ResearchPad - Water Science and Technology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Landscape metrics as predictors of hydrologic connectivity between Coastal Plain forested wetlands and streams]]> https://www.researchpad.co/product?articleinfo=5b4c25fc463d7e045e4d94ba

Abstract

Geographically isolated wetlands, those entirely surrounded by uplands, provide numerous landscape‐scale ecological functions, many of which are dependent on the degree to which they are hydrologically connected to nearby waters. There is a growing need for field‐validated, landscape‐scale approaches for classifying wetlands on the basis of their expected degree of hydrologic connectivity with stream networks. This study quantified seasonal variability in surface hydrologic connectivity (SHC) patterns between forested Delmarva bay wetland complexes and perennial/intermittent streams at 23 sites over a full‐water year (2014–2015). Field data were used to develop metrics to predict SHC using hypothesized landscape drivers of connectivity duration and timing. Connection duration was most strongly related to the number and area of wetlands within wetland complexes as well as the channel width of the temporary stream connecting the wetland complex to a perennial/intermittent stream. Timing of SHC onset was related to the topographic wetness index and drainage density within the catchment. Stepwise regression modelling found that landscape metrics could be used to predict SHC duration as a function of wetland complex catchment area, wetland area, wetland number, and soil available water storage (adj‐R 2 = 0.74, p < .0001). Results may be applicable to assessments of forested depressional wetlands elsewhere in the U.S. Mid‐Atlantic and Southeastern Coastal Plain, where climate, landscapes, and hydrological inputs and losses are expected to be similar to the study area.

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<![CDATA[The Impact of Diesel Oil Pollution on the Hydrophobicity and CO2 Efflux of Forest Soils]]> https://www.researchpad.co/product?articleinfo=5bf7a3b2d5eed0c484eab493

The contamination of soil with petroleum products is a major environmental problem. Petroleum products are common soil contaminants as a result of human activities, and they are causing substantial changes in the biological (particularly microbiological) processes, chemical composition, structure and physical properties of soil. The main objective of this study was to assess the impact of soil moisture on CO2 efflux from diesel-contaminated albic podzol soils. Two contamination treatments (3000 and 9000 mg of diesel oil per kg of soil) were prepared for four horizons from two forest study sites with different initial levels of soil water repellency. CO2 emissions were measured using a portable infrared gas analyser (LCpro+, ADC BioScientific, UK) while the soil samples were drying under laboratory conditions (from saturation to air-dry). The assessment of soil water repellency was performed using the water drop penetration time test. An analysis of variance (ANVOA) was conducted for the CO2 efflux data. The obtained results show that CO2 efflux from diesel-contaminated soils is higher than efflux from uncontaminated soils. The initially water-repellent soils were found to have a bigger CO2 efflux. The non-linear relationship between soil moisture content and CO2 efflux only existed for the upper soil horizons, while for deeper soil horizons, the efflux is practically independent of soil moisture content. The contamination of soil by diesel leads to increased soil water repellency.

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<![CDATA[Performance of National Maps of Watershed Integrity at Watershed Scales]]> https://www.researchpad.co/product?articleinfo=5b6db344463d7e5199b309cb

Watershed integrity, the capacity of a watershed to support and maintain ecological processes essential to the sustainability of services provided to society, can be influenced by a range of landscape and in-stream factors. Ecological response data from four intensively monitored case study watersheds exhibiting a range of environmental conditions and landscape characteristics across the United States were used to evaluate the performance of a national level Index of Watershed Integrity (IWI) at regional and local watershed scales. Using Pearson’s correlation coefficient (r), and Spearman’s rank correlation coefficient (rs), response variables displayed highly significant relationships and were significantly correlated with IWI and ICI (Index of Catchment Integrity) values at all watersheds. Nitrogen concentration and flux-related watershed response metrics exhibited significantly strong negative correlations across case study watersheds, with absolute correlations (|r|) ranging from 0.48 to 0.97 for IWI values, and 0.31 to 0.96 for ICI values. Nitrogen-stable isotope ratios measured in chironomids and periphyton from streams and benthic organic matter from lake sediments also demonstrated strong negative correlations with IWI values, with |r| ranging from 0.47 to 0.92, and 0.35 to 0.89 for correlations with ICI values. This evaluation of the performance of national watershed and catchment integrity metrics and their strong relationship with site level responses provides weight-of-evidence support for their use in state, local and regionally focused applications.

