Iranian Journal of

Background and Objective: Air quality and distribution of trace elements in the Tehran metropolis were evaluated using transplants of the epiphytic lichen Ramalina sinensis.
Materials and Methods: Thalli of R. sinensis were collected from a non-contaminated area and transplanted in the six urban sites of Tehran for six months. After the end of the exposure period, the content of twelve elements in lichen was determined by ICP-MS method and the obtained data were evalusted using statistical analysis and various indicators.
Results: Based on the results, the order of mean concentration of the trace elements in the R. sinensis lichen samples was determined as: Ca > K > Fe > Mg > Na > Mn > Zn > Pb > Cr > Cu > Ni > Co and the highest amount of bioaccumulation was found for the essential elements. For sevelar elements, significant differences were observed in various sampling sites. Based on the pollution load indexes (PLIs), two sites at Sharif university and Setad Bohran were more polluted than other areas. Exposed-to-control (EC) ratio values for Pb, Zn, Cr, Fe, Mn, Ni, Mg, and Co were also found in the range of 1.25-1.75. Based on the relative accumulation factor (RAF), the accumulation preference of elements by R. sinensis lichen was observed as Na > Cr > Cu > Fe > Mg > Ni > Zn > Mn > Co > Pb > Ca > K, respectively, which represents the significant ability of this species in the accumulation of elements such as Na, Cr, Cu and Fe. PCA and EF analysis indicated that trace elements adsorbed by lichen were mainly sourced from vehicle transportation.
Conclusion: This study demonstrates the application and importance of R. sinensis lichen in biomonitoring of air pollutants elements in urban areas. This approach can justify the suitability, accuracy and cost-effectiveness of lichen compared to other biomonitors for air pollutants and more importantly highlights its capability to the determination of wide levels of air pollution in large scales.

Background and Objective: Agricultural lands around Tehran may become contaminated due to their proximity to pollution sources and such pollution should be investigated. Therefore, the main objectives of this study were to determine the pollution levels of some trace elements in the agricultural soils around Tehran and to assess the attributed health risks.
Materials and Methods: In this study, 43 soil samples were collected from agricultural lands around Tehran. The soil samples were prepared and acid-digested and the concentrations of Vanadium (V), Lithium (Li), Lanthanum (La), Molybdenum (Mo), and Antimony (Sb) were measured by ICP-OES. Based on the concentrations of the elements in soil, the pollution indices and non-carcinogenic risk (based on Monte Carlo simulation) were assessed.
Results: Among the studied elements, V had the highest concentration (131 mg/kg) followed by La > Li > Sb > Mo. The values of the geoaccumulation index (I_geo) and enrichment factor (EF) were in the ranges of -1.9 to 0.8 and 0.5 to 3.1, respectively. The Nemerow integrated pollution index (NIPI) values were in the range of 1.3 to 2.0. The values of non-carcinogenic risk for Li, Mo, Sb, and V were negligible, but it exceeded the threshold limit for La.
Conclusion: This study showed that the agricultural lands around Tehran are contaminated with studied trace elements to a low to moderate extent. However, an unacceptable non-carcinogenic risk attributed to La was estimated. Therefore, it is essential to pay special attention to the La pollution of agricultural soils around Tehran.