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The present study aims to investigate the contamination of heavy metals in the sediments of a tropical ecosystem, India, and to evaluate the factors responsible for the dominance of specific macrobenthic communities, particularly in estuarine sediments. For the analysis of Cu, Cr, Ni, Zn, Pb and Cd in sediments, acid digestion and subsequent quantification by microwave plasma atomic emission spectroscopy was performed, whereas for Hg determination, cold vapour atomic absorption spectrophotometry was used. The general trend of the heavy metal concentration was observed as Cr Cu Zn Ni Pb Cd Hg, regardless of any seasonal alteration. The estuarine region was considerably contaminated by Cu and Cr (C.F. 2) irrespective of any seasonal difference, and by Cd in 2017 non-monsoon (CF 3). Heavy metal contamination was most pronounced during the monsoon (2018). Estuarine and marine zone together considered as deteriorated zone especially during monsoon seasons (PLI 1, 2018 monsoon) while riverine zone remained poorly contaminated (PLI 1). Clay Loam/Clay/Heavy Clay textures preferred polychaetes and bivalves in the estuarine and marine zone as compared to other macrobenthic communities (OMC). Among the hydrochemical parameters, total dissolved solids in general and euryhaline and slightly alkaline pH preferred domination of bivalves followed by polychaetes in non-monsoon seasons. The trace metal contamination in estuarine sediments increases the concern of bioaccumulation tendency of dominant bivalves of the estuarine and coastal sediments.

This study correlated the abundance of five jellyfish species in the south-west coast of India, South-eastern Arabian Sea, Crambionella orsini, Lychnorhiza malayensis, Chrysaora caliparea, Netrosto...

Owing to the consequences of Anthropocene climate changes, extremes of weather and climate disasters such as heavy precipitation, tropical cyclones, and floods, have strengthened in every region across the globe and are badly affecting the earth system processes. The climate change has a tremendous impact in the Western Ghats, the UNESCO heritage site in India, and has to be studied in detail. Floods are the most common (and among the most deadly) natural disasters bringing heavy destruction in the Western Ghat river basins of India, and the Periyar basin is one among them. The low-lying areas of Periyar river basin (RPLB) is one of the worst affected river basins in the 2018 Kerala floods. Since the basin was continuously monitoring, the groundwater quality has been assessed in Periyar basin during three periods (pre-flood, flood, and post-flood-April, August, and October 2018 respectively) and is described in this paper. Since the water table is shallow in RPLB, floodwaters quickly reach the groundwater table, thus influencing the groundwater quality. So, the groundwater samples were collected from 26 sites in RPLB, and analyzed for quality determining parameters. Parameters like pH, TDS, EC, TH, NH

This research incorporates iron-loaded crosslinked chitosan (CS) polymeric structure into the interlayer lattice space of Montmorillonite clay (MT) to enhance the phosphate adsorption capacity of MT. The synthesized Fe-loaded crosslinked chitosan montmorillonite composite (Fe-CS-MT) is evaluated effectively for phosphate removal from aqueous media. Batch adsorption experiments optimized the influence of adsorption parameters, i.e., contact time (50 min), solution pH (3), and adsorbent dosage (2 g L−1) for phosphate removal. The experimental results of equilibrium and kinetic studies indicated that phosphate adsorption on Fe-CS-MT follows Pseudo-second-order kinetic and Freundlich isotherm models with a high degree of accuracy. A series of analytical tools used to profile the investigated material's surface features involves CHNS Analyser, SEM-EDX, FTIR, XRD, XRF, UV-Visible Spectrophotometer, TGA, DSC, and surface analysis. The calculations of the thermodynamic study confirmed the endothermic and spontaneous nature of the phosphate adsorption process. This study presents an eco-friendly adsorbent tested in natural conditions to assess the feasibility of removing phosphate from an aqueous phase.

