Impact of water quality on chlorine demand of corroding copper

EPA Pesticide Factsheets

Copper is widely used in drinking water premise plumbing system materials. In buildings such ashospitals, large and complicated plumbing networks make it difficult to maintain good water quality.Sustaining safe disinfectant residuals throughout a building to protect against waterborne pathogenssuch as Legionella is particularly challenging since copper and other reactive distribution system materialscan exert considerable demands. The objective of this work was to evaluate the impact of pH andorthophosphate on the consumption of free chlorine associated with corroding copper pipes over time. Acopper test-loop pilot system was used to control test conditions and systematically meet the studyobjectives. Chlorine consumption trends attributed to abiotic reactions with copper over time weredifferent for each pH condition tested, and the total amount of chlorine consumed over the test runsincreased with increasing pH. Orthophosphate eliminated chlorine consumption trends with elapsedtime (i.e., chlorine demand was consistent across entire test runs). Orthophosphate also greatly reducedthe total amount of chlorine consumed over the test runs. Interestingly, the total amount of chlorineconsumed and the consumption rate were not pH dependent when orthophosphate was present. Thefindings reflect the complex and competing reactions at the copper pipe wall including corrosion,oxidation of Cu(I) minerals and ions, and possible oxidation of Cu(II) minerals, and the change in

Kinetics of chlorination of zirconia in mixture with petroleum coke by chlorine gas

NASA Astrophysics Data System (ADS)

Jena, P. K.; Brocchi, E. A.; Reis, M. L. Dos

1999-06-01

Studies on the kinetics of carbothermic chlorination of zirconium dioxide in gaseous chlorine were carried out with petroleum coke fines in powder form. The amounts of ZrO2 chlorinated were found to be directly proportional to the time of chlorination in the temperature range studied (973 to 1273 K). The activation energy values for chlorination of ZrO2, in mixture with petroleum coke, was found to be 18.3 kJ/mole. The influence of particle size of petroleum coke on the chlorination of ZrO2 (-38 + 25 µm) was studied, and it was found that the rate of chlorination increased up to the size range of -75 to +53 µm, and the size finer than this produced negligible increase. The amount of petroleum coke in the mixture above 17.41 pct in excess of the stoichiometry resulted in very little increase in the rate. The effect of the partial pressure of chlorine ( pCl2) on the rate of chlorination was found to obey the following relationship, derived from the Langmuir adsorption isotherm: v = {k \\cdot K \\cdot pCl_2 }/{l + K \\cdot pCl_2 } where v is the amount of ZrO2 (g/min) reacted, k is the rate constant, and K is the equilibrium constant for adsorption of two chlorine atoms (obtained from the dissociation of a molecule of Cl2 at the carbon surface) on the surface of ZrO2. By plotting 1/ v vs 1/ pCl2, a straight-line relationship with an intercept in x-axis is obtained, further supporting the preceding equation. The dissociation of the adsorbed complex, Cl … ZrO2 … Cl to ZrCl2 and O2 is suggested to be the rate-controlling step. Subsequently, the less stable ZrCl2 combines with Cl2 to form ZrCl4 and the oxygen combines with C to form CO and CO2.

Infrared identification of the σ-complex of Cl-C6H6 in the reaction of chlorine atom and benzene in solid para-hydrogen.

PubMed

Bahou, Mohammed; Witek, Henryk; Lee, Yuan-Pern

2013-02-21

The reaction of a chlorine atom with benzene (C6H6) is important in organic chemistry, especially in site-selective chlorination reactions, but its product has been a subject of debate for five decades. Previous experimental and theoretical studies provide no concrete conclusion on whether the product is a π- or σ-form of the Cl-C6H6 complex. We took advantage of the diminished cage effect of para-hydrogen (p-H2) to produce Cl in situ to react with C6H6 (or C6D6) upon photolysis of a Cl2/C6H6 (or C6D6)/p-H2 matrix at 3.2 K. The infrared spectrum, showing intense lines at 1430.5, 833.6, 719.8, 617.0, and 577.4 cm(−1), and several weaker ones for Cl-C6H6, and the deuterium shifts of observed new lines unambiguously indicate that the product is a 6-chlorocyclohexadienyl radical, i.e., the σ-complex of Cl-C6H6. Observation of the σ-complex rather than the π-complex indicates that the σ-complex is more stable in solid p-H2 at 3.2 K. The spectral information is crucial for further investigations of the Cl + C6H6 reaction either in the gaseous or solution phase.

INTEGRATED DISINFECTION BY-PRODUCTS (DBP) MIXTURES RESEARCH: GENE EXPRESSION ALTERATIONS IN PRIMARY RAT HEPATOCYTE CULTURES EXPOSED TO DBP MIXTURES FORMED BY CHLORINATION AND OZONATION/POSTCHLORINATION

EPA Science Inventory

What is the study?
This study was designed to provide data on the in vitro toxicity of water concentrates containing complex mixtures of DBPs. Rat hepatocytes in primary culture were exposed for 24 hr to full strength, 1:10 or 1:20 dilutions of chlorination or ozonation/chl...

Modeling the Onset of Phase Separation in CaO-SiO2-CaCl2 Chlorine-Containing Silicate Glasses.

PubMed

Swansbury, Laura A; Mountjoy, Gavin; Chen, Xiaojing; Karpukhina, Natalia; Hill, Robert

2017-06-08

The addition of chlorine into a bioactive glass composition is expected to reduce its abrasiveness and increase its bioactivity, which is important for dental applications such as toothpastes. There is a lack of information and understanding regarding the structural role of chlorine in chlorine-containing bioactive silicate glasses. This has prompted classical core-shell model molecular dynamics simulations of (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses to be performed, where x ranges from x = 0.0 to 43.1 mol % CaCl 2 . These ternary glasses are advantageous for a fundamental study because they do not have additional network formers (e.g., phosphorus pentoxide) or modifiers (e.g., sodium) typically found in bioactive glass compositions. The (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses were seen to become phase-separated around the x = 16.1 mol % CaCl 2 composition, and chlorine predominantly coordinated with calcium. These findings provide a solid foundation for further computational modeling work on more complex chlorine-containing bioactive glass compositions.

Ionic Fluorine Chemistry.

DTIC Science & Technology

SOLID ROCKET OXIDIZERS, *LIQUID ROCKET OXIDIZERS, CHLORATES, FLUORIDES, ACETONES, CHLORINE COMPOUNDS, NITROSO COMPOUNDS, *HALOGEN COMPOUNDS, ADDITION REACTIONS, CESIUM COMPOUNDS, CHLORIDES, COMPLEX COMPOUNDS

Quantifying Short-Chain Chlorinated Paraffin Congener Groups.

PubMed

Yuan, Bo; Bogdal, Christian; Berger, Urs; MacLeod, Matthew; Gebbink, Wouter A; Alsberg, Tomas; de Wit, Cynthia A

2017-09-19

Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are referred to as a "congener group" C n Cl m . Recently, we resolved individual C n Cl m by mathematically deconvolving soft ionization high-resolution mass spectra of SCCP mixtures. Here we extend the method to quantifying C n Cl m by introducing C n Cl m specific response factors (RFs) that are calculated from 17 SCCP chain-length standards with a single carbon chain length and variable chlorination level. The signal pattern of each standard is measured on APCI-QTOF-MS. RFs of each C n Cl m are obtained by pairwise optimization of the normal distribution's fit to the signal patterns of the 17 chain-length standards. The method was verified by quantifying SCCP technical mixtures and spiked environmental samples with accuracies of 82-123% and 76-109%, respectively. The absolute differences between calculated and manufacturer-reported chlorination degrees were -0.9 to 1.0%Cl for SCCP mixtures of 49-71%Cl. The quantification method has been replicated with ECNI magnetic sector MS and ECNI-Q-Orbitrap-MS. C n Cl m concentrations determined with the three instruments were highly correlated (R 2 > 0.90) with each other.

Polychlorinated biphenyl congener distributions in burbot: evidence for a latitude effect

USGS Publications Warehouse

Stapanian, Martin A.; Madenjian, Charles P.; Cott, Peter A.; Rediske, Richard R.; O'Keefe, James P.

2014-01-01

We compared the distributions of the congeners of polychlorinated biphenyls (PCBs) detected in whole-body samples of burbot (Lota lota) from Great Slave Lake and Lake Erie. Total PCB concentrations in Great Slave Lake burbot were about 1/60 of the concentrations in Lake Erie burbot. Burbot from Great Slave Lake contained a higher proportion of lower-chlorinated (2-6 chlorines) congeners than did burbot from Lake Erie; the reverse occurred for more highly chlorinated (7-9 chlorines) congeners. Hexachloro congeners, followed by pentachloro congeners, dominated the proportions of total PCB in burbot from both lakes. There were no differences between sexes in whole-body samples or between gonad and somatic tissues in the proportions of the 39 congeners and three sets of co-eluters detected in burbot from Great Slave Lake. In contrast, there were distinct sex differences in congener distributions for older burbot from Lake Erie. Our results generally supported a prediction of higher proportions of lower-chlorinated PCB homologs in organisms in remote polar areas. However, the latitudinal effect on PCB congener distribution may be more complex than that portrayed in previous studies.

Impact of vegetation and ecosystems on chlorine(-36) cycling and its modeling: from simplified approaches towards more complex biogeochemical tools

NASA Astrophysics Data System (ADS)

Thiry, Yves; Redon, Paul-Olivier; Gustafsson, Malin; Marang, Laura; Bastviken, David

2013-04-01

Chlorine is very soluble at a global scale with chloride (Cl-), the dominating form. Because of its high mobility, chlorine is usually perceived as a good conservative tracer in hydrological studies and by analogy as little reactive in biosphere. Since 36Cl can be considered to have the same behaviour than stable Cl, a good knowledge of chlorine distribution between compartments of terrestrial ecosystems is sufficient to calibrate a specific activity model which supposes rapid dilution of 36Cl within the large pool of stable Cl and isotopic equilibrium between compartments. By assuming 36Cl redistribution similar to that of stable Cl at steady-state, specific activity models are simplified interesting tools for regulatory purposes in environmental safety assessment, especially in case of potential long term chronic contamination of agricultural food chain (IAEA, 2010). In many other more complex scenarios (accidental acute release, intermediate time frame, and contrasted natural ecosystems), new information and tools are necessary for improving (radio-)ecological realism, which entails a non-conservative behavior of chlorine. Indeed observed dynamics of chlorine in terrestrial ecosystems is far from a simple equilibrium notably because of natural processes of organic matter (SOM) chlorination mainly occurring in surface soils (Öberg, 1998) and mediated by microbial activities on a large extent (Bastviken et al. 2007). Our recent studies have strengthened the view that an organic cycle for chlorine should now be recognized, in addition to its inorganic cycle. Major results showed that: organochlorine (Clorg) formation occurs in all type of soils and ecosystems (culture, pasture, forest), leading to an average fraction of the total Cl pool in soil of about 80 % (Redon et al., 2012), chlorination in more organic soils over time leads to a larger Clorg pool and in turn to a possible high internal supply of inorganic chlorine (Clin) upon dechlorination. (Gustafsson et al., 2012), average Cl residence time in forest soils calculated for Clin and Clorg together was 5-fold higher that the residence time estimated for Clin alone (Redon et al., 2011), locally, Cl amount taken up by certain vegetation types can be larger than annual atmospheric deposits, the Cl in excess being recycled mainly by throughfall (Thiry, 2010), root uptake and chlorine transformation rates in soils are essential to calibrate dynamic compartment models since those processes control the persistence of chlorine in the whole system but data are still deficient for different land uses (Van den Hoof & Thiry, 2012). References: Bastviken, D., Thomsen, F., Svensson, T., Karlsson, S., Sandén, P., Shaw, G., Matucha, M., and Öberg, G. (2007). Chloride retention in forest soil by microbial uptake and by natural chlorination of organic matter. Geochim. Cosmochim. Acta, 71: 3182-3192. Gustavsson, M., Karlsson, S.,Öberg, G.,Sandén, P.,Svensson, T.,Valinia, S.,Thiry, Y. and Bastviken, D. (2012). Organic matter chlorination rates in different boreal soils: the role of soil organic matter content. Environmental Science & Technology, 46 (3): 1504-1510 Thiry, Y., 2010. Contribution à l'étude du cycle biogéochimique du chlore en écosystème forestier: cas d'un peuplement de pin sylvestre. Rapport Andra n° ENV.NT.ASTR.10.0068. IAEA (2010). Handbook of parameter values for the prediction of radionuclide transfer to humans in terrestrial and freshwater environments. Technical Report Series n° 472, Vienna, Austria. Öberg, G. (1998). Chloride and organic chlorine in soil. Acta hydrochimica et hydrobiologica, 26 (3): 137-144. Redon, P-O., Abdelouas, A., Bastviken, D., Cecchini, S. Nicolas, M. and Thiry, Y. (2011). Chloride and organic chlorine in forest soils: storage, residence times, and influence of ecological conditions. Environmental Science & Technology, 45: 7202-7208. Redon, P-O., Jolivet, C., Saby, N., Abdelouas, A.and Thiry, Y. (2012). Occurrence of natural organic chlorine in soils for different land uses. Biogeochemistry (In press), doi: 10.1007/s10533-012-9771-7. Van den Hoof, C. and Thiry, Y. (2012). Modelling of the natural chlorine cycling in a coniferous stand: implications for chlorine-36 behaviour in a contaminated forest environment. Journal of Environmental Radioactivity., 107: 56-67.

Concentration, chlorination, and chemical analysis of drinking water for disinfection byproduct mixtures health effects research: U.S. EPA's Four Lab Study.

PubMed

Pressman, Jonathan G; Richardson, Susan D; Speth, Thomas F; Miltner, Richard J; Narotsky, Michael G; Hunter, E Sidney; Rice, Glenn E; Teuschler, Linda K; McDonald, Anthony; Parvez, Shahid; Krasner, Stuart W; Weinberg, Howard S; McKague, A Bruce; Parrett, Christopher J; Bodin, Nathalie; Chinn, Russell; Lee, Chih-Fen T; Simmons, Jane Ellen

2010-10-01

The U.S. Environmental Protection Agency's "Four Lab Study" involved participation of researchers from four national Laboratories and Centers of the Office of Research and Development along with collaborators from the water industry and academia. The study evaluated toxicological effects of complex disinfection byproduct (DBP) mixtures, with an emphasis on reproductive and developmental effects that have been associated with DBP exposures in some human epidemiologic studies. This paper describes a new procedure for producing chlorinated drinking water concentrate for animal toxicology experiments, comprehensive identification of >100 DBPs, and quantification of 75 priority and regulated DBPs. In the research reported herein, complex mixtures of DBPs were produced by concentrating a natural source water with reverse osmosis membranes, followed by addition of bromide and treatment with chlorine. By concentrating natural organic matter in the source water first and disinfecting with chlorine afterward, DBPs (including volatiles and semivolatiles) were formed and maintained in a water matrix suitable for animal studies. DBP levels in the chlorinated concentrate compared well to those from EPA's Information Collection Rule (ICR) and a nationwide study of priority unregulated DBPs when normalized by total organic carbon (TOC). DBPs were relatively stable over the course of the animal studies (125 days) with multiple chlorination events (every 5-14 days), and a significant portion of total organic halogen was accounted for through a comprehensive identification approach. DBPs quantified included regulated DBPs, priority unregulated DBPs, and additional DBPs targeted by the ICR. Many DBPs are reported for the first time, including previously undetected and unreported haloacids and haloamides. The new concentration procedure not only produced a concentrated drinking water suitable for animal experiments, but also provided a greater TOC concentration factor (136×), enhancing the detection of trace DBPs that are often below detection using conventional approaches.

Diiridium Bimetallic Complexes Function as a Redox Switch To Directly Split Carbonate into Carbon Monoxide and Oxygen.

PubMed

Chen, Tsun-Ren; Wu, Fang-Siou; Lee, Hsiu-Pen; Chen, Kelvin H-C

2016-03-23

A pair of diiridium bimetallic complexes exhibit a special type of oxidation-reduction reaction that could directly split carbonate into carbon monoxide and molecular oxygen via a low-energy pathway needing no sacrificial reagent. One of the bimetallic complexes, Ir(III)(μ-Cl)2Ir(III), can catch carbonato group from carbonate and reduce it to CO. The second complex, the rare bimetallic complex Ir(IV)(μ-oxo)2Ir(IV), can react with chlorine to release O2 by the oxidation of oxygen ions with synergistic oxidative effect of iridium ions and chlorine atoms. The activation energy needed for the key reaction is quite low (∼20 kJ/mol), which is far less than the dissociation energy of the C═O bond in CO2 (∼750 kJ/mol). These diiridium bimetallic complexes could be applied as a redox switch to split carbonate or combined with well-known processes in the chemical industry to build up a catalytic system to directly split CO2 into CO and O2.

[Determination of Chloride Salt Solution by NIR Spectroscopy].

PubMed

Zhang, Bin; Chen, Jian-hong; Jiao, Ming-xing

2015-07-01

Determination of chloride salt solution by near infrared spectrum plays a very important role in Biomedicine. The near infrared spectrum analysis of Sodium chloride, potassium chloride, calcium chloride aqueous solution shows that the concentration change of chloride salt can affect hydrogen bond, resulting in the variation of near infrared spectrum of water. The temperature influence on NIR spectrum has been decreased by choosing reasonable wavelength range and the wavelength where the temperature effects are zero (isosbestic point). Chlorine salt prediction model was established based on partial least squares method and used for predicting the concentration of the chlorine ion. The impact on near infrared spectrum of the cation ionic radius, the number of ionic charge, the complex effect of ionic in water has also discussed in this article and the reason of every factor are analysed. Experimental results show that the temperature and concentration will affect the near-infrared spectrum of the solution, It is found that the effect of temperature plays the dominant role at low concentrations of chlorine salt; rather, the ionic dominates at high concentration. Chloride complexes are formed in aqueous solution, It has an effect on hydrogen bond of water combining with the cations in chlorine salt solution, Comparing different chloride solutions at the same concentration, the destruction effects of chloride complexes and catnions on the hydrogen bond of water increases in the sequences: CaCl2 >NaCl>KC. The modeling result shows that the determination coefficients (R2) = 99.97%, the root mean square error of cross validation (RM- SECV) = 4.51, and the residual prediction deviation (RPD) = 62.7, it meets the daily requirements of biochemical detection accuracy.

Separation and screening of short-chain chlorinated paraffins in environmental samples using comprehensive two-dimensional gas chromatography with micro electron capture detection.

PubMed

Xia, Dan; Gao, Lirong; Zhu, Shuai; Zheng, Minghui

2014-11-01

Short-chain chlorinated paraffins (SCCPs) are highly complex technical mixtures with thousands of isomers and numerous homologs. They are classified as priority candidate persistent organic pollutants under the Stockholm Convention for their persistence, bioaccumulation, and toxicity. Analyzing SCCPs is challenging because of the complexity of the mixtures. Chromatograms of SCCPs acquired using one-dimensional (1D) gas chromatography (GC) contain a large characteristic "peak" with a broad and unresolved profile. Comprehensive two-dimensional GC (GC×GC) shows excellent potential for separating complex mixtures. In this study, GC×GC coupled with micro electron capture detection (μECD) was used to separate and screen SCCPs. The chromatographic parameters, including the GC column types, oven temperature program, and modulation period, were systematically optimized. The SCCP congeners were separated into groups using a DM-1 column connected to a BPX-50 column. The SCCP congeners in technical mixtures were separated according to the number of chlorine substituents for a given carbon chain length and according to the number of carbon atoms plus chlorine atoms for different carbon chain lengths. A fish tissue sample was analyzed to illustrate the feasibility of the GC×GC-μECD method in analyzing biological samples. Over 1,500 compounds were identified in the fish extract, significantly more than were identified using 1D GC. The detection limits for five selected SCCP congeners were between 1 and 5 pg/L using the GC×GC method, and these were significantly lower than those achieved using 1D GC. This method is a good choice for analysis of SCCPs in environmental samples, exhibiting good separation and good sensitivity.

Infrared identification of the {sigma}-complex of Cl-C{sub 6}H{sub 6} in the reaction of chlorine atom and benzene in solid para-hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahou, Mohammed; Witek, Henryk; Lee, Yuan-Pern

2013-02-21

The reaction of a chlorine atom with benzene (C{sub 6}H{sub 6}) is important in organic chemistry, especially in site-selective chlorination reactions, but its product has been a subject of debate for five decades. Previous experimental and theoretical studies provide no concrete conclusion on whether the product is a {pi}- or {sigma}-form of the Cl-C{sub 6}H{sub 6} complex. We took advantage of the diminished cage effect of para-hydrogen (p-H{sub 2}) to produce Cl in situ to react with C{sub 6}H{sub 6} (or C{sub 6}D{sub 6}) upon photolysis of a Cl{sub 2}/C{sub 6}H{sub 6} (or C{sub 6}D{sub 6})/p-H{sub 2} matrix at 3.2more » K. The infrared spectrum, showing intense lines at 1430.5, 833.6, 719.8, 617.0, and 577.4 cm{sup -1}, and several weaker ones for Cl-C{sub 6}H{sub 6}, and the deuterium shifts of observed new lines unambiguously indicate that the product is a 6-chlorocyclohexadienyl radical, i.e., the {sigma}-complex of Cl-C{sub 6}H{sub 6}. Observation of the {sigma}-complex rather than the {pi}-complex indicates that the {sigma}-complex is more stable in solid p-H{sub 2} at 3.2 K. The spectral information is crucial for further investigations of the Cl + C{sub 6}H{sub 6} reaction either in the gaseous or solution phase.« less

Rotational spectrum of the nitrogen trifluoride-chlorine monofluoride complex and the inductive effect of groups R=CH 3, H, F on R 3N/ClF interactions

NASA Astrophysics Data System (ADS)

Waclawik, E. R.; Legon, A. C.; Holloway, J. H.

1998-10-01

Rotational constants B0, centrifugal distortion constants DJ and DJK, and nuclear quadrupole coupling constants χ aa( 14N) and χaa(Cl) were determined by pulsed-nozzle, Fourier transform microwave spectroscopy for the isotopomers F314N⋯ 35ClF and F314N⋯ 37ClF of a complex formed by nitrogen trifluoride and chlorine monofluoride. The distance r(N⋯Cl) and the intermolecular stretching force constant kσ for this symmetric-top species are compared with those of several axially symmetric complexes B⋯ClF in which a nitrogen atom of the base B interacts with ClF. In particular, it is shown that r(N⋯Cl) decreases along the series R 3N⋯ClF, where R=F, H or CH 3, while kσ increases dramatically.

The Effect of Vicinal Versus Geminal Substitution of Hydrogen by Chlorine: Microwave Spectra and Molecular Structures of the Complexes of 1-CHLORO-1-FLUOROETHYLENE and (E)-1-CHLORO-2-FLUOROETHYLENE with Hydrogen Fluoride

NASA Astrophysics Data System (ADS)

Leung, Helen O.; Marshall, Mark D.; Lee, Alex J.; Bozzi, Aaron T.; Cohen, Paul M.; Lam, Mable

2010-06-01

Previous work in our laboratory has demonstrated that increasing the degree of fluorine substitution in complexes of fluoroethylenes with protic acids results in a weaker primary hydrogen-bonding interaction. This has been interpreted as arising from a decrease in the nucleophilicity of the hydrogen bond-accepting fluorine atom as a consequence of the inductive, electron-withdrawing nature of the additional fluorine atoms. We have recently extended these studies to investigate the effects of substitution with the less electronegative, but more polarizable chlorine atom. Through analysis of their 6-21 GHz Fourier transform microwave spectra, molecular structures are obtained for the complexes of 1-chloro-1-fluoroethylene and the (E) isomer of 1-chloro-2-fluoroethylene with hydrogen fluoride. The structures are compared with each other and with their difluoroethylene counterparts.

Pulse radiolysis studies of the reactions of bromine atoms and dimethyl sulfoxide bromine atom complexes with alcohols

NASA Astrophysics Data System (ADS)

Sumiyoshi, Takashi; Fujiyoshi, Ryoko; Katagiri, Miho; Sawamura, Sadashi

2007-05-01

Dimethylsulfoxide (DMSO)-Br complexes were generated by pulse radiolysis of DMSO/bromomethane mixtures and the formation mechanism and spectral characteristics of the formed complexes were investigated in detail. The rate constant for the reaction of bromine atoms with DMSO and the extinction coefficient of the complex were obtained to be 4.6×10 9 M -1 s -1 and 6300 M -1 cm -1 at the absorption maximum of 430 nm. Rate constants for the reaction of bromine atoms with a series of alcohols were determined in CBrCl 3 solutions applying a competitive kinetic method using the DMSO-Br complex as the reference system. The obtained rate constants were ˜10 8 M -1 s -1, one or two orders larger than those reported for highly polar solvents. Rate constants of DMSO-Br complexes with alcohols were determined to be ˜ 10 7 M -1 s -1. A comparison of the reactivities of Br atoms and DMSO-Br complexes with those of chlorine atoms and chlorine atom complexes which are ascribed to hydrogen abstracting reactants strongly indicates that hydrogen abstraction from alcohols is not the rate determining step in the case of Br atoms and DMSO-Br complexes.

Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice

PubMed Central

Sasada, Tatsunari; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Takakura, Yuji; Kawaguchi, Yasuo; Sotomaru, Yusuke; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

2015-01-01

The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma—caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc+/flox, abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apcflox/flox and CDX2P9.5-G22Cre;Apcflox/flox) instability, respectively—were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apcflox/flox and CDX2P9.5-G22Cre;Apcflox/flox mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences in gastrointestinal commensal populations. PMID:26186212

Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice.

PubMed

Sasada, Tatsunari; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Takakura, Yuji; Kawaguchi, Yasuo; Sotomaru, Yusuke; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

2015-01-01

The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox), abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox)) instability, respectively--were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox) mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences in gastrointestinal commensal populations.

Organochlorine Turnover in Forest Ecosystems: The Missing Link in the Terrestrial Chlorine Cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

A Leri; S Myneni

Research in the last 20 years has shown that chlorine undergoes transformations between inorganic and organic forms as part of a complex biogeochemical cycle in terrestrial systems. Natural organochlorine production appears to be associated with the decomposition of plant material on the soil surface, though the chlorine cycle budget implies that a proportion of natural organochlorine enters soil through plant litter and atmospheric deposition as well. Organochlorine compounds may form through biotic and abiotic pathways, but the rates and magnitude of production in the field remain undefined. We have performed a time-dependent trace of chlorine concentration through forest ecosystems, revealingmore » distinct fractions of naturally produced organochlorine in plant biomass. Aliphatic organochlorine constitutes an intrinsic component of healthy leaves that persists through senescence and humification of the plant material, making a substantial contribution to the pool of soil organochlorine. Plant leaves also contain soluble aromatic organochlorine compounds that leach from leaf litter during early decay stages. As decay progresses, high concentrations of insoluble aromatic organochlorine accrue in the humus, through de novo production as well as adsorption. The rates of aromatic organochlorine production and degradation vary seasonally and conversely. This study presents the first unambiguous evidence that there exist multiple pools of chlorinated organic matter in the soil environment and that leaf litter deposition makes a significant and refractory contribution to the soil organochlorine pool, providing key insights into the biogeochemical chlorine cycle.« less

Disinfection Pilot Trial for Little Miami WWTP | Science ...

EPA Pesticide Factsheets

There is a serious interest growing nationally towards the use of PAA at various stages of public waste water treatment facilities; one of such use is secondary waste water treatment. MSDGC is currently interested in improving efficiency and economic aspects of waste water treatment. MSDGC requested for ORD’s support to evaluate alternative cost-effective disinfectants. This report herein is based on the data generated from the field pilot test conducted at the Little Miami Wastewater Treatment Plant. Chlorine assisted disinfection of wastewaters created the concern regarding the formation of high levels of toxic halogenated disinfection byproducts (DBPs) detrimental to aquatic life and public health. Peracetic acid is emerging as a green alternative to chlorine and claimed to have economic and social benefits. In addition, it is a relatively simple retrofit to the existing chlorine treated wastewater treatment facilities. PAA is appealed to possess a much lower aquatic toxicity profile than chlorine and decays rapidly in the environment, even if overdosed. As a result, PAA generally does not need a quenching step, such as dechlorination, reducing process complexity, sodium pollution and cost. PAA treatment does not result in the formation of chlorinated disinfection by-products such as trihalomethanes (THMs), haloacetic acids and other byproducts such as cyanide and n-Nitrosodimethylamine (NDMA).

Monte Carlo analysis of uncertainty propagation in a stratospheric model. 1: Development of a concise stratospheric model

NASA Technical Reports Server (NTRS)

Rundel, R. D.; Butler, D. M.; Stolarski, R. S.

1977-01-01

A concise model has been developed to analyze uncertainties in stratospheric perturbations, yet uses a minimum of computer time and is complete enough to represent the results of more complex models. The steady state model applies iteration to achieve coupling between interacting species. The species are determined from diffusion equations with appropriate sources and sinks. Diurnal effects due to chlorine nitrate formation are accounted for by analytic approximation. The model has been used to evaluate steady state perturbations due to injections of chlorine and NO(X).

Software User’s Manual for the RAILCAR4.1 Toxic Industrial Chemical Source Characterization Program

DTIC Science & Technology

2015-04-01

average cloud area during formation as half of the final cloud area of  Dc2/4.    Since the equations for these parameters can be quite  complex , the...hydrogen chloride  propane (LPG)  chlorine  hydrogen  cyanide  sulfur dioxide  chlorine dioxide  hydrogen fluoride  sulfuric acid  cyanogen chloride

Isolation and identification of Mycobacterium avium complex and other nontuberculosis mycobacteria from drinking-water in Basra governorate, Iraq.

PubMed

Al-Sulami, A A; Al-Taee, A M R; Wida'a, Q H

2012-03-01

This study aimed to determine the occurrence of Mycobacterium avium complex and other nontuberculous mycobacteria in drinking-water in Basra governorate, Iraq and their susceptibility to several antibiotics and the effect of 0.5 mg/L of chlorine on their survival. A total of 404 samples of drinking-water were collected from 33 different districts of the governorate from November 2006 to August 2007. Filtered samples were incubated for 7 days or less in a monophasic-biphasic culture setup of tuberculosis broth and Lowenstein-Jensen agar. The 252 isolates were identified as M. avium complex (21), M. marinum (15), M. kansasii (30), M. simiae (20), M. szulgai (19), M. xenopi (16), M. malmoense (11), M. fortuitum (37), M. chelonae (50) and M. abscessus (33). Isolates were tested for antibiotic susceptibility as well as their ability to tolerate chlorine at a concentration of 0.5 mg/L. The presence of these pathogenic bacteria in drinking-water renders the water unfit for human consumption.

Chelation in root canal therapy reconsidered.

PubMed

Zehnder, Matthias; Schmidlin, Patrick; Sener, Beatrice; Waltimo, Tuomas

2005-11-01

The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.

Alkene epoxidation employing metal nitro complexes

DOEpatents

Andrews, M.A.; Cheng, C.W.; Kelley, K.P.

1982-07-15

Process for converting alkenes to form epoxides utilizes transition metal nitro complexes of the formula: M(RCN)/sub 2/XNO/sub 2/ wherein M is palladium or platinum, R is an alkyl or aryl group containing up to 12 carbon atoms, and X is a monoanionic, monodentate ligand such as chlorine, optionally in the presence of molecular oxygen.

Aniline chlorination by in situ formed Ag-Cl complexes under simulated solar light irradiation.

PubMed

Hu, Xuefeng; Wang, Xiaowen; Dong, Liuliu; Chang, Fei; Luo, Yongming

2015-01-01

Ag speciation in a chloride medium was dependent upon the Cl/Ag ratio after releasing into surface water. In this study, the photoreaction of in situ formed Ag-Cl species and their effects on aniline photochlorination were systematically investigated. Our results suggested that formation of chloroaniline was strongly relevant to the Cl/Ag ratio and could be interpreted using the thermodynamically expected speciation of Ag in the presence of Cl-. AgCl was the main species responsible for the photochlorination of aniline. Both photoinduced hole and •OH drove the oxidation of Cl- to radical •Cl, which promoted the chlorination of aniline. Ag0 formation was observed from the surface plasmon resonance absorption during AgCl photoreaction. This study revealed that Ag+ released into Cl--containing water may result in the formation of chlorinated intermediates of organic compounds under solar light irradiation.

Molecular structure stability of short-chain chlorinated paraffins (SCCPs): Evidence from lattice compatibility and Simha-Somcynsky theories

NASA Astrophysics Data System (ADS)

Yumak, A.; Boubaker, K.; Petkova, P.; Yahsi, U.

2015-10-01

In is known that short-chain chlorinated paraffins (SCCPs) are highly complex technical mixtures of polychlorinated n-alkanes with single chlorine content. Due to their physical properties (viscosity, flame resistance) they are used in many different applications, such as lubricant additives, metal processing, leather fat-liquoring, plastics softening, PVC plasticizing and flame retardants in paints, adhesives and sealants. SCCPs are studied here in terms of processing-linked molecular structure stability, under Simha and Somcynsky-EOS theory calculations and elements from Simha-Somcynsky-related Lattice Compatibility Theory. Analyses were carried out on 1-chloropropane, 2-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chloro 2-methylane, and 2-chloro 2-methylane as (SCCPs) universal representatives. This paper gives evidence to this stability and reviews the current state of knowledge and highlights the need for further research in order to improve future (SCCPs) monitoring efforts.

Performance of an anaerobic, static bed, fixed film bioreactor for chlorinated solvent treatment

USGS Publications Warehouse

Lorah, Michelle M.; Walker, Charles; Graves, Duane

2015-01-01

Anaerobic, fixed film, bioreactors bioaugmented with a dechlorinating microbial consortium were evaluated as a potential technology for cost effective, sustainable, and reliable treatment of mixed chlorinated ethanes and ethenes in groundwater from a large groundwater recovery system. Bench- and pilot-scale testing at about 3 and 13,500 L, respectively, demonstrated that total chlorinated solvent removal to less than the permitted discharge limit of 100 μg/L. Various planned and unexpected upsets, interruptions, and changes demonstrated the robustness and reliability of the bioreactor system, which handled the operational variations with no observable change in performance. Key operating parameters included an adequately long hydraulic retention time for the surface area, a constant supply of electron donor, pH control with a buffer to minimize pH variance, an oxidation reduction potential of approximately −200 millivolts or lower, and a well-adapted biomass capable of degrading the full suite of chlorinated solvents in the groundwater. Results indicated that the current discharge criteria can be met using a bioreactor technology that is less complex and has less downtime than the sorption based technology currently being used to treat the groundwater.

Spatial and vertical distribution of short chain chlorinated paraffins in soils from wastewater irrigated farmlands.

PubMed

Zeng, Lixi; Wang, Thanh; Han, Wenya; Yuan, Bo; Liu, Qian; Wang, Yawei; Jiang, Guibin

2011-03-15

Chlorinated paraffins (CPs) are one of the most complex groups of halogenated contaminants in the environment. However, studies of short chain CPs (SCCPs) in China are very scarce. In this study, the concentrations and distribution of SCCPs in farm soils from a wastewater irrigated area in China were investigated. SCCPs were detected in all topsoil samples, with the sum of the concentrations (ΣSCCPs) in the range of 159.9-1450 ng/g (dry weight, dw). A noticeable spatial trend and specific congener distribution were observed in the wastewater irrigated farmland. Soil vertical profiles showed that ΣSCCP concentrations below the plowed layer decreased exponentially and had a significant positive relationship (R(2) > 0.83) with total organic carbon in soil cores. Furthermore, soil vertical distributions indicated that lower chlorinated (Cl(5-6)) and shorter chain (C(10-12)) congeners are more prone to migrate to deeper soil layers compared to highly chlorinated and longer chain congeners. This work demonstrated that effluents from sewage treatment plants (STPs) could be a significant source of SCCPs to the ambient environment and wastewater irrigation can lead to higher accumulation of SCCPs in farm soils.

Hydrogen/Chlorine exchange reactions of gaseous carbanions.

PubMed

Chen, Hao; Cooks, R Graham; Meurer, Eduardo C; Eberlin, Marcos N

2005-12-01

Gas-phase reactions of three typical carbanions CH(2)NO(2)(-), CH(2)CN(-), and CH(2)S(O)CH(3)(-) with the chloromethanes CH(2)Cl(2), CHCl(3), and CCl(4), examined by tandem mass spectrometry, show a novel hydrogen/chlorine exchange reaction. For example, reaction between the nitromethyl anion CH(2)NO(2)(-) and carbon tetrachloride CCl(4) forms the ion CHClNO(2)(-). The suggested reaction mechanism involves nucleophilic attack by CH(2)NO(2)(-) at the chlorine of CCl(4) followed by proton transfer within the resulting complex [CH(2)ClNO(2) + CCl(3)(-)] to form CHClNO(2)(-) and CHCl(3). Two other carbanions CH(2)CN(-) and CH(2)S(O)CH(3)(-) also undergo the novel hydrogen/chlorine exchange reactions with CCl(4) but to a much smaller extent, their higher nucleophilicities favoring competitive nucleophilic attack reactions. Proton abstraction is the exclusive pathway in the reactions of these carbanions with CHCl(3). While CH(2)CN(-) and CH(2)S(O)CH(3)(-) promote mainly proton abstraction and nucleophilic displacement in reactions with CH(2)Cl(2), CH(2)NO(2)(-) does not react.

The presence of opportunistic pathogens, Legionella spp., L. pneumophila and Mycobacterium avium complex, in South Australian reuse water distribution pipelines.

PubMed

Whiley, H; Keegan, A; Fallowfield, H; Bentham, R

2015-06-01

Water reuse has become increasingly important for sustainable water management. Currently, its application is primarily constrained by the potential health risks. Presently there is limited knowledge regarding the presence and fate of opportunistic pathogens along reuse water distribution pipelines. In this study opportunistic human pathogens Legionella spp., L. pneumophila and Mycobacterium avium complex were detected using real-time polymerase chain reaction along two South Australian reuse water distribution pipelines at maximum concentrations of 10⁵, 10³ and 10⁵ copies/mL, respectively. During the summer period of sampling the concentration of all three organisms significantly increased (P < 0.05) along the pipeline, suggesting multiplication and hence viability. No seasonality in the decrease in chlorine residual along the pipelines was observed. This suggests that the combination of reduced chlorine residual and increased water temperature promoted the presence of these opportunistic pathogens.

Viking Helmet Corroles: Activating Inert Oxidometal Corroles.

PubMed

Schweyen, Peter; Brandhorst, Kai; Hoffmann, Martin; Wolfram, Benedikt; Zaretzke, Marc-Kevin; Bröring, Martin

2017-10-09

Chemically inert oxidometal(V) corrols of molybdenum and rhenium undergo clean ligand-exchange reactions upon the action of SiCl 4 . The resulting dichlorido complexes show trigonal prismatic coordination of the metal ion with the chlorine atoms residing in a cis configuration, and were studied by optical and resonance spectroscopy as well as DFT calculations. In situ reactivity studies with carbon nucleophiles indicate high reactivity for chlorine replacement. Treatment with sodium cyclopentadienide paves the way to robust molybdenum corrolocene half-sandwich complexes. These organometallic compounds are the first corrole species that stabilize an air-stable and diamagnetic low spin d 2 -Mo IV center. Structural, spectroelectrochemical, and chemical investigations prove a reversible Mo IV /Mo V redox couple close to the Fc/Fc + potential for these systems. The high stability of the compounds in both redox states calls for future applications in catalysis and as redox switch. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetics and Near-Infrared Spectroscopy of Organic Peroxy Radicals

NASA Astrophysics Data System (ADS)

Smarte, M. D.; Okumura, M.

2016-12-01

Organic peroxy radicals are important intermediates in atmospheric chemistry with fates that control the rate of radical propagation in an oxidation mechanism. Laboratory methods for detecting peroxy radicals are essential to measuring precise rate constants that constrain these fates. In this work, we discuss the use of near-infrared cavity ringdown spectroscopy to detect organic peroxy radicals for the purpose of laboratory kinetics measurements. We focus on chlorine-substituted peroxy radicals generated in the oxidation of alkenes by chlorine, a minor tropospheric oxidant found in marine and coastal regions. Previous kinetics experiments on peroxy radicals have largely used UV absorption spectroscopy via the dissociative B-X transition. However, the spectra produced are featureless and exhibit substantial overlap; determining the concentration profile of an individual peroxy radical can be an arduous task. In our work, we probe the forbidden peroxy radical A-X transition in the near-infrared. While this approach requires overcoming small cross sections ( 10-21 cm2), the A state is bound and leads to structured absorption spectra that may be useful in constraining the kinetics of mixtures of organic peroxy radicals formed in the oxidation of complex hydrocarbons. Only a few kinetics studies utilizing the A-X transition exist in the literature and they are focused on small, unsubstituted species. This presentation explores the ability of the A-X transition to unravel the kinetics of more complex peroxy radicals in laboratory experiments using several example systems: (1) Determining rate constants for the self and cross reactions of β-chloroethylperoxy and HO2. (2) Detecting the second generation of peroxy radicals formed from alkoxy radical decomposition in the chlorine-initiated oxidation of 2-butene. (3) Observing different rates of reactivity with NO across the pool of peroxy radical isomers formed in the chlorine-initiated oxidation of isoprene.

Biological reduction of chlorinated solvents: Batch-scale geochemical modeling

NASA Astrophysics Data System (ADS)

Kouznetsova, Irina; Mao, Xiaomin; Robinson, Clare; Barry, D. A.; Gerhard, Jason I.; McCarty, Perry L.

2010-09-01

Simulation of biodegradation of chlorinated solvents in dense non-aqueous phase liquid (DNAPL) source zones requires a model that accounts for the complexity of processes involved and that is consistent with available laboratory studies. This paper describes such a comprehensive modeling framework that includes microbially mediated degradation processes, microbial population growth and decay, geochemical reactions, as well as interphase mass transfer processes such as DNAPL dissolution, gas formation and mineral precipitation/dissolution. All these processes can be in equilibrium or kinetically controlled. A batch modeling example was presented where the degradation of trichloroethene (TCE) and its byproducts and concomitant reactions (e.g., electron donor fermentation, sulfate reduction, pH buffering by calcite dissolution) were simulated. Local and global sensitivity analysis techniques were applied to delineate the dominant model parameters and processes. Sensitivity analysis indicated that accurate values for parameters related to dichloroethene (DCE) and vinyl chloride (VC) degradation (i.e., DCE and VC maximum utilization rates, yield due to DCE utilization, decay rate for DCE/VC dechlorinators) are important for prediction of the overall dechlorination time. These parameters influence the maximum growth rate of the DCE and VC dechlorinating microorganisms and, thus, the time required for a small initial population to reach a sufficient concentration to significantly affect the overall rate of dechlorination. Self-inhibition of chlorinated ethenes at high concentrations and natural buffering provided by the sediment were also shown to significantly influence the dechlorination time. Furthermore, the analysis indicated that the rates of the competing, nonchlorinated electron-accepting processes relative to the dechlorination kinetics also affect the overall dechlorination time. Results demonstrated that the model developed is a flexible research tool that is able to provide valuable insight into the fundamental processes and their complex interactions during bioremediation of chlorinated ethenes in DNAPL source zones.

Kinetics and mechanism of styrene epoxidation by chlorite: role of chlorine dioxide.

PubMed

Leigh, Jessica K; Rajput, Jonathan; Richardson, David E

2014-07-07

An investigation of the kinetics and mechanism for epoxidation of styrene and para-substituted styrenes by chlorite at 25 °C in the pH range of 5-6 is described. The proposed mechanism in water and water/acetonitrile includes seven oxidation states of chlorine (-I, 0, I, II, III, IV, and V) to account for the observed kinetics and product distributions. The model provides an unusually detailed quantitative mechanism for the complex reactions that occur in mixtures of chlorine species and organic substrates, particularly when the strong oxidant chlorite is employed. Kinetic control of the reaction is achieved by the addition of chlorine dioxide to the reaction mixture, thereby eliminating a substantial induction period observed when chlorite is used alone. The epoxidation agent is identified as chlorine dioxide, which is continually formed by the reaction of chlorite with hypochlorous acid that results from ClO produced by the epoxidation reaction. The overall stoichiometry is the result of two competing chain reactions in which the reactive intermediate ClO reacts with either chlorine dioxide or chlorite ion to produce hypochlorous acid and chlorate or chloride, respectively. At high chlorite ion concentrations, HOCl is rapidly eliminated by reaction with chlorite, minimizing side reactions between HOCl and Cl2 with the starting material. Epoxide selectivity (>90% under optimal conditions) is accurately predicted by the kinetic model. The model rate constant for direct reaction of styrene with ClO2(aq) to produce epoxide is (1.16 ± 0.07) × 10(-2) M(-1) s(-1) for 60:40 water/acetonitrile with 0.20 M acetate buffer. Rate constants for para substituted styrenes (R = -SO3(-), -OMe, -Me, -Cl, -H, and -NO2) with ClO2 were determined. The results support the radical addition/elimination mechanism originally proposed by Kolar and Lindgren to account for the formation of styrene oxide in the reaction of styrene with chlorine dioxide.

Chlorination by-product concentration levels in seawater and fish of an industrialised bay (Gulf of Fos, France) exposed to multiple chlorinated effluents.

PubMed

Boudjellaba, D; Dron, J; Revenko, G; Démelas, C; Boudenne, J-L

2016-01-15

Chlorination is one of the most widely used techniques for biofouling control in large industrial units, leading to the formation of halogenated chlorination by-products (CBPs). This study was carried out to evaluate the distribution and the dispersion of these compounds within an industrialised bay hosting multiple chlorination discharges issued from various industrial processes. The water column was sampled at the surface and at 7 m depth (or bottom) in 24 stations for the analysis of CBPs, and muscle samples from 15 conger eel (Conger conger) were also investigated. Temperature and salinity profiles supported the identification of the chlorination releases, with potentially complex patterns. Chemical analyses showed that bromoform was the most abundant CBP, ranging from 0.5 to 2.2 μg L(-1) away from outlets (up to 10 km distance), and up to 18.6 μg L(-1) in a liquefied natural gas (LNG) regasification plume. However, CBP distributions were not homogeneous, halophenols being prominent in a power station outlet and dibromoacetonitrile in more remote stations. A seasonal effect was identified as fewer stations revealed CBPs in summer, probably due to the air and water temperatures increases favouring volatilisation and reactivity. A simple risk assessment of the 11 identified CBPs showed that 7 compounds concentrations were above the potential risk levels to the local marine environment. Finally, conger eel muscles presented relatively high levels of 2,4,6-tribromophenol, traducing a generalised impregnation of the Gulf of Fos to CBPs and a global bioconcentration factor of 25 was determined for this compound. Copyright © 2015 Elsevier B.V. All rights reserved.

A novel two-dimensional liquid-chromatography method for online prediction of the toxicity of transformation products of benzophenones after water chlorination.

PubMed

Li, Jian; Ma, Li-Yun; Xu, Li; Shi, Zhi-Guo

2015-08-01

Benzophenone-type UV filters (BPs) are ubiquitous in the environment. Transformation products (TPs) of BPs with suspected toxicity are likely to be produced during disinfection of water by chlorination. To quickly predict the toxicity of TPs, in this study, a novel two-dimensional liquid-chromatography (2D-LC) method was established in which the objective of the first dimension was to separate the multiple components of the BPs sample after chlorination, using a reversed-phase liquid-chromatography mode. A biochromatographic system, i.e. bio-partitioning micellar chromatography with the polyoxyethylene (23) lauryl ether aqueous solution as the mobile phase, served as the second dimension to predict the toxicity of the fraction from the first dimension on the basis of the quantitative retention-activity relationships (QRARs) model. Six BPs, namely 2,4-dihydroxybenzophenone, oxybenzone, 4-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone, were the target analytes subjected to chlorination. The products of these BPs after chlorination were directly injected to the 2D-LC system for analysis. The results indicated that most TPs may be less toxic than their parent chemicals, but some may be more toxic, and that intestinal toxicity of TPs may be more obvious than blood toxicity. The proposed method is time-saving, high-throughput, and reliable, and has great potential for predicting toxicity or bioactivity of unknown and/or known components in a complex sample. Graphical Abstract The scheme for the 2D-LC online prediction of toxicity of the transformation products of benzophenone-type UV filters after chlorination.

Molecular characterization of low molecular weight dissolved organic matter in water reclamation processes using Orbitrap mass spectrometry.

PubMed

Phungsai, Phanwatt; Kurisu, Futoshi; Kasuga, Ikuro; Furumai, Hiroaki

2016-09-01

Reclaimed water has recently become an important water source for urban use, but the composition of dissolved organic matter (DOM) in reclaimed water has rarely been characterized at the compound level because of its complexity. In this study, the transformation and changes in composition of low molecular weight DOM in water reclamation processes, where secondary effluent of the municipal wastewater treatment plant was further treated by biofiltration, ozonation and chlorination, were investigated by "unknown" screening analysis using Orbitrap mass spectrometry (Orbitrap MS). The intense ions were detected over an m/z range from 100 to 450. In total, 2412 formulae with various heteroatoms were assigned, and formulae with carbon (C), hydrogen (H) and oxygen (O) only and C, H, O and sulfur (S) were the most abundant species. During biofiltration, CHO-only compounds with relatively high hydrogen to carbon (H/C) ratio or with saturated structure were preferentially removed, while CHOS compounds were mostly removed. Ozonation induced the greatest changes in DOM composition. CHOS compounds were mostly decreased after ozonation while ozone selectively removed CHO compounds with relatively unsaturated structure and produced compounds that were more saturated and with a higher degree of oxidation. After chlorination, 168 chlorine-containing formulae, chlorinated disinfection by-products (DBPs), were additionally detected. Candidate DBP precursors were determined by tracking chlorinated DBPs formed via electrophilic substitution, half of which were generated during the ozonation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Considerations about projectile and target X-rays induced during heavy ion bombardment

NASA Astrophysics Data System (ADS)

Fernandes, F.; Bauer, D. V.; Duarte, A.; Ferrari, T. M.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

2018-02-01

In this work we present some results concerning the X-rays emitted by heavy ions during target bombardment. In this case, Cl4+ and Cl5+ ions with energies from 4 MeV to 10 MeV were employed to irradiate vitreous carbon planchets. Moreover, total X-ray production cross sections of titanium X-rays induced by chlorine ions were obtained as well for the same energy range. Only inner shell transitions were considered in the present work. The titanium target consisted of a thin film deposited over vitreous carbon planchets. The results indicate that the projectile X-ray yields increase as a function of the bombarding energy for the present energy range. Effects due to projectile charge state appears to be of minor importance at these low ion velocities. It is shown that a simple exponential function can represent the continuum background of such complex spectra. The chlorine transition rates Kβ/Kα obtained from chlorine acting as a projectile interacting with a carbon target are about half the value when compared to the chlorine Kβ/Kα ratios obtained when a LiCl target is bombarded with C+ and C3+ ions with energies from 2 MeV to 6 MeV. As far as the total X-ray production cross sections of Ti induced by chlorine ions are concerned, the ECPSSR theory underestimates the Ti total X-rays production cross sections by several orders of magnitude. The role of electron capture and possible mechanisms responsible for these effects are discussed.

The quantification of short-chain chlorinated paraffins in sediment samples using comprehensive two-dimensional gas chromatography with μECD detection.

PubMed

Muscalu, Alina M; Morse, Dave; Reiner, Eric J; Górecki, Tadeusz

2017-03-01

The analysis of persistent organic pollutants in environmental samples is a challenge due to the very large number of compounds with varying chemical and physical properties. Chlorinated paraffins (CPs) are complex mixtures of chlorinated n-alkanes with varying chain lengths (C 10 to C 30 ) and degree of chlorination (30 to 70% by weight). Their physical-chemical properties make these compounds persistent in the environment and able to bioaccumulate in living organisms. Comprehensive two-dimensional gas chromatography (GC × GC) coupled with micro-electron capture detection (μECD) was used to separate and quantify short-chain chlorinated paraffins (SCCP) in sediment samples. Distinct ordered bands were observed in the GC × GC chromatograms pointing to group separation. Using the Classification function of the ChromaTOF software, summary tables were generated to determine total area counts to set up multilevel-calibration curves for different technical mixes. Fortified sediment samples were analyzed by GC × GC-μECD with minimal extraction and cleanup. Recoveries ranged from 120 to 130%. To further validate the proposed method for the analysis of SCCPs, the laboratory participated in interlaboratory studies for the analysis of standards and sediment samples. The results showed recoveries between 75 and 95% and z-score values <2, demonstrating that the method is suitable for the analysis of SCCPs in soil/sediment samples. Graphical abstract Quantification of SCCPs by 2D-GC-μECD.

Discovery and characterization of a marine bacterial SAM-dependent chlorinase

PubMed Central

Eustáquio, Alessandra S; Pojer, Florence; Noel, Joseph P; Moore, Bradley S

2009-01-01

Halogen atom incorporation into a scaffold of bioactive compounds often amplifies biological activity, as is the case for the anticancer agent salinosporamide A (1), a chlorinated natural product from the marine bacterium Salinispora tropica. Significant effort in understanding enzymatic chlorination shows that oxidative routes predominate to form reactive electrophilic or radical chlorine species. Here we report the genetic, biochemical and structural characterization of the chlorinase SalL, which halogenates S-adenosyl-l-methionine (2) with chloride to generate 5′-chloro-5′-deoxyadenosine (3) and l-methionine (4) in a rarely observed nucleophilic substitution strategy analogous to that of Streptomyces cattleya fluorinase. Further metabolic tailoring produces a halogenated polyketide synthase substrate specific for salinosporamide A biosynthesis. SalL also accepts bromide and iodide as substrates, but not fluoride. High-resolution crystal structures of SalL and active site mutants complexed with substrates and products support the SN2 nucleophilic substitution mechanism and further illuminate halide specificity in this newly discovered halogenase family. PMID:18059261

Short chain chlorinated paraffins in mollusks from coastal waters in the Chinese Bohai Sea.

PubMed

Yuan, Bo; Wang, Thanh; Zhu, Nali; Zhang, Kegang; Zeng, Lixi; Fu, Jianjie; Wang, Yawei; Jiang, Guibin

2012-06-19

As an extremely complex group of persistent organic pollutants (POPs) candidates in the Stockholm Convention, short chain chlorinated paraffins (SCCPs) have been of extensive concern in recent years. In this study, nine bivalve and two gastropod species were collected in 2009 to evaluate the spatial distributions and potential factors influencing the bioaccumulation of SCCPs in mollusks in the Chinese Bohai Sea. The concentrations of ∑ SCCPs in the mollusks were in the range 64.9-5510 ng/g (dry weight) with an average chlorine content of 61.1%. C(10) and C(11) were the predominant homologue groups of SCCPs, which accounted for about 29.7% and 34.9% of ∑ SCCPs, respectively. Six and seven chlorinated substituents were the main congener groups. Mya arenaria (Mya), Mactra veneriformis (Mac), and Crassostrea talienwhanensis (Oyster, Ost) had higher average concentrations of SCCPs than other species, implying that these bivalves could be used as sentinels to indicate SCCPs contamination in this coastal region. A significant positive linear relationship was found between SCCP concentrations and lipid content of the mollusks, whereas the lipid-normalized SCCP concentrations were negatively linear-related to the trophic levels (TL), which implied that SCCPs did not show biomagnification in mollusks in this region.

Quantification of Short-Chain Chlorinated Paraffins by Deuterodechlorination Combined with Gas Chromatography-Mass Spectrometry.

PubMed

Gao, Yuan; Zhang, Haijun; Zou, Lili; Wu, Ping; Yu, Zhengkun; Lu, Xianbo; Chen, Jiping

2016-04-05

Analysis of short-chain chlorinated paraffins (SCCPs) is extremely difficult because of their complex compositions with thousands of isomers and homologues. A novel analytical method, deuterodechlorination combined with high resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS), was developed. A protocol is applied in the deuterodechlorination of SCCPs with LiAlD4, and the formed deuterated n-alkanes of different alkane chains can be distinguished readily from each other on the basis of their retention time and fragment mass ([M](+)) by HRGC-HRMS. An internal standard quantification of individual SCCP congeners was achieved, in which branched C10-CPs and branched C12-CPs were used as the extraction and reaction internal standards, respectively. A maximum factor of 1.26 of the target SCCP concentrations were determined by this method, and the relative standard deviations for quantification of total SCCPs were within 10%. This method was applied to determine the congener compositions of SCCPs in commercial chlorinated paraffins and environmental and biota samples after method validation. Low-chlorinated SCCP congeners (Cl1-4) were found to account for 32.4%-62.4% of the total SCCPs. The present method provides an attractive perspective for further studies on the toxicological and environmental characteristics of SCCPs.

Disinfection of Ebola Virus in Sterilized Municipal Wastewater

PubMed Central

Fischer, Robert J.; Casson, Leonard W.; de Carvalho, Nathalia Aquino; Haas, Charles N.; Munster, Vincent J.

2017-01-01

Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification. PMID:28146555

Disinfection of Ebola Virus in Sterilized Municipal Wastewater.

PubMed

Bibby, Kyle; Fischer, Robert J; Casson, Leonard W; de Carvalho, Nathalia Aquino; Haas, Charles N; Munster, Vincent J

2017-02-01

Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification.

TECHNIQUES FOR ANALYZING COMPLEX MIXTURES OF DRINKING WATER DBPS

EPA Science Inventory

Although chlorine has been used to disinfect drinking water for approximately 100 years, there have been concerns raised over its use, due to the formation of potentially hazardous by-products. Trihalomethanes (THMs) were the first disinfection by-products (DBPs) identified and ...

Biological instability in a chlorinated drinking water distribution network.

PubMed

Nescerecka, Alina; Rubulis, Janis; Vital, Marius; Juhna, Talis; Hammes, Frederik

2014-01-01

The purpose of a drinking water distribution system is to deliver drinking water to the consumer, preferably with the same quality as when it left the treatment plant. In this context, the maintenance of good microbiological quality is often referred to as biological stability, and the addition of sufficient chlorine residuals is regarded as one way to achieve this. The full-scale drinking water distribution system of Riga (Latvia) was investigated with respect to biological stability in chlorinated drinking water. Flow cytometric (FCM) intact cell concentrations, intracellular adenosine tri-phosphate (ATP), heterotrophic plate counts and residual chlorine measurements were performed to evaluate the drinking water quality and stability at 49 sampling points throughout the distribution network. Cell viability methods were compared and the importance of extracellular ATP measurements was examined as well. FCM intact cell concentrations varied from 5×10(3) cells mL(-1) to 4.66×10(5) cells mL(-1) in the network. While this parameter did not exceed 2.1×10(4) cells mL(-1) in the effluent from any water treatment plant, 50% of all the network samples contained more than 1.06×10(5) cells mL(-1). This indisputably demonstrates biological instability in this particular drinking water distribution system, which was ascribed to a loss of disinfectant residuals and concomitant bacterial growth. The study highlights the potential of using cultivation-independent methods for the assessment of chlorinated water samples. In addition, it underlines the complexity of full-scale drinking water distribution systems, and the resulting challenges to establish the causes of biological instability.

