adopted by the European food security authority, EFSA Scientific Committee and based on the bench mark dose lower confidence limit for a 10% increase in the number of tumour bearing animals compared to control animals (BMDL10) was used for risk assessment of genotoxic and carcinogenic substances. The values of MOE (calculated by dividing the lowest BMDL10 values with the estimates of dietary exposure to benzo[a]pyrene (0.07), PAH2 (0.17), PAH4 (0.34) and PAH8 (0.49)) obtained in the reviewed studies were mainly higher than 10,000. This according to EFSA indicate low concern for human health and considered low priority for risk management actions. While few recorded MOE values less than 10,000 indicating concern for human health. Some reviewed studies reported mean values of PAHs low than the permissible limit by some regulatory bodies while some reported higher values. It is recommended that prompt action should be taken by the Policy makers and stakeholders to ensure human health protection and also future studies should focus on PAH pollution in fruits, vegetables, farmlands, soils, water, ambient air and the human health risks involved in each case