Enrichment of arsenic in the Quaternary sediments from Ankaleshwar industrial area, Gujarat, India: an anthropogenic influence.

Arsenic (As) contamination of sediments and waters is known from Bengal and other parts of eastern and central India. However, there is paucity of reports that document occurrence of As in Quaternary sediments from western India. In this paper, we report the enrichment of As in the Quaternary sediments of Ankaleshwar area in the western Indian state of Gujarat. Twenty-five surface and five profile samples were analyzed that indicated spatial and vertical distribution of As in the sediments. The As content of fine size fractions (<63 μm) compared with upper continental crust (UCC) and standard shale indicates anomalous As enrichment that is supported by moderate to high geo-accumulation index (Igeo) as well as pollution index (Pi). Enrichment of As is seen in surface sediments from the industrial and urban land use regions, followed by oil field and agricultural land suggesting strong influence of anthropogenic factors. Although the arsenic concentration decreases with depth, the relatively higher values of As coupled with Igeo and Pi index values suggest downward migration of metal that is likely to contaminate groundwater. This calls for urgent remediation so that the ill effects of As contamination can be minimized.