Biological Instability in a Chlorinated Drinking Water Distribution Network

PubMed Central

Nescerecka, Alina; Rubulis, Janis; Vital, Marius; Juhna, Talis; Hammes, Frederik

2014-01-01

The purpose of a drinking water distribution system is to deliver drinking water to the consumer, preferably with the same quality as when it left the treatment plant. In this context, the maintenance of good microbiological quality is often referred to as biological stability, and the addition of sufficient chlorine residuals is regarded as one way to achieve this. The full-scale drinking water distribution system of Riga (Latvia) was investigated with respect to biological stability in chlorinated drinking water. Flow cytometric (FCM) intact cell concentrations, intracellular adenosine tri-phosphate (ATP), heterotrophic plate counts and residual chlorine measurements were performed to evaluate the drinking water quality and stability at 49 sampling points throughout the distribution network. Cell viability methods were compared and the importance of extracellular ATP measurements was examined as well. FCM intact cell concentrations varied from 5×103 cells mL−1 to 4.66×105 cells mL−1 in the network. While this parameter did not exceed 2.1×104 cells mL−1 in the effluent from any water treatment plant, 50% of all the network samples contained more than 1.06×105 cells mL−1. This indisputably demonstrates biological instability in this particular drinking water distribution system, which was ascribed to a loss of disinfectant residuals and concomitant bacterial growth. The study highlights the potential of using cultivation-independent methods for the assessment of chlorinated water samples. In addition, it underlines the complexity of full-scale drinking water distribution systems, and the resulting challenges to establish the causes of biological instability. PMID:24796923

Mechanistic insights into the one-pot synthesis of propargylamines from terminal alkynes and amines in chlorinated solvents catalyzed by gold compounds and nanoparticles.

PubMed

Aguilar, David; Contel, Maria; Urriolabeitia, Esteban P

2010-08-09

Propargylamines can be obtained from secondary amines and terminal alkynes in chlorinated solvents by a three- and two-component synthesis catalyzed by gold compounds and nanoparticles (Au-NP) under mild conditions. The use of dichloromethane allows for the activation of two C-Cl bonds and a clean transfer of the methylene fragment to the final product. The scope of the reaction as well as the influence of different gold(III) cycloaurated complexes and salts has been investigated. The involvement of gold nanoparticles generated in situ in the process is discussed and a plausible reaction mechanism is proposed on the basis of the data obtained.

Iron(II,III)-polyphenol complex nanoparticles derived from green tea with remarkable ecotoxicological impact

EPA Science Inventory

There are several greener methods exist to synthesize zero–valent iron nanoparticles (nZVI) using different bio-based reducing agents. Although their useful properties in degradation of organic dyes, chlorinated organics, or arsenic have been described earlier, their characteriza...

Drinking water chlorination and cancer-a historical cohort study in Finland.

PubMed

Koivusalo, M; Pukkala, E; Vartiainen, T; Jaakkola, J J; Hakulinen, T

1997-03-01

Chlorination of water rich in organic material is known to produce a complex mixture of organochlorine compounds, including mutagenic and carcinogenic substances. A historical cohort study of 621,431 persons living in 56 towns in Finland was conducted in order to assess the relation between historical exposure to drinking water mutagenicity and cancer. Exposure to quantity of mutagenicity was calculated on the basis of historical information of raw water quality and water treatment practices using an empirical equation relating mutagenicity and raw water pH, KMnO4 value and chlorine dose. Cancer cases were derived from the population-based Finnish Cancer Registry and follow-up time in the study started in 1970. Age, gender, time period, social class, and urban residence were taken into account in Poisson regression analysis of the observed numbers of cases using expected numbers of cases standardized for age and gender as a basis. Excess risks were calculated using a continuous variable for mutagenicity for 3,000 net rev/l exposure representing an average exposure in a town using chlorinated surface water. After adjustment for confounding, a statistically significant excess risk was observed for women in cancers of the bladder (relative risk [RR] = 1.48, 95 percent confidence interval [CI] = 1.01-2.18), rectum (RR = 1.38, CI = 1.03-1.85), esophagus (RR = 1.90, CI = 1.02-3.52), and breast (RR = 1.11, CI = 1.01-1.22). These results support the magnitude of excess risks for rectal and bladder cancers found in earlier epidemiologic studies on chlorination by-products and give additional information on exposure-response concerning the mutagenic compounds. Nevertheless, due to the public health importance of water chlorination, uncertainty related to the magnitude of observed risks, and the fact that excess risks were observed only for women, the results of the study should be interpreted with caution.

Oxidation of Cr(III)-Fe(III) Mixed-phase Hydroxides by Chlorine: Implications on the Control of Hexavalent Chromium in Drinking Water.

PubMed

Chebeir, Michelle; Liu, Haizhou

2018-05-17

The occurrence of chromium (Cr) as an inorganic contaminant in drinking water is widely reported. One source of Cr is its accumulation in iron-containing corrosion scales of drinking water distribution systems as Cr(III)-Fe(III) hydroxide, i.e., FexCr(1-x)(OH)3(s), where x represents the Fe(III) molar content and typically varies between 0.25 and 0.75. This study investigated the kinetics of inadvertent hexavalent chromium Cr(VI) formation via the oxidation of FexCr(1-x)(OH)3(s) by chlorine as a residual disinfectant in drinking water, and examined the impacts of Fe(III) content and drinking water chemical parameters including pH, bromide and bicarbonate on the rate of Cr(VI) formation. Data showed that an increase in Fe(III) molar content resulted in a significant decrease in the stoichiometric Cr(VI) yield and the rate of Cr(VI) formation, mainly due to chlorine decay induced by Fe(III) surface sites. An increase in bicarbonate enhanced the rate of Cr(VI) formation, likely due to the formation of Fe(III)-carbonato surface complexes that slowed down the scavenging reaction with chlorine. The presence of bromide significantly accelerated the oxidation of FexCr(1-x)(OH)3(s) by chlorine, resulting from the catalytic effect of bromide acting as an electron shuttle. A higher solution pH between 6 and 8.5 slowed down the oxidation of Cr(III) by chlorine. These findings suggested that the oxidative conversion of chromium-containing iron corrosion products in drinking water distribution systems can lead to the occurrence of Cr(VI) at the tap, and the abundance of iron, and a careful control of pH, bicarbonate and bromide levels can assist the control of Cr(VI) formation.

Factorial analysis of the trihalomethane formation in the reaction of colloidal, hydrophobic, and transphilic fractions of DOM with free chlorine.

PubMed

Platikanov, Stefan; Tauler, Roma; Rodrigues, Pedro M S M; Antunes, Maria Cristina G; Pereira, Dilson; Esteves da Silva, Joaquim C G

2010-09-01

This study focuses on the factors that affect trihalomethane (THMs) formation when dissolved organic matter (DOM) fractions (colloidal, hydrophobic, and transphilic fractions) in aqueous solutions were disinfected with chlorine. DOM fractions were isolated and fractionated from filtered lake water and were characterized by elemental analysis. The investigation involved a screening Placket-Burman factorial analysis design of five factors (DOM concentration, chlorine dose, temperature, pH, and bromide concentration) and a Box-Behnken design for a detailed assessment of the three most important factor effects (DOM concentration, chlorine dose, and temperature). The results showed that colloidal fraction has a relatively low contribution to THM formation; transphilic fraction was responsible for about 50% of the chloroform generation, and the hydrophobic fraction was the most important to the brominated THM formation. When colloidal and hydrophobic fraction solutions were disinfected, the most significant factors were the following: higher DOM fraction concentration led to higher THM concentration, an increase of pH corresponded to higher concentration levels of chloroform and reduced bromoform, higher levels of chlorine dose and temperature produced a rise in the total THM formation, especially of the chlorinated THMs; higher bromide concentration generates higher concentrations of brominated THMs. Moreover, linear models were implemented and response surface plots were obtained for the four THM concentrations and their total sum in the disinfection solution as a function of the DOM concentration, chlorine dose, and temperature. Overall, results indicated that THM formation models were very complex due to individual factor effects and significant interactions among the factors. In order to reduce the concentration of THMs in drinking water, DOM concentrations must be reduced in the water prior to the disinfection. Fractionation of DOM, together with an elemental analysis of the fractions, is important issue in the revealing of the quality and quantity characteristics of DOM. Systematic study composed from DOM fraction investigation and factorial analysis of the responsible parameters in the THM formation reaction can, after an evaluation of the adjustment of the models with the reality, serves well for the evaluation of the spatial and temporal variability in the THM formation in dependence of DOM. However, taking into consideration the natural complexity of DOM, different operations and a strict control of them (like coagulation/flocculation and filtration) has to be used to quantitatively remove DOM from the raw water. Assuming that this study represents a local case study, similar experiments can be easily applied and will supply with relevant information every local water treatment plant meeting problems with THM formation. The coagulation/flocculation and the filtration stages are the main mechanisms to remove DOM, particularly the colloidal DOM fraction. With the objective to minimize THMs generation, different unit operation designed to quantitatively remove DOM from water must be optimized.

Atomic Force Microscopy (AFM) for In-Situ Biofilm Surface Characterization during Free Chlorine and Monochloramine Exposure

EPA Science Inventory

Drinking water distribution system biofilm are attached to pipe walls and found in sediments. These biofilms are complex and contain a variety of microorganisms embedded in a matrix with extracellular polymeric substances (EPS), providing protection from disinfection. Without pro...

INTEGRATED DISINFECTION BYPRODUCTS MIXTURES RESEARCH: COMPREHENSIVE CHARACTERIZATION OF WATER CONCENTRATES PREPARED FROM CHLORINATED AND OZONATED/POSTCHLORINATED DRINKING WATER

EPA Science Inventory

This article describes the disinfection byproduct (DBP) characterization portion of a series of experiments designed for comprehensive chemical and toxicological evaluation of two drinking water concentrates containing highly complex mixtures of DBP. This project, called the Four...

Adsorption of Pd(II) complexes from chloride solutions obtained by leaching chlorinated spent automotive catalysts on ion exchange resin Diaion WA21J.

PubMed

Shen, Shaobo; Pan, Tonglin; Liu, Xinqiang; Yuan, Lei; Zhang, Yongjian; Wang, Jinchao; Guo, Zhanchen

2010-05-01

It was found that Rh, Pd and Pt contained in the spent ceramic automotive catalysts could be effectively extracted by dry chlorination with chlorine. In order to concentrate Pd(II) contained in the chloride solution obtained from the dry chlorination process, thermodynamic and kinetics studies for adsorption of Pd(II) complexes from the chloride solutions on anionic exchange resin Diaion WA21J were carried out. It was found that Pd, Pt, Rh, Al, Fe, Si, Zn and Pb from the chloride solution could be adsorbed on the resin. The isothermal adsorption of Pd(II) was found to fit Freundlich, Langmuir and Dubinin-Kaganer-Radushkevich models under the adsorption conditions. The adsorption of Pd(II) on the resin was favorable according to the values of 1/n and R(L) from Freundlich and Langmuir adsorption isotherms, respectively. The maximum monolayer adsorption capacities Q(max) based on Langmuir adsorption isotherms were 5.70, 4.84 and 4.05 mg/g and the corresponding value X(m) based on Dubinin-Kaganer-Radushkevich were 5.55, 4.69 and 4.01 mg/g at temperatures 18 degrees C, 28 degrees C and 40 degrees C, respectively. The apparent adsorption energies (E(ad)) based on Dubinin-Kaganer-Radushkevich isotherm were -15.43, -16.22 and -23.57 kJ/mol for the temperatures 18 degrees C, 28 degrees C and 40 degrees C, respectively. Chemical adsorption was a main mechanism involved in the adsorption process. Pd(II) adsorption on the resin could be accelerated by increasing the adsorption temperature. The adsorption of Pd(II) from the chloride solution on the resin underwent pseudo-first order kinetic process and the apparent adsorption activation energy E(a) was 15.0 kJ/mol. The intra-particle diffusion was a main rate controlling step in the Pd(II) adsorption process under the adsorption conditions. Copyright 2010 Elsevier Inc. All rights reserved.

Contamination of environment in the road surroudings - impact of road salting on Norway spruce (Picea abies) and Scots pine (Pinus sylvestris)

NASA Astrophysics Data System (ADS)

Hegrová, Jitka; Steiner, Oliver; Goessler, Walter; Tanda, Stefan; Anděl, Petr

2017-09-01

A comprehensive overview of the influence of transport on the environment is presented in this study. The complex analysis of soil and needle samples provides an extensive set of data, which presents elemental contamination of the environment near roads. Traffic pollution (including winter road treatment) has a significant negative influence on our environment. Besides sodium and chlorine from winter maintenance many other elements are emitted into the environment. Three possible sources of contamination are assumed for environmental contamination evaluation: car emission, winter maintenance and abrasion from breaks and clutches. The chemical analysis focused on the description of samples from inorganic point of view. The influence of the contamination potential on the sodium and chlorine content in the samples of 1st year-old and 2nd year-old needles of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) is discussed. Additional soil samples were taken from each sampling site and analyzed to get insight in the sodium and chlorine distribution. Statistical evaluation was used for interpretation of complex interaction patterns between element concentrations in different aged needles based on localities character including distance from the road and element concentration in soils. This species of needles were chosen because of its heightened sensitivity towards salinization. The study was conducted in different parts of the Czech Republic. The resulting database is a source of valuable information about the influence of transport on the environment.

Adsorption of Rh(III) complexes from chloride solutions obtained by leaching chlorinated spent automotive catalysts on ion-exchange resin Diaion WA21J.

PubMed

Shen, Shaobo; Pan, Tonglin; Liu, Xinqiang; Yuan, Lei; Wang, Jinchao; Zhang, Yongjian; Guo, Zhanchen

2010-07-15

It was found that Rh, Pd and Pt contained in the spent ceramic automotive catalysts could be effectively extracted by dry chlorination with chlorine. In order to concentrate Rh(III) ions contained in the chloride solutions obtained, thermodynamic and kinetics studies for adsorption of Rh(III) complexes from the chloride solutions on an anionic exchange resin Diaion WA21J were carried out. Rh, Pd, Pt, Al, Fe, Si, Zn and Pb from the chloride solution could be adsorbed on the resin. The distribution coefficients (K(d)) of Rh(III) decreased with the increase in initial Rh(III) concentration or in adsorption temperature. The isothermal adsorption of Rh(III) was found to fit Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich models under the adsorption conditions. The maximum monolayer adsorption capacities Q(max) based on Langmuir adsorption isotherms were 6.39, 6.61 and 5.81 mg/g for temperatures 18, 28 and 40 degrees C, respectively. The apparent adsorption energy of Rh was about -7.6 kJ/mol and thus Rh(III) adsorption was a physical type. The experimental data obtained could be better simulated by pseudo-first-order kinetic model and the activation energy obtained was 6.54 J/mol. The adsorption rate of Rh(III) was controlled by intraparticle diffusion in most of time of adsorption process. 2010 Elsevier B.V. All rights reserved.

Characterization of unknown brominated disinfection byproducts during chlorination using ultrahigh resolution mass spectrometry.

PubMed

Zhang, Haifeng; Zhang, Yahe; Shi, Quan; Zheng, Hongdie; Yang, Min

2014-03-18

Brominated disinfection byproducts (Br-DBPs), formed from the reaction of disinfectant(s) with natural organic matter in the presence of bromide in raw water, are generally more cytotoxic and genotoxic than their chlorinated analogues. To date, only a few Br-DBPs in drinking water have been identified, while a significant portion of Br-DBPs in drinking water is still unknown. In this study, negative ion electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown Br-DBPs in artificial drinking water. In total, 441 formulas for one-bromine-containing products and 37 formulas for two-bromine-containing products, most of which had not been previously reported, were detected in the chlorinated sample. Most Br-DBPs have corresponding chlorine-containing analogues with identical CHO composition. In addition, on-resonance collision-induced dissociation (CID) of single ultrahigh resolved bromine containing mass peaks was performed in the ICR cell to isolate single bromine-containing components in a very complex natural organic matter spectrum and provide structure information. Relatively abundant neutral loss of CO2 was observed in MS-MS spectra, indicating that the unknown Br-DBPs are rich in carboxyl groups. The results demonstrate that the ESI FT-ICR MS method could provide valuable molecular composition and structure information on unknown Br-DBPs.

Short-chain chlorinated paraffins (SCCPs) in surface soil from a background area in China: occurrence, distribution, and congener profiles.

PubMed

Wang, Xue-Tong; Zhang, Yuan; Miao, Yi; Ma, Ling-Ling; Li, Yuan-Cheng; Chang, Yue-Ya; Wu, Ming-Hong

2013-07-01

Short-chain chlorinated paraffins (SCCPs) are extremely complex technical mixtures of polychlorinated n-alkanes with carbon chain lengths from C10 to C13 and chlorine content between 49 and 70%. SCCPs are under consideration for inclusion in the Stockholm Convention on persistent organic pollutants. SCCPs have been used extensively in industrial production, but little is known about the pollution level in soil environment in China. In this study, levels and distribution of SCCPs in soil samples from Chongming Island were analyzed. Concentrations of total SCCPs in soil samples ranged from 0.42 to 420 ng g(-1), with a median of 9.6 ng g(-1). The ubiquitous occurrence of SCCPs in Chongming Island implied that long-range atmospheric transport and soil-air exchange may be the most important pathways for SCCP contamination in the background area. The localized SCCP contamination could be derived from an unidentified source. Hierarchical cluster analysis indicated that C13- and C11-congeners were predominant in most soils and C10- and C12-congeners dominated in the remaining soils. Cl7- and Cl8-congeners were on the average the most dominant chlorine congeners in nearly all soils. Principal component analysis suggested that the separation of even and odd carbon chain congeners occurred during long-range atmospheric transport and aging in soil in the study area.

The blue man: burn from muriatic acid combined with chlorinated paint in an adult pool construction worker.

PubMed

O'Cleireachain, Marc R; Macias, Luis H; Richey, Karen J; Pressman, Melissa A; Shirah, Gina R; Caruso, Daniel M; Foster, Kevin N; Matthews, Marc R

2014-01-01

Muriatic acid (hydrochloric acid), a common cleaning and resurfacing agent for concrete pools, can cause significant burn injuries. When coating a pool with chlorinated rubber-based paint, the pool surface is initially cleansed using 31.45% muriatic acid. Here we report a 50-year-old Hispanic male pool worker who, during the process of a pool resurfacing, experienced significant contact exposure to a combination of muriatic acid and blue chlorinated rubber-based paint. Confounding the clinical situation was the inability to efficiently remove the chemical secondary to the rubber-based nature of the paint. Additionally, vigorous attempts were made to remove the rubber paint using a variety of agents, including bacitracin, chlorhexidine soap, GOOP adhesive, and Johnson's baby oil. Resultant injuries were devastating fourth-degree burns requiring an immediate operative excision and amputation. Despite aggressive operative intervention and resuscitation, he continued to have severe metabolic derangements and ultimately succumbed to his injuries. We present our attempts at debridement and the system in place to manage patients with complex chemical burns.

Nucleophilic substitution at centers other than carbon: reaction at the chlorine of N-chloroacetanilides with triethylamine as the nucleophile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Underwood, G.R.; Dietze, P.E.

1984-12-28

The reaction between triethylamine (TEA) and a series of para-substituted N-chloroacetanilides has been studied in aqueous solution buffered to pHs between 1 and 5. The exclusive product derived from the aromatic moiety is the corresponding acetanilide. The reaction occurs via two parallel pseudo-second-order paths, one acid catalyzed (the Orton-like mechanism), the other uncatalyzed. The uncatalyzed reaction is accelerated by the presence of electron-withdrawing substituents on the aromatic ring and can best be represented as nucleophilic displacement at chlorine. It therefore appears to be the prototype of a convenient class of reactions for the study of displacement reactions at chlorine. Themore » rho value for this reaction is 3.87, indicating substantial negative charge buildup in the aromatic ring during of the transition state. The acid-catalyzed reaction is more complex, presumable involving a protonation equilibrium for the N-chloroacetanilide prior to the rate-determining step similar to that in the Orton reaction. 15 references, 2 figures, 3 tables.« less

Pressure and phase dependence of the stereochemical course in hot tritium for hydrogen and chlorine-38 for chlorine substitution in meso- and rac-1,2-dichloro-1,2-difluoroethane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machulla, H J; Stocklin, G

1974-03-28

The pressure dependence of the stereochemical course in hot homolytic T- for-H and /sup 38/ Cl-for-Cl substitution in mesoand rac-1,2-dichloro-l,2- difluoroethane has been studied from 10 to 10/sup 4/ Torr. Distinct differences are observed between the yield vs. density dependence of the retained and the inverted product. For both recoil tritium and chlorine, substitution with inversion of configuration is almost negligible in the gas phase and its yields remained constant over the entire pressure range studied. Typical pressure effects are observed, however, for substitution with retention of configuration, particularly for recoil chlorine. While the change from the high-pressure gas phasemore » to the liquid leaves T-for-H substitution almost unaffected, /sup 38/Cl-for- Cl substitution exhibits a strong phase effect. The absolute yields of the retained product increase by a factor of 2.5, that of the invented product by about 20, almost identical in both diastereomeric substrates. The density dependence of the HCl and HF elimination products is also different for recoil tritium and chlorine; in the latter case the yields follow the increasing trend observed for substitution. While for recoil tritium the predominant substitution channel seems to be a direct replacement with retention of configuration, even in the liquid phase, /sup 38/Cl-for-Cl substitution at higher densities cannot be satisfactorily explained on the basis of the impact model nor by caged radical combination. Alternatively, substitution via a caged complex is discussed. (auth)« less

Evidence for Perchlorates and the Origin of Chlorinated Hydrocarbons Detected by SAM at the Rocknest Aeolian Deposit in Gale Crater

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Freissinet, Caroline; Miller, Kristen E.; Eigenbrode, Jennifer L.; Brunner, Anna E.; Buch, Arnaud; Sutter, Brad; Archer, P. Douglas, Jr.; Atreya, Sushil K.; Brinckerhoff, William B.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, M.A.; Cheng, C.W.; Kelley, K.P.

Process for converting alkenes to form epoxides utilizes transition metal nitro complexes of the formula: M(RCN)/sub 2/XNO/sub 2/ wherein M is palladium or platinum, R is an alkyl or aryl group containing up to 12 carbon atoms, and X is a monoanionic, monodentate ligand such as chlorine, optionally in the presence of molecular oxygen.

STABLE ASSOCIATION COMPLEX ELECTROSPRAY MASS SPECTROMETRY FOR THE DETERMINATION OF CYANURIC ACID

EPA Science Inventory

Cyanuric acid is a suspected gastrointestinal or liver toxicant in humans, and its long term effects on ecosystems are unknown. Cyanuric acid enters the environment in several ways. It is used as a chlorine stablilizer for recreational swimming pool waters. Because of its inheren...

Chloraminated Concentrated Drinking Water for Disinfection Byproduct Mixtures Research: Evaluating Free Chlorine Contact Times

EPA Science Inventory

Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) present in the source water. Since 1974, over 600 DBPs have been identified in drinking water, yet a large portio...

Preliminary conceptual models of the occurrence, fate, and transport of chlorinated solvents in karst regions of Tennessee

USGS Publications Warehouse

Wolfe, W.J.; Haugh, C.J.; Webbers, Ank; Diehl, T.H.

1997-01-01

Published and unpublished reports and data from 22 contaminated sites in Tennessee were reviewed to develop preliminary conceptual models of the behavior of chlorinated solvents in karst aquifers. Chlorinated solvents are widely used in many industrial operations. High density and volatility, low viscosity, and solubilities that are low in absolute terms but high relative to drinkingwater standards make chlorinated solvents mobile and persistent contaminants that are difficult to find or remove when released into the groundwater system. The major obstacle to the downward migration of chlorinated solvents in the subsurface is the capillary pressure of small openings. In karst aquifers, chemical dissolution has enlarged joints, bedding planes, and other openings that transmit water. Because the resulting karst conduits are commonly too large to develop significant capillary pressures, chlorinated solvents can migrate to considerable depth in karst aquifers as dense nonaqueous-phase liquids (DNAPL?s). Once chlorinated DNAPL accumulates in a karst aquifer, it becomes a source for dissolved-phase contamination of ground water. A relatively small amount of chlorinated DNAPL has the potential to contaminate ground water over a significant area for decades or longer. Conceptual models are needed to assist regulators and site managers in characterizing chlorinated-solvent contamination in karst settings and in evaluating clean-up alternatives. Five preliminary conceptual models were developed, emphasizing accumulation sites for chlorinated DNAPL in karst aquifers. The models were developed for the karst regions of Tennessee, but are intended to be transferable to similar karst settings elsewhere. The five models of DNAPL accumulation in karst settings are (1) trapping in regolith, (2) pooling at the top of bedrock, (3) pooling in bedrock diffuse-flow zones, (4) pooling in karst conduits, and (5) pooling in isolation from active ground-water flow. More than one conceptual model of DNAPL accumulation may be applicable to a given site, depending on details of the contaminant release and geologic setting. Trapping in regolith is most likely to occur where the regolith is thick and relatively impermeable with few large cracks, fissures, or macropores. Accumulation at the top of rock is favored by flat-lying strata with few fractures or karst features near the bedrock surface. Fractures or karst features near the bedrock surface encourage migration of chlorinated DNAPL into karst conduits or diffuse-flow zones in bedrock. DNAPL can migrate through one bedrock flow regime into an underlying flow regime with different characteristics or into openings that are isolated from significant ground-water flow. As a general rule, the difficulty of finding and removing DNAPL increases with depth, lateral distance from the source, and complexity of the ground-water flow system. The prospects for mitigation are generally best for DNAPL accumulation in the regolith or at the bedrock surface. However, many such accumulations are likely to be difficult to find or remove. Accumulations in bedrock diffuse-flow zones or in fractures isolated from flow may be possible to find and partially mitigate, but will likely leave significant amounts of contaminant in small fractures or as solute diffused into primary pores.

Inactivation of bacterial biothreat agents in water, a review.

PubMed

Rose, L J; Rice, E W

2014-12-01

Water supplies and water distribution systems have been identified as potential targets for contamination by bacterial biothreat agents. Since the 2001 Bacillus anthracis bioterrorist attacks, additional efforts have been aimed at research to characterize biothreat organisms in regards to their susceptibility to disinfectants and technologies currently in use for potable water. Here, we present a review of research relevant to disinfection of bacteria with the potential to pose a severe threat to public health and safety, and their potential surrogates. The efficacy of chlorine, monochloramine, chlorine dioxide, and ultraviolet light to inactivate each organism in suspension is described. The complexities of disinfection under varying water conditions and when the organisms are associated with biofilms in distribution systems are discussed.

Novel drug form of chlorin e6

NASA Astrophysics Data System (ADS)

Abakumova, O. Y.; Baum, Rudolf P.; Ermakova, Natalia Y.; Gradyushko, A. T.; Guseva-Donskaya, T. N.; Karmenyan, Artashes V.; Koraboyev, U. M.; Laptev, V. P.; Mechkov, V. M.; Mikhailova, L. M.; Panferova, N. G.; Rebeko, Aleksei G.; Reshetnickov, Andrei V.; Ryabov, M. V.; Stranadko, Eugeny P.; Tsvetkova, Tatyana A.; Zhukova, O. S.

1999-12-01

A novel stable water-soluble form of well known photosensitizer chlorin e6 named `Photodithazine' has been obtained from Spirulina Platensis cyanobacteria as a noncovalent complex with N-methyl-D-glucosamine, and its biological characteristics evaluate, which proved to be as follows: in vitro photocytotoxicity was 1 (mu) M (EC50) as determined by the extent of DNA synthesis inhibition in CaOv cells after irradiation with 650 - 900 nm light, and 5 (mu) M (EC65) as determined using MTT test on PC12 cells after irradiation with 670 nm laser light at the doses of 15 and 20 J/cm2, respectively, with Al-sulfophthalocyanine `Photosense' (Russia; oligomerized hematoporphyrin-IX mixture `Photogen', Russia) being used as permitted reference drugs.

Inactivation of bacterial biothreat agents in water, a review

PubMed Central

Rice, E. W.

2016-01-01

Water supplies and water distribution systems have been identified as potential targets for contamination by bacterial biothreat agents. Since the 2001 Bacillus anthracis bioterrorist attacks, additional efforts have been aimed at research to characterize biothreat organisms in regards to their susceptibility to disinfectants and technologies currently in use for potable water. Here, we present a review of research relevant to disinfection of bacteria with the potential to pose a severe threat to public health and safety, and their potential surrogates. The efficacy of chlorine, monochloramine, chlorine dioxide, and ultraviolet light to inactivate each organism in suspension is described. The complexities of disinfection under varying water conditions and when the organisms are associated with biofilms in distribution systems are discussed. PMID:25473971

Evaluating potential chlorinated methanes degradation mechanisms and treatments in interception trenches filled with concrete-based construction wastes

NASA Astrophysics Data System (ADS)

Rodríguez-Fernandez, Diana; Torrentó, Clara; Rosell, Mònica; Audí-Miró, Carme; Soler, Albert

2014-05-01

A complex mixture of chlorinated organic compounds is located in an unconfined carbonated bedrock aquifer with low permeability in a former industrial area next to Barcelona (NE Spain). The site exhibited an especially high complexity due to the presence of multiple contaminant sources, wide variety of pollutants (mainly chlorinated ethenes but also chlorinated methanes) and unknown system of fractures (Palau et al., 2014). Interception trenches were installed in the place of the removed pollution sources and were filled with construction wastes with the aim of retaining and treating the accumulated contaminated recharge water before reaching the aquifer. Recycled concrete-based aggregates from a construction and demolition waste recycling plant were used to maintain alkaline conditions in the water accumulated in the trenches (pH 11.6±0.3) and thus induce chloroform (CF) degradation by alkaline hydrolysis. An efficacy of around 30-40% CF degradation in the interception trenches was calculated from the significant and reproducible CF carbon isotopic fractionation (-53±3o obtained in batch experiments (Torrentó et al., 2014). Surprisingly, although hydrolysis of carbon tetrachloride (CT) is extremely slow, a significant CT carbon isotopic enrichment was also observed in the trenches. The laboratory experiments verified the low capability of concrete to hydrolyze the CT and showed the high adsorption of CT on the concrete particles (73% after 50 days) with invariability in its δ13C values. Therefore, the significant CT isotopic fractionation observed in the interception trenches could point out the occurrence of other degradation processes distinct than alkaline hydrolysis. Geochemical speciation modelling using the code PHREEQC showed that water collected at the trenches is supersaturated with respect to several iron oxy-hydroxides and therefore, CT degradation processes related to these iron minerals cannot be discarded. In addition, the combination of alkaline conditions in the trenches with in situ chemical oxidation (ISCO), which would be able to remove the rest of the accompanying pollutants, is proposed and merits evaluation. Preliminary batch experiments were performed to evaluate the feasibility of different chemical oxidation reactions (permanganate, persulphate, hydrogen peroxide and Fenton) on the complex contaminated recharge water which were, in general, more effective for degrading the chlorinated ethenes than for the chlorinated methanes (Torrentó et al. EGU 2012). Therefore, this study seeks to improve the understanding of CF and CT degradation mechanisms/processes that are going on in the interception trenches as well as to select between the two most effective chemical oxidation remediation treatments (persulphate and permanganate) taking into account their efficiency respect the chlorinated methanes removal, the generated acute toxicity and the applicability of the carbon isotopic fractionation as an indicator of the effectiveness of the future in situ remediation. Additionally, ongoing batch experiments are expected to elucidate if CT is undergoing abiotic reductive dechlorination by Fe-bearing minerals such as hydrophobic green rust (Ayala-Luis et al., 2012) which transform CT into non-chlorinated substances such as formic acid and carbon monoxide. This unstable iron compound might be formed in the interception trenches during chloride induced corrosion of iron mineral phases present in the concrete-based construction wastes (Sagoe-Crentsil and Glasser, 1993). The role of other minerals like iron oxy-hydroxides, carbonates or sulphides cannot be discarded at all. The potential of δ13C values to assess the efficiency of this abiotic CT degradation reaction will be also evaluated. References Ayala-Luis, K.; Cooper, N.; Bender C. and Hansen. H. (2012) Efficient dechlorination of carbon tetrachloride by hydrophobic green rust intercaled with dodecanoate anions. Environmental Science & Technology 46, 3390-3397. Palau, J.; Marchesi, M.: Chambon, J.: Aravena, R.; Canals, A.; Binning, P. J., Bjerg P. L.; Otero, N.; Soler, A. (2014) Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes. Science of the Total Environment 475, 61-70. Sagoe-Crentsil, K.K.; Glasser, F.P. (1993) 'Green Rust', Iron Solubility and the Role of Chloride in the Corrosion of Steel at High pH,' Cement and Concrete Research, 23(4), 785-91. Torrentó, C., Audí-Miró, C., Marchesi, M., Otero, N. and Soler, A. (2012) Comparison of four oxidation processes for the treatment of water contaminated with a mixture of chlorinated volatile organic compounds. EGU General Assembly 2012. Vienna. Geophysical Research Abstracts, 14: EGU2012-11310. Torrentó, C.; Audí-Miró, C.; Bordeleau, G.; Marchesi, M.; Rosell, M.; Otero, N.; Soler, A. (2014) The use of alkaline hydrolysis as a novel strategy for chloroform remediation: the feasibility of using construction wastes and evaluation of carbon isotopic fractionation. Environmental Science & Technology, Just Accepted Manuscript (DOI: 10.1021/es403838t)

The geochemistry of fluids from an active shallow submarine hydrothermal system: Milos island, Hellenic Volcanic Arc

NASA Astrophysics Data System (ADS)

Valsami-Jones, E.; Baltatzis, E.; Bailey, E. H.; Boyce, A. J.; Alexander, J. L.; Magganas, A.; Anderson, L.; Waldron, S.; Ragnarsdottir, K. V.

2005-10-01

Geothermal activity in the Aegean island of Milos (Greece), associated with island-arc volcanism, is abundant both on-and off-shore. Hydrothermal fluids venting from several sites, mainly shallow submarine (up to 10 m), but also just above seawater level in one locality, were sampled over four summer field seasons. Some of the discharging fluids are associated with the formation of hydrothermal edifices. Overall, the main characteristics of the hydrothermal fluids are low pH and variable chlorinity. The lowest recorded pH was 1.7, and chlorinity ranged from 0.1 to 2.5 times that of seawater. The highest fluid temperatures recorded on site were 115 °C. Two main types of fluids were identified: low-chlorinity fluids containing low concentrations of alkalis (potassium, lithium, sodium) and calcium, and high concentrations of silica and sulphate; and high-chlorinity fluids containing high concentrations of alkalis and calcium, and lower concentrations of silica and sulphate. The type locality of the high-chlorinity fluids is shallow submarine in Palaeochori, near the east end of the south coast of the island, whereas the type locality of the low-chlorinity fluids is a cave to the west of Palaeochori. The two fluid types are therefore often referred to as "submarine" and "cave" fluids respectively. Both fluid types had low magnesium and high metal concentrations but were otherwise consistently different from each other. The low-chlorinity fluids had the highest cobalt, nickel, aluminium, iron and chromium (up to 1.6 μM, 3.6 μM, 1586 μM, 936 μM and 3.0 μM, respectively) and the high-chlorinity fluids had the highest zinc, cadmium, manganese and lead (up to 4.1 μM, 1.0 μM, 230 μM and 32 μM, respectively). Geochemical modelling suggests that metals in the former are likely to have been transported as sulphate species or free ions and in the latter as chloride species or free ions. Isotopic values for both water types range between δD -12 to 33‰ and δ 18O 1.2 to 4.6‰. The range of fluid compositions and isotopic contents indicates a complex history of evolution for the system. Both types of fluids appear to be derived from seawater and thus are likely to represent end members of a single fluid phase that underwent phase separation at depth.

Simultaneous control of microorganisms and disinfection by-products by sequential chlorination.

PubMed

Chen, Chao; Zhang, Xiao-Jian; He, Wen-Jie; Han, Hong-Da

2007-04-01

To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Pilot tests of this sequential chlorination were carried out in a drinking water plant. The sequential chlorination disinfection process had the same or better efficiency on microbe (including virus) inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process. The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination. This process takes advantages of free chlorine's quick inactivation of microorganisms and chloramine's low disinfection by-product (DBP) yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.

Two-step chlorination: A new approach to disinfection of a primary sewage effluent.

PubMed

Li, Yu; Yang, Mengting; Zhang, Xiangru; Jiang, Jingyi; Liu, Jiaqi; Yau, Cie Fu; Graham, Nigel J D; Li, Xiaoyan

2017-01-01

Sewage disinfection aims at inactivating pathogenic microorganisms and preventing the transmission of waterborne diseases. Chlorination is extensively applied for disinfecting sewage effluents. The objective of achieving a disinfection goal and reducing disinfectant consumption and operational costs remains a challenge in sewage treatment. In this study, we have demonstrated that, for the same chlorine dosage, a two-step addition of chlorine (two-step chlorination) was significantly more efficient in disinfecting a primary sewage effluent than a one-step addition of chlorine (one-step chlorination), and shown how the two-step chlorination was optimized with respect to time interval and dosage ratio. Two-step chlorination of the sewage effluent attained its highest disinfection efficiency at a time interval of 19 s and a dosage ratio of 5:1. Compared to one-step chlorination, two-step chlorination enhanced the disinfection efficiency by up to 0.81- or even 1.02-log for two different chlorine doses and contact times. An empirical relationship involving disinfection efficiency, time interval and dosage ratio was obtained by best fitting. Mechanisms (including a higher overall Ct value, an intensive synergistic effect, and a shorter recovery time) were proposed for the higher disinfection efficiency of two-step chlorination in the sewage effluent disinfection. Annual chlorine consumption costs in one-step and two-step chlorination of the primary sewage effluent were estimated. Compared to one-step chlorination, two-step chlorination reduced the cost by up to 16.7%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chlorination Revisited: Does Cl- Serve as a Catalyst in the Chlorination of Phenols?

PubMed

Lau, Stephanie S; Abraham, Sonali M; Roberts, A Lynn

2016-12-20

The aqueous chlorination of (chloro)phenols is one of the best-studied reactions in the environmental literature. Previous researchers have attributed these reactions to two chlorine species: HOCl (at circum-neutral and high pH) and H 2 OCl + (at low pH). In this study, we seek to examine the roles that two largely overlooked chlorine species, Cl 2 and Cl 2 O, may play in the chlorination of (chloro)phenols. Solution pH, chloride concentration, and chlorine dose were systematically varied in order to assess the importance of different chlorine species as chlorinating agents. Our findings indicate that chlorination rates at pH < 6 increase substantially when chloride is present, attributed to the formation of Cl 2 . At pH 6.0 and a chlorine dose representative of drinking water treatment, Cl 2 O is predicted to have at best a minor impact on chlorination reactions, whereas Cl 2 may contribute more than 80% to the overall chlorination rate depending on the (chloro)phenol identity and chloride concentration. While it is not possible to preclude H 2 OCl + as a chlorinating agent, we were able to model our low-pH data by considering Cl 2 only. Even traces of chloride can generate sufficient Cl 2 to influence chlorination kinetics, highlighting the role of chloride as a catalyst in chlorination reactions.

40 CFR 704.45 - Chlorinated terphenyl.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chlorinated terphenyl. 704.45 Section....45 Chlorinated terphenyl. (a) Definitions. (1) Chlorinated terphenyl means a chemical substance, CAS No. 61788-33-6, comprised of chlorinated ortho-, meta-, and paraterphenyl. (2) Extent of chlorination...

Temperature Dependence of Gas Properties in Polynomial Form

DTIC Science & Technology

1981-01-01

Carbonyl Sulfide Chlorine Chlorine (Monatomic) Chlorine Dioxide Chlorine Fluoride Chlorine Monoxide Chlorine Oxide Chlorine Trifluoride ...dis- cussed in Section 5 and the following eqn: 100-1500K~ Cp(T)= 515.3754 + 0.426933T -2.91036E-04T 2 -+ 6.836113E-08Ti CHLORINE TRIFLUORIDE C1F 3...3 Trimeric Boron Tribromide BBr3 250.538 33.186 A-3 Boron Trichloride BC1 3 117.170 70.959 A-4 Boron Trifluoride BF3 67.806 122.619 A-4 Bromine Br2

Reductive amination with zinc powder in aqueous media

PubMed Central

Imperio, Daniela; Penoni, Andrea; Palmisano, Giovanni

2011-01-01

Summary Zinc powder in aqueous alkaline media was employed to perform reductive amination of aldehydes with primary amines. The corresponding secondary amines were obtained in good yields along with minor amounts of hydrodimerization byproducts. The protocol is a green alternative to the use of complex hydrides in chlorinated or highly flammable solvents. PMID:21915212

Assessment of reproductive effects on complex mixtures of disinfection by-products in a multigenerational rat bioassay of drinking water concentrates

EPA Science Inventory

To address concerns raised by epidemiology studies, we conducted a multigenerational reproductive toxicity study in rats using a “whole” mixture of drinking water disinfection by-products (DBPs). Raw water was concentrated ~130 fold, chlorinated, and provided as drinking water to...

Assessment of Reproductive Effects of Complex Mixtures of Disinfection By-Products in a Multi-Generational Rat Bioassay of Drinking Water Concentrates - Monterey

EPA Science Inventory

To address concerns raised by epidemiology studies, we conducted a multigenerational reproductive toxicity study in rats using a “whole” mixture of drinking water disinfection by-products (DBPs). Raw water was concentrated ~130 fold, chlorinated, and provided as drinking water to...

Fate of free chlorine in drinking water during distribution in premise plumbing.

PubMed

Zheng, Muzi; He, Chunguang; He, Qiang

2015-12-01

Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of pipe deposits. In contrast, the impact on chlorine decay by pipe deposits was not significant in galvanized iron and PVC pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise plumbing.

Optimal design and management of chlorination in drinking water networks: a multi-objective approach using Genetic Algorithms and the Pareto optimality concept

NASA Astrophysics Data System (ADS)

Nouiri, Issam

2017-11-01

This paper presents the development of multi-objective Genetic Algorithms to optimize chlorination design and management in drinking water networks (DWN). Three objectives have been considered: the improvement of the chlorination uniformity (healthy objective), the minimization of chlorine booster stations number, and the injected chlorine mass (economic objectives). The problem has been dissociated in medium and short terms ones. The proposed methodology was tested on hypothetical and real DWN. Results proved the ability of the developed optimization tool to identify relationships between the healthy and economic objectives as Pareto fronts. The proposed approach was efficient in computing solutions ensuring better chlorination uniformity while requiring the weakest injected chlorine mass when compared to other approaches. For the real DWN studied, chlorination optimization has been crowned by great improvement of free-chlorine-dosing uniformity and by a meaningful chlorine mass reduction, in comparison with the conventional chlorination.

The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

PubMed

Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

2016-08-01

Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

Key Factors Controlling the Applicability and Efficiency of Bioremediation of Chlorinated Ethenes In Situ

NASA Astrophysics Data System (ADS)

Zhang, M.; Yoshikawa, M.; Takeuchi, M.; Komai, T.

2012-12-01

Bioremediation has been considered as one of environmentally friendly and cost effective approaches for cleaning up the sites polluted by organic contaminants, such as chlorinated ethenes. Although bioremediation, in its widest sense, is not new, and many researches have been performed on bioremediation of different kinds of pollutants, an effective design and implication of in situ bioremediation still remains a challenging problem because of the complexity. Many factors may affect the applicability and efficiency of bioremediation of chlorinated ethenes in situ, which include the type and concentration of contaminants, biological, geological and hydro-geological conditions of the site, physical and chemical characteristics of groundwater and soils to be treated, as well as the constraints in engineering. In this presentation, an overview together with a detailed discussion on each factor will be provided. The influences of individual factors are discussed using the data obtained or cited from different sites and experiments, and thus under different environmental conditions. The results of this study illustrated that 1) the establishment of microbial consortium is of crucial importance for a complete degradation of chlorinated ethenes, 2) in situ control of favorable conditions for increasing microbial activities for bio-degradation through a designed pathway is the key to success, 3) the focus of a successful remediation system is to design an effective delivery process that is capable of producing adequate amendment mixing of contaminant-degrading bacteria, appropriate concentrations of electron acceptors, electron donors, and microbial nutrients in the subsurface treatment area.

Effects of chlorinated drinking water on the xenobiotic metabolism in Cyprinus carpio treated with samples from two Italian municipal networks.

PubMed

Cirillo, Silvia; Canistro, Donatella; Vivarelli, Fabio; Paolini, Moreno

2016-09-01

Drinking water (DW) disinfection represents a milestone of the past century, thanks to its efficacy in the reduction of risks of epidemic forms by water micro-organisms. Nevertheless, such process generates disinfection by-products (DBPs), some of which are genotoxic both in animals and in humans and carcinogenic in animals. At present, chlorination is one of the most employed strategies but the toxicological effects of several classes of DBPs are unknown. In this investigation, a multidisciplinary approach foreseeing the chemical analysis of chlorinated DW samples and the study of its effects on mixed function oxidases (MFOs) belonging to the superfamily of cytochrome P450-linked monooxygenases of Cyprinus carpio hepatopancreas, was employed. The experimental samples derived from aquifers of two Italian towns (plant 1, river water and plant 2, spring water) were obtained immediately after the disinfection (A) and along the network (R1). Animals treated with plant 1 DW-processed fractions showed a general CYP-associated MFO induction. By contrast, in plant 2, a complex modulation pattern was achieved, with a general up-regulation for the point A and a marked MFO inactivation in the R1 group, particularly for the testosterone metabolism. Together, the toxicity and co-carcinogenicity (i.e. unremitting over-generation of free radicals and increased bioactivation capability) of DW linked to the recorded metabolic manipulation, suggests that a prolonged exposure to chlorine-derived disinfectants may produce adverse health effects.

Control of mineral scale deposition in cooling systems using secondary-treated municipal wastewater.

PubMed

Li, Heng; Hsieh, Ming-Kai; Chien, Shih-Hsiang; Monnell, Jason D; Dzombak, David A; Vidic, Radisav D

2011-01-01

Secondary-treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. A prominent challenge for the successful use of MWW for cooling is potentially severe mineral deposition (scaling) on pipe surfaces. In this study, theoretical, laboratory, and field work was conducted to evaluate the mineral deposition potential of MWW and its deposition control strategies under conditions relevant to power plant cooling systems. Polymaleic acid (PMA) was found to effectively reduce scale formation when the makeup water was concentrated four times in a recirculating cooling system. It was the most effective deposition inhibitor of those studied when applied at 10 mg/L dosing level in a synthetic MWW. However, the deposition inhibition by PMA was compromised by free chlorine added for biogrowth control. Ammonia present in the wastewater suppressed the reaction of the free chlorine with PMA through the formation of chloramines. Monochloramine, an alternative to free chlorine, was found to be less reactive with PMA than free chlorine. In pilot tests, scaling control was more challenging due to the occurrence of biofouling even with effective control of suspended bacteria. Phosphorous-based corrosion inhibitors are not appropriate due to their significant loss through precipitation reactions with calcium. Chemical equilibrium modeling helped with interpretation of mineral precipitation behavior but must be used with caution for recirculating cooling systems, especially with use of MWW, where kinetic limitations and complex water chemistries often prevail. Copyright © 2010 Elsevier Ltd. All rights reserved.

Importance of chlorine speciation on de novo formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans.

PubMed

Wikström, Evalena; Ryan, Shawn; Touati, Abderrahmane; Telfer, Marnie; Tabor, Dennis; Gullett, Brian K

2003-03-15

The role of chlorine speciation on de novo formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) has been studied thoroughly in an entrained flow reactor during simulated waste combustion. The effects of gas-phase chlorine species such as chlorine (Cl2), hydrogen chloride (HCl), and chlorine radicals (Cl*), as well as ash-bound chlorine, on PCDD/F de novo formation were isolated for investigation. The ash-bound chlorine alone was observed to be a sufficient chlorine source for PCDD/F formation. The addition of HCl to the system did not influence the yields of the PCDDs/Fs nor the degree of chlorination due to its poor chlorinating ability. Addition of 200 ppm of Cl2 to the ash-feed system resulted in increased PCDD/F yields, especially for the octa- and hepta-chlorinated congeners. Altering the reaction temperature to enable the presence of only Cl2 to the system did not change the yields of PCDD/F compared to those when both Cl2/Cl* were present. However, comparison between ash-bound and gas-phase chlorine, the latter at a concentration typical of a realistic combustion process, revealed ash-bound chlorine to be the more important chlorine source for de novo formation of PCDD/F in a full-scale incinerator.

Three-step effluent chlorination increases disinfection efficiency and reduces DBP formation and toxicity.

PubMed

Li, Yu; Zhang, Xiangru; Yang, Mengting; Liu, Jiaqi; Li, Wanxin; Graham, Nigel J D; Li, Xiaoyan; Yang, Bo

2017-02-01

Chlorination is extensively applied for disinfecting sewage effluents, but it unintentionally generates disinfection byproducts (DBPs). Using seawater for toilet flushing introduces a high level of bromide into domestic sewage. Chlorination of sewage effluent rich in bromide causes the formation of brominated DBPs. The objectives of achieving a disinfection goal, reducing disinfectant consumption and operational costs, as well as diminishing adverse effects to aquatic organisms in receiving water body remain a challenge in sewage treatment. In this study, we have demonstrated that, with the same total chlorine dosage, a three-step chlorination (dosing chlorine by splitting it into three equal portions with a 5-min time interval for each portion) was significantly more efficient in disinfecting a primary saline sewage effluent than a one-step chlorination (dosing chlorine at one time). Compared to one-step chlorination, three-step chlorination enhanced the disinfection efficiency by up to 0.73-log reduction of Escherichia coli. The overall DBP formation resulting from one-step and three-step chlorination was quantified by total organic halogen measurement. Compared to one-step chlorination, the DBP formation in three-step chlorination was decreased by up to 23.4%. The comparative toxicity of one-step and three-step chlorination was evaluated in terms of the development of embryo-larva of a marine polychaete Platynereis dumerilii. The results revealed that the primary sewage effluent with three-step chlorination was less toxic than that with one-step chlorination, indicating that three-step chlorination could reduce the potential adverse effects of disinfected sewage effluents to aquatic organisms in the receiving marine water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a Chlorine Dosing Strategy for Fresh Produce Washing Process to Maintain Microbial Food Safety and Minimize Residual Chlorine.

PubMed

Chen, Xi; Hung, Yen-Con

2018-06-01

The residual free chlorine level in fresh produce wash solution is closely correlated to the chemical and microbial safety of produce. Excess amount of free chlorine can quickly react with organic matters to form hazardous disinfection by-products (DBPs) above EPA-permitted levels, whereas deficiency of residual chlorine in produce wash solution may result in incompletely removing pathogens on produce. The purpose of this study was to develop a chlorine dosing strategy to optimize the chlorine dosage during produce washing process without impacting the microbial safety of fresh produce. Prediction equations were developed to estimate free chlorine needed to reach targeted residual chlorine at various sanitizer pH and organic loads, and then validated using fresh-cut iceberg lettuce and whole strawberries in an automated produce washer. Validation results showed that equations successfully predicted the initial chlorine concentration needed to achieve residual chlorine at 10, 30, 60, and 90 mg/L for both lettuce and strawberry washing processes, with the root mean squared error at 4.45 mg/L. The Escherichia coli O157:H7 reductions only slightly increased on iceberg lettuce and strawberries with residual chlorine increasing from 10 to 90 mg/L, indicating that lowering residual chlorine to 10 mg/L would not compromise the antimicrobial efficacy of chlorine-based sanitizer. Based on the prediction equations and E. coli O157:H7 reduction results, a chlorine dosing strategy was developed to help the produce industry to maintain microbial inactivation efficacy without adding excess amount of free chlorine. The chlorine dosing strategy can be used for fresh produce washing process to enhance the microbial food safety and minimize the DBPs formation potential. © 2018 Institute of Food Technologists®.

Using the nuclear activation AMS method for determining chlorine in solids at ppb-levels and below

NASA Astrophysics Data System (ADS)

Winkler, Stephan R.; Eigl, Rosmarie; Forstner, Oliver; Martschini, Martin; Steier, Peter; Sterba, Johannes H.; Golser, Robin

2015-10-01

Neutron activation analysis using decay counting of the activated element is a well-established method in elemental analysis. However, for chlorine there is a better alternative to measuring decay of the short-lived activation product chlorine-38 (t1/2 = 37.24 min) - accelerator mass spectrometry (AMS) of 36Cl: the relatively high neutron capture cross section of chlorine-35 for thermal neutrons (43.7 b) and combined the AMS technique for chlorine-36 (t1/2 = 301 ka) allow for determination of chlorine down to ppb-levels using practical sample sizes and common exposure durations. The combination of neutron activation and AMS can be employed for a few other elements (nitrogen, thorium, and uranium) as well. For bulk solid samples an advantage of the method is that lab contamination can be rendered irrelevant. The chlorine-35 in the sample is activated to chlorine-36, and surface chlorine can be removed after the irradiation. Subsequent laboratory contamination, however, will not carry a prominent chlorine-36 signature. After sample dissolution and addition of sufficient amounts of stable chlorine carrier the produced chlorine-36 and thus the original chlorine-35 of the sample can be determined using AMS. We have developed and applied the method for analysis of chlorine in steel samples. The chlorine content of steel is of interest to nuclear industry, precisely because of above mentioned high neutron capture cross section for chlorine-35, which leads to accumulation of chlorine-36 as long-term nuclear waste. The samples were irradiated at the TRIGA Mark II reactor of the Atominstitut in Vienna and the 36Cl-AMS setup at the Vienna Environmental Research Accelerator (VERA) was used for 36Cl/Cl analysis.

Full-scale studies of factors related to coliform regrowth in drinking water.

PubMed

LeChevallier, M W; Welch, N J; Smith, D B

1996-07-01

An 18-month survey of 31 water systems in North America was conducted to determine the factors that contribute to the occurrence of coliform bacteria in drinking water. The survey included analysis of assimilable organic carbon (AOC), coliforms, disinfectant residuals, and operational parameters. Coliform bacteria were detected in 27.8% of the 2-week sampling periods and were associated with the following factors: filtration, temperature, disinfectant type and disinfectant level, AOC level, corrosion control, and operational characteristics. Four systems in the study that used unfiltered surface water accounted for 26.6% of the total number of bacterial samples collected but 64.3% (1,013 of 1,576) of the positive coliform samples. The occurrence of coliform bacteria was significantly higher when water temperatures were > 15 degrees C. For filtered systems that used free chlorine, 0.97% of 33,196 samples contained coliform bacteria, while 0.51% of 35,159 samples from chloraminated systems contained coliform bacteria. The average density of coliform bacteria was 35 times higher in free-chlorinated systems than in chloraminated water (0.60 CFU/100 ml for free-chlorinated water compared with 0.017 CFU/100 ml for chloraminated water). Systems that maintained dead-end free chlorine levels of < 0.2 mg/liter or monochloramine levels of < 0.5 mg/liter had substantially more coliform occurrences than systems that maintained higher disinfectant residuals. Free-chlorinated systems with AOC levels greater than 100 micrograms/liter had 82% more coliform-positive samples and 19 times higher coliform levels than free-chlorinated systems with average AOC levels less than 99 micrograms/liter. Systems that maintained a phosphate-based corrosion inhibitor and limited the amount of unlined cast iron pipe had fewer coliform bacteria. Several operational characteristics of the treatment process or the distribution system were also associated with increased rates of coliform occurrence. The study concludes that the occurrence of coliform bacteria within a distribution system is dependent upon a complex interaction of chemical, physical, operational, and engineering parameters. No one factor could account for all of the coliform occurrences, and one must consider all of the parameters described above in devising a solution to the regrowth problem.

Full-scale studies of factors related to coliform regrowth in drinking water.

PubMed Central

LeChevallier, M W; Welch, N J; Smith, D B

1996-01-01

An 18-month survey of 31 water systems in North America was conducted to determine the factors that contribute to the occurrence of coliform bacteria in drinking water. The survey included analysis of assimilable organic carbon (AOC), coliforms, disinfectant residuals, and operational parameters. Coliform bacteria were detected in 27.8% of the 2-week sampling periods and were associated with the following factors: filtration, temperature, disinfectant type and disinfectant level, AOC level, corrosion control, and operational characteristics. Four systems in the study that used unfiltered surface water accounted for 26.6% of the total number of bacterial samples collected but 64.3% (1,013 of 1,576) of the positive coliform samples. The occurrence of coliform bacteria was significantly higher when water temperatures were > 15 degrees C. For filtered systems that used free chlorine, 0.97% of 33,196 samples contained coliform bacteria, while 0.51% of 35,159 samples from chloraminated systems contained coliform bacteria. The average density of coliform bacteria was 35 times higher in free-chlorinated systems than in chloraminated water (0.60 CFU/100 ml for free-chlorinated water compared with 0.017 CFU/100 ml for chloraminated water). Systems that maintained dead-end free chlorine levels of < 0.2 mg/liter or monochloramine levels of < 0.5 mg/liter had substantially more coliform occurrences than systems that maintained higher disinfectant residuals. Free-chlorinated systems with AOC levels greater than 100 micrograms/liter had 82% more coliform-positive samples and 19 times higher coliform levels than free-chlorinated systems with average AOC levels less than 99 micrograms/liter. Systems that maintained a phosphate-based corrosion inhibitor and limited the amount of unlined cast iron pipe had fewer coliform bacteria. Several operational characteristics of the treatment process or the distribution system were also associated with increased rates of coliform occurrence. The study concludes that the occurrence of coliform bacteria within a distribution system is dependent upon a complex interaction of chemical, physical, operational, and engineering parameters. No one factor could account for all of the coliform occurrences, and one must consider all of the parameters described above in devising a solution to the regrowth problem. PMID:8779557

Formation of halogenated organics during waste-water disinfection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, P.C.; Brown, R.A.; Wiseman, J.F.