The current river basin monitoring study investigates the standards of the quality of the river and well water in a biodiversity-rich Netravati River basin in Karnataka state, India. Water samples were collected from 16 major sampling sites during pre-monsoon (April), monsoon (August) and post-monsoon (October) seasons in 2017 to ascertain its physico-chemical parameters. The results of the tests were compared with maximum permissible limits proposed by the World Health Organisation drinking water guidelines. The Water Quality Index (WQI) and the Irrigation Water Quality Index (IWQI) using parameters such as Sodium Percentage (Na %), Magnesium Hazard (MH), Permeability Index (PI), Sodium Absorption Ratio (SAR) and Residual Sodium Carbonate (RSC) have been determined to provide a better understanding of its drinking and irrigation water quality. The interpreted WQI values of the water in Netravati River vary from 33.21 to 298.66, which fall in the range of excellent to very poor drinking water quality. In the case of well water, 100% falls under the excellent category. Multiple statistical methods like Principal Component Analysis (PCA) and Pearson correlation analysis were used, and the results of PCA were found to be in a correlation with the results of the Pearson correlation analysis method. The study, as a whole, highlights the importance of the application of PCA, WQI and IWQI as standard methods to evaluate the quality of water. The results of the present study could be used to contemplate regulations to improve the water quality standard and help people living in and around the river basin to understand the current status of the water quality they use for various purposes.

The present study aimed to analyse the influence of physico-chemical properties on zooplankton assemblages and species diversity in a lagoon system. The study was carried out in coral reef lagoon of Kavaratti Island, Lakshadweep Archipelago, India during the monsoon of the year 2017. Zooplankton assemblages, distributed among 56 taxonomic units, were found to be dominated by copepods (63.27%, 34 taxa) followed by cladocerans (11.14%, 7 taxa), ostracods (9.87%, 2 taxa), ciliates (6.23%, 6 taxa), chaetognaths (4.32%, 3 taxa), leptomedusae, (1.25%, 1 taxa), and appendicularians (3.92%, 3 taxa). Copepods assemblages showed maximum density of 14326 ind m−3 from S1, in which leptomedusea was the lowest abundant taxa (284 ind m−3). Shannon–Wiener-index between 3.725–3.860 attested to the fact that the species diversity and richness predominated in lagoon than that in offshore. Canonical Correspondence Analysis revealed the environmental parameters influencing the abundance and occurrence zooplankton community in the study area.

The utility of kaolinite clay in removing methylene blue from aqueous solution was successfully evaluated. Batch mode adsorption experiments were carried out to study the extraction of methylene blue using kaolinite clay from aqueous phase by optimizing various parameters such as solution pH, contact time, adsorbent dose, and initial methylene blue concentration. Batch studies indicated that the optimum pH range for the adsorptive removal of methylene blue onto kaolinite clay was between 6.0 and 10.0 at 25°C. The equilibrium models such as Freundlich and Langmuir isotherms were tested and later one was found to be the best fit model for describing the adsorption process.

Adsorption is found to be a feasible technique for the removal of even trace amounts 2,4-dinitrophenol (2,4-DNP) from aqueous phase using active carbon from rubber wood. Prior to adsorption studies, surface and physical properties of active carbon were determined using X-RD, FT-IR, and particle size analyzer. Batch adsorption experiments were carried out to optimize various conditions, such as solution pH, contact time, initial solute concentration, and adsorbent dose, for the effective removal of 2,4-DNP from aqueous phase. The favorable pH range for the adsorption process was found to be 2.0–5.0. The maximum adsorption of 99.9% (24.98 mg/g), 98.2% (49.10 mg/g) and 96.9% (96.89 mg/g) of 2,4-DNP onto active carbon was observed at pH 4.0 for different initial concentrations of 50, 100, and 200 mg/L, respectively. Kinetics and isotherm studies showed that the adsorptive removal process follows pseudo-second-order kinetics and Langmuir isotherm, respectively.