Microplastics in the surface waters of the South China sea and the western Pacific Ocean: Different size classes reflecting various sources and transport.

Microplastic transport in the marginal seas is a key process influencing their ultimate fate in the open oceans. In the present study, we collected seawater samples from the western Pacific Ocean (WP) and the South China Sea (SCS) to investigate the distribution, transport, and possible sources for microplastics. Generally, the range of microplastic levels were 187-1816, 146-1563, and 34.

Human health risk assessment of heavy metal and pathogenic contamination in surface water of the Punnakayal estuary, South India.

Variation in levels of toxic heavy metals in river system during the COVID-19 pandemic lockdown might potentially assist in development of a public health risk mitigation system associated with the water consumption. The water quality of Punnakayal estuary in the Thamirabarani River system from the south India, a vital source of water for drinking and domestic purposes, industrial usage, and irrigation was assessed here. A comparitive assessment of physico-chemical variables (pH, EC, TDS, DO, BOD, turbidity and NO), microbiological parameters (total coliform bacteria, fecal coliform bacteria, fecal streptococci and escherichia coli) and toxic metals (As, Cr, Fe, Cu, Zn, Cd, and Pb) suggested a decrease of 20% in the contaminant ratio during the lockdown period in comparison to the pre-lockdown period.

Valorisation of bio-derived fluorescent carbon dots for metal sensing, DNA binding and bioimaging.

Carbon dots are quasi-spherical and zero dimensional nanomaterials with unique optical and electronic properties. In this work, a facile and sustainable strategy was employed to synthesise nitrogen doped carbon dots from Terminalia chebula via hydrothermal treatment with a quantum yield of 19.9%.

Characteristics of microplastics in the beach sediments of Marina tourist beach, Chennai, India.

Marina beach in Chennai metropolitan city attracts numerous tourists from all around the world, and it is an important ecological habitat for many life forms. Rapid urbanisation and industrial developments have led to excessive use of plastics and increased the amount of plastic waste generated in the natural environment. This first baseline study evaluates the microplastic (MP) accumulation in beach surface sediments of Marina and Pattinapakkam beaches through FTIR, AFM and SEM analyses.

Green synthesis of plasmonic nanoparticles using Sargassum ilicifolium and application in photocatalytic degradation of cationic dyes.

In the present work, a green synthetic method for the preparation of extremely stable silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using Sargassum ilicifolium has been demonstrated. Thus produced nanoparticles were characterized by UV-Visible (UV-Vis) spectroscopy, Fourier Transform InfraRed spectroscopy (FT-IR), Energy Dispersive X-ray spectroscopy (EDX), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and Zeta potential analyses. The average size of Ag and Au NPs was 27.

Hydrogeochemical processes controlling the groundwater salinity in the coastal aquifers of Southern Tamil Nadu, India.

The current study identifies groundwater quality issues and investigates the most important geochemical processes that control seawater intrusion using various ionic ratios, hydrochemical facies evolution, and geochemical modelling. Cl/Br ratio is an important indicator to identify the origin of groundwater salinity in coastal aquifers. Nineteen percent of the groundwater samples with Cl/Br ratio similar to that of Standard Mean Ocean Water (SMOW) are affected by seawater intrusion in the study area.

Comparative study of machine learning models for evaluating groundwater vulnerability to nitrate contamination.

The accurate evaluation of groundwater contamination vulnerability is essential for the management and prevention of groundwater contamination in the watershed. In this study, advanced multiple machine learning (ML) models of Radial Basis Neural Networks (RBNN), Support Vector Regression (SVR), and ensemble Random Forest Regression (RFR) were applied to determine the most accurate performance for the evaluation of groundwater contamination vulnerability. Eight vulnerability factors of DRASTIC-L were rated based on the modified DRASTIC model (MDM) and were used as input data.

Measurement of submarine groundwater discharge (SGD) into Tiruchendur coast at southeast India using Rn as a naturally occurring tracer.

Application of natural tracers such as radon isotope mass balance has been useful in estimating the submarine groundwater discharge (SGD). This study used Rn and evaluated the magnitude of SGD at Tiruchendur coast of southeast India in the Gulf of Mannar (Indian Ocean). Higher magnitudes of Rn in the porewater and seawater in comparison with the groundwater suggest simultaneous SGD with fluxes of 0.