The research examined the formation of trihalomethanes (THMs) and total organic halides (TOX) during wastewater chlorination at three wastewater treatment plants in the central Piedmont of North Carolina. Secondary effluent samples were collected before and after the addition of chlorine at each of the three treatment facilities; chlorinated samples were taken from various locations within the chlorine contact chambers and at the plant discharge. Water samples were also collected upstream and downstream from two of the plant outfalls to determine the increase and persistence of THMs and TOX below each plant. TOX and THM formation was evaluated in terms ofmore » effluent wastewater quality (e.g., residual chemical oxygen demand, total organic carbon and ammonia concentration), chlorine dose, chlorine contacting system, methods of chlorine addition, and chlorine-to-ammonia ratio. The results showed that TOX was present in the unchlorinated wastewater and that additional TOX was formed immediately after chlorine addition. Small to insignificant amounts of THMS were detected. TOX formation did not increase with increasing contact time, due to the rapid depletion of free chlorine and the formation of combined chlorine in the chlorine contact chamber.« less

Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: Mass balance, PCR and compound-specific stable isotope analysis

NASA Astrophysics Data System (ADS)

Courbet, Christelle; Rivière, Agnès; Jeannottat, Simon; Rinaldi, Sandro; Hunkeler, Daniel; Bendjoudi, Hocine; de Marsily, Ghislain

2011-11-01

This work describes the use of different complementing methods (mass balance, polymerase chain reaction assays and compound-specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent-contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at various times in the past, it is not enough to analyze chlorinated solvent concentrations along a flow path to convincingly demonstrate biodegradation. Moreover, only a few data were initially available to characterize the geochemical conditions at this site, which were apparently complex at the source zone due to (i) the presence of a steady oxygen supply to the groundwater by irrigation canal losses and river infiltration and (ii) an alkaline pH higher than 10 due to former underground lime disposal. A demonstration of the existence of biodegradation processes was however required by the regulatory authority within a timeframe that did not allow a full geochemical characterization of such a complex site. Thus a combination of different fast methods was used to obtain a proof of the biodegradation occurrence. First, a mass balance analysis was performed which revealed the existence of a strong natural attenuation process (biodegradation, volatilization or dilution), despite the huge uncertainty on these calculations. Second, a good agreement was found between carbon isotopic measurements and PCR assays (based on 16S RNA gene sequences and functional genes), which clearly indicated reductive dechlorination of different hydrocarbons (Tetrachloroethene—PCE-, Trichloroethene—TCE-, 1,2- cisDichloroethene— cis-1,2-DCE-, 1,2- transDichloroethene— trans-1,2-DCE-, 1,1-Dichloroethene—1,1-DCE-, and Vinyl Chloride—VC) to ethene. According to these carbon isotope measurements, although TCE biodegradation seems to occur only in the upgradient part of the studied zone, DCE and VC dechlorination (originating from the initial TCE dechlorination) occurs along the entire flowpath. TCE reductase was not detected among the Dehalococcoides bacteria identified by quantitative PCR (qPCR), while DCE and VC reductases were present in the majority of the population. Reverse transcriptase PCR assays (rt-PCR) also indicated that bacteria and their DCE and VC reductases were active. Mass balance calculations showed moreover that 1,1-DCE was the predominant DCE isomer produced by TCE dechlorination in the upgradient part of the site. Consequently, coupling rt-PCR assays with isotope measurements removes the uncertainties inherent in a simple mass balance approach, so that when the three methods are used jointly, they allow the identification and quantification of natural biodegradation, even under apparently complex geochemical and hydraulic conditions.

How effective is intermittent chlorination to control adult mussel fouling in cooling water systems?

PubMed

Rajagopal, Sanjeevi; Van der Velde, Gerard; Van der Gaag, Marinus; Jenner, Henk A

2003-01-01

Mussel control in cooling water systems is generally achieved by means of chlorination. Chlorine is applied continuously or intermittently, depending on cost and discharge criteria. In this paper, we examined whether mussels will be able to survive intermittent chlorination because of their ability to close their valves during periods of chlorination. Experiments were carried out using three common species of mussels: a freshwater mussel, Dreissena polymorpha, a brackish water mussel, Mytilopsis leucophaeata and a marine mussel, Mytilus edulis. The mussels were subjected to continuous or intermittent (4 h chlorination followed by 4 h no chlorination) chlorination at concentrations varying from 1 to 3 mg l(-1) and their responses (lethal and sublethal) were compared to those of control mussels. In addition, shell valve activity of mussels was monitored using a Mussel-monitor. Data clearly indicate that mussels shut their valves as soon as chlorine is detected in the environment and open only after chlorine dosing is stopped. However, under continuous chlorination mussels are constrained to keep the shell valves shut continuously. The mussels subjected to continuous chlorination at 1 mg l(-1) showed 100% mortality after 588 h (D. polymorpha), 966 h (Mytilus edulis) and 1104 h (Mytilopsis leucophaeata), while those subjected to intermittent chlorination at 1 mg l(-1) showed very little or no mortality during the same periods. Filtration rate, foot activity index and shell valve movement of D. polymorpha, Mytilopsis leucophaeata and Mytilus edulis decreased more than 90% at 1 mg l(-1) chlorine residual when compared to control. However, mussels subjected to intermittent chlorination showed a similar reduction (about 90%) in filtration rate, foot activity index and shell valve movement during chlorination and 3% during breaks in chlorination. The data indicate that intermittent chlorination between 1 and 3 mg l(-1) applied at 4 h on and 4 h off cycle is unlikely to control biofouling if mussels are the dominant fouling organisms.

Chlorine Isotopes: As a Possible Tracer of Fluid/Bio-Activities on Mars and a Progress Report on Chlorine Isotope Analysis by TIMs

NASA Technical Reports Server (NTRS)

Nakamura, N.; Nyquist, L.E.; Reese, Y.; Shih, C-Y.; Numata, M.; Fujitani, T.; Okano, O.

2009-01-01

Significantly large mass fractionations between chlorine isotopes (Cl-35, Cl-37) have been reported for terrestrial materials including both geological samples and laboratory materials. Also, the chlorine isotopic composition can be used as a tracer for early solar system processes. Moreover, chlorine is ubiquitous on the Martian surface. Typical chlorine abundances in Gusev soils are approx.0.5 %. The global surface average chlorine abundance also is approx.0.5 %. Striking variations among outcrop rocks at Meridiani were reported with some chlorine abundances as high as approx.2%. Characterizing conditions under which chlorine isotopic fractionation may occur is clearly of interest to planetary science. Thus, we have initiated development of a chlorine isotopic analysis technique using TIMS at NASA-JSC. We present here a progress report on the current status of development at JSC and discuss the possible application of chlorine isotopic analysis to Martian meteorites in a search for fluid- and possibly biological activity on Mars.

40 CFR 268.40 - Applicability of treatment standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... chlorinated aliphatic hydrocarbons by free radical catalyzed processes. These chlorinated aliphatic... chlorinated aliphatic hydrocarbons, by free radical catalyzed processes. These chlorinated aliphatic... production of certain chlorinated aliphatic hydrocarbons, by free radical catalyzed processes. These...

40 CFR 268.40 - Applicability of treatment standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... chlorinated aliphatic hydrocarbons by free radical catalyzed processes. These chlorinated aliphatic... chlorinated aliphatic hydrocarbons, by free radical catalyzed processes. These chlorinated aliphatic... production of certain chlorinated aliphatic hydrocarbons, by free radical catalyzed processes. These...

Indium-chlorine and gallium-chlorine tetrasubstituted phthalocyanines in a bulk system, Langmuir monolayers and Langmuir-Blodgett nanolayers--spectroscopic investigations.

PubMed

Bursa, B; Wróbel, D; Biadasz, A; Kędzierski, K; Lewandowska, K; Graja, A; Szybowicz, M; Durmuş, M

2014-07-15

The paper deals with spectroscopic characterization of metallic phthalocyanines (Pc's) (indium and gallium) complexed with chlorine and substituted with four benzyloxyphenoxy peripheral groups in bulk systems, 2D Langmuir monolayers and Langmuir-Blodgett nanolayers. An influence of the molecular structure of dyes (the presence of metal and of substitutes attached to the phthalocyanine macroring) on the in situ measurements of light absorption is reported. Molecular arrangement of the phthalocyanine molecular skeleton in the Langmuir monolayers on water substrate and in the Langmuir-Blodgett nanolayers is evaluated. A comparison of the light absorption spectra of the phthalocyanine monolayers with the spectra of the dyes in solution supports the existence of dye aggregates in the monolayer. It was shown that the type of dye aggregates (oblique and H types) depends markedly on the dye molecular structures. The NIR-IR, IR reflection-absorption and Raman spectra are also monitored for Langmuir-Blodgett nanolayers in non-polarized and polarized light. It was shown that the dye molecules in the Langmuir-Blodgett layers are oriented nearly vertically with respect to a gold substrate. Copyright © 2014 Elsevier B.V. All rights reserved.

Chlorine hazard evaluation for the zinc-chlorine electric vehicle battery. Final technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zalosh, R.G.; Bajpai, S.N.; Short, T.P.

1980-04-01

An evaluation of the hazards associated with conceivable accidental chlorine releases from zinc-chlorine electric vehicle batteries is presented. Since commercial batteries are not yet available, this hazard assessment is based both on theoretical chlorine dispersion models and small-scale and large-scale spill tests with chlorine hydrate. Six spill tests involving chlorine hydrate indicate that the danger zone in which chlorine vapor concentrations intermittently exceed 100 ppM extends at least 23 m directly downwind of a spill onto a warm road surface. Chlorine concentration data from the hydrate spill tests compare favorably with calculations based on a quasi-steady area source dispersion modelmore » and empirical estimates of the hydrate decomposition rate. The theoretical dispersion model has been combined with assumed hydrate spill probabilities and current motor vehicle accident statistics in order to project expected chlorine-induced fatality rates. These calculations indicate that expected chlorine fatality rates are several times higher in a city with a warm and calm climate than in a colder and windier city. Calculated chlorine-induced fatality rate projections for various climates are presented as a function of hydrate spill probability in order to illustrate the degree of vehicle/battery crashworthiness required to maintain chlorine-induced fatality rates below current vehicle fatility rates due to fires and asphyxiations.« less

Chlorination kinetics of glyphosate and its by-products: modeling approach.

PubMed

Brosillon, Stephan; Wolbert, Dominique; Lemasle, Marguerite; Roche, Pascal; Mehrsheikh, Akbar

2006-06-01

Chlorination reactions of glyphosate, glycine, and sodium cyanate were conducted in well-agitated reactors to generate experimental kinetic measurements for the simulation of chlorination kinetics under the conditions of industrial water purification plants. The contribution of different by-products to the overall degradation of glyphosate during chlorination has been identified. The kinetic rate constants for the chlorination of glyphosate and its main degradation products were either obtained by calculation according to experimental data or taken from published literature. The fit of the kinetic constants with experimental data allowed us to predict consistently the concentration of the majority of the transitory and terminal chlorination products identified in the course of the glyphosate chlorination process. The simulation results conducted at varying aqueous chlorine/glyphosate molar ratios have shown that glyphosate is expected to degrade in fraction of a second under industrial aqueous chlorination conditions. Glyphosate chlorination products are not stable under the conditions of drinking water chlorination and are degraded to small molecules common to the degradation of amino acids and other naturally occurring substances in raw water. The kinetic studies of the chlorination reaction of glyphosate, together with calculations based on kinetic modeling in conditions close to those at real water treatment plants, confirm the reaction mechanism that we have previously suggested for glyphosate chlorination.

40 CFR 401.15 - Toxic pollutants.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (technical mixture and metabolites) 14. Chlorinated benzenes (other than di-chlorobenzenes) 15. Chlorinated... ethers (chloroethyl and mixed ethers) 17. Chlorinated naphthalene 18. Chlorinated phenols (other than those listed elsewhere; includes trichlorophenols and chlorinated cresols) 19. Chloroform 20. 2...

Analysis of residual chlorine in simple drinking water distribution system with intermittent water supply

NASA Astrophysics Data System (ADS)

Goyal, Roopali V.; Patel, H. M.

2015-09-01

Knowledge of residual chlorine concentration at various locations in drinking water distribution system is essential final check to the quality of water supplied to the consumers. This paper presents a methodology to find out the residual chlorine concentration at various locations in simple branch network by integrating the hydraulic and water quality model using first-order chlorine decay equation with booster chlorination nodes for intermittent water supply. The explicit equations are developed to compute the residual chlorine in network with a long distribution pipe line at critical nodes. These equations are applicable to Indian conditions where intermittent water supply is the most common system of water supply. It is observed that in intermittent water supply, the residual chlorine at farthest node is sensitive to water supply hours and travelling time of chlorine. Thus, the travelling time of chlorine can be considered to justify the requirement of booster chlorination for intermittent water supply.

Design and synthesis of chlorinated benzothiadiazole-based polymers for efficient solar energy conversion

DOE PAGES

Hu, Zhiming; Chen, Hui; Qu, Jianfei; ...

2017-03-10

Here, chlorinated benzothiadiazide based polymers with multiple chlorine atoms has been designed and synthesized for polymer solar cells with enhanced open circuit voltage up to 0.85 V. The chlorine substitution is found to significantly adjust the band gap of the polymers, and change polymer’s orientation from random morphology of chlorine free PBT4T-2OD, to mixed face-on packing of one chlorine substituted PCBT4T-2OD, and finally to edge-on of two chlorine substituted PCCBT4T-2OD. The optimized chlorinated polymer, PCBT4T-2OD with only one chlorine atom substituted on BT moiety, has been founded to achieve the highest power conversion efficiency up to 8.20% with PC 71BM,more » which is about 68% higher than that of its non-chlorine analogues.« less

Detection of hexamethonium-perchlorate association complexes using NACE-MS.

PubMed

Groom, Carl A; Hawari, Jalal

2007-02-01

Perchlorate (ClO(4) (+)) and other chlorine oxide anions were observed to complex weakly with hexamethonium (1,6-bis-(trimethylammonium)-hexane) in both aqueous and polar nonaqueous solvents. The resultant positively charged complexes were resolved by NACE using 2-propanol/acetone electrolytes prior to mass spectrometric detection using an Agilent(3D)CE system coupled to a Bruker Esquire 3000+ quadrupole IT mass detector. Using electrokinetic injection, the method detection limit for perchlorate in nonaqueous media was 10 microg/L. The isotope patterns due to the presence of (35)Cl and (37)Cl in complex mass spectra allowed for unambiguous identification of perchlorate, chlorate (ClO(3) (+)), chlorite (ClO(2) (+)), and chloride (Cl(+)) in photoreaction samples.

Conciliatory Inductive Model Explaining the Origin of Changes in the η(2)-SiH Bond Length Caused by Presence of Strongly Electronegative Atoms X (X = F, Cl) in Cp(OC)2Mn[η(2)-H(SiH3-nXn)] (n = 0-3) Complexes.

PubMed

Jabłoński, Mirosław

2016-06-23

Using three theoretical methods, QTAIM, IQA, and NCI, we analyze an influence of halogen atoms X (X = F, Cl) substituted at various positions in the -SiH3-nXn group on the charge density distribution within the η(2)-SiH bond and on the SiH bond energies in Cp(OC)2Mn[η(2)-H(SiH3-nXn)] complexes and isolated HSiH3-nXn molecules. It is shown that shortening of the η(2)-SiH bond in Cp(OC)2Mn[η(2)-H(SiH3-nXn)] complexes should be considered as a normal inductive result of halogenation. This η(2)-SiH bond's compression may, however, be overcome by a predominant elongation resulting from a contingent presence of a halogen atom at position trans to the η(2)-SiH bond. This trans effect is particularly large for bulky and highly polarizable chlorine. Moreover, peculiar properties of the trans chlorine atom are manifested in several ways. To explain the origin of all the observed changes in both the length and the electron charge distribution of the η(2)-SiH bond in investigated Cp(OC)2Mn[η(2)-H(SiH3-nXn)] complexes a new model, called the Conciliatory Inductive Model, is being proposed.

Comparative investigation of X-ray contrast medium degradation by UV/chlorine and UV/H2O2.

PubMed

Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Pang, Suyan

2018-02-01

The degradation of iopamidol and diatrizoate sodium (DTZ) by UV/chlorine was carried out according to efficiency, mechanism, and oxidation products, and compared to that by UV/H 2 O 2 . The pseudo-first order rate (k') of iopamidol and DTZ was accelerated by UV/chlorine compared to that by UV and chlorine alone. k' of iopamidol and DTZ by UV/chlorine increased with increasing chlorine dosage. Both of iopamidol and DTZ could not be effectively removed by UV/H 2 O 2 compared to that by UV/chlorine. Secondary radicals (Cl 2 - and ClO) rather than primary radicals (HO and Cl) were demonstrated to be mainly responsible for the enhanced removal of iopamidol and DTZ by UV/chlorine. The oxidation products of iopamidol and DTZ resulting from UV/chlorine and UV/H 2 O 2 process were identified, and differences existed in the two systems. IO 3 - (the desired sink of I - ) was the major inorganic product in the UV/chlorine process whereas I - was the predominant inorganic product in the UV/H 2 O 2 process. The formation of chlorine-containing products during the degradation of iopamidol and DTZ by UV/chlorine was also observed. H-abstraction, additions, de-iodination were shared during the degradation of iopamidol by UV/chlorine and UV/H 2 O 2 . Neutral pH condition was preferred for the removal of iopamidol and DTZ by UV/chlorine. UV/chlorine could also be applied in real waters for the removal of iopamidol and DTZ. Copyright © 2017 Elsevier Ltd. All rights reserved.

EFFECTS OF OZONE, CHLORINE DIOXIDE, CHLORINE, AND MONOCHLORAMINE ON CRYTOSPORIDIUM PARVUM OOCYST VIABILITY

EPA Science Inventory

Purified Cryptosporiodium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were compareatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlor...

21 CFR 173.300 - Chlorine dioxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Chlorine dioxide. 173.300 Section 173.300 Food and... Additives § 173.300 Chlorine dioxide. Chlorine dioxide (CAS Reg. No. 10049-04-4) may be safely used in food... chlorine dioxide with respect to all chlorine species as determined by Method 4500-ClO2 E in the “Standard...

Microbial chlorination of organic matter in forest soil: investigation using 36Cl-chloride and its methodology.

PubMed

Rohlenová, J; Gryndler, M; Forczek, S T; Fuksová, K; Handova, V; Matucha, M

2009-05-15

Chloride, which comes into the forest ecosystem largely from the sea as aerosol (and has been in the past assumed to be inert), causes chlorination of soil organic matter. Studies of the chlorination showed that the content of organically bound chlorine in temperate forest soils is higher than that of chloride, and various chlorinated compounds are produced. Our study of chlorination of organic matter in the fermentation horizon of forest soil using radioisotope 36Cl and tracer techniques shows that microbial chlorination clearly prevails over abiotic, chlorination of soil organic matter being enzymatically mediated and proportional to chloride content and time. Long-term (>100 days) chlorination leads to more stable chlorinated substances contained in the organic layer of forest soil (overtime; chlorine is bound progressively more firmly in humic acids) and volatile organochlorines are formed. Penetration of chloride into microorganisms can be documented by the freezing/thawing technique. Chloride absorption in microorganisms in soil and in litter residues in the fermentation horizon complicates the analysis of 36Cl-chlorinated soil. The results show that the analytical procedure used should be tested for every soil type under study.

Study of Synthesis of N-Nitroborazine Compounds. I. Nitryl Chloride as Nitrating Agent.

DTIC Science & Technology

dinitrogen tetroxide (N2O4) as the solid complexes of boron trifluoride (BF3). Nearly water-white nitryl chloride was obtained in this manner. A tinge of...yellow was attributed to the presence of chlorine . The reaction of nitryl chloride with a model compound, lithium dimethylamide, was found to yield

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Zhiming; Chen, Hui; Qu, Jianfei

Here, chlorinated benzothiadiazide based polymers with multiple chlorine atoms has been designed and synthesized for polymer solar cells with enhanced open circuit voltage up to 0.85 V. The chlorine substitution is found to significantly adjust the band gap of the polymers, and change polymer’s orientation from random morphology of chlorine free PBT4T-2OD, to mixed face-on packing of one chlorine substituted PCBT4T-2OD, and finally to edge-on of two chlorine substituted PCCBT4T-2OD. The optimized chlorinated polymer, PCBT4T-2OD with only one chlorine atom substituted on BT moiety, has been founded to achieve the highest power conversion efficiency up to 8.20% with PC 71BM,more » which is about 68% higher than that of its non-chlorine analogues.« less

DBP formation from degradation of DEET and ibuprofen by UV/chlorine process and subsequent post-chlorination.

PubMed

Aghdam, Ehsan; Xiang, Yingying; Sun, Jianliang; Shang, Chii; Yang, Xin; Fang, Jingyun

2017-08-01

The formation of disinfection by-products (DBPs) from the degradation of N,N-diethyl-3-methyl benzoyl amide (DEET) and ibuprofen (IBP) by the ultraviolet irradiation (UV)/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H 2 O 2 process. The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H 2 O 2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species (RCS) and hydroxyl radicals (HO) in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50% after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine (TOCl), respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H 2 O 2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%-63% higher, likely due to the generation of more DBP precursors from the attack of RCS, in addition to HO. Copyright © 2017. Published by Elsevier B.V.

Bioenhanced DNAPL Dissolution: Understanding how Microbial Competition, Biostimulation, and Bioaugmentation Affect Source Zone Longevity

NASA Astrophysics Data System (ADS)

Becker, J. G.; Seagren, E. A.

2006-12-01

The presence of dense non-aqueous phase liquids (DNAPLs) at many chlorinated ethene-contaminated sites can greatly extend the time frames needed to reduce dissolved contaminants to regulatory levels using bioremediation. However, it has been demonstrated that mass removal from chlorinated ethene DNAPLs can potentially be enhanced through dehalorespiration of dissolved contaminants near the NAPL-water interface. Although promising, the amount of "bioenhancement" that can be achieved under optimal conditions is currently not known, and the real significance and engineering potential of this phenomenon currently are not well understood, in part because it can be influenced by a complex set of factors, including DNAPL properties, hydrodynamics, substrate concentrations, and microbial competition for growth substrates. In this study it is hypothesized that: (1) different chlorinated ethene-respiring strains may dominate within different zones of a contaminant plume emanating from a DNAPL source zone due to variations in substrate availability, and microbial competition for chlorinated ethenes and/or electron donors; and (2) the outcome of competitive interactions near the DNAPL source zone will affect the longevity of DNAPL source zones by influencing the degree of dissolution bioenhancement, while the outcome of competitive interactions further downgradient will determine the extent of contaminant dechlorination. To demonstrate the validity of the proposed hypothesis, a series of simple, "proof-of-concept," mathematical simulations evaluating the effects of competitive interactions on the distribution of dehalorespirers at the DNAPL-water interface, the dissolution of tetrachloroethene (PCE), and extent of PCE detoxification were performed in a model competition scenario, in which Dehalococcoides ethenogenes and another dehalorespirer (Desulfuromonas michiganensis) compete for the electron acceptor (PCE) and/or electron donor. The model domain for this evaluation simulates a contaminant-source zone consisting of DNAPL ganglia trapped in a subsurface porous medium that slowly releases organic pollutants into the groundwater flowing past it. The model used in the simulations was based on a biokinetic model recently developed by Becker [Environ. Sci. Technol. 40(14):4473-4480] to describe competition among PCE-respiring populations in a homogenous continuously-stirred tank reactor. Becker's model was expanded by adding terms for chlorinated ethene partitioning between the DNAPL and aqueous phases, as well as advection and dispersion of aqueous chlorinated ethenes. The results of these preliminary simulations demonstrate that the outcome of competition between populations for growth substrates can have a significant impact on bioenhancement and, thus, on DNAPL source zone longevity. Although these proof-of- concept simulations do not incorporate all of the complexity of actual field systems, the modeling results are useful for identifying which parameters are important in determining the outcome of competition in the different scenarios and its impact on DNAPL dissolution. This information is needed to understand how biostimulation and bioaugmentation affect bioenhancement by stimulating different populations and develop bioremediation strategies that incorporate these treatment technologies while balancing the twin clean-up goals of reduced source longevity and complete detoxification.

Acute lung injury and persistent small airway disease in a rabbit model of chlorine inhalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musah, Sadiatu; Schlueter, Connie F.; Humphrey, Da

Chlorine is a pulmonary toxicant to which humans can be exposed through accidents or intentional releases. Acute effects of chlorine inhalation in humans and animal models have been well characterized, but less is known about persistent effects of acute, high-level chlorine exposures. In particular, animal models that reproduce the long-term effects suggested to occur in humans are lacking. Here, we report the development of a rabbit model in which both acute and persistent effects of chlorine inhalation can be assessed. Male New Zealand White rabbits were exposed to chlorine while the lungs were mechanically ventilated. After chlorine exposure, the rabbitsmore » were extubated and were allowed to survive for up to 24 h after exposure to 800 ppm chlorine for 4 min to study acute effects or up to 7 days after exposure to 400 ppm for 8 min to study longer term effects. Acute effects observed 6 or 24 h after inhalation of 800 ppm chlorine for 4 min included hypoxemia, pulmonary edema, airway epithelial injury, inflammation, altered baseline lung mechanics, and airway hyperreactivity to inhaled methacholine. Seven days after recovery from inhalation of 400 ppm chlorine for 8 min, rabbits exhibited mild hypoxemia, increased area of pressure–volume loops, and airway hyperreactivity. Lung histology 7 days after chlorine exposure revealed abnormalities in the small airways, including inflammation and sporadic bronchiolitis obliterans lesions. Immunostaining showed a paucity of club and ciliated cells in the epithelium at these sites. These results suggest that small airway disease may be an important component of persistent respiratory abnormalities that occur following acute chlorine exposure. This non-rodent chlorine exposure model should prove useful for studying persistent effects of acute chlorine exposure and for assessing efficacy of countermeasures for chlorine-induced lung injury. - Highlights: • A novel rabbit model of chlorine-induced lung disease was developed. • Acute effects of chlorine were pulmonary edema, hypoxemia and impaired lung function. • Persistent small airway disease developed following recovery from acute injury. • Small airway disease included inflammation and bronchiolitis obliterans lesions. • The model should be useful for studying chlorine lung injury and testing treatments.« less

A new method for calculation of the chlorine demand of natural and treated waters.

PubMed

Warton, Ben; Heitz, Anna; Joll, Cynthia; Kagi, Robert

2006-08-01

Conventional methods of calculating chlorine demand are dose dependent, making intercomparison of samples difficult, especially in cases where the samples contain substantially different concentrations of dissolved organic carbon (DOC), or other chlorine-consuming species. Using the method presented here, the values obtained for chlorine demand are normalised, allowing valid comparison of chlorine demand between samples, independent of the chlorine dose. Since the method is not dose dependent, samples with substantially differing water quality characteristics can be reliably compared. In our method, we dosed separate aliquots of a water sample with different chlorine concentrations, and periodically measured the residual chlorine concentrations in these subsamples. The chlorine decay data obtained in this way were then fitted to first-order exponential decay functions, corresponding to short-term demand (0-4h) and long-term demand (4-168 h). From the derived decay functions, the residual concentrations at a given time within the experimental time window were calculated and plotted against the corresponding initial chlorine concentrations, giving a linear relationship. From this linear function, it was then possible to determine the residual chlorine concentration for any initial concentration (i.e. dose). Thus, using this method, the initial chlorine dose required to give any residual chlorine concentration can be calculated for any time within the experimental time window, from a single set of experimental data.

40 CFR 704.43 - Chlorinated naphthalenes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chlorinated naphthalenes. 704.43... § 704.43 Chlorinated naphthalenes. (a) Definitions. (1) Extent of chlorination means the percent by... means the relative amounts of each isomeric chlorinated naphthalene that composes the chemical substance...

40 CFR 704.43 - Chlorinated naphthalenes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chlorinated naphthalenes. 704.43... § 704.43 Chlorinated naphthalenes. (a) Definitions. (1) Extent of chlorination means the percent by... means the relative amounts of each isomeric chlorinated naphthalene that composes the chemical substance...

Characterization and Application of a Chlorine Microelectrode for Measuring Monochloramine within a Biofilm

EPA Science Inventory

Chlorine microelectrodes with tip sizes of 5-15 μm were developed and used to measure biofilm monochloramine penetration profiles. The chlorine microelectrode showed response to total chlorine, including free chlorine, monochloramine, and dichloramine under various conditions. ...

Acute Lung Injury and Persistent Small Airway Disease in a Rabbit Model of Chlorine Inhalation

PubMed Central

Musah, Sadiatu; Schlueter, Connie F.; Humphrey, David M.; Powell, Karen S.; Roberts, Andrew M.; Hoyle, Gary W.

2016-01-01

Chlorine is a pulmonary toxicant to which humans can be exposed through accidents or intentional releases. Acute effects of chlorine inhalation in humans and animal models have been well characterized, but less is known about persistent effects of acute, high-level chlorine exposures. In particular, animal models that reproduce the long-term effects suggested to occur in humans are lacking. Here, we report the development of a rabbit model in which both acute and persistent effects of chlorine inhalation can be assessed. Male New Zealand White rabbits were exposed to chlorine while the lungs were mechanically ventilated. After chlorine exposure, the rabbits were extubated and were allowed to survive for up to 24 h after exposure to 800 ppm chlorine for 4 min to study acute effects or up to 7 days after exposure to 400 ppm for 8 min to study longer term effects. Acute effects observed 6 or 24 h after inhalation of 800 ppm chlorine for 4 min included hypoxemia, pulmonary edema, airway epithelial injury, inflammation, altered baseline lung mechanics, and airway hyperreactivity to inhaled methacholine. Seven days after recovery from inhalation of 400 ppm chlorine for 8 min, rabbits exhibited mild hypoxemia, increased area of pressure-volume loops, and airway hyperreactivity. Lung histology 7 days after chlorine exposure revealed abnormalities in the small airways, including inflammation and sporadic bronchiolitis obliterans lesions. Immunostaining showed a paucity of club and ciliated cells in the epithelium at these sites. These results suggest that small airway disease may be an important component of persistent respiratory abnormalities that occur following acute chlorine exposure. This non-rodent chlorine exposure model should prove useful for studying persistent effects of acute chlorine exposure and for assessing efficacy of countermeasures for chlorine-induced lung injury. PMID:27913141

Progress towards synthetic chlorins with graded polarity, conjugatable substituents, and wavelength tunability

DOE PAGES

Ra, Doyoung; Gauger, Kelly A.; Muthukumaran, Kannan; ...

2015-04-01

Advances in chlorin synthetic chemistry now enable the de novo preparation of diverse chlorin-containing molecular architectures. Five distinct molecular designs have been explored here, including hydrophobic bioconjugatable (oxo)chlorins; a hydrophilic bioconjugatable chlorin; a trans-ethynyl/iodochlorin building block; a set of chlorins bearing electron-rich (methoxy, dimethylamino, methylthio) groups at the 3-position; and a set of ten 3,13-disubstituted chlorins chiefly bearing groups with extended π-moieties. Altogether 23 new chlorins (17 targets, 6 intermediates) have been prepared. Lastly, the challenge associated with molecular designs that encompass the combination of “hydrophilic, bioconjugatable and wavelength-tunable” chiefly resides in the nature of the hydrophilic unit.

Higher modulus compositions incorporating particulate rubber

DOEpatents

Bauman, B.D.; Williams, M.A.; Bagheri, R.

1997-12-02

Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles. 2 figs.

Higher modulus compositions incorporating particulate rubber

DOEpatents

McInnis, E.L.; Scharff, R.P.; Bauman, B.D.; Williams, M.A.

1995-01-17

Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles. 2 figures.

Higher modulus compositions incorporating particulate rubber

DOEpatents

McInnis, E.L.; Bauman, B.D.; Williams, M.A.

1996-04-09

Rubber particles, to be used as fillers or extenders for various composite polymer systems, are chlorinated by a gas-solid phase reaction with a chlorine-containing gas. A composite polymer containing the chlorinated rubber fillers or extenders exhibits a higher flexural modulus than if prepared using an unchlorinated rubber filler or extender. Chlorination of the rubber particles is carried out by contacting the finely divided rubber particles with a chlorine-containing gas comprising at least about 5 volume percent chlorine. Advantageously, the chlorine can be diluted with air, nitrogen or other essentially inert gases and may contain minor amounts of fluorine. Improved performance is obtained with nitrogen dilution of the chlorine gas over air dilution. Improved polymer composite systems having higher flexural modulus result from the use of the chlorinated rubber particles as fillers instead of unchlorinated rubber particles. 2 figs.

Evaluation of Organic Proxies for Quantifying Past Primary Productivity

NASA Astrophysics Data System (ADS)

Raja, M.; Rosell-Melé, A.; Galbraith, E.

2017-12-01

Ocean primary productivity is a key element of the marine carbon cycle. However, its quantitative reconstruction in the past relies on the use of biogeochemical models as the available proxy approaches are qualitative at best. Here, we present an approach that evaluates the use of phytoplanktonic biomarkers (i.e. chlorins and alkenones) as quantitative proxies to reconstruct past changes in marine productivity. We compare biomarkers contents in a global suite of core-top sediments to sea-surface chlorophyll-a abundance estimated by satellites over the last 20 years, and the results are compared to total organic carbon (TOC). We also assess satellite data and detect satellite limitations and biases due to the complexity of optical properties and the actual defined algorithms. Our findings show that sedimentary chlorins can be used to track total sea-surface chlorophyll-a abundance as an indicator for past primary productivity. However, degradation processes restrict the application of this proxy to concentrations below a threshold value (1µg/g). Below this threshold, chlorins are a useful tool to identify reducing conditions when used as part of a multiproxy approach to assess redox sedimentary conditions (e.g. using Re, U). This is based on the link between anoxic/disoxic conditions and the flux of organic matter from the sea-surface to the sediments. We also show that TOC is less accurate than chlorins for estimating sea-surface chlorophyll-a due to the contribution of terrigenous organic matter, and the different degradation pathways of all organic compounds that TOC includes. Alkenones concentration also relates to primary productivity, but they are constrained by different processes in different regions. In conclusion, as lons as specific constraints are taken into account, our study evaluates the use of chlorins and alkenones as quantitative proxies of past primary productivity, with more accuracy than by using TOC.

Chlorine isotope fractionation between chloride (Cl-) and dichlorine (Cl2)

NASA Astrophysics Data System (ADS)

Giunta, Thomas; Labidi, Jabrane; Eggenkamp, Hans G. M.

2017-09-01

The use of chlorine stable isotopes (35Cl and 37Cl) can help to constrain natural processes that involve chlorine species with different oxidation states. Theoretical studies based on thermodynamic and quantum mechanical approaches predict large isotope fractionation during redox reactions but to date, these reactions have not been studied experimentally. Here, we explore the chlorine isotope fractionation during the oxidation of hydrated Cl- (redox state of -I) to Cl2 (redox state of 0) at 25 °C and at 0 °C. Our apparatus consists of a sealed glass reactor where liquid HCl is mixed with liquid H2O2, a strong oxidant. Following complex reaction pathways, this mixture ultimately leads to the oxidation of Cl- and to the formation of Cl2 gas. As long as it is degassing, the Cl2 gas is flushed out of solution using N2 as a vector-gas from the glass-reactor to a potassium hydroxide (KOH) solution (pH 14) where it disproportionates into soluble species: Cl- and ClO-. After each experiment, the chlorine isotopic composition was measured in the recovered KOH-trap solution, as well as in the residual HCl solution. Consistent with theoretical predictions, the produced Cl2 gas is always enriched in the heavier 37Cl as compared to the initial Cl-reservoir. The following isotope fractionation factors are obtained: At 0 °C the isotopic fractionation 1000ln α(Cl2-Cl-) is 4.51 (+1.65/-0.49)‰ At 25 °C the isotopic fractionation 1000ln α(Cl2-Cl-) is 3.94 (+0.69/-0.18)‰. From the obtained data it is suggested that the production of Cl2 gas in our experiments is best described by a closed-system distillation. Our results are in agreement with published theoretical ab-initio calculations.

Short- and medium-chain chlorinated paraffins in air and soil of subtropical terrestrial environment in the pearl river delta, South China: distribution, composition, atmospheric deposition fluxes, and environmental fate.

PubMed

Wang, Yan; Li, Jun; Cheng, Zhineng; Li, Qilu; Pan, Xiaohui; Zhang, Ruijie; Liu, Di; Luo, Chunling; Liu, Xiang; Katsoyiannis, Athanasios; Zhang, Gan

2013-03-19

Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 μg/sampler (17.69 ng/m(3)) and 4.1 μg/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 μg/(m(2)d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C(10-11) C(l6-7) and C(14) C(l6-7), C(10-12) C(l6-7) and C(14) C(l6-8), and C(11-12) C(l6-8) and C(14) C(l7-8) dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.

Upper-atmosphere Aerosols: Properties and Natural Cycles

NASA Technical Reports Server (NTRS)

Turco, Richard P.

1992-01-01

The middle atmosphere is rich in its variety of particulate matter, which ranges from meteorite debris, to sulfate aerosols, to polar stratospheric ice clouds. Volcanic eruptions strongly perturb the stratospheric sulfate (Junge) layer. High-altitude 'noctilucent' ice clouds condense at the summer mesopause. The properties of these particles, including their composition, sizes, and geographical distribution, are discussed, and their global effects, including chemical, radiative, and climatic roles, are reviewed. Polar stratospheric clouds (PSCs) are composed of water and nitric acid in the form of micron-sized ice crystals. These particles catalyze reactions of chlorine compounds that 'activate' otherwise inert chlorine reservoirs, leading to severe ozone depletions in the southern polar stratosphere during austral spring. PSCs also modify the composition of the polar stratosphere through complex physiocochemical processes, including dehydration and denitrification, and the conversion of reactive nitrogen oxides into nitric acid. If water vapor and nitric acid concentrations are enhanced by high-altitude aircraft activity, the frequency, geographical range, and duration of PSCs might increase accordingly, thus enhancing the destruction of the ozone layer (which would be naturally limited in geographical extent by the same factors that confine the ozone hole to high latitudes in winter). The stratospheric sulfate aerosol layer reflects solar radiation and increases the planetary albedo, thereby cooling the surface and possibly altering the climate. Major volcanic eruptions, which increase the sulfate aerosol burden by a factor of 100 or more, may cause significant global climate anomalies. Sulfate aerosols might also be capable of activating stratospheric chlorine reservoirs on a global scale (unlike PCSs, which represent a localized polar winter phenomenon), although existing evidence suggests relatively minor perturbations in chlorine chemistry. Nevertheless, if atmospheric concentrations of chlorine (associated with anthropogenic use of chlorofluorocarbons) continue to increase by a factor of two or more in future decades, aircraft emissions of sulfur dioxide and water vapor may take on greater significance.

Evaluating the fate of chlorinated ethenes in streambed sediments by combining stable isotope, geochemical and microbial methods

NASA Astrophysics Data System (ADS)

Abe, Yumiko; Aravena, Ramon; Zopfi, Jakob; Parker, Beth; Hunkeler, Daniel

2009-06-01

The occurrence of chlorinated ethene transformation in a streambed was investigated using concentration and carbon isotope data from water samples taken at different locations and depths within a 15 × 25 m study area across which a tetrachloroethene (PCE) plume discharges. Furthermore, it was evaluated how the degree of transformation is related to groundwater discharge rates, redox conditions, solid organic matter content (SOM) and microbial factors. Groundwater discharge rates were quantified based on streambed temperatures, and redox conditions using concentrations of dissolved redox-sensitive species. The degree of chlorinated ethene transformation was highly variable in space from no transformation to transformation beyond ethene. Complete reductive dechlorination to ethane and ethene occurred at locations with at least sulfate-reducing conditions and with a residence time in the samples streambed zone (80 cm depth) of at least 10 days. Among these locations, Dehalococcoides was detected using a PCR method where SOM contents were > 2% w/w and where transformation proceeded beyond ethene. However, it was not detected at locations with low SOM, which may cause an insufficient H 2 supply to sustain a detectably dense Dehalococcoides population. Additionally, it is possible that other organisms are responsible for the biodegradation. A microcosm study with streambed sediments demonstrated the potential of VC oxidation throughout the site even at locations without a pre-exposure to VC, consistent with the detection of the epoxyalkane:coenzyme M transferase (EaCoMT) gene involved in the degradation of chlorinated ethenes via epoxidation. In contrast, no aerobic transformation of cDCE in microcosms over a period of 1.5 years was observed. In summary, the study demonstrated that carbon isotope analysis is a sensitive tool to identify the degree of chlorinated ethene transformation even in hydrologically and geochemically complex streambed systems. In addition, it was observed that the degree of transformation is related to redox conditions, which in turn depend on groundwater discharge rates.

21 CFR 177.2430 - Polyether resins, chlorinated.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyether resins, chlorinated. 177.2430 Section 177... Components of Articles Intended for Repeated Use § 177.2430 Polyether resins, chlorinated. Chlorinated..., in accordance with the following prescribed conditions: (a) The chlorinated polyether resins are...

78 FR 72640 - Countervailing Duty Investigation of Chlorinated Isocyanurates From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... Investigation of Chlorinated Isocyanurates From the People's Republic of China: Postponement of Preliminary... duty investigation of chlorinated isocyanurates (``chlorinated isos'') from the People's Republic of...\\ \\1\\ See Chlorinated Isocyanurates from the People's Republic of China: Initiation of Countervailing...

IDENTIFICATION OF NEW DRINKING WATER DISINFECTION BY-PRODUCTS FROM OZONE, CHLORINE DIOXIDE, CHLORAMINE, AND CHLORINE

EPA Science Inventory

Due to concern over the potential adverse health effects of trihalomethanes (THMs) and other chlorinated by-products in chlorinated drinking water, alternative disinfection methods are being explored. Ozone, chlorine dioxide, and chloramine are currently popular alternatives to ...

Temperature sensitivity indicates that chlorination of organic matter in forest soil is primarily biotic.

PubMed

Bastviken, David; Svensson, Teresia; Karlsson, Susanne; Sandén, Per; Oberg, Gunilla

2009-05-15

Old assumptions that chloride is inert and that most chlorinated organic matter in soils is anthropogenic have been challenged by findings of naturally formed organochlorines. Such natural chlorination has been recognized for several decades, but there are still very few measurements of chlorination rates or estimates of the quantitative importance of terrestrial chlorine transformations. While much is known about the formation of specific compounds, bulk chlorination remains poorly understood in terms of mechanisms and effects of environmental factors. We quantified bulk chlorination rates in coniferous forest soil using 36Cl-chloride in tracer experiments at different temperatures and with and without molecular oxygen (O2). Chlorination was enhanced by the presence of O2 and had a temperature optimum at 20 degrees C. Minimum rates were found at high temperatures (50 degrees C) or under anoxic conditions. The results indicate (1) that most of the chlorination between 4 and 40 degrees C was biotic and driven by O2 dependent enzymes, and (2) that there is also slower background chlorination occurring under anoxic conditions at 20 degrees C and under oxic conditions at 50 degrees C. Hence, while oxic and biotic chlorination clearly dominated, chlorination by other processes including possible abiotic reactions was also detected.

Influence of Chlorine Emissions on Ozone Levels in the Troposphere

EPA Science Inventory

Chlorine emissions from cooling towers are emitted mainly as hypochlous acid, not as molecular chlorine. Chlorine emissions from cooling towers in electric utilities in the U.S. are estimated to be 4,400 tons per year. Molecular chlorine increases more tropospheric ozone than hyp...

77 FR 19644 - Chlorinated Isocyanurates From the People's Republic of China: Rescission of Antidumping Duty New...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-02

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... duty order on chlorinated isocyanurates (chlorinated isos) from the People's Republic of China (PRC...; telephone: (202) 482-4261. SUPPLEMENTARY INFORMATION Background The antidumping duty order on chlorinated...

Natural Organohalogens: A New Frontier for Medicinal Agents?

NASA Astrophysics Data System (ADS)

Gribble, Gordon W.

2004-10-01

More than 4000 naturally occurring organohalogen compounds are known. These include a relatively small number of abiogenic organohalogens from volcanoes, forest fires, geothermal processes, and meteorites, and a very large number of biogenic organohalogens produced by myriad living organisms as part of their chemical makeup that serve as hormones, pheromones, repellents, and natural pesticides. From the chemically simple methyl chloride, methyl bromide, and chloroform to the structurally complex vancomycin, pyrroindomycin, and bastadins, the diversity of these organohalogens is unsurpassed among natural products. Most natural organohalogens contain chlorine (2300) or bromine (2100), but a significant number contain iodine (120) or fluorine (30). Several hundred marine natural products contain both chlorine and bromine. The present article focuses on newly discovered biogenic organohalogens, with an emphasis on those biologically active examples from marine organisms, bacteria, terrestrial plants, and higher life forms including humans.

Anticancer activity of the new photosensitizers: dose and cell type dependence

NASA Astrophysics Data System (ADS)

Gyulkhandanyan, Grigor V.; Ghambaryan, Sona S.; Amelyan, Gayane V.; Ghazaryan, Robert K.; Haroutiunian, Samvel G.; Gyulkhandanyan, Aram G.; Gasparyan, Gennadi H.

2005-04-01

The necessity of researches of antitumor efficiency of new photosensitizers (PS) is explained by the opportunity of their application in photodynamic therapy of tumors. PS, selectively accumulated in cancer cells and activated by the light, generate the active oxygen species that cause apoptosis. Earlier, it was shown that PS chlorin e6 (0.3-0.5 μg/ml) induces rat embryo fibroblast-like cell apoptosis. In present work antitumor activity of the new photosensitizers, water-soluble cationic porphyrins and their metal complexes, is investigated. The dose-dependent destruction of cancer cells was shown on PC-12 (pheochromocytoma, rat adrenal gland) and Jurkat (human lymphoma) cell lines. Meso-tetra-[4-N-(2 `- oxyethyl) pyridyl] porphyrin (TOEPyP) and chlorin e6 possessed the same toxicity at LD50 dose on PC-12 cell line, whereas phototoxicity of TOEPyP was 3 times less compared to chlorin e6(LD50=0.2 and 0.075 μg/ml accordingly). The results have shown weak photosensitizing effect of Zn-and Ag-derivatives of TOEPyP on PC-12 cell line. TOEPyP and Zn-TOEPyP (0.1 - 50 μg/ml) were non-toxic for Jurkat cell line, whereas Ag-TOEPyP was toxic at 10 μg/ml (LD90). TOEPyP and chlorin e6 have shown phototoxic effect in the same dose range (LD50=0.5 and 0.3 μg/ml accordingly). The investigation of toxic and phototoxic effects of the new porphyrins revealed significantly different sensitivity of various cell lines to PSs.

Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products.

PubMed

Hrudey, Steve E; Backer, Lorraine C; Humpage, Andrew R; Krasner, Stuart W; Michaud, Dominique S; Moore, Lee E; Singer, Philip C; Stanford, Benjamin D

2015-01-01

Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches.

Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products

PubMed Central

Hrudey, Steve E.; Backer, Lorraine C.; Humpage, Andrew R.; Krasner, Stuart W.; Michaud, Dominique S.; Moore, Lee E.; Singer, Philip C.; Stanford, Benjamin D.

2015-01-01

Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches. PMID:26309063

Mechanochemistry of the LiBH 4–AlCl 3 System: Structural Characterization of the Products by Solid-State NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, T.; Dolotko, O.; Gupta, S.

The double-cation metal borohydride, Li 4Al 3(BH 4) 13, mechanochemically produced from a 13:3 mixture of lithium borohydride (LiBH 4) and aluminum chloride (AlCl 3), has a low hydrogen desorption temperature; however, the material’s decomposition is accompanied by a large emission of toxic diborane (B 2H 6). In this study, we found that a decrease of the LiBH 4:AlCl 3 ratio in the starting mixture yields increased amounts of partially chlorinated products that also dehydrogenate at low temperature, but release negligibly small amounts of diborane. Extensive characterization by solid-state NMR spectroscopy (SSNMR) and powder X-ray diffraction (XRD) found that themore » 11:3 ratio product maintains the Li 4Al 3(BH 4) 13-like structure, with additional Cl – anions substituting for [BH 4] – compared to the 13:3 mixture. Further decrease of relative LiBH 4 concentration in the starting mixture to 9:3 results in a different product composed of tetrahedral [Al(BH 4) 4] - and [Al(BH 4) 2Cl 2] - complexes, in which two hydrogen atoms of each borohydride group are bridged to aluminum sites. Additionally, SSNMR revealed the covalent character of the Al–H bonds, which is not observed in Li 4Al 3(BH 4) 13. In conclusion, these findings suggest that the Al–Cl bonding present in the chlorinated complexes prevents the formation of Al(BH 4) 3, which is a known intermediate leading to the formation of diborane during thermal dehydrogenation of the nearly chlorine-free Li 4Al 3(BH 4) 13.« less

Mechanochemistry of the LiBH 4–AlCl 3 System: Structural Characterization of the Products by Solid-State NMR

DOE PAGES

Kobayashi, T.; Dolotko, O.; Gupta, S.; ...

2017-12-19

The double-cation metal borohydride, Li 4Al 3(BH 4) 13, mechanochemically produced from a 13:3 mixture of lithium borohydride (LiBH 4) and aluminum chloride (AlCl 3), has a low hydrogen desorption temperature; however, the material’s decomposition is accompanied by a large emission of toxic diborane (B 2H 6). In this study, we found that a decrease of the LiBH 4:AlCl 3 ratio in the starting mixture yields increased amounts of partially chlorinated products that also dehydrogenate at low temperature, but release negligibly small amounts of diborane. Extensive characterization by solid-state NMR spectroscopy (SSNMR) and powder X-ray diffraction (XRD) found that themore » 11:3 ratio product maintains the Li 4Al 3(BH 4) 13-like structure, with additional Cl – anions substituting for [BH 4] – compared to the 13:3 mixture. Further decrease of relative LiBH 4 concentration in the starting mixture to 9:3 results in a different product composed of tetrahedral [Al(BH 4) 4] - and [Al(BH 4) 2Cl 2] - complexes, in which two hydrogen atoms of each borohydride group are bridged to aluminum sites. Additionally, SSNMR revealed the covalent character of the Al–H bonds, which is not observed in Li 4Al 3(BH 4) 13. In conclusion, these findings suggest that the Al–Cl bonding present in the chlorinated complexes prevents the formation of Al(BH 4) 3, which is a known intermediate leading to the formation of diborane during thermal dehydrogenation of the nearly chlorine-free Li 4Al 3(BH 4) 13.« less

Evaluation of the fate and transport of chlorinated ethenes in a complex groundwater system discharging to a stream in Wonju, Korea

NASA Astrophysics Data System (ADS)

Lee, Seong-Sun; Kaown, Dugin; Lee, Kang-Kun

2015-11-01

Chlorinated ethenes such as trichloroethylene (TCE) are common and persistent groundwater contaminants. If contaminated groundwater discharges to a stream, then stream water pollution near the contamination site also becomes a problem. In this respect, the fate and transport of chlorinated ethenes around a stream in an industrial complex were evaluated using the concentration of each component, and hydrogeochemical, microbial, and compound-specific carbon isotope data. Temporal and spatial monitoring reveal that a TCE plume originating from main and local source zones continues to be discharged to a stream. Groundwater geochemical data indicate that aerobic conditions prevail in the upgradient area of the studied aquifer, whereas conditions become anaerobic in the downgradient. The TCE molar fraction is high at the main and local source zones, ranging from 87.4 to 99.2% of the total volatile organic compounds (VOCs). An increasing trend in the molar fraction of cis-1, 2-Dichloroethene (cis-DCE) and vinyl chloride (VC) was observed in the downgradient zone of the study area. The enriched δ13C values of TCE and depleted values of cis-DCE in the stream zone, compared to those of the source zone, also suggest biodegradation of VOCs. Microbial community structures in monitoring wells adjacent to the stream zone in the downgradient area were analyzed using 16S rRNA gene-based pyrosequencing to identify the microorganisms responsible for biodegradation. This was attributed to the high relative abundance of dechlorinating bacteria in monitoring wells under anaerobic conditions farthest from the stream in the downgradient area. The multilateral approaches adopted in this study, combining hydrogeochemical and biomolecular methods with compound-specific analyses, indicate that contaminants around the stream were naturally attenuated by active anaerobic biotransformation processes.

Evaluating the environmental fate of short-chain chlorinated paraffins (SCCPs) in the Nordic environment using a dynamic multimedia model.

PubMed

Krogseth, Ingjerd S; Breivik, Knut; Arnot, Jon A; Wania, Frank; Borgen, Anders R; Schlabach, Martin

2013-12-01

Short chain chlorinated paraffins (SCCPs) raise concerns due to their potential for persistence, bioaccumulation, long-range transport and adverse effects. An understanding of their environmental fate remains limited, partly due to the complexity of the mixture. The purpose of this study was to evaluate whether a mechanistic, integrated, dynamic environmental fate and bioaccumulation multimedia model (CoZMoMAN) can reconcile what is known about environmental emissions and human exposure of SCCPs in the Nordic environment. Realistic SCCP emission scenarios, resolved by formula group, were estimated and used to predict the composition and concentrations of SCCPs in the environment and the human food chain. Emissions at the upper end of the estimated range resulted in predicted total concentrations that were often within a factor of 6 of observations. Similar model performance for a complex group of organic contaminants as for the well-known polychlorinated biphenyls strengthens the confidence in the CoZMoMAN model and implies a relatively good mechanistic understanding of the environmental fate of SCCPs. However, the degree of chlorination predicted for SCCPs in sediments, fish, and humans was higher than observed and poorly established environmental half-lives and biotransformation rate constants contributed to the uncertainties in the predicted composition and ∑SCCP concentrations. Improving prediction of the SCCP composition will also require better constrained estimates of the composition of SCCP emissions. There is, however, also large uncertainty and lack of coherence in the existing observations, and better model-measurement agreement will require improved analytical methods and more strategic sampling. More measurements of SCCP levels and compositions in samples from background regions are particularly important.

Chlorination of Wastewater, Manual of Practice No. 4.

ERIC Educational Resources Information Center

Water Pollution Control Federation, Washington, DC.

This manual reviews chlorination practices in the treatment and disposal of wastes from the earliest known applications. The application of chlorination for various purposes is described but no attempt has been made to compare chlorination with other methods. Included are chapters on the development and practice of wastewater chlorination,…

Free Chlorine and Cyanuric Acid Simulator Application ...

EPA Pesticide Factsheets

A web-based application designed to simulate the free chlorine in systems adding free chlorine and cyanuric acid, including the application of Dichlor and Trichlor. A web-based application designed to simulate the free chlorine in systems adding free chlorine and cyanuric acid, including the application of Dichlor and Trichlor.

78 FR 72633 - Chlorinated Isocyanurates From Spain: Final Results of Antidumping Duty Administrative Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... DEPARTMENT OF COMMERCE International Trade Administration [A-469-814] Chlorinated Isocyanurates... administrative review of the antidumping duty order on chlorinated isocyanurates (chlorinated isos) from Spain.\\1... below in the ``Final Results of Review'' section of this notice. \\1\\ See Chlorinated Isocyanurates from...

77 FR 4992 - Chlorinated Isocyanurates From the People's Republic of China: Extension of Time Limit for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... duty order on chlorinated isocyanurates (chlorinated isos) from the People's Republic of China (PRC... requires additional time to complete the preliminary results of the administrative review of chlorinated...

Chlorination. Training Module 2.300.2.77.

ERIC Educational Resources Information Center

Kirkwood Community Coll., Cedar Rapids, IA.

This document is an instructional module package prepared in objective form for use by an instructor familiar with chlorine, the reasons for chlorination and safe operation and maintenance of gas chlorine, dry calcium hypochlorite and liquid sodium hypochlorite chlorination systems for water supply and wastewater treatment facilities. Included are…

Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korich, D.G.; Mead, J.R.; Madore, M.S.

1990-05-01

Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 timesmore » more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.« less

Chlorine isn't Just for Swimming Pools Anymore... Chlorination of Organic Compounds in the Arctic

NASA Astrophysics Data System (ADS)

Han, A.; Raab, T. K.

2013-12-01

The cycling of chlorine between its organic and inorganic forms is known to occur in forest soils, but little is known about the generality of this mechanism, which soil components chlorine attaches to, and at what rate chlorination occurs. The study uses peat-rich tundra soils from Barrow, Alaska varying in age since formation of 50 yrs - 5500 yrs BP, and seeks to measure the rate at which organic molecules are chlorinated and to understand what changes those molecules undergo once chlorinated. Soil abundance of chlorine and bromine was estimated in soils of varying age using X-ray fluorescence, and org-Cl levels were measured using pyro-hydrolysis [Table 1]. We considered activity of the enzyme Chloroperoxidase, and data was gathered using absorbance scans of the organic molecule monochlorodimedone to determine whether it had been chlorinated and if so, at what rate. Additional information was gathered from the chlorination of small organic components of the macromolecule lignin, whose constituent molecules make up a large portion of humic materials critical to soil health, through emission scans and fluorescence scans. The results showed that the enzyme chloroperoxidase, which is found in nature and is associated with fungi or bacteria, attaches a chlorine atom to monochlorodimedone and that similar enzymes found in Arctic soils act on it, as well as the lignin model subunits cinnamaldehyde ((2E)-3-phenylprop-2-enal) and naringenin-7-rhamnoglucoside. The results may provide more information on chlorination rates in the Arctic and may contribute to an understanding of how and at what rate chlorine changes form in nature, and answer questions about ozone deterioration or anthropogenic chlorine impact(s) on the environment.Average Halogen Abundance in Arctic Soils xrf=Energy Dispersive X-Ray Fluorescencepyro= TOX Pyro-Hydrolysis

Inactivation, reactivation and regrowth of indigenous bacteria in reclaimed water after chlorine disinfection of a municipal wastewater treatment plant.

