Little knowledge is available about the potential impact of commercial silver nanoparticles (Ag-NPs) on estuarine microbial communities. The Hugli river estuary, India, is susceptible to heavy metals pollution through boat traffic, and there is the potential for Ag-NP exposure via effluent discharged from ongoing municipal and industrial activities located in close proximity. This study investigated the effects of commercial Ag-NPs on native microbial communities in estuarine sediments collected from five stations, using terminal restriction fragment length polymorphism (T-RFLP) technique. An increase in the number of bacteria in consortium in sediments was observed following exposure to Ag-NPs. In general microbial communities may be resistant in estuarine systems to the antimicrobial effects of commercial Ag-NPs, but key microorganisms, such as Pelobacter propionicus, disappeared following exposure to Ag-NPs. In conclusion, the T-RFLP analysis indicated that Ag-NPs have the potential to shape estuarine sediment bacterial community structure. © 2015 Elsevier Ltd.

B ANTIZAR-LADISLAO

B D BHATTACHARYA

CHAUDHURI S RAY

S K SARKAR

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Marine Pollution Bulletin

Abstract The work first documents detailed account of the seasonal variations of total dissolved trace metals in the coastal regions of Sundarban mangrove wetland (a UNESCO World Heritage Site) using a graphite-furnace atomic absorption spectrophotometer. Considering all three different seasons (premonsoon, monsoon and postmonsoon), the average concentrations and relative variability of the metals exhibited the following sequential order: Mn (223 μg l-1; 261.50 μg l-1) > Cr (39.30 μg l-1; 32.08 μg l-1) > Zn (57.25 μg l-1; 59.78 μg l-1) > Ni (36.23 μg l-1; 43.28 μg l-1) > Cu (33.88 μg l-1; 48.85 μg l-1) > Pb (14.76 μg l-1; 19.76 μg l-1)> Co (20.73 μg l-1; 25.18 μg l-1) > Cd (5.53 μg l-1; 5.68 μg l-1). Concentrations of Cu (maximum 48.85 μg l-1) exceeded the WHO recommended value. The results of the carcinogenic risks for the metals revealed that dermal absorption (CDI<inf>dermal</inf>) of Cr, Pb and Cd might be a matter of concern. Chromium is significantly correlated with majority of the metals indicating their identical behaviour during transport in this coastal environment. Results of canonical correspondence analyses (CCA) confirmed that two study sites in Sundarban, namely Canning and Dhamakhali, clustered at about 85% similarity loading as they suffer from huge load of domestic sewage effluents discharged from the megacity Calcutta resulting maximum concentrations of majority of the trace metals. © 2014 Elsevier Ltd. All rights reserved.

Journal of Cleaner Production

Distribution of dissolved trace metals in coastal regions of Indian Sundarban mangrove wetland: A multivariate approach

The origin and distribution of 19 priority pollutant polycyclic aromatic hydrocarbons (PAHs) in core sediments (&lt;63 μm) from the Sundarban mangrove wetland, northeastern part of Bay of Bengal, India, were investigated by gas-chromatography/mass spectrometry (GC/MS). Sedimentary organic carbon and textural properties were also analyzed in order to assess the role of geochemistry on PAH distribution. ∑ 19PAHs concentration in sediments showed wide variations from 9.4-4222.8 ng/g dry weight, with an overall increase of the high molecular PAHs in the deeper depth profiles. Fluoranthene, chrysene, and pyrene were the most abundant hydrocarbons in sediments and it can be explained by active inputs of soil materials due to frequent strong rainfalls in this tropical climatic zone. A rather exceptional prevalence of high molecular weight PAHs was substantiated: nearly 80% of ∑ 19PAHs include fluoranthene (18-20%), chrysene (14-16%), and pyrene (10-11%). Carcinogenic compounds were present in moderately high (DBA, BkF, BbF) or negligible and low concentrations (BaP, InP) in a majority of cases. The PAH diagnostic ratios indicated that the PAHs in sediment cores were of pyrolytic origin, and that atmospheric deposition and land runoff may serve as the important pathways for PAHs input to the sediments. The total PAH levels were expressed as the benzo (a) pyrene toxicity equivalents (TEQ carc) making this compound a potential marker for PAH pollution. The baseline data can be used for regular ecological monitoring, considering the industrial and agricultural growth around this important estuarine environment. The results indicated that the PAHs in sediments of Sundarban wetland resulted in low to moderate ecosystem risk. © 2012 Copyright Taylor and Francis Group, LLC.

Polycyclic Aromatic Compounds

Distribution and Ecosystem Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Core Sediments of Sundarban Mangrove Wetland, India

The study reports the first assessment for the quantification and speciation of butyltins (BTs) in surface marine sediment samples (0-5 cm) from intertidal mudflats of Sundarban mangrove wetland along with the Hugli (Ganges) river basin, eastern coastal part of India. Concentrations of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) were monitored at 16 stations and present at all study areas, in concentrations in sediments up to 84.2, 26.4 and 48.0 ng g -1 of TBT, DBT and MBT, respectively. Significant correlations were obtained between MBT and DBT (r = 0.62, p = 0.01) and DBT and TBT (r = 0.54, p = 0.03). Calculated BT degradation index (BDI) values indicated recent contamination of BTs at 8 stations, and suggested either no degradation of TBT or very recent degradation at a 4 further stations. Additionally, BDI values also indicated no recent inputs of BTs in 4 stations (only MBT present in one of these stations). High concentrations of BTs, particularly TBT, have the potential to induce ecotoxicological impacts based on levels specified in Australian Sediment Quality Guidelines (SQGs). This study indicated that the majority of the analyzed stations were in the highest range of priority, due to high TBT concentrations. © 2011 Springer Science+Business Media, LLC.