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<![CDATA[Environmental Safety of the Use of Major Surfactant Classes in North America]]> https://www.researchpad.co/product?articleinfo=5ad7d681463d7e12f460f25b

This paper brings together over 250 published and unpublished studies on the environmental properties, fate, and toxicity of the four major, high-volume surfactant classes and relevant feedstocks. The surfactants and feedstocks covered include alcohol sulfate or alcohol sulfate (AS), alcohol ethoxysulfate (AES), linear alkylbenzene sulfonate (LAS), alcohol ethoxylate (AE), and long-chain alcohol (LCOH). These chemicals are used in a wide range of personal care and cleaning products. To date, this is the most comprehensive report on these substance's chemical structures, use, and volume information, physical/chemical properties, environmental fate properties such as biodegradation and sorption, monitoring studies through sewers, wastewater treatment plants and eventual release to the environment, aquatic and sediment toxicity, and bioaccumulation information. These data are used to illustrate the process for conducting both prospective and retrospective risk assessments for large-volume chemicals and categories of chemicals with wide dispersive use. Prospective risk assessments of AS, AES, AE, LAS, and LCOH demonstrate that these substances, although used in very high volume and widely released to the aquatic environment, have no adverse impact on the aquatic or sediment environments at current levels of use. The retrospective risk assessments of these same substances have clearly demonstrated that the conclusions of the prospective risk assessments are valid and confirm that these substances do not pose a risk to the aquatic or sediment environments. This paper also highlights the many years of research that the surfactant and cleaning products industry has supported, as part of their environmental sustainability commitment, to improve environmental tools, approaches, and develop innovative methods appropriate to address environmental properties of personal care and cleaning product chemicals, many of which have become approved international standard methods.

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<![CDATA[The Dublin SURGE Project: geochemical baseline for heavy metals in topsoils and spatial correlation with historical industry in Dublin, Ireland]]> https://www.researchpad.co/product?articleinfo=5ad2df0f463d7e4d2af6bc90

The Dublin SURGE (Soil Urban Geochemistry) Project is Dublin’s first baseline survey of heavy metals and persistent organic pollutants in topsoils and is part of a Europe-wide initiative to map urban geochemical baselines in ten cities. 1,058 samples were collected as part of a stratified random sampling programme in the greater Dublin area to give an overview of baseline conditions in the city. Samples were analysed for 31 inorganic elements including heavy metals. Analysis of results indicates that the concentrations of lead, copper, zinc and mercury are strongly influenced by human activities, with elevated concentrations in the city docklands, inner city and heavy industry areas. Sources of heavy metals in these areas may include historical industry, coal burning, re-use of contaminated soil, modern traffic and leaded paint and petrol. Concentrations of other inorganic elements in topsoil show patterns which are strongly related to regional bedrock parent material. The spatial distributions of heavy metals, in particular Pb and As, are explored in detail with respect to regional geology and the influence of historical industry on soil quality. Exploratory data, geostatistical and correlation analyses suggest that the concentrations of heavy metals tend to increase as the intensity of historical industrial activity increases. In particular, drinks production, power generation, oil/gas/coal, metals and textile historical industries appear to be the contamination source for several heavy metals. The data provide a geochemical baseline relevant to the protection of human health, compliance with environmental legislation, land use planning and urban regeneration.

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<![CDATA[Heterologous ectoine production in Escherichia coli: By-passing the metabolic bottle-neck]]> https://www.researchpad.co/product?articleinfo=5989db3aab0ee8fa60bd494d

Transcription of the ectoine biosynthesis genes ectA, ectB and ectC from Marinococcus halophilus in recombinant Escherichia coli DH5α is probably initiated from three individual σ70A-dependent promoter sequences, upstream of each gene. Consequently, mRNA-fragments containing the single genes and combinations of the genes ectA and ectB or ectB and ectC, respectively, could be detected by Northern blot analysis. Under the control of its own regulatory promoter region (ectUp) a seemingly osmoregulated ectoine production was observed. In addition, aspartate kinases were identified as the main limiting factor for ectoine production in recombinant E. coli DH5α. Co-expression of the ectoine biosynthesis genes and of the gene of the feedback-resistant aspartate kinase from Corynebacterium glutamicum MH20-22B (lysC) led to markedly increased production of ectoine in E. coli DH5α, resulting in cytoplasmic ectoine concentrations comparable to those reached via ectoine accumulation from the medium.