PubMed

Li, Dan; Zeng, Siyu; Gu, April Z; He, Miao; Shi, Hanchang

2013-07-01

Disinfection of reclaimed water prior to reuse is important to prevent the transmission of pathogens. Chlorine is a widely utilized disinfectant and as such is a leading contender for disinfection of reclaimed water. To understand the risks of chlorination resulting from the potential selection of pathogenic bacteria, the inactivation, reactivation and regrowth rates of indigenous bacteria were investigated in reclaimed water after chlorine disinfection. Inactivation of total coliforms, Enterococcus and Salmonella showed linear correlations, with constants of 0.1384, 0.1624 and 0.057 L/(mg.min) and R2 of 0.7617, 0.8316 and 0.845, respectively. However, inactivation of total viable cells by measurement of metabolic activity typically showed a linear correlation at lower chlorine dose (0-22 (mg-min)/L), and a trailing region with chlorine dose increasing from 22 to 69 (mg.min)/L. Reactivation and regrowth of bacteria were most likely to occur after exposure to lower chlorine doses, and extents of reactivation decreased gradually with increasing chlorine dose. In contrast to total coliforms and Enterococcus, Salmonella had a high level of regrowth and reactivation, and still had 2% regrowth even after chlorination of 69 (mg.min)/L and 24 hr storage. The bacterial compositions were also significantly altered by chlorination and storage of reclaimed water, and the ratio of Salmonella was significantly increased from 0.001% to 0.045% after chlorination of 69 (mg.min)/L and 24 hr storage. These trends indicated that chlorination contributes to the selection of chlorine-resistant pathogenic bacteria, and regrowth of pathogenic bacteria after chlorination in reclaimed water with a long retention time could threaten public health security during wastewater reuse.

Guidelines for the Selection of Chemical Protective Clothing. Volume 2. Technical and Reference Manual.

DTIC Science & Technology

1987-02-01

Handler’s Suit for Protection from Chlorine Trifluoride and Elemental Fluorine Technical Report AFRPL-TR-71-44 (August 1971) NTIS AD731556 199 Masterman’s...Protective Clothing for Chlorine , Edition 1 Chlorine Institute Pamphlet 65, The Chlorine Institute, Inc. New York, New York, (June 1978) 15 Anon...Chemical Company Selection of Gloves for Use With Chlorinated Solvents Chlorinated Solvents Information Midland, Michigan 48640 101 Duffy, R.M., A.R.Beer

PPCP degradation by chlorine-UV processes in ammoniacal water: new reaction insights, kinetic modeling and DBP formation.

PubMed

Zhang, Ruochun; Meng, Tan; Huang, Ching-Hua; Ben, Weiwei; Yao, Hong; Liu, Ruini; Sun, Peizhe

2018-06-15

The combination of chlorine and UV (i.e. chlorine-UV process) has been attracting more attentions in recent years due to its ready incorporation into existing water treatment facilities to remove PPCPs. However, limited information is available on the impact of total ammonia nitrogen (TAN). This study investigated two model PPCPs, N,N-diethyl-3-toluamide (DEET) and caffeine (CAF), in the two stages of chlorine-UV process (i.e. chlorination and UV/chlor(am)ine) to elucidate the impact of TAN. During chlorination, the degradation of DEET and CAF was positively correlated with the overall consumption of total chlorine by TAN. Reactive nitrogen intermediates, including HNO/NO- and ONOOH/ONOO-, along with OH were identified as major contributors to the removal of DEET and CAF. During UV irradiation, DEET and CAF were degraded under UV/chlorine or UV/NH2Cl conditions. OH and Cl were the major reactive species to degrade DEET and CAF under UV/NH2Cl conditions, whereas OCl played a major role for degrading CAF under UV/chlorine conditions. Numerical models were developed to predict the removal of DEET and CAF under chlorination-UV process. Chlorinated disinfection byproducts were detected. Overall, this study presented kinetic features and mechanistic insights on the degradation of PPCPs under chlorine-UV process in ammoniacal water.

Sarcoendoplasmic reticulum Ca(2+) ATPase. A critical target in chlorine inhalation-induced cardiotoxicity.

PubMed

Ahmad, Shama; Ahmad, Aftab; Hendry-Hofer, Tara B; Loader, Joan E; Claycomb, William C; Mozziconacci, Olivier; Schöneich, Christian; Reisdorph, Nichole; Powell, Roger L; Chandler, Joshua D; Day, Brian J; Veress, Livia A; White, Carl W

2015-04-01

Autopsy specimens from human victims or experimental animals that die due to acute chlorine gas exposure present features of cardiovascular pathology. We demonstrate acute chlorine inhalation-induced reduction in heart rate and oxygen saturation in rats. Chlorine inhalation elevated chlorine reactants, such as chlorotyrosine and chloramine, in blood plasma. Using heart tissue and primary cardiomyocytes, we demonstrated that acute high-concentration chlorine exposure in vivo (500 ppm for 30 min) caused decreased total ATP content and loss of sarcoendoplasmic reticulum calcium ATPase (SERCA) activity. Loss of SERCA activity was attributed to chlorination of tyrosine residues and oxidation of an important cysteine residue, cysteine-674, in SERCA, as demonstrated by immunoblots and mass spectrometry. Using cardiomyocytes, we found that chlorine-induced cell death and damage to SERCA could be decreased by thiocyanate, an important biological antioxidant, and by genetic SERCA2 overexpression. We also investigated a U.S. Food and Drug Administration-approved drug, ranolazine, used in treatment of cardiac diseases, and previously shown to stabilize SERCA in animal models of ischemia-reperfusion. Pretreatment with ranolazine or istaroxime, another SERCA activator, prevented chlorine-induced cardiomyocyte death. Further investigation of responsible mechanisms showed that ranolazine- and istaroxime-treated cells preserved mitochondrial membrane potential and ATP after chlorine exposure. Thus, these studies demonstrate a novel critical target for chlorine in the heart and identify potentially useful therapies to mitigate toxicity of acute chlorine exposure.

Sarcoendoplasmic Reticulum Ca2+ ATPase. A Critical Target in Chlorine Inhalation–Induced Cardiotoxicity

PubMed Central

Ahmad, Aftab; Hendry-Hofer, Tara B.; Loader, Joan E.; Claycomb, William C.; Mozziconacci, Olivier; Schöneich, Christian; Reisdorph, Nichole; Powell, Roger L.; Chandler, Joshua D.; Day, Brian J.; Veress, Livia A.; White, Carl W.

2015-01-01

Autopsy specimens from human victims or experimental animals that die due to acute chlorine gas exposure present features of cardiovascular pathology. We demonstrate acute chlorine inhalation–induced reduction in heart rate and oxygen saturation in rats. Chlorine inhalation elevated chlorine reactants, such as chlorotyrosine and chloramine, in blood plasma. Using heart tissue and primary cardiomyocytes, we demonstrated that acute high-concentration chlorine exposure in vivo (500 ppm for 30 min) caused decreased total ATP content and loss of sarcoendoplasmic reticulum calcium ATPase (SERCA) activity. Loss of SERCA activity was attributed to chlorination of tyrosine residues and oxidation of an important cysteine residue, cysteine-674, in SERCA, as demonstrated by immunoblots and mass spectrometry. Using cardiomyocytes, we found that chlorine-induced cell death and damage to SERCA could be decreased by thiocyanate, an important biological antioxidant, and by genetic SERCA2 overexpression. We also investigated a U.S. Food and Drug Administration–approved drug, ranolazine, used in treatment of cardiac diseases, and previously shown to stabilize SERCA in animal models of ischemia–reperfusion. Pretreatment with ranolazine or istaroxime, another SERCA activator, prevented chlorine-induced cardiomyocyte death. Further investigation of responsible mechanisms showed that ranolazine- and istaroxime-treated cells preserved mitochondrial membrane potential and ATP after chlorine exposure. Thus, these studies demonstrate a novel critical target for chlorine in the heart and identify potentially useful therapies to mitigate toxicity of acute chlorine exposure. PMID:25188881

Intracellular distribution and stability of a luminescent rhenium(i) tricarbonyl tetrazolato complex using epifluorescence microscopy in conjunction with X-ray fluorescence imaging.

PubMed

Wedding, J L; Harris, H H; Bader, C A; Plush, S E; Mak, R; Massi, M; Brooks, D A; Lai, B; Vogt, S; Werrett, M V; Simpson, P V; Skelton, B W; Stagni, S

2017-04-19

Optical epifluorescence microscopy was used in conjunction with X-ray fluorescence imaging to monitor the stability and intracellular distribution of the luminescent rhenium(i) complex fac-[Re(CO) 3 (phen)L], where phen = 1,10-phenathroline and L = 5-(4-iodophenyl)tetrazolato, in 22Rv1 cells. The rhenium complex showed no signs of ancillary ligand dissociation, a conclusion based on data obtained via X-ray fluorescence imaging aligning iodine and rhenium distributions. A diffuse reticular localisation was detected for the complex in the nuclear/perinuclear region of cells, by either optical or X-ray fluorescence imaging techniques. X-ray fluorescence also showed that the rhenium complex disrupted the homeostasis of some biologically relevant elements, such as chlorine, potassium and zinc.

Toxic effects of chlorinated cake flour in rats.

PubMed

Cunningham, H M; Lawrence, G A; Tryphonas, L

1977-05-01

Four experiments were conducted using weanling Wistar rats to determine whether chlorinated cake flour or its constituents were toxic. Levels of 0.2 and 1.0% chlorine added to unbleached cake flour significantly (p less than 0.01) reduced growth rate by 20.7 and 85.2% and increased liver weight relative to body weight by 16.7 and 25.3%, respectively. Lipids extracted from flour chlorinated at the same levels had similar effects. Rat chow diets containing 0.2 and 0.6% chlorine in the form of chlorinated wheat gluten reduced growth rate and increased liver weight as a percentage of body weight. A rat chow diet containing 0.2% chlorine as chlorinated flour lipids increased absolute liver weight by 40%, kidney by 20%, and heart by 10% compared to pair-fed controls.

Acute lung injury and persistent small airway disease in a rabbit model of chlorine inhalation.

PubMed

Musah, Sadiatu; Schlueter, Connie F; Humphrey, David M; Powell, Karen S; Roberts, Andrew M; Hoyle, Gary W

2017-01-15

Chlorine is a pulmonary toxicant to which humans can be exposed through accidents or intentional releases. Acute effects of chlorine inhalation in humans and animal models have been well characterized, but less is known about persistent effects of acute, high-level chlorine exposures. In particular, animal models that reproduce the long-term effects suggested to occur in humans are lacking. Here, we report the development of a rabbit model in which both acute and persistent effects of chlorine inhalation can be assessed. Male New Zealand White rabbits were exposed to chlorine while the lungs were mechanically ventilated. After chlorine exposure, the rabbits were extubated and were allowed to survive for up to 24h after exposure to 800ppm chlorine for 4min to study acute effects or up to 7days after exposure to 400ppm for 8min to study longer term effects. Acute effects observed 6 or 24h after inhalation of 800ppm chlorine for 4min included hypoxemia, pulmonary edema, airway epithelial injury, inflammation, altered baseline lung mechanics, and airway hyperreactivity to inhaled methacholine. Seven days after recovery from inhalation of 400ppm chlorine for 8min, rabbits exhibited mild hypoxemia, increased area of pressure-volume loops, and airway hyperreactivity. Lung histology 7days after chlorine exposure revealed abnormalities in the small airways, including inflammation and sporadic bronchiolitis obliterans lesions. Immunostaining showed a paucity of club and ciliated cells in the epithelium at these sites. These results suggest that small airway disease may be an important component of persistent respiratory abnormalities that occur following acute chlorine exposure. This non-rodent chlorine exposure model should prove useful for studying persistent effects of acute chlorine exposure and for assessing efficacy of countermeasures for chlorine-induced lung injury. Copyright © 2016 Elsevier Inc. All rights reserved.

Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water.

PubMed

Mao, Guannan; Wang, Yingying; Hammes, Frederik

2018-02-01

Polymeric materials are widely used in drinking water distribution systems. These materials could release organic carbon that supports bacterial growth. To date, the available migration assays for polymeric materials have not included the potential influence of chlorination on organic carbon migration behavior. Hence, we established a migration and growth potential protocol specifically for analysis of carbon migration from materials in contact with chlorinated drinking water. Four different materials were tested, including ethylene propylene dienemethylene (EPDM), poly-ethylene (PEX b and PEX c) and poly-butylene (PB). Chlorine consumption rates decreased gradually over time for EPDM, PEXc and PB. In contrast, no free chlorine was detected for PEXb at any time during the 7 migration cycles. Total organic carbon (TOC) and assimilable organic carbon (AOC) was evaluated in both chlorinated and non-chlorinated migrations. TOC concentrations for EPDM and PEXb in chlorinated migrations were significantly higher than non-chlorinated migrations. The AOC results showed pronounced differences among tested materials. AOC concentrations from chlorinated migration waters of EPDM and PB were higher compared to non-chlorinated migrations, whereas the opposite trend was observed for PEXb and PEXc. There was also a considerable difference between tested materials with regards to bacterial growth potential. The results revealed that the materials exposed to chlorine-influenced migration still exhibited a strong biofilm formation potential. The overall results suggested that the choice in material would make a considerable difference in chlorine consumption and carbon migration behavior in drinking water distribution systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Degradation of natural organic matter by UV/chlorine oxidation: Molecular decomposition, formation of oxidation byproducts and cytotoxicity.

PubMed

Wang, Wen-Long; Zhang, Xue; Wu, Qian-Yuan; Du, Ye; Hu, Hong-Ying

2017-11-01

The degradation of natural organic matters (NOMs) by the combination of UV and chlorine (UV/chlorine) was investigated in this study. UV/chlorine oxidation can effectively degrade NOMs, with the degradation of chromophores (∼80%) and fluorophores (76.4-80.8%) being more efficient than that of DOC (15.1-18.6%). This effect was attributed to the chromophores and fluorophores (double bonds, aromatic groups and phenolic groups) being preferentially degraded by UV/chlorine oxidation, particularly reactive groups with high electron donating capacity. Radical species •OH and •Cl were generated during UV/chlorine oxidation, with the contribution of •OH 1.4 times as high as that of •Cl. The degradation kinetics of different molecular weight (MW) fractions suggests that UV/chlorine oxidation degrades high MW fractions into low MW fractions, with the degradation rates of high MW fractions (>3000 Da) 4.5 times of those of medium MW fractions (1000-3000 Da). In comparison with chlorination alone, UV/chlorine oxidation did not increase the formation (30 min) and formation potential (24 h) of trihalomethanes, but instead promoted the formation and formation potential of haloacetic acids and chloral hydrate. Adsorbable organic halogen (AOX) formed from UV/chlorine oxidation of NOM were 0.8 times higher than those formed from chlorination. Cytotoxicity studies indicated that the cytotoxicity of NOM increased after both chlorination and UV/chlorine oxidation, which may be due to the formation of AOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wedding, Jason L.; Harris, Hugh H.; Bader, Christie A.

Optical fluorescence microscopy was used in conjunction with X-ray fluorescence microscopy to monitor the stability and intracellular distribution of the luminescent rhenium(I) complex fac-[Re(CO) 3(phen)L], where phen = 1,10-phenathroline and L = 5-(4-iodophenyl)tetrazolato, in 22Rv1 cells. The rhenium complex showed no signs of ancillary ligand dissociation, a conclusion based on data obtained via X-ray fluorescence imaging aligning iodine and rhenium distributions. A diffuse reticular localisation was detected for the complex, in the nuclear/perinuclear region of cells, by either optical or X-ray fluorescence techniques. Furthermore, X-ray fluorescence also showed that the Re-I complex disrupted the homeostasis of some biologically relevant elements,more » such as chlorine, potassium and zinc.« less

Stability and effectiveness of chlorine disinfectants in water distribution systems.

PubMed

Olivieri, V P; Snead, M C; Krusé, C W; Kawata, K

1986-11-01

A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min.

Stability and effectiveness of chlorine disinfectants in water distribution systems.

PubMed Central

Olivieri, V P; Snead, M C; Krusé, C W; Kawata, K

1986-01-01

A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min. PMID:3028767

40 CFR 141.65 - Maximum residual disinfectant levels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... MRDL (mg/L) Chlorine 4.0 (as Cl2). Chloramines 4.0 (as Cl2). Chlorine dioxide 0.8 (as ClO2). (b... chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and using chlorine dioxide as a...

Formation of trichloromethane in chlorinated water and fresh-cut produce and as a result of reacting with citric acid

USDA-ARS?s Scientific Manuscript database

Chlorine (sodium hypochlorite) is commonly used by the fresh produce industry to sanitize wash water, fresh and fresh-cut fruits and vegetables. However, possible formation of harmful chlorine by-products is a concern. The objectives of this study were to compare chlorine and chlorine dioxide in t...

75 FR 49464 - Chlorinated Isocyanurates from Spain and the People's Republic of China: Final Results of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

... DEPARTMENT OF COMMERCE International Trade Administration A-469-814, A-570-898 Chlorinated... sunset reviews of the antidumping duty orders on chlorinated isocyanurates (``chlorinated isos'') from... chlorinated isos from Spain and the PRC, pursuant to section 751(c)(3)(B) of the Act and 19 CFR 351.218(e)(1...

State of the art on cyanotoxins in water and their behaviour towards chlorine.

PubMed

Merel, Sylvain; Clément, Michel; Thomas, Olivier

2010-04-01

The occurrence of cyanobacterial blooms is drastically increasing in temperate countries and drinking water resources are threatened. As a result, cyanotoxins should be considered in water treatment to protect human health. This study presents a state of the art on cyanotoxins in water and their behaviour towards chlorination, a common drinking water disinfection process. Chlorination efficiency on cyanotoxins alteration depends on pH, chlorine dose and oxidant nature. Microcystins and cylindrospermopsin are efficiently transformed by chlorine, with respectively 6 and 2 by-products identified. In addition, chlorination of microcystins and cylindrospermopsin is associated with a loss of acute toxicity. Even though they have been less investigated, saxitoxins and nodularins are also altered by chlorine. For these toxins, no by-products have been identified, but the chlorinated mixture does not show acute toxicity. On the contrary, the fact that anatoxin-a has a very slow reaction kinetics suggests that this toxin resists chlorination. Copyright 2009 Elsevier Ltd. All rights reserved.

Effects of UV 254 irradiation on residual chlorine and DBPs in chlorination of model organic-N precursors in swimming pools.

PubMed

Weng, ShihChi; Li, Jing; Blatchley, Ernest R

2012-05-15

Ultraviolet (UV) irradiation is commonly applied as a secondary disinfection process in chlorinated pools. UV-based systems have been reported to yield improvements in swimming pool water and air chemistry, but to date these observations have been largely anecdotal. The objectives of this investigation were to evaluate the effects of UV irradiation on chlorination of important organic-N precursors in swimming pools. Creatinine, L-arginine, L-histidine, glycine, and urea, which comprise the majority of the organic-N in human sweat and urine, were selected as precursors for use in conducting batch experiments to examine the time-course behavior of several DBPs and residual chlorine, with and without UV(254) irradiation. In addition, water samples from two natatoria were subjected to monochromatic UV irradiation at wavelengths of 222 nm and 254 nm to evaluate changes of liquid-phase chemistry. UV(254) irradiation promoted formation and/or decay of several chlorinated N-DBPs and also increased the rate of free chlorine consumption. UV exposure resulted in loss of inorganic chloramines (e.g., NCl(3)) from solution. Dichloromethylamine (CH(3)NCl(2)) formation from creatinine was promoted by UV exposure, when free chlorine was present in solution; however, when free chlorine was depleted, CH(3)NCl(2) photodecay was observed. Dichloroacetonitrile (CNCHCl(2)) formation (from L-histidine and L-arginine) was promoted by UV(254) irradiation, as long as free chlorine was present in solution. Likewise, UV exposure was observed to amplify cyanogen chloride (CNCl) formation from chlorination of L-histidine, L-arginine, and glycine, up to the point of free chlorine depletion. The results from experiments involving UV irradiation of chlorinated swimming pool water were qualitatively consistent with the results of model experiments involving UV/chlorination of precursors in terms of the behavior of residual chlorine and DBPs measured in this study. The results indicate that UV(254) irradiation promotes several reactions that are involved in the formation and/or destruction of chlorinated N-DBPs in pool settings. Enhancement of DBP formation was consistent with a mechanism whereby a rate-limiting step in DBP formation was promoted by UV exposure. Promotion of these reactions also resulted in increases of free chlorine consumption rates. Copyright © 2012 Elsevier Ltd. All rights reserved.

Polychlorinated biphenyl toxicity to Japanese quail as related to degree of chlorination

USGS Publications Warehouse

Hill, E.F.; Heath, R.G.; Spann, J.W.; Williams, J.D.

1974-01-01

To learn if the percentage of chlorine in a mixture of polychlorinated biphenyls (PCB's) alone determines toxicity, Japanese quail were fed diets containing Aroelor 1248, 1254, or 1260 at levels that added equal amounts of chlorine to the feed. The experiment comprised two consecutive 5-day periods; three sublethal concentrations of chlorine were evaluated during the first period and three lethal concentrations during the second period. Evaluations utilized comparisons of mortality, time to death, weight change, and food consumption. Sublethal concentrations produced no detectable effects. Lethal concentrations with equal Chlorine showed Aroelor 1248 to be less toxic at the highest chlorine concentrations, but at lower concentrations Aroelor 1254 was more toxic than Aroclor 1260. Although chlorine percentage of a PCB is positively correlated with its avian toxicity, PCB toxicity is apparently not simply a function of chlorination.

Semiempirical Quantum Chemistry Model for the Lanthanides: RM1 (Recife Model 1) Parameters for Dysprosium, Holmium and Erbium

PubMed Central

Filho, Manoel A. M.; Dutra, José Diogo L.; Rocha, Gerd B.; Simas, Alfredo M.; Freire, Ricardo O.

2014-01-01

Complexes of dysprosium, holmium, and erbium find many applications as single-molecule magnets, as contrast agents for magnetic resonance imaging, as anti-cancer agents, in optical telecommunications, etc. Therefore, the development of tools that can be proven helpful to complex design is presently an active area of research. In this article, we advance a major improvement to the semiempirical description of lanthanide complexes: the Recife Model 1, RM1, model for the lanthanides, parameterized for the trications of Dy, Ho, and Er. By representing such lanthanide in the RM1 calculation as a three-electron atom with a set of 5 d, 6 s, and 6 p semiempirical orbitals, the accuracy of the previous sparkle models, mainly concentrated on lanthanide-oxygen and lanthanide-nitrogen distances, is extended to other types of bonds in the trication complexes’ coordination polyhedra, such as lanthanide-carbon, lanthanide-chlorine, etc. This is even more important as, for example, lanthanide-carbon atom distances in the coordination polyhedra of the complexes comprise about 30% of all distances for all complexes of Dy, Ho, and Er considered. Our results indicate that the average unsigned mean error for the lanthanide-carbon distances dropped from an average of 0.30 Å, for the sparkle models, to 0.04 Å for the RM1 model for the lanthanides; for a total of 509 such distances for the set of all Dy, Ho, and Er complexes considered. A similar behavior took place for the other distances as well, such as lanthanide-chlorine, lanthanide-bromine, lanthanide, phosphorus and lanthanide-sulfur. Thus, the RM1 model for the lanthanides, being advanced in this article, broadens the range of application of semiempirical models to lanthanide complexes by including comprehensively many other types of bonds not adequately described by the previous models. PMID:24497945

The gas fluxing of aluminum: Mathematical modeling and experimental investigations

NASA Astrophysics Data System (ADS)

Fjeld, Autumn Marie

Chlorine fluxing is an essential purification step in aluminum refining in which impurities such as Ca, Na, Li, and Mg are removed by bubbling a mixture of chlorine and argon gas through molten aluminum. The gas is injected into the fluxing vessel through a rotating shaft and impeller which simultaneously agitates the melt, while breaking up and dispersing gas bubbles through the liquid phase. The efficiency of impurity removal and control of toxic chlorine and chloride emissions are dependent upon the extent of gas dispersion or mixing, residence time of the bubbles, and surface area of the bubbles. Clearly the gas injection and distribution within the liquid metal cannot be directly observed and such operations are often poorly controlled and not well understood. Problems arise when the injection gas, i.e. chlorine, is not completely consumed by reaction with impurities and the excess is reported as emissions of chlorides such as toxic HCl. The intention is to improve the technology to eliminate this waste (saving on the energy entailed in the chlorine production and reducing pollution) by better dispersion of the injected gas throughout the metal. Previous experimental investigations using a capacitance probe, capable of immersion in liquid aluminum for several hours, have been carried out to detect bubbles in an industrial fluxing unit at the Alcoa Technical Center. Bubble frequency data have shown the bubbles to be fairly well dispersed in the areas of the fluxing unit, decreasing in observed bubble frequency with increasing distance from the impeller (source of gas injection). To gain further insight and add to our experimental findings, two computational models have been developed to simulate the complex two-phase fluid dynamics of a rotary gas injection system. The results of these two modeling approaches are presented and analyzed and compared to experimental bubble measurements gathered using the capacitance probe. Bubble size distributions and residence times from the discrete phase model were incorporated in an external demagging reaction model to predict chlorine utilization efficiency. This simplified model included several assumptions regarding the kinetics and reaction path, however the model showed reasonable agreement to prior experimental magnesium removal data and provides valuable information related to the interplay of reaction progress in a fluxing unit and the fluid dynamics, in terms of bubble size, trajectory and resulting bubble residence time.

Chlorinated and parent polycyclic aromatic hydrocarbons in environmental samples from an electronic waste recycling facility and a chemical industrial complex in China.

PubMed

Ma, Jing; Horii, Yuichi; Cheng, Jinping; Wang, Wenhua; Wu, Qian; Ohura, Takeshi; Kannan, Kurunthachalam

2009-02-01

Chlorinated polycyclic aromatic hydrocarbons (CIPAHs) are a class of halogenated contaminants found in the urban atmosphere; they have toxic potential similar to that of dioxins. Information on the sources of CIPAHs is limited. In this study, concentrations of 20 CIPAHs and 16 parent PAHs were measured in electronic wastes, workshop-floor dust, vegetation, and surface soil collected from the vicinity of an electronic waste (e-waste) recycling facility and in surface soil from a chemical industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant), and agricultural areas in central and eastern China. High concentrations of SigmaCIPAHs were found in floor dust (mean, 103 ng/g dry wt), followed in order of decreasing concentration by leaves (87.5 ng/g drywt), electronic shredder waste (59.1 ng/g dry wt), and soil (26.8 ng/g dry wt) from an e-waste recycling facility in Taizhou. The mean concentration of SigmaCIPAHs in soil from the chemical industrial complex (88 ng/g dry wt) was approximately 3-fold higher than the concentration in soil from e-waste recycling facilities. The soils from e-waste sites and industrial areas contained mean concentrations of SigmaCIPAHs 2 to 3 orders of magnitude higher than the concentrations in agricultural soils (ND-0.76 ng/g), suggesting that e-waste recycling and chlorine-chemical industries are potential emission sources of CIPAHs. The profiles of CIPAHs in soil and dust were similar to a profile that has been reported previously for fly ash from municipal solid waste incinerators (6-CIBaP was the predominant compound), but the profiles in vegetation and electronic shredder waste were different from those found in fly ash. Concentrations of 16 parent PAHs were high (150-49,700 ng/g) in samples collected from the e-waste recycling facility. Significant correlation between SigmaCIPAH and SigmaPAH concentrations suggests that direct chlorination of parent PAHs is the major pathway of formation of CIPAHs during e-waste recycling operations. Dioxin-like toxic equivalency quotients (TEQs) for CIPAHs and PAHs in samples were calculated on the basis of relative potencies reported for CIPAHs and PAHs. The highest mean TEQ concentrations of CIPAHs (518 pg-TEQ/g) were found for workshop-floor dust, followed by leaves (361 pg-TEQ/g), electronic shredder waste (308 pg-TEQ/g), soil from the chemical industrial complex (146 pg-TEQ/g), and soil from the sites of the e-waste recycling facility (92.3 pg-TEQ/g). With one exception, the floor dust samples, the TEQ concentrations of CIPAHs found in multiple environmental matrices in this study were higher than the TEQ concentrations of PCDD/Fs in the same samples reported in our earlier study.

Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

PubMed Central

Taylor, Robert H.; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

2000-01-01

Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains were more resistant to chlorine than were cells of the more rapidly growing strains. Water-grown cells were 10-fold more resistant than medium-grown cells. Disinfectant resistance may be one factor promoting the persistence of M. avium in drinking water. PMID:10742264

Stepwise syntheses of bisporphyrins, bischlorins, and biscorroles and of porphyrin-chlorin and porphyrin-corrole heterodimers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paolesse, R.; Pandey, R.K.; Forsyth, T.P.

The stepwise syntheses and characterization of a series of symmetrical and unsymmetrical bisporphyrins, bischlorins, and biscorroles, and of porphyrin-chlorin and porphyrin-corrole dyads possessing ethylene, phenyl, and stilbene linking units are described. The methodology for synthesis of 10-substituted corroles 2 and their cobalt complexes 9 via a,c-biladiene salts 1 was first developed, and then extended to provide biscorroles (e.g., 4 and 5) linked through the 10-positions with phenyl linker units. Using a similar methodology, phenyl-linked corrole-porphyrin dyads 28 and 30 were also prepared. By way of intermediate phenyl-linked unsymmetrical bisdipyrromethanes, a completely unsymmetrical heterobimetallic bisporphyrin system, 45, was synthesized. Low-valent titaniummore » coupling (McMurry) reactions were used to prepare stilbene-linked bisdipyrromethanes (e.g., 46) which were subsequently transformed into stilbene-linked bisporphyrins (e.g., 48). McMurry cross-coupling reactions of porphyrins bearing p-formylphenyl substituents also afforded an unsymmetrically substituted bisporphyrinylstilbene, 60, as well as the corresponding homodimers 56 and 59. Likewise, McMurry cross-coupling of a p-formylphenyl-substituted porphyrin, 62, with a formylchlorin, 63, afforded a stilbene-linked bisporphyrin, 64, a bischlorin, 66, and a novel porphyrin-chlorin heterodimer, 65. 54 refs., 1 fig., 1 tab.« less

Large-eddy simulations of a solid-rocket booster jet

NASA Astrophysics Data System (ADS)

Paoli, Roberto; Poubeau, Adele; Cariolle, Daniel

2014-11-01

Emissions from solid-rocket boosters are responsible for a severe decrease in ozone concentration in the rocket plume during the first hours after a launch. The main source of ozone depletion is due to hydrogen chloride that is converted into chlorine in the high temperature regions of the jet (afterburning). The objective of this study is to evaluate the active chlorine concentration in the plume of a solid-rocket booster using large-eddy simulations. The gas is injected through the entire nozzle of the booster and a local time-stepping method based on coupling multi-instances of a fluid solver is used to extend the computational domain up to 600 nozzle exit diameters. The methodology is validated for a non-reactive case by analyzing the flow characteristics of supersonic co-flowing under expanded jets. Then, the chemistry of chlorine is studied offline using a complex chemistry solver and the LES data extracted from the mean trajectories of sample fluid particles. Finally, the online chemistry is analyzed by means of the multispecies version of the LES solver using a reduced chemistry scheme. The LES are able to capture the mixing of the exhaust with ambient air and the species concentrations, which is also useful to initialize atmospheric simulations on larger domains.

A molecular beam mass spectrometric study of the formation and photolysis of C(lc)lO dimer

NASA Technical Reports Server (NTRS)

Greene, Frank T.; Robaugh, David A.

1992-01-01

A study of the chlorine oxides present at temperatures and pressures typical of the Antarctic stratosphere was carried out. A series of low temperature flow reactors was constructed and used in conjunction with molecular beam mass spectrometric techniques to identify species and characterize their kinetic behavior at temperatures of -20 to -70 C and pressures of from 30 to 130 Torr. It was found that the gas phase chlorine-oxygen system was quite complex at low temperatures. ClO dimer was identified and found to be thermodynamically very stable under stratospheric conditions. It was also found that any system which contained ClO also contained a larger oxide. The oxide was identified as Cl2O3. A survey of possible higher oxides, which have been postulated as possible chlorine sinks in the stratosphere, was also carried out. The rate of formation of ClO dimer was measured as a function of temperature and pressure. Measurements were made of both the decay of ClO and the formation of the dimer. By comparing these rates it was determined that virtually all of the ClO was converted to the dimer under stratospheric conditions, and that the other ClO reactions were not important under these conditions.

Chlorine-36 dating of saline sediments: Preliminary results from Searles Lake, California

USGS Publications Warehouse

Phillips, F.M.; Smith, G.I.; Bentley, H.W.; Elmore, D.; Gove, H.E.

1983-01-01

Measurements have been made of the ratios of chlorine-36 to chlorine in five halite samples from Searles Lake sediments, previously dated by carbon-14, thorium-230, and magnetostratigraphic techniques. The ages calculated from the chlorine ratios are generally concordant with those from the other methods, implying the constancy of the chlorine input ratio over the last million years.

Role of drinking water biofilms on residual chlorine decay and trihalomethane formation: An experimental and modeling study.

PubMed

Xu, Jianeng; Huang, Conghui; Shi, Xiaoyang; Dong, Shengkun; Yuan, Baoling; Nguyen, Thanh H

2018-06-13

PVC pipe loops were constructed to simulate household premise plumbing. These pipe loops were exposed to water treated by physical processes at three water treatment plants in Xiamen, China from August 2016 to June 2017. After the biofilms were allowed to develop inside the pipes, these pipes were deconstructed and exposed to organic-free chlorine solution buffered at pH 6.8 ± 0.2 for 48 h. The decay of chlorine by these biofilms was higher than by the effluent waters that were used to grow the biofilms. A chlorine consumption mass balance model elucidated the role of both the diffusion of chlorine into the biofilm and the reaction of chlorine with the biofilm matrix. Comparable concentrations of trihalomethanes were quantified from the reaction between chlorine and source water organic matters, and chlorine and the biofilm, further emphasizing the role of biofilms in the safety of disinfected drinking water. These findings imply that when chlorine is used in the drinking water distribution system, the ubiquitous presence of biofilms may cause the depletion of chlorine and the formation of non-negligible levels of toxic disinfection byproducts. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of Multiple Environmental Factors on Organic Matter Chlorination in Podsol Soil.

PubMed

Svensson, Teresia; Montelius, Malin; Andersson, Malin; Lindberg, Cecilia; Reyier, Henrik; Rietz, Karolina; Danielsson, Åsa; Bastviken, David

2017-12-19

Natural chlorination of organic matter is common in soils. The abundance of chlorinated organic compounds frequently exceeds chloride in surface soils, and the ability to chlorinate soil organic matter (SOM) appears widespread among microorganisms. Yet, the environmental control of chlorination is unclear. Laboratory incubations with 36 Cl as a Cl tracer were performed to test how combinations of environmental factors, including levels of soil moisture, nitrate, chloride, and labile organic carbon, influenced chlorination of SOM from a boreal forest. Total chlorination was hampered by addition of nitrate or by nitrate in combination with water but enhanced by addition of chloride or most additions including labile organic matter (glucose and maltose). The greatest chlorination was observed after 15 days when nitrate and water were added together with labile organic matter. The effect that labile organic matter strongly stimulated the chlorination rates was confirmed by a second independent experiment showing higher stimulation at increased availability of labile organic matter. Our results highlight cause-effect links between chlorination and the studied environmental variables in podsol soil-with consistent stimulation by labile organic matter that did overrule the negative effects of nitrate.

Evaluating four measures of water quality in clay pots and plastic safe storage containers in Kenya.

PubMed

Murphy, Jennifer L; Ayers, Tracy L; Knee, Jacqueline; Oremo, Jared; Odhiambo, Aloyce; Faith, Sitnah H; Nyagol, Ronald O; Stauber, Christine E; Lantagne, Daniele S; Quick, Robert E

2016-11-01

Household water treatment with chlorine can improve microbiological quality and reduce diarrhea. Chlorination is typically assessed using free chlorine residual (FCR), with a lower acceptable limit of 0.2 mg/L, however, accurate measurement of FCR is challenging with turbid water. To compare potential measures of adherence to treatment and water quality, we chlorinated recently-collected water in rural Kenyan households and measured total chlorine residual (TCR), FCR, oxidation reduction potential (ORP), and E. coli concentration over 72 h in clay and plastic containers. Results showed that 1) ORP served as a useful proxy for chlorination in plastic containers up to 24 h; 2) most stored water samples disinfected by chlorination remained significantly less contaminated than source water for up to 72 h, even in the absence of FCR; 3) TCR may be a useful proxy indicator of microbiologic water quality because it confirms previous chlorination and is associated with a lower risk of E. coli contamination compared to untreated source water; and 4) chlorination is more effective in plastic than clay containers presumably because of lower chlorine demand in plastic. Published by Elsevier Ltd.

Different removal behaviours of multiple trace antibiotics in municipal wastewater chlorination.

PubMed

Li, Bing; Zhang, Tong

2013-06-01

The chlorination behaviours of 12 antibiotics belonging to six classes at environmentally relevant concentrations were systematically examined under typical conditions relevant to municipal wastewater chlorination. Cefotaxime, cefalexin, ampicillin and tetracycline were completely removed under all three initial free chlorine dosages (5 mg/L, 10 mg/L, and 15 mg/L). The removal efficiencies of sulphamethoxazole, sulphadiazine, roxithromycin, anhydro-erythromycin, ofloxacin, and trimethoprim were closely correlated to the residual free chlorine concentration, and no further significant mass removal was observed after the residual free chlorine concentration decreased to less than ≈ 0.75 mg/L. Ammonia plays a critical role during chlorination because of its competition with antibiotics for free chlorine to form combined chlorine, which reacts slowly with these antibiotics. Except for norfloxacin and ciprofloxacin, the removal behaviours of the 10 other target antibiotics under ammonia nitrogen concentrations ranging from 2 to 15 mg/L were characterised by a rapid initial removal rate upon contact with free chlorine during the first 5 s-1 min (depending on the specific antibiotic and ammonia nitrogen concentration) and then a much slower removal rate. Free chlorine was responsible for the reaction with antibiotics during the rapid stage (first 5 s-1 min), whereas combined chlorine reacted with antibiotics in the subsequent slow stage. Combined chlorine can remove norfloxacin and ciprofloxacin at a relatively faster rate. The presence of suspended solids at 30 mg/L slightly decreased the antibiotic removal rate. The kinetic rate constants decreased by 2.1-13.9%, while the half-lives increased by 2.0-15.0% compared to those of a 0 mg/L suspended solid for the target antibiotics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

PubMed

Xiang, Yingying; Fang, Jingyun; Shang, Chii

2016-03-01

The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed. Copyright © 2015 Elsevier Ltd. All rights reserved.

UV/chlorine as an advanced oxidation process for the degradation of benzalkonium chloride: Synergistic effect, transformation products and toxicity evaluation.

PubMed

Huang, Nan; Wang, Ting; Wang, Wen-Long; Wu, Qian-Yuan; Li, Ang; Hu, Hong-Ying

2017-05-01

Benzalkonium chlorides (BACs), as typical cationic surfactants and biocides widely applied in household and industrial products, have been frequently detected as micropollutants in many aquatic environments. In this study, the combination of UV irradiation and chlorine (UV/chlorine), a newly interested advanced oxidation process, was used to degrade dodecylbenzyldimethylammonium chloride (DDBAC). UV/chlorine showed synergistic effects on DDBAC degradation comparing to UV irradiation or chlorination alone. Radical quenching experiments indicated that degradation of DDBAC by UV/chlorine involved both UV photolysis and radical species oxidation, which accounted for 48.4% and 51.6%, respectively. Chlorine dosage and pH are essential parameters affecting the treatment efficiency of UV/chlorine. The pseudo first order rate constant (k obs, DDBAC ) increased from 0.046 min -1 to 0.123 min -1 in response to chlorine dosage at 0-150 mg/L, and the degradation percentage of DDBAC within 12 min decreased from 81.4% to 56.6% at pH 3.6-9.5. Five main intermediates were identified and semi-quantified using HPLC-MS/MS and a possible degradation pathway was proposed. The degradation mechanisms of DDBAC by UV/chlorine included cleavage of the benzyl-nitrogen bond and hydrogen abstraction of the alkyl chain. Trichloromethane (TCM), chloral hydrate (CH), trichloropropanone (TCP), dichloropropanone (DCP) and dichloroacetonitrile (DCAN) were detected using GC-ECD. The formation of chlorinated products increased rapidly initially, then decreased (TCM, TCP, DCP and DCAN) or remained stable (CH) with extended treatment. The actual formation of TCM peaked at 30 min (50.3 μg/L), while other chlorinated products did not exceed 10 μg/L throughout the process. Based on the luminescent bacterial assay, DDBAC solution underwent almost complete detoxification subjected to UV/chlorine treatment for 120 min, which is more effective than UV irradiation or chlorination alone. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inactivation of Aspergillus flavus in drinking water after treatment with UV irradiation followed by chlorination.

PubMed

Al-Gabr, Hamid Mohammad; Zheng, Tianling; Yu, Xin

2013-10-01

The disinfection process for inactivating microorganisms at drinking water treatment plants is aimed for safety of drinking water for humans from a microorganism, such as bacteria, viruses, algae, fungi by using chlorination, ozonation, UV irradiation, etc. In the present study, a combination of two disinfectants, UV irradiation followed by chlorination, was evaluated for inactivating Aspergillus flavus under low contact time and low dosage of UV irradiation. The results indicated an inverse correlation between the inactivation of A. flavus by using UV irradiation only or chlorination alone. By using UV radiation, the 2 log10 control of A. flavus was achieved after 30 s of irradiation, while chlorination was observed to be more effective than UV, where the 2 log was achieved at chlorine concentration of 0.5, 1, 2 and 3 mg/l, in contact time of 60, 5, 1 and 1 min, respectively. However, combined use (UV irradiation followed by chlorination) was more effective than using either UV or chlorination alone; 5 s UV irradiation followed by chlorination produced 4 log10 reduction of A. flavus at chlorine concentrations of 2 and 3 mg/l under a contact time of 15 min. The results indicated that efficiency of UV irradiation improves when followed by chlorination at low concentrations. Copyright © 2013 Elsevier B.V. All rights reserved.

Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

PubMed

Powell, Joshua; Luh, Jeanne; Coronell, Orlando

2014-01-01

We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

[Inactivation of Mycobacteria mucogenicum in drinking water: chlorine resistance and mechanism analysis].

PubMed

Zheng, Qi; Chen, Chao; Zhang, Xiao-Jian; Lu, Pin-Pin; Liu, Yuan-Yuan; Chen, Yu-Qiao

2013-02-01

In recent years, chlorine-resistant bacteria were detected in drinking water distribution systems which threatened the drinking water safety. Our group detected one strain named Mycobacteria mucogenicum from the drinking water distribution system of a city in south China. This paper studied chlorine resistance and mechanism of Mycobacteria mucogenicum. Inactivation experiments of one strain Mycobacteria mucogenicum were conducted with free chlorine, monochloramind and chlorine dioxide. The CT values of 99.9% inactivation by free chlorine, monochloramine and chlorine dioxide were detected as (76.25 +/- 47.55)mg.min.L-1, (1396 +/-382)mg.min.L-1, (13.5 +/- 4.9) mg.min L-1. Using transmission electronmicroscopy (TEM) observed the inactivation process of Mycobacteria mucogenicum. The bacteria surface hydrophobic of Mycobacteria mucogenicum was 37.2%. Mycobacteria mucogenicum has a higher hydrophobicity than other bacteria which prevented the diffusion of chlorine into cells. Mycobacteria mucogenicum is more resistant to chorine than other bacteria.

Relative reactivity of amino acids with chlorine in mixtures.

PubMed

Na, Chongzheng; Olson, Terese M

2007-05-01

The relative reactivity of chlorine with amino acids is an important determinant of the resulting chlorination products in systems where chlorine is the limiting reagent, for example, in the human gastrointestinal tract after consumption of chlorine-containing water, or during food preparation with chlorinated water. Since few direct determinations of the initial reactivity of chlorine with amino acids have been made, 17 amino acids were compared in this study using competitive kinetic principles. The experimental results showed that (1) most amino acids have similar initial reactivities at neutral pH; (2) amino acids with thiol groups such as methionine and cysteine are exceptionally reactive and produce sulfoxides; (3) amino acids without thiol groups primarily undergo monochlorination of the amino nitrogen; and (4) glycine and proline are the least reactive. Dichlorination was estimated to occur with approximately 26% of the amino acid groups when the total amino acid: chlorine concentrations were equal.

Degradation of chloramphenicol by UV/chlorine treatment: Kinetics, mechanism and enhanced formation of halonitromethanes.

PubMed

Dong, Huiyu; Qiang, Zhimin; Hu, Jun; Qu, Jiuhui

2017-09-15

Ultraviolet (UV)/chlorine process is considered as an emerging advanced oxidation process for the degradation of micropollutants. This study investigated the degradation of chloramphenicol (CAP) and formation of disinfection by-products (DBPs) during the UV/chlorine treatment. It was found that CAP degradation was enhanced by combined UV/chlorine treatment compared to that of UV and chlorination treatment alone. The pseudo-first-order rate constant of the UV/chlorine process at pH 7.0 reached 0.016 s -1 , which was 10.0 and 2.0 folds that observed from UV and chlorination alone, respectively. The enhancement can be attributed to the formation of diverse radicals (HO and reactive chlorine species (RCSs)), and the contribution of RCSs maintained more stable than that of HO at pH 5.5-8.5. Meanwhile, enhanced DBPs formation during the UV/chlorine treatment was observed. Both the simultaneous formation and 24-h halonitromethanes formation potential (HNMsFP) were positively correlated with the UV/chlorine treatment time. Although the simultaneous trichloronitromethane (TCNM) formation decreased with the prolonged UV irradiation, TCNM dominated the formation of HNMs after 24 h (>97.0%). According to structural analysis of transformation by-products, both the accelerated CAP degradation and enhanced HNMs formation steps were proposed. Overall, the formation of diverse radicals during the UV/chlorine treatment accelerated the degradation of CAP, while also enhanced the formation of DBPs simultaneously, indicating the need for DBPs evaluation before the application of combined UV/chlorine process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Variations in Stratospheric Inorganic Chlorine Between 1991 and 2006

NASA Technical Reports Server (NTRS)

Lary, D. J.; Waugh, D. W.; Douglass, A. R.; Stolarski, R. S.; Newman, P. A.; Mussa, H.

2007-01-01

So how quickly will the ozone hole recover? This depends on how quickly the chlorine content (Cl2) of the atmosphere will decline. The ozone hole forms over the Antarctic each southern spring (September and October). The extremely small ozone amounts in the ozone hole are there because of chemical reactions of ozone with chlorine. This chlorine originates largely from industrially produced chlorofluorocarbon (CFC) compounds. An international agreement, the Montreal Protocol, is drastically reducing the amount of chlorine-containing compounds that we are releasing into the atmosphere. To be able to attribute changes in stratospheric ozone to changes in chlorine we need to know the distribution of atmospheric chlorine. However, due to a lack of continuous observations of all the key chlorine gases, producing a continuous time series of stratospheric chlorine has not been achieved to date. We have for the first time devised a technique to make a 17-year time series for stratospheric chlorine that uses the long time series of HCl observations made from several space borne instruments and a neural network. The neural networks allow us to both inter-calibrate the various HCl instruments and to infer the total amount of atmospheric chlorine from HCl. These new estimates of Cl, provide a much needed critical test for current global models that currently predict significant differences in both Cl(sub y) and ozone recovery. These models exhibit differences in their projection of the recovery time and our chlorine content time series will help separate the good from the bad in these projections.

Formation and control of disinfection byproducts and toxicity during reclaimed water chlorination: A review.

PubMed

Du, Ye; Lv, Xiao-Tong; Wu, Qian-Yuan; Zhang, Da-Yin; Zhou, Yu-Ting; Peng, Lu; Hu, Hong-Ying

2017-08-01

Chlorination is essential to the safety of reclaimed water; however, this process leads to concern regarding the formation of disinfection byproducts (DBPs) and toxicity. This study reviewed the formation and control strategies for DBPs and toxicity in reclaimed water during chlorination. Both regulated and emerging DBPs have been frequently detected in reclaimed water during chlorination at a higher level than those in drinking water, indicating they pose a greater risk to humans. Luminescent bacteria and Daphnia magna acute toxicity, anti-estrogenic activity and cytotoxicity generally increased after chlorination because of the formation of DBPs. Genotoxicity by umu-test and estrogenic activity were decreased after chlorination because of destruction of toxic chemicals. During chlorination, water quality significantly impacted changes in toxicity. Ammonium tended to attenuate toxicity changes by reacting with chlorine to form chloramine, while bromide tended to aggravate toxicity changes by forming hypobromous acid. During pretreatment by ozonation and coagulation, disinfection byproduct formation potential (DBPFP) and toxicity formation potential (TFP) occasionally increase, which is accompanied by DOC removal; thus, the decrease of DOC was limited to indicate the decrease of DBPFP and TFP. It is more important to eliminate the key fraction of precursors such as hydrophobic acid and hydrophilic neutrals. During chlorination, toxicities can increase with the increasing chlorine dose and contact time. To control the excessive toxicity formation, a relatively low chlorine dose and short contact time were required. Quenching chlorine residual with reductive reagents also effectively abated the formation of toxic compounds. Copyright © 2017. Published by Elsevier B.V.

Formation of assimilable organic carbon during oxidation of natural waters with ozone, chlorine dioxide, chlorine, permanganate, and ferrate.

PubMed

Ramseier, Maaike K; Peter, Andreas; Traber, Jacqueline; von Gunten, Urs

2011-02-01

Five oxidants, ozone, chlorine dioxide, chlorine, permanganate, and ferrate were studied with regard to the formation of assimilable organic carbon (AOC) and oxalate in absence and presence of cyanobacteria in lake water matrices. Ozone and ferrate formed significant amounts of AOC, i.e. more than 100 μg/L AOC were formed with 4.6 mg/L ozone and ferrate in water with 3.8 mg/L dissolved organic carbon. In the same water samples chlorine dioxide, chlorine, and permanganate produced no or only limited AOC. When cyanobacterial cells (Aphanizomenon gracile) were added to the water, an AOC increase was detected with ozone, permanganate, and ferrate, probably due to cell lysis. This was confirmed by the increase of extracellular geosmin, a substance found in the selected cyanobacterial cells. AOC formation by chlorine and chlorine dioxide was not affected by the presence of the cells. The formation of oxalate upon oxidation was found to be a linear function of the oxidant consumption for all five oxidants. The following molar yields were measured in three different water matrices based on oxidant consumed: 2.4-4.4% for ozone, 1.0-2.8% for chlorine dioxide and chlorine, 1.1-1.2% for ferrate, and 11-16% for permanganate. Furthermore, oxalate was formed in similar concentrations as trihalomethanes during chlorination (yield ∼ 1% based on chlorine consumed). Oxalate formation kinetics and stoichiometry did not correspond to the AOC formation. Therefore, oxalate cannot be used as a surrogate for AOC formation during oxidative water treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Abnormal epithelial structure and chronic lung inflammation after repair of chlorine-induced airway injury

PubMed Central

Mo, Yiqun; Chen, Jing; Humphrey, David M.; Fodah, Ramy A.; Warawa, Jonathan M.

2014-01-01

Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical threat agent. High-level chlorine exposure causes acute lung injury, but the long-term effects of acute chlorine exposure are unclear. Here we characterized chronic pulmonary changes following acute chlorine exposure in mice. A/J mice were exposed to 240 parts per million-hour chlorine or sham-exposed to air. Chlorine inhalation caused sloughing of bronchial epithelium 1 day after chlorine exposure, which was repaired with restoration of a pseudostratified epithelium by day 7. The repaired epithelium contained an abnormal distribution of epithelial cells containing clusters of club or ciliated cells rather than the uniformly interspersed pattern of these cells in unexposed mice. Although the damaged epithelium in A/J mice was repaired rapidly, and minimal airway fibrosis was observed, chlorine-exposed mice developed pneumonitis characterized by infiltration of alveoli with neutrophils and prominent, large, foamy macrophages. Levels of CXCL1/KC, CXCL5/LPS-induced CXC chemokine, granulocyte colony-stimulating factor, and VEGF in bronchoalveolar (BAL) fluid from chlorine-exposed mice showed steadily increasing trends over time. BAL protein levels were increased on day 4 and remained elevated out to day 28. The number of bacteria cultured from lungs of chlorine-exposed mice 4 wk after exposure was not increased compared with sham-exposed mice, indicating that the observed pneumonitis was not driven by bacterial infection of the lung. The results indicate that acute chlorine exposure may cause chronic abnormalities in the lungs despite rapid repair of injured epithelium. PMID:25398987

Abnormal epithelial structure and chronic lung inflammation after repair of chlorine-induced airway injury.

PubMed

Mo, Yiqun; Chen, Jing; Humphrey, David M; Fodah, Ramy A; Warawa, Jonathan M; Hoyle, Gary W

2015-01-15

Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical threat agent. High-level chlorine exposure causes acute lung injury, but the long-term effects of acute chlorine exposure are unclear. Here we characterized chronic pulmonary changes following acute chlorine exposure in mice. A/J mice were exposed to 240 parts per million-hour chlorine or sham-exposed to air. Chlorine inhalation caused sloughing of bronchial epithelium 1 day after chlorine exposure, which was repaired with restoration of a pseudostratified epithelium by day 7. The repaired epithelium contained an abnormal distribution of epithelial cells containing clusters of club or ciliated cells rather than the uniformly interspersed pattern of these cells in unexposed mice. Although the damaged epithelium in A/J mice was repaired rapidly, and minimal airway fibrosis was observed, chlorine-exposed mice developed pneumonitis characterized by infiltration of alveoli with neutrophils and prominent, large, foamy macrophages. Levels of CXCL1/KC, CXCL5/LPS-induced CXC chemokine, granulocyte colony-stimulating factor, and VEGF in bronchoalveolar (BAL) fluid from chlorine-exposed mice showed steadily increasing trends over time. BAL protein levels were increased on day 4 and remained elevated out to day 28. The number of bacteria cultured from lungs of chlorine-exposed mice 4 wk after exposure was not increased compared with sham-exposed mice, indicating that the observed pneumonitis was not driven by bacterial infection of the lung. The results indicate that acute chlorine exposure may cause chronic abnormalities in the lungs despite rapid repair of injured epithelium. Copyright © 2015 the American Physiological Society.

40 CFR 141.132 - Monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... discretion. (2) Chlorite. Community and nontransient noncommunity water systems using chlorine dioxide, for... samples. (ii) Reduced monitoring. Monitoring may not be reduced. (2) Chlorine dioxide—(i) Routine... three chlorine dioxide distribution system samples. If chlorine dioxide or chloramines are used to...

BOOSTER CHLORINATION FOR MANAGING DISINFECTANT RESIDUALS

EPA Science Inventory

Booster chlorination is an approach to residual maintenance in which chlorine is applied at strategic locations within the distribution system. Situations in which booster chlorination may be most effective for maintaining a residual are explained informally in the context of a ...

DRINKING WATER DISINFECTION BY-PRODUCTS: WHAT IS KNOWN

EPA Science Inventory

Chlorine, ozone, chlorine dioxide, and chloramine are currently the major disinfectants being used to disinfect drinking water. Although the alternative disinfectants (ozone, chlorine dioxide, and chloramine) are increasing in popularity in the United States, chlorine is still us...

Naval Research Reviews, Volume 32, Number 4

DTIC Science & Technology

1980-01-01

iron while (e.g., carbon, chlorine, phosphorous, sulfur, zinc other areas are still covered by an oxide . An XPS and boron). An example of the chemical...picture. Metallic bearing components, for ex- major impact on tribology. The first is the develop- ample, usually have complex oxide films on their...the composition or thickncs. IThe optical image is m,.chanisms responsible for ion beam degradation of rotated slightly withrespecttoelectronimages

Altered UV absorbance and cytotoxicity of chlorinated sunscreen agents.

PubMed

Sherwood, Vaughn F; Kennedy, Steven; Zhang, Hualin; Purser, Gordon H; Sheaff, Robert J

2012-12-01

Sunscreens are widely utilized due to the adverse effects of ultraviolet (UV) radiation on human health. The safety of their active ingredients as well as that of any modified versions generated during use is thus of concern. Chlorine is used as a chemical disinfectant in swimming pools. Its reactivity suggests sunscreen components might be chlorinated, altering their absorptive and/or cytotoxic properties. To test this hypothesis, the UV-filters oxybenzone, dioxybenzone, and sulisobenzone were reacted with chlorinating agents and their UV spectra analyzed. In all cases, a decrease in UV absorbance was observed. Given that chlorinated compounds can be cytotoxic, the effect of modified UV-filters on cell viability was examined. Chlorinated oxybenzone and dioxybenzone caused significantly more cell death than unchlorinated controls. In contrast, chlorination of sulisobenzone actually reduced cytotoxicity of the parent compound. Exposing a commercially available sunscreen product to chlorine also resulted in decreased UV absorbance, loss of UV protection, and enhanced cytotoxicity. These observations show chlorination of sunscreen active ingredients can dramatically decrease UV absorption and generate derivatives with altered biological properties.

Point-of-use chlorination of turbid water: results from a field study in Tanzania.

PubMed

Mohamed, Hussein; Brown, Joe; Njee, Robert M; Clasen, Thomas; Malebo, Hamisi M; Mbuligwe, Steven

2015-06-01

Household-based chlorine disinfection is widely effective against waterborne bacteria and viruses, and may be among the most inexpensive and accessible options for household water treatment. The microbiological effectiveness of chlorine is limited, however, by turbidity. In Tanzania, there are no guidelines on water chlorination at household level, and limited data on whether dosing guidelines for higher turbidity waters are sufficient to produce potable water. This study was designed to assess the effectiveness of chlorination across a range of turbidities found in rural water sources, following local dosing guidelines that recommend a 'double dose' for water that is visibly turbid. We chlorinated water from 43 sources representing a range of turbidities using two locally available chlorine-based disinfectants: WaterGuard and Aquatabs. We determined free available chlorine at 30 min and 24 h contact time. Our data suggest that water chlorination with WaterGuard or Aquatabs can be effective using both single and double doses up to 20 nephelometric turbidity units (NTU), or using a double dose of Aquatabs up to 100 NTU, but neither was effective at turbidities greater than 100 NTU.

Integrated carbon and chlorine isotope modeling: applications to chlorinated aliphatic hydrocarbons dechlorination.

