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The aim of this study was to elucidate the contaminant sources and the processes controlling the groundwater quality and risk assessment of heavy metals posed on humans by statistical indices. The groundwater sampling was performed at Bodhjungnagar Industrial Estate, A.D. Nagar, Dukli and Badharghat Industrial Cluster, Tripura, India during pre-monsoon and post-monsoon in the year 2017. A total of 21 water quality parameters (Temp, pH, TDS, Ca, Mg, TH, Na, K, HCO3, Cl, SO4, PO4, NO3, F, Fe, Mn, Pb, Cd, As, Cu, Zn, and Cr) were determined from collected samples. The statistical and graphical methods were employed to assess the suitability of water. The water quality index (WQI) suggested that the majority of the samples are suitable for drinking purpose. The WATEQ4F model was applied to compute the saturation index (SI) of different minerals present in the water samples. Based on Piper plot the dominant water type is Ca-Cl in the study area. The Nemerow integrated pollution index (NIPI) indicates that the groundwaters of both industrial sites have moderately to highly deteriorated water with heavy metals. The hazard index (HI) revealed that amongst the population, chronic health risk was greater for children and considering the seasons, the risk was higher during the pre­monsoon season. [ABSTRACT FROM AUTHOR]

Climate changes on the Southwest coast of India have essential impacts on social and economic development, and the ecosystem of Southern India. Here, we present the last 2000 cal yr AD rare earth elemental records of the sediment core from the Cherai, Kerala coast, southwest India. The light rare earth elements (LREE) were the most abundant fraction in the core sediment, followed by medium rare earth elements (MREE) and heavy rare earth elements (HREE). Total REE (ΣREE) showed a significant correlation with fine fractions and Y, Al, Ti, Fe and total organic carbon content of the sediments, suggesting an intrinsic relationship between REE, total organic carbon and fine grain-size fraction. The LREE and MREE were enriched over the MREE due to their high adsorption with the fine fraction. The lack of correlation between terrigenous elements and low Y/Ho elemental ratio suggests a minor shift in the source materials. High ΣREE values during warm (Medieval Warm Period/ Medieval Climate Anomaly (MWP/MCA) and cold Little Ice Age (LIA) periods indicate a high influx of lithogenous materials during these intervals. The negative δCe values except MCA suggest a suboxic condition and the δEu values suggest feldspar-rich source rock material derived from moderately weathered sediments. It also indicates that the REE variations are controlled by factors like river supply, biological productivity and redox condition. A close link between monsoonal precipitation and REE records existed on the southwest coast of India. During the Dark Age Cold Period (DACP)/MWP transition, a sudden increase in monsoon is documented and the monsoon precipitation was further decreased during LIA and Current Warming Period. The Cherai core REE records synchronize with the episodes of centennial-scale warm/cool events and essentially follow the northern hemispheric climate cycles. [ABSTRACT FROM AUTHOR]

Triterpenoids and fatty alcohols were identified from the sediments of five mangrove ecosystems (Kunjimangalam, Pazhayangadi, Pappinissery, Thalassery, and Kadalundi) in the northern Kerala coast, India, to illustrate the organic matter sources. Straight chain fatty alcohols in the range C12–32 were detected, and among these the long chain fatty alcohols (C20–32) were exclusively even chained compounds. Branched fatty alcohols (6,10,14-trimethyl-pentadecan-2-ol and 3,7,11,15-tetramethyl-2-hexadecanol) of bacterial origin were detected in a few observations. Twenty triterpenoids were detected from the study region in which 13 of them were sterols. Triterpenoids originated from higher plants such as stigmasterol, campesterol, β-sitosterol, taraxerol, lupeol, germanicol, β-amyrin, α-amyrin, and betulin were identified in the study. Brassicasterol, a diatom marker and dinosterol, a dinoflagellates marker were also detected in the study region. An elevated % composition of dinosterol and dissolved oxygen super-saturation were noticed in Kunjimangalam during pre-monsoon, which may suggest elevated input of algal organic matter in the mangrove system. Cholesterol transformation products such as coprostanol and epi-coprostanol were detected, which indicated the presence of fecal contamination in the sedimentary organic matter. From the ternary diagram, it was recognized that the organic matter contribution from marine algae was feeble as compared to terrestrial input. [ABSTRACT FROM AUTHOR]

