An environmental magnetic record of heavy metal pollution in Vembanad lagoon, southwest coast of India

MARINE POLLUTION BULLETIN

卷:167

Article

Narayana, A. C.¹  Ismaiel, M.¹  Priju, C. P.² 

[1] Univ Hyderabad, Ctr Earth Ocean & Atmospher Sci, Hyderabad 500046, India

[2] Ctr Water Resources Dev & Management, Kozhikode 673571, India

关键词: Environmental magnetism;    Heavy metals;    Coastal sediments;    Vembanad lagoon;    Southwest coast of India;   

DOI  :  10.1016/j.marpolbul.2021.112344

来源: Elsevier

【 摘 要 】

Magnetic signature of the iron-bearing minerals archived in sediments is sensitive to change in environment and therefore, studied to reconstruct the signals linked with environmental processes. In the present work, we have analyzed 11 sediment cores from Vembanad lagoon, southwest coast of India, to estimate the magnetic fluctuations associated with environmental processes. Down-core variation in magnetic susceptibility and anhysteretic, isothermal and saturation isothermal remnant magnetization and S and H-ratios have been interpreted to map the degree and spatial distribution of anthropogenic pollution in and around the lagoon. Downcore variation of magnetic susceptibility of Vembanad lagoon sediments varies from 10 to 100 x 10(-8) m(3)/ kg. The top layers of sediment samples from river mouth regions (Periyar and Muvattupuzha rivers) show higher susceptibility values and incidentally these samples are of coarse sized. The subtle variations in SIRM/chi(lf) ratios suggest that there are magnetic grain size differences in the samples. The SIRM and chi(lf) relation suggests that dominant magnetic grain size in sediments. The low ARM/chi(lf) ratios suggest a relatively higher ferrimagnetic contribution and coarser magnetite grain size. Rock magnetism data reveal that the coarse magnetic grain size is affecting the pollution of Vembanad lagoon. We also analyzed downcore variability of metal concentrations such as Fe, Mn, Cu, Zn, Ni and Cr, and all these metals exhibit higher concentrations in the top layers of the cores. Our study suggests that higher values of magnetic parameters and metal concentrations are due to various anthropogenic sources.

【 授权许可】

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