PubMed

Jin, Biao; Haderlein, Stefan B; Rolle, Massimo

2013-02-05

We propose a self-consistent method to predict the evolution of carbon and chlorine isotope ratios during degradation of chlorinated hydrocarbons. The method treats explicitly the cleavage of isotopically different C-Cl bonds and thus considers, simultaneously, combined carbon-chlorine isotopologues. To illustrate the proposed modeling approach we focus on the reductive dehalogenation of chlorinated ethenes. We compare our method with the currently available approach, in which carbon and chlorine isotopologues are treated separately. The new approach provides an accurate description of dual-isotope effects regardless of the extent of the isotope fractionation and physical characteristics of the experimental system. We successfully applied the new approach to published experimental results on dehalogenation of chlorinated ethenes both in well-mixed systems and in situations where mass-transfer limitations control the overall rate of biodegradation. The advantages of our self-consistent dual isotope modeling approach proved to be most evident when isotope fractionation factors of carbon and chlorine differed significantly and for systems with mass-transfer limitations, where both physical and (bio)chemical transformation processes affect the observed isotopic values.

Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers.

PubMed

Huang, Hai; Lin, Saisai; Zhang, Lin; Hou, Li'an

2017-03-22

Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N-H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.

Potential of isotope analysis (C, Cl) to identify dechlorination mechanisms

NASA Astrophysics Data System (ADS)

Cretnik, Stefan; Thoreson, Kristen; Bernstein, Anat; Ebert, Karin; Buchner, Daniel; Laskov, Christine; Haderlein, Stefan; Shouakar-Stash, Orfan; Kliegman, Sarah; McNeill, Kristopher; Elsner, Martin

2013-04-01

Chloroethenes are commonly used in industrial applications, and detected as carcinogenic contaminants in the environment. Their dehalogenation is of environmental importance in remediation processes. However, a detailed understanding frequently accounted problem is the accumulation of toxic degradation products such as cis-dichloroethylene (cis-DCE) at contaminated sites. Several studies have addressed the reductive dehalogenation reactions using biotic and abiotic model systems, but a crucial question in this context has remained open: Do environmental transformations occur by the same mechanism as in their corresponding in vitro model systems? The presented study shows the potential to close this research gap using the latest developments in compound specific chlorine isotope analysis, which make it possible to routinely measure chlorine isotope fractionation of chloroethenes in environmental samples and complex reaction mixtures.1,2 In particular, such chlorine isotope analysis enables the measurement of isotope fractionation for two elements (i.e., C and Cl) in chloroethenes. When isotope values of both elements are plotted against each other, different slopes reflect different underlying mechanisms and are remarkably insensitive towards masking. Our results suggest that different microbial strains (G. lovleyi strain SZ, D. hafniense Y51) and the isolated cofactor cobalamin employ similar mechanisms of reductive dechlorination of TCE. In contrast, evidence for a different mechanism was obtained with cobaloxime cautioning its use as a model for biodegradation. The study shows the potential of the dual isotope approach as a tool to directly compare transformation mechanisms of environmental scenarios, biotic transformations, and their putative chemical lab scale systems. Furthermore, it serves as an essential reference when using the dual isotope approach to assess the fate of chlorinated compounds in the environment.

Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes.

PubMed

Palau, Jordi; Marchesi, Massimo; Chambon, Julie C C; Aravena, Ramon; Canals, Àngels; Binning, Philip J; Bjerg, Poul L; Otero, Neus; Soler, Albert

2014-03-15

The use of compound specific multi-isotope approach (C and Cl) in the characterization of a chlorinated ethenes contaminated fractured aquifer allows the identification of several sources and contaminant plumes, as well as the occurrence of biodegradation and mixing processes. The study site is located in Spain with contamination resulting in groundwater concentrations of up to 50mg/L of trichloroethene (TCE), the most abundant chlorinated ethene, and 7 mg/L of tetrachloroethene (PCE). The potential sources of contamination including abandoned barrels, an underground tank, and a disposal lagoon, showed a wide range in δ(13)C values from -15.6 to -40.5‰ for TCE and from -18.5 to -32.4‰ for PCE, allowing the use of isotope fingerprinting for tracing of the origin and migration of these contaminants in the aquifer. In contrast, there is no difference between the δ(37)Cl values for TCE in the contaminant sources, ranging from +0.53 to +0.66‰. Variations of δ(37)Cl and δ(13)C in the different contaminant plumes were used to investigate the role of biodegradation in groundwater. Moreover, the isotopic data were incorporated into a reactive transport model for determination of whether the isotope pattern observed downstream from the tank's source could be explained by the simultaneous effect of mixing and biodegradation. The results demonstrate that a multi-isotope approach is a valuable tool for characterization of complex sites such as fractured bedrock aquifer contaminated by multiple sources, providing important information which can be used by consultants and site managers to prioritize and design more successful remediation strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

IDENTIFICATION OF CHLORINE DIOXIDE AND CHLORAMINE DRINKING WATER DISINFECTION BY-PRODUCTS

EPA Science Inventory

Due to concern over the potential adverse health effects of trihalomethanes (THMs) and other chlorinated by-products in chlorinated drinking water, alternative disinfection methods are being explored. Chlorine dioxide and chloramine are two popular alternative disinfectants, with...

The effect of pH and chloride concentration on the stability and antimicrobial activity of chlorine-based sanitizers.

PubMed

Waters, Brian W; Hung, Yen-Con

2014-04-01

Chlorinated water and electrolyzed oxidizing (EO) water solutions were made to compare the free chlorine stability and microbicidal efficacy of chlorine-containing solutions with different properties. Reduction of Escherichia coli O157:H7 was greatest in fresh samples (approximately 9.0 log CFU/mL reduction). Chlorine loss in "aged" samples (samples left in open bottles) was greatest (approximately 40 mg/L free chlorine loss in 24 h) in low pH (approximately 2.5) and high chloride (Cl(-) ) concentrations (greater than 150 mg/L). Reduction of E. coli O157:H7 was also negatively impacted (<1.0 log CFU/mL reduction) in aged samples with a low pH and high Cl(-) . Higher pH values (approximately 6.0) did not appear to have a significant effect on free chlorine loss or numbers of surviving microbial cells when fresh and aged samples were compared. This study found chloride levels in the chlorinated and EO water solutions had a reduced effect on both free chlorine stability and its microbicidal efficacy in the low pH solutions. Greater concentrations of chloride in pH 2.5 samples resulted in decreased free chlorine stability and lower microbicidal efficacy. © 2014 Institute of Food Technologists®

Intracellular distribution and stability of a luminescent rhenium(I) tricarbonyl tetrazolato complex using epifluorescence microscopy in conjunction with X-ray fluorescence imaging

DOE PAGES

Wedding, Jason L.; Harris, Hugh H.; Bader, Christie A.; ...

2016-11-23

Optical fluorescence microscopy was used in conjunction with X-ray fluorescence microscopy to monitor the stability and intracellular distribution of the luminescent rhenium(I) complex fac-[Re(CO) 3(phen)L], where phen = 1,10-phenathroline and L = 5-(4-iodophenyl)tetrazolato, in 22Rv1 cells. The rhenium complex showed no signs of ancillary ligand dissociation, a conclusion based on data obtained via X-ray fluorescence imaging aligning iodine and rhenium distributions. A diffuse reticular localisation was detected for the complex, in the nuclear/perinuclear region of cells, by either optical or X-ray fluorescence techniques. Furthermore, X-ray fluorescence also showed that the Re-I complex disrupted the homeostasis of some biologically relevant elements,more » such as chlorine, potassium and zinc.« less

Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

PubMed

Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

2017-12-01

Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Chlorine levels and species in fine and size resolved atmospheric particles by X-ray absorption near-edge structure spectroscopy analysis in Beijing, China.

PubMed

Ouyang, Jie; Yang, Guo-Sheng; Ma, Ling-Ling; Luo, Min; Zheng, Lei; Huo, Qing; Zhao, Yi-Dong; Hu, Tian-Dou; Cai, Zhen-Feng; Xu, Dian-Dou

2018-04-01

An understanding of the species of chlorine is crucial in the metropolis-Beijing, which is suffering serious haze pollution with high frequency. Particulate Matters (PMs) with five different sizes were collected in Beijing from July 2009 to March 2016, and characterized non-destructively by X-ray absorption near edge structure spectroscopy. PM <0.2 , PM 0.2-0.5 and PM >2.5 contributed for the major PMs mass in spring and summer, PM 0.5-1.0 and PM 1.0-2.5 contributed for the major PMs mass in autumn and winter. The concentrations of the three chlorine species were in the order of inorganic chlorine (Cl inorg ) > aliphatic chlorine (Cl ali ) > aromatic chlorine (Cl aro ), indicating that Cl inorg constituted the primary chlorine fraction and less toxic Cl ali constituted the primary total organic chlorine (Cl ali  + Cl aro , abbreviated as Cl org ) in the PMs in Beijing. In addition, these three chlorine species exhibited identical seasonal variation in PM 2.5 : winter > autumn > spring > summer. Wet precipitation is an important factor to result in the lower mass concentrations of these three chlorine species in summer. The temporal variations of both size resolved PM mass concentrations and chlorine species concentrations suggested that the air pollution prevention and control in Beijing has just won initial success. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Formation mechanism and chemical safety of nonintentional chemical substances present in chlorinated drinking water and wastewater].

PubMed

Onodera, Sukeo

2010-09-01

This paper reviews the formation mechanism and chemical safety of nonintentional chemical substances (NICS) present in chlorine-treated water containing organic contaminants. Undesirable compounds, i.e., NICS, may be formed under certain conditions when chlorine reacts with organic matter. The rate and extent of chlorine consumption with organics are strongly dependent on their chemical structures, particularly whether double bonds or sulfur and nitrogen atoms occur in the molecules. Organothiophosphorus pesticides (P=S type) are easily oxidized to their phosphorus compounds (P=O type) in chlorinated water containing HOCl as little as 0.5 mg/l, resulting in an increase in cholinesterase-inhibitory activity. Chlorination of phenols in water also produces a series of highly chlorinated compounds, including chlorophenols, chloroquinones, chlorinated carboxylic acids, and polychlorinated phenoxyphenols (PCPPs). In some of these chloroquinones, 2,6-dichloroalkylsemiquinones exhibit a strong mutagenic response as do positive controls used in the Ames test. 2-phenoxyphenols in these PCPPs are particularly interesting, as they are present in the chlorine-treated phenol solution and they are also precursors (predioxins) of the highly toxic chlorinated dioxins. Polynuclear aromatic hydrocarbons (PAHs) were found to undergo chemical changes due to hypochlorite reactions to give chloro-substituted PAHs, oxygenated (quinones) and hydroxylated (phenols) compounds, but they exhibit a lower mutagenic response. In addition, field work was performed in river water and drinking water to obtain information on chemical distribution and their safety, and the results are compared with those obtained in the model chlorination experiments.

THE EFFECT OF CHLORINE EMISSIONS ON TROPOSPHERIC OZONE IN THE UNITED STATES

EPA Science Inventory

The effect of chlorine emissions on atmospheric ozone in the continental United States was evaluated. Atmospheric chlorine chemistry was combined with the carbon bond mechanism and incorporated into the Community Multiscale Air Quality model. Sources of chlorine included anthrop...

Long-Term Effects of Residual Chlorine on Pseudomonas aeruginosa in Simulated Drinking Water Fed With Low AOC Medium

PubMed Central

Mao, Guannan; Song, Yuhao; Bartlam, Mark; Wang, Yingying

2018-01-01

Residual chlorine is often required to remain present in public drinking water supplies during distribution to ensure water quality. It is essential to understand how bacteria respond to long-term chlorine exposure, especially with the presence of assimilable organic carbon (AOC). This study aimed to investigate the effects of chlorination on Pseudomonas aeruginosa in low AOC medium by both conventional plating and culture-independent methods including flow cytometry (FCM) and quantitative PCR (qPCR). In a simulated chlorinated system using a bioreactor, membrane damage and DNA damage were measured by FCM fluorescence fingerprint. The results indicated membrane permeability occurred prior to DNA damage in response to chlorination. A regrowth of P. aeruginosa was observed when the free chlorine concentration was below 0.3 mg/L. The bacterial response to long-term exposure to a constant low level of free chlorine (0.3 mg/L) was subsequently studied in detail. Both FCM and qPCR data showed a substantial reduction during initial exposure (0–16 h), followed by a plateau where the cell concentration remained stable (16–76 h), until finally all bacteria were inactivated with subsequent continuous chlorine exposure (76–124 h). The results showed three-stage inactivation kinetics for P. aeruginosa at a low chlorine level with extended exposure time: an initial fast inactivation stage, a relatively stable middle stage, and a final stage with a slower rate than the initial stage. A series of antibiotic resistance tests suggested long-term exposure to low chlorine level led to the selection of antibiotic-resistant P. aeruginosa. The combined results suggest that depletion of residual chlorine in low AOC medium systems could reactivate P. aeruginosa, leading to a possible threat to drinking water safety. PMID:29774019

Characteristics of salt taste and free chlorine or chloramine in drinking water.

PubMed

Wiesenthal, K E; McGuire, M J; Suffet, I H

2007-01-01

Salty taste with or without chlorine or chloramine flavour is one of the major consumer complaints to water utilities. The flavour profile analysis (FPA) taste panel method determined the average taste threshold concentration for salt (NaCl) in Milli-Q water to be 640 +/- 3 mg/L at pH 8. Chlorine and chloramine disinfectants have no antagonistic or synergistic effects on the taste of NaCl, salt, in Milli-Q water. The flavour threshold concentrations for chlorine or chloramine in Milli-Q water alone or in the presence of NaCl could not be estimated by the Weber-Fechner curves due to the chlorine or chloramine flavour outliers in the 0.2-0.8 mg/L concentration range. Apparently, NaCl is not equilibrated with the concentration of ions in the saliva in the mouth and the concentration of free chlorine or chloramines cannot be tasted correctly. Therefore, dechlorinated tap water may be the best background water to use for a particular drinking water evaluation of chlorine and chloramine thresholds. Laboratory FPA studies of free chlorine found that a 67% dilution of Central Arizona Project (CAP) (Tucson, AZ) water with Milli-O water was required to reduce the free chlorine flavour to a threshold value instead of a theoretical value of 80% (Krasner and Barrett, 1980). No synergistic effect was found for chlorine flavour on the dilution of CAP water with Milli-Q water. When Central Avra Valley (AVRA) groundwater was used for the dilution of CAP water, a synergistic effect of the TDS present was observed for the chlorine flavour. Apparently, the actual mineral content of drinking water, and not just NaCl in Milli-Q water, is needed for comparative flavour tests for chlorine and chloramines.

Shifts of live bacterial community in secondary effluent by chlorine disinfection revealed by Miseq high-throughput sequencing combined with propidium monoazide treatment.

PubMed

Pang, Yu-Chen; Xi, Jin-Ying; Xu, Yang; Huo, Zheng-Yang; Hu, Hong-Ying

2016-07-01

Chlorine disinfection is a commonly used disinfection process in wastewater treatment, but its effects on the indigenous bacterial community in treated wastewater have not been fully elucidated. In this study, secondary effluent samples collected in four wastewater treatment plants (WWTPs) were selected for chlorine disinfection. Shifts in the bacterial community compositions in secondary effluent samples upon chlorine disinfection, both immediately and after 24 h of storage, were investigated using Illumina MiSeq sequencing combined with propidium monoazide (PMA) treatment. The results showed that the phylum Proteobacteria was sensitive to chlorine, with the relative proportions of Proteobacteria decreased from 39.2 to 75.9 % in secondary effluent samples to 7.5 to 62.2 % immediately after chlorine disinfection. The phylogenetic analysis indicated that the most dominant genera belonging to Proteobacteria were sensitive to chlorine. In contrast, the phyla Firmicutes and Planctomycetes showed a certain resistance to chlorine, with their relative proportions increasing from 5.1 to 23.1 % and 0.8 to 9.3 % to 11.3 to 44.6 % and 1.5 to 13.3 %, respectively. Most dominant genera belonging to Firmicutes showed resistance to chlorine. A significant reduction in the richness and diversity of the bacterial community was observed after 24 h of storage of chlorinated secondary effluent. During the 24-h storage process, the relative proportions of most dominant phyla shifted in reverse from the changes induced by chlorine disinfection. Overall, chlorine disinfection not only changes the bacterial community compositions immediately after the disinfection process but also exerts further impacts over a longer period (24 h).

Removal of endocrine disruptors and non-steroidal anti-inflammatory drugs through wastewater chlorination: the effect of pH, total suspended solids and humic acids and identification of degradation by-products.

PubMed

Noutsopoulos, Constantinos; Koumaki, Elena; Mamais, Daniel; Nika, Maria-Christina; Bletsou, Anna A; Thomaidis, Nikolaos S

2015-01-01

Endocrine disrupting chemicals (EDCs) and non-steroidal anti-inflammatory drugs (NSAIDs) are two groups of emerging pollutants the significance of which rests on their persistent detection in the aquatic environment and their possible adverse effects. Wastewater treatment plants are one of the major ways for transporting such chemicals in the aquatic environment. Chlorination is usually the last stage of treatment before wastewater being disposed to the aquatic environment. This work focuses on the evaluation of the effect of chlorine dose and specific wastewater characteristics (pH, total suspended solids and humic acids) on the removal of target EDCs and NSAIDs through chlorination. Another objective of this study is the identification of chlorination by-products of specific EDCs and NSAIDs and their dependence on contact time. Based on the results it is concluded that the effect of chlorine dose and humic acids concentration on the degradation of target compounds during chlorination is minimal. On the contrary, pH is a critical parameter which highly affects process performance. Moreover, it is concluded that not only the free available chlorine species, but also the properties of EDCs and NSAIDs under different pH conditions can affect chlorination process performance. The effect of TSS on the degradation of the target compounds during chlorination is more profound for chemicals with high Kow values and therefore higher affinity to partition to the particulate phase (i.e. nonylphenols, triclosan). Several degradation by-products were identified through chlorination of nonylphenol, bisphenol A and diclofenac. The dependence of these by-products on chlorination contact time is also demonstrated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chlorine residuals and haloacetic acid reduction in rapid sand filtration.

PubMed

Chuang, Yi-Hsueh; Wang, Gen-Shuch; Tung, Hsin-hsin

2011-11-01

It is quite rare to find biodegradation in rapid sand filtration for drinking water treatment. This might be due to frequent backwashes and low substrate levels. High chlorine concentrations may inhibit biofilm development, especially for plants with pre-chlorination. However, in tropical or subtropical regions, bioactivity on the sand surface may be quite significant due to high biofilm development--a result of year-round high temperature. The objective of this study is to explore the correlation between biodegradation and chlorine concentration in rapid sand filters, especially for the water treatment plants that practise pre-chlorination. In this study, haloacetic acid (HAA) biodegradation was found in conventional rapid sand filters practising pre-chlorination. Laboratory column studies and field investigations were conducted to explore the association between the biodegradation of HAAs and chlorine concentrations. The results showed that chlorine residual was an important factor that alters bioactivity development. A model based on filter influent and effluent chlorine was developed for determining threshold chlorine for biodegradation. From the model, a temperature independent chlorine concentration threshold (Cl(threshold)) for biodegradation was estimated at 0.46-0.5mgL(-1). The results imply that conventional filters with adequate control could be conducive to bioactivity, resulting in lower HAA concentrations. Optimizing biodegradable disinfection by-product removal in conventional rapid sand filter could be achieved with minor variation and a lower-than-Cl(threshold) influent chlorine concentration. Bacteria isolation was also carried out, successfully identifying several HAA degraders. These degraders are very commonly seen in drinking water systems and can be speculated as the main contributor of HAA loss. Copyright © 2011 Elsevier Ltd. All rights reserved.

Chlorine stabilizer T-128 enhances efficacy of chlorine against cross-contamination by E. coli O157:H7 and Salmonella in fresh-cut lettuce processing.

PubMed

Nou, Xiangwu; Luo, Yaguang; Hollar, LaVonda; Yang, Yang; Feng, Hao; Millner, Patricia; Shelton, Daniel

2011-04-01

During fresh-cut produce processing, organic materials released from cut tissues can rapidly react with free chlorine in the wash solution, leading to the potential survival of foodborne bacterial pathogens, and cross-contamination when the free chlorine is depleted. A reported chlorine stabilizer, T-128, has been developed to address this problem. In this study, we evaluated the ability of T-128 to stabilize free chlorine in wash solutions in the presence of high organic loads generated by the addition of lettuce extract or soil. Under conditions used in this study, T-128 significantly (P<0.001) decreased the rate of free chlorine depletion at the presence of soil. T-128 also slightly decreased the rate of free chlorine depletion caused by the addition of lettuce extract in wash solution. Application of T-128 significantly reduced the survival of bacterial pathogens in wash solutions with high organic loads and significantly reduced the potential of cross-contamination, when contaminated and uncontaminated produce were washed together. However, T-128 did not enhance the efficacy of chlorinated wash solutions for microbial reduction on contaminated iceberg lettuce. Evaluation of several produce quality parameters, including overall visual appearance, package headspace O2 and CO2 composition, and lettuce electrolyte leakage, during 15 d of storage indicated that iceberg lettuce quality and shelf life were not negatively impacted by washing fresh-cut lettuce in chlorine solutions containing 0.1% T-128.   Reported chlorine stabilizer is shown to enhance chlorine efficacy against potential bacterial cross-contamination in the presence of high organic loads without compromising product quality and shelf life.

In Situ Treatment of Chlorinated Ethene-Contaminated Groundwater Using horizontal Flow Treatment Wells.

DTIC Science & Technology

2000-03-01

groundwater, Environmental Science and Technology, 30 (12): 536A-539A, 1996. Arnold, W. A. and A. L. Roberts, Pathways of chlorinated ethylene and...chlorinated acetylene reaction with Zn(0), Environmental Science and Technology, 32 (19): 3017-3025, 1998. Arnold, W. A. and A. L. Roberts, Pathways and...kinetics of chlorinated ethylene and chlorinated acetylene reaction with Fe(0) particles, Environmental Science and Technology, in press, 2000

The Chlorination Quandary

ERIC Educational Resources Information Center

Josephson, Julian

1978-01-01

Current use of chlorination technology to disinfect water supplies can cause the production of undesirable products, among them chloroform and chlorobenzene. Alternatives to this methodology include the use of ozone, chlorine dioxide, and bromine chloride in place of chlorine. Presently, the methods are feasible in developed countries only. (MA)

CHLORINE DECAY AND BIOFILM STUDIES IN A PILOT SCALE DRINKING WATER DISTRIBUTION DEAD END PIPE SYSTEM

EPA Science Inventory

Chlorine decay experiments using a pilot-scale water distribution dead end pipe system were conducted to define relationships between chlorine decay and environmental factors. These included flow rate, biomass concentration and biofilm density, and initial chlorine concentrations...

Determination of Residual Chlorine and Turbidity in Drinking Water. Instructor's Manual.

ERIC Educational Resources Information Center

Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

This instructor's guide presents analytical methods for residual chlorine and turbidity. Topics include sample handling, permissable concentration levels, substitution of residual chlorine for bacteriological work, public notification, and the required analytical techniques to determine residual chlorine and turbidity. This publication is intended…

IDENTIFICATION OF CHLORINE DIOXIDE DRINKING WATER DISINFECTION BY-PRODUCTS FORMED AT HIGH BROMIDE LEVELS

EPA Science Inventory

Due to concern over the potential adverse health effects of trihalomethanes (THMs), haloacetic acids, and other chlorinated by-products in chlorinated drinking water, alternative disinfection methods are being explored. Chlorine dioxide is a popular alternative, with over 500 dri...

Chlorine partitioning in the lowermost Arctic vortex during the cold winter 2015/2016

NASA Astrophysics Data System (ADS)

Marsing, Andreas; Jurkat, Tina; Voigt, Christiane; Kaufmann, Stefan; Schlage, Romy; Engel, Andreas; Hoor, Peter; Krause, Jens

2017-04-01

Reactive chlorine compounds in the polar winter stratosphere are central to the formation of the Arctic ozone hole. To study the distribution and partitioning of active chlorine and reservoir species in the lower stratosphere, we performed in-situ measurements of HCl and ClONO2 with the mass spectrometer AIMS during the POLSTRACC aircraft campaign in the Arctic winter 2015/2016 between 320 K and 410 K. In addition to chlorine reservoir gases, in-situ measurements of chemically stable tracers provide means to identify vortex air masses and to infer total inorganic chlorine (Cly). The distribution of chlorine and the degree of activation during the winter, as well as the reformation of the reservoir species at the end of the polar winter vary with altitude and potential temperature. Using trajectory calculations, we demonstrate transport pathways that distribute high amounts of previously activated chlorine into the lowermost stratosphere. Here, active chlorine may have a large oxidation capacity with respect to climate relevant trace gases.

Formation of N-nitrosodimethylamine (NDMA) from dimethylamine during chlorination.

PubMed

Mitch, William A; Sedlak, David L

2002-02-15

Chlorine disinfection of secondary wastewater effluent and drinking water can result in the production of the potent carcinogen N-nitrosodimethylamine (NDMA) at concentrations of approximately 100 and 10 parts per trillion (ng/L), respectively. Laboratory experiments with potential NDMA precursors indicate that NDMA formation can form during the chlorination of dimethylamine and other secondary amines. The formation of NDMA during chlorination may involve the slow formation of 1,1-dimethylhydrazine by the reaction of monochloramine and dimethylamine followed by its rapid oxidation to NDMA and other products including dimethylcyanamide and dimethylformamide. Other pathways also lead to NDMA formation during chlorination such as the reaction of sodium hypochlorite with dimethylamine. However, the rate of NDMA formation is approximately an order of magnitude slower than that observed when monochloramine reacts with dimethylamine. The reaction exhibits a strong pH dependence due to competing reactions. It may be possible to reduce NDMA formation during chlorination by removing ammonia prior to chlorination, by breakpoint chlorination, or by avoidance of the use of monochloramine for drinking water disinfection.

Photodynamic tissue adhesion with chlorin(e6) protein conjugates.

PubMed

Khadem, J; Veloso, A A; Tolentino, F; Hasan, T; Hamblin, M R

1999-12-01

To test the hypothesis that a photodynamic laser-activated tissue solder would perform better in sealing scleral incisions when the photosensitizer was covalently linked to the protein than when it was noncovalently mixed. Conjugates and mixtures were prepared between the photosensitizer chlorin(e6) and various proteins (albumin, fibrinogen, and gelatin) in different ratios and used to weld penetrating scleral incisions made in human cadaveric eyes. A blue-green (488-514 nm) argon laser activated the adhesive, and the strength of the closure was measured by increasing the intraocular pressure until the wound showed leakage. Both covalent conjugates and noncovalent mixtures showed a light dose-dependent increase in leaking pressure. A preparation of albumin chlorin(e6) conjugate with additional albumin added (2.5 protein to chlorin(e6) molar ratio) showed significantly higher weld strength than other protein conjugates and mixtures. This is the first report of dye-protein conjugates as tissue solders. These conjugates may have applications in ophthalmology.

Prospects of in vivo singlet oxygen luminescence monitoring: Kinetics at different locations on living mice.

PubMed

Pfitzner, Michael; Schlothauer, Jan C; Bastien, Estelle; Hackbarth, Steffen; Bezdetnaya, Lina; Lassalle, Henri-Pierre; Röder, Beate

2016-06-01

Singlet oxygen observation is considered a valuable tool to assess and optimize PDT treatment. In complex systems, such as tumors in vivo, only the direct, time-resolved singlet oxygen luminescence detection can give reliable information about generation and interaction of singlet oxygen. Up to now, evaluation of kinetics was not possible due to insufficient signal-to-noise ratio. Here we present high signal-to-noise ratio singlet oxygen luminescence kinetics obtained in mouse tumor model under PDT relevant conditions. A highly optimized system based on a custom made laser diode excitation source and a high aperture multi-furcated fiber, utilizing a photomultiplier tube with a multi photon counting device was used. Luminescence kinetics with unsurpassed signal-to-noise ratio were gained from tumor bearing nude mice in vivo upon topic application, subcutaneous injection as well as intravenous injection of different photosensitizers (chlorin e6 and dendrimer formulations of chlorin e6). Singlet oxygen kinetics in appropriate model systems are discussed to facilitate the interpretation of complex kinetics obtained from in vivo tumor tissue. This is the first study addressing the complexity of singlet oxygen luminescence kinetics in tumor tissue. At present, further investigations are needed to fully explain the processes involved. Nevertheless, the high signal-to-noise ratio proves the applicability of direct time-resolved singlet oxygen luminescence detection as a prospective tool for monitoring photodynamic therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Crystal structures of human cholinesterases in complex with huprine W and tacrine: elements of specificity for anti-Alzheimer's drugs targeting acetyl- and butyryl-cholinesterase.

PubMed

Nachon, Florian; Carletti, Eugénie; Ronco, Cyril; Trovaslet, Marie; Nicolet, Yvain; Jean, Ludovic; Renard, Pierre-Yves

2013-08-01

The multifunctional nature of Alzheimer's disease calls for MTDLs (multitarget-directed ligands) to act on different components of the pathology, like the cholinergic dysfunction and amyloid aggregation. Such MTDLs are usually on the basis of cholinesterase inhibitors (e.g. tacrine or huprine) coupled with another active molecule aimed at a different target. To aid in the design of these MTDLs, we report the crystal structures of hAChE (human acetylcholinesterase) in complex with FAS-2 (fasciculin 2) and a hydroxylated derivative of huprine (huprine W), and of hBChE (human butyrylcholinesterase) in complex with tacrine. Huprine W in hAChE and tacrine in hBChE reside in strikingly similar positions highlighting the conservation of key interactions, namely, π-π/cation-π interactions with Trp86 (Trp82), and hydrogen bonding with the main chain carbonyl of the catalytic histidine residue. Huprine W forms additional interactions with hAChE, which explains its superior affinity: the isoquinoline moiety is associated with a group of aromatic residues (Tyr337, Phe338 and Phe295 not present in hBChE) in addition to Trp86; the hydroxyl group is hydrogen bonded to both the catalytic serine residue and residues in the oxyanion hole; and the chlorine substituent is nested in a hydrophobic pocket interacting strongly with Trp439. There is no pocket in hBChE that is able to accommodate the chlorine substituent.

Stratospheric chlorine injection by volcanic eruptions - HCl scavenging and implications for ozone

NASA Technical Reports Server (NTRS)

Tabazadeh, A.; Turco, R. P.

1993-01-01

Because the output of volatile chlorine during a major volcanic event can greatly exceed the annual anthropogenic emissions of chlorine to the atmosphere, the fate of volcanic chlorine must be known. Although numerous observations have shown that volcanoes do not significantly contribute to the stratospheric chlorine burden, no quantitative explanation has been published. Hydrogen chloride (HCl) scavenging processes during the early phases of a volcanic eruption are discussed. A plume dynamics and thermodynamics model is used to show that HCl removal in condensed supercooled water can reduce HCl vapor concentrations by up to four orders of magnitude, preventing substantial stratospheric chlorine injection.

Selective synthesis and characterization of chlorins as sensitizers for photodynamic therapy

NASA Astrophysics Data System (ADS)

Montforts, Franz-Peter; Kusch, Dirk; Hoper, Frank; Braun, Stefan; Gerlach, Benjamin; Brauer, Hans-Dieter; Schermann, Guido; Moser, Joerg G.

1996-04-01

Chlorin type sensitizers have ideal photophysical properties for an application in PDT. The basic chlorin framework of these sensitizers has to be modified by attachment of lipophilic and hydrophilic residues to achieve a good cell uptake and tumor enrichment. In the present study we describe the selective synthesis of amphiphilic chlorins starting from the readily accessible red blood pigment heme. The photophysical properties of the well defined synthetic chlorins are characterized by photophysical investigations. The kinetic of cell uptake, the localization in the cell and the photodynamic behavior of the amphiphilic sensitizers are demonstrated by incubation of A 375 cancer cell lines with structurally different chlorins.

Degradation of acrylamide by the UV/chlorine advanced oxidation process.

PubMed

Gao, Ze-Chen; Lin, Yi-Li; Xu, Bin; Pan, Yang; Xia, Sheng-Ji; Gao, Nai-Yun; Zhang, Tian-Yang; Chen, Ming

2017-11-01

The degradation of acrylamide (AA) during UV/chlorine advanced oxidation process (AOP) was investigated in this study. The degradation of AA was negligible during UV irradiation alone. However, AA could be effectively degraded and mineralized during UV/chlorination due to the generation of hydroxyl radicals (OH). The degradation kinetics of AA during UV/chlorination fitted the pseudo-first order kinetics with the rate constant between AA and OH radicals being determined as 2.11 × 10 9  M -1  s -1 . The degradation rate and mineralization of AA during UV/chlorination were significantly promoted at acidic conditions as well as increasing chlorine dosage. The volatile degradation products of AA during UV/chlorination were identified using gas chromatography-mass spectrometry and the degradation pathways were then proposed accordingly. The formation of disinfection by-products (DBPs) in Milli-Q water and tap water during UV/chlorination of AA was also investigated. The DBPs included chloroform, dichloroacetonitrile, trichloroacetonitrile, 2,2-dichloroacetamide and 2,2,2-trichloroacetamide. Furthermore, the variations of AA degradation during UV/chlorination in different real water samples were evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Separation of chlorinated diastereomers of decarboxy-betacyanins in myeloperoxidase catalyzed chlorinated Beta vulgaris L. extract.

PubMed

Wybraniec, Sławomir; Starzak, Karolina; Szneler, Edward; Pietrzkowski, Zbigniew

2016-11-15

A comparative chromatographic evaluation of chlorinated decarboxylated betanins and betanidins generated under activity of hypochlorous acid exerted upon these highly antioxidative potent decarboxylated pigments derived from natural sources was performed by LC-DAD-ESI-MS/MS. Comparison of the chromatographic profiles of the chlorinated pigments revealed two different directions of retention changes in relation to the corresponding substrates. Chlorination of all betacyanins that are decarboxylated at carbon C-17 results in an increase of their retention times. In contrast, all other pigments (the non-decarboxylated betacyanins as well as 2-decarboxy- and 15-decarboxy-derivatives) exhibit lower retention after chlorination. During further chromatographic experiments based upon chemical transformation of the related pigments (decarboxylation and deglucosylation), the compounds' structures were confirmed. The elaborated method for determination of chlorinated pigments enabled analysis of a chlorinated red beet root extract that was submitted to the MPO/H 2 O 2 /Cl - system acting under inflammation-like conditions (pH 5). This indicates a promising possibility for measurement of these chlorinated pigments as indicators of specific inflammatory states wherein betacyanins and decarboxylated betacyanins act as hypochlorite scavengers. Copyright © 2016 Elsevier B.V. All rights reserved.

Organic matter chlorination rates in different boreal soils: the role of soil organic matter content.

PubMed

Gustavsson, Malin; Karlsson, Susanne; Oberg, Gunilla; Sandén, Per; Svensson, Teresia; Valinia, Salar; Thiry, Yves; Bastviken, David

2012-02-07

Transformation of chloride (Cl(-)) to organic chlorine (Cl(org)) occurs naturally in soil but it is poorly understood how and why transformation rates vary among environments. There are still few measurements of chlorination rates in soils, even though formation of Cl(org) has been known for two decades. In the present study, we compare organic matter (OM) chlorination rates, measured by (36)Cl tracer experiments, in soils from eleven different locations (coniferous forest soils, pasture soils and agricultural soils) and discuss how various environmental factors effect chlorination. Chlorination rates were highest in the forest soils and strong correlations were seen with environmental variables such as soil OM content and Cl(-) concentration. Data presented support the hypothesis that OM levels give the framework for the soil chlorine cycling and that chlorination in more organic soils over time leads to a larger Cl(org) pool and in turn to a high internal supply of Cl(-) upon dechlorination. This provides unexpected indications that pore water Cl(-) levels may be controlled by supply from dechlorination processes and can explain why soil Cl(-) locally can be more closely related to soil OM content and the amount organically bound chlorine than to Cl(-) deposition.

Assessment of residual active chlorine in sodium hypochlorite solutions after dissolution of porcine incisor pulpal tissue.

PubMed

Clarkson, R M; Smith, T K; Kidd, B A; Evans, G E; Moule, A J

2013-12-01

In previous studies, surfactant-containing Hypochlor brands of sodium hypochlorite showed better tissue solubilizing abilities than Milton; differences not explained by original active chlorine content or presence of surfactant. It was postulated that exhaustion of active chlorine content could explain differences. This study aimed to assess whether Milton's poorer performance was due to exhaustion of active chlorine. Parallel experiments assessed the influence of titration methods, and the presence of chlorates, on active chlorine measurements. Time required to dissolve one or groups of 10 samples of porcine incisor pulp samples in Milton was determined. Residual active chlorine was assessed by thermometric titration. Iodometric and thermometric titration was carried out on samples of Milton. Chlorate content was also measured. Dissolution of single and 10 pulp samples caused a mean loss of 1% and 3% respectively of active chlorine, not being proportional to tissue dissolved. Thermometric ammonium ion titration resulted in 10% lower values than iodometric titration. Chlorate accounted for much of this difference. Depletion of active chlorine is not the reason for differences in tissue dissolving capabilities of Milton. Thermometric ammonium ion titration gives more accurate measurement of active chlorine content than iodometric titration. © 2013 Australian Dental Association.

A carbon nanotube based resettable sensor for measuring free chlorine in drinking water

NASA Astrophysics Data System (ADS)

Hsu, Leo H. H.; Hoque, Enamul; Kruse, Peter; Ravi Selvaganapathy, P.

2015-02-01

Free chlorine from dissolved chlorine gas is widely used as a disinfectant for drinking water. The residual chlorine concentration has to be continuously monitored and accurately controlled in a certain range around 0.5-2 mg/l to ensure drinking water safety and quality. However, simple, reliable, and reagent free monitoring devices are currently not available. Here, we present a free chlorine sensor that uses oxidation of a phenyl-capped aniline tetramer (PCAT) to dope single wall carbon nanotubes (SWCNTs) and to change their resistance. The oxidation of PCAT by chlorine switches the PCAT-SWCNT system into a low resistance (p-doped) state which can be detected by probing it with a small voltage. The change in resistance is found to be proportional to the log-scale concentration of the free chlorine in the sample. The p-doping of the PCAT-SWCNT film then can be electrochemically reversed by polarizing it cathodically. This sensor not only shows good sensing response in the whole concentration range of free chlorine in drinking water but is also able to be electrochemically reset back many times without the use of any reagents. This simple sensor is ideally suited for measuring free chlorine in drinking water continuously.

[Inactivation of the chlorine-resistant bacteria isolated from the drinking water distribution system].

PubMed

Chen, Yu-Qiao; Duan, Xiao-Di; Lu, Pin-Pin; Wang, Qian; Zhang, Xiao-Jian; Chen, Chao

2012-01-01

Inactivation experiments of seven strains of chlorine-resistant bacteria, isolated from a drinking water distribution system, were conducted with four kinds of disinfectants. All the bacteria showed high resistance to chlorine, especially for Mycobacterium mucogenicum. The CT value of 99.9% inactivation for M. mucogenicum, Sphingomonas sanguinis and Methylobacterium were 120 mg x (L x min)(-1), 7 mg x (L x min)(-1) and 4 mg x (L x min)(-1), respectively. The results of inactivation experiments showed that chlorine dioxide and potassium monopersulfate could inactive 5 lg of M. mucogenicum within 30 min, which showed significantly higher efficiency than free chlorine and monochloramine. Free chlorine was less effective because the disinfectant decayed very quickly. Chloramination needed higher concentration to meet the disinfection requirements. The verified dosage of disinfectants, which could effectively inactivate 99.9% of the highly chlorine-resistant M. mucogenicum within 1 h, were 3.0 mg/L monochloramine, 1.0 mg/L chlorine dioxide (as Cl2), and 1.0 mg/L potassium monopersulfate (as Cl2). It was suggested that the water treatment plants increase the concentration of monochloramine or apply chlorine dioxide intermittently to control the disinfectant-resistant bacteria.

Effects of chain length, chlorination degree, and structure on the octanol-water partition coefficients of polychlorinated n-alkanes.

PubMed

Hilger, Bettina; Fromme, Hermann; Völkel, Wolfgang; Coelhan, Mehmet

2011-04-01

Log octanol-water partition coefficients (log Kow) of 40 synthesized polychlorinated n-alkanes (PCAs) with different chlorination degrees were determined using reversed-phase high performance liquid chromatography (RP-HPLC). In addition, log Kow values of a technical mixture namely Cereclor 63L as well as 15 individual in house synthesized C10, C11, and C12 chloroalkanes with known chlorine positions were estimated. Based on these results, the effects of chain length, chlorination degree, and structure were explored. The estimated log Kow values ranged from 4.10 (polychlorinated n-decanes with 50.2% chlorine content) to 11.34 (polychlorinated n-octacosanes with 54.8% chlorine content) for PCAs and from 3.82 (1,2,5,6,9,10-hexachlorodecane) to 7.75 (1,1,1,3,9,11,11,11-octachlorododecane) for the individual chloroalkanes studied. The results showed that log Kow value was influenced linearly at a given chlorine content by chain length, while a polynominal effect was observed in dependence on the chlorination degree of an alkane chain. Chlorine substitution pattern influenced markedly the log Kow value of chloroalkanes.

The Influence of Nitrogen Oxides on Chlorine Chemistry in Barrow, Alaska

NASA Astrophysics Data System (ADS)

McNamara, S. M.; Raso, A. R. W.; Wang, S.; Thanekar, S.; Fuentes, J. D.; Shepson, P. B.; Pratt, K.

2016-12-01

Active chlorine chemistry in the springtime Arctic boundary layer impacts the fate of atmospheric pollutants and greenhouse gases. Recent field studies have reported high amounts of molecular chlorine (Cl2), up to 400 parts per trillion (ppt), as well as the presence of chlorinated hydrocarbon oxidation products. However, our knowledge of Arctic chlorine chemistry is limited by a paucity of observations. The presence of nitrogen oxides (NOx) may influence the chlorine chemistry in this region. Here, we report chemical ionization mass spectrometry measurements of Cl2, chlorine monoxide (ClO), nitryl chloride (ClNO2), and dinitrogen pentoxide (N2O5), and NOx measurements at Barrow, AK during March-May 2016. To our knowledge, these data represent the first observations of ClNO2 in the Arctic. While the main source of NOx in a pristine Arctic environment is irradiated snow surfaces, anthropogenic sources can significantly enhance local NOx concentrations. The role of NOx in the activation and temporal trends of the reactive chlorine species are examined using a 0-D photochemical model. The prevalence of chlorine chemistry under elevated nitrogen oxide conditions may have significant impacts on the atmospheric composition in an increasingly polluted Arctic.

Preliminary GRS Measurement of Chlorine Distribution on Surface of Mars

NASA Astrophysics Data System (ADS)

Keller, J. M.; Boynton, W. V.; Taylor, G. J.; Hamara, D.; Janes, D. M.; Kerry, K.

2003-12-01

Ongoing measurements with the Gamma Ray Spectrometer (GRS) aboard Mars Odyssey provide preliminary detection of chlorine at the surface of Mars. Summing all data since boom deployment and using a forward calculation model, we estimate values for chlorine concentration at 5° resolution. Rebinning this data and smoothing with a 15-degree-radius boxcar filter reveal regions of noticeable chlorine enrichment at scales larger than the original 5° resolution and allow for preliminary comparison with previous Mars datasets. Analyzing chlorine concentrations within 30 degrees of the equator, we find a negative correlation with thermal inertia (R2=0.55) and positive correlation with albedo (R2=0.52), indicating that chlorine is associated with fine, non-rock surface materials. Although possibly a smoothing artifact, the spatial correlation is more noticeable in the region covering Tharsis and Amazonis than around Arabia and Elysium. Additionally, a noticeable region of chlorine enrichment appears west of Tharsis Montes ( ˜0 to 20N, ˜110 to 150W) and chlorine concentration is estimated to vary in the equatorial region by over a factor of two. A simplified two-component model involving chlorine-poor rocks and a homogenous chlorine-rich fine material requires rock abundance to vary from zero to over 50%, a result inconsistent with previous measurements and models. In addition to variations in rock composition and distribution, substantial variations in chlorine content of various types of fine materials including dust, sand, and duricrust appear important in explaining this preliminary observation. Surprisingly, visual comparison of surface units mapped by Christensen and Moore (1992) does not show enrichment in chlorine associated with regions of indurated surfaces, where cementation has been proposed. Rather, Tharsis, a region of active deposition with proposed mantling of 0.1 to 2 meters of recent dust (Christensen 1986), shows the greatest chlorine signal. In light of suggested fine material formation mechanisms, this preliminary result is intriguing. Tentative models involving venting of chlorine from hydrothermal systems (Newsom 1999), enrichment of chlorine through volcanic aerosols (Settle 1979) or acid fog reactions (Banin et al 1997), and preferential deposition of a proposed salt component in Mars fines (Clark 1993), if more easily mobilized from the Martian duricrust, are viable. Finally, this preliminary measurement will be improved through further data collection by Mars Odyssey and comparisons with MER and future missions.

Evaluation of Chlorine Treatment Levels for Inactivation of Human Norovirus and MS2 Bacteriophage during Sewage Treatment.

PubMed

Kingsley, David H; Fay, Johnna P; Calci, Kevin; Pouillot, Régis; Woods, Jacquelina; Chen, Haiqiang; Niemira, Brendan A; Van Doren, Jane M

2017-12-01

This study examined the inactivation of human norovirus (HuNoV) GI.1 and GII.4 by chlorine under conditions mimicking sewage treatment. Using a porcine gastric mucin-magnetic bead (PGM-MB) assay, no statistically significant loss in HuNoV binding (inactivation) was observed for secondary effluent treatments of ≤25 ppm total chlorine; for both strains, 50 and 100 ppm treatments resulted in ≤0.8-log 10 unit and ≥3.9-log 10 unit reductions, respectively. Treatments of 10, 25, 50, and 100 ppm chlorine inactivated 0.31, 1.35, >5, and >5 log 10 units, respectively, of the norovirus indicator MS2 bacteriophage. Evaluation of treatment time indicated that the vast majority of MS2 and HuNoV inactivation occurred in the first 5 min for 0.2-μm-filtered, prechlorinated secondary effluent. Free chlorine measurements of secondary effluent seeded with MS2 and HuNoV demonstrated substantial oxidative burdens. With 25, 50, and 100 ppm treatments, free chlorine levels after 5 min of exposure ranged from 0.21 to 0.58 ppm, from 0.28 to 16.7 ppm, and from 11.6 to 53 ppm, respectively. At chlorine treatment levels of >50 ppm, statistically significant differences were observed between reductions for PGM-MB-bound HuNoV (potentially infectious) particles and those for unbound (noninfectious) HuNoV particles or total norovirus particles. While results suggested that MS2 and HuNoV (measured as PGM-MB binding) behave similarly, although not identically, both have limited susceptibility to chlorine treatments of ≤25 ppm total chlorine. Since sewage treatment is performed at ≤25 ppm total chlorine, targeting free chlorine levels of 0.5 to 1.0 ppm, these results suggest that traditional chlorine-based sewage treatment does not inactivate HuNoV efficiently. IMPORTANCE HuNoV is ubiquitous in sewage. A receptor binding assay was used to assess inactivation of HuNoV by chlorine-based sewage treatment, given that the virus cannot be routinely propagated in vitro Results reported here indicate that chlorine treatment of sewage is not effective for inactivating HuNoV unless chlorine levels are above those routinely used for sewage treatment. Copyright © 2017 American Society for Microbiology.

Evaluation of Chlorine Treatment Levels for Inactivation of Human Norovirus and MS2 Bacteriophage during Sewage Treatment

PubMed Central

Fay, Johnna P.; Calci, Kevin; Pouillot, Régis; Woods, Jacquelina; Chen, Haiqiang; Niemira, Brendan A.; Van Doren, Jane M.

2017-01-01

ABSTRACT This study examined the inactivation of human norovirus (HuNoV) GI.1 and GII.4 by chlorine under conditions mimicking sewage treatment. Using a porcine gastric mucin-magnetic bead (PGM-MB) assay, no statistically significant loss in HuNoV binding (inactivation) was observed for secondary effluent treatments of ≤25 ppm total chlorine; for both strains, 50 and 100 ppm treatments resulted in ≤0.8-log10 unit and ≥3.9-log10 unit reductions, respectively. Treatments of 10, 25, 50, and 100 ppm chlorine inactivated 0.31, 1.35, >5, and >5 log10 units, respectively, of the norovirus indicator MS2 bacteriophage. Evaluation of treatment time indicated that the vast majority of MS2 and HuNoV inactivation occurred in the first 5 min for 0.2-μm-filtered, prechlorinated secondary effluent. Free chlorine measurements of secondary effluent seeded with MS2 and HuNoV demonstrated substantial oxidative burdens. With 25, 50, and 100 ppm treatments, free chlorine levels after 5 min of exposure ranged from 0.21 to 0.58 ppm, from 0.28 to 16.7 ppm, and from 11.6 to 53 ppm, respectively. At chlorine treatment levels of >50 ppm, statistically significant differences were observed between reductions for PGM-MB-bound HuNoV (potentially infectious) particles and those for unbound (noninfectious) HuNoV particles or total norovirus particles. While results suggested that MS2 and HuNoV (measured as PGM-MB binding) behave similarly, although not identically, both have limited susceptibility to chlorine treatments of ≤25 ppm total chlorine. Since sewage treatment is performed at ≤25 ppm total chlorine, targeting free chlorine levels of 0.5 to 1.0 ppm, these results suggest that traditional chlorine-based sewage treatment does not inactivate HuNoV efficiently. IMPORTANCE HuNoV is ubiquitous in sewage. A receptor binding assay was used to assess inactivation of HuNoV by chlorine-based sewage treatment, given that the virus cannot be routinely propagated in vitro. Results reported here indicate that chlorine treatment of sewage is not effective for inactivating HuNoV unless chlorine levels are above those routinely used for sewage treatment. PMID:28939600

Determination of Residual Chlorine and Turbidity in Drinking Water. Student Manual.

ERIC Educational Resources Information Center

Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

This student's manual covers analytical methods for residual chlorine and turbidity. Topics include sample handling, permissable concentration levels, substitution of residual chlorine for bacteriological work, public notification, and the required analytical techniques to determine residual chlorine and turbidity. The publication is intended for…

77 FR 21964 - Chlorinated Isocyanurates From the People's Republic of China: Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-12

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... preliminary rescission of the antidumping duty new shipper review (NSR) of chlorinated isocyanurates from the... Review'' section below. \\1\\ See Chlorinated Isocyanurates from the People's Republic of China...

76 FR 6399 - Chlorinated Isocyanurates From the People's Republic of China: Initiation of New Shipper Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-04

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... of the antidumping duty order on chlorinated isocyanurates from the People's Republic of China (``PRC.... SUPPLEMENTARY INFORMATION: Background The notice announcing the antidumping duty order on chlorinated...

21 CFR 177.2430 - Polyether resins, chlorinated.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyether resins, chlorinated. 177.2430 Section... as Components of Articles Intended for Repeated Use § 177.2430 Polyether resins, chlorinated. Chlorinated polyether resins may be safely used as articles or components of articles intended for repeated...

IDENTIFICATION OF DRINKING WATER DISINFECTION BY-PRODUCTS FROM OZONE, CHLORINE DIOXIDE, CHLORAMINE, AND CHLORINE

EPA Science Inventory

Many drinking water treatment plants are currently using alternative disinfectants to treat drinking water, with ozone, chlorine dioxide, and chloramine being the most popular. However, compared to chlorine, which has been much more widely studied, there is little information abo...

Chlorine: Undergraduate Research on an Element of Controversy

NASA Astrophysics Data System (ADS)

Chang, Hasok

2009-04-01

If chemical elements were people, chlorine would be a celebrity. Although intrinsically no more or less important than any other element, chlorine has had a knack of making headlines. The genre of "object biography" has been quite successful in popular science recently. We took this opportunity to write a "biographical" study of chlorine. Chlorine's wide range of interesting controversies is well suited for attracting and maintaining the enthusiasm of the diverse range of students we teach in our department.

Highly chlorinated unintentionally produced persistent organic pollutants generated during the methanol-based production of chlorinated methanes: A case study in China.

PubMed

Zhang, Lifei; Yang, Wenlong; Zhang, Linli; Li, Xiaoxiu

2015-08-01

The formation of unintentionally produced persistent organic pollutants (POPs) may occur during various chlorination processes. In this study, emissions of unintentionally produced POPs during the methanol-based production of chlorinated methanes were investigated. High concentrations of highly chlorinated compounds such as decachlorobiphenyl, octachloronaphthalene, octachlorostyrene, hexachlorobutadiene, hexachlorocyclopentadiene, hexachlorobenzene, and pentachlorobenzene were found in the carbon tetrachloride byproduct of the methanol-based production of chlorinated methanes. The total emission amounts of hexachlorocyclopentadiene, hexachlorobutadiene, polychlorinated benzenes, polychlorinated naphthalenes, octachlorostyrene, and polychlorinated biphenyls released during the production of chlorinated methanes in China in 2010 were estimated to be 10080, 7350, 5210, 427, 212, and 167 kg, respectively. Moreover, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) were formed unintentionally during chlorinated methanes production, the emission factor for PCDDs/DFs was 364 μg toxic equivalency quotient (TEQ) t(-1) product for residues, which should be added into the UNEP toolkit for updating. It was worth noting that a high overall toxic equivalency quotient from polychlorinated naphthalenes and PCDDs/DFs was generated from the chlorinated methanes production in China in 2010. The values reached 563 and 32.8 g TEQ, respectively. The results of the study indicate that more research and improved management systems are needed to ensure that the methanol-based production of chlorinated methanes can be achieved safely. Copyright © 2015 Elsevier Ltd. All rights reserved.

Highly selective transformation of ammonia nitrogen to N2 based on a novel solar-driven photoelectrocatalytic-chlorine radical reactions system.

PubMed

Ji, Youzhi; Bai, Jing; Li, Jinhua; Luo, Tao; Qiao, Li; Zeng, Qingyi; Zhou, Baoxue

2017-11-15

A highly selective method for transforming ammonia nitrogen to N 2 was proposed, based on a novel solar-driven photoelectrocatalytic-chlorine radical reactions (PEC-chlorine) system. The PEC-chlorine system was facilitated by a visible light response WO 3 nanoplate array (NPA) electrode in an ammonia solution containing chloride ions (Cl - ). Under illumination, photoholes from WO 3 promote the oxidation of Cl - to chlorine radical (Cl). This radical can selectively transform ammonia nitrogen to N 2 (79.9%) and NO 3 - (19.2%), similar to the breakpoint chlorination reaction. The ammonia nitrogen removal efficiency increased from 10.6% (PEC without Cl - ) to 99.9% with the PEC-chlorine system within 90 min operation, which can be attributed to the cyclic reactions between Cl - /Cl and the reaction intermediates (NH 2 , NHCl, etc.) that expand the degradation reactions from the surface of the electrodes to the whole solution system. Moreover, Cl is the main radical species contributing to the transformation of ammonia nitrogen to N 2 , which is confirmed by the tBuOH capture experiment. Compared to conventional breakpoint chlorination, the PEC-chlorine system is a more economical and efficient means for ammonia nitrogen degradation because of the fast removal rate, no additional chlorine cost, and its use of clean energy (since it is solar-driven). Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

PubMed

Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

2017-06-01

The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × time reaction ) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, E a , induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (COD Mn ) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and COD Mn concentrations contributed to the inactivation of T. tubifex. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetic modelling of chlorination of nitrided ilmenite using MATLAB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramakrishnan, Sivakumar, E-mail: srsivakumar@usm.my; Kwok, Teong Chen, E-mail: ctck@live.com; Hamid, Sheikh Abdul Rezan Sheikh Abdul, E-mail: rezanshk@gmail.com

In the present study, chlorination of nitride ilmenite using 2{sup k} factorial design was investigated. The reduction experiments were carried out in a temperature range of 400°C to 500°C, chlorination duration from 1 hour to 3 hours and using different type of carbon reactant. Phases of raw materials and reduced samples were analyzed by X-ray diffraction (XRD). Ilmenite was reduced to TiO{sub x}C{sub y}N{sub z} through carbothermal and nitridation for further chlorination into titanium tetrachloride. The Design of Experiment analysis suggested that the types of carbon reactant contribute most influence to the extent of chlorination of nitride ilmenite. The extentmore » of chlorination was highest at 500°C with 3 hours chlorination time and carbon nanotube as carbon reactant.« less

Chlorinated paraffin analysis by gas chromatography Orbitrap high-resolution mass spectrometry: Method performance, investigation of possible interferences and analysis of fish samples.

PubMed

Krätschmer, Kerstin; Cojocariu, Cristian; Schächtele, Alexander; Malisch, Rainer; Vetter, Walter

2018-03-02

For decades, high quantities of short-chain chlorinated paraffins (SCCP) and medium-chain chlorinated paraffins (MCCP) have been widely used, for instance as plasticizers or flame retardants, leading to global pollution due to unintentional emissions from products or waste. Due to the high complexity of chlorinated paraffins with several thousand congeners there is no consensus on an analytical procedure for SCCPs and MCCPs in food samples. Amongst the multitude of methods currently in use, high-resolution mass spectrometry is particularly valuable for in-depth studies of homologue patterns. Here we analyse SCCPs and MCCPs with gas chromatography coupled to high-resolution Orbitrap mass spectrometry (GC-Orbitrap-HRMS) operated in full-scan acquisition in electron capture negative ion (ECNI) mode at 60,000 and 120,000 resolution (FWHM, m/z 200, equals roughly 30,000 and 60,000 at 5% peak height). Linear dynamic range, selectivity and sensitivity tests confirmed an excellent linearity in a concentration range of 25-15,000 pg/μL with very low limits of detection (LODs) in the low pg/μL range. Spiking experiments with high levels of native mono- and di-ortho-polychlorinated biphenyls (PCBs) and mixtures of MCCP and SCCP standards did not have a negative impact on isotope ratios of the examined homologues. Besides the [M-Cl] - fragment ions used for quantification, the mass spectra of homologues also featured [M-HCl] - ions whose abundance increased with decreasing chlorination degree. In addition, [M-HCl-Cl] - ions were detected with a relative abundance of 5-10%. Three salmon (Salmo salar) samples farmed in Norway showed a consistent CP homologue pattern which differed both from the CP pattern in a sample from Scottish aquaculture and a wild salmon sample. These measurements produce evidence that discretely different CP patterns may exist in different areas of origin. Our results demonstrate that GC/ECNI-Orbitrap-HRMS is well-suited for the analysis of CPs by overcoming a range of mass interference problems and due to its thus far unmatched sensitivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Detection, identification and formation of new iodinated disinfection byproducts in chlorinated saline wastewater effluents.

