Analytical investigations concerns regarding Ni and Pb distributions and mobility in river sediments affected by minning activities

The heavy metal pollution is among the most disseminated environmental contamination, at least in some regions of Romania, having a particularly adverse effect on surface water and sediments in affected areas. This type of contamination could be directly linked to some industrial activities like smelting and mining. The main task of this study is to assess the heavy metal outflow from the contaminated sediment to the aquatic environment, with its subsequent toxic effect on the living organisms in water. In this paper we study the distribution and mobility of nickel and lead in sediment samples taken from a highly heavy metals polluted area, the principal anthropologic input being from existing and former mining activities. The main objective of this study was to evaluate the ecological pollution degree by determining the mobility and distribution of nickel and lead in sediments of rivers polluted by industrial human activities. In order to determine the mobile fraction of nickel and lead in sediment samples we used BCR extraction method that separates three fractions which differ in the mobility of existing metal chemical species and a method of leachable extraction fraction by cold extraction method using certified reference material. Our results show that by applying BCR sequential extraction method on sediment, it is found that nickel due to its higher mobility than lead, induce a significant degree of pollution by its migration from sediment to surface water.