An investigation on the assessment of mercury concentration and its spatial distribution in Kodaikanal Lake sediments, South India

• Published in: Arabian journal of geosciences 2021-08, Vol.14 (16), Article 1629
• Main Authors: Palani, Balamurugan, Vasudevan, Sivaprakasam, Ramkumar, Thirunavukkarasu, Rajendiran, Selvaganapathi
• Format: Article
• Language: English
• Subjects: Accumulation; Anthropogenic factors; Carbonates; Catchment area; Classification (sedimentation); Computer programs; Contamination; Correlation coefficient; Correlation coefficients; Distribution; Earth and Environmental Science; Earth science; Earth Sciences; Ecological effects; Fluorescence; Geostatistics; Heavy metals; Human influences; Lake deposits; Lake sediments; Lakes; Mathematical analysis; Mercury; Metals; Organic matter; Original Paper; Pollution index; Risk analysis; Risk factors; Samples; Sediment; Sediment samplers; Sediment samples; Sediments; Software; Software development tools; Solid wastes; Spatial analysis; Spatial distribution; Statistical analysis; Statistical methods; Thermometers; Water depth; Weight; X ray fluorescence analysis; X-ray fluorescence
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-021-08033-y

In this study, the anthropogenic sources, the toxic concentration of mercury (Hg), and its spatial distribution were investigated by using fourteen different sediment samples, collected from different locations in Kodaikanal Lake. The research was carried out by evaluating different parameters such as sediment characteristics and the concentration of mercury. The study also involves establishing pollution indices like enrichment factor, index of geo-accumulation, contamination factor, and a potential ecological risk factor for the sediment samples. The characterization studies were done by energy dispersive X-ray fluorescence (EDXRF) and the particle size analyzer to determine the concentration of mercury and to classify the sediments based on the size of the particles, respectively. Statistical analysis and the spatial distribution of mercury were assessed by using two different software tools such as Geostatistic (SPSS Statistics software 17.0) and Geostatistics analyst module (ArcGIS 10.1). The weight percentage of sand, silt, and clay in the collected sediment samples were found to be 61.24 to 83.55%, 15.24 to 36.78%, and 0.92 to 1.98% respectively. The weight percentage of organic matter was from 6.00 to 16.00% and total carbonate content varies from 2.22 to 7.54%. The results obtained from the EDXRF confirmed that the concentration of mercury in the collected samples ranges from 19 to 30 mg/kg of sediment and it indicates that almost all parts of the lake exhibit notably higher concentration. Pearson’s correlation coefficient value of 0.74 signifies the association of Hg to the depth of the lake. The high loading values of mud (0.92), Hg (0.91), and water depth (0.86) for PC1 are concerning the 61.10% expressed, the same source for Hg and fine particles and they were, transported and deposited together in deeper depth. The Hg content in the sample to enrichment factor exhibits high to very high (20.95 to 33.81) and index of geo-accumulation with moderate to strongly polluted nature of the sediments (2.34 to 3.00). The fine-grained sediments, water depth, and organic matter were found to be significant controlling factors of Hg distribution in the sediments of the lake. The values of EF and I geo show that the enhancement of sediment by heavy metal (Hg) was by anthropogenic activities such as discharge of the solid waste from the thermometer factory. Additionally, the contamination factor and potential ecological risk factors were calculated as 47.52