PubMed

Gong, Tingting; Zhang, Xiangru

2015-01-01

The use of seawater for toilet flushing introduces high levels of inorganic ions, including iodide ions, into a city's wastewater treatment systems, resulting in saline wastewater effluents. Chlorination is widely used in disinfecting wastewater effluents owing to its low cost and high efficiency. During chlorination of saline wastewater effluents, iodide may be oxidized to hypoiodous acid, which may further react with effluent organic matter to form iodinated disinfection byproducts (DBPs). Iodinated DBPs show significantly higher toxicity than their brominated and chlorinated analogues and thus have been drawing increasing concerns. In this study, polar iodinated DBPs were detected in chlorinated saline wastewater effluents using a novel precursor ion scan method. The major polar iodinated DBPs were identified and quantified, and their organic precursors and formation pathways were investigated. The formation of iodinated DBPs under different chlorine doses and contact times was also studied. The results indicated that a few polar iodinated DBPs were generated in the chlorinated saline primary effluent, but few were generated in the chlorinated saline secondary effluent. Several major polar iodinated DBPs in the chlorinated saline primary effluent were proposed with structures, among which a new group of polar iodinated DBPs, iodo-trihydroxybenzenesulfonic acids, were identified and quantified. The organic precursors of this new group of DBPs were found to be 4-hydroxybenzenesulfonic acid and 1,2,3-trihydroxybenzene, and the formation pathways of these new DBPs were tentatively proposed. Both chlorine dose and contact time affected the formation of iodinated DBPs in the chlorinated saline wastewater effluents.

The tumor affinity of chlorin e6 and its sonodynamic effects on non-small cell lung cancer.

PubMed

Chen, Bei; Zheng, Ruinian; Liu, Duan; Li, Baofeng; Lin, Jinrong; Zhang, Weimin

2013-03-01

Sonodynamic therapy (SDT) is a promising new approach for cancer therapy. The aim of this study was to investigate the tumor affinity of chlorin e6, a photosensitizer, and its sonodynamic effects on NSCLC. Human lung adenocarcinoma cells SPCA-1 and mice bearing SPCA-1 tumor xenograft were exposed to ultrasound in the presence or absence of chlorin e6. Chlorin e6 distribution was detected by laser scan confocal microscope. Cell apoptosis and necrosis were studied by flow cytometry analysis. Tumor size and weight were measured after different treatments. The concentration of chlorin e6 in tumor tissue was remarkably higher than that in normal muscle near tumor, and the difference was greatest at 18h (the fluorescence intensity was 5.38-fold higher in tumor than in muscle, P<0.05). In vivo, ultrasound (0.4-1.6W/cm(2)) or chlorin e6 (10-40mg/kg) alone had no remarkable anti-tumor effects, but the combination of ultrasound (1.6W/cm(2)) with chlorin e6 (SDT) hampered tumor growth significantly (P<0.05). Intraperitoneal injection of 40mg/kg chlorin e6 exerted no notable side effect on blood, liver and kidney function. Flow cytometry analysis showed that chlorin e6-mediated sonodynamic effect was mainly through the induction of cell necrosis. Chlorin e6 is a promising sonosensitizer and chlorin e6-mediated SDT may provide a new approach for NSCLC therapy. Copyright © 2012 Elsevier B.V. All rights reserved.

40 CFR 63.445 - Standards for the bleaching system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... process using secondary or non-wood fibers, that use chlorine dioxide. (b) The equipment at each bleaching... system. (a) Each bleaching system that does not use any chlorine or chlorinated compounds for bleaching... systems shall meet all the provisions of this section: (1) Bleaching systems that use chlorine; (2...

40 CFR 63.445 - Standards for the bleaching system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... process using secondary or non-wood fibers, that use chlorine dioxide. (b) The equipment at each bleaching... system. (a) Each bleaching system that does not use any chlorine or chlorinated compounds for bleaching... systems shall meet all the provisions of this section: (1) Bleaching systems that use chlorine; (2...

Investigation on chlorine-based sanitization under stabilized conditions in the presence of organic load

USDA-ARS?s Scientific Manuscript database

Chlorine is commonly used for preventing water-mediated cross contamination during fresh produce washing. The sanitization efficacy (SE) is constantly compromised by the organic load (OL), which has been attributed to rapid chlorine depletion and unsuccessful maintenance of residual free chlorine (F...

Chlorine Gas: An Evolving Hazardous Material Threat and Unconventional Weapon

PubMed Central

Jones, Robert; Wills, Brandon; Kang, Christopher

2010-01-01

Chlorine gas represents a hazardous material threat from industrial accidents and as a terrorist weapon. This review will summarize recent events involving chlorine disasters and its use by terrorists, discuss pre-hospital considerations and suggest strategies for the initial management for acute chlorine exposure events. PMID:20823965

40 CFR 704.45 - Chlorinated terphenyl.

Code of Federal Regulations, 2010 CFR

2010-07-01

... chlorinated terphenyl must notify EPA within 15 days after making the management decision described in § 704.3....45 Chlorinated terphenyl. (a) Definitions. (1) Chlorinated terphenyl means a chemical substance, CAS... terphenyl. The notice must include, to the extent that it is known to the person making the report or is...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

75 FR 9160 - Chlorinated Isocyanurates From the People's Republic of China: Notice of Extension of Time Limit...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... administrative review of the antidumping duty order on chlorinated isocyanurates from the People's Republic of... practicable to complete the preliminary results of the administrative review of chlorinated isocyanurates from...

75 FR 62099 - Chlorinated Isocyanurates From the People's Republic of China: Notice of Extension of Time Limit...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-07

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... review of the antidumping order on chlorinated isocyanurates from the People's Republic of China (``PRC... currently due no later than October 12, 2010. \\1\\ See Chlorinated Isocyanurates from the People's Republic...

76 FR 70705 - Chlorinated Isocyanurates From the People's Republic of China: Preliminary Rescission of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... conducting a new shipper review (NSR) of the antidumping duty order on chlorinated isocyanurates from the... Department published the order on chlorinated isocyanurates from the PRC. See Notice of Antidumping Duty...

76 FR 10875 - Chlorinated Isocyanurates From the People's Republic of China: Extension of Time Limit for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-28

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... Department) initiated the administrative review of the antidumping duty order on chlorinated isocyanurates (chlorinated isos) from the People's Republic of China (PRC) covering the period June 1, 2009, through May 31...

75 FR 62764 - Chlorinated Isocyanurates From Spain and the People's Republic of China: Continuation of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-13

... DEPARTMENT OF COMMERCE International Trade Administration [A-469-814, A-570-898] Chlorinated... Commission (``ITC'') that revocation of the antidumping duty orders on chlorinated isocyanurates (``chlorinated isos'') from Spain and the People's Republic of China (``PRC'') would be likely to lead to...

76 FR 41761 - Chlorinated Isocyanurates From the People's Republic of China: Extension of Time Limit for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... Commerce (the Department) initiated a new shipper review under the antidumping duty order on chlorinated...) is June 1, 2010, through December 31, 2010. See Chlorinated Isocyanurates From the People's Republic...

75 FR 70212 - Chlorinated Isocyanurates From the People's Republic of China: Final Results of 2008-2009...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-17

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... administrative review of the antidumping duty order on chlorinated isocyanurates from the People's Republic of... on chlorinated isocyanurates from the PRC.\\1\\ On June 3, 2010, Hebei Jiheng Chemical Corporation, Ltd...

76 FR 41760 - Chlorinated Isocyanurates From the People's Republic of China: Extension of Time Limit for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... Commerce (the Department) initiated a new shipper review under the antidumping duty order on chlorinated...) is June 1, 2010, through December 31, 2010. See Chlorinated Isocyanurates From the People's Republic...

75 FR 56988 - Chlorinated Isocyanurates From the People's Republic of China: Notice of Extension of Time Limit...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-17

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... review of the antidumping order on chlorinated isocyanurates from the People's Republic of China (``PRC... currently due no later than September 11, 2010. \\1\\ See Chlorinated Isocyanurates from the People's Republic...

77 FR 4990 - Chlorinated Isocyanurates From the People's Republic of China: Extension of Time Limit for Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... shipper review under the antidumping duty order on chlorinated isocyanurates from the People's Republic of... 31, 2010. See Chlorinated Isocyanurates from the People's Republic of China: Preliminary Rescission...

ALTERNATIVES TO CHLORINATION FOR CONTROL OF CONDENSER TUBE BIO-FOULING

EPA Science Inventory

The report gives results of a study of methods used to reduce free-chlorine residuals in power plant effluents. Most U.S. power plants use chlorine (28,600 tons in 1972) to control biological fouling in their cooling systems, particularly in their condenser tubes. Using chlorine ...

76 FR 70957 - Chlorinated Isocyanurates From the People's Republic of China: Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-16

... From the People's Republic of China: Final Results of Antidumping Duty Administrative Review AGENCY... on chlorinated isocyanurates (chlorinated isos) from the People's Republic of China (PRC). The period...'' section below. \\1\\ See Chlorinated Isocyanurates From the People's Republic of China: Preliminary Results...

Evaluation of gaseous chlorine dioxide for the inactivation of tulane virus on blueberries

USDA-ARS?s Scientific Manuscript database

To determine the effectiveness of gaseous chlorine dioxide against a human norovirus surrogate on produce, chlorine dioxide was generated and applied to Tulane virus coated blueberries in a 240 ml treatment chamber. Chlorine dioxide was produced by acidifying sodium chlorite solution. Initial asse...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

Synthesis, Structure and Antitumour Properties of a New 1,2-Propylenediaminetetraacetate-Ruthenium(III) Compound

PubMed Central

Vilaplana, R.; Romero, M. A.; Quirós, M.; Salas, J. M.

1995-01-01

A novel complex formed by ruthenium (III) and the sequestering ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been synthetized and characterized. The structure of the monomeric compound, studied by X-ray diffraction , shows an almost symmetric octahedral geometry around the metal ion, with two chlorine atoms in a cis conformation. The antitumour activity against a variety of murine and human cancers is reported. PMID:18472768

A Summary of Publications on the Development of Mode-of ...

EPA Pesticide Factsheets

Chemical contaminants are formed as a consequence of chemical disinfection of public drinking waters. Chemical disinfectants, which are used to kill harmful microorganisms, react with natural organic matter (NOM), bromide, iodide, and other compounds, forming complex mixtures of potentially toxic disinfection byproducts (DBPs). The types and concentrations of DBPs formed during disinfection and the relative proportions of the components vary depending on factors such as source water conditions (e.g., types of NOM present), disinfectant type (e.g., chlorine, ozone, chloramine), and treatment conditions (e.g., pH and temperature). To date, over 500 DBPs have been detected in treated waters. However, typically more than 50% of the organic halide mass produced by chlorination disinfection consists of unidentified chemicals, which are not measured by routine analyses of DBPs. The protocols and methods typically used to evaluate chemical mixtures are best applied to simple defined mixtures consisting of relatively few chemicals. These approaches rely on assumptions (e.g., common mode of action, independent toxic action) regarding the type of joint toxic action (e.g., dose-additivity, synergism) that might be observed. Such methods, used for site assessments or toxicological studies, are often not sufficient to estimate health risk for complex drinking water DBP mixtures. Actual drinking water exposures involve multiple chemicals, many of w

New Generation of Photosensitizers: Conjugates of Chlorin e 6 With Diamond Nanoparticles

NASA Astrophysics Data System (ADS)

Lapina, V. A.; Bushuk, S. B.; Pavich, T. A.; Vorobey, A. V.

2016-07-01

Conjugates of chlorin e 6 with diamond nanoparticles were synthesized by two methods. The spectral and luminescent properties of the obtained conjugates were studied. It was shown that chlorin e 6 retained its photosensitizing activity in the conjugate. It was established that chlorin e 6 immobilized directly on diamond nanoparticles had higher photosensitizing activity than that conjugated using a spacer. It was observed that chlorin e 6 in the conjugate had higher photolytic stability than the free form.

Calculating Toxic Corridors. Revision

DTIC Science & Technology

1989-04-01

16 Table 9 Chlorine Pentafluoride 1CL ........... ................... .. 17 Table 10 Chlorine Trifluoride TCL...60-min EEL: 3.0 ppm 31 Chlorine Pentafluoride 130.445 0.3 4.64 1.5 1(T) 2.03 Mone - (T) - Tentative Chlorine Trifluoride 92.448 0.63 3.88 3.01 1.70...CIF 5 770.4 Chlorine Trifluoride 26.6 1,B33.410 54.141 80 92.448 CIF.3 247.2 Diborane 16.859 B2 H Ethylene- Oxide 27.0 f 1,860.98 54.96 80 44.054 C

Application of activated carbons from coal and coconut shell for removing free residual chlorine.

PubMed

Ogata, Fumihiko; Tominaga, Hisato; Ueda, Ayaka; Tanaka, Yuko; Iwata, Yuka; Kawasaki, Naohito

2013-01-01

This study investigated the removal of free residual chlorine by activated carbon (AC). ACs were prepared from coal (AC1) and coconut shell (AC2). The specific surface area of AC1 was larger than that of AC2. The removal of free residual chlorine increased with elapsed time and amount of adsorbent. The removal mechanism of free residual chlorine was the dechlorination reaction between hypochlorous acid or hypochlorite ion and AC. Moreover, AC1 was useful in the removal of free residual chlorine in tap water. The optimum condition for the removal of free residual chlorine using a column is space velocity 306 1/h; liner velocity 6.1 m/h.

Room Temperature Halogenation of Polyimide Film Surface using Chlorine Trifluoride Gas

NASA Astrophysics Data System (ADS)

Habuka, Hitoshi; Kosuga, Takahiro; Koike, Kunihiko; Aida, Toshihiro; Takeuchi, Takashi; Aihara, Masahiko

2004-02-01

In order to develop a new application of chlorine trifluoride gas, the halogenation of a polyimide film surface at room temperature and at atmospheric pressure is studied for the first time. The polyimide film surface after exposure to the chlorine trifluoride gas shows a decreased water contact angle with increasing chlorine trifluoride gas concentration and exposure period. Since both X-ray photoelectron spectroscopy and infrared absorption spectroscopy simultaneously showed the formation of a carbon-chlorine bond and carbon-fluorine bond, it is concluded that the chlorine trifluoride gas can easily and safely perform the halogenation of the polyimide film surface under the stated conditions using a low-cost process and equipment.

Chlorine decay and trihalomethane formation following ferrate(VI) preoxidation and chlorination of drinking water.

PubMed

Li, Cong; Luo, Feng; Dong, Feilong; Zhao, Jingguo; Zhang, Tuqiao; He, Guilin; Cizmas, Leslie; Sharma, Virender K

2017-11-01

This paper presents the effect of preoxidation with ferrate(VI) (Fe VI O 4 2- , Fe(VI)) prior to chlorination on chlorine decay and formation of disinfection by-products in filtered raw water from a full-scale drinking water treatment plant. The rate of chlorine decay became significantly faster as the concentration of ferrate(VI) increased. Chlorine degradation followed two first-order decay reactions with rate constants k 1 and k 2 for fast and slow decay, respectively. Kinetic modeling established the relationships between k 1 and k 2 and varying dosages of chlorine and ferrate(VI). When ferrate(VI) was used as a pre-oxidant, the levels of trihalomethanes (trichloromethane (TCM), dichlorobromomethane (DCBM), dibromochloromethane (DBCM), and tribromomethane (TBM)) in water samples decreased as the ferrate(VI) concentration increased. The concentrations of these trihalomethanes followed the order TCM > DCBM ≈ DBCM > TBM. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorine adsorption on the InAs (001) surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakulin, A. V.; Eremeev, S. V.; Tereshchenko, O. E.

2011-01-15

Chlorine adsorption on the In-stabilized InAs(001) surface with {zeta}-(4 Multiplication-Sign 2) and {beta}3 Prime -(4 Multiplication-Sign 2) reconstructions and on the Ga-stabilized GaAs (001)-{zeta}-(4 Multiplication-Sign 2) surface has been studied within the electron density functional theory. The equilibrium structural parameters of these reconstructions, surface atom positions, bond lengths in dimers, and their changes upon chlorine adsorption are determined. The electronic characteristics of the clean surface and the surface with adsorbed chlorine are calculated. It is shown that the most energetically favorable positions for chlorine adsorption are top positions over dimerized indium or gallium atoms. The mechanism of chlorine binding withmore » In(Ga)-stabilized surface is explained. The interaction of chlorine atoms with dimerized surface atoms weakens surface atom bonds and controls the initial stage of surface etching.« less

Fatal chlorine gas exposure at a metal recycling facility: Case report.

PubMed

Harvey, Robert R; Boylstein, Randy; McCullough, Joel; Shumate, Alice; Yeoman, Kristin; Bailey, Rachel L; Cummings, Kristin J

2018-06-01

At least four workers at a metal recycling facility were hospitalized and one died after exposure to chlorine gas when it was accidentally released from an intact, closed-valved cylinder being processed for scrap metal. This unintentional chlorine gas release marks at least the third such incident at a metal recycling facility in the United States since 2010. We describe the fatal case of the worker whose clinical course was consistent with acute respiratory distress syndrome (ARDS) following exposure to high concentrations of chlorine gas. This case report emphasizes the potential risk of chlorine gas exposure to metal recycling workers by accepting and processing intact, closed-valved containers. The metal recycling industry should take steps to increase awareness of this established risk to prevent future chlorine gas releases. Additionally, public health practitioners and clinicians should be aware that metal recycling workers are at risk for chlorine gas exposure. © 2018 Wiley Periodicals, Inc.

40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must also...

40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must also...

40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must also...

40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must also...

HPLC DETERMINATION OF CYANURIC ACID IN SWIMMING POOL WATERS USING PHENYL AND CONFIRMATORY POROUS GRAPHITIC CARBON COLUMNS

EPA Science Inventory

The chlorinated salts of cyanuric acid have found an important role in recreational swimming pool waters across the United States. Upon application to pool water, they can (1) release disinfectant chlorine or (2) stabilize the free available chlorine by acting as chlorine reserv...

Biodegration of chlorinated ethenes

USGS Publications Warehouse

Bradley, Paul M.; Chapelle, Francis H.

2010-01-01

Biodegradation of chlorinated ethenes by naturally occurring or artificially enhanced processes is an important component of current site remediation strategies. At this writing, several microbial mechanisms for chlorinated ethene transformation and degradation have been identified. The purpose of this chapter is to briefly summarize the current understanding of those processes that lead to the biodegradation of chlorinated ethenes.

75 FR 76699 - Chlorinated Isocyanurates From the People's Republic of China: Notice of Correction to the Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-09

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-898] Chlorinated Isocyanurates... antidumping duty order on chlorinated isocyanurates from the People's Republic of China (``PRC'').\\1\\ The... final results margin for Jiheng for the 2008-2009 period of review is 2.66 percent. \\1\\ See Chlorinated...

New wash aid T-128 improves efficacy of chlorine against cross contamination by bacterial pathogens in fresh-cut lettuce processing

USDA-ARS?s Scientific Manuscript database

Chlorinated water is widely used as the primary anti-microbial intervention during fresh-cut produce processing. Free chlorine in chlorinated water can provide effective reduction of potential contaminations by microbial pathogens, and, more importantly, effectively prevent cross contamination of p...

Selective recovery of uranium from Ca-Mg uranates by chlorination

NASA Astrophysics Data System (ADS)

Pomiro, Federico J.; Gaviría, Juan P.; Quinteros, Raúl D.; Bohé, Ana E.

2017-07-01

A chlorination process is proposed for the uranium extraction and separation using Calciumsbnd Magnesium uranates such as starting reactants which were obtained by precipitation from uranyl nitrate solutions with calcium hydroxide. The study is based on thermodynamic and reaction analysis using chlorine gas as chlorination agent. The results showed that the chlorination reaction of Ca uranate is more feasible to occur than the Mg uranate. The products obtained after chlorination reactions were washed with deionized water to remove the chlorides produced and analyzed. The XRD patterns of the washed products indicated that the chlorination between 400 and 500 °C result in a single phase of calcium uranate (CaUO4) as reaction product. The formation of U3O8 and MgU3O10 was observed at temperatures between 600 °C and 700 °C for 8 hs. The optimal conditions to recover uranium were 3 l h-1 of chlorine and 10 hs of reaction at 700 °C being U3O8 the single uranium product obtained.

Fate of Antibiotic Resistant Bacteria and Genes during Wastewater Chlorination: Implication for Antibiotic Resistance Control

PubMed Central

Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

2015-01-01

This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L). The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L). By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L). However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination. PMID:25738838

Chlorine inactivation of human norovirus, murine norovirus and poliovirus in drinking water.

PubMed

Kitajima, M; Tohya, Y; Matsubara, K; Haramoto, E; Utagawa, E; Katayama, H

2010-07-01

To evaluate the reduction of human norovirus (HuNoV) by chlorine disinfection under typical drinking water treatment conditions. HuNoV, murine norovirus (MNV) and poliovirus type 1 (PV1) were inoculated into treated water before chlorination, collected from a drinking water treatment plant, and bench-scale free chlorine disinfection experiments were performed for two initial free chlorine concentrations, 0.1 and 0.5 mg l(-1). Inactivation of MNV reached more than 4 log(10) after 120 and 0.5 min contact time to chlorine at the initial free chlorine concentrations of 0.1 and 0.5 mg l(-1), respectively. MNV was inactivated faster than PV1, and there was no significant difference in the viral RNA reduction rate between HuNoV and MNV. The results suggest that appropriate water treatment process with chlorination can manage the risk of HuNoV infection via drinking water supply systems. The data obtained in this study would be useful for assessing or managing the risk of HuNoV infections from drinking water exposure.

Chlorine dioxide as a post-disinfectant for Dutch drinking water.

PubMed

Wondergem, E; van Dijk-Looijaard, A M

1991-02-01

Chlorine dioxide has some important advantages over chlorine with respect to water quality (no formation of trihalomethanes, no impairment of taste and no odor) and stability when used for oxidation/disinfection of drinking water. In this paper, results are presented of experiments into the consumption and reaction kinetics of chlorine dioxide in a number of (drinking) waters in The Netherlands. It was found that chlorine dioxide consumption is related to the dissolved oxygen content (DOC) of the water and the reaction time. Water samples from a plant that applied ozonation and activated carbon filtration had a very low chlorine dioxide consumption. Other water quality parameters, including pH and CO3(2-), did not have any influence on consumption. The temporary advised Dutch guidelines of 0.2 mg l-1 (dosage) is sufficient for activated carbon treated water. For other Dutch drinking waters, however, none of the 0.2 mg l-1 chlorine dioxide remained after a reaction time of 10 min, as was also found for the water of Dutch pumping stations where chlorine dioxide is at present used for disinfection.

Water in the Lunar Interior and the Apparent KREEP-Mare Dichotomy

NASA Astrophysics Data System (ADS)

McCubbin, F. M.; Nekvasil, H.

2010-12-01

Recent SIMS analysis of lunar apatite has shown that hydroxyl is structurally bound within lunar apatite from a number of different lunar lithologic types (McCubbin et al., 2010a, 2010b; Boyce et al., 2010; Greenwood et al., 2010). These studies along with previous SIMS analyses of lunar fire fountain glasses (Saal et al., 2008) confirm that there is at least some water in the lunar interior, with abundance estimates in magmatic source regions ranging from 64 ppb to 5 ppm water (McCubbin et al., 2010a). Surprisingly, apatite from rocks with KREEP-rich incompatible trace element signatures are depleted in hydroxyl in comparison to apatite from typical mare basalts. This result is counter-intuitive to the lunar magma ocean model, which predicts that incompatible constituents (e.g., water) would have been concentrated in the last dregs of liquid referred to as “urKREEP”. The mare basalts, which formed by partial melting of earlier LMO cumulates, are typically depleted in these incompatible constituents. Complicating the issue further, chlorine, another incompatible magmatic volatile element in apatite, follows the predicted trend with apatite from KREEP-rich rocks containing significant chlorine concentrations in comparison to apatite from mare basalts (McCubbin et al., 2009). The preceding results imply one of two scenarios 1) Water did not behave incompatibly during LMO crystallization and was preferentially stored within the LMO cumulate minerals 2) A secondary process such as degassing has perturbed the initial volatile contents of the urKREEP liquid or of the secondary magmas that have KREEP-rich incompatible trace element signatures. In regards to the first scenario, the mineral melt partition coefficients for water would need to have exceeded unity at the very low water concentrations of the LMO liquid. This scenario is consistent with the behavior of chlorine, as chlorine is not typically stored in nominally anhydrous phases like pyroxene or olivine, likely due to its large ionic radius. However, there is no empirical or experimental evidence to support the elevated D values for water. Regarding the second scenario, if significant degassing of the urKREEP liquid or KREEP-rich secondary magmas occurred, water would have certainly been lost preferentially to the other volatile constituents in apatite (fluorine and chlorine); however chlorine isotopes analyzed in lunar apatites are highly fractionated (Sharp et al., 2010), indicating degassing of chlorine in the absence of water. Therefore, this scenario only works if degassing on the Moon was a multi-stage and complex process where water and chlorine degassing are decoupled, which is not typically the case for terrestrial systems (Aiuppa et al., 2009, Webster and De Vivo, 2002; Webster et al., 1999). Solving this apparent KREEP-mare dichotomy regarding magmatic volatiles in the lunar interior is the next important step in figuring out the importance, relevance, and implications of water in the lunar interior. Moreover, it will lend insight into the roles of the other magmatic volatiles during the thermal and magmatic evolution of the Moon.

Combined toxicity effects of chlorine, ammonia, and temperature on marine plankton. Progress report, February 1, 1975--September 15, 1975

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryther, J. H.; Goldman, J. C.

1975-10-01

Research on the combined effects of chlorine, ammonia, and temperature on marine plankton have been carried out for 7/sup 1///sub 2/ months. Continuous-flow bioassay units have been constructed for larval species, juvenile fish, and phytoplankton. A detailed study on lobster (Homarus americanus) larvae and other studies on killifish (Fundulus heteroclitus) larvae and juveniles, and juvenile scup (Stenotomus versicolor) and winter flounder (Pseudopleuronectes americanus) have been performed. Results to date indicate that there is an apparent and, as yet undetermined, chlorine demand of seawater; there is a differential toxic effect of chlorine and chloramines--lobsters were more sensitive to chloramines, whereas themore » fish species were more affected by free chlorine; respiration results indicate that significant stress occurs at toxicant levels below the onset of mortality, thus raising questions regarding the applicability of standard bioassay data; temperature elevation exerts a strong synergistic effect on chlorine-chloramine toxicity; and effects of exposure to halogen toxicity appear irreversible as revealed by persistent reductions in metabolic activity. It appears that chlorine toxicity to marine biota can occur even though chlorine residuals cannot be detected by current analytical techniques. These results support the findings of others that chlorine toxicity is a serious environmental pollutant. (auth)« less

Degradation Products of Benzophenone-3 in Chlorinated Seawater Swimming Pools.

PubMed

Manasfi, Tarek; Storck, Veronika; Ravier, Sylvain; Demelas, Carine; Coulomb, Bruno; Boudenne, Jean-Luc

2015-08-04

Oxybenzone (2-hydroxy-4-methoxyphenone, benzophenone-3) is one of the UV filters commonly found in sunscreens. Its presence in swimming pools and its reactivity with chlorine has already been demonstrated but never in seawater swimming pools. In these pools, chlorine added for disinfection results in the formation of bromine, due to the high levels of bromide in seawater, and leads to the formation of brominated disinfection byproducts, known to be more toxic than chlorinated ones. Therefore, it seems important to determine the transformation products of oxybenzone in chlorinated seawater swimming pools; especially that users of seawater swimming pools may apply sunscreens and other personal-care products containing oxybenzone before going to pools. This leads to the introduction of oxybenzone to pools, where it reacts with bromine. For this purpose, the reactivity of oxybenzone has been examined as a function of chlorine dose and temperature in artificial seawater to assess its potential to produce trihalomethanes and to determine the byproducts generated following chlorination. Increasing doses of chlorine and increasing temperatures enhanced the formation of bromoform. Experiments carried out with excess doses of chlorine resulted in the degradation of oxybenzone and allowed the determination of the degradation mechanisms leading to the formation of bromoform. In total, ten transformation products were identified, based on which the transformation pathway was proposed.

Detection of chlorine with concentration of 0.18 kg/m{sup 3} in concrete by laser-induced breakdown spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugiyama, K.; Fujii, T.; Matsumura, T.

2010-05-01

The chlorine concentration in concrete samples was measured by laser-induced breakdown spectroscopy (LIBS). One or two pulsed second harmonic Nd:YAG lasers ({lambda}=532 nm) were used for the generation of laser-induced breakdown, and an intensified CCD camera, spectrometer, and optical bundle fiber were used for spectral measurement. To maximize the spectral intensity of the chlorine fluorescence line at a wavelength of 837.59 nm, the time delay between laser irradiation and spectral measurement, the time delay between the two laser pulses in double-pulse measurement, and the gate width of the spectral measurement were optimized. The linear relationship between the spectral intensity ofmore » the chlorine fluorescence line and the chlorine concentration was verified for pressed samples with chlorine concentrations from 0.18 to 5.4 kg/m{sup 3}. The signal-to-noise ratio was higher than 2 for the sample with a chlorine concentration of 0.18 kg/m{sup 3} (0.008 wt. %). Thus, a chlorine concentration of 0.6 kg/m{sup 3}, at which the reinforcing bars in concrete structures start to corrode, can be detected. These results show that LIBS is effective for the quantitative measurement of chlorine concentration in concrete with high sensitivity.« less

Study on encapsulation of chlorine dioxide in gelatin microsphere for reducing release rate

PubMed Central

Ci, Ying; Wang, Lin; Guo, Yanchuan; Sun, Ruixue; Wang, Xijie; Li, Jinyou

2015-01-01

Objective: This study aims to explore the effects of encapsulation of chlorine dioxide in a hydrophilic biodegradable polymer gelatin to reduce its release rate. Methods: An emulsification-coacervation method was adopted. The characterizations of chlorine dioxide-gelatin microspheres were described. Using UV-vis spectrophotometer the λmax of chlorine dioxide was observed at 358 nm. The particle size and distribution of chlorine oxide-gelatin microspheres was measured by a dynamic light scattering (DLS) method, the diameter was (1400~1900) nm. The entrapment of chlorine dioxide-gelatin microspheres was confirmed by IR. The surface morphology, size, and shape of chlorine dioxide-gelatin microspheres were analyzed using Scanning electron microscope (SEM). Results: It showed that the encapsulated microspheres size was around 2000 nm with uniform distribution. The percentage entrapment of chlorine dioxide in the encapsulated samples was about 80~85%. A slow release study of chlorine dioxide from the encapsulated biopolymer (gelatin) in air was also carried out, which showed continuous release up to ten days. Conclusions: It can be concluded that it is possible to make a slow release formulation of ClO2 by entrapped in a hydrophilic biodegradable polymer gelatin. ClO2-gelatin microspheres can stable release low concentration ClO2 gas over an extended period. PMID:26550151

Relationship between antibiotic- and disinfectant-resistance profiles in bacteria harvested from tap water.

PubMed

Khan, Sadia; Beattie, Tara K; Knapp, Charles W

2016-06-01

Chlorination is commonly used to control levels of bacteria in drinking water; however, viable bacteria may remain due to chlorine resistance. What is concerning is that surviving bacteria, due to co-selection factors, may also have increased resistance to common antibiotics. This would pose a public health risk as it could link resistant bacteria in the natural environment to human population. Here, we investigated the relationship between chlorine- and antibiotic-resistances by harvesting 148 surviving bacteria from chlorinated drinking-water systems and compared their susceptibilities against chlorine disinfectants and antibiotics. Twenty-two genera were isolated, including members of Paenibacillus, Burkholderia, Escherichia, Sphingomonas and Dermacoccus species. Weak (but significant) correlations were found between chlorine-tolerance and minimum inhibitory concentrations against the antibiotics tetracycline, sulfamethoxazole and amoxicillin, but not against ciprofloxacin; this suggest that chlorine-tolerant bacteria are more likely to also be antibiotic resistant. Further, antibiotic-resistant bacteria survived longer than antibiotic-sensitive organisms when exposed to free chlorine in a contact-time assay; however, there were little differences in susceptibility when exposed to monochloramine. Irrespective of antibiotic-resistance, spore-forming bacteria had higher tolerance against disinfection compounds. The presence of chlorine-resistant bacteria surviving in drinking-water systems may carry additional risk of antibiotic resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multi-element compound specific stable isotope analysis of chlorinated aliphatic contaminants derived from chlorinated pitches.

PubMed

Filippini, Maria; Nijenhuis, Ivonne; Kümmel, Steffen; Chiarini, Veronica; Crosta, Giovanni; Richnow, Hans H; Gargini, Alessandro

2018-05-30

Tetrachloroethene and trichloroethene are typical by-products of the industrial production of chloromethanes. These by-products are known as "chlorinated pitches" and were often dumped in un-contained waste disposal sites causing groundwater contaminations. Previous research showed that a strongly depleted stable carbon isotope signature characterizes chlorinated compounds associated with chlorinated pitches whereas manufactured commercial compounds have more enriched carbon isotope ratios. The findings were restricted to a single case study and one element (i.e. carbon). This paper presents a multi-element Compound-Specific Stable Isotope Analysis (CSIA, including carbon, chlorine and hydrogen) of chlorinated aliphatic contaminants originated from chlorinated pitches at two sites with different hydrogeology and different producers of chloromethanes. The results show strongly depleted carbon signatures at both sites whereas the chlorine and the hydrogen signatures are comparable to those presented in the literature for manufactured commercial compounds. Multi-element CSIA allowed the identification of sources and site-specific processes affecting chloroethene transformation in groundwater as a result of emergency remediation measures. CSIA turned out to be an effective forensic tool to address the liability for the contamination, leading to a conviction for the crimes of unintentional aggravated public water supply poisoning and environmental disaster. Copyright © 2018 Elsevier B.V. All rights reserved.

Amide Link Scission in the Polyamide Active Layers of Thin-Film Composite Membranes upon Exposure to Free Chlorine: Kinetics and Mechanisms.

PubMed

Powell, Joshua; Luh, Jeanne; Coronell, Orlando

2015-10-20

The volume-averaged amide link scission in the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine was quantified at a variety of free chlorine exposure times, concentrations, and pH and rinsing conditions. The results showed that (i) hydroxyl ions are needed for scission to occur, (ii) hydroxide-induced amide link scission is a strong function of exposure to hypochlorous acid, (iii) the ratio between amide links broken and chlorine atoms taken up increased with the chlorination pH and reached a maximum of ∼25%, (iv) polyamide disintegration occurs when high free chlorine concentrations, alkaline conditions, and high exposure times are combined, (v) amide link scission promotes further chlorine uptake, and (vi) scission at the membrane surface is unrepresentative of volume-averaged scission in the active layer. Our observations are consistent with previously proposed mechanisms describing amide link scission as a result of the hydrolysis of the N-chlorinated amidic N-C bond due to nucleophilic attack by hydroxyl ions. This study increases the understanding of the physicochemical changes that could occur for membranes in treatment plants using chlorine as an upstream disinfectant and the extent and rate at which those changes would occur.

A temperature-programmed X-ray photoelectron spectroscopy (TPXPS) study of chlorine adsorption and diffusion on Ag(1 1 1)

NASA Astrophysics Data System (ADS)

Piao, H.; Adib, K.; Barteau, Mark A.

2004-05-01

Synchrotron-based temperature programmed X-ray photoelectron spectroscopy (TPXPS) has been used to investigate the surface chloridation of Ag(1 1 1) to monolayer coverages. At 100 K both atomic and molecular chlorine species are present on the surface; adsorption at 300 K or annealing the adlayer at 100 K to this temperature generates adsorbed Cl atoms. As the surface is heated from 300 to 600 K, chlorine atoms diffuse below the surface, as demonstrated by attenuation of the Cl2p signals in TPXPS experiments. Quantitative analysis of the extent of attenuation is consistent with chlorine diffusion below the topmost silver layer. For coverages in the monolayer and sub-monolayer regime, chlorine diffusion to and from the bulk appears not to be significant, in contrast to previous results obtained at higher chlorine loadings. Chlorine is removed from the surface at 650-780 K by desorption as AgCl. These results demonstrate that chlorine diffusion beneath the surface does occur at coverages and temperatures relevant to olefin epoxidation processes carried out on silver catalysts with chlorine promoters. The surface sensitivity advantages of synchrotron-based XPS experiments were critical to observing Cl diffusion to the sub-surface at low coverages.

Chlorine dioxide reactions with indoor materials during building disinfection: surface uptake.

PubMed

Hubbard, Heidi; Poppendieck, Dustin; Corsi, Richard L

2009-03-01

Chlorine dioxide received attention as a building disinfectant in the wake of Bacillus anthracis contamination of several large buildings in the fall of 2001. It is increasingly used for the disinfection of homes and other indoor environments afflicted by mold. However, little is known regarding the interaction of chlorine dioxide and indoor materials, particularly as related to the removal of chlorine dioxide from air. Such removal may be undesirable with respect to the subsequent formation of localized zones of depleted disinfectant concentrations and potential reductions in disinfection effectiveness in a building. The focus of this paper is on chlorine dioxide removal from air to each of 24 different indoor materials. Experiments were completed with materials housed in flow-through 48-L stainless steel chambers under standard conditions of 700 ppm chlorine dioxide inlet concentration, 75% relative humidity, 24 degrees C, and 0.5 h(-1) air changes. Chlorine dioxide concentration profiles, deposition velocities, and reaction probabilities are described in this paper. Deposition velocities and reaction probabilities varied over approximately 2 orders of magnitude across all materials. For most materials, deposition velocity decreased significantly over a 16-h disinfection period; that is, materials became smaller sinks for chlorine dioxide with time. Four materials (office partition, ceiling tile, medium density fiberboard, and gypsum wallboard) accounted for the most short- and long-term consumption of chlorine dioxide. Deposition velocity was observed to be a strong function of chlorine dioxide inlet concentration, suggesting the potential importance of chemical reactions on or within test materials.

Dechlorination and chlorine rearrangement of 1,2,5,5,6,9,10-heptachlorodecane mediated by the whole pumpkin seedlings.

PubMed

Li, Yanlin; Hou, Xingwang; Yu, Miao; Zhou, Qunfang; Liu, Jiyan; Schnoor, Jerald L; Jiang, Guibin

2017-05-01

Short chain chlorinated paraffins (SCCPs) are ubiquitously present as persistent organic pollutants in the environment. However, little information on the interaction of SCCPs with plants is currently available. In this work, young pumpkin plants (Cucurbita maxima × C. Moschata) were hydroponically exposed to the congener of chlorinated decane, 1,2,5,5,6,9,10-heptachlorodecane (1,2,5,5,6,9,10-HepCD), to investigate the uptake, translocation and transformation of chlorinated decanes in the intact plants. It was found that parent HepCD was taken up by the pumpkin roots, translocated from root to shoots, and phytovolatilized from pumpkin plants to air via the plant transpiration flux. Our data suggested that dechlorination of 1,2,5,5,6,9,10-HepCD to lower chlorinated decanes and rearrangement of chlorine atoms in the molecule were all mediated by the whole pumpkin seedlings. Chlorinated decanes were found in the shoots and roots of blank controls, indicating that chlorinated decanes in the air could be absorbed by leaves and translocated from shoots to roots. Lower chlorinated congeners (C 10 H 17 Cl 5 ) tended to detain in air compared to higher chlorinated congeners (C 10 H 16 Cl 6 and other C 10 H 15 Cl 7 ). Potential transformation pathway and behavior of 1,2,5,5,6,9,10-HepCD in pumpkin were proposed based on these experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of fuels and domestic heating appliance types on emission factors of selected organic pollutants.

PubMed

Šyc, Michal; Horák, Jiří; Hopan, František; Krpec, Kamil; Tomšej, Tomáš; Ocelka, Tomáš; Pekárek, Vladimír

2011-11-01

This study reports on the first complex data set of emission factors (EFs) of selected pollutants from combustion of five fuel types (lignite, bituminous coal, spruce, beech, and maize) in six different domestic heating appliances of various combustion designs. The effect of fuel as well as the effect of boiler type was studied. In total, 46 combustion runs were performed, during which numerous EFs were measured, including the EFs of particulate matter (PM), carbon monoxide, polyaromatic hydrocarbons (PAH), hexachlorobenzene (HxCBz), polychlorinated dibenzo-p-dioxins and furans (PCDD/F), etc. The highest EFs of nonchlorinated pollutants were measured for old-type boilers with over-fire and under-fire designs and with manual stoking and natural draft. Emissions of the above-mentioned pollutants from modern-type boilers (automatic, downdraft) were 10 times lower or more. The decisive factor for emission rate of nonchlorinated pollutants was the type of appliance; the type of fuel plays only a minor role. Emissions of chlorinated pollutants were proportional mainly to the chlorine content in fuel, but the type of appliance also influenced the rate of emissions significantly. Surprisingly, higher EFs of PCDD/F from combustion of chlorinated bituminous coal were observed for modern-type boilers (downdraft, automatic) than for old-type ones. On the other hand, when bituminous coal was burned, higher emissions of HxCBz were found for old-type boilers than for modern-type ones.

Detection of Legionella, L. pneumophila and Mycobacterium Avium Complex (MAC) along Potable Water Distribution Pipelines

PubMed Central

Whiley, Harriet; Keegan, Alexandra; Fallowfield, Howard; Bentham, Richard

2014-01-01

Inhalation of potable water presents a potential route of exposure to opportunistic pathogens and hence warrants significant public health concern. This study used qPCR to detect opportunistic pathogens Legionella spp., L. pneumophila and MAC at multiple points along two potable water distribution pipelines. One used chlorine disinfection and the other chloramine disinfection. Samples were collected four times over the year to provide seasonal variation and the chlorine or chloramine residual was measured during collection. Legionella spp., L. pneumophila and MAC were detected in both distribution systems throughout the year and were all detected at a maximum concentration of 103 copies/mL in the chlorine disinfected system and 106, 103 and 104 copies/mL respectively in the chloramine disinfected system. The concentrations of these opportunistic pathogens were primarily controlled throughout the distribution network through the maintenance of disinfection residuals. At a dead-end and when the disinfection residual was not maintained significant (p < 0.05) increases in concentration were observed when compared to the concentration measured closest to the processing plant in the same pipeline and sampling period. Total coliforms were not present in any water sample collected. This study demonstrates the ability of Legionella spp., L. pneumophila and MAC to survive the potable water disinfection process and highlights the need for greater measures to control these organisms along the distribution pipeline and at point of use. PMID:25046636

High-resolution Measurements of Gas-Phase Hydrogen Chloride (HCl) in the Atmosphere by Cavity Ring Down Spectroscopy

NASA Astrophysics Data System (ADS)

Hoffnagle, John; Chen, Hongbing; Lee, Jim; Rella, Chris; Kim-Hak, David; Winkler, Renato; Markovic, Milos; Veres, Patrick

2017-04-01

Halogen radical species, such as chlorine and bromine atoms and their oxides, can greatly affect the chemical composition of the troposphere. Hydrogen chloride is the dominant (gas-phase) contributor to the tropospheric chlorine inventory. Real time in situ observations of HCl can provide an important window into the complex photochemical reaction pathways for chlorine in the atmosphere, including heterogeneous reactions on aerosol surfaces. In this work, we report a novel, commercially-available HCl gas-phase analyzer (G2108, Picarro Inc. Santa Clara, CA, USA) based upon Cavity Ring Down Spectroscopy (CRDS) in the near-infrared, and discuss its performance. With a measurement interval of approximately 2 seconds, a precision of better than 40 parts-per-trillion (1 sigma, 30 seconds), and a response time of approximately 1-2 minutes (10 - 90% rise time or 90 - 10% fall time), this analyzer is well-suited for measurements of atmospherically-relevant concentrations of HCl, in both laboratory and field. CRDS provides very stable measurements and low drift, requiring infrequent calibration of the instrument, and can therefore be operated remotely for extended periods of time. In this work we also present results from a laboratory intercomparison of the Picarro G2108 analyzer and an iodide ion time-of-flight Chemical Ionization Mass Spectrometer (CIMS), and the results of the analyzer time response tests.

Transport and fate of organic wastes in groundwater at the Stringfellow hazardous waste disposal site, southern California

USGS Publications Warehouse

Leenheer, J.A.; Hsu, J.; Barber, L.B.

2001-01-01

In January 1999, wastewater influent and effluent from the pretreatment plant at the Stringfellow hazardous waste disposal site were sampled along with groundwater at six locations along the groundwater contaminant plume. The objectives of this sampling and study were to identify at the compound class level the unidentified 40-60% of wastewater organic contaminants, and to determine what organic compound classes were being removed by the wastewater pretreatment plant, and what organic compound classes persisted during subsurface waste migration. The unidentified organic wastes are primarily chlorinated aromatic sulfonic acids derived from wastes from DDT manufacture. Trace amounts of EDTA and NTA organic complexing agents were discovered along with carboxylate metabolites of the common alkylphenolpolyethoxylate plasticizers and nonionic surfactants. The wastewater pretreatment plant removed most of the aromatic chlorinated sulfonic acids that have hydrophobic neutral properties, but the p-chlorobenzenesulfonic acid which is the primary waste constituent passed through the pretreatment plant and was discharged in the treated wastewaters transported to an industrial sewer. During migration in groundwater, p-chlorobenzenesulfonic acid is removed by natural remediation processes. Wastewater organic contaminants have decreased 3- to 45-fold in the groundwater from 1985 to 1999 as a result of site remediation and natural remediation processes. The chlorinated aromatic sulfonic acids with hydrophobic neutral properties persist and have migrated into groundwater that underlies the adjacent residential community. Copyright ?? 2001 .

Five years experience of photodynamic therapy with new chlorin photosensitizer

NASA Astrophysics Data System (ADS)

Privalov, Valery A.; Lappa, Alexander V.; Kochneva, Elena V.

2005-08-01

Clinical results of photodynamic therapy (PDT) with a novel natural second generation chlorin-type photosensitizer "Radachlorin", mainly consisting of sodium chlorine e6, are presented. This sensitizer possesses a number of advantages over sensitizers of hematoporphyrin and phthalocyanine types. In particular, Radachlorin is excreted from organism much faster (in 1-2 days), as a result the problem of patient light hypersensitivity for a few months is non-actual for Radachlorin. As light source there was used a 662 nm diode laser specially designed for PDT with Radachlorin. The 5 year clinical results of PDT application to 89 patients with different malignant tumors are summarized and analysed. It is shown in particular that PDT with Radachlorin is a radical high efficient method for treatment of basal cell carcinoma of skin. At intravenous introduction in drug dose 0.5 mg/kg with light fluence 300-350 J/cm2 or in dose 1 mg/kg with fluence 200-250 J/cm2 the method gives full recovery in almost 100% cases with excellent cosmetic effect. The method was successfully combined with surgical operations, laser ablations, radio- and chemotherapy. Preoperative and intraoperative PDT favors improvement of results in complex treatment of malignant tumors. The method has a potential as palliative measure; in a number of incurable cases it allowed us to achieve recanalization of obturated hollow organs, eliminate the inflammatory complications, and as a result to improve life quality.

Assessment of In-Situ Reductive Dechlorination Using Compound-Specific Stable Isotopes, Functional-Gene Pcr, and Geochemical Data

PubMed Central

Carreón-Diazconti, Concepción; Santamaría, Johanna; Berkompas, Justin; Field, James A.; Brusseau, Mark L.

2010-01-01

Isotopic analysis and molecular-based bioassay methods were used in conjunction with geochemical data to assess intrinsic reductive dechlorination processes for a chlorinated-solvent contaminated site in Tucson, Arizona. Groundwater samples were obtained from monitoring wells within a contaminant plume comprising tetrachloroethene and its metabolites trichloroethene, cis-1,2-dichloroethene, vinyl chloride, and ethene, as well as compounds associated with free-phase diesel present at the site. Compound specific isotope (CSI) analysis was performed to characterize biotransformation processes influencing the transport and fate of the chlorinated contaminants. PCR analysis was used to assess the presence of indigenous reductive dechlorinators. The target regions employed were the 16s rRNA gene sequences of Dehalococcoides sp. and Desulfuromonas sp., and DNA sequences of genes pceA, tceA, bvcA, and vcrA, which encode reductive dehalogenases. The results of the analyses indicate that relevant microbial populations are present and that reductive dechlorination is presently occurring at the site. The results further show that potential degrader populations as well as biotransformation activity is non-uniformly distributed within the site. The results of laboratory microcosm studies conducted using groundwater collected from the field site confirmed the reductive dechlorination of tetrachloroethene to dichloroethene. This study illustrates the use of an integrated, multiple-method approach for assessing natural attenuation at a complex chlorinated-solvent contaminated site. PMID:19603638

Quantification of short- and medium-chain chlorinated paraffins in environmental samples by gas chromatography quadrupole time-of-flight mass spectrometry.

PubMed

Gao, Wei; Wu, Jing; Wang, Yawei; Jiang, Guibin

2016-06-24

Chlorinated paraffins (CPs) are technical products produced and used in bulk for a number of purposes. However, the analysis of CPs is challenging, as they are complex mixtures of compounds and isomers. We herein report the development of an analytical method for the analysis of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) using quadrupole time-of-flight high-resolution mass spectrometry (GC-NCI-qTOF-HRMS). This method employs gas chromatography with a chemical ionization source working in negative mode. The linear relationship between chlorination and the CP total response factors was applied to quantify the CP content and the congener group distribution patterns. In a single injection, 24 SCCP formula groups and 24 MCCP formula groups were quantified. Extraction of accurate masses using qTOF-HRMS allowed the SCCPs and MCCPs to be distinguished, with interference from other chemicals (e.g., PCBs) being largely avoided. The SCCP and MCCP detection limits were 24-81ng/mL and 27-170ng/mL, respectively. Comparison of the obtained results with analytical results from gas chromatography coupled with electron capture negative ionization low-resolution mass spectrometry (GC-ECNI-LRMS) indicate that the developed technique is a more accurate and convenient method for the analysis of CPs in samples from a range of matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

Distribution and trophic transfer of short-chain chlorinated paraffins in an aquatic ecosystem receiving effluents from a sewage treatment plant.

PubMed

Zeng, Lixi; Wang, Thanh; Wang, Pu; Liu, Qian; Han, Shanlong; Yuan, Bo; Zhu, Nali; Wang, Yawei; Jiang, Guibin

2011-07-01

Short-chain chlorinated paraffins (SCCPs) are an extremely complex group of industrial chemicals and found to be potential persistent organic pollutants (POPs), and thus have attracted extensive concern worldwide. In this study, influent, effluent, and sludge were collected from a large sewage treatment plant (STP) in Beijing, China. Water, sediment, and aquatic species were also collected from a recipient lake that receives effluents discharged from the STP. These samples were then analyzed to investigate the effect of STP effluent on distribution and trophic transfer of SCCPs in the local aquatic ecosystem. Concentrations of total SCCPs (ΣSCCPs) in lake water and surface sediments were found in the range 162-176 ng/L and 1.1-8.7 μg/g (dry weight, dw), respectively. Vertical concentration profiles of sediment cores showed ΣSCCPs decreased exponentially with increasing depth. Specific congener composition analysis in sediment layers indicated possible in situ biodegradation might be occurring. High bioaccumulation of SCCPs was observed in the sampled aquatic species. The bioaccumulation factor (BAF) generally increased with the number of chlorines in the SCCP congeners. A significantly positive correlation between lipid-normalized ΣSCCPs concentration and trophic levels (R(2) = 0.65, p < 0.05) indicate that SCCPs can biomagnify through the food chain in the effluent-receiving aquatic ecosystem.

Detection of Legionella, L. pneumophila and Mycobacterium avium complex (MAC) along potable water distribution pipelines.

PubMed

Whiley, Harriet; Keegan, Alexandra; Fallowfield, Howard; Bentham, Richard

2014-07-18

Inhalation of potable water presents a potential route of exposure to opportunistic pathogens and hence warrants significant public health concern. This study used qPCR to detect opportunistic pathogens Legionella spp., L. pneumophila and MAC at multiple points along two potable water distribution pipelines. One used chlorine disinfection and the other chloramine disinfection. Samples were collected four times over the year to provide seasonal variation and the chlorine or chloramine residual was measured during collection. Legionella spp., L. pneumophila and MAC were detected in both distribution systems throughout the year and were all detected at a maximum concentration of 103 copies/mL in the chlorine disinfected system and 106, 103 and 104 copies/mL respectively in the chloramine disinfected system. The concentrations of these opportunistic pathogens were primarily controlled throughout the distribution network through the maintenance of disinfection residuals. At a dead-end and when the disinfection residual was not maintained significant (p < 0.05) increases in concentration were observed when compared to the concentration measured closest to the processing plant in the same pipeline and sampling period. Total coliforms were not present in any water sample collected. This study demonstrates the ability of Legionella spp., L. pneumophila and MAC to survive the potable water disinfection process and highlights the need for greater measures to control these organisms along the distribution pipeline and at point of use.

Chlorine decay and bacterial inactivation kinetics in drinking water in the tropics.

PubMed

Thøgersen, J; Dahi, E

1996-09-01

The decay of free chlorine (Cl2) and combined chlorine (mostly monochloramine: NH2Cl) and the inactivation of bacteria was examined in Dar es Salaam, Tanzania. Batch experiments, pilot-scale pipe experiments and full-scale pipe experiments were carried out to establish the kinetics for both decay and inactivation, and to compare the two disinfectants for use under tropical conditions. The decay of both disinfectants closely followed first order kinetics, with respect to the concentration of both disinfectant and disinfectant-consuming substances. Bacterial densities exhibited a kinetic pattern consisting of first order inactivation with respect to the density of the bacteria and the concentration of the disinfectant, and first order growth with respect to the bacterial density. The disinfection kinetic model takes the decaying concentration of the disinfectant into account. The decay rate constant for free chlorine was 114 lg(-1)h(-1), while the decay rate constant for combined chlorine was 1.84 lg(-1)h(-1) (1.6% of the decay rate for free chlorine). The average concentration of disinfectant consuming substances in the water phase was 2.6 mg Cl2/l for free chlorine and 5.6 mg NH2Cl/l for combined chlorine. The decay rate constant and the concentration of disinfectant consuming substances when water was pumped through pipes, depended on whether or not chlorination was continuous. Combined chlorine especially could clean the pipes of disinfectant consuming substances. The inactivation rate constant λ, was estimated at 3.06×10(4) lg(-1)h(-1). Based on the inactivation rate constant, and a growth rate constant determined in a previous study, the critical concentration of free chlorine was found to be 0.08 mg Cl2/l. The critical concentration is a value below which growth rates dominate over inactivation.

Effects of assimilable organic carbon and free chlorine on bacterial growth in drinking water.

PubMed

Liu, Xiaolu; Wang, Jingqi; Liu, Tingting; Kong, Weiwen; He, Xiaoqing; Jin, Yi; Zhang, Bolin

2015-01-01

Assimilable organic carbon (AOC) is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM). The initial AOC concentration was 168 μg.L(-1) in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1 × 10(5) cells.mL(-1) to 2.6 × 10(4) cells.mL(-1) at an initial free chlorine dose of 0.6 mg.L(-1) to 4.8 × 10(4) cells.mL(-1) at an initial free chlorine dose of 0.3 mg.L(-1) due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network.

Effects of Assimilable Organic Carbon and Free Chlorine on Bacterial Growth in Drinking Water

PubMed Central

Liu, Tingting; Kong, Weiwen; He, Xiaoqing; Jin, Yi; Zhang, Bolin

2015-01-01

Assimilable organic carbon (AOC) is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM). The initial AOC concentration was 168 μg.L-1 in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1×105 cells.mL-1 to 2.6×104 cells.mL-1 at an initial free chlorine dose of 0.6 mg.L-1 to 4.8×104 cells.mL-1 at an initial free chlorine dose of 0.3 mg.L-1 due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network. PMID:26034988

Prechlorination of algae-laden water: The effects of transportation time on cell integrity, algal organic matter release, and chlorinated disinfection byproduct formation.

PubMed

Qi, Jing; Lan, Huachun; Liu, Ruiping; Miao, Shiyu; Liu, Huijuan; Qu, Jiuhui

2016-10-01

The prechlorination-induced algal organic matter (AOM) released from Microcystis aeruginosa (M. aeruginosa) cells has been reported to serve as a source of precursors for chlorinated disinfection byproducts (DBPs). However, previous studies have mainly focused on the precursors either extracted directly from the cell suspension or derived immediately after algal suspension prechlorination. This study aims to investigate the impacts of water transportation time after algal suspension prechlorination on cell integrity, AOM release, and DBP formation during the dissolved phase chlorination. The damage to cell integrity after prechlorination was indicated to depend not only on chlorine dose but also on transportation time. The highest dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) values were observed at 2 mg/L chlorine preoxidation before transportation, but were obtained at 0.4 mg/L chlorine after 480-min simulated transportation. The variation of DON with transportation time was indicated to be mainly influenced by the small molecular weight nitrogenous organic compounds, such as amino acids. Additionally, formation of the corresponding chlorinated carbonaceous disinfection byproducts (C-DBPs) and nitrogenous disinfection byproducts (N-DBPs) during the dissolved phase chlorination showed the same variation tendency as DOC and DON respectively. The highest C-DBP (98.4 μg/L) and N-DBP (5.5 μg/L) values were obtained at 0.4 mg/L chlorine preoxidation after 480-min simulated transportation. Therefore, when prechlorination is applied for algae-laden water pretreatment, not only chlorine dose but also transportation time needs to be considered with regard to their effects on cell integrity, AOM release, and chlorinated DBP formation. Copyright © 2016. Published by Elsevier Ltd.

Inhibition of chlorine-induced lung injury by the type 4 phosphodiesterase inhibitor rolipram

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Weiyuan; Chen, Jing; Schlueter, Connie F.

2012-09-01

Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole bodymore » exposure, 228–270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1 h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. -- Highlights: ► Chlorine causes lung injury when inhaled and is considered a chemical threat agent. ► Rolipram inhibited chlorine-induced pulmonary edema and airway hyperreactivity. ► Post-exposure rolipram treatments by both systemic and local delivery were effective. ► Rolipram shows promise as a rescue treatment for chlorine-induced lung injury.« less

Transformation pathways and acute toxicity variation of 4-hydroxyl benzophenone in chlorination disinfection process.

