Introduction: Implementing control plans, monitoring, and formulating traffic and management laws requires obtaining basic information about the origin of particles, physicochemical properties, and their behavior in the atmosphere. Gathering this information requires studying the various dimensions of ...
Introduction: Implementing control plans, monitoring, and formulating traffic and management laws requires obtaining basic information about the origin of particles, physicochemical properties, and their behavior in the atmosphere. Gathering this information requires studying the various dimensions of the nature of particles, most of which will not be directly possible. The challenge of air pollution in the metropolis of Tehran requires fundamental studies, and in this study, we tried to present new dimensions of physicochemical and fundamental properties of atmospheric particles in Tehran. Material and methods: The particle collection process to evaluate their concentration and chemical composition was performed by a high-volume sampler for 1 to 24 hours and an average flow of 1.7 m3/min on fiberglass filters. Also, to determine the aerodynamic diameter distribution of the particles, a cascade sampler (Anderson impactor) with a flow of 28.3.3 L/min was used for 72 hours to 7 days. After sampling, the samples were prepared to determine the total concentration and aerodynamic distribution in the laboratory. Results and discussion: The results showed that the mean particle concentration during the sampling period was 118.6 ± 11.9 µg/m3. During the sampling period, the highest concentration of collected particles was 154.61 ± 22.1 and the lowest was 129/12 ± 23.15 µg/m3. The results of SEM analysis of the collected samples showed that the particles were present in a spherical, irregular, fibrous shape as well as crystalline shape. The predominant elements in these samples are K, Ca, Cl and Fe, which are found in combination with Ti, Zn. Cluster-like and amorphous structures rich in O, Zn, Mg, Fe, K, Si, and Na were observed in particles with dimensions of 2 to 7 micrometers. Conclusion: According to the results and comparison with other work done in this field, more particulate matter is emitted during fuel combustion processes by industry and urban transportation. Larger particles are also produced and emitted by vehicles, construction, and industry during human activities such as road dust.
Hamidreza Pakzad; Hashem Bagheri; Farzaneh Teymouri
Volume 15, Issue 4 , January 2018, , Pages 125-140
Irankuh Pb-Zn mine is located in 20 km SW of Isfahan in the Zayandehrud river drainage basin. Shale and carbonate are host rocks of the ore deposits. High concentration of Pb and Zn formed ore complex in these rocks. Weathering and erosion of the host rocks of ore deposits, waste water ...
Irankuh Pb-Zn mine is located in 20 km SW of Isfahan in the Zayandehrud river drainage basin. Shale and carbonate are host rocks of the ore deposits. High concentration of Pb and Zn formed ore complex in these rocks. Weathering and erosion of the host rocks of ore deposits, waste water and waste material arising from mining have made potential for pollution of running water, ground water and agriculture soils by the heavy metals. The main objectives of this investigation were to study the total concentration of Zn, Pb, Ni,Cu, Co, Ag, and Cd in the shale deposits of the mine and physicochemical factors on their distribution and pollution.
Materials and methods:
For measuring heavy metals values, twenty samples were taken from the shale deposits. For distinguishing the shale forming minerals, thin sections were prepared and studied by polarizing microscope. The rock forming clay minerals, after preliminary treatments (heating at 550oc, ethylene glycol solvation), were detected by XRD. Organic carbon, calcium carbonate and Eh/pH of the shales were measured. Heavy metals values in the sample were measured by AAS after mineralization. Correlation coefficient of organic carbon and Mn with metals and also metals-metals were calculated. For comparison of the heavy metal concentration relative to their natural amount (in shale), enrichment factor was applied.
Results and discussion:
The dark grey to olive colored shales in the studied area consist of clay to fine silt size. Quartz, biotite, muscovite, feldspar and clay minerals are the non-opaque minerals of the shales. The clay minerals are illit (60-70%), kaolinite (9-27%) and chlorite (7-22%) respectively. Sphalerite, pyrite and galena are the main opaque minerals of the mine. The mean OC content of the shale is about 2% (0.35-5.5%) and less than 1% calcium carbonate. The pH of the samples is nearly neutral (6.8-7.8) and they have an oxidizing to nearly reducing Eh (18 to -100 v).
The average concentration of heavy metals in the shales are Zn=128.05>Pb=42.55> Ni=35.24> Cu=24.18> Co=7.4> Ag=3.33> Cd=0.79 in ppm, respectively. Highly positive correlation between Ag-Pb-Cd, Cd-Zn-Pb and Co-Ni-Mn and also positive correlation between Zn with organic carbon show geochemical convenient conditions for concentration of the metals. The calculated enrichment factor has revealed extremely high enrichment for Ag and average for Cd. Other elements are depleted in the sediments. Due to relative high concentration of the metals and their extent of the shales in the study area, activation of the heavy metals in suitable conditions can be a potential source for environmental contamination in the groundwater and runoff water of the basin.