Diagnosis of stream sediment quality and assessment of toxic element contamination sources in East Attica, Greece

Diagnosis of stream sediment quality, multivariate statistics and GIS database proved successful tools for assessing As, Cr and other potentially toxic element contamination in East Attica region. Stream sediments are mixtures of sediments, soils and rocks from the drainage basin upstream of the collection site. Stream sediment quality can be used as initial condition in reaction progress calculations to predict the groundwater quality. The type of methodology used in this study consists of chemical analysis, pH evaluation, X-ray diffraction analysis, scanning electron microscope analysis, cumulative probability plots, factor analysis, GIS database and comparison of the sediment contents with quality standards and levels recorded in the literature and quantification of sediment contamination. Relationships between various elements have been identified from factor analysis and reflect genetic associations. A GIS elaboration showed the spatial relationship between high positive factor scores and presence of ore deposits and anthropogenic contamination. There is both natural and anthropogenic input of As in East Attica streams. High Cr and Ni contents in East Attica stream sediments constitute a natural case of contamination. The contamination degree in East Attica streams follows the order: Keratea-Lavrio > Keratea-Artemis > Rafina > Erasinos.