Scientists of the Frank Laboratory of Neutron Physics in cooperation with a Mongolian scientific centre are conducting ecological studies in Ulaanbaator, Mongolia, one of the ecologically dirtiest capitals of the world. One of the world largest thermal power plants operating on brown coal is located there.

The products of coal combustion are daily inhaled by citizens of the city and its suburbs, especially in winter when the temperature drops to minus forty degrees, so especially large amount of solid fuel is burned. During the heating period, there is heavy smog in the Mongolian capital. The reason for it is that the city is located in a hollow surrounded by mountains, the weather is windless, and the air almost does not move. These circumstances have an extremely negative impact on people’s health. For example, increased number of blood cancer cases is observed among children living in the region.

A participant and one of the initiators of the research Tsog-Ochir Tsendsuren, an employee of the Laboratory of Functional Materials of the Institute of Physics and Technology of the Mongolian Academy of Sciences (IPT MAS) and a junior researcher of the FLNP Sector of Neutron Activation Analysis and Applied Research, said that in the last ten years, Mongolia had been paying much attention to the assessment of air quality in Ulaanbaatar. “It’s an essential for us study. Ulaanbaatar is a city where a critically severe air pollution is observed. It is necessary to assess the quality of toxic elements in the air and define the factors that influence the health of people, especially of children. That is why we are now conducting these investigations, which will help to understand what measures to take to solve this problem,” the scientist said. The work is carried out within the IPT MAS-JINR cooperation. Moreover, a city grant for materials and equipment have been allocated for research in Ulaanbaatar.

There are 13 officially operating stationary stations for air quality monitoring in Ulaanbaatar (some of them are located 2-3 km away from the thermal power station). They measure the content of ozone, carbon dioxide and monoxide gases, sulfur dioxide, and nitrogen dioxide. Moreover, the content of PM2.5 and PM10 fine dust is surveyed. These are dust particles no more than 2,5 and 10 microns in size respectively that cannot be seen by a human eye. Thanks to their size, they are able to overcome natural protective barriers and get deep into lungs. Fine dust particles may cause serious pathologies in humans. However, stations do not assess the content of various chemical elements at dust particles, which will be done within the study conducted at JINR.

“Stations monitor a fairly limited number of parameters, mainly gaseous compounds, as well as PM2.5 and PM10. Our task has complemented what is already underway,” the scientific leader of research, Head of the FLNP JINR Sector of Neutron Activation Analysis and Applied Research Inga Zinicovscaia said.

Mosses have been preliminarily collected in an ecologically clean area of Russia. They have been purified, dried, and packed for the study into plastic mesh bags. After that, upon the agreement with the Municipality of Ulaanbaatar, they have been placed at all 13 air monitoring stations and removed at various intervals from 1 to 9 months. Then, Mongolian colleagues have sent the material back for study in Dubna. In total, there are almost 400 samples, most of which is ready for elemental analysis.

Until the end of the summer, JINR will carry out a multi-element analysis for the content of 15 chemical elements. These are mainly toxic heavy metals, like chromium, nickel, zinc, iron, barium, strontium, aluminium, mercury, vanadium, lead, cadmium, copper, arsenic, antimony.

The air quality analysis with the use of mosses biomonitors (Sphagnum girgensohnii) is simple, cheap, but at the same time highly accurate. Moss is a unique natural biomonitor. Without a well-developed root system, it accumulates harmful substances from the air as well. The construction of cover tissues of mosses ensures the penetration of chemical elements into their cells, where they participate in metabolism processes. Moreover, moss remains viable even in a dried state, in heat and frost, which allows using it for scientific purposes.

FLNP JINR has assessed the content of mercury accumulated in mosses using the direct mercury analiser. Other chemical elements cannot be determined by the neutron activation analysis method due the the temporary shutdown of the IBR-2 reactor. That is why scientists will use the method of inductively coupled plasma atomic emission spectrometry (ICP-AES).

“We work with solid samples at the REGATA facility, whereas in this case we first apply concentrated acids to mosses to make solutions. Only after it we can determine the content of elements in them,” Inga Zinicovscaia said. “Moss is an object of wildlife, it initially contains various chemical elements. That is why FLNP researchers keep a part of the samples as control ones. We have initial data, we compare everything accumulated in the exposed samples to it thus to understand the content of which elements has increased and decreased in mosses,” she explained.

The first results of the study on 15 elements will be known at the end of June. At the moment, scientists have been able to assess the mercury content in moss samples. This value has increased by 20% in samples exposed during a month compared to the control samples, whereas the mercury content in moss samples exposed during three months has increased up to 50 % compared to control samples kept in FLNP. The highest accumulation has been observed at point 1-р Khoroolol in the Songinokhairkhan district, which is the second district in terms of the size of the area and population after Ulaanbaatar. Scientists hope that they will manage to interest the Municipality in their conclusions and expand the study by adding soils to determine also the radionuclide content.

Moreover, it would be difficult to get access to epidemiological data of Mongolia without the help of the Municipality. “There is a number of indexes that allow assessing the risk of a content of this or that element in particular concentration being harmful for the health of an adult or a child,” the Head of the Sector of Neutron Activation Analysis explained. “That is why our task is to find a link between the results of our research with illness frequency in periods when emissions from the thermal power plant are maximum (in winter).”

Inga Zinicovscaia also noted that the Sector has been conducting studies with the use of mosses biomonitors (“mosses in bags” technique) for ten years already in many countries, including Serbia, Romania, Moldova, Azerbaijan, and Russia. However, the Mongolian capital has become the first place where efforts of scientists have been supported by the city authorities. She also noted the enthusiasm and high organization level of Mongolian colleagues in the working process.