JWSS - Journal of Water and Soil Science

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.

In the past years, by increasing population and water consumption, as well as the high cost of developing surface water resources, the exploitation of groundwater resources has increased significantly. In the current situation, a significant part of the country's water consumption in all sectors of consumption is provided by groundwater sources. On the other hand, the development of industry and the entry of pollutants, including heavy metals, into the groundwater endanger the health of humans. The present research has investigated the non-cancerous risk caused by heavy metals in the groundwater of Urmia plain for both children and adults. This research is based on a descriptive-analytical method based on the available data, in which the concentration of polluting metals obtained from the studies conducted in the fall and winter of 2016 from the number of 12 wells supplying rural drinking water in the Urmia plain has been analyzed. Also, human health risk assessment was measured using the United States Environmental Protection Agency index. The results showed that there are six heavy metals including cadmium, copper, iron, manganese, nickel, and lead in the region's groundwater, among which two of the wells have cadmium and lead values higher than national and international standards. Also, the total non-cancer risk index through ingestion and skin absorption for both children and adults groups was found to be 0.23 and 0.096, respectively, which is less than one, and this indicates that the water quality of the region is suitable for drinking.