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<![CDATA[Transcriptional responses to biologically relevant doses of UV-B radiation in the model archaeon, Halobacterium sp. NRC-1]]> https://www.researchpad.co/product?articleinfo=5989dac8ab0ee8fa60bb3557

Background

Most studies of the transcriptional response to UV radiation in living cells have used UV doses that are much higher than those encountered in the natural environment, and most focus on short-wave UV (UV-C) at 254 nm, a wavelength that never reaches the Earth's surface. We have studied the transcriptional response of the sunlight-tolerant model archaeon, Halobacterium sp. NRC-1, to low doses of mid-wave UV (UV-B) to assess its response to UV radiation that is likely to be more biologically relevant.

Results

Halobacterium NRC-1 cells were irradiated with UV-B at doses equivalent to 30 J/m2 and 5 J/m2 of UV-C. Transcriptional profiling showed that only 11 genes were up-regulated 1.5-fold or more by both UV-B doses. The most strongly up-regulated gene was radA1 (vng2473), the archaeal homologue of RAD51/recA recombinase. The others included arj1 (vng779) (recJ-like exonuclease), top6A (vng884) and top6B (vng885) (coding for Topoisomerase VI subunits), and nrdJ (vng1644) (which encodes a subunit of ribonucleotide reductase). We have found that four of the consistently UV-B up-regulated genes, radA1 (vng2473), vng17, top6B (vng885) and vng280, share a common 11-base pair motif in their promoter region, TTTCACTTTCA. Similar sequences were found in radA promoters in other halophilic archaea, as well as in the radA promoter of Methanospirillum hungatei. We analysed the transcriptional response of a repair-deficient ΔuvrA (vng2636) ΔuvrC (vng2381) double-deletion mutant and found common themes between it and the response in repair proficient cells.

Conclusion

Our results show a core set of genes is consistently up-regulated after exposure to UV-B light at low, biologically relevant doses. Eleven genes were up-regulated, in wild-type cells, after two UV-B doses (comparable to UV-C doses of 30 J/m2 and 5 J/m2), and only four genes were up-regulated by all doses of UV-B and UV-C that we have used in this work and previously. These results suggest that high doses of UV-C radiation do not necessarily provide a good model for the natural response to environmental UV. We have found an 11-base pair motif upstream of the TATA box in four of the UV-B up-regulated genes and suggest that this motif is the binding site for a transcriptional regulator involved in their response to UV damage in this model archaeon.

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<![CDATA[Acidophilic haloarchaeal strains are isolated from various solar salts]]> https://www.researchpad.co/product?articleinfo=5989d9e4ab0ee8fa60b6a876

Haloarchaeal strains require high concentrations of NaCl for their growth, with optimum concentrations of 10–30%. They display a wide variety of morphology and physiology including pH range for growth. Many strains grow at neutral to slightly alkaline pH, and some only at alkaline pH. However, no strain has been reported to grow only in acidic pH conditions within the family Halobacteriaceae.

In this study, we isolated many halophiles capable of growth in a 20% NaCl medium adjusted to pH 4.5 from 28 commercially available salts. They showed growth at pH 4.0 to 6.5, depending slightly on the magnesium content. The most acidophilic strain MH1-52-1 isolated from an imported solar salt (pH of saturated solution was 9.0) was non-pigmented and extremely halophilic. It was only capable of growing at pH 4.2–4.8 with an optimum at pH 4.4 in a medium with 0.1% magnesium chloride, and at pH 4.0–6.0 (optimum at pH 4.0) in a medium with 5.0% magnesium. The 16S rRNA and DNA-dependent RNA polymerase subunit B' gene sequences demonstrated clearly that the strain MH1-52-1 represents a new genus in the family Halobacteriaceae.