PubMed

Liu, Wei; Wei, Dongbin; Liu, Qi; Du, Yuguo

2016-07-01

Benzophenones compounds (BPs) are widely used as UV filters, and have been frequently found in multiple environmental matrices. The residual of BPs in water would cause potential threats on ecological safety and human health. Chlorination disinfection is necessary in water treatment process, in which many chemicals remained in water would react with disinfectant chlorine and form toxic by-products. By using ultra performance liquid phase chromatography quadrupole time of flight mass spectrometer (UPLC-QTOF-MS), nuclear magnetic resonance (NMR), the transformation of 4-hydroxyl benezophenone (4HB) with free available chlorine (FAC) was characterized. Eight major products were detected and seven of them were identified. Transformation pathways of 4HB under acid, neutral, and alkaline conditions were proposed respectively. The transformation mechanisms involved electrophilic chlorine substitution of 4HB, Baeyer-Villiger oxidation of ketones, hydrolysis of esters and oxidative breakage of benzene ring. The orthogonal experiments of pH and dosages of disinfectant chlorine were conducted. The results suggested that pH conditions determined the occurrence of reaction types, and the dosages of disinfectant chlorine affected the extent of reactions. Photobacterium assay demonstrated that acute toxicity had significant increase after chlorination disinfection of 4HB. It was proved that 3,5-dichloro-4HB, one of the major transformation products, was responsible for the increasing acute toxicity after chlorination. It is notable that, 4HB at low level in real ambient water matrices could be transformed during simulated chlorination disinfection practice. Especially, two major products 3-chloro-4HB and 3,5-dichloro-4HB were detected out, implying the potential ecological risk after chlorination disinfection of 4HB. Copyright © 2016 Elsevier Ltd. All rights reserved.

Persistent sub-lethal chlorine exposure augments temperature induced immunosuppression in Cyprinus carpio advanced fingerlings.

PubMed

Verma, A K; Pal, A K; Manush, S M; Das, T; Dalvi, R S; Chandrachoodan, P P; Ravi, P M; Apte, S K

2007-05-01

Apart from increased temperature, thermal effluents discharged through cooling systems of nuclear power plants may often contain chlorine (used against bio-fouling), which may affect the immune status of fish. Therefore, a 28-day trial was undertaken to delineate the effect of high temperature and a persistent sub-lethal chlorine exposure on immunomodulation in Cyprinus carpio advanced fingerlings. Fish were acclimated to four different temperatures (26, 31, 33 and 36 degrees C) and maintained for 30 days in two different groups. One group was exposed to persistent chlorine (0.1mgL(-1)) and was compared with their respective temperature control groups (without chlorine exposure). Expression of heat shock proteins (hsp 70) was tested in muscle after 28 days using Western blotting. Haematological parameters (erythrocyte count, leucocyte count, haemoglobin), serum parameters (total protein, albumin, globulin, A/G ratio) and respiratory burst activity were tested to assess immuno-competence of C. carpio in response to temperature and chlorine exposure. Results indicated that hsp 70 was induced at 36 degrees C in temperature control groups but not in their respective temperatures in the presence of chlorine. Haematological parameters such as haemoglobin, erythrocyte and leucocyte counts appeared depressed in chlorine treated groups as compared to their respective temperature control groups. Serum protein and globulin were affected due to chlorine exposure at different acclimation temperatures. A decrease in NBT activity was recorded in chlorine treated groups as compared to their respective temperature control groups. Overall results indicate that increasing acclimation temperatures alters the immune status of C. carpio advanced fingerlings and persistent sub-lethal exposure to chlorine augments this temperature induced immunosuppression.

Bromine-Chlorine Coupling in the Antarctic Ozone Hole

NASA Technical Reports Server (NTRS)

Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.; Prather, Michael J.

1996-01-01

The contribution from the chlorine and bromine species in the formation of the Antarctic ozone hole is evaluated. Since chlorine and bromine compounds are of different industrial origin, it is desirable, from a policy point of view, to be able to attribute chlorine-catalyzed loss of ozone with those reactions directly involving chlorine species, and likewise for bromine-catalyzed loss. In the stratosphere, however, most of the chemical families are highly coupled, and, for example, changes in the chlorine abundance will alter the partitioninig in other families and thus the rate of ozone loss. This modeling study examines formation of the Antarctic ozone hole for a wide range of bromine concentrations (5 - 25 pptv) and for chlorine concentrations typical of the last two decades (1.5, 2.5 and 3.5 ppbv). We follow the photochemical evolution of a single parcel of air, typical of the inner Antarctic vortex (50 mbar, 70 deg. S, NO(sub y) = 2 ppbv, with Polar Stratospheric Clouds(PSC)) from August 1 to November 1. For all of these ranges of chlorine and bromine loading, we would predict a substantial ozone hole (local depletion greater than 90%) within the de-nitrified, PSC- perturbed vortex. The contributions of the different catalytic cycles responsible for ozone loss are tabulated. The deep minimum in ozone is driven primarily by the chlorine abundance. As bromine levels decrease, the magnitude of the chlorine-catalyzed ozone loss increases to take up the slack. This is because bromine suppresses ClO by accelerating the conversion of ClO an Cl2O2 back to HCI. For this range of conditions, the local relative efficiency of ozone destruction per bromine atom to that per chlorine atom (alpha-factor) ranges from 33 to 55, decreasing with increase of bromine.

Secondary formation of disinfection by-products by UV treatment of swimming pool water.

PubMed

Spiliotopoulou, Aikaterini; Hansen, Kamilla M S; Andersen, Henrik R

2015-07-01

Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant effect on DBP formation was observed due to photo-inducible radical forming molecules NO3- (potentially present in high concentrations in pool water) and H2O2 (added as part of commercially employed DBP reducing practices). Copyright © 2015 Elsevier B.V. All rights reserved.

Factors affecting THMs, HAAs and HNMs formation of Jin Lan Reservoir water exposed to chlorine and monochloramine.

PubMed

Hong, Huachang; Xiong, Yujing; Ruan, Mengyong; Liao, Fanglei; Lin, Hongjun; Liang, Yan

2013-02-01

The formations of THMs, HAAs, and HNMs from chlorination and chloramination of water from Jinlan Reservoir were investigated in this study. Results showed that monochloramine rather than chlorine generally resulted in lower concentration of DBPs, and the DBPs formation varied greatly as the treatment conditions changed. Specifically, the yields of THMs, HAAs and HNMs all increased with the high bromide level and high disinfectant dose both during chlorination and chloramination. The longer reaction time had a positive effect on the formation of THMs, HAAs and HNMs during chlorination and HNMs during chloramination. However, no time effect was observed on the formation of THMs and HAAs during chloramination. An increase in pH enhanced the levels of THMs and HNMs upon chlorination but reduced levels of HNMs upon chloramination. As for the THMs in chloramination and HAAs in chlorination and chloramination, no obvious pH effect was observed. The elevated temperature significantly increased the yields of THMs during chlorination and HNMs during chloramination, but has no effect on THMs and HAAs yields during chloramination. In the same temperature range, the formation of HAAs and HNMs in chlorination showed a first increasing and then a decreasing trend. In chloramination study, addition of nitrite markedly increased the formation of HNMs but had little impact on the formation of THMs and HAAs. While in chlorination study, the presence of high nitrite levels significantly reduced the yields of THMs, HAAs and HNMs. Range analysis revealed that the bromide and disinfectant levels were the major factors affecting THMs, HAAs and HNMs formation, in both chlorination and chloramination. Finally, comparisons of the speciation of mono-halogenated, di-halogenated, tri-halogenated HAAs and HNMs between chlorination and monochloramination were also conducted, and factors influencing the speciation pattern were identified. Copyright © 2012 Elsevier B.V. All rights reserved.

Chemical additive to enhance antimicrobial efficacy of chlorine and control cross-contamination during immersion chill of broiler carcasses.

PubMed

Schambach, B T; Berrang, M E; Harrison, M A; Meinersmann, R J

2014-09-01

Immersion chilling of broiler carcasses can be a site for cross-contamination between the occasional highly contaminated carcass and those that are co-chilled. Chlorine is often used as an antimicrobial but can be overcome by organic material. A proprietary chlorine stabilizer (T-128) based on phosphoric acid-propylene glycol was tested as a chill tank additive in experiments simulating commercial broiler chilling. In bench-scale experiments, 0.5% T-128 was compared with plain water (control), 50 ppm of chlorine, and the combination of 0.5% T-128 with 50 ppm of chlorine to control transfer of Salmonella and Campylobacter from inoculated wing drummettes to co-chilled uninoculated drummettes. Both chlorine and T-128 lessened cross-contamination with Salmonella (P < 0.05); T-128 and T-128 with chlorine were significantly more effective (P < 0.05) than the control or plain chlorine for control of Campylobacter. T-128 treatments were noted to have a pH of less than 4.0; an additional experiment demonstrated that the antimicrobial effect of T-128 was not due merely to a lower pH. In commercial broiler chilling, a pH close to 6.0 is preferred to maximize chlorine effectiveness, while maintaining water-holding capacity of the meat. In a set of pilot-scale experiments with T-128, a near-ideal pH of 6.3 was achieved by using tap water instead of the distilled water used in bench-scale experiments. Pilot-scale chill tanks were used to compare the combination of 0.5% T-128 and 50 ppm of chlorine with 50 ppm of plain chlorine for control of cross-contamination between whole carcasses inoculated with Salmonella and Campylobacter and co-chilled uninoculated carcasses. The T-128 treatment resulted in significantly less crosscontamination by either direct contact or water transfer with both organisms compared with plain chlorine treatment. T-128 may have use in commercial broiler processing to enhance the effectiveness of chlorine in processing water.

Household Effectiveness vs. Laboratory Efficacy of Point-of-use Chlorination

PubMed Central

Levy, Karen; Anderson, Larissa; Robb, Katharine A.; Cevallos, William; Trueba, Gabriel; Eisenberg, Joseph N.S.

2014-01-01

Treatment of water at the household level offers a promising approach to combat the global burden of diarrheal diseases. In particular, chlorination of drinking water has been a widely promoted strategy due to persistence of residual chlorine after initial treatment. However, the degree to which chlorination can reduce microbial levels in a controlled setting (efficacy) or in a household setting (effectiveness) can vary as a function of chlorine characteristics, source water characteristics, and household conditions. To gain more understanding of these factors, we carried out an observational study within households in rural communities of northern coastal Ecuador. We found that the efficacy of chlorine treatment under controlled conditions was significantly better than its effectiveness when evaluated both by ability to meet microbiological safety standards and by log reductions. Water treated with chlorine achieved levels of microbial contamination considered safe for human consumption after 24 hours of storage in the household only 39 – 51% of the time, depending on chlorine treatment regimen. Chlorine treatment would not be considered protective against diarrheal disease according to WHO log reduction standards. Factors that explain the observed compromised effectiveness include: source water turbidity, source water baseline contamination levels, and in-home contamination. Water in 38% of the households that had low turbidity source water (< 10 NTU) met the safe water standard as compared with only 17% of the households that had high turbidity source water (> 10 NTU). A 10 MPN/100mL increase in baseline E. coli levels was associated with a 2.2% increase in failure to meet the E. colistandard. Higher mean microbial contamination levels in 54% of household samples in comparison to their matched controls, which is likely the result of in-home contamination during storage. Container characteristics (size of the container mouth) did not influence chlorine effectiveness. We found no significant differences between chlorine treatment regimens in ability to meet the safe water standards or in overall log reductions, although chlorine dosage did modify the effect of source conditions. These results underscore the importance of measuring both source water and household conditions to determine appropriate chlorine levels, as well as to evaluate the appropriateness of chlorine treatment and other point-of-use water quality improvement interventions. PMID:24561887

Household effectiveness vs. laboratory efficacy of point-of-use chlorination.

PubMed

Levy, Karen; Anderson, Larissa; Robb, Katharine A; Cevallos, William; Trueba, Gabriel; Eisenberg, Joseph N S

2014-05-01

Treatment of water at the household level offers a promising approach to combat the global burden of diarrheal diseases. In particular, chlorination of drinking water has been a widely promoted strategy due to persistence of residual chlorine after initial treatment. However, the degree to which chlorination can reduce microbial levels in a controlled setting (efficacy) or in a household setting (effectiveness) can vary as a function of chlorine characteristics, source water characteristics, and household conditions. To gain more understanding of these factors, we carried out an observational study within households in rural communities of northern coastal Ecuador. We found that the efficacy of chlorine treatment under controlled conditions was significantly better than its household effectiveness when evaluated both by ability to meet microbiological safety standards and by log reductions. Water treated with chlorine achieved levels of microbial contamination considered safe for human consumption after 24 h of storage in the household only 39-51% of the time, depending on chlorine treatment regimen. Chlorine treatment would not be considered protective against diarrheal disease according to WHO log reduction standards. Factors that explain the observed compromised effectiveness include: source water turbidity, source water baseline contamination levels, and in-home contamination. Water in 38% of the households that had low turbidity source water (<10 NTU) met the safe water standard as compared with only 17% of the households that had high turbidity source water (>10 NTU). A 10 MPN/100 mL increase in baseline Escherichia coli levels was associated with a 2.2% increase in failure to meet the E. coli standard. Higher mean microbial contamination levels were seen in 54% of household samples in comparison to their matched controls, which is likely the result of in-home contamination during storage. Container characteristics (size of the container mouth) did not influence chlorine effectiveness. We found no significant differences between chlorine treatment regimens in ability to meet the safe water standards or in overall log reductions, although chlorine dosage did modify the effect of source conditions. These results underscore the importance of measuring both source water and household conditions to determine appropriate chlorine levels, as well as to evaluate the appropriateness of chlorine treatment and other point-of-use water quality improvement interventions. Copyright © 2014 Elsevier Ltd. All rights reserved.

GENE EXPRESSION ALTERATIONS OBSERVED IN PRIMARY CULTURED RAT HEPATOCYTES AFTER TREATMENT WITH CHLORINATED OR CHLORINATED AND OZONATED DRINKING WATER FROM EAST FORK LAKE, OHIO

EPA Science Inventory

Drinking water from East Fork Lake was spiked with iodide and bromide, disinfected with chlorine or ozone + chlorine, concentrated ~100-fold using reverse osmosis, and volatile disinfection by-products (DBPs) added back. Primary rat hepatocytes were exposed to full-strength, 1:10...

40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system must...

40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system must...

40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system must...

40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system must...

Wastewater Treatment Evaluation, Mather AFB, CA

DTIC Science & Technology

1974-06-01

conveyed to the treatment facility is provided with secondary (biological) treatment and chlorination followed by polish- ing lagoons prior to bang...comminutor. b. Primary sedimentation (clarifier). c. Biological oxidation by trickling filter. d. Secondary sedimentation (clarifier). e. Chlorination . f...the entrance to the chlorine contact chamber. Following chlorination , the wastewater flows to the wet well of the effluent lift station from

Microscale Chemistry in a Plastic Petri Dish: Preparation and Chemical Properties of Chlorine Gas

NASA Astrophysics Data System (ADS)

Choi, Martin M. F.

2002-08-01

This experiment demonstrates some of the chemistry of chlorine on a microscale, about the size of a water droplet. Chlorine gas was prepared from an acidified bleach solution in a plastic petri dish. The chlorine gas generated in situ reacted with other chemical reagents in the dish by diffusion. Some of the oxidizing properties and bleaching power of chlorine gas were shown visually and could be observed within 10 minutes. These experiments provide suitable hands-on experience for students at secondary-school level.

A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

PubMed Central

Taylor, G. R.; Butler, M.

1982-01-01

Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the other disinfectants were able to inactivate poliovirus without causing any apparent structural changes. Images Plate 1 PMID:6290566

A study on recovery of uranium in the anode basket residues delivered from the pyrochemical process of used nuclear fuel

NASA Astrophysics Data System (ADS)

Eun, H. C.; Kim, T. J.; Jang, J. H.; Kim, G. Y.; Park, S. B.; Yoon, D. S.; Kim, S. H.; Paek, S. W.; Lee, S. J.

2018-04-01

In this study, the chlorination of uranium oxide (UO2) using ammonium chloride and zirconium as chemical agents was conducted to recover the uranium in the anode basket residues from the pyrochemical process of used nuclear fuel. The chlorination of UO2 was predicted using thermodynamic equilibrium calculations. The experimental conditions for the chlorination were determined using a chlorination test with cerium oxide (CeO2). In the chlorination test, it was confirmed that UO2 was chlorinated into UCl3 at 320 °C, some UO2 remained without changes in the chemical form, and ZrO2, Zr2O, and ZrCl2 were generated as byproducts.

Evaluation of the fate and transport of chlorinated ethenes in a complex groundwater system discharging to a stream in Wonju, Korea.

PubMed

Lee, Seong-Sun; Kaown, Dugin; Lee, Kang-Kun

2015-11-01

Chlorinated ethenes such as trichloroethylene (TCE) are common and persistent groundwater contaminants. If contaminated groundwater discharges to a stream, then stream water pollution near the contamination site also becomes a problem. In this respect, the fate and transport of chlorinated ethenes around a stream in an industrial complex were evaluated using the concentration of each component, and hydrogeochemical, microbial, and compound-specific carbon isotope data. Temporal and spatial monitoring reveal that a TCE plume originating from main and local source zones continues to be discharged to a stream. Groundwater geochemical data indicate that aerobic conditions prevail in the upgradient area of the studied aquifer, whereas conditions become anaerobic in the downgradient. The TCE molar fraction is high at the main and local source zones, ranging from 87.4 to 99.2% of the total volatile organic compounds (VOCs). An increasing trend in the molar fraction of cis-1, 2-Dichloroethene (cis-DCE) and vinyl chloride (VC) was observed in the downgradient zone of the study area. The enriched δ(13)C values of TCE and depleted values of cis-DCE in the stream zone, compared to those of the source zone, also suggest biodegradation of VOCs. Microbial community structures in monitoring wells adjacent to the stream zone in the downgradient area were analyzed using 16S rRNA gene-based pyrosequencing to identify the microorganisms responsible for biodegradation. This was attributed to the high relative abundance of dechlorinating bacteria in monitoring wells under anaerobic conditions farthest from the stream in the downgradient area. The multilateral approaches adopted in this study, combining hydrogeochemical and biomolecular methods with compound-specific analyses, indicate that contaminants around the stream were naturally attenuated by active anaerobic biotransformation processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Chem 13 News Digest

ERIC Educational Resources Information Center

Friesen, R. J., Ed.

1975-01-01

Discusses the chlorination of water supplies. Includes a description of the chemical species present due to chlorination, and the dangers of and alternatives to the chlorination of water systems. (MLH)

A Review Study on Macrolides Isolated from Cyanobacteria.

PubMed

Wang, Mengchuan; Zhang, Jinrong; He, Shan; Yan, Xiaojun

2017-04-26

Cyanobacteria are rich sources of structurally-diverse molecules with promising pharmacological activities. Marine cyanobacteria have been proven to be true producers of some significant bioactive metabolites from marine invertebrates. Macrolides are a class of bioactive compounds isolated from marine organisms, including marine microorganisms in particular. The structural characteristics of macrolides from cyanobacteria mainly manifest in the diversity of carbon skeletons, complexes of chlorinated thiazole-containing molecules and complex spatial configuration. In the present work, we systematically reviewed the structures and pharmacological activities of macrolides from cyanobacteria. Our data would help establish an effective support system for the discovery and development of cyanobacterium-derived macrolides.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jing; Mo, Yiqun; Schlueter, Connie F.

Chlorine gas is a widely used industrial compound that is highly toxic by inhalation and is considered a chemical threat agent. Inhalation of high levels of chlorine results in acute lung injury characterized by pneumonitis, pulmonary edema, and decrements in lung function. Because inflammatory processes can promote damage in the injured lung, anti-inflammatory therapy may be of potential benefit for treating chemical-induced acute lung injury. We previously developed a chlorine inhalation model in which mice develop epithelial injury, neutrophilic inflammation, pulmonary edema, and impaired pulmonary function. This model was used to evaluate nine corticosteroids for the ability to inhibit chlorine-inducedmore » neutrophilic inflammation. Two of the most potent corticosteroids in this assay, mometasone and budesonide, were investigated further. Mometasone or budesonide administered intraperitoneally 1 h after chlorine inhalation caused a dose-dependent inhibition of neutrophil influx in lung tissue sections and in the number of neutrophils in lung lavage fluid. Budesonide, but not mometasone, reduced the levels of the neutrophil attractant CXCL1 in lavage fluid 6 h after exposure. Mometasone or budesonide also significantly inhibited pulmonary edema assessed 1 day after chlorine exposure. Chlorine inhalation resulted in airway hyperreactivity to inhaled methacholine, but neither mometasone nor budesonide significantly affected this parameter. The results suggest that mometasone and budesonide may represent potential treatments for chemical-induced lung injury. - Highlights: • Chlorine causes lung injury when inhaled and is considered a chemical threat agent. • Corticosteroids may inhibit lung injury through their anti-inflammatory actions. • Corticosteroids inhibited chlorine-induced pneumonitis and pulmonary edema. • Mometasone and budesonide are potential rescue treatments for chlorine lung injury.« less

Cometabolic degradation of chlorinated alkenes by alkene monooxygenase in a propylene-grown Xanthobacter strain.

PubMed Central

Ensign, S A; Hyman, M R; Arp, D J

1992-01-01

Propylene-grown Xanthobacter cells (strain Py2) degraded several chlorinated alkenes of environmental concern, including trichloroethylene, 1-chloroethylene (vinyl chloride), cis- and trans-1,2-dichloroethylene, 1,3-dichloropropylene, and 2,3-dichloropropylene. 1,1-Dichloroethylene was not degraded efficiently, while tetrachloroethylene was not degraded. The role of alkene monooxygenase in catalyzing chlorinated alkene degradations was established by demonstrating that glucose-grown cells which lack alkene monooxygenase and propylene-grown cells in which alkene monooxygenase was selectively inactivated by propyne were unable to degrade the compounds. C2 and C3 chlorinated alkanes were not oxidized by alkene monooxygenase, but a number of these compounds were inhibitors of propylene and ethylene oxidation, suggesting that they compete for binding to the enzyme. A number of metabolites enhanced the rate of degradation of chlorinated alkenes, including propylene oxide, propionaldehyde, and glucose. Propylene stimulated chlorinated alkene oxidation slightly when present at a low concentration but became inhibitory at higher concentrations. Toxic effects associated with chlorinated alkene oxidations were determined by measuring the propylene oxidation and propylene oxide-dependent O2 uptake rates of cells previously incubated with chlorinated alkenes. Compounds which were substrates for alkene monooxygenase exhibited various levels of toxicity, with 1,1-dichloroethylene and trichloroethylene being the most potent inactivators of propylene oxidation and 1,3- and 2,3-dichloropropylene being the most potent inactivators of propylene oxide-dependent O2 uptake. No toxic effects were seen when cells were incubated with chlorinated alkenes anaerobically, indicating that the product(s) of chlorinated alkene oxidation mediates toxicity. PMID:1444418

Mass Spectrometry Identification of N-Chlorinated Dipeptides in Drinking Water.

PubMed

Huang, Guang; Jiang, Ping; Li, Xing-Fang

2017-04-04

We report the identification of N-chlorinated dipeptides as chlorination products in drinking water using complementary high-resolution quadrupole time-of-flight (QTOF) and quadrupole ion-trap mass spectrometry techniques. First, three model dipeptides, tyrosylglycine (Tyr-Gly), tyrosylalanine (Tyr-Ala), and phenylalanylglycine (Phe-Gly), reacted with sodium hypochlorite, and these reaction solutions were analyzed by QTOF. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N,N-di-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala were identified as the major products based on accurate masses, 35 Cl/ 37 Cl isotopic patterns, and MS/MS spectra. These identified N-chlorinated dipeptides were synthesized and found to be stable in water over 10 days except N,N-di-Cl-Phe-Gly. To enable sensitive detection of N-chlorinated dipeptides in authentic water, we developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with multiple reaction monitoring (MRM) mode. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala along with their corresponding dipeptides were detected in authentic tap water samples. The dipeptides were clearly detected in the raw water, but the N-chlorinated dipeptides were at background levels. These results suggest that the N-chlorinated dipeptides are produced by chlorination. This study has identified N-chlorinated dipeptides as new disinfection byproducts in drinking water. The strategy developed in this study can be used to identify chlorination products of other peptides in drinking water.

Inactivation of Renibacterium salmoninarum by free chlorine

USGS Publications Warehouse

Pascho, Ronald J.; Landolt, Marsha L.; Ongerth, Jerry E.

1995-01-01

Salmonid fishes contract bacterial kidney disease by vertical or horizontal transmission of the pathogenic bacterium, Renibacterium salmoninarum. Procedures to reduce vertical transmission are under evaluation, but methods are still needed to eliminate sources of waterborne R. salmoninarum. We examined the efficacy of chlorine to inactivate R. salmoninarum. The bacterium was exposed to various levels of chlorine at pH 6, 7, or 8, and at 7.5 °C or 15 °C. At pH 7 and 15 °C, 99% inactivation occurred within 18 s, even at free chlorine concentrations as low as 0.05 mg/l. Chlorine was most effective at neutral or acidic pH, and 15 °C. The inactivation curves for 7.5 °C and pH 7, or 15 °C and pH 8, deviated from first-order kinetics by exhibiting shoulders or a tailing-off effect, suggesting that chlorine and the bacterial cells were not the sole reactants. A plot of the concentration-time (Ct) products for free chlorine at pH 7 and 15 °C produced a line with a slope less than 1, indicating that the duration of exposure was more important than the concentration of free chlorine. These data indicate that R. salmoninarum is very sensitive to chlorine, and that this disinfectant may be appropriate for use in fish hatcheries rearing salmonids affected by bacterial kidney disease.

Effect of chlorine, blanching, freezing, and microwave heating on Cryptosporidium parvum viability inoculated on green peppers.

PubMed

Duhain, G L M C; Minnaar, A; Buys, E M

2012-05-01

Cryptosporidium parvum oocysts have been found on the surface of vegetables in both developed and developing countries. C. parvum can contaminate vegetables via various routes, including irrigation water. This study investigated the effect of individual treatments of chlorine, blanching, blast freezing, and microwave heating, as well as combined treatments of chlorine and freezing, and chlorine and microwave heating on the viability of C. parvum oocysts inoculated on green peppers. The viability of the oocysts after the treatments was assessed using propidium iodide and a flow cytometer. Based on the propidium iodide staining, the chlorine treatments did not affect the viability of the oocysts. Blast freezing significantly inactivated 20% of the oocysts. Microwave heating and blanching significantly inactivated 93% of oocysts. Treatment with chlorine followed by blast freezing did not affect the viability of the oocysts significantly. Treatment with chlorine and microwave heating was significantly more effective than microwave heating alone and inactivated 98% of the oocysts. The study indicates that C. parvum oocysts are sensitive to heat and, to some extent, to blast freezing, but are resistant to chlorine. Therefore, the use of chlorine during vegetable processing is not a critical control point for C. parvum oocysts, and the consumption of raw or minimally processed vegetables may constitute a health risk as C. parvum oocysts can still be found viable on ready-to-eat, minimally processed vegetables.

CHEMICAL AND TOXICOLOGICAL EVALUATION OF CHLORINATED AND OZONATED-CHLORINATED DRINKING WATER: A COLLABORATION OF THE FOUR NATIONAL LABS OF THE U. S. EPA

EPA Science Inventory

CHEMICAL AND TOXICOLOGICAL EVALUATION OF CHLORINATED AND OZONATED-CHLORINATED DRINKING WATER: A COLLABORATION OF THE FOUR NATIONAL LABS OF THE U.S. EPA
Susan D. Richardson1, Linda K. Teuschler2, Alfred D. Thruston, Jr.,1 Thomas Speth3, Richard J. Miltner3, Glenn Rice2, Kathle...

Investigation Of Ballast Water Treatment’s Effect On Corrosion

DTIC Science & Technology

2013-03-01

Lysogorski, et al | Public March 2013 N O T I C E This document is disseminated under the sponsorship of the Department of Homeland...Controlled laboratory tests were conducted using simulated chlorination, deoxygenation and chlorine dioxide disinfection . Materials were exposed to three...Great Lakes water simulated chlorination, deoxygenation, and chlorine dioxide disinfection . All testing was conducted at NRLKW. Natural, unfiltered

Disinfecting capabilities of oxychlorine compounds.

PubMed Central

Noss, C I; Olivieri, V P

1985-01-01

The bacterial virus f2 was inactivated by chlorine dioxide at acidic, neutral, and alkaline pH values. The rate of inactivation increased with increasing pH. Chlorine dioxide disproportionation products, chlorite and chlorate, were not active disinfectants. As chlorine dioxide solutions were degraded under alkaline conditions, they displayed reduced viricidal effectiveness, thereby confirming the chlorine dioxide free radical as the active disinfecting species. PMID:3911893

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Leo H. H.; Hoque, Enamul; Kruse, Peter

Free chlorine from dissolved chlorine gas is widely used as a disinfectant for drinking water. The residual chlorine concentration has to be continuously monitored and accurately controlled in a certain range around 0.5–2 mg/l to ensure drinking water safety and quality. However, simple, reliable, and reagent free monitoring devices are currently not available. Here, we present a free chlorine sensor that uses oxidation of a phenyl-capped aniline tetramer (PCAT) to dope single wall carbon nanotubes (SWCNTs) and to change their resistance. The oxidation of PCAT by chlorine switches the PCAT-SWCNT system into a low resistance (p-doped) state which can be detectedmore » by probing it with a small voltage. The change in resistance is found to be proportional to the log-scale concentration of the free chlorine in the sample. The p-doping of the PCAT-SWCNT film then can be electrochemically reversed by polarizing it cathodically. This sensor not only shows good sensing response in the whole concentration range of free chlorine in drinking water but is also able to be electrochemically reset back many times without the use of any reagents. This simple sensor is ideally suited for measuring free chlorine in drinking water continuously.« less

Combined toxicity effects of chlorine, ammonia, and temperature on marine plankton. Progress report, September 16, 1975--September 30, 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldman, J. C.; Ryther, J. H.

1976-10-01

Research on the combined effects of chlorine, ammmonia and temperature on marine plankton have been carried out for 20 months. To date continuous-flow bioassays have been conducted on lobster larvae (Homarus americanus), oyster larvae (Crassostrea virginica), copepods (Acartia tonsa), rotifers (Brachionus plicatilis), three juvenile and larval fish, killifish (Fundulus heteroclitus), scup (Stenotomus versicolor), and winter flounder (Pseudopleuronectes americanus), and phytoplankton (the diatom Phaeodactylum tricornutum). In addition, studies on zooplankton metabolism, filtration rates, and growth were carried out on exposed organisms. In general, the responses of invertebrates were distinctly different than those of fish: increasing mortality with increasing chlorine dose andmore » greater sensitivity to chloramines than free chlorine in the former, and a threshold level of chlorine and greater sensitivity to free chlorine in the latter. Phytoplankton responses indicate that chlorine effects on primary producers are minimal compared to the serious effects on zooplankton, particularly larval forms that spawn intermittently. The overall conclusion of our studies is that chlorine application at power plants must be carried out with extreme caution and that serious consideration should be given to applying dechlorination at all coastal cooling systems.« less

The occurrence of chlorine in serpentine minerals

USGS Publications Warehouse

Miura, Y.; Rucklidge, J.; Nord, G.L.

1981-01-01

Partially serpentinized dunites containing small amounts of Chlorine (< 0.5%) from Dumont, Quebec, and Horoman, Hokkaido, Japan, and one containing less than 0.05% Chlorine from Higashi-Akaishi-Yama, Ehime, Japan have been examined using the electron probe microanalyzer and scanning transmission electron microscope with X-ray analytical capabilities. Chlorine was found together with Si, Mg, Ca and Fe in the serpentine minerals of the Dumont and Hokkaido dunites but not in the Ehime dunite. Chlorine is found associated only with the most finely crystalline facies of the serpentine (grain size less than 10 nm). The Ehime dunite contained no such fine grained serpentine, and was thus effectively chlorine-free, as are the coarser grained serpentines of the other samples. The finegrained chlorine-bearing serpentine also has a much higher concentration of Fe, and can contain smaller amounts of Ca, Ni and Mn than the coarse-grained variety as well as minute awaruite (FeNi3) grains. This fine-grained serpentine probably represents an early stage in the transformation of olivine to serpentine, with chlorine from hydrothermal solutions assisting the necessary chemical changes. The Cl increases the reaction rate by lowering the activation barrier to reaction by the introduction of reaction steps. ?? 1981 Springer-Verlag.

Multi-species biofilms defined from drinking water microorganisms provide increased protection against chlorine disinfection.

PubMed

Schwering, Monika; Song, Joanna; Louie, Marie; Turner, Raymond J; Ceri, Howard

2013-09-01

A model biofilm, formed of multiple species from environmental drinking water, including opportunistic pathogens, was created to explore the tolerance of multi-species biofilms to chlorine levels typical of water-distribution systems. All species, when grown planktonically, were killed by concentrations of chlorine within the World Health Organization guidelines (0.2-5.0 mg l(-1)). Higher concentrations (1.6-40-fold) of chlorine were required to eradicate biofilm populations of these strains, ~70% of biofilms tested were not eradicated by 5.0 mg l(-1) chlorine. Pathogenic bacteria within the model multi-species biofilms had an even more substantial increase in chlorine tolerance; on average ~700-1100 mg l(-1) chlorine was required to eliminate pathogens from the biofilm, 50-300-fold higher than for biofilms comprising single species. Confocal laser scanning microscopy of biofilms showed distinct 3D structures and multiple cell morphologies and arrangements. Overall, this study showed a substantial increase in the chlorine tolerance of individual species with co-colonization in a multi-species biofilm that was far beyond that expected as a result of biofilm growth on its own.

[Toxicity and influencing factors of liquid chlorine on chironomid larvae].

PubMed

Sun, Xing-Bin; Cui, Fu-Yi; Zhang, Jin-Song; Guo, Zhao-Hai; Xu, Feng; Liu, Li-Jun

2005-09-01

The excessive propagation of Chironomid larvae (red worm) in the sedimentation tanks is a difficult problem for the normal function of waterworks. The toxic effect of liquid chlorine on the different instar larvae of Chironomid was studied using distilled water as test sample. Furthermore, the effect of pH value, organic matter content, ammonia nitrogen, and algae content on toxicity of liquid chlorine was observed. The results show that the tolerance of Chironomid larvae to liquid chlorine is strengthened with the increase in instar. The 24h semi-lethal concentration (LC50) of liquid chlorine to the 4th instar larvae of Chironomid is 3.39 mg/L. Low pH value and high algae content are helpful to improve the toxic effect of liquid chlorine to Chironomid larvae. In neutral water body, the increase in organic matter content results in the decrease in the death rate of Chironomid larvae. The toxicity of liquid chlorine differs greatly in different concentrations of ammonia nitrogen. The death rate of the 4th instar larvae of Chironomid in raw water is higher by contrast with that in sedimentation tanks water for 24h disposal with various amount of liquid chlorine.

General Approach to the Synthesis of the Chlorosulfolipids Danicalipin A, Mytilipin A, and Malhamensilipin A in Enantioenriched Form

PubMed Central

2015-01-01

A second-generation synthesis of three structurally related chlorosulfolipids has been developed. Key advances include highly stereocontrolled additions to α,β-dichloroaldehydes, kinetic resolutions of complex chlorinated vinyl epoxide intermediates, and Z-selective alkene cross metatheses of cis-vinyl epoxides. This strategy facilitated the synthesis of enantioenriched danicalipin A, mytilipin A, and malhamensilipin A in nine, eight, and 11 steps, respectively. PMID:24494597

Chlorine disinfection of grey water for reuse: effect of organics and particles.

PubMed

Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

2008-01-01

Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

Occurrence of by-products of strong oxidants reacting with drinking water contaminants--scope of the problem.

PubMed Central

Rice, R G; Gomez-Taylor, M

1986-01-01

This paper describes results of a detailed literature review of the organic and inorganic by-products that have been identified as being formed in aqueous solution with four of the strong oxidizing/disinfecting agents commonly employed in drinking water treatment. These agents are: chlorine, chlorine dioxide, chloramine, and ozone. Significant findings include the production of similar nonchlorinated organic oxidation products from chlorine, chlorine dioxide, and ozone. In addition, all three chlorinous oxidants/disinfectants can produce chlorinated by-products under certain conditions. The presence of chloronitrile compounds in drinking waters is indicated to arise from reactions of chlorine or chloramine to amine/amide functions in amino acids or proteinaceous materials, followed by dehydrohalogenation. These nitriles could hydrolyze to produce the corresponding chloroacetic acids. It is concluded that to minimize the presence of oxidation by-products in drinking waters, the concentrations of oxidizable organic/inorganic impurities should be lowered before any oxidizing agent is added. PMID:3545807

Exposure to chlorine dioxide gas for 4 hours renders Syphacia ova nonviable.

PubMed

Czarra, Jane A; Adams, Joleen K; Carter, Christopher L; Hill, William A; Coan, Patricia N

2014-07-01

The purpose of our study was to evaluate the efficacy of chlorine dioxide gas for environmental decontamination of Syphacia spp. ova. We collected Syphacia ova by perianal cellophane tape impression of pinworm-infected mice. Tapes with attached ova were exposed to chlorine dioxide gas for 1, 2, 3, or 4 h. After gas exposure, ova were incubated in hatching medium for 6 h to promote hatching. For controls, tapes with attached ova were maintained at room temperature for 1, 2, 3, and 4 h without exposure to chlorine dioxide gas and similarly incubated in hatch medium for 6 h. Ova viability after incubation was assessed by microscopic examination. Exposure to chlorine dioxide gas for 4 h rendered 100% of Syphacia spp. ova nonviable. Conversely, only 17% of ova on the 4-h control slide were nonviable. Other times of exposure to chlorine dioxide gas resulted in variable effectiveness. These data suggest that exposure to chlorine dioxide gas for at least 4 h is effective for surface decontamination of Syphacia spp. ova.

Screening of short- and medium-chain chlorinated paraffins in selected riverine sediments and sludge from the Czech Republic.

PubMed

Pribylová, Petra; Klánová, Jana; Holoubek, Ivan

2006-11-01

Wide distribution of chlorinated paraffins in the environment has already been demonstrated in several studies; however, information about their levels in the Central Europe is still very limited. First study focused on the SCCP contamination of the Czech aquatic environment have been performed recently, and its results motivated the authors to analyze sediments from a wide set of the Czech rivers in order to obtain more detailed information. Thirty-six sediment samples from eleven rivers and five drainage vents neighboring the chemical factories were analyzed; special attention was paid to the industrial areas. For the first time in the Czech Republic, medium-chain in addition to short-chain chlorinated paraffins were analyzed using GC-ECNI-MS. Chlorinated paraffins were detected in sediment samples on the concentration levels up to 347 ngg(-1) for short-chain chlorinated paraffins, and 5575 ngg(-1) for medium-chain chlorinated paraffins. Average chlorination degree of SCCPs was 65%.

Chlorine-36 and chlorine concentrations within several compartments of a deciduous forest ecosystem in Meuse/Haute-Marne (France)

NASA Astrophysics Data System (ADS)

Pupier, Julie; Benedetti, Lucilla; Bourles, Didier; Leclerc, Elisabeth; Thiry, Yves

2013-04-01

Chlorine-36 is a cosmogenic nuclide mainly produced in the atmosphere by interactions between energetic particles originating from the cosmic radiations and 40Ar. Because of its long half-life (T1-2 = 3.01 105 yr) and its high mobility, chlorine-36 is a critical radionuclide concerning radioactive waste repository sites. Moreover, it has been shown that inorganic chlorine could be enriched along the trophic chain due to its high solubility and bioavailability (Ashworth and Shaw, 2006). Additionally, many studies during the last decades have established that due to chlorination process, organic chlorine may account for a large proportion of the total soil chlorine pool (more than 80 % in surface soils of temperate ecosystems. Redon et al., 2012). The aim of this study is thus to measure chlorine-36 in all the compartments of the biogeochemical cycle, to better understand its recycling in the biosphere. The study site is the experimental beech forest site of the Andra long-term monitoring and testing system (OPE*). It is located at Montiers-sur-Saulx, North-East of France and is associated to the future radioactive waste repository site of Bure. Since March 2012, rainwater above (rainfall collected from a 45 m high tower built on purpose) and below (throughfall and stemflow) the canopy, has been collected monthly, as well as soil solutions (gravitational and bound waters) at four depths (0, 10, 30, 60 cm deep). Chlorine-36 and chlorine have been measured in the rainfall samples between March and July 2012 and in water solutions collected from all compartments of the biosphere using isotope dilution mass spectrometry at the french AMS national facility ASTER located at CEREGE. The results yielded from the rainfall samples allow to study the temporal fluctuations of chlorine-36 in the atmosphere, which represents the main inflow of chlorine-36 in its biogeochemical cycle. The first results indicate a flow increase during the late spring-early summer. Santos et al., 2004 have also observed a similar pattern in southern Spain. This increase might be due to a tropopause break, a natural process which occurs in spring and in fall. This break implies an increase of the air masses exchange between the tropopause and the stratosphere and therefore could cause high chlorine-36 inflow. All together, those results allow to draw a profile of the evolution of chlorine-36 concentrations in the various pools of the biogeochemical cycle (from the upper rainfall through stemflow and throughfall to the lower soil). Both 36Cl and Cl concentrations in stemflow samples are 25-50% higher than in the rainfall and throughfall samples. In water solutions collected from the soil, chlorine-36 concentrations vary between 3 to 8 10 3 at/ml, with an increase in the concentration at 30 cm depth. To understand the chlorine-36 recycling in soil, the next step will be to isolate and measure the 36Cl concentrations in the inorganic and organic fractions of chlorine in a soil profile. * : OPE : Observatoire Pérenne de l'Environnement (SOERE), French national long-term monitoring and experimental system for research in environment, www.andra-ope.fr Ashworth, D. J. and Shaw, G. (2006). A comparison of the soil migration and plant uptake of radioactive chlorine and iodine from contaminated groundwater. Journal of environmental radioactivity, 89(1) :61-80. Redon, P.-O., Jolivet, C., Saby, N. P. a., Abdelouas, A., and Thiry, Y. (2012). Occurrence of natural organic chlorine in soils for different land uses. Biogeochemistry (In press), doi : 10.1007/s10533- 012-9771-7. Santos, F., Lopez-Gutierrez, J., Garcia-Leon, M., Schnabel, C., Synal, H., and Suter, M. (2004). Analysis of 36Cl in atmospheric samples from Seville (Spain) by AMS. Nuclear Instruments and Methods in Physics Research Section B : Beam Interactions with Materials and Atoms, 223-224 :501-506.

Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

PubMed

Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

2013-01-14

A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

Iridoid glucosides from the aerial parts of Globularia alypum L. (Globulariaceae).

PubMed

Es-Safi, Nour-Eddine; Khlifi, Samira; Kollmann, Albert; Kerhoas, Lucien; El Abbouyi, Ahmed; Ducrot, Paul-Henri

2006-01-01

From the hydromethanolic extract of the aerial parts of Globularia alypum grown in Morocco, a new chlorinated iridoid glucoside, globularioside has been isolated beside 5 known iridoid glycosides, globularin, globularicisin, globularidin, globularinin and globularimin. This is the first report of a chlorinated iridoid in G. alypum and in the Globulareaceae. Unlike all other known 7-chlorinated iridoid glucosides where the chlorine atom exhibits an alpha configuration, globularioside incorporate the chlorine atom as a 7beta substituent. The structures of the isolated compounds were established on the basis of ESI-MS, MS-MS, 1D and 2D NMR spectral analysis.

Diurnal variation of stratospheric chlorine monoxide - A critical test of chlorine chemistry in the ozone layer

NASA Technical Reports Server (NTRS)

Solomon, P. M.; De Zafra, R.; Parrish, A.; Barrett, J. W.

1984-01-01

Ground-based observations of a mm-wave spectral line at 278 GHz have yielded stratospheric chlorine monoxide column density diurnal variation records which indicate that the mixing ratio and column density of this compound above 30 km are about 20 percent lower than model predictions based on 2.1 parts/billion of total stratospheric chlorine. The observed day-to-night variation is, however, in good agreement with recent model predictions, both confirming the existence of a nighttime reservoir for chlorine and verifying the predicted general rate of its storage and retrieval.

Biodegradation of chloro- and bromobenzoic acids: effect of milieu conditions and microbial community analysis.

PubMed

Gaza, Sarah; Felgner, Annika; Otto, Johannes; Kushmaro, Ariel; Ben-Dov, Eitan; Tiehm, Andreas

2015-04-28

Monohalogenated benzoic acids often appear in industrial wastewaters where biodegradation can be hampered by complex mixtures of pollutants and prevailing extreme milieu conditions. In this study, the biodegradation of chlorinated and brominated benzoic acids was conducted at a pH range of 5.0-9.0, at elevated salt concentrations and with pollutant mixtures including fluorinated and iodinated compounds. In mixtures of the isomers, the degradation order was primarily 4-substituted followed by 3-substituted and then 2-substituted halogenated benzoic acids. If the pH and salt concentration were altered simultaneously, long adaptation periods were required. Community analyses were conducted in liquid batch cultures and after immobilization on sand columns. The Alphaproteobacteria represented an important fraction in all of the enrichment cultures. On the genus level, Afipia sp. was detected most frequently. In particular, Bacteroidetes were detected in high numbers with chlorinated benzoic acids. Copyright © 2015 Elsevier B.V. All rights reserved.

Evidence that a formyl-substituted iron porphyrin is the prosthetic group of myeloperoxidase: magnetic circular dichroism similarity of the peroxidase to Spirographis heme-reconstituted myoglobin.

PubMed Central

Sono, M; Bracete, A M; Huff, A M; Ikeda-Saito, M; Dawson, J H

1991-01-01

To probe the identity of the active site heme-type prosthetic group of myeloperoxidase, whose structure has not been established unambiguously [proposed structures are (i) a chlorin (dihydroporphyrin) or (ii) a formyl-substituted porphyrin such as present in heme a], Spirographis heme (2-formyl-4-vinyldeuteroheme IX) has been incorporated into apo-myoglobin as a possible iron porphyrin model. Comparison of parallel derivatives of these two green proteins with magnetic circular dichroism spectroscopy reveals considerable similarities between several derivatives of these proteins, including the pyridine hemochromogen, the native ferric, ferrous-oxy, and ferrous-CO forms. In contrast, the magnetic circular dichroism spectra of available iron chlorin (octaethylchlorin) model complexes in analogous ligation and oxidation states do not show any significant spectral similarities to myeloperoxidase. This finding provides important evidence in favor of a formyl-substituted porphyrin as the structure of the prosthetic group macrocycle of myeloperoxidase. PMID:1662385

Chlorinated Dioxins and Furans from Kelp and Copper Sulfate ...

EPA Pesticide Factsheets

In 2002, dioxins were discovered in animal feed ingredients during a random sampling by Irish officials and subsequently traced to particular mineral supplements produced at a Minnesota plant in the United States. These products sold under the names of SQM Mineral Products and Carbosan Mineral Products provide trace minerals complexed to polysaccharides for delivery of trace minerals. The products were voluntarily recalled by the company until the source of the dioxins could be identified and the dioxins eliminated from the supplements. Preliminary investigations by the company and federal agencies indicated that the dioxins were apparently produced during the manufacturing process of supplements containing copper, zinc, manganese, magnesium and iron. Additional studies were initiated to identify the specific ingredients required for dioxin formation and to provide further insight into the conditions necessary for their production. Citation: Ferrario, J.; Byrne, C.; Winters, D.; Boone, T.; Vigo, C.; Dupuy, A.; 2003. Chlorinated Dioxins and Furans from Kelp and Copper Sulfate: Initial Investigations of Dioxin Formation in Mineral Feed Supplements. Organohalogen Compounds 63, 183-186.

Arenium ions are not obligatory intermediates in electrophilic aromatic substitution

PubMed Central

Galabov, Boris; Koleva, Gergana; Simova, Svetlana; Hadjieva, Boriana; Schaefer, Henry F.; Schleyer, Paul von Ragué

2014-01-01

Our computational and experimental investigation of the reaction of anisole with Cl2 in nonpolar CCl4 solution challenges two fundamental tenets of the traditional SEAr (arenium ion) mechanism of aromatic electrophilic substitution. Instead of this direct substitution process, the alternative addition–elimination (AE) pathway is favored energetically. This AE mechanism rationalizes the preferred ortho and para substitution orientation of anisole easily. Moreover, neither the SEAr nor the AE mechanisms involve the formation of a σ-complex (Wheland-type) intermediate in the rate-controlling stage. Contrary to the conventional interpretations, the substitution (SEAr) mechanism proceeds concertedly via a single transition state. Experimental NMR investigations of the anisole chlorination reaction course at various temperatures reveal the formation of tetrachloro addition by-products and thus support the computed addition–elimination mechanism of anisole chlorination in nonpolar media. The important autocatalytic effect of the HCl reaction product was confirmed by spectroscopic (UV-visible) investigations and by HCl-augmented computational modeling. PMID:24972792

The Connection between Model Performance on the CCMVal Transport Diagnostics and Simulated Sensitivity of Ozone to Chlorine Change

NASA Technical Reports Server (NTRS)

Douglass, Anne; Stolarski, Richard; Oman, Luke; Strahan, Susan

2012-01-01

The chemistry climate models that contributed simulations for past and future ozone evolution to the 2010 Scientific Assessment of Ozone Depletion were subject to extensive evaluation by the SPARC (Stratospheric Processes and their Role in Climate) CCMVal (Chemistry-Climate Model Validation) activity. The sensitivity of ozone to changes in composition and climate varies among the models, but the relationship between these variations and the model evaluations of CCMVal is not obvious. We have learned that the transport evaluation can be used to interpret the comparisons between observed and simulated columns of chlorine reservoirs, hydrochloric acid (HCl) and chlorine nitrate (ClONO2); these comparisons were part of the CCMVal evaluation of chemistry. The simulations with best performance on the transport diagnostics most faithfully reproduce the evolution and seasonal variation of the chlorine reservoirs as observed at NDACC (Network for Detection of Atmospheric Composition Change) stations (NyAlesund 78.9N, Kiruna 67.8N, Harestua 60.2N, Jungfraujoch 46.6N, Toronto 43.6N, Kitt Peak 31.9N, Izana 28.3N, Mauna Loa 19.5N, Lauder 45S and Arrival Heights 77.8S). In the simulations, the HCl in the lower stratosphere depends on total inorganic chlorine (Cly) and partitioning between HCl and ClON02. Total inorganic chlorine depends on the fractional release of chlorine from source gases, and ratio of ClON02 to HCl is inversely dependent on methane and varies quadratically with ozone. Simulated HCl from various models may agree with observations even though Cly is in error, partitioning is in error, or both. Simulated ozone sensitivity to chlorine is shown to be greater for models that produce larger values of chlorine nitrate for background chlorine levels, and vice versa. Comparisons with the NDACC data show why the models with 'best' transport have similar sensitivity to chlorine change. The realistic evolution of the simulated HCl and ClONO2 columns suggests realistic levels of Cly in the lower atmosphere. In addition, the wide range values for the sensitivity of ozone to chlorine obtained from the CCMVal simulations is explained by the wide range in lower atmospheric columns of ClONO2 and the concomitant wide range of levels for chlorine monoxide.

Theoretical study of the S…Cl interaction between sulfides and atomic chlorine. Nature and strength of the two-center three-electron bond

NASA Astrophysics Data System (ADS)

Sutradhar, Dipankar; Zeegers-Huyskens, Thérèse; Chandra, Asit. K.

2017-05-01

The interaction between sulfides (H2S, CH3SH, CH3CH2SH, CH3SCH3 and CH3SCH2F) and atomic chlorine is investigated using DFT based LC-BLYP and CCSD(T) methods in conjugation with the aug-cc-pVTZ basis set. The intermolecular S…Cl distances in the complexes range between 2.5922 Å (H2S…Cl) and 2.5273 Å (CH3SCH3…Cl). The interaction energies ranging between -29.1 and -77.5 kJ mol-1 reveal the formation of relatively strong 2c-3e S…Cl bonds. The binding energies are linearly related to the proton affinity of the sulfides, to the charge transfer taking place from the sulfides to the Cl atom and inversely proportional to the difference between the ionization potential of the sulfides and the electron affinity of the Cl atom. The spin density analysis suggests that almost 48% of the spin is transferred from the Cl to the S atom in the strongest CH3SCH3…Cl complex. The AIM analysis shows that the S…Cl interaction possess a significant covalent character which decreases with decreasing binding strength of the complexes. All the data indicate that the S…Cl 2c-3e bonds are stronger than the O…Cl or N…Cl bonds and more covalent in nature. The variation of the CH distances and the blue shifts of the ν(CH) vibration resulting from the interaction with Cl are discussed.

CHEMICAL ANALYSIS OF REVERSE OSMOSIS MEMBRANE AND XAD RESIN ADSORPTION CONCENTRATES OF WATER DISINFECTED BY CHLORINATION OR OZONATION/CHLORINATION PROCESSES

EPA Science Inventory

Chemical Analysis of Reverse Osmosis Membrane and XAD Resin Adsorption Concentrates of Water Disinfected by Chlorination or Ozonation/Chlorination Processes.

J. E. Simmons1, S.D. Richardson2, K.M. Schenck3, T. F. Speth3, R. J. Miltner3 and A. D. Thruston2

1 NHEE...

Imidazole catalyzes chlorination by unreactive primary chloramines

PubMed Central

Roemeling, Margo D.; Williams, Jared; Beckman, Joseph S.; Hurst, James K.

2015-01-01

Hypochlorous acid and simple chloramines (RNHCl) are stable biologically-derived chlorinating agents. In general, the chlorination potential of HOCl is much greater than that of RNHCl, allowing it to oxidize or chlorinate a much wider variety of reaction partners. However, in this study we demonstrate by kinetic analysis that the reactivity of RNHCl can be dramatically promoted by imidazole and histidyl model compounds via intermediary formation of the corresponding imidazole chloramines. Two biologically relevant reactions were investigated—loss of imidazole-catalyzed chlorinating capacity and phenolic ring chlorination using fluorescein and the tyrosine analog, 4-hydroxyphenylacetic acid (HPA). HOCl reacted stoichiometrically with imidazole, N-acetylhistidine (NAH), or imidazoleacetic acid to generate the corresponding imidazole chloramines which subsequently decomposed. Chloramine (NH2Cl) also underwent a markedly accelerated loss in chlorinating capacity when NAH was present, although in this case NAHCl did not accumulate, indicating that the catalytic intermediate must be highly reactive. Mixing HOCl with 1-methylimidazole (MeIm) led to very rapid loss in chlorinating capacity via formation of a highly reactive chlorinium ion (MeImCl+) intermediate; this behavior suggests that the reactive forms of the analogous imidazole chloramines are their conjugate acids, e.g., the imidazolechlorinium ion (HImCl+). HOCl-generated imidazole chloramine (ImCl) reacted rapidly with fluorescein in a specific acid-catalyzed second order reaction to give 3′-monochloro and 3′,5′-dichloro products. Equilibrium constants for the transchlorination reactions: HOCl + HIm = H2O + ImCl and NH2Cl + HIm = NH3 + ImCl were estimated from the dependence of the rate constants upon [HIm]/[HOCl] and literature data. Acid catalysis again suggests that the actual chlorinating agent is HImCl+; consistent with this interpretation, MeIm markedly catalyzed fluorescein chlorination by HOCl. Time-dependent imidazole-catalyzed HPA chlorination by NH2Cl was also demonstrated by product analyses. Quantitative assessment of the data suggests that physiological levels of histidyl groups will react with primary chloramines to generate a flux of imidazole chloramine sufficient to catalyze biological chlorination via HImCl+, particularly in environments that generate high concentrations of HOCl such as the neutrophil phagosome. PMID:25660996

Chlorine Stable Isotopes to reveal contribution of magmatic chlorine in subduction zones: the case of the Kamchatka-Kuril and the Lesser Antilles Volcanic Arcs

NASA Astrophysics Data System (ADS)

Agrinier, Pierre; Shilobreeva, Svetlana; Bardoux, Gerard; Michel, Agnes; Maximov, Alexandr; Kalatcheva, Elena; Ryabinin, Gennady; Bonifacie, Magali

2015-04-01

By using the stable isotopes of chlorine (δ 37Cl), we have shown that magmatic chlorine (δ 37Cl ≤ -0.6 ‰ [1]) is different from surface chlorine (δ 37Cl ≈ 0 ‰ [1]) in hydrothermal system of Soufrière and Montagne Pelé from the young arc volcanic system of Lesser Antilles. First measurements on condensed chlorides from volcanic gases (e.g. [2], [3]) did not permitted to get sensible δ 37Cl values on degassed chlorine likely because chlorine isotopes are fractionated during the HClgas - chloride equilibrium in the fumaroles or during sampling artifacts. Therefore we have developed an alternative strategy based on the analysis of chloride in thermal springs, streams, sout{f}lowing on the flanks of the volcanoes. Due to the highly hydrophilic behavior of Cl, we hypothesize that thermal springs incorporate chlorine without fractionation of chlorine isotopes and might reflect the chlorine isotopic composition degassed by magmas [1]. Indeed Thermal spring with low δ 37Cl chlorides (≤ -0.6 perthousand{}) are linked with magmatic volatiles characters (3He ratio at 5 Ra at and δ 13C CO2 quad ≈ -3 perthousand{}). To go further in the potentiality of using the Chlorine isotopes to reveal contribution of magmatic chlorine in volcanic systems, we have started the survey of thermal springs and wells waters in the Kamchatka-Kuril volcanic mature Arc (on sites Mutnovsky, Paratunka, Nalychevsky, Khodutkinsky, Paramushir Island, identified by Taran, 2009 [4] for concentrations of chloride). Preliminary results show δ 37Cl values ranging from 0.5 to -0.2 ‰ and generally higher chloride concentrations. The δ 37Cl values are higher than the value recorded for the young arc volcanic system of lesser Antilles. At present moment very few negative δ 37Cl have been measured in the Kamchatka-Kuril volcanic mature Arc. [1] Li et al., 2015 EPSL in press. [2] Sharp et al. 2010 GCA. [3] Rizzo et al., 2013, EPSL, 371, 134. [4] Taran, 2009, GCA, 73, 1067

Decontamination of Pangasius fish (Pangasius hypophthalmus) with chlorine or peracetic acid in the laboratory and in a Vietnamese processing company.