Fulltext

Ecotoxicology

Baseline of butyltin contamination in sediments of Sundarban mangrove wetland and adjacent coastal regions, India

The paper presents the first document regarding concentration, distribution and possible sources of selected trace elements (Cu, Fe, Mn, Zn, Cr, Co, Ni, Pb, Al, B and Ba) in core sediments (&lt; 63 μ particle size) from the lower stretch of Hugli (Ganges) estuary, northeast coast of Bay of Bengal by ICP-AES and EDXRF to evaluate geochemical processes influencing their distribution and possible environmental consequences. The levels of elements showed a wide range of variations in different core depths, in upper and lower intertidal zones as well as among three sampling stations. The most interesting feature of the study is the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 20-28 cm in upper littoral zone of the site located in the extreme downstream stretch of the estuary. Values of organic carbon showed very strong positive correlations with most of the elements as revealed by correlation matrix (r) values. The interelemental relationship revealed the identical behavior of element during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of untreated effluents originating from industrial, agricultural, and aquacultural sources as well as from domestic sewage along with the fishing and boating activities. The resulting compositional dataset was tested by principal component analyses and cluster analyses. Pollution load index (PLI) and index of Geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Pb were typically high for all the stations. The mean concentrations of Zn and to some extent Cu exceeded the Effects Range-Low (ER-L) values in the majority of the cases indicating that there may be some ecotoxicological risk to organisms living in sediments. The concentration of the trace elements reported in this work is useful as baselines for comparison in future sediment quality studies. © 2006 Elsevier Ltd. All rights reserved.

Environment International

Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological significance

The lower tidal stretch of the river Ganges, known as Hugli (ca. 280 km), flows southward before entering the Bay of Bengal forming a vast mangrove-enriched estuarine delta called Sunderbans. Hugli estuary is a typical example of tide-dominated sink for contaminants from multifarious sources. This major important river is subjected to anthropogenic stress due to the socio-economic importance of these areas based on growth of industry, agriculture, aquaculture, port activities, fishing and tourism. The living resources have been degraded recently due to increases in population pressure, pollution and natural resource consumption to the extent of overexploitation. The present paper critically examines the physicochemical characteristics and level of dissolved heavy metals at three ecologically distinct zones along the course of the river - Babughat located in the eastern part of the metropolitan megacity Calcutta (140 km upstream from seaface), Diamond Harbor (70 km upstream from sea face) and Gangasagar positioned at the mouth of the Ganges estuary. Physicochemical characteristics of this partially mixed estuary are largely influenced by the interaction of seawater and discharge of riverine freshwater, annual precipitation and surface runoff. The levels of salinity, total dissolved solids, hardness and conductivity showed an increasing downward trend. Marked increase in biochemical oxygen demand (BOD) values (2.20-5.95 mg/l) was recorded in Babughat whereas correspondingly low values (0.75-2.82 mg/l) were noticed at Gangasagar. This can be attributed mainly due to huge organic load of untreated sewage from the twin city Howrah and Calcutta situated in the east and west of the river. Spatiotemporal distribution of heavy metals reveals a wide range of variations reflecting input of huge anthropogenic inputs associated with a number of physical and chemical processes. Levels of metals registered a seasonal pattern, with an increase during late monsoon months (September-October), a period characterized by low salinity and relatively low pH of the water. Elevated levels of dissolved Hg and Pb were also recorded in Babughat, with values ranging from 0.16 to 0.95 μg/ml and 0.017 to 0.076 μg/ml, respectively, this high values for Hg can be attributed to the discharge from pulp and paper manufacturing units and to atmospheric input and runoff of automobile emission for Pb. It was revealed that the socio-economic development of Calcutta, the most potential economic zone in India situated on the east bank of Hugli river, has had a significant impact on the water quality of this major river. The deterioration of water quality is directly related to nonfunctioning and malfunctioning of wastewater treatment plants and lack of environmental planning and coordination. To restore the ecological stability and economic vitality of this river, the following measures have been suggested: (i) strong vigilance programme is to be undertaken towards installation and maintenance of the wastewater treatment plants to check the flow of persistent contaminants in the river water and (ii) execution of legislation and mass awareness programmes are to be enacted to restore the sound health of the river. The authors urge that environmental education should be used as an effective tool for water resource management dealing with intricate and complex problems in the interaction between nature, technology and human beings. © 2006 Elsevier Ltd. All rights reserved.

Journal	Data powered by TypesetMarine Pollution Bulletin
Publisher	Data powered by TypesetElsevier Ltd
ISSN	0025-326X