Rate of sediment accumulation and historic metal contamination in a tidewater glacier fjord, Svalbard.

The sedimentation rates in Arctic fjords are influenced by the changes in the glacial inputs. The recent studies have indicated the retreat of glaciers due to climate change and subsequent increase in melt water outflow with high content of debris. The debris may contain natural and anthropogenically originated contaminants. The present study analysed the sedimentation rate in inner Kongsfjorden, Ny-Ålesund, Svalbard using 210Pb/210Po dating technique. The sedimentation rate ranged between 0.22 and 0.37 cm/year during the last 112 years. The average sedimentation rate obtained was 0.28 cm/y. The rate has been increased during the last 20 years and it might be due to the increased influx of glacial melt water containing debris. Metals and other elements showed an increasing trend towards the surface and observed high deposition rate since 1970s, indicating influence of industrial emissions and it can be a potential threat to Arctic biota.

Multi-element detection in sea water using preconcentration procedure and EDXRF technique.

A method was optimized for detecting trace elements in sea water using Energy dispersive X-ray fluorescence (EDXRF) technique. Sea water samples were pre-concentrated using ammonium pyrrolidinedithiocarbamate (APDC) as chelating agent and methyl isobutyl ketone (MIBK) as organic phase. The preconcentrated samples were dried to form thin films on mylar substrate and analysed using EDXRF spectrometer. The multi-element standard samples prepared in synthetic sea water were used for EDXRF instrument calibration. The instrument was calibrated for 11 elements namely As, Cd, Co, Cr, Fe, Ga, Pb, Se, Sc, V and Zn using linear regression method for concentration up to 200 ppb. The detection limits achieved for As, Cd, Co, Cr, Fe, Ga, Pb, Se, Sc, V and Zn were 13, 70, 5.1, 36, 15, 36, 23, 11, 20, 13 and 40 ppb respectively. The optimized method was used for determination of elements in sea water collected from the Thane creek, Mumbai, India. The results were checked for accuracy by comparing it with inductively coupled plasma atomic emission spectroscopy (ICP AES) technique. The comparison showed the discrepancy of results to be insignificant at 95% confidence level.

Determination of Traces of Pb, Cu and Cd in Seawater around Thane Creek by Anodic Stripping Voltammetry Method.

Trace metals (Pb, Cu and Cd) in seawater samples were pre-concentrated for the simultaneous quantitative determination using solvent extraction procedure in the presence of ammonium pyrrolidine dithiocarbamate (APDC) as complexing agent and methyl isobutyl ketone (MIBK) as organic phase and acid exchange back - extraction followed by its determination by Differential Pulse Anodic Stripping Voltammetry (DPASV). Concentrations of Pb, Cu and Cd vary from 3.0 to 9.44 ng/mL, 12.7 to 28.6 ng/mL and 0.31 to 1.21 ng/mL respectively in seawater samples collected from different locations across Thane Creek area, Mumbai, India. Pb, Cu, Cd concentration were observed to be higher in the eastern side of the Thane Creek as it is covered by various industries.

Distribution of PAHs in different compartment of creek ecosystem: Ecotoxicological concern and human health risk.

We report levels of polycyclic aromatic hydrocarbons in sediment, seawater, fish and crab samples from Thane creek, India. Concentrations of sixteen USEPA PAH in sediments varies from 874 to 1925ngg-1, dry weight (dw) in winter, between 219-495ngg-1 in summer. In seawater Σ16 PAHs concentration during winter was recorded 706±193ngL-1, and during summer 337±79ngL-1. Total concentrations of PAHs in consumable portion of lizard fish, bombay duck and crab were found 156.8±18 and 122±24.5ngg-1, 117.4±17.65ngg-1 and 95.8±16.2ngg-1, 348±94.5 and 95.62±31.9ngg-1 wet weight (ww) in summer and winter respectively. PAHs concentration were compared with sediments quality guidelines viz. ERL-ERM, TEL-PEL indexes for finding ecotoxicological risk on marine organism. The ILCR values were above public screening criteria for carcinogens.

