Evaluation of polycyclic aromatic hydrocarbon and heavy metals in packaged white shrimp (Metapenaeus affinis) in Tehran

Heavy metals can easily contaminate the aquatic environment, especially shrimp. Considering the high nutritional value of shrimp and the importance of assessing its wholesomeness, this study aimed to determine the amount of some heavy metals (zinc, lead, arsenic, cadmium, nickel, copper, chromium, mercury, manganese, and titanium) and Polycyclic aromatic hydrocarbon in shrimp samples in Tehran, during winter of 2017. A total of 120 samples of shrimp packaged from 10 equal weight packages with similar production date and size which packed by 5 different companies randomly sampled. To determine the amount of heavy metal concentration, Atomic absorption spectrophotometry and to determine polycyclic aromatic hydrocarbon gas chromatography were used. All of the heavy metals measured in this experiment were found below the standard specified by the World Health Organization. The highest mean concentrations of heavy metals were related to zinc (6193.4 ppb), copper (1597 ppb), and arsenic (496 ppb), respectively, and the lowest mean concentrations were related to cadmium (4.8 ppb). Naphthalene (1.2ppb), acenphetylene (0.14 ppb), chrysene (7.6 ppb), and acenaphthene (5.32ppb) were present in the samples of collected shrimp, the values of which were determined higher than standard except for acenphetylene. Additionally, there was no significant difference between heavy metals and PAHs in cultivated and marine samples. In general, the consumption of these shrimps is not dangerous for humans in terms of heavy metals. However, due to the possibility of transmitting PAHs through the human food chain, contamination with PAHs can be considered as a warning for excessive consumption of shrimp.