Бидний тухай
Багш ажилтан
Most of the solid wastes from Ulaanbaatar city during the cold season are ashes from the partial combustion of coal. Burial of the ashes with other solid wastes has affected radioactive isotope levels in the soil. We investigated soil radionuclides 226 Ra, 232 Th, 40 K, and 137 Cs describing soil samples collected from the Naran Enger landfill using gamma-ray spectrometry. The natural radionuclide contents soil were highest underneath the waste buried zone and lowest around the “Ger” areas and the initial reference location. The levels of some isotopes were intense underneath the buried zone ( 40 K) isotope content was two times higher) and some of them ( 137 Cs) were lower, compared to the world average. In our result has shown the Ra eq has ranged between the 69 - 183 Bq kg -1 , and Ra eq of ash was 338.3 Bq kg - 1 , respectively. Then, external and internal hazard indexes were 0.2 and 0.5 respectively. From the Ra eq , H in , H ex , D out , and D in values, we calculated life time cancer risk and we found out that cancer risk between 0.8-1.58*10 -3 . Current values of radium equivalent and hazard indices have found to be within the recommended limits.
The purpose of this study was to evaluate the levels of selected six heavy metals concentrations of common pollutants elements such as chromium, cobalt, copper, zinc, nickel, and lead in the street dust around Erdenet city in Orkhon province, Mongolia in 2020. A total of 12 samples were collected from a variety of different sites, such as the ger(ТMongolian traditional house) district, urban center, mining, industrial areas, power plant, train station.
The purpose of this study was to identify pollution sources by characterizing polycyclic aromatic hydrocarbons from total suspended particles in Ulaanbaatar City. Fifteen polycyclic aromatic hydrocarbons were measured in total suspended particle samples collected from different sites, such as the urban center, industrial district and ger areas, and residential areas both in heating, and non-heating periods in 2017. Polycyclic aromatic hydrocarbon concentration ranged between 131 and 773 ng·m−3 in winter, and between 1.4 and 54.6 ng·m−3 in autumn. Concentrations of specific polycyclic aromatic hydrocarbons such as phenanthrene were higher in the ger area in winter and spring seasons, and the pyrene concentration was dominant in late summer in the residential area. Polycyclic aromatic hydrocarbons concentrations in the ger area were particularly higher than the other sites, especially in winter. Polycyclic aromatic hydrocarbon ratios indicated that vehicle emissions were likely the main source at the city center in the wintertime. Mixed contributions from biomass, coal, and petroleum combustion were responsible for the particulate polycyclic aromatic hydrocarbon pollution at other sampling sites during the whole observation period. The lifetime inhalation cancer risk values in the ger area due to winter pollution were estimated to be 1.2 × 10-5 and 2.1 × 10-5 for child and adult exposures, respectively, which significantly exceed Environmental Protection Agency guidelines.
The purpose of this study was to identify the potential ecological risk index by level of heavy metal concentrations of common pollutants element such as chromium, cobalt, copper, zinc, arsenic, cadmium, lead and molybdenum from street dust in Erdenet city, Mongolia. Heavy metals were measured in street dust samples collected from different sites, such as the urban center, residential areas, ger (Mongolian traditional house) areas, industrial district, mining area, agricultural areas and road intersections. By this study, the concentration of the heavy metals ranged between 0 and 84.78 mg/kg in the street dust samples. The concentration of specific heavy metal such as lead was higher in the sampling point of the waste pond. In this study, the concentration of eight heavy metals as chromium, cobalt, cadmium, copper, zinc, arsenic, cadmium, lead and Molybdenum, and their contamination intensity in street dust samples gathered from the mining tailing pond, around the power plant, and around meanly traffic road of Erdenet-Ulaanbaatar were highest investigated. The contaminated of copper, zinc, cadmium and molybdenum in the tailings pond were higher than Earth’s upper crust, and lead in the waste pond and copper in the mining area had high was caused from mining activity and different anthropogenic source. Concentrations of heavy metals into fine white dust 0.9-1.8 times higher than coarse white dust. The obtained results were compared with the average composition of the Earth’s upper crust which showed the street dust of Erdenet city contaminated mainly by copper, zinc, cadmium, lead and molybdenum with the potential to cause many diseases, including cancer.