Leaching Behavior of Selected Trace and Toxic Metals in Coal Fly Ash Samples Collected from Two Thermal Power Plants, India.

Studies on leaching behavior of metals associated with coal fly ash (FA) are of great concern because of possible contamination of the aquatic environment. In the present study, leaching behavior of metals (As, Se, Cr, Pb, V, Zn, etc.) in two different FA samples (FA1 and FA2) was investigated at various pH (2-12), temperatures of leachate solution and using TCLP. At pH 2, the highest leaching was observed for Fe (21.6 and 32.8 µg/g), whereas at pH 12, Arsenic was found to have the highest leaching (1.5 and 2.4 µg/g) in FA1 and FA2. Leachate solution temperature showed a positive effect on the metal's leachability. In TCLP, most of the metal's leachability was observed to be higher than that of batch leaching tests. The present study suggests that, leaching of As and Se from FA samples can moderately affect ground/surface water quality at the study locations.

Polonium in size fractionated mainstream cigarette smoke, predicted deposition and associated internal radiation dose.

In this study, size fractionated mass and 210Po activity concentrations in mainstream cigarette smoke (MCS) were monitored for three popular cigarette brands. Size segregated collection of MCS was carried out using a cascade type impactor, while mass and 210Po activity concentration were analyzed gravimetrically and alpha spectrometry (following the radiochemical separation) respectively. Multiple-Path Particle Dosimetry (MPPD V2.11) model is used for prediction of deposition fraction calculations for the MCS deposition in different compartment of human respiratory tract. The activity concentration of 210Po is founds 10.56 ± 2.46 mBq per cigarette for the tested cigarette brands. 210Po size distribution indicates most of this associates with fine fraction (Dp < 2.23 µm) of cigarette smoke. The committed annual effective dose to smokers (smoking on an average 20 cigarette a day), considering the 210Po and 210Pb concentrations (assuming it is in secular equilibrium with 210Po) in MCS, was estimated between 0.22 and 0.40 mSv, with mean value of 0.30 mSv for tested cigarette brands. Considering the risk factor of fatal cancer due to radiation exposure of lung (exposure time of 30 years); the average collective estimated fatal cancer risk is estimated as 1.5 × 10-4 due to 210Po and 210Pb exposure to smokers.

Distribution and estrogenic potential of endocrine disrupting chemicals (EDCs) in estuarine sediments from Mumbai, India.

Endocrine disrupting chemicals (EDCs) are responsible for inappropriate development and they alter the hormonal and homeostatic systems of organism. Phthalates (PAEs), bisphenol A (BPA) and other EDCs were monitored in surface sediments at different stations across Thane Creek, India. Analysis of PAEs was carried out using GC-MS technique, while BPA and other EDCs were analyzing on UPLC-PDA instrument. Di-n-butyl phthalate (DBP) had the highest concentration among all fourteen analyzed phthalates ranges between 0.13 and 0.4 mg kg(-1); and was detectable in all sediment samples. Strong correlation (r = 0.95, p < 0.01) was observed between total organic carbon (TOC, %) and total PAEs. BPA was also detected in all samples; average BPA concentration varies from 16.3 to 35.79 µg kg(-1) with mean value 25.15 µg kg(-1) dry weight of sediment. Synthetic EDCs such as 4-para-nonylphenol (NP) and 4-tert-octylphenol (OP) were also analyzed; and their average concentrations were founds to be 356.5 and 176 µg kg(-1), respectively. Estrone (E1), 17ß-estradiol (E2), and 17α-ethinylestradiol (EE2) were the main contributors to the overall estradiol equivalent concentration (EEQs) in sediment, their average total percentage contributions is more than 90 %.

Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash.

Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for (210)Po using alpha spectrometry and for natural U, (226)Ra, (232)Th and (40)K by an HPGe γ-ray spectrometer. (210)Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of (238)U, (226)Ra, (232)Th, (40)K in fly ash were 38.5-101 (78.1), 60-105.7 (79), 20-125 (61.7) and 43.6-200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. (210)Po showed the largest size dependence with its concentration favoring the smaller particle size while (232)Th showed least size dependence. (238)U and (226)Ra showed behavior intermediate to that of (210)Po and (232)Th. Also the correlation between sulfur content of the feed coal and activity of (210)Po was investigated. Increased sulfur content in feed coal enhanced enrichment of (210)Po in ash.

Estimation of Kd of lead and (210)Po in 11 soils from India.

The fate of contaminant transport is often estimated using the distribution (partition) coefficient, Kd. It is a measure of sorption of contaminants to soil. As Kd is element, soil type and ground water dependent, chemical characterization of soil and ground water of the particular site is essential. In this study, soil and ground water samples from different locations around India were collected. The soil samples were physically characterized and pH, CaCO3, cation exchange capacity (CEC), organic matter and organic carbon were determined. Equilibration time for lead and (210)Po were estimated with respect to contact time and were found to be 28 and 72 h respectively. The Kd of lead varied from 6700 to 31,000 L/kg with a geometric mean of 15,200 L/kg, and for (210)Po from 1400 to 8700 L/kg with a geometric mean of 3700 L/kg.

Elemental characterization of coal, fly ash, and bottom ash using an energy dispersive X-ray fluorescence technique.

A total of 18 elements viz. Si, Al, Fe, Ca, Mg, K, Na, Sr, V, Zn, Mn, Cr, Cu, Pb, Ni, Co, As and Cd were analyzed in coal, fly ash and bottom ash samples collected across India using an EDXRF technique. Various indices such as element enrichment ratio, enrichment factor (with respect to crustal average) and mineral composition were calculated. Around 95% of mass was reconstructed using the concentration of elements in this study for fly and bottom ash.

Seasonal variation of black carbon in fine particulate matter (PM2.5) at the tropical coastal city of Mumbai, India.

Black Carbon (BC) is a pollutant species primarily emitted from the combustion of fossil fuels. BC levels, associated with fine particulate matter (PM2.5), were monitored from January 2009 to December 2010 at an urban industrial area in Mumbai to study the seasonal and temporal variations and its contribution to fine particulate matter. Air particulate samples were collected in two size fractions, fine particulate matter (PM2.5) and coarse particulate matter (PM2.5-10), using a Gent air sampler. During the study period, arithmetic means of PM2.5 and PM2.5-10 were found to be 30.4 and 68.2 µg/m(3), respectively. The average value of BC in fine particulate matter was 4.0 µg/m(3), with a range of 1.0-9.4 µg/m(3). Studies carried out using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicated the contribution of BC from the northern and central part of India during days of high BC levels.

Depth profile of major and trace elements in estuarine core sediment using the EDXRF technique.

Distribution and enrichment of elements in sediment are influenced by their texture, mineralogical composition, and physical transport. The vertical concentration profiles of sixteen elements in core sediment samples, namely Na, Mg, Al, K, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sr, and Pb were measured using the energy dispersive X-ray fluorescence (EDXRF) technique. To check the anthropogenic input various indices (enrichment factor, contamination factor, index of geoaccumulation and pollution load index) were calculated and compared.

Estimation of distribution coefficient of natural radionuclides in soil around uranium mines and its effect with ionic strength of water.

The distribution coefficient, K(d) in soil is an important parameter to predict the migration of contaminants. In this study, uranium (U) and its decay products thorium (Th), radium (Ra), bismuth (Bi), lead (Pb) and polonium (Po), which may contaminate the soil and ground water around uranium mining areas, have been considered. Soil and ground water samples were collected from a proposed uranium mining site in India. The soil samples were characterised for different parameters affecting the K(d) values. The batch sorption method was employed to measure the K(d) of different radionuclides. The important factors affecting the batch method for K(d) estimation were identified and optimised. The variation of K(d) was observed with different ionic strength water samples. Results showed high K(d) values for Th(IV), Po(IV) and Pb(II) (log K(d) ∼4) and low K(d) (log K(d) ∼2-3) for U(VI), Ra(II) and Bi(III) in all three types of water with different ionic strength.

