Determination of polycyclic aromatic hydrocarbon (PAHs) in soil and plant samples

Environment pollution to dangerous and poisonous chemical substances is one of the major problems which industrialized world counters with. Among pollutants exists in environment, persistent organic pollutants (POP), polycyclic aromatic hydrocarbon (PAHs) In case of existence in food chain, polycyclic aromatic hydrocarbons are one of the most worrying indices and threats for living things. Vegetables are one of the most important food resources and provide main part of energy, cellulosic substances, and vitamins which are necessary for people. Therefore, planting and developing them is really important. Moreover, such products must be provided carefully according to their importance and usage.Kerosene usage in some farms in Khuzestan Province such as Dezful, Safi Abad as herbicide leads to soil and vegetables pollution specially carrot in these farms. Kerosene density increase leads to polycyclic aromatic hydrocarbons in soil and plants. It also increases the density of zinc, copper, lead and cadmium significantly in roots and other parts of vegetables. The current research aims to measure petroleum pollutant and also heavy metals in soil and plants sample. in order to extract the polycyclic aromatic hydrocarbons and Aliphatic hydrocarbons in plants and soil samples, Soxhlet extractor and coupled QuEChERS with ultrasonic were used. And in order to measure the PAHs amount, Gas chromatography- Mass Spectroscopy (GC-MS) were used. All the elements exist in soil sample were set by dissolution method with Hydrofluoric acid and Perchloric acid according to ISIRI ۱۱۱۱۵_۱ ۱st. edition standard and Mass Spectroscopy machine- inductively coupled plasma. Lead, cadmium, copper, zinc, and ferrum amount in plant samples were measured by graphite furnace atomic absorption spectroscopy after microwave digestion. Due to volatility of petroleum compounds such as aromatics, dry freeze method was used to dry samples instead of dry oven method.Findings reveal that suggested coupled QuEChERS method with ultrasonic followed by DLLME purification and GC-MS analysis is perfectly able to set very little amount of PAHs in plants and soil samples. According to qualified numbers comparable to other methods, we can point to its good function. The relative standard variation based on six times measuring for ۱۶ PAH is between ۳.۸-۳.۱۰% and for TPH is between ۹۷.۸-۳۰.۱۰%, the recognition limit of ۰.۰۱ – ۰.۱۶ ng/g for PAH and ۸.۹۷-۱۰.۳۰ for TPH and set limit amount ۰.۹۷-۶.۳۴ for PAH and ۰.۱۳-۰.۹۸ ng/g for TPH.