In the Republic of Kazakhstan, namely in the territories of the Karkaraly National Park and the village of Akzharyk in the Karaganda region, scientists from the Frank Laboratory of Neutron Physics at JINR, for the first time conducted research to identify anthropogenic and geogenic air pollutants. The scientists analyzed samples of leafy green mosses collected in the area and found a total of 39 elements. The research was carried out within the framework of the UNECE International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation) at FLNP JINR. The results of the study were published in the Journal of Radioanalytical and Nuclear Chemistry.

Karaganda region is the largest industrial region of Kazakhstan, a JINR Member State. On an area of more than 239,000 sq. km, there are enterprises and plants of metallurgical, mining, processing and chemical industries, which are key to the country’s economy. There are unique deposits of coal, rare metals, ferromanganese, barite-polymetallic and copper ores. The development of most of them began in the middle of the last century, due to which, at present, an industrial complex of great significance for the state has been formed in the region.

Figure 1. Map of sampling sites in the Karaganda region

The village of Akzharyk in the Aktogay district, one of two sampling sites, is characterized by its geographical proximity to centers of industrial activity. On the other hand, the Karkaraly State National Natural Park is located in a specially protected natural area in significantly different environmental conditions. For scientists conducting laboratory research, vegetative material collected in areas with different levels of anthropogenic pollution is a reliable biomonitor of atmospheric deposition of heavy metals.

Since the early 1990s, mosses have been used to assess atmospheric deposition of heavy metals. Due to the fact that mosses do not have a developed root system, atmospheric precipitation becomes a source of mineral nutrition for these plants. Therefore, bryophytes (mosses) are considered to be natural bioindicators of air pollution. In addition, a significant advantage of mosses over ‘traditional’ monitoring stations built in cities and covering a limited number of indicators is their vast habitat; and, accordingly, they allow for ‘low-cost’ biomonitoring over large areas and have a high accumulation capacity.

The main methods for studying the composition of moss samples were neutron activation analysis (NAA) at the REGATA facility of the IBR-2 reactor and atomic absorption spectrometry. Neutron activation analysis is a method of multi-element chemical analysis that allows the determination of up to 55 elements in samples, from Na to U. The NAA technique makes it possible to determine them in a very wide range of concentrations (for example, from high concentrations of macroelements Na, K, Ca to trace elements U, Th). “However, there are a number of problematic elements for neutron activation analysis, such as Cd, Pb and Cu,” said Inga Zinicovscaia, Head of the FLNP Sector of Neutron Activation Analysis and Applied Research. Since these elements are important for analyzing the environmental situation and are pollutants, an additional analytical technique is used – atomic absorption spectrometry. “This method is based on the resonance absorption of light by free atoms as it passes through the atomic vapor of the sample under study. The absorption of light leads to the excitation of atoms, the resonance spectrum of which is individual for each element,” she explained.

Research team from FLNP JINR, from left to right: Marina Frontasyeva, Inga Zinicovscaia, Nikita Yushin, Alexandra Peshkova and Dmitry Grozdov

To interpret the data from the elemental analysis, factor analysis was used, the task of which, being a statistical method, is to group elements according to their origin, i. e., to find sources of pollution or emissions, which would be common to a given group of elements, and explain the reason for their joint occurrence.

In the study, four groups of elements are identified. The first group includes geogenic elements, such as Sc, Al, Fe, occurring as a result of soil erosion, and elements of industrial origin – Ni, Cr, W, U. The geogenic/anthropogenic association of these elements accounts for 25% of the total variance. The second group comprises Al, Sc, Th, which are of biogenic origin, as well as anthropogenic elements Fe, Co and Cr, the sources of which are coal mining enterprises and metal ores. Their share is 24%. The third group is Ca, Ni, Br, Zn and U, formed mainly as a result of mining and fuel combustion. They account for 19% of the total variance. The last group includes As, the source of which may be emissions from metallurgical enterprises, thermal power plants, cars, as well as Mn and Sb resulting from the production of steel and alloys.

Figure 2. Concentrations of Cr, Ni, Cu, Fe, Pb, Sb, Zn and V in mosses collected in the Karaganda region (in mg/kg)

Thus, having calculated the values of the pollution load index and the potential environmental risk index, the scientists made a logical conclusion: despite such a wide range of some potentially toxic chemical elements and the identified areas with a moderate degree of contamination (the village of Akzharyk and the vicinity of the city of Karkaralinsk), the risk to the health of people living in these territories remains at a minimum level. Detailed results are presented in the paper “Mosses as bioindicators of air pollution with potentially toxic elements in area with different levels of anthropogenic load in Karaganda region, Kazakhstan” by Makhabbat Nurkassimova, Nuriya Omarova, Inga Zinicovscaia, Omari Chaligava & Nikita Yushin. The paper was published in the Journal of Radioanalytical and Nuclear Chemistry.

According to Inga Zinicovscaia, in the future it is planned to conduct active biomonitoring in urban areas using the moss bag technique to measure the concentrations of pollutants. The obtained data are planned to be compared with epidemiological incidence rates.