Interactions between microplastics (MPs) and trace/toxic metals in marine environments: implications and insights-a comprehensive review.

Microplastics (MP) pollution is a pressing concern in today's marine environments. MPs can significantly affect marine ecosystems by altering nutrient and pollutant dynamics. This review analyses the existing literature to investigate interactions between MPs and micronutrients/pollutants, specifically trace and toxic metals in marine environments.

Comparing deep-sea polymetallic nodule mining technologies and evaluating their probable impacts on deep-sea pollution.

Deep-sea polymetallic nodules (PMN) hold promise as a future resource, with various consortia like MOES, IOM, GSR, KORDI, and COMRA actively exploring mining possibilities. However, current technologies lack environmental sustainability. This study comprehensively compares the technologies proposed by different consortia for deep sea mining (DSM).

Investigating the combined effects of pH changes and UV radiation exposure on dissolved metal-humate complexes: an important process in aquatic systems.

An in vitro study was carried out to examine the impact of UV exposure on metal-dissolved humic material (M-DHM) complexes in aqueous systems at different pH. Complexation reactions of dissolved M (Cu, Ni, and Cd) with DHM increased with the increasing pH of the solution. Kinetically inert M-DHM complexes dominated at higher pH in the test solutions.

Psychometric validation of the modified Naranjo algorithm used in homeopathy for chronic cases.

Objectives: The modified Naranjo algorithm assesses the physician assigned cause-effect relationship for homeopathic medicines. It is being adopted in homeopathy researches, but not yet validated systematically. We intended to validate the modified Naranjo algorithm by examining its psychometric properties.

A simple technique to mitigate microplastic pollution and its mobility (via ballast water) in the global ocean.

Ballast water transport is considered as one of the major vectors for dispersal of microplastics around the global oceans. In this commentary, a simple, inexpensive solution has been proposed to reduce microplastic pollution and its mobility via ballast water. A screening chamber (with stainless steel three layered mesh) is proposed to be attached to the existing Ballast Water Treatment Systems (BWTSs) in cargo ships to filter back-flushed sea water from BWTSs.

Biochemical responses of oysters in evaluating environmental quality of tropical Indian estuarine systems.

Impact of varying concentrations and counts of toxic metals and indigenous bacteria on antioxidative defense system in edible oyster, Saccostrea cucullata, collected from four tropical estuarine systems of Goa (west coast of India), are presented in this study. Relatively high abundance of bacteria was estimated from the oysters especially during monsoon season (June-September). Density of total and fecal coliforms were about 24 times higher in the organism than the surrounding water (average TC: 4360 and FC: 3475 MPN 100 ml).

Post depositional changes of sedimentary organic matter influence chromium speciation in continental slope sediments - A case study.

Influences of post depositional changes of sedimentary organic matter (SOM) on chromium (Cr) speciation in continental slope sediments from the east and west coast of India are presented in this study. Average concentrations of total sedimentary Cr (Cr) in the slope areas of both the coasts were not elevated and ranged from 56.8 to 163 mg·kg (avg.

Copper dynamics in a tropical estuarine system during dry season.

This is the first study to comprehend copper (Cu)-dynamics in a monsoon fed Indian estuarine system (the Mandovi estuary from the central west coast of India). Distribution and speciation of Cu in estuarine sediment, pore water, suspended particulate matter (SPM) and water column was used to understand geochemical cycling of Cu in the estuary. Geochemical fractionation study reveals that sedimentary organic carbon (C) was the major hosting phase for non-residual Cu in the sediments.

Geochemical fractionation study in combination with equilibrium based chemical speciation modelling of Cd in finer sediments provide a better description of Cd bioavailability in tropical estuarine systems.

Geochemical fractionation study of cadmium (Cd) in combination with equilibrium based chemical speciation modelling (visual MINTEQ) in finer sediment samples (silt and clay portion), provided a better description of Cd bioavailability for sessile organisms (like oysters) in the Zuari estuary, west coast of India. A substantial fraction of total Cd in the finer sediment samples was present as water soluble, exchangeable and carbonate/bicarbonate forms and showed a strong positive relationship with Cd-bioaccumulation in oysters (Magallana sp.) from the study area.

Evidence for increasing anthropogenic Pb concentrations in Indian shelf sediments during the last century.

India is industrializing rapidly and with this there comes higher releases of contaminants into the environment. Change in Pb deposition over the last century on the eastern (off Andhra Pradesh) and western (off Karnataka) shelves of India was investigated based on the data extracted from two sediment cores covering the past ~114 and ~145 yrs. The variations of the total Pb content, its enrichment factor, and concentrations of non-residual Pb in both the sediment cores document that there was a gradual increase in anthropogenic Pb input into the coastal sediments of India over the last century.

Exposure to Nitrogen Dioxide (NO) from Vehicular Emission Could Increase the COVID-19 Pandemic Fatality in India: A Perspective.

The corona virus-2019 (COVID-19) is ravaging the whole world. Scientists have been trying to acquire more knowledge on different aspects of COVID-19. This study attempts to determine the effects of COVID-19, on a large population, which has already been persistently exposed to various atmospheric pollutants in different parts of India.

Operationally defined mercury (Hg) species can delineate Hg bioaccumulation in mangrove sediment systems: A case study.

