Role of intrinsic physicochemical parameters on multi-element distribution in surface sediment of the Devi River estuary, eastern India

• Published in: Chemosphere (Oxford) 2022-06, Vol.297, p.134195-134195, Article 134195
• Main Authors: Akhtar, Shaheen, Equeenuddin, Sk. Md, Roy, Priyadarsi D.
• Format: Article
• Language: English
• Subjects: Devi estuary sediment; Environmental Monitoring; Estuaries; Geologic Sediments - chemistry; India; Lead - analysis; Metals, Rare Earth - analysis; Rare earth element; Redox condition; Rivers - chemistry; Salinity gradient; Silicon Dioxide - analysis; Source; Water - analysis; Water Pollutants, Chemical - analysis
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.134195

Multi-element composition including rare earth elements (REE) of surface sediment from the Devi river estuary, eastern coast of India, have been analysed in order to study the weathering characteristics and provenance of sediment along with their behaviour under different physicochemical conditions. These sediments with dominantly felsic provenance have undergone low to moderate chemical alterations. Bulk chemical composition is mainly represented by SiO2, Al2O3, Fe2O3 and K2O. Concentrations of Ba, Nb, Pb, Rb, Th and Zr are above their respective upper crustal abundances. High LREE/HREE ratio, negative Eu anomalies, and (La/Yb)n and (Tb/Yb)n values confirm that sediments are dominantly derived from the Eastern Ghat Group of rocks. Upper estuary sediments show negative Eu anomalies which is similar to that of the source. However, positive Eu anomaly is mostly observed in lower estuary. Contrasting Eu anomalies between upper- and lower-estuarine sediments are uncharacteristic of previously studied major global estuaries. Strong negative correlation between Mn and Eu suggests control of redox conditions over distribution of Eu. Concentration of REEs, Sc, Fe, Mo, V, Zn, Zr, Nb, U, Ti, Na and P increases up to 20 ppt salinity, and followed by declining trend towards mouth. This is mostly due to removal through flocculation of colloidal particles from water column during fresh- and saline-water interaction. This could be the first report about coagulation-based behaviour of Mo in estuarine environment. There is gradual decline in concentration of Cr, Co, Ni, Cu, Rb, Sr, Sb, Cs, Ba, Pb, Al, Mn, Mg, Ca and K with increase in salinity which is attributed to saline induced desorption of elements from sediments. The SiO2 content shows increasing trend towards mouth. Findings of this study highlight the importance of intrinsic physicochemical parameters, mainly salinity and redox condition, on governing geochemical behaviour of different elements including REE in mangrove dominated estuarine sediment. [Display omitted] •Provenance and distribution of metals, including REE, in the Devi estuarine sediment is studied.•Sediments are mostly derived for the Eastern Ghat Belt.•Unique contrasting Eu anomalies between upper and lower estuarine sediments are observed.•Behaviour of Mo is found to be similar to that of REE.•Salinity and redox environment play an important role on distribution of elements.