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result(s) for
"Mishra, Pravakar"
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Floating microplastic inventories in the southern Beaufort Sea, Arctic Ocean
2023
The microplastics inflow into the Arctic Ocean may increase environmental stress on the Arctic marine ecosystem on the Pacific side, where sea ice has been significantly reduced because of global warming. However, quantitative data on microplastics are very limited in the Beaufort Sea, which is covered by sea ice for most of the year, even in summer. We therefore observed microplastic concentrations over a wide area of the southern Beaufort Sea using a neuston net from 30 August to 10 September 2022 to estimate the total number (particle inventory) and mass (mass inventory) of microplastics in the entire water column. The particle inventory during the sampling period ranged from 937 to 28,081 pieces km −2 (mean ± standard deviation, 7570 ± 7600 pieces km −2 ). The mass inventory of microplastics ranged from 22 to 664 g km −2 (179 ± 180 g km −2 ). Relatively high microplastic inventories (>6500 pieces km −2 ) were observed off Utqiaġvik and the mouth of the Mackenzie River, suggesting that some microplastics originate not only in the Pacific but also in the Arctic. These values indicate that waters in the southern Beaufort Sea is contaminated with microplastics to the same order of magnitude as the Chukchi Sea.
Journal Article
Ecological risk assessment of heavy metals in the coastal sediment in the South-western Bay of Bengal
2023
Dynamic coastal waters are often polluted by chemical pollutants, affecting coastal ecosystems. A total of four scientific coastal cruises up to 10 km offshore from the coastline along the Chennai-Puducherry coast during 2019-20 were conducted. This study examined the spatiotemporal distribution of heavy metals (Cr, Cu, Pb, Cd, Ni, Zn, As, Co, Mn) in the coastal sediments using various geochemical indices, including the Geo-accumulation Index (Igeo), Enrichment Factor (EF), Contamination Factor (CF), and Ecological Risk Index (ERI), to understand the impacts, environmental risks, and pollution status in coastal and marine systems. The heavy metal concentrations of Cr, Cu, Pb, Cd, Ni, Zn, As, Co, and Mn in sediments are 16.48-74.70 μg/g, 2.01-3.78 μg/g, 1.37-17.54 μg/g, 0.20-21.76 μg/g, and 5.73-40.53 μg/g, 4.73-53.54 μg/g, 2.09-28.18 μg/g, 1.80-9.02 μg/g, 70.27-346.22 μg/g, respectively. The I geo results revealed that none of the metals reached up to the contamination level except for Cd and As which showed a slightly contaminated level of the sediment. ERI indicated that coastal sediments are at moderate to high ecological risk from heavy metals. This study will help policymakers make informed decisions for combating or remediating metal pollution to safeguard the coastal environment.
Journal Article
Clinico-epidemiological Study of Viral Acute Encephalitis Syndrome Cases and Comparison to Nonviral Cases in Children from Eastern India
by
Priyadarshini, Lipsa
,
Mishra, Pravakar
,
Das, Rashmi Ranjan
in
Antigens
,
Children
,
Childrens health
2019
Objectives:
The objective is to study the clinico-epidemiological features of viral acute encephalitis syndrome (AES) cases and compare them with nonviral AES cases in children from Eastern India.
Methods:
This prospective observational study was conducted in the department of pediatrics of a tertiary care teaching hospital in Eastern India over 18-month period. Children (6 months to 15 years) with acute onset of fever (≥37.5°C) and a change in mental status (including symptoms such as confusion, disorientation, coma, or inability to talk) and/or new onset of seizures (excluding simple febrile seizures) were included in the study. The main outcome measures were the etiology and proportion attributed to viruses causing AES with clinical correlation.
Results:
Of 834 of clinically suspected AES cases, viral etiology could be confirmed in 136 (16.3%) cases (herpes simplex virus-1 [HSV-I] was most common). The 5-15 years' age group was most commonly affected (boys > girls). More cases occurred from July to November. The presence of rash and Glasgow Coma Scale <8 at admission was significantly higher in viral AES. During hospitalization, development of shock, ventilatory requirement, duration of stay, and mortality was significantly higher in viral AES. On neuroimaging, global cerebral injury was common in HSV, Japanese encephalitis, and varicella-virus AES.
