Estuarine increase of chromium surface sediments: Distribution, transport and time evolution

Chromium is an estuarine contaminant due to its industrial applications like leather tanning, dyeing or chromium plating. The most common explanation about the presence of this metal is the frequent estuarine spill, particularly in ecosystems like rivers, estuaries and coasts near anthropogenic activities.The purpose of this study is the investigation of the distribution and evolution of chromium in sediments of the surface layer of an estuary, determining directly the total content by electrothermal atomic absorption spectroscopy (ETAAS) using slurries. Results were correlated with the environmental conditions and the chemistry of the metal to have a partial overview of the potential risk of chromium presence in the water column and the biota of the estuary. The pH values, oxidation–reduction potential (ORP), elemental analysis (carbon, nitrogen and hydrogen content), and changes of total chromium with time were analysed. This information was used to establish the environmental conditions where chromium appeared, was transported and was accumulated in the marine sediments collected following a time evolution of two years.