RESEARCH OF HEAVY METALS IN THE ATMOSPHERIC AIR OF GOYGOL DISTRICT AS A BIOINTICATOR

Abstract

The moss technique is widely used to monitor atmospheric deposition of heavy metals in many countries in Europe. State of the environmental and thus the health of the population largely depend on the state of the earth’s atmosphere. The atmosphere basically consists of a mixture of natural gases. In addition, the air can contain pollutant gases, as well as suspensions of liquid or solid particulates. The particulates pass into the air either from natural sources (soil, rocks, water bodies and living organisms) or as a result of anthropogenic activity (industry, transport, fuel, human waste, etc.). Essentially, atmosphere is an aerosol system where solid particulates are dispersed in a mixture gases. Data from existing surveys of heavy metals concentrations in mosses is an invaluable resource for international negotiations on heavy metal pollution. The data from moss surveys allow examination of both spatial and temporal trends in heavy metal deposition, and identification of areas where there is high deposition of heavy metals from long-range atmospheric transport and local sources. Mosses effectively concentrate most heavy metals and other microelements from the air and precipitation. Mosses are usually tolerant to even a high pollution level. The most commonly used moss species in air pollution biomonitoring are Hylocomium splendens, Pleurozium schreberi. It is easy to collect samples, and instrumental analysis of mosses is simpler than analysis of precipitation: the exposure period is easy to determine (3 year growth segments of mosses are usually taken for analysis) they can also be employed for studying temporal trends. The moss biomonitor method in combination with nuclear physics analysis techniques has been regularly used for the past three decades in Western Europe and in Asia as well. Thirty four countries signed the United Nations Convention for control of emissions of heavy metals in the air using biomonitoring (the Aarhus Protocol), Denmark in 1998 (as of 2004, it had 36 signatories). The United Nations Organization established a special economic Commission for Europe intended for shaping the scientific policy of the countries that signet the un Convention in the field of research on the critical ozone levels and evaluation of atmospheric heavy metal deposition in Europe by the method based on the collection and analysis of moss biomonitors. The industrial and agricultural sectors have a significant anthropogenic impact on the environment. Moss biomonitoring technique is the first attempt to study the precipitation of heavy metals in Azerbaijan, a country with different relief and climate, using NAA. The study determined the precipitation of heavy metal pollutants in the Goygol, Dashkasan and Gadabay districts. Moss samples (mainly Hylocomium splendens, Pleurozium schreberi) were collected from the studied areas. Concentrations of 44 elements were determined (Na, Mg, Al, Si, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Mo, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb, Hf, Ta, W, Au, Th, U). The mosses two types Pleurozium schreberi and Hylocomium splendens were taken for atmospheric deposition study of major and trace elements in Azerbaijan. Samples were collected at a distance of at least 300 m from main roads, at least 100 m from roads and at least 200 m from village, in forest glades or in open heath to reduce through-fall effects from the forest canopy. In order to make the moss samples representative for a reasonably large area, each sample was composed of four to six sub-samples collected within an area 10x10 m. Collected samples were stored in paper bags. A separate set of disposable polyethylene gloves was used for collection of each sample. The coordinates of the sampling sites were determined using GPS. The areas selected in the study (Goygol, Dashkasan, Gadabay districts) have long been subjected to intensive pollution by industry and various economic complexes. Especially in recent years, the elemental pollutants in these areas have not been fully investigated. At the same time, systematic information on environmental pollutants and sources of these pollutants, forecasting the levels of concentrations of heavy metals and other pollutants, as well as effective methods to reduce them have not been developed. For the first time, a database on the concentration of 44 elements in moss collected from the western part of Azerbaijan (Goygol, Dashkasan and Gadabay) was obtained. The higher pollution of Dashkasan and Gadabay areas compared to Goygol is due to the higher content of these elements in the rocks of these areas, as well as the presence of high levels of anthropogenic pollution from industrial wastes located in these areas. Multifunctional statistical analysis (FA) was used to identify and characterize various sources of pollution and to indicate the most polluted areas. FA is a very flexible technique for using orthogonal factor gaps and minimizing data matrices using predictions and / or transformations that give a known factor. Multidisciplinary statistical analysis of the obtained analytical results will allow to identify the main sources of pollution and assess the role of long-distance transport of pollutants. Keywords: biomonitor, moss, neutron activation, heavy metal