Conclusions:
Viral etiology forms a significant proportion of pediatric AES. Morbidity and mortality are high in viral compared to nonviral AES. Herpes encephalitis (HSV-I) is the most common cause of pediatric AES in Eastern India. Viral AES has poor prognosis compared to nonviral AES.
Journal Article
Monsoonal Influence and Variability of Water Quality, Phytoplankton Biomass in the Tropical Coastal Waters – A Multivariate Statistical Approach
by
Naik, Subrat
,
Mishra, Rajani Kanta
,
Sahu, K. C.
in
Anthropogenic factors
,
Aquatic reptiles
,
Biodiversity
2020
Rushikulya estuary is rich in biodiversity facing significant changes in recent periods due to pollution/anthropogenic impacts from the industries and growing urbanization along the banks of the river. This estuary caters mass nesting of Olive Ridley sea turtles and one of the world's largest rookery in India. In view of the above the present study examined, the seasonal variability of water quality parameters (water temperature, pH, salinity, dissolved oxygen, total suspended matter, inorganic nutrients (NO2-N, NO3-N, NH4-N, PO4-P and SiO4-Si) and the phytopigment i.e. Chlorophyll-a (chl-a) from the seawater samples of three different seasons pre-monsoon, monsoon and post-monsoon.Time-series observations were made at five locations off Rushikulya estuary, Bay of Bengal from March 2011 to February 2013. A wide range of nutrient concentrations except for NO2-N varied from 0.89 - 3.62 µmol/l in the NO3-N, from 1.36 - 6.81 µmol/l in the NH4-N, from 0.66 - 3.45 µmol/l in the PO4- P and from 0.89 -7.97 µmol/l in the SiO4-Si. The highest chl-a (3.72 mg/m3) was recorded during pre-monsoon than monsoon and post monsoon. Factor analysis (FA), showed that three underlying factors, each during pre-monsoon, monsoon and post-monsoon influencing the water quality to the extent of 75.02 %, 67.33 % and 66.37 % respectively. The significant result from a statistical view of non-metric multidimensional scaling (nm-MDS) and cluster analysis (CA) revealed that the chl-a variability was due to the direct influence of nutrients than the physical parameters.Correlation analysis revealed that chl-a was positive correlation with DO, NO2, NO3, PO4 and SiO4, while negative with salinity in pre-monsoon and monsoon. The composite results indicated that the study area is well oxygenated, rich in nutrients and chl-a distribution represents typical upper ocean dynamics and food chain linked to the pristine coastal and ecologically rich ecosystem.
Journal Article
A repercussion of COVID-19 lockdown on water quality along the east coast of India
by
Naik, Subrat
,
Panda, Uma Sankar
,
Mishra, Pravakar
in
Air quality
,
Air quality measurements
,
Aquatic Pollution
2025
The COVID-19 pandemic and subsequent lockdown measures significantly impacted various sectors, including coastal environments. While restrictions led to temporary improvements in air quality, their effects on coastal waters remained understudy. This research conducted four cruises along the east coast of India during pre- and post-COVID-19 lockdown to assess the water quality changes. Results show a significant increase in Chl-a (31.8%), DO (28.1%), and SDD (7.7%), while reductions in NO
3
(34.7%), PO
4
(51.7%), SiO
4
(16.2%), TSM (25.4%), TC (72.3%), and FC (83.3%) were observed. Multivariate analysis identified land-based pollution as the primary source of pollution in coastal waters. Overall, the findings suggest improved coastal water quality during the lockdown. However, for the sustainability of coastal waters, it is proposed that raw sewage, wastewater, and atmospheric fluxes affecting coastal water quality must be regulated.
Journal Article
Characterization and seasonal distribution of microplastics in the nearshore sediments of the south-east coast of India, Bay of Bengal
by
Sambandam, M.
,
Kaviarasan, T.
