The impact of mercury pollution on ecosystems soil, water / sediment from Olt river basin

Abstract

Mercury is a metal that exists naturally in the Earth’s Crust. It can be released by rock weathering and transported by stream waters and may go through a series of chemical transformation according to the bio-physical-chemical conditions. Thus, in reaction with inorganic ligands or organic matter, different forms of mercury can bioaccumulate in the high organisms through the sediments and the food chain. A fraction of this trace element can be trapped into the soils by close relationship with organic matter, iron and aluminium oxides or sorbed onto the mineral particles. Some natural processes (water, soil and vegetation degassing, volcanic emissions) allow it to degas and to flow back into the atmosphere, creating an atmospheric dispersion and a diffuse deposition on the terrestrial ecosystems. Mercury has become one of the most important environmental pollutants. Due to industrial, domestic and medical activities, the amount of total mercury in the environment and mainly in the atmosphere has been increasing since the 20th century. Approximately 5000 tons of mercury is introduced in the Earth’s atmosphere every year. The main objective of this study is to quantify the real impact of the mercury emissions downstream the chemical plants and to determine the mercury pollution in such an area. This study is not only there to demonstrate the significance of the ecosystems soil, water/sediment pathway in the mercury pollution downstream the human activities, but also to show the major role of the mercury in the persistent contamination of the Olt catchment.