Electroanalytical overview: The detection of chromium

Chromium exerts serious damage to human beings and to aquatic life and is one of the most common environmental contaminant and possess toxicity when present above threshold limits. In comparison with the traditional quantification methods such as atomic absorption spectroscopy (AAS), inductively coupled plasma mass spectrometry, UV-Vis or high-performance liquid chromatography, electrochemical methods towards monitoring chromium ions have the advantages of being portable, rapid, cost effective, simple, sensitive and selective enough to meet regulatory limits. This review presents the recent progress in the field of electroanalysis using different electrode platforms such as solid or screen-printed electrode (SPE) and various functional materials towards chromium determination. The fabrication strategy and the analytical performance of carbon nanomaterials (such as carbon nanotubes and graphene), metal and metal oxide nanomaterials enabled sensors for electrochemical determination of chromium (III) and chromium (VI) ions are summarized systematically. In addition, method validation and the application of these sensors in real samples for the analysis of chromium ions is discussed and future developments in this domain are provided

Sediment geochemistry of coastal environments, southern Kerala, India: implication for provenance

Late Quaternary sediments representing the floodplain, estuary and offshore environments of southern Kerala were investigated to infer provenance. The grain size reveals the dominance of sand to silty clay, clay to clayey silt and clayey silt in the floodplain, estuary and offshore sediments, respectively. The chemical index of alteration (CIA) values and A-CN-K plot attributes to high, moderate and low weathering in floodplain, estuary and offshore regions, respectively. The SiO 2 /Al 2 O 3 values lesser than Post-Archean Australian Shale indicate low to moderate maturity for the estuarine and offshore sediments. The geochemical immaturity indicates its derivation from low to moderately weathered source rocks. The major and trace elemental ratios and discriminant function diagrams attribute that the sediments were derived from intermediate to felsic source rocks. The enrichment of Cr and Ni concentration in the sediments compared to the upper continental crust, related to the contribution of orthopyroxenes, weathered from charnockite and garnets from the granulite terrain, respectively