This study investigated the linkage between mercury (Hg) speciation in the surficial sediments from a mangrove ecosystem of the Zuari Estuary, west coast of India, with Hg bioaccumulation in gastropods collected from the same area. Multiple operationally defined protocols and methods were used for determination of Hg speciation study in the mangrove sediments. Moderately low concentrations of Hg were observed in the sediments, ranging from 37.

Molecular characteristics of sedimentary organic matter in controlling mercury (Hg) and elemental mercury (Hg) distribution in tropical estuarine sediments.

Sedimentary organic matter (SOM) plays an important role in hosting and reducing Hg in marine/estuarine sediment. This study provides a better understanding on the influence of nature of SOM, in regulating sedimentary mercury (Hg) and elemental mercury (Hg) distribution, and speciation in the Zuari and Mandovi Estuaries that are representative of monsoon fed tropical estuaries, located in the central west coast of India. Salinity of the overlying water column controlled the physical and chemical characteristics of SOM in the estuarine systems.

Snapshot of environmental condition in different tropical estuarine systems by using S. cucullata (an edible oyster) as bio-indicator.

Accumulation of toxic metals and indigenous bacteria in oyster, (Saccostrea cucullata) and their impact on antioxidant enzyme activities in the biological system was studied and used to provide snapshot of environmental condition in different tropical estuarine systems. The sedimentary Cd, Pb, and Hg concentration varied from 0.1 to 1.

Seawater intrusion and resuspension of surface sediment control mercury (Hg) distribution and its bioavailability in water column of a monsoonal estuarine system.

There is limited knowledge regarding seawater intrusion on Hg distribution in monsoon fed tropical estuarine systems during dry season (February to May). This study examined the influence of resuspension of estuarine sediment and intrusion of Hg bound SPM (Hg) (by the tide) from the outside of an estuary in controlling distribution, mobility, and bioavailability of Hg within the estuarine systems during the dry season. This investigation was carried out in the Mandovi estuary, a monsoon fed tropical estuary from the central west coast of India.

Effect of pH on transport and transformation of Cu-sediment complexes in mangrove systems.

Impact of pH variation of overlying water column on transport and transformation of Cu-sediment complexes in the bottom mangrove sediments was investigated by using different metal extraction studies. The total Cu concentration in the studied sediments varied from ~64 ± 1 to 78 ± 2 mg·kg. The sequential extraction study showed that a major part of the sedimentary Cu (85-90% of the total sedimentary Cu) was present within the structure of the sediments with minimum mobility and bioavailability.

Kinetic and equilibrium based fractionation study of Pb in continental shelf sediment of India.

Two independent analytical methods (kinetic and sequential extraction protocols) were used to understand the distribution, stability, and lability of Pb-sediment complexes in Indian continental shelf. The concentrations of sedimentary Pb varied from 12.0±0.

An insight into mercury reduction process by humic substances in aqueous medium under dark condition.

Mercury (Hg) reduction by humic substances (HS) in the aquatic medium under the dark condition is a poorly understood but important process in Hg biogeochemical cycling. In this study, an effort was made to provide a better understanding of Hg(II) reduction by well-characterized humic substances under dark condition. Reduction of Hg(II) by dissolved HS in aquatic systems increases with increasing Hg loading.

Mercury exposure and Alzheimer's disease in India - An imminent threat?

India is an industrial giant with one of the fastest growing major economies in the world. Primary energy consumption in India is third after China and the USA. Greater energy production brings the burden of increasing emissions of mercury (Hg).

Oyster reef restoration in controlling coastal pollution around India: A viewpoint.

Coastal waters receive large amounts of nutrients and pollutants from different point and nonpoint sources through bays and estuaries. Excess supply of nutrients in coastal waters may have detrimental effects, leading to hypoxia and anoxia from eutrophication. Reduction in concentrations of excess nutrients/pollutants in bays/estuarine system is must for healthy coastal ecosystem functioning.

Effects of bottom water dissolved oxygen variability on copper and lead fractionation in the sediments across the oxygen minimum zone, western continental margin of India.

This study describes the effect of varying bottom-water oxygen concentration on geochemical fractionation (operational speciation) of Cu and Pb in the underneath sediments across the oxygen minimum zone (Arabian Sea) in the west coast of India. Both, Cu and Pb were redistributed among the different binding phases of the sediments with changing dissolved oxygen level (from oxic to hypoxic and close to suboxic) in the bottom water. The average lability of Cu-sediment complexes gradually decreased (i.

Linkage between speciation of Cd in mangrove sediment and its bioaccumulation in total soft tissue of oyster from the west coast of India.

This study established a mechanistic linkage between Cd speciation and bioavailability in mangrove system from the west coast of India. High bioaccumulation of Cd was found in the oyster (Crassostrea sp.) even at low Cd loading in the bottom sediment.

Mercury profiles in sediment from the marginal high of Arabian Sea: an indicator of increasing anthropogenic Hg input.

Total Hg distributions and its speciation were determined in two sediment cores collected from the western continental marginal high of India. Total Hg content in the sediment was found to gradually increase (by approximately two times) towards the surface in both the cores. It was found that Hg was preferentially bound to sulfide under anoxic condition.

Distribution and nature of sedimentary organic matter in a tropical estuary: An indicator of human intervention on environment.

Sediment texture controls the spatial distribution of sedimentary organic matter (SOM) in the Vembanad Lake. Influences of marine derived organic matter (OM) on SOM decreased inner-wards in the northern part of the lake. However, SOM from the southern part of the lake was dominated by terrestrial OM.