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<![CDATA[Effect of benthic boundary layer transport on the productivity of Mono Lake, California]]> https://www.researchpad.co/product?articleinfo=5989dacdab0ee8fa60bb4d94

The significance of the transport of nutrient-rich hypolimnetic water via the benthic boundary layer (BBL) to the productivity of Mono Lake was studied using a coupled hydrodynamic and ecological model validated against field data. The coupled model enabled us to differentiate between the role of biotic components and hydrodynamic forcing on the internal recycling of nutrients necessary to sustain primary productivity. A 4-year period (1991–1994) was simulated in which recycled nutrients from zooplankton excretion and bacterially-mediated mineralization exceeded sediment fluxes as the dominant source for primary productivity. Model outputs indicated that BBL transport was responsible for a 53% increase in the flux of hypolimnetic ammonium to the photic zone during stratification with an increase in primary production of 6% and secondary production of 5%. Although the estimated impact of BBL transport on the productivity of Mono Lake was not large, significant nutrient fluxes were simulated during periods when BBL transport was most active.

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<![CDATA[Unravelling the adaptation responses to osmotic and temperature stress in Chromohalobacter salexigens, a bacterium with broad salinity tolerance]]> https://www.researchpad.co/product?articleinfo=5989da02ab0ee8fa60b746cb

Chromohalobacter salexigens, a Gammaproteobacterium belonging to the family Halomonadaceae, shows a broad salinity range for growth. Osmoprotection is achieved by the accumulation of compatible solutes either by transport (betaine, choline) or synthesis (mainly ectoine and hydroxyectoine). Ectoines can play additional roles as nutrients and, in the case of hydroxyectoine, in thermotolerance. A supplementary solute, trehalose, not present in cells grown at 37°C, is accumulated at higher temperatures, suggesting its involvement in the response to heat stress. Trehalose is also accumulated at 37°C in ectoine-deficient mutants, indicating that ectoines suppress trehalose synthesis in the wild-type strain. The genes for ectoine (ectABC) and hydroxyectoine (ectD, ectE) production are arranged in three different clusters within the C. salexigens chromosome. In order to cope with changing environment, C. salexigens regulates its cytoplasmic pool of ectoines by a number of mechanisms that we have started to elucidate. This is a highly complex process because (i) hydroxyectoine can be synthesized by other enzymes different to EctD (ii) ectoines can be catabolized to serve as nutrients, (iii) the involvement of several transcriptional regulators (σS, σ32, Fur, EctR) and hence different signal transduction pathways, and (iv) the existence of post-trancriptional control mechanisms. In this review we summarize our present knowledge on the physiology and genetics of the processes allowing C. salexigens to cope with osmotic stress and high temperature, with emphasis on the transcriptional regulation.

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<![CDATA[A retrospective approach to assess human health risks associated with growing air pollution in urbanized area of Thar Desert, western Rajasthan, India]]> https://www.researchpad.co/product?articleinfo=5989db06ab0ee8fa60bc8806

Air pollution has been a matter of great concern globally because of the associated health risks to individuals. The situation is getting worse in developing countries with more urbanization, industrialization and more importantly the rapidly growing population posing a threat to human life in the form of pulmonary, cardiovascular, carcinogenic or asthmatic diseases by accumulating toxic pollutants, harmful gases, metals, hydrocarbons etc.

Objective

The present study was undertaken to assess the magnitude of ambient air pollutants and their human health risks like respiratory ailments, infectious diseases, cardiovascular diseases and cancer using a Retrospective Approach of Bart Ostra.

Methodology

The parameters PM2.5, PM10, NOx, SO2, NH3 and O3 were monitored at all selected study sites monitored through a high volume sampler (APM 451 Envirotech, Envirotech Instruments Pvt. Ltd., New Delhi, India). Retrospective Approach was used for assessment of risk factors and disease burden of respiratory and cardiopulmonary health problems.