Chemical characterization of precipitation at a coastal site in Trombay, Mumbai, India.

Precipitation is the best scavenger for the particulates and dissolved gaseous pollutants present in the atmosphere. The chemical composition of precipitation is dominated by a number of in-cloud and below-cloud scavenging processes. The present study is aimed at analyzing the chemical composition of rainwater in the relatively less industrialized part of Mumbai. The pH of rainwater in this region ranges from 4.8 to 6.4. The percentage contributions of ions were calculated and the major contributing ions were calcium (28%), chloride (23%), sodium (18%), sulfate (14%), magnesium (11%), ammonium (4%), potassium (1%), and nitrate (1%). The correlation coefficient is highest for Na and Cl (r(2) = 0.99), giving a clear indication of contribution from sea salt. Sulfate and nitrate ions also show a very good correlation (r(2) = 0.90), which may be due to their coemission from fossil fuel combustion. Acidification caused by these ions is neutralized by Ca, Mg, and NH(4) ions. The neutralization effect due to these ions is validated by calculating the neutralization factor (NF). The NF values are in the order Ca > Mg > NH(4). The major source contributors for the ions in precipitation are sea salt (Na, Cl, and K) and fossil fuel combustion (SO(4) and NO(3)). These assumptions are supported by the values of wet-only ratio, enrichment factor, and percent sea salt fraction.

Organochlorine pesticides in Avicennia marina from the Mumbai mangroves, India.

This paper examines the concentration levels of organochlorine pesticides (OCPs) such as hexachlorocyclohexane (HCH) (alpha, beta and gamma), Aldrin, Endosulfan (alpha, beta), DDE, DDD, and DDT in the leaf, root and sediment part of Avicennia marina, a dominantly distributed mangrove species in Mumbai. The overall pattern of accumulation of OCPs was observed as sigmaHCH> sigmaDDT> sigmaEndosulfan>Aldrin. The occurrence of alphaHCH was found to be frequent in all the samples. The leaf and root samples showed better uptake of organochlorine pesticides whereas lower concentration levels of OCPs was observed in case of sediment samples. The mean concentration of OCPs was observed highest in case of root samples. This study indicated towards the capability of A. marina in bioaccumulation of the OCPs. The present data will serve as the baseline against which future study of OCPs uptake in the mangrove plant species may be assessed.

Estimation of 210Po and its risk to human beings due to consumption of marine species at Mumbai, India.

(210)Po was estimated in the edible muscle and soft tissue of 15 different marine species (fish, crab, prawn and bivalve) collected from Trans-Thane Creek area (Trombay) and Thane. Potential risks associated with consumption of marine organisms due to (210)Po collected from this particular area to human beings were assessed. Estimation of (210)Po was carried out using radiochemical separation and alpha spectrometric technique. The concentration of (210)Po was found to vary from 0.18 to 10.9 Bqkg(-1) wet wt in different biota species and maximum concentrations were observed in bivalves. The variations in (210)Po concentration in different species are mainly due to difference in metabolism and feeding habits. The daily intake and individual dose of (210)Po to human beings through biota consumption was calculated and found to be 31.89 mBqd(-1) and 19.44 microSvyr(-1), respectively. An assessment of the risk on human beings due to consumption of marine organism was undertaken using carcinogenic slope factor for (210)Po. 5th, 50th and 95th percentile of life time risk was calculated to be 9.74E-06, 4.39E-05 and 2.12E-04, respectively.

Vertical distribution of polychlorinated biphenyl congeners in sediment core from Thane Creek area of Mumbai, India.