Structural characterization of fulvic acids (FAs) along with the essential heavy metals (Fe, Co, Zn, and Cr) was carried out in the surface soil samples of prominent mango orchards in Palakkad district, Kerala, India. The FAs were examined with the help of elemental analyzer, UV-Visible, and FT-IR spectroscopy. The heavy metal distribution in the soil was observed in the following order: Fe > Cr > Zn > Co. The statistical analysis indicated the lithogenic and agricultural origin of metals in the study area. The detected level of Fe from the sampling sites was higher than the WHO guideline, while Co and Cr concentration exceeded the USEPA guideline values. The influence of cation exchange capacity, clay content, and CaCO3 of soil over the fate of heavy metals was identified through canonical correspondence analysis. The aliphatic and oxidation degree of FAs was examined using UV-Visible absorbance ratios, atomic ratios, and elemental composition. Results revealed that aliphatic moieties and polar functional groups enrich the FAs in the study area. Pearson correlation analysis exposed the dominant role of FAs in the fate of metals along with the other soil properties. These outcomes provide necessary information that might be useful in the assessment of risk/deficiency associated with the heavy metals in agricultural soils of the study region. It emphasizes the necessity of soil constituent evaluation before crop cultivation to attain sustainable farming practices. [ABSTRACT FROM AUTHOR]

Surface sediment samples were collected from five stations along the Chitrapuzha River, during the monsoon, post-monsoon and pre-monsoon seasons, and analyzed for biochemical composition, total organic carbon (TOC), total nitrogen (TN), and stable isotopic ratios of carbon (δ13C) and nitrogen (δ15N) to identify the major sources of organic matter. Sediment grain size was found to be the key factor influencing the organic matter accumulation in surface sediments. The δ13C values vary between −27.94‰ and −26.05‰ and δ15N values ranges from −1.66‰ to −4.75‰ in surface sediments. The δ13C values indicate terrestrial inputs from higher plants, while δ15N values suggest decomposition processes in the sediments. The fraction of terrestrial organic matter (TrOM) to the total organic matter (TOM) pool ranges from 41 to 84% in the surface sediments as estimated by δ13C-based two end members mixing model. Intermediate values of TOC/TN ratios signal a combined input of both autochthonous and terrestrial organic matter sources, while protein-to-carbohydrate ratios show freshly deposited detritus in the majority of the stations. The threshold levels of protein, biopolymeric carbon, and algal contribution to biopolymeric carbon (BPC) indicate eutrophic conditions prevailing in the study area. [ABSTRACT FROM AUTHOR]

The Cochin backwaters are facing widespread environmental pollution because of the release of solid wastes and liquid effluents from industrial, domestic, and agricultural sectors. The waters are contaminated with trace metals due to an inefficient waste disposal system. Here, the potential trace metal enrichment in sediments related to human activities was evaluated using an enrichment factor, contamination factor, geo-accumulation index, and pollution load index. Metal concentration ranges in sediments during the monsoon, post-monsoon, and pre-monsoon periods were as follows: Fe (15517-90885 µg/g), Mn (122.5-970.9 µg/g), Co (6.9-41.9 µg/g), Ni (12.9-62.9 µg/g), Cu (15.9-56.8 µg/g), Zn (58.7-888.7 µg/g), Cd (0.9-14.5 µg/g), and Pb (12.7-46.8 µg/g). Data on sediment trace metal concentrations are important for environmental forensic investigations, useful for monitoring (i.e., tracing) sources of contaminants (i.e., metal pollutants) and their impacts, and valuable for tracking the dispersal pathways of contaminants in estuarine environments. [ABSTRACT FROM AUTHOR]