Biologically active oxovanadium(IV) Schiff base metal complex: antibacterial, antioxidant, biomolecular interaction and molecular docking studies.

The oxovanadium(IV) Schiff base metal complex (ISNPV) have been synthesized as well as characterized by using micro analytical and traditional spectroscopic techniques. The spectral findings were utilized to validate the formation of ISNPV with structure exhibited square pyramidal geometry. The antibacterial activities of ISNPV were investigated to five different bacterial stains such as , , , and .

Transition metal complexes of 4-hydroxy-3-methoxybenzaldehyde embedded in fly ash zeolite as catalysts for phenol hydroxylation.

The focus of this work is to use fly ash, a waste generated by thermal power plants, to synthesize an economical and efficient heterogeneous catalyst for the fine chemicals industry. To achieve this goal, fly ash zeolite (FAZ) was prepared from fly ash and Cu(II), Ni(II) and Co(II) complexes of 4-hydroxy-3-methoxybenzaldehyde [M(VAN)-FAZ] were loaded in the channels of zeolite matrix by flexible ligand strategy. The prepared FAZ was characterized by XRD, SEM, FT-IR, TGA, XRF and BET analyses.

Site selection of check dams using geospatial techniques in Debre Berhan region, Ethiopia - water management perspective.

Remote sensing and GIS technology were very helpful to determine an appropriate location of freshwater storage in Amhara, Ethiopia. The techniques were used to investigate the impact of lithology, surface geomorphology, slope parameters, drainage flow, drainage density, lineament density, land cover parameters on relief, and aerial and linear features and to understand their interrelationships. Morphometric parameters such as mean stream length (Lsm), stream length ratio (RL), bifurcation ratio (Rb), mean bifurcation ratio (Rbm), relief ratio (Rh), drainage density (Dd), stream frequency (Fs), drainage texture (Rt), form factor (Rf), circularity ratio (Rc), and elongation ratio (Re) were calculated.

Toxicity of Bioactive Molecule Andrographolide against Fab and Its Binding Potential with Detoxifying Enzyme Cytochrome P450.

Fab. is a polyphagous pest causing damage to many agriculture crops leading to yield loss. Recurrent usage of synthetic pesticides to control this pest has resulted in resistance development.

Larvicidal and repellent activity of N-methyl-1-adamantylamine and oleic acid a major derivative of bael tree ethanol leaf extracts against dengue mosquito vector and their biosafety on natural predator.

Aegle marmelos (L.) Correa belongs to the family Rutaceae is generally known as "bael fruit tree" occuring across the south Asian countries. The current investigation screened the main derivatives from crude ethanolic extracts of the Bael tree leaf and evaluated activity effects on the larvae and adults of Aedes aegypti (L.

Appraisal of COVID-19 lockdown and unlocking effects on the air quality of North India.

The COVID-19 pandemic lockdown supposedly provided a 'window' of reinstatement to natural resources including the air quality, but the scenario after the phased unlocking is yet to be explored. Consequently, here we evaluated the status of air quality during the 8th phase of unlocking of COVID-19 lockdown (January 2021) at three locations of North India. The first site (S1) was located at Punjab Agricultural University, Ludhiana-PPCB; the second site (S2) at Yamunapuram, Bulandshahr-UPPCB; and the third site (S3) at Okhla Phase-2, Delhi-DPCC.

Microplastics and trace metals in fish species of the Gulf of Mannar (Indian Ocean) and evaluation of human health.

The importance of microplastic (MPs) contamination in marine environments is reflected by increasing number of studies in fish species. Some even dedicated to the toxicological effects from the ingestion. Microplastics (MPs) and their trace metal composition were examined in the muscle and intestine of five commercially important fish species (i.

Geochemical evolution and seasonality of groundwater recharge at water-scarce southeast margin of the Chihuahuan Desert in Mexico.

Climate models for the 21st century project further reduction in the warm season precipitation and more frequent droughts across Mexico. In the possible scenario of enhanced aridity from global warming, the δO (-10.6 to -6.