Results

Environmental burden of disease showed that the problem of health related to air pollution is a main concern particularly in the growing cities of India. High to critical level of air pollution including PM10, PM2.5, NOx, SO2, NH3 and O3 was observed in all seasons at traffic intersections and commercial sites. The respiratory infections (25% incidence in population exposed to indoor smoke problems) and a prevalence of asthma/COPD (4.4%) in households exposed to high vehicular pollution along with signs of coronary artery/heart disease and/or hypertension and cancers (37.9-52.2%), were reported requiring preventive measures.

Conclusion

The study reflects a great concern for the mankind with the need of having streamline ways to limit air pollution and emphasize upon efficiently determining the risk of illness upon exposure to air pollution.

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<![CDATA[Response surface analysis of photocatalytic degradation of methyl tert-butyl ether by core/shell Fe3O4/ZnO nanoparticles]]> https://www.researchpad.co/product?articleinfo=5989da86ab0ee8fa60b9c3ca

The degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous solution of coated ZnO onto magnetite nanoparticale based on an advanced photocatalytic oxidation process. The photocatalysts were synthesized by coating of ZnO onto magnetite using precipitation method. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). Besides, specific surface area was also determined by BET method. The four effective factors including pH of the reaction mixture, Fe3O4/ZnO magnetic nanoparticles concentration, initial MTBE concentration and molar ratio of [H2O2]/ [MTBE] were optimized using response surface modeling (RSM). Using the four-factor-three-level Box–Behnken design, 29 runs were designed considering the effective ranges of the influential factors. The optimized values for the operational parameters under the respective constraints were obtained at PH of 7.2, Fe3O4/ZnO concentration of 1.78 g/L, initial MTBE concentration of 89.14 mg/L and [H2O2]/ [MTBE] molar ratio of 2.33. Moreover, kinetics of MTBE degradation was determined under optimum condition. The study about core/shell magnetic nanoparticles (MNPs) recycling were also carried out and after about four times, the percentage of the photocatalytic degradation was about 70%.

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<![CDATA[Linearised and non-linearised isotherm models optimization analysis by error functions and statistical means]]> https://www.researchpad.co/product?articleinfo=5989dad5ab0ee8fa60bb78ba

In adsorption study, to describe sorption process and evaluation of best-fitting isotherm model is a key analysis to investigate the theoretical hypothesis. Hence, numerous statistically analysis have been extensively used to estimate validity of the experimental equilibrium adsorption values with the predicted equilibrium values. Several statistical error analysis were carried out. In the present study, the following statistical analysis were carried out to evaluate the adsorption isotherm model fitness, like the Pearson correlation, the coefficient of determination and the Chi-square test, have been used. The ANOVA test was carried out for evaluating significance of various error functions and also coefficient of dispersion were evaluated for linearised and non-linearised models. The adsorption of phenol onto natural soil (Local name Kalathur soil) was carried out, in batch mode at 30 ± 20 C. For estimating the isotherm parameters, to get a holistic view of the analysis the models were compared between linear and non-linear isotherm models. The result reveled that, among above mentioned error functions and statistical functions were designed to determine the best fitting isotherm.

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<![CDATA[Greenhouse Gases Life Cycle Assessment (GHGLCA) as a decision support tool for municipal solid waste management in Iran]]> https://www.researchpad.co/product?articleinfo=5989dad6ab0ee8fa60bb7f4b

Background

One of the most problems in developing countries is the integrated waste management and the effects on Greenhouse Gases (GHG) emission, Life Cycle Assessment (LCA) is used in this paper as a decision supporting tool in planning Municipal Solid Waste (MSW) managements.

Methods

In this paper the EPA’s Waste Reduction Model (WARM) that provide GHG emission factors for waste stream components that are based on life Cycle Inventory (LCI) framework were used and The MSW management methods comprised in seven scenarios.

Results

The amount of GHG which was generated from Iran’s waste sector estimated about 17836079 Metric Tons of Carbon dioxide Equivalents (MT CO2e) in this study. The lowest amount of GHG was generated by LFG capture system with energy recovery (557635 MT CO2e), while Incineration of materials being sent to landfill (1756823 MT CO2e), Landfill Gas (LFG) capture system with flaring (2929150 MT CO2e) and Improved source reduction and recycling (4780278 MT CO2e) emitted fewer GHG than the other scenarios. Lowest levels of gross energy consumption occur in source reduction with recycling and composting (-89356240 Mega British Thermal Unit, M BTU), recycling and composting (-86772060 M BTU) as well as Improved source reduction with recycling and composting (-54794888 M BTU).

