JWSS - Journal of Water and Soil Science

Dust deposited on the leaves of trees can be effectively used as the monitors of polycyclic aromatic hydrocarbons (PAHs). The dust deposited on the leaves can be used as an appropriate index for evaluating PAHs in the atmosphere. This research was conducted to determine the origin and health risk assessment of PAHs accumulated on the leaves of trees in the city of Ahvaz. For this purpose, samples were taken at leaves on 10 points with different land uses including industrial, recreational, high-traffic and residential ones. After preparation, to determine the type and concentration of PAHs, the compounds were analyzed by GC-MS. The results showed that 15 types of PAHs had been identified from 16 important compounds identified by EPA in the dust samples. The concentration of compounds was the range of 3.3-110 microgram per kilogram. The maximum and minimum of PAHs carcinogenic in particles trapped on leaves were in the Kut-Abdolah with 530 ppb and Shahrvand Park Station with 5.13 ppb, respectively. Also, the average relative of LMW/HMW in the aromatics contained in the deposition of particles on trees was 0.5; further the analysis of the main components of aromatic hydrocarbons (PAHs) showed that there was  no specific source for these compounds in Ahvaz, and these compounds could be from fossil fuels, urban traffic, natural gas,   generally showing a pyrogenic origin.

Street dust is mainly affected by the pollution of polycyclic aromatic hydrocarbons (PAHs). PAHs are a group of organic pollutants consisting of two or more benzene rings and are mainly produced during incomplete combustion. PAHs have attracted widespread attention due to their high carcinogenic and mutagenic properties in humans. Therefore, the purpose of this study was to investigate the sources and extent of the impact of these compounds on human health and the environment. To achieve this goal, 30 dust samples were collected from the sidewalks of the main streets of Dezful and the concentration of PAHs was determined by gas chromatography-mass spectrometry (GC-MS). The total concentration of PAHs in street dust of Dezful varied from 562.85 to 51447.10 μg / kg. The ratio of carcinogenic compounds to total PAHs was in the range between 0.73 to 0.91. Low molecular weight and high molecular weight PAHs accounted for 12% and 88% of total PAHs, respectively. The most important sources of PAHs in Dezful are the combustion of fossil fuels and petroleum products and emissions from vehicles and traffic. Moreover, incremental lifetime cancer risk (ILCR) in pathways ingestion in children was higher than in adults, but the ILCR in pathways dermal contact and inhalation in adults was higher than in children. The total cancer risk (CR) for children (5.77×10^-3) was higher than adults (5.56×10^-3), which shows the high potential for CR in the study area.