Trends of atmospheric heavy metal deposition in Lithuania
Keywords: heavy metals, concentration, air, precipitation, deposition, trend
AbstractThe results of long-term measurements of heavy metal (Pb, Zn, Cr, Ni, Cu, Mn, Cd, Fe, As, Hg) concentrations carried out at the Aukštaitija and Žemaitija integrated monitoring stations (IMS) are presented in this work. The average annual concentrations of heavy metals in the air in 2007–2008 and in precipitation over the period 2006–2010 are analysed. A higher deposited amount of heavy metals on the Earth’s surface was determined in the western part of Lithuania (Žemaitija IMS) compared with the eastern part of Lithuania (Aukštaitija IMS). Different deposited amounts of heavy metals are related to higher concentration of heavy metals in the air and higher amounts of precipitation in the western part of Lithuania. A decreasing trend of Pb concentration in precipitation and an increasing trend for Cr, Ni and Cu in precipitation and deposited amounts were observed at both stations. Common correlating groups of element concentrations for both stations were established: As–Cd, Ni–Cr–Cu, and Mn–Cu. These groups are probably typical of the entire territory of Lithuania and are caused by long-range transfer of air masses.