Conclusions

It appears that recycling and composting each offer significant GHG emissions and energy consumption reductions (scenarios 4, 5 and 6). Upon of the GHG emission and energy consumption results concluded that improved source reduction and recycling scenario has been the Balanced and appropriate technology for handling the solid waste streams in municipalities.

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<![CDATA[Bioremediation of p-Nitrophenol by Pseudomonas putida 1274 strain]]> https://www.researchpad.co/product?articleinfo=5989dac1ab0ee8fa60bb0eba

Background

p-Nitrophenol (PNP) occurs as contaminants of industrial effluents and it is the most important environmental pollutant and causes significant health and environmental risks, because it is toxic to many living organisms. Nevertheless, the information regarding PNP degradation pathways and their enzymes remain limited.

Objective

To evaluate the efficacy of the Pseudomonas Putida 1274 for removal of PNP.

Methods

P. putida MTCC 1274 was obtained from MTCC Chandigarh, India and cultured in the minimal medium in the presence of PNP. PNP degradation efficiency was compared under different pH and temperature ranges. The degraded product was isolated and analyzed with different chromatographic and spectroscopic techniques.

Results

P. putida 1274 shows good growth and PNP degradation at 37°C in neutral pH. Acidic and alkali pH retarded the growth of P. putida as well as the PNP degradation. On the basis of specialized techniques, hydroquinone was identified as major degraded product. The pathway was identified for the biodegradation of PNP. It involved initial removal of the nitrate group and formation of hydroquinone as one of the intermediates.

Conclusion

Our results suggested that P. putida 1274 strain would be a suitable aspirant for bioremediation of nitro-aromatic compounds contaminated sites in the environment.

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<![CDATA[Removal of tetracycline from wastewater using pumice stone: equilibrium, kinetic and thermodynamic studies]]> https://www.researchpad.co/product?articleinfo=5989daddab0ee8fa60bba7cc

In this study, pumice stone was used for the removal of tetracyline (TC) from aqueous solutions. It was characterized by XRD, FT-IR, SEM and BET analyses. Cation exchange capacity of pumice stone was found to be 9.9 meq/100 g. Effect of various parameters such as solution pH (2–11), adsorbent dosage (0.5-10 g/L), contact time (2.5-120 min), initial TC concentration (5–300 mg/L) and temperature (20–50°C) on TC adsorption onto pumice was investigated. Also the adsorption of TC on pumice stone was studied as a function of Na+ and Cu2+ cations changing pH from 2 to 11 using batch experiments. The best removal efficiency performance was exhibited at adsorbent dosage 10 g/L, pH 3, contact time 120 min. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models were applied to the equilibrium data. The result has shown that the adsorption was favorable, physicochemical in nature and agrees well with Langmuir and Freundlich models. The maximum Langmuir adsorption capacity was found to be 20.02 mg/g. The adsorption behavior of TC on pumices stone was fitted well in the pseudo-second order kinetics model. Thermodynamic parameters calculated from the adsorption data at different temperature showed that the adsorption reaction was feasible, spontaneous and exothermic.

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<![CDATA[Ambient x-ray pollution assessment at inspection gates of airports- a case study of Mehrabad and Imam Khomeini Airports in Iran]]> https://www.researchpad.co/product?articleinfo=5989da0aab0ee8fa60b7757f

Background

As a well-known, physical carcinogen, ambient X-ray pollution assessment would be of great importance in today’s modern world. Accordingly, the present study was done to measure the exposure level of ambient X-ray at inspection gates of two airports in Iran. According to which, the X-ray was measured at different points of the inspection gates including closed and opened Curtain, as well as seating place of operators beside the X-ray inspection systems. The recorded data were then analyzed by “sign” and t-tests.

Results

The total average exposure level of the measured x-ray was 2.68 ± 0.73 μsv.h-1. The measured x-ray exposure level was 2.07 ± 0.61 (μsv.h-1) released from RAPISCAN X-ray inspection system and 3.3 ± 1.34 (μsv.h-1) emitted from HEIMANN X-ray inspection system. Comparison of average x-ray doses of the systems in both airports showed that the minimum and maximum exposure levels were recorded at 1(m) far from the devices and at the entrance of the devices, respectively.

