Decreased atmospheric deposition of heavy metals shown by long-term monitoring using the moss Pleurozium schreberi

Abstract In Europe, economical restructuring and technological progress has been aimed at reducing pollution emmissions at local, regional and global scales, which has been monitored using standard methods. Among the many methods used to determine deposition of heavy metals, in Europe moss has been used to monitor atmospheric pollution for more than 30 years on a 5-year cycle. Thus, this simple method can be used to assess improvement to the environment after massive economic change. Using PCA analysis, this study examines the long-term trends of heavy metal concentrations (Cr, Cu, Ni, Pb, V, Zn) in Latvia. There has been an decline in heavy metal concentrations in Latvia related to the closure of large industries after the the collapse of the Soviet Union and due to change in fossil fuels in the energy sector from petroleum to natural gas, but past effect from some sourses is still evident. Increased quality of automobile fuel led to a decrease of lead concentration, and conversion of fuel source in the energy sector from oil to natural gas caused a decline of V and Ni concentration.