BackgroundUnleaded petrol contains significant amounts of monocyclic aromatic hydrocarbons such as benzene, toluene, and xylenes (BTX). Toxic responses following occupational exposure to unleaded petrol have been evaluated only in limited studies. The main purpose of this study was to ascertain whether (or not) exposure to unleaded petrol, under normal working conditions, is associated with any hepatotoxic or nephrotoxic response.MethodsThis was a cross-sectional study in which 200 employees of Shiraz petrol stations with current exposure to unleaded petrol, as well as 200 unexposed employees, were investigated. Atmospheric concentrations of BTX were measured using standard methods. Additionally, urine and fasting blood samples were taken from individuals for urinalysis and routine biochemical tests of kidney and liver function.ResultsThe geometric means of airborne concentrations of BTX were found to be 0.8 mg m−3, 1.4 mg m−3, and 2.8 mg m−3, respectively. Additionally, means of direct bilirubin, alanine aminotransferase, aspartate aminotransferase, blood urea and plasma creatinine were significantly higher in exposed individuals than in unexposed employees. Conversely, serum albumin, total protein, and serum concentrations of calcium and sodium were significantly lower in petrol station workers than in their unexposed counterparts.ConclusionThe average exposure of petrol station workers to BTX did not exceed the current threshold limit values (TLVs) for these chemicals. However, evidence of subtle, subclinical and prepathologic early liver and kidney dysfunction was evident in exposed individuals.

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Considering the growing population and increasing demand for protein intake, the need for more resources to supply protein is a subject of interest 1. The proteins with marine origin have a significant degree of importance due to their higher protein and omega 3 fatty acid contents 2. With population growth, we witnessed the industrial development and as a result the increasing problem of environmental pollution and food contamination to heavy metals were brought about which require major focus 3. Meanwhile, fish due to aquatic pollution are exposed to different levels of these elements depending on fish size and age and these heavy metals can accumulate in fish tissue at different significant levels. Some large species of fish such as thunnus SPP due to having a special diet that is known as biomagnifications have high concentrations of mercury in their body tissue. Since mercury, arsenic, cadmium and lead, are toxic for humans even at a very small amounts, their exact measurement and identification is important. Biotransformation of mercury changes it into a toxic known as methyl mercury; also, an increase in the nickel intake increases the risk of lung, larynx and prostate cancer 4-7 .