Sediments as Indicators of Heavy Metal Contamination in the Lower Danube River

An essential feature for the evaluation of the status of aquatic ecosystems is represented by the sediment quality assessment, as a constitutive part thereof. Sediments reflect all the processes occurring in the hydrographic basin, acting at the same time as a potential source of water pollutants, especially heavy metals. This paper aims to assess the sediment quality of the lower section of the Danube River, in terms of heavy metals content (Cu, Cr, Cd, Pb, Ni and Zn). For this purpose, 10 sampling locations have been assigned and for a period-of 12 months (September 2013 - August 2014), sediment samples being monthly collected. To characterize the distribution type and the dynamic variation of heavy metals in the studied section, box plot diagrams have been used, and for the sediment quality evaluation, the obtained values were related to chemical quality standards set out in the Romanian legislation (M.O. 161/2006). For a more detailed assessment of the relationship between metals and for identification of anthropogenic and natural sources, Cluster Analysis (CA) has been used. Following this study, an overview of the sediment quality and the distribution of values obtained on the studied section has been achieved.