In recent years there has been a growing concern all over the globe about the marine pollution due to persistent organic pollutants. Sediments, which is an important component of marine environment can serve as sorbent or concentrator for various persistent organic pollutants including Polychlorinated Biphenyls (PCBs). Transport and fate of PCB congeners in sediment depends on their physicochemical characteristics. In this study, the depth profile of accumulated PCBs in Thane Creek sediments of Mumbai, India, was studied. The sediment core samples were collected using a gravity corer, processed and analysed for different PCB congeners. Analysis of PCBs in the sediment samples were carried out using gas chromatography system equipped with electron capture detector. The study on vertical distribution of PCBs in sediment could reflect the geochemical history including changes due to anthropogenic releases into the system. The surface segment shows the downward trend for these compounds, indicating slow phase out of PCBs after ban. The concentration and composition of different homologues varies at different depth. An attempt has also been made to find out the various sources of PCBs which could have contributed to these compounds by performing factor analysis over the observed concentrations of the PCB compounds in the core sediment.

Trace metals and organometals in selected marine species and preliminary risk assessment to human beings in Thane Creek area, Mumbai.

Trace metals and organometals were estimated in different types of marine organisms (fish, bivalve, crab and prawn) collected from the Trans-Thane Creek area, Mumbai. Thane Creek area is considered as most polluted area due to industrial discharges. Potential risks associated with consumption of marine organisms collected from this particular area to human beings were assessed. Concentrations of ten trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn) in the edible part of marine organisms were analysed by atomic absorption spectrometer and differential pulse anodic stripping voltametric technique. Methyl mercury and tributyl tin were estimated using gas chromatograph-mass spectrometer in combination with solid phase micro extraction (SPME). An assessment of the risk on human beings due to consumption of marine organism was undertaken using toxic reference benchmark, namely the reference dose (RfD). The hazard index (HI), sum of hazard quotients calculated for all the pollutant showed that the risks from consumption of fish and marine organisms as a whole were generally low and are within safe limits.

Distribution and fate of persistent organochlorine pesticides in coastal marine environment of Mumbai.

Multi-compartment monitoring of residue levels of OCPs in coastal marine environment of Mumbai has been studied. The concentration of total HCHs in seawater varied from 0.16 to 15.92 ng/L and concentrations of total DDT varied from 3.01 to 33.21 ng/L. The total HCH concentration in the sediment samples was in the range of 3.8 to 16.2 ng/g. Gamma-HCH contributed almost 55% to the total HCH. In sediment samples the DDT has higher mean concentration in comparison to its metabolite DDE and DDD. The concentration of total HCHs in different marine species varied from 0.87 to 33.73 ng/g and concentrations of total DDT varied from 0.38 to 34.1 ng/g. The variation in the beta-HCH in different compartments is not significant and this could be due to the high persistence and metabolically inactive nature of this isomer. The alpha-HCH is found to be more dominant in fish samples whereas the gamma-HCH is major contributor in the sediment samples.

Exchange of polycyclic aromatic hydrocarbons across the air-water interface at the creek adjoining Mumbai harbour, India.

Concentration levels of polycyclic aromatic hydrocarbons (PAHs) have been determined in air and water in order to estimate the magnitude and direction of gas flux across the air-water interface at the creek adjoining the Mumbai harbour, India. The range of total PAHs was found to be 4.1-30.4 ng/m3 in air and 84.3-377.5 ng/l in seawater, respectively. The lower molecular weight PAHs revealed positive values of the fluxes indicating the tendency for transfer of these contaminants from water to air. In contrast, fluxes of less volatile compounds like benzo(k)fluoranthene and benzo(a)pyrene were always from the atmosphere into the surface water of the creek at all locations and sampling periods. While the fugacity ratio ranged from 0.12 to 6.97, it was found greater than 1 for the lower molecular weight PAHs and less than 1 for higher molecular weight PAHs. The present study suggests the active transfer of lower molecular weight dissolved PAHs into the atmosphere due to volatilization and deposition of higher molecular weight gas-phase PAHs into the surface water.