Heavy Metals in the Sediments of the Chilika Lake, India: Contamination, Source and Toxicity Analysis
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Date
2024
Journal Title
Water, Air, and Soil Pollution
Journal ISSN
Volume Title
Publisher
Springer Nature
Abstract
Lakes are multifunctional waterbodies in terrestrial hydrosphere ecosystems and sediment plays a key role in the liquid�solid junction. The rapid economic development in the post-industrial era had manifold heavy metal concentration compared to background values. The non-lithogenic forms of heavy metals possess toxicity to living beings through bioaccumulation and bio-magnification processes. Chilika Lake (India) is a diversified hotspot region and habitat for many endangered species. Over the years, the lake was affected by anthropogenic activities. So, the present study was undertaken to study the dynamic relationship between heavy metals (Cr, Ni, Cd, and Pb) and sediment matrix and their mobilization behavior to the water phase influenced by sediment properties (pH and TOC). A sequential extraction procedure (SEP) was used to evaluate each chemical form's metal content. The ecological risk of metals was assessed by contamination factor (CF), geo-accumulation index (Igeo), Nemerow index (Iin), pollution load index (PLI), potential ecological risk index (PER), ratio of primary phase to secondary phase (RSP), and mobility factor (MF). Source identification (PCA) was done to chalk out the remedial plan. The spatial distribution revealed greater heterogeneity in metal concentration in the lake. Sediment properties control the mobility of metals thus protecting their quality. The mean concentration (mg kg?1) of metals follows the order of Cr (54.35) > Ni (34.95) > Pb (19.53) > Cd (0.93). The dominance of metal content in the labile fraction was found in Cd (97%) and Pb (70%), which indicates a toxic effect on biota. The average value of MF follows the order of Cd (48%) > Pb (13%) > Cr (11%) > Ni (9%) indicating a dynamic equilibrium between sediment and aqueous phase. Source analysis indicates that Cr and Ni came mostly from natural sources, while Cd and Pb originate from man-made activities. The study revealed that the majority of threat is coming from Cd and Pb. Thus, regular monitoring of sediments, treatment of influx water, use of high-quality fuel in the motorboats and the development of a drainage system are essential to eliminate heavy metal toxicity. � The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.
Description
Keywords
Chilika lake, Ecotoxicity, Heavy metals, Pollution load index, Total organic carbon