Modeling of aquifer vulnerability index using deep learning neural networks coupling with optimization algorithms.

A reliable assessment of the aquifer contamination vulnerability is essential for the conservation and management of groundwater resources. In this study, a recent technique in artificial intelligence modeling and computational optimization algorithms have been adopted to enhance the groundwater contamination vulnerability assessment. The original DRASTIC model (ODM) suffers from the inherited subjectivity and a lack of robustness to assess the final aquifer vulnerability to nitrate contamination.

Effect of COVID-19 lockdown on the water quality index of River Gomti, India, with potential hazard of faecal-oral transmission.

The COVID-19 lockdown has been reported as a "ventilator" for the reinstatement of natural resources across the globe. Hence, the present study attempts to evaluate the impact of COVID-19 lockdown on the water quality of River Gomti across its stretch of ~960 km through the assessment of 'Water Quality Index' (WQI). The study also highlights the potential risk of faecal-oral transmission of COVID-19 through intake of river water facing the issue of direct discharge of domestic sewage.

ANFIS-MOA models for the assessment of groundwater contamination vulnerability in a nitrate contaminated area.

The enhanced assessment of groundwater contamination vulnerability is necessary for the management and conservation of groundwater resources because groundwater contamination has been much increased continuously in the world by anthropogenic origin. The purpose of this study is to determine the best model among three ANFIS-MOA models (the adaptive neuro-fuzzy inference system (ANFIS) combined with metaheuristic optimization algorithms (MOAs) such as genetic algorithm (GA), differential evolution algorithm (DE) and particle swarm optimization (PSO)) in assessing groundwater contamination vulnerability at a nitrate contaminated area. The Miryang City of South Korea was selected as the study area because the nitrate contamination was widespread in the city with two functions of urban and rural activities.

Bioactive platinum complex of ligand bearing pyrimidine skeleton: DNA/BSA binding, molecular docking, anticancer, antioxidant and antimicrobial activities.

A new octahedral platinum complex [PtLCl] of Schiff base ligand containing pyrimidine and morpholine skeleton (where, L is 4,6-dichloropyrimidin-5-yl)methylene)-2-morpholinoethanamine) was isolated and characterized by elemental analysis, H-NMR, FTIR, UV-visible and ESI-MS techniques. DNA interaction of isolated compounds with calf thymus (CT-DNA) was explored by UV-vis absorption, fluorescence, cyclic voltametric and viscometric methods. The result shows that prepared compounds can interact with CT-DNA through electrostatic interactions.

Selective anions mediated fluorescence "turn-on", aggregation induced emission (AIE) and lysozyme targeting properties of pyrene-naphthalene sulphonyl conjugate.

We have designed and synthesized a novel pyrene-naphthalene sulphonyl conjugate, 1-((1Z)-(4-((Z)-4-(pyrene-1-yl)methyleneamino)phenylsulfonyl)phenylimino)methyl)naphthalene-2-ol (PSN) through a facile two-step reactions. It was characterized by various spectral techniques. Fluorescence spectral studies showed that compound PSN featured fluorescence enhancement upon increasing the water content in THF.

Groundwater pollution index (GPI) and GIS-based appraisal of groundwater quality for drinking and irrigation in coastal aquifers of Tiruchendur, South India.

We assessed groundwater pollution index (GPI) and groundwater quality of coastal aquifers from Tiruchendur in South India for drinking and irrigation by evaluating the physico-chemical parameters of 35 samples of mainly Na-Cl type in an area of 470 km with respect to the World Health Organization (WHO) standard as well as by estimating different indices such as total hardness (TH), sodium percentage (Na%), magnesium ratio (MR), Kelley's ratio index (KR), potential salinity (PS), Langelier saturation index (LSI), residual sodium carbonate (RSC), sodium adsorption rate (SAR), permeability index (PI), and the irrigation water quality index (IWQI). Minimal influence of aquifer lithology and the dominant influence of evaporation on groundwater chemistry reflected the semi-arid climate of the study area. Electrical conductivity (EC) of about 89% of the samples across 418 km exceeded the permissible limit and Ca values of 74% of samples, however, remained within the allowable limit for drinking.