,
Mishra, Pravakar
in
Abundance
,
Bay of Bengal
,
Characterization
2022
* MPs in the coastal sediment of south-east coast of India are quantified. * High MPs are recorded near river mouths and nearshore regions. * Polyethylene and polypropylene are the major polymers observed. * MPs contamination is higher than the values reported elsewhere.
In view of increasing Microplastics (MPs) contamination in the marine environment and dearth of baseline data, a study was conducted on the abundance, characterization, and seasonal distribution of MPs in the nearshore sediments of the south-east coast of India. Sediment samples ( n = 130) were collected at a distance of 1 km and 10 km from the shore region at varying depths (8-45 m) along the Chennai to Puducherry coast (165 km stretch), representing two seasons, i.e., south-west (July 2019 and July 2020) and north-east (January 2020) monsoons. The average abundance of MPs at the 22 offshore sites along the Chennai to Puducherry coast varied from 9±4.3 to 19±12.9 particles/50 g dry weight, in July 2019 and January 2020, respectively. July 2020 had an average abundance of 10±4.5 particles/50 g dry weight. Spatially, high levels of MPs were found at 1km stations and transects in proximity to the river inlets, and temporally, the north-east month recorded the maximum concentration. The dominant morphotype was the filament, and the major polymers were polyethylene and polypropylene. Scanning Electron Microscope (SEM) images revealed the surface irregularity and degradation of MPs due to weathering. The study highlights that high sediment contamination by MPs occurs during heavy rainfall and accumulates closer to river inlets. Eventually, this study suggests that appropriate management of plastic wastes on the landside will reduce MP contamination in the marine environment.
Journal Article
Abundance, distribution and characterization of microplastics in Tropical River Estuary, South East Coast of India
2024
Rivers play pivotal role in transporting plastic litter into the ocean. The present study aimed to estimate microplastics (MPs) in Palar River (PR), that receives waste inputs of agricultural, industries, fishing, and domestic origin. Water and sediment samples were collected during low tide, at seven locations from inner check dam to mouth region. Highest concentration of MPs in water are observed at PR-6 (28.01 × 104 particles.km−2) and the lowest was recorded at PR-4 (2.6 × 104 particles.km−2). In sediment, highest count was detected at PR-1 (8.8 × 102 ± 226 particles.kg−1 d.w) and the lowest was recorded in PR-6 (2.5 × 102 ± 14 particles.kg−1d.w). MPs distribution in water is more in the outer mouth (PR-6) in comparison to inner region (PR-4). Fibres were dominating morphotype of MPs, comprised of 79.4% in water and 89.8% in sediment samples. According to size classification, the majority of particles (41.02% in water and 56.1% in sediment) were in the size range of 1 μm to 1000 μm. Characterization of MPs through Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy revealed that High Density Polyethylene (HDPE) is the dominant polymer indicating the use of plastic fishing nets and ropes along with the outfall from nearby industries may be the main contributor to the microplastic pollution in the river.
Journal Article
Microplastic Contamination in Kollidam River Estuary, East Coast of India: A Comparative Study Across Inner, Outer and Mangrove Estuarine Regions
by
Balaji, V Aswath
,
Saichand, V
,
Nagalakshmi, R
in
Brackishwater environment
,
Color
,
Comparative analysis
2024
Increased mismanaged plastic has led to widespread microplastic (MPs) contamination in the marine environment. Our study investigates MPs across the inner, outer, and mangrove regions of the Kollidam River estuary on the east coast of India. Surface water and sediment samples at 18 locations were analysed for size, shape, colour, and polymer type. The average MP abundance in surface water and sediment was 2.42 particles. m−3and 1580 ± 705 particles. kg−1d.w. respectively. The predominant polymer types observed were PP (40%), PE (26%), and PAc (24%). Medium-sized particles (1–2.5 mm) are more in surface water (44%), and small-sized (0.01–1 mm) particles dominate in sediment samples (50%). The most common MP shapes were fibres and fragments, with transparent MPs being the most frequently observed colour. The results highlight that the mangrove region acts as a potential sink for microplastic pollution.
Journal Article