The Burden of Crude Oil Toxicity in the Niger Delta Region of Nigeria

Abstract

Many polycyclic aromatic hydrocarbons (PAH) are genotoxic carcinogens. One of the parent PAH, pyrene, undergoes simple metabolism to 1-hydroxypyrene. 1-Hydroxypyrene and its glucuronide are excreted in urine. Biological monitoring of exposure to PAH is a valid method in predicting harm to humans. Eljarrat and Barcelo, 2003 had reported that on exposure there is a tendency for the PAHs to bio accumulate in fishes and through the food web to humans and posing a risk of causing adverse health effects in humans. High values of urinary TAH correlates strongly with adverse harmful effects in humans and carcinogenesis (Eljarrat and Barcelo 2003, Jian-Min Yuan et al 2013). Polycyclic Aromatic Hydrocarbon (PAH) and BTEX content were consistently higher and was markedly greater in fishes obtained from rivers in areas of crude oil exploration and exploitative activities especially in the Niger Delta region of Nigeria, OGONI than in the fishes obtained from rivers in CHOBA and BAYELSA. High values of TPH, PAH and BTEX in fishes may be used to monitor occupational exposure to petroleum crude. Alani Rose et al estimated values of TAH in their studies in fishes obtained from Lagos lagoon and other rivers around Lagos and stated that the fish PAHs from their study was between 71.670 and 264.610ng/g for the assessed biota. Anyakora and Coke 2006 reported Nigeria’s average of 100ug/Kg. Exposure to PAH from various environmental sources are considered primary risk factor for lung cancer (Jian-Min Yuan et al 2013). Polycyclic aromatic hydrocarbons are a large group of organic compounds included in the European Union and United States Environmental Protection Agency priority list because of their mutagenic and carcinogenic properties (M. J. Ramalhosa et al 2009). Associations between polycyclic aromatic hydrocarbons (PAHs) and colorectal cancer have been reported previously but few studies have characterized PAH exposure using biological measurements. Polycyclic aromatic hydrocarbons (PAHs) are by-products of incomplete combustion of organic materials. Individuals may be exposed to PAHs through various environmental sources including, ambient air pollution, and consumption of polluted sea foods (M.J. Ramalhosa et al 2009). The International Agency for Research on Cancer has classified PAH exposure as a Group 1 carcinogen (“carcinogenic to humans”). Several cases–control studies have reported associations between estimated dietary intake of benzo (a) pyrene a particular PAH compound via polluted sea foods, and risk of colorectal adenoma.