Conclusions

The exposure levels at all measurement points were lower than the occupational exposure limit. This reveals the fact that the exposed operators are not probably at risk of adverse health effects.

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<![CDATA[Harmful metals concentration in sediments and fishes of biologically important estuary, Bay of Bengal]]> https://www.researchpad.co/product?articleinfo=5989da6cab0ee8fa60b933b9

Study on the accumulation level of heavy metals was conducted on sediment and fishes from estuaries of Bay of Bengal. Heavy metals were determined by using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and the results were compared to permissible limits of WHO/USEPA. The accumulation patterns of Fe and Cd were found predominantly in all samples tested when correlated with other metals. It was found that the concentration of metals such as Cd (3.90 ± 0.25 μg/g), Cr (0.44 ± 0.05 μg/g), Ni (0.33 ± 0.01 μg/g), and Mn (1.1 ± 0.11 μg/g) were exceeding the permissible limit, whereas Fe, Co, Pb, and Zn were found within the limit of WHO/USEPA at station 1. In station 2, Cd (16.5 ± 0.4 μg/g), Mn (0.67 ± 0.11 μg/g), and Cr (0.80 ± 0.01 μg/g) were exceeding the permissible limit, whereas Fe, Co, Pb, Ni, and Zn were found within the limit. This study emphasizes that Cd and Mn levels in both stations, are far higher than the acceptable values set by WHO/USEPA and may therefore present human health hazards. It is therefore mandatory to carry out extensive research to evaluate the possible environmental risk factors in the vicinity of both estuaries with respect to heavy metals.

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<![CDATA[Development of pilot scale nanofiltration system for yeast industry wastewater treatment]]> https://www.researchpad.co/product?articleinfo=5989daebab0ee8fa60bbf32e

The treatment of the yeast industry wastewater was investigated by nanofiltration (NF) membrane process on a pilot scale. Two wastewaters were used as feed: (i) dilute wastewater with COD 2000 mg/L and (ii) concentrate wastewater with COD 8000 mg/L. The permeate flux, COD retention, color and electrical conductivity (EC) removal were evaluated in relation to trans-membrane pressure and long-term filtration. A linear growth in permeate flux was found with increasing in trans-membrane pressure for wastewaters. In addition, the COD retention, color and EC removal increased with trans-membrane pressure enhancement. The results obtained from the long-term nanofiltration of dilute wastewater indicated that the permeate flux decreased from 2300 L/day to 1250 L/day and COD retention increased from 86% to 92%. The quality of the permeate in term of COD is lower than the discharge standard in river (200 mg/L). Thus, this process is useful for treatment of wastewaters produced by yeast industry.

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<![CDATA[Oily wastewaters treatment using Pseudomonas sp. isolated from the compost fertilizer]]> https://www.researchpad.co/product?articleinfo=5989da75ab0ee8fa60b964a7

Background

Discharging the oily wastewater in the environment causes serious problems, because of the oil compounds and organic materials presence. Applying biological methods using the lipase enzyme producer microorganisms can be an appropriate choice for treatment of these wastewaters. The aim of this study is to treat those oil wastewaters having high concentration of oil by applying lipase enzyme producer bacteria.

Materials and methods

Oil concentration measurement was conducted using the standard method of gravimetric and the wastewater under study was synthetically made and contained olive, canola and sunflower oil. The strain used in this study was Pseudomonas strain isolated from compost fertilizer. The oil under study had concentration of 1.5 to 22 g/l.

Results

The oil removal amount in concentrations lower than 8.4 g/l was over 95 ± 1.5%. Increase of the oil's concentration to 22 g/l decreases the amount of removal in retention time of 44 hours to 85 ± 2.5%. The best yield of removing this strain in retention time of 44 hours and temperature of 30°C was achieved using Ammonium Nitrate as the nitrogen resource which yield was about 95 percent.

Conclusion

The findings of the research showed that Pseudomonas bacteria isolated from the compost fertilizer can degrade high concentration oils.

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