PubMed

Tong Thi, Anh Ngoc; Sampers, Imca; Van Haute, Sam; Samapundo, Simbarashe; Ly Nguyen, Binh; Heyndrickx, Marc; Devlieghere, Frank

2015-09-02

This study evaluated the decontamination of Pangasius fillets in chlorine or peracetic acid treated wash water. First, the decontamination efficacy of the washing step with chlorinated water applied by a Vietnamese processing company during trimming of Pangasius fillets was evaluated and used as the basis for the experiments performed on a laboratory scale. As chlorine was only added at the beginning of the batch and used continuously without renewal for 239min; a rapid increase of the bacterial counts and a fast decrease of chlorine in the wash water were found. This could be explained by the rapid accumulation of organic matter (ca. 400mg O2/L of COD after only 24min). Secondly, for the experiments performed on a laboratory scale, a single batch approach (one batch of wash water for treating a fillet) was used. Chlorine and PAA were evaluated at 10, 20, 50 and 150ppm at contact times of 10, 20 and 240s. Washing with chlorine and PAA wash water resulted in a reduction of Escherichia coli on Pangasius fish which ranged from 0-1.0 and 0.4-1.4logCFU/g, respectively while less to no reduction of total psychrotrophic counts, lactic acid bacteria and coliforms on Pangasius fish was observed. However, in comparison to PAA, chlorine was lost rapidly. As an example, 53-83% of chlorine and 15-17% of PAA were lost after washing for 40s (COD=238.2±66.3mg O2/L). Peracetic acid can therefore be an alternative sanitizer. However, its higher cost will have to be taken into consideration. Where (cheaper) chlorine is used, the processors have to pay close attention to the residual chlorine level, pH and COD level during treatment for optimal efficacy. Copyright © 2015. Published by Elsevier B.V.

Effects of Chlorine on Enterovirus RNA Degradation

EPA Science Inventory

The primary mechanism of disinfection of waterborne pathogens by chlorine has always been believed to be due to the alteration of proteins by free chlorine and subsequent disruption of their biological structure.

The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

NASA Astrophysics Data System (ADS)

Müller, Rolf; Grooß, Jens-Uwe; Mannan Zafar, Abdul; Robrecht, Sabine; Lehmann, Ralph

2018-03-01

The Antarctic ozone hole arises from ozone destruction driven by elevated levels of ozone destroying (active) chlorine in Antarctic spring. These elevated levels of active chlorine have to be formed first and then maintained throughout the period of ozone destruction. It is a matter of debate how this maintenance of active chlorine is brought about in Antarctic spring, when the rate of formation of HCl (considered to be the main chlorine deactivation mechanism in Antarctica) is extremely high. Here we show that in the heart of the ozone hole (16-18 km or 85-55 hPa, in the core of the vortex), high levels of active chlorine are maintained by effective chemical cycles (referred to as HCl null cycles hereafter). In these cycles, the formation of HCl is balanced by immediate reactivation, i.e. by immediate reformation of active chlorine. Under these conditions, polar stratospheric clouds sequester HNO3 and thereby cause NO2 concentrations to be low. These HCl null cycles allow active chlorine levels to be maintained in the Antarctic lower stratosphere and thus rapid ozone destruction to occur. For the observed almost complete activation of stratospheric chlorine in the lower stratosphere, the heterogeneous reaction HCl + HOCl is essential; the production of HOCl occurs via HO2 + ClO, with the HO2 resulting from CH2O photolysis. These results are important for assessing the impact of changes of the future stratospheric composition on the recovery of the ozone hole. Our simulations indicate that, in the lower stratosphere, future increased methane concentrations will not lead to enhanced chlorine deactivation (through the reaction CH4 + Cl → HCl + CH3) and that extreme ozone destruction to levels below ≈ 0.1 ppm will occur until mid-century.

Stimulation of 2-methylisoborneol (MIB) production by actinomycetes after cyclic chlorination in drinking water distribution systems.

PubMed

Abbaszadegan, Morteza; Yi, Min; Alum, Absar

2015-01-01

The impact of fluctuation in chlorine residual on actinomycetes and the production of 2-methylisoborneol (MIB) were studied in cast-iron and PVC model distribution systems. Actinomycetes were spiked in each system and continued operation for a 12-day non-chlorine experiment, resulting in no changes in actinomycetes and MIB concentrations. Three cyclic chlorination events were performed and chlorine residuals were maintained as follows: 1.0 mg L(-1) for 24 h, 0 mg L(-1) for 48 h, 0.5 mg L(-1) for 48 h, 0 mg L(-1) for 48 h and 2 mg L(-1) for 24 h. After each chlorination event, 2 -3 log decrease in actinomycetes was noted in both systems. However, within 48 h at 0 mg L(-1) chlorine, the actinomycetes recovered to the pre-chlorination levels. On the contrary, MIB concentration in both systems remained un-impacted after the first cycle and increased by fourfold (< 5 to > 20 mg L(-1)) after the second cycle, which lasted through the third cycle despite the fact that actinomycetes numbers fluctuated 2-3 logs during this time period. For obtaining biofilm samples from field, water meters were collected from municipality drinking water distribution systems located in central Arizona. The actinomycetes concentration in asbestos cement pipe and cast iron pipe averaged 3.1 × 10(3) and 1.9 × 10(4) CFU cm(-2), respectively. The study shows that production of MIB is associated with changes in chlorine residual in the systems. This is the first report of cyclic chlorine shock as a stimulus for MIB production by actinomycetes in drinking water distribution system's ecology.

Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

PubMed

Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

2016-09-15

Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oxygen Administration Improves Survival but Worsens Cardiopulmonary Functions in Chlorine-exposed Rats.

PubMed

Okponyia, Obiefuna C; McGraw, Matthew D; Dysart, Marilyn M; Garlick, Rhonda B; Rioux, Jacqueline S; Murphy, Angela L; Roe, Gates B; White, Carl W; Veress, Livia A

2018-01-01

Chlorine is a highly reactive gas that can cause significant injury when inhaled. Unfortunately, its use as a chemical weapon has increased in recent years. Massive chlorine inhalation can cause death within 4 hours of exposure. Survivors usually require hospitalization after massive exposure. No countermeasures are available for massive chlorine exposure and supportive-care measures lack controlled trials. In this work, adult rats were exposed to chlorine gas (LD 58-67 ) in a whole-body exposure chamber, and given oxygen (0.8 Fi O 2 ) or air (0.21 Fi O 2 ) for 6 hours after baseline measurements were obtained. Oxygen saturation, vital signs, respiratory distress and neuromuscular scores, arterial blood gases, and hemodynamic measurements were obtained hourly. Massive chlorine inhalation caused severe acute respiratory failure, hypoxemia, decreased cardiac output, neuromuscular abnormalities (ataxia and hypotonia), and seizures resulting in early death. Oxygen improved survival to 6 hours (87% versus 42%) and prevented observed seizure-related deaths. However, oxygen administration worsened the severity of acute respiratory failure in chlorine-exposed rats compared with controls, with increased respiratory acidosis (pH 6.91 ± 0.04 versus 7.06 ± 0.01 at 2 h) and increased hypercapnia (180.0 ± 19.8 versus 103.2 ± 3.9 mm Hg at 2 h). In addition, oxygen did not improve neuromuscular abnormalities, cardiac output, or respiratory distress associated with chlorine exposure. Massive chlorine inhalation causes severe acute respiratory failure and multiorgan damage. Oxygen administration can improve short-term survival but appears to worsen respiratory failure, with no improvement in cardiac output or neuromuscular dysfunction. Oxygen should be used with caution after massive chlorine inhalation, and the need for early assisted ventilation should be assessed in victims.

The fate of chlorinated aliphatics in anaerobic treatment under transient loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Y.C.

1993-01-01

A CSTR with dispersed-growth anaerobic bacteria that simultaneously remove COD and chlorinated aliphatics was used. Seven chlorinated aliphatics (methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, 1,1-dichloroethylene, trichloroethylene, and tetrachloroethylene) were biotransformed into lower-chlorinated compounds by anaerobic treatment, utilizing propionic acid (HPr) or acetic acid (HAc). The microorganisms supplied with HAc grew and were sustained at higher BSS concentrations (4,500 to 11,000 mg/L) than those with HPr (2,000 to 5,000 mg/L). The anaerobic treatment process has a considerable potential for acclimation to and biotransformation of toxic chlorinated aliphatics. For providing a safe operation range, the maximum loading rates of the chlorinated aliphaticsmore » are defined as the observed daily injection of those compounds which resulted in 50% activity of the biomass. Based on the reactor volume, the maximum chlorinated compound loading rates to the microorganisms metabolizing HPr were from 0.4 to 90 mg/L-day, while the rates ranged from 0.6 to 190 mg/L-day for the microorganisms metabolizing HAc. When based on biomass, the maximum loading rates of the microorganisms metabolizing HPr were from 0.2 to 26 mg/g cell-day, while rates for the microorganisms metabolizing HAc ranged from 0.1 to 19 mg/g cell-day. Anaerobic microorganisms have higher resistance to chlorinated aliphatic alkenes than alkanes, and can biotransform about 0.04 to 68 pound chlorinated aliphatics while simultaneously metabolizing 1,000 pounds COD. Therefore, within the safe operation range, the anaerobic process can stabilize organic pollution at a high rate while still biotransforming chlorinated aliphatics.« less

Influence of long-range atmospheric transportation (LRAT) on mono-to octa-chlorinated PCDD/Fs levels and distributions in soil around Qinghai Lake, China.

PubMed

Han, Ying; Liu, Wenbin; Hansen, Hans Chr Bruun; Chen, Xuebin; Liao, Xiao; Li, Haifeng; Wang, Mengjing; Yan, Nan

2016-08-01

Long-range atmospheric transportation (LRAT) of persistent organic pollutants followed by their deposition in cold, arid regions is of wide concern. This problem occurs at Qinghai Lake in the northeastern Tibetan Plateau, a sparsely populated area with extreme weather conditions and little current or historical anthropogenic pollution. The concentrations and distribution patterns of the mono-to octa-chlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) congeners in surface soil samples collected from around Qinghai Lake were quantified. Concentration differences between low-(mono-to tri-) chlorinated PCDD/Fs and high-(tetra-to octa-) chlorinated PCDD/Fs were measured. High PCDD/F levels were detected, with total concentrations of 15,108 ± 6323 pg/g for the 27 PCDD/F congeners and 15,104 ± 6324 pg/g for the low-chlorinated PCDD/Fs. The concentrations of 17 2,3,7,8-substituted PCDD/Fs were only 3.1 ± 4.4 pg/g and the corresponding international toxicity equivalency (I-TEQ) was 0.11 ± 0.22 pg I-TEQ/g. Given their higher vapor pressures and lower boiling points, low-chlorinated PCDD/Fs, were predominantly gaseous, whereas high-chlorinated PCDD/Fs were predominantly solid, indicating that there is a higher potential for long-range transport of low-chlorinated PCDD/Fs. Overall, because of their high LRAT potential, low-chlorinated PCDD/Fs may pose a greater risk to local ecosystems in cold, remote areas than high-chlorinated PCDD/Fs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toxicity of chlorine to zebrafish embryos

PubMed Central

Kent, Michael L.; Buchner, Cari; Barton, Carrie; Tanguay, Robert L.

2014-01-01

Surface disinfection of fertilized fish eggs is widely used in aquaculture to reduce extraovum pathogens that may be released from brood fish during spawning, and this is routinely used in zebrafish (Danio rerio) research laboratories. Most laboratories use approximately 25 – 50 ppm unbuffered chlorine solution for 5 – 10 min. Treatment of embryos with chlorine has significant germicidal effects for many Gram-negative bacteria, viruses, and trophozoite stages of protozoa, it has reduced efficacy against cyst or spore stages of protozoa and certain Mycobacterium spp. Therefore, we evaluated the toxicity of unbufferred and buffered chlorine solution to embryos exposed at 6 or 24 hours post-fertilization (hpf) to determine if higher concentrations can be used for treating zebrafish embryos. Most of our experiments entailed using an outbred line (5D), with both mortality and malformations as endpoints. We found that 6 hpf embryos consistently were more resistant than 24 hpf embryos to the toxic effects of chlorine. Chlorine is more toxic and germicidal at lower pHs, and chlorine causes elevated pH. Consistent with this, we found that unbufferred chlorine solutions (pH ca 8–9) were less toxic at corresponding concentrations than solutions buffered to pH 7. Based on our findings here, we recommend treating 6 hpf embryos for 10 min and 24 hpf for 5 min with unbuffered chlorine solution at 100 ppm. One trial indicated that AB fish, a popular outbred line, are more susceptible to toxicity than 5Ds. This suggests that variability between zebrafish lines occurs, and researchers should evaluate each line or strain under their particular laboratory conditions for selection of the optimum chlorine treatment procedure. PMID:24429474

Effectiveness of emergency water treatment practices in refugee camps in South Sudan

PubMed Central

Ali, Syed Saad; Fesselet, Jean-Francois

2015-01-01

Abstract Objective To investigate the concentration of residual chlorine in drinking water supplies in refugee camps, South Sudan, March–April 2013. Methods For each of three refugee camps, we measured physical and chemical characteristics of water supplies at four points after distribution: (i) directly from tapstands; (ii) after collection; (iii) after transport to households; and (iv) after several hours of household storage. The following parameters were measured: free and total residual chlorine, temperature, turbidity, pH, electrical conductivity and oxidation reduction potential. We documented water handling practices with spot checks and respondent self-reports. We analysed factors affecting residual chlorine concentrations using mathematical and linear regression models. Findings For initial free residual chlorine concentrations in the 0.5–1.5 mg/L range, a decay rate of ~5x10-3 L/mg/min was found across all camps. Regression models showed that the decay of residual chlorine was related to initial chlorine levels, electrical conductivity and air temperature. Covering water storage containers, but not other water handling practices, improved the residual chlorine levels. Conclusion The concentrations of residual chlorine that we measured in water supplies in refugee camps in South Sudan were too low. We tentatively recommend that the free residual chlorine guideline be increased to 1.0 mg/L in all situations, irrespective of diarrhoeal disease outbreaks and the pH or turbidity of water supplies. According to our findings, this would ensure a free residual chlorine level of 0.2 mg/L for at least 10 hours after distribution. However, it is unknown whether our findings are generalizable to other camps and further studies are therefore required. PMID:26478612

21 CFR 137.200 - Whole wheat flour.

Code of Federal Regulations, 2011 CFR

2011-04-01

... not more than 45 parts per million) or chlorine dioxide, or chlorine, or a mixture of nitrosyl chloride and chlorine, may be added in a quantity not more than sufficient for bleaching and artificial...

Reductive dechlorination of trichloroethene mediated by humic-metal complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

O`Loughlin, E.J.; Burris, D.R.; Delcomyn, C.A.

1999-04-01

Experiments were conducted to determine if transition metal-humic acid complexes can act as e{sup {minus}} transfer mediators in the reductive dechlorination of trichloroethene (TCE) using Ti(III) citrate as the bulk reductant. In the presence of Ni-Aldrich humic acid (AHA) complexes, TCE reduction was rapid, with complete removal of TCE in less than 23 h. Cu-AHA complexes were less effective as e{sup {minus}} mediators than Ni-AHA complexes; only 60% of TCE was reduced after 150 h. Partially dechlorinated intermediates were observed during TCE reduction; however, they were transitory, and at no time accounted for more than 2% of the initial TCEmore » mass on a mole C basis. Ethane and ethene were the primary end products of TCE reduction; however, a suite of other non-chlorinated hydrocarbons consisting of methane and C{sub 3} to C{sub 6} alkanes and alkenes were also observed. The results suggest that humic-metal complexes may represent a previously unrecognized class of electron mediators in natural environments.« less

Automatic electrochemical ambient air monitor for chloride and chlorine

DOEpatents

Mueller, Theodore R.

1976-07-13

An electrochemical monitoring system has been provided for determining chloride and chlorine in air at levels of from about 10-1000 parts per billion. The chloride is determined by oxidation to chlorine followed by reduction to chloride in a closed system. Chlorine is determined by direct reduction at a platinum electrode in 6 M H.sub.2 SO.sub.4 electrolyte. A fully automated system is utilized to (1) acquire and store a value corresponding to electrolyte-containing impurities, (2) subtract this value from that obtained in the presence of air, (3) generate coulometrically a standard sample of chlorine mixed with air sample, and determine it as chlorine and/or chloride, and (4) calculate, display, and store for permanent record the ratio of the signal obtained from the air sample and that obtained with the standard.

Life Cycle Environmental Impacts of Disinfection Technologies Used in Small Drinking Water Systems.

PubMed

Jones, Christopher H; Shilling, Elizabeth G; Linden, Karl G; Cook, Sherri M

2018-03-06

Small drinking water systems serve a fifth of the U.S. population and rely heavily on disinfection. While chlorine disinfection is common, there is interest in minimizing chemical addition, especially due to carcinogenic disinfection byproducts and chlorine-resistant pathogens, by using ultraviolet technologies; however, the relative, broader environmental impacts of these technologies are not well established, especially in the context of small (<10 000 people) water systems. The objective of this study was to identify environmental trade-offs between chlorine and ultraviolet disinfection via comparative life cycle assessment. The functional unit was the production of 1 m 3 of drinking water to U.S. Treatment included cartridge filtration followed by either chlorine disinfection or ultraviolet disinfection with chlorine residual addition. Environmental performance was evaluated for various chlorine contact zone materials (plastic, concrete, steel), ultraviolet validation factors (1.2 to 4.4), and electricity sources (renewable; U.S. average, high, and low impact grids). Performance was also evaluated when filtration and chlorine residual were not required. From a life cycle assessment perspective, replacing chlorine with UV was preferred only in a limited number of cases (i.e., high pumping pressure but filtration is not required). In all others, chlorine was environmentally preferred, although some contact zone materials and energy sources had an impact on the comparison. Utilities can use these data to inform their disinfection technology selection and operation to minimize environmental and human health impacts.

Application of an electrochemical chlorine-generation system combined with solar energy as appropriate technology for water disinfection.

PubMed

Choi, Jusol; Park, Chan Gyu; Yoon, Jeyong

2013-02-01

Affordable water disinfection is key to reducing the waterborne disease experienced worldwide where resources are limited. A simple electrochemical system that can generate chlorine as a disinfectant from the electrolysis of sodium chloride is an appropriate technology to produce clean water, particularly if driven by solar energy. This study examined the affordability of an electrochemical chlorine generation system using solar energy and developed the necessary design information for its implementation. A two-electrode batch reactor, equipped with commercial IrO(2)-coated electrodes and a solar panel (approximate area 0.2 m(2)), was used to produce chlorine from a 35g/L solution of NaCl. Within 1 h, sufficient chlorine (0.8 g) was generated to produce clean drinking water for about 80 people for 1 day (target microorganism: Escherichia coli; daily drinking water requirement: 2 L per person; chlorine demand: 4 mg/L; solar power: 650 W/m(2) in Seoul, Korea. Small household batteries were demonstrated to be a suitable alternative power source when there is insufficient solar irradiation. Using a 1 m(2) solar panel, the reactor would take only 15 min in Seoul, Korea, or 7 min in the tropics (solar power 1300 W/m(2)), to generate 1 g of chlorine. The solar-powered electrochemical chlorine generation system for which design information is provided here is a simple and affordable way to produce chlorine with which to convert contaminated water into clean drinking water.

Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mo, Daize; Wang, Huan; Chen, Hui

Here, halogenation is an effective way to tune the energy levels of organic semiconducting materials. To date, fluorination of organic semiconducting materials to fabricate polymer solar cells (PSCs) has been used far more than chlorination; however, fluorine exchange reactions suffer from low yields and the resulting fluorinated polymer always comes with higher price, which will greatly hinder their commercial applications. Herein, we designed and synthesized a series of chlorinated donor-acceptor (D-A) type polymers, in which benzo[1,2-b:4,5- b]dithiophene and chlorinated benzothiadiazole units are connected by thiophene π-bridges with an asymmetric alkyl chain. These chlorinated polymers showed deep highest occupied molecular orbitalmore » energy levels, which promoted the efficiency of their corresponding PSCs by increasing the device open circuit voltage. The asymmetric alkyl chain on the thiophene moieties gave the final polymer sufficient solubility for solution processing and strong π-π stacking in films allowed for high mobility. Although the introduction of a large chlorine atom increased the torsion angle of the polymer backbone, the chlorinated polymers maintained high crystallinity and a favorable backbone orientation in the blended films. These factors contributed to respectable device performances from thick-film devices, which showed PCEs as high as 9.11% for a 250 nm-thick active layer. These results demonstrate that chlorination is a promising method to fine tune the energy levels of conjugated polymers, and chlorinated benzothiadiazole may be a versatile building block in materials for efficient solar energy conversion.« less

Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells

DOE PAGES

Mo, Daize; Wang, Huan; Chen, Hui; ...

2017-03-08

Here, halogenation is an effective way to tune the energy levels of organic semiconducting materials. To date, fluorination of organic semiconducting materials to fabricate polymer solar cells (PSCs) has been used far more than chlorination; however, fluorine exchange reactions suffer from low yields and the resulting fluorinated polymer always comes with higher price, which will greatly hinder their commercial applications. Herein, we designed and synthesized a series of chlorinated donor-acceptor (D-A) type polymers, in which benzo[1,2-b:4,5- b]dithiophene and chlorinated benzothiadiazole units are connected by thiophene π-bridges with an asymmetric alkyl chain. These chlorinated polymers showed deep highest occupied molecular orbitalmore » energy levels, which promoted the efficiency of their corresponding PSCs by increasing the device open circuit voltage. The asymmetric alkyl chain on the thiophene moieties gave the final polymer sufficient solubility for solution processing and strong π-π stacking in films allowed for high mobility. Although the introduction of a large chlorine atom increased the torsion angle of the polymer backbone, the chlorinated polymers maintained high crystallinity and a favorable backbone orientation in the blended films. These factors contributed to respectable device performances from thick-film devices, which showed PCEs as high as 9.11% for a 250 nm-thick active layer. These results demonstrate that chlorination is a promising method to fine tune the energy levels of conjugated polymers, and chlorinated benzothiadiazole may be a versatile building block in materials for efficient solar energy conversion.« less

Sequential UV- and chlorine-based disinfection to mitigate Escherichia coli in drinking water biofilms.

PubMed

Murphy, H M; Payne, S J; Gagnon, G A

2008-04-01

This study was designed to examine the potential downstream benefits of sequential disinfection to control the persistence of Escherichia coli under conditions relevant to drinking water distribution systems. Eight annular reactors (four polycarbonate and four cast iron) were setup in parallel to address various factors that could influence biofilm growth in distribution systems. Eight reactors were treated with chlorine, chlorine dioxide and monochloramine alone or in combination with UV to examine the effects on Escherichia coli growth and persistence in both the effluent and biofilm. In general, UV-treated systems in combination with chlorine or chlorine dioxide and monochloramine achieved greater log reductions in both effluent and biofilm than systems treated with chlorine-based disinfectants alone. However, during UV-low chlorine disinfection, E. coli was found to persist at low levels, suggesting that the UV treatment had instigated an adaptive mutation. During UV-chlorine-dioxide treatment, the E. coli that was initially below the detection limit reappeared during a low level of disinfection (0.2 mg/L) in the cast iron systems. Chloramine was shown to be effective in disinfecting suspended E. coli in the effluent but was unable to reduce biofilm counts to below the detection limit. Issues such as repair mechanism of E. coli and nitrification could help explain some of these aberrations. Improved understanding of the ability of chlorine-based disinfectant in combination with UV to provide sufficient disinfection will ultimately effect in improved management and safety of drinking water.

Bank security dye packs: synthesis, isolation, and characterization of chlorinated products of bleached 1-(methylamino)anthraquinone.

PubMed

Egan, James M; Rickenbach, Michael; Mooney, Kim E; Palenik, Chris S; Golombeck, Rebecca; Mueller, Karl T

2006-11-01

Banknote evidence is often submitted after a suspect has attempted to disguise or remove red dye stain that has been released because of an anti-theft device that activates after banknotes have been unlawfully removed from bank premises. Three chlorinated compounds have been synthesized as forensic chemical standards to indicate bank security dye bleaching as a suspect's intentional method for masking a robbery involving dye pack release on banknotes. A novel, facile synthetic method to provide three chlorinated derivatives of 1-(methylamino)anthraquinone (MAAQ) is presented. The synthetic route involved Ultra Clorox bleach as the chlorine source, iron chloride as the catalyst, and MAAQ as the starting material and resulted in a three-component product mixture. Two mono-chlorinated isomers (2-chloro-1-(methylamino)anthraquinone and 4-chloro-1-(methylamino)anthraquinone) and one di-chlorinated compound (2,4-dichloro-1-(methylamino)anthraquinone) of the MAAQ parent molecule were detected by gas chromatography mass spectrometry (GC-MS), and subsequently isolated by liquid chromatography (LC) with postcolumn fraction collection. Although GC-MS is sensitive enough to detect all of the chlorinated products, it is not definitive enough to identify the structural isomers. Liquid-state nuclear magnetic resonance (NMR) spectroscopy was utilized to elucidate structurally the ortho- and para-mono-chlorinated isomers once enough material was properly isolated. A reaction mechanism involving iron is proposed to explain the presence of chlorinated MAAQ species on stolen banknotes after attempted bleaching.

Investigation of the mechanism of chlorination of glyphosate and glycine in water.

PubMed

Mehrsheikh, Akbar; Bleeke, Marian; Brosillon, Stephan; Laplanche, Alain; Roche, Pascal

2006-09-01

The chlorination reactions of glyphosate and glycine in water were thoroughly studied. Utilizing isotopically enriched (13C and 15N) samples of glycine and glyphosate and 1H, 13C, 31P, and 15N NMR spectroscopy we were able to identify all significant terminal chlorination products of glycine and glyphosate, and show that glyphosate degradation closely parallels that of glycine. We have determined that the C1 carboxylic acid carbon of glycine/glyphosate is quantitatively converted to CO2 upon chlorination. The C2 methylene carbon of glycine/glyphosate is converted to CO2 and methanediol. The relative abundance of these two products is a function of the pH of the chlorination reactions. Under near neutral to basic reaction conditions (pH 6-9), CO2 is the predominant product, whereas, under acidic reaction conditions (pH < 6) the formation of methanediol is favored. The C3 phosphonomethylene carbon of glyphosate is quantitatively converted to methanediol under all conditions tested. The nitrogen atom of glycine/glyphosate is transformed into nitrogen gas and nitrate, and the phosphorus moiety of glyphosate produces phosphoric acid upon chlorination. In addition to these terminal chlorination products, a number of labile intermediates were also identified including N-chloromethanimine, N-chloroaminomethanol, and cyanogen chloride. The chlorination products identified in this study are not unique to glyphosate and are similar to those expected from chlorination of amino acids, proteins, peptides, and many other natural organic matters present in drinking water.

Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate.

PubMed

Rodríguez, Eva; Onstad, Gretchen D; Kull, Tomas P J; Metcalf, James S; Acero, Juan L; von Gunten, Urs

2007-08-01

As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.

Development of a Portable Binary Chlorine Dioxide Generator for Decontamination

DTIC Science & Technology

2010-03-01

chlorine dioxide forms slowly from chlorite solutions through either acid release or a radical chain reaction that we observed at neutral pH. Task 7... Chlorine dioxide and water in methanol - no agent control F. 5.25% Bleach G. Methanol only 3.0 PROCEDURES 3.1 METHOD VALIDATION The reaction...error range in gas chromatography measurements. For the chlorine dioxide containing samples, mass spectra were analyzed to determine potential

Characterizing chlorine oxidation of dissolved organic matter and disinfection by-product formation with fluorescence spectroscopy and parallel factor analysis

NASA Astrophysics Data System (ADS)

Beggs, Katherine M. H.; Summers, R. Scott; McKnight, Diane M.

2009-12-01

Relationships between chlorine demand and disinfection by-product (DBP) formation during chlorination and fluorescence of dissolved organic matter (DOM) were developed. Fluorescence excitation and emission (EEM) spectroscopy was employed, and parameters including fluorescence index, redox index, and overall fluorescence intensity (OFI) were correlated to chlorine demand and DBP formation. The EEMs were also analyzed using a well established global parallel factor analysis (PARAFAC) model which resolves the fluorescence signal into 13 components, including quinone-like and protein-like components. Over an 8-day chlorination period the OFI and sum of the 13 PARAFAC loadings decreased by more than 70%. The remaining identified quinone-like compounds within the DOM were shifted to a more oxidized state. Quinone fluorescence was strongly correlated to both reduced fluorescence intensity and to chlorine demand which indicates that fluorescence may be used to track the chlorine oxidation of DOM. Quinone fluorescence was also correlated strongly with both classes of regulated DBPs: total trihalomethanes and haloacetic acids. Quinone-like components were found to be strongly correlated to overall, short-term, and long-term specific DBP formation. The results of this study show that fluorescence is a useful tool in tracking both DOM oxidation and DBP formation during chlorination.

Solar light irradiation significantly reduced cytotoxicity and disinfection byproducts in chlorinated reclaimed water.

PubMed

Lv, Xiao-Tong; Zhang, Xue; Du, Ye; Wu, Qian-Yuan; Lu, Yun; Hu, Hong-Ying

2017-11-15

Chlorinated reclaimed water is widely used for landscaping and recreational purposes, resulting in human exposure to toxic disinfection byproducts. Although the quality of chlorinated reclaimed water might be affected by sunlight during storage, the effects of solar light irradiation on the toxicity remain unknown. This study investigated the changes in cytotoxicity and total organic halogen (TOX) of chlorinated reclaimed water exposed to solar light. Irradiation with solar light for 12 h was found to significantly reduce the cytotoxicity of chlorinated reclaimed water by about 75%, with ultraviolet light being responsible for the majority of this reduction. Chlorine residual in reclaimed water tended to increase the cytotoxicity, and the synergy between solar light and free chlorine could not enhance the reduction of cytotoxicity. Adding hydroxyl radical scavengers revealed that the contribution of hydroxyl radical to cytotoxicity reduction was limited. Solar light irradiation concurrently reduced TOX. The low molecular weight (<1 kDa) fraction was the major contributor of cytotoxicity and TOX in chlorinated reclaimed water. Detoxification of the low molecular weight fraction by light irradiation was mainly a result of TOX dehalogenation, while detoxification of the high molecular weight (>1 kDa) fraction was probably caused by photoconversion from high toxic TOX to low toxic TOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorine Disinfection of Atypical Mycobacteria Isolated from a Water Distribution System

PubMed Central

Le Dantec, Corinne; Duguet, Jean-Pierre; Montiel, Antoine; Dumoutier, Nadine; Dubrou, Sylvie; Vincent, Véronique

2002-01-01

We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C · t value (product of the disinfectant concentration and contact time) of 60 mg · min · liter−1, frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C · t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4°C to 25°C) and a decrease in pH result in better inactivation. PMID:11872446

Do 'chlorine covers' exert a sustained bactericidal effect on the bacterial hand flora?

PubMed

Koller, W; Rotter, M L; Gottardi, W

1995-11-01

Treatment of skin with chlorine generates 'chlorine covers' which, in a previous study, exerted significant sustained bactericidal effects against transient skin flora on the upper arm and forearm. In this investigation, this effect was studied on both the transient and resident flora of the hands using test models for the evaluation of hand disinfectants as agreed upon in Austria and Germany. Chlorine covers were generated by bathing hands in a solution of 2% sodium tosylchloramide for 1 min. Subsequently, this cover was destroyed on one, randomly selected, hand by bathing it in a solution of 0.5% sodium thiosulphate for 15 s. The amount of chlorine on the fingertips of chlorinated hands was 2.2 +/- 0.4 micrograms/cm2; that on subsequently dechlorinated hands was 0.2 +/- 0.1 microgram/cm2. In experiments with artificially contaminated hands (Escherichia coli), the kinetics of bacterial die-off were the same on both hands. Also, in experiments with resident flora, the kinetics of bacterial die-off did not suggest bacterial reductions that increase with the duration of contact with the chlorine cover. It was concluded that with the test models used, a significant sustained antimicrobial effect of the chlorine cover could not be demonstrated on hands.

Effects of free and combined chlorine and exposure duration on rainbow trout, channel catfish, and emerald shiners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, A.S.; Bartos, J.M.

1984-11-01

Laboratory bioassays to determine the acute toxicity of monochloramine, dichloramine, hypochlorous acid, and hypochlorite ion to emerald shiners Notropis atherinoides, channel catfish Ictalurus punctatus, and rainbow trout Salmo gairdneri were conducted. Four exposure regimes typical of chlorination schedules at operating steam electric power plants were used. Fish were exposed for single 15-minute, 30-minute, 120-minute, and 4 x 30-minute periods. Based on median lethal concentrations (LC50s), the nominal solution of hypochlorous acid was the most toxic, followed closely by the solution dominated by dichloramine; nominal monochloramine and hypochlorite ion solutions had a third to a quarter the toxicity of the othermore » two. On the average, emerald shiners were 1.8 times more sensitive than channel catfish and 3.3 times more sensitive than rainbow trout to the four forms of chlorine. The fish were most tolerant of chlorine during short-duration exposures and least tolerant during the continuous 120-minute exposures. The differences in toxicity noted among the chlorine forms suggest that, when chlorination regimes and regulations are established, careful attention should be paid not only to total residual chlorine but to both the chlorine forms and fish species present and the duration of exposure. 24 references, 1 figure, 1 table.« less

Does chlorination of seawater reverse osmosis membranes control biofouling?

PubMed

Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

2015-07-01

Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Combined use of active chlorine and coagulants for drinking water purification and disinfection].

PubMed

Rakhmanin, Iu A; Zholdakova, Z I; Poliakova, E E; Kir'ianova, L F; Miasnikov, I N; Tul'skaia, E A; Artemova, T Z; Ivanova, L V; Dmitrieva, R A; Doskina, T V

2004-01-01

The authors made an experimental study of the efficiency of water purification procedures based on the combined use of active chlorine and coagulants and hygienically evaluated the procedures. The study included the evaluation of water disinfection with various coagulants and active chlorine; the investigation of the processes of production of deleterious organic chlorine compounds; the assessment of the quality of water after its treatment. The coagulants representing aluminum polyoxychloride: RAX-10 (AQUA-AURATE 10) and RAX-18 (AQUA-AURATE 18), and aluminum sulfate, technically pure grade were tested. The treatment of river water with the coagulants RAX-10 and RAX-18, followed by precipitation, filtration, and chlorination under laboratory conditions, was shown to result in water disinfection to the levels complying with the requirements described in SanPiN 2.1.4.1074-01. RAX-18 showed the best disinfecting activity against total and heat-tolerant coliform bacteria, but also to the highly chlorine-resistant microrganisms--the spores of sulfite-reducing Clostridia, phages, and viruses. Since the coagulants have an increased sorptive capacity relative to humus and other organic substances, substitution of primary chlorination for coagulant treatment may induce a reduction in the risk of formation of oncogenically and mutagenically hazardous chlorinated hydrocarbons.

Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries.

PubMed

Preston, Kelsey; Lantagne, Daniele; Kotlarz, Nadine; Jellison, Kristen

2010-03-01

Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.

Extraction of titanium from low-iron nitrided Malaysian ilmenite by chlorination

NASA Astrophysics Data System (ADS)

Ibrahim, Najwa; Ahmadi, Eltefat; Rahman, Shaik Abdul; Fauzi, M. N. Ahmad; Rezan, Sheikh Abdul

2017-01-01

In this paper, production of TiCl4 from low-iron nitrided ilmenite samples at relatively low temperature using chlorine gas generated from the reaction between KMnO4 and HCl has been investigated. The effects of chlorination soaking time, potassium permanganate (KMnO4) to hydrochloric acid (HCl) molar ratio and aluminium powder catalyst in chlorine gas generation on titanium extraction from nitrided Malaysian ilmenite were examined. The low-iron nitrided Malaysian ilmenite contained titanium oxycarbonitride (TiOxCyNz) after carbothermal reduction and nitridation with subsequent leaching. Chlorination process was performed at 500°C for 30 - 60 minutes. Statistical analysis of the data was done by Design of Experiment (DOE) to identify the significant variables and their interactions. The results achieved in this study showed that the highest extent of chlorination was about 98.34% at 500°C for 60 minutes. The lowest extent of chlorination was about 68.51% obtained in KMnO4 to HCl molar ratio of 2.0 and 0.35 g of aluminium powder. The chlorinated titanium oxycarbonitride powders and TiCl4 solutions were analyzed by X-ray diffraction (XRD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. The purpose of this study was to explore the relationship between the processing parameters on extracting titanium via pyrometallurgical technique.

Sequential and Simultaneous Applications of UV and Chlorine for Adenovirus Inactivation.

PubMed

Rattanakul, Surapong; Oguma, Kumiko; Takizawa, Satoshi

2015-09-01

Adenoviruses are water-borne human pathogens with high resistance to UV disinfection. Combination of UV treatment and chlorination could be an effective approach to deal with adenoviruses. In this study, human adenovirus 5 (HAdV-5) was challenged in a bench-scale experiment by separate applications of UV or chlorine and by combined applications of UV and chlorine in either a sequential or simultaneous manner. The treated samples were then propagated in human lung carcinoma epithelial cells to quantify the log inactivation of HAdV-5. When the processes were separate, a fluence of 100 mJ/cm(2) and a CT value of 0.02 mg min/L were required to achieve 2 log inactivation of HAdV-5 by UV disinfection and chlorination, respectively. Interestingly, synergistic effects on the HAdV-5 inactivation rates were found in the sequential process of chlorine followed by UV (Cl2-UV) (p < 0.05, ANCOVA) in comparison to the separate processes or the simultaneous application of UV/Cl2. This implies that a pretreatment with chlorine may increase the sensitivity of the virus to the subsequent UV disinfection. In conclusion, this study suggests that the combined application of UV and chlorine could be an effective measure against adenoviruses as a multi-barrier approach in water disinfection.

Inhibition of Chlorine-Induced Lung Injury by the Type 4 Phosphodiesterase Inhibitor Rolipram

PubMed Central

Chang, Weiyuan; Chen, Jing; Schlueter, Connie F.; Rando, Roy J.; Pathak, Yashwant V.; Hoyle, Gary W.

2012-01-01

Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole body exposure, 228–270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1 h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. PMID:22763362

Regioselective electrochemical reduction of 2,4-dichlorobiphenyl - Distinct standard reduction potentials for carbon-chlorine bonds using convolution potential sweep voltammetry

NASA Astrophysics Data System (ADS)

Muthukrishnan, A.; Sangaranarayanan, M. V.; Boyarskiy, V. P.; Boyarskaya, I. A.

2010-04-01

The reductive cleavage of carbon-chlorine bonds in 2,4-dichlorobiphenyl (PCB-7) is investigated using the convolution potential sweep voltammetry and quantum chemical calculations. The potential dependence of the logarithmic rate constant is non-linear which indicates the validity of Marcus-Hush theory of quadratic activation-driving force relationship. The ortho-chlorine of the 2,4-dichlorobiphenyl gets reduced first as inferred from the quantum chemical calculations and bulk electrolysis. The standard reduction potentials pertaining to the ortho-chlorine of 2,4-dichlorobiphenyl and that corresponding to para chlorine of the 4-chlorobiphenyl have been estimated.

Behavior of chlorine during coal pyrolysis

USGS Publications Warehouse

Shao, D.; Hutchinson, E.J.; Cao, H.; Pan, W.-P.; Chou, C.-L.

1994-01-01

The behavior of chlorine in Illinois coals during pyrolysis was evaluated by combined thermo-gravimetry-Fourier transform infrared spectroscopy-ion chromatography (TG-FTIR-IC) techniques. It was found that more than 90% of chlorine in Illinois coals (IBC-103, 105, 106, and 109) was liberated as HCl gas during pyrolysis from 300 to 600??C, with the rate reaching a maximum at 440 ??C. Similarity of the HCl and NH3 release profiles during pyrolysis of IBC-109 supports the hypothesis that the chlorine in coal may be associated with nitrogen and the chlorine is probably bonded to the basic nitrogen sites on the inner walls of coal micropores. ?? 1994 American Chemical Society.

Chlorination and chloramination of aminophenols in aqueous solution: oxidant demand and by-product formation.

PubMed

Mehrez, O Abou; Dossier-Berne, F; Legube, B

2015-01-01

Chlorination and monochloramination of aminophenols (AP) were carried out in aqueous solution at 25°C and at pH 8.5. Oxidant demand and disinfection by-product formation were determined in excess of oxidant. Experiments have shown that chlorine consumption of AP was 40-60% higher than monochloramine consumption. Compared with monochloramination, chlorination of AP formed more chloroform and haloacetic acids (HAA). Dichloroacetic acid was the major species of HAA. Chloroform and HAA represented, respectively, only 1-8% and 14-15% of adsorbable organic halides (AOX) by monochloramination but up to 29% and 39% of AOX by chlorination.

Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

PubMed Central

Hiraishi, A; Furuhata, K; Matsumoto, A; Koike, K A; Fukuyama, M; Tabuchi, K

1995-01-01

Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus. PMID:7793931

Chlorination and oxidation of sulfonamides by free chlorine: Identification and behaviour of reaction products by UPLC-MS/MS.

PubMed

Gaffney, Vanessa de Jesus; Cardoso, Vitor Vale; Benoliel, Maria João; Almeida, Cristina M M

2016-01-15

Sulfonamides (SAs) are one class of the most widely used antibiotics around the world and have been frequently detected in municipal wastewater and surface water in recent years. Their transformation in waste water treatment plants (WWTP) and in water treatment plants (WTP), as well as, their fate and transport in the aquatic environment are of concern. The reaction of six sulfonamides (sulfamethoxazole, sulfapyridine, sulfamethazine, sulfamerazine, sulfathiazole and sulfadiazine) with free chlorine was investigated at a laboratory scale in order to identify the main chlorination by-products. A previously validated method, liquid chromatography/mass spectrometry, was used to analyse SAs and their chlorination by-products. At room temperature, pH 6-7, reaction times of up to 2 h and an initial concentration of 2 mg/L of free chlorine, the majority of SAs suffered degradation of around 65%, with the exception of sulfamethoxazole and sulfathiazole (20%). The main reaction of SAs with free chlorine occurred in the first minute. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and fresh water organisms. First quarterly progress report, April 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerra, C.R.; DelMonaco, J.L.; Singletary, J.H.

1979-01-01

The biological evaluation program incorporates three types of experimental tests: acute (96 hour) toxicity studies; behavioral (avoidance) response studies; and physiological (cough) response studies. In addition, specimens used in testing are examined for physical damage resulting from exposure to chlorine or ozoen. The objective of the acute (96 hour) toxicity study is to determine the respective lethal levels (LC/sub 50/) of chlorinated and ozonated waters. The objective of the behavioral (avoidance) response study is to determine what (if any) concentrations of ozone and of chlorine will be avoided. The objective of physiological (cough) response study is to determine what concentrationsmore » of ozone and of chlorine are physiologically detected. Ozonated and chlorinated waters were evaluated in all studies for both the addition of increased temperature and without it. Results indicate that ozone is less toxic than chlorine under the test conditions used. The lethal levels vary according to species of water quality measurements at Bergen Generating Station, New York are tabulated. (JBG)« less

Recovery of actinides from actinide-aluminium alloys by chlorination: Part III - Chlorination with HCl(g)

NASA Astrophysics Data System (ADS)

Meier, Roland; Souček, Pavel; Walter, Olaf; Malmbeck, Rikard; Rodrigues, Alcide; Glatz, Jean-Paul; Fanghänel, Thomas

2018-01-01

Two steps of a pyrochemical route for the recovery of actinides from spent metallic nuclear fuel are being investigated at JRC-Karlsruhe. The first step consists in electrorefining the fuel in molten salt medium implying aluminium cathodes. The second step is a chlorination process for the separation of actinides (An) from An-Al alloys formed on the cathodes. The chlorination process, in turn, consists of three steps; the distillation of adhered salt (1), the chlorination of An-Al by HCl/Cl2 under formation of AlCl3 and An chlorides (2), and the subsequent sublimation of AlCl3 (3). In the present work UAl2, UAl3, NpAl2, and PuAl2 were chlorinated with HCl(g) in a temperature range between 300 and 400 °C forming UCl4, NpCl4 or PuCl3 as the major An containing phases, respectively. Thermodynamic calculations were carried out to support the experimental work. The results showed a high chlorination efficiency for all used starting materials and indicated that the sublimation step may not be necessary when using HCl(g).

Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

PubMed

Hiraishi, A; Furuhata, K; Matsumoto, A; Koike, K A; Fukuyama, M; Tabuchi, K

1995-06-01

Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus.

The role and function of chlorine in the preparation of high-ratio cake flour.

PubMed

Gough, B M; Whitehouse, M E; Greenwood, C T

1978-01-01

The literature on the role of chlorine treatment of flour for use in high-ratio cake production is discussed in relation to current knowledge of cereal chemistry and cake technology. A brief perspective of the present use of chlorine in high-ratio cake flours is included. Investigations of the uptake of gaseous chlorine by flour and its distribution among and chemical action upon the major flour components (water, protein, lipid, and carbohydrate) are assessed. The physical effects of chlorination as demonstrated by experiments with batters and cakes and by physicochemical observations of flour and its fractions are also considered. The characteristics of the starch in flour appear to be critical in high-ratio cakes. Chlorine treatment modifies the gelatinization behavior of the starch granules yet does not change their gelatinization temperature not is there evidence of chemical attack upon the starch molecules. Therefore, it is suggested that chlorine effects the necessary changes in starch behavior by reacting with the noncarbohydrate surface contaminants on the granules. Alternative methods of improving high-ratio cake flours are mentioned, particularly heat-treatment processes.

Interactions of chlorine plasmas with silicon chloride-coated reactor walls during and after silicon etching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khare, Rohit; Srivastava, Ashutosh; Donnelly, Vincent M.

2012-09-15

The interplay between chlorine inductively coupled plasmas (ICP) and reactor walls coated with silicon etching products has been studied in situ by Auger electron spectroscopy and line-of-sight mass spectrometry using the spinning wall method. A bare silicon wafer mounted on a radio frequency powered electrode (-108 V dc self-bias) was etched in a 13.56 MHz, 400 W ICP. Etching products, along with some oxygen due to erosion of the discharge tube, deposit a Si-oxychloride layer on the plasma reactor walls, including the rotating substrate surface. Without Si-substrate bias, the layer that was previously deposited on the walls with Si-substrate biasmore » reacts with Cl-atoms in the chlorine plasma, forming products that desorb, fragment in the plasma, stick on the spinning wall and sometimes react, and then desorb and are detected by the mass spectrometer. In addition to mass-to-charge (m/e) signals at 63, 98, 133, and 168, corresponding to SiCl{sub x} (x = 1 - 4), many Si-oxychloride fragments with m/e = 107, 177, 196, 212, 231, 247, 275, 291, 294, 307, 329, 345, 361, and 392 were also observed from what appear to be major products desorbing from the spinning wall. It is shown that the evolution of etching products is a complex 'recycling' process in which these species deposit and desorb from the walls many times, and repeatedly fragment in the plasma before being detected by the mass spectrometer. SiCl{sub 3} sticks on the walls and appears to desorb for at least milliseconds after exposure to the chlorine plasma. Notably absent are signals at m/e = 70 and 72, indicating little or no Langmuir-Hinshelwood recombination of Cl on this surface, in contrast to previous studies done in the absence of Si etching.« less

Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsargorodska, Anna; Cartron, Michaël L.; Vasilev, Cvetelin

Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed formore » self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules.« less

Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

DOE PAGES

Tsargorodska, Anna; Cartron, Michaël L.; Vasilev, Cvetelin; ...

2016-09-30

Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed formore » self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules.« less

Ecogenomics of microbial communities in bioremediation of chlorinated contaminated sites

PubMed Central

Maphosa, Farai; Lieten, Shakti H.; Dinkla, Inez; Stams, Alfons J.; Smidt, Hauke; Fennell, Donna E.

2012-01-01

Organohalide compounds such as chloroethenes, chloroethanes, and polychlorinated benzenes are among the most significant pollutants in the world. These compounds are often found in contamination plumes with other pollutants such as solvents, pesticides, and petroleum derivatives. Microbial bioremediation of contaminated sites, has become commonplace whereby key processes involved in bioremediation include anaerobic degradation and transformation of these organohalides by organohalide respiring bacteria and also via hydrolytic, oxygenic, and reductive mechanisms by aerobic bacteria. Microbial ecogenomics has enabled us to not only study the microbiology involved in these complex processes but also develop tools to better monitor and assess these sites during bioremediation. Microbial ecogenomics have capitalized on recent advances in high-throughput and -output genomics technologies in combination with microbial physiology studies to address these complex bioremediation problems at a system level. Advances in environmental metagenomics, transcriptomics, and proteomics have provided insights into key genes and their regulation in the environment. They have also given us clues into microbial community structures, dynamics, and functions at contaminated sites. These techniques have not only aided us in understanding the lifestyles of common organohalide respirers, for example Dehalococcoides, Dehalobacter, and Desulfitobacterium, but also provided insights into novel and yet uncultured microorganisms found in organohalide respiring consortia. In this paper, we look at how ecogenomic studies have aided us to understand the microbial structures and functions in response to environmental stimuli such as the presence of chlorinated pollutants. PMID:23060869

THE ROLE OF CHLORINE IN DIOXIN FORMATION

EPA Science Inventory

There is poor correlation between total chlorine in waste streams and formation of polychlorinated dibenzodioxin and polychlorinated dibenzofuran (PCDD/F) during waste combustion. This is because the active chlorine (Cl) species are strongly dependent upon combustion conditions. ...

Guidance Protocol: Application of Nucleic Acid-Based Tools for Monitoring Monitored Natural Attenuation (MNA), Biostimulation, and Bioaugmentation at Chlorinated Solvent Sites

DTIC Science & Technology

2011-02-01

Reductive dechlorination is a promising process for biodegradation of chlorinated solvents. The successful field evaluation and implementation of the...population. These specialized bacteria use the chlorinated ethenes as electron acceptors and gain energy for growth from the reductive...This guidance protocol addresses the use of MBTs to quantitatively assess the Dhc population at chlorinated ethene sites and aims at providing

Method for the synthesis of chlorosilanes

DOEpatents

Wheeler, D.R.; Pollagi, T.P.

1999-08-17

A novel method is described for the synthesis of chlorinated or partially chlorinated organosilanes and organopolysilanes. The chlorination is effected by contacting an organosilanes or organopolysilanes with anhydrous CuCl{sub 2} in a nonpolar alkane solvent, preferably pentane or hexadecane, without the use of a catalyst. Copper metal, which is easily filtered, is a reaction product. The filtrate containing the chlorinated organosilane or organopolysilane can be used directly as a reactant to produce, for example, aminoorganosilanes.

Method for the synthesis of chlorosilanes

DOEpatents

Wheeler, David R.; Pollagi, Timothy P.

1999-01-01

A novel method for the synthesis of chlorinated or partially chlorinated organosilanes and organopolysilanes. The chlorination is effected by contacting an organosilanes or organopolysilanes with anhydrous CuCl.sub.2 in a nonpolar alkane solvent, preferably pentane or hexadecane, without the use of a catalyst. Copper metal, which is easily filtered, is a reaction product. The filtrate containing the chlorinated organosilane or organopolysilane can be used directly as a reactant to produce, for example, aminoorganosilanes.

Evidence for strong, widespread chlorine radical chemistry associated with pollution outflow from continental Asia

PubMed Central

Baker, Angela K.; Sauvage, Carina; Thorenz, Ute R.; van Velthoven, Peter; Oram, David E.; Zahn, Andreas; Brenninkmeijer, Carl A. M.; Williams, Jonathan

2016-01-01

The chlorine radical is a potent atmospheric oxidant, capable of perturbing tropospheric oxidative cycles normally controlled by the hydroxyl radical. Significantly faster reaction rates allow chlorine radicals to expedite oxidation of hydrocarbons, including methane, and in polluted environments, to enhance ozone production. Here we present evidence, from the CARIBIC airborne dataset, for extensive chlorine radical chemistry associated with Asian pollution outflow, from airborne observations made over the Malaysian Peninsula in winter. This region is known for persistent convection that regularly delivers surface air to higher altitudes and serves as a major transport pathway into the stratosphere. Oxidant ratios inferred from hydrocarbon relationships show that chlorine radicals were regionally more important than hydroxyl radicals for alkane oxidation and were also important for methane and alkene oxidation (>10%). Our observations reveal pollution-related chlorine chemistry that is both widespread and recurrent, and has implications for tropospheric oxidizing capacity, stratospheric composition and ozone chemistry. PMID:27845366

Atomically precise edge chlorination of nanographenes and its application in graphene nanoribbons

PubMed Central

Tan, Yuan-Zhi; Yang, Bo; Parvez, Khaled; Narita, Akimitsu; Osella, Silvio; Beljonne, David; Feng, Xinliang; Müllen, Klaus

2013-01-01

Chemical functionalization is one of the most powerful and widely used strategies to control the properties of nanomaterials, particularly in the field of graphene. However, the ill-defined structure of the present functionalized graphene inhibits atomically precise structural characterization and structure-correlated property modulation. Here we present a general edge chlorination protocol for atomically precise functionalization of nanographenes at different scales from 1.2 to 3.4 nm and its application in graphene nanoribbons. The well-defined edge chlorination is unambiguously confirmed by X-ray single-crystal analysis, which also discloses the characteristic non-planar molecular shape and detailed bond lengths of chlorinated nanographenes. Chlorinated nanographenes and graphene nanoribbons manifest enhanced solution processability associated with decreases in the optical band gap and frontier molecular orbital energy levels, exemplifying the structure-correlated property modulation by precise edge chlorination. PMID:24212200

Effects of short-chain chlorinated paraffins on soil organisms.

PubMed

Bezchlebová, Jitka; Cernohlávková, Jitka; Kobeticová, Klára; Lána, Jan; Sochová, Ivana; Hofman, Jakub

2007-06-01

Despite the fact that chlorinated paraffins have been produced in relatively large amounts, and high concentrations have been found in sewage sludge applied to soils, there is little information on their concentrations in soils and the effect on soil organisms. The aim of this study was to investigate the toxicity of chlorinated paraffins in soils. The effects of short-chain chlorinated paraffins (64% chlorine content) on invertebrates (Eisenia fetida, Folsomia candida, Enchytraeus albidus, Enchytraeus crypticus, Caenorhabditis elegans) and substrate-induced respiration of indigenous microorganisms were studied. Differences were found in the sensitivity of the tested organisms to short-chain chlorinated paraffins. F. candida was identified as the most sensitive organism with LC(50) and EC(50) values of 5733 and 1230 mg/kg, respectively. Toxicity results were compared with available studies and the predicted no effect concentration (PNEC) of 5.28 mg/kg was estimated for the soil environment, based on our data.

A novel microfluidic mixer-based approach for determining inactivation kinetics of Escherichia coli O157:H7 in chlorine solutions.

PubMed

Zhang, Boce; Luo, Yaguang; Zhou, Bin; Wang, Qin; Millner, Patricia D

2015-08-01

Determination of the minimum free chlorine concentration needed to prevent pathogen survival/cross-contamination during produce washing is essential for the development of science-based food safety regulations and practices. Although the trend of chlorine concentration-contact time on pathogen inactivation is generally understood, specific information on chlorine and the kinetics of pathogen inactivation at less than 1.00 s is urgently needed by the produce processing industry. However, conventional approaches to obtain this critical data have been unable to adequately measure very rapid responses. This paper reports our development, fabrication, and test of a novel microfluidic device, and its application to obtain the necessary data on pathogen inactivation by free chlorine in produce wash solution in times as short as 0.10 s. A novel microfluidic mixer with the capability to accurately determine the reaction time and control the chlorine concentration was designed with three inlets for bacterial, chlorine and dechlorinating solutions, and one outlet for effluent collection. The master mold was fabricated on a silicon wafer with microchannels via photopolymerization. Polydimethylsiloxane replicas with patterned microchannels were prototyped via soft lithography. The replicas were further assembled into the micromixer on glass via O2 plasma treatment, and the inlets were connected to a syringe pump for solution delivery. To determine the kinetics of free chlorine on pathogen inactivation, chlorine solutions of varying concentrations were first pumped into the micromixer, together with the addition of bacterial suspension of Escherichia coli O157:H7 through a separate inlet. This was followed by injection of dechlorinating solution to stop the chlorine-pathogen reaction. The effluent was collected and the surviving bacteria cells were enumerated using a modified 'Most Probable Number' method. Free chlorine concentration was determined using a standard colorimetric method. The contact time was experimentally set by adjusting the solution flow rate, and was estimated by computational fluid dynamics modeling. Results showed that 1) pathogen inactivation was significantly affected by free chlorine concentration (P < 0.0001) and subsecond reaction time (P < 0.0001) and their interactions (P < 0.0001); and 2) the current industry practice of using 1.0 mg/L free chlorine will require more than 1.00 s total contact to achieve a 5-log10 reduction in an E. coli O157:H7 population, whereas a 10.0 mg/L free chlorine solution will achieve 5-log10 reduction in as little as 0.25 s. Information obtained from this study will provide critical insight on kinetics of bacterial inactivation for a broad range of sanitizers and produce wash operational conditions, thus facilitating the development and implementation of science-based food safety regulations and practices for improving food safety. Published by Elsevier Ltd.

Trends in chlorinated hydrocarbon levels in Hudson River basin sediments.

PubMed

Bopp, R F; Chillrud, S N; Shuster, E L; Simpson, H J; Estabrooks, F D

1998-08-01

Analysis of sections from dated sediment cores were used to establish geographic distributions and temporal trends of chlorinated hydrocarbon contaminant levels in sediments from natural waters of the Hudson River basin. Radiometric dating was based primarily on the depth distribution of 137(Cs) in the cores and on the occurrence of detectable levels of 7(Be) in surface sediment samples. Eighteen sampling sites included several along the main stem of the Hudson, its major tributaries, and components of the New York/New Jersey (NY/NJ) harbor complex. Drinking-water reservoirs were sampled to place upper limits on atmospheric inputs. Core sections were analyzed for polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT)-derived compounds, chlordane, and dioxins. Sediment concentrations of most contaminants at most sites have decreased significantly since the mid-1960s. The data provide a basinwide perspective on major point-source inputs of PCBs to the upper Hudson River and of 2,3,7,8-tetrachlorodibenzo-p-dioxin and DDT to the lower Passaic River. Evidence was found for significant but poorly characterized sources of PCBs and chlordane to the western NY/NJ harbor, and of highly chlorinated dioxins to the upstream sites on the main stem of the Hudson. The results indicate that analysis of dated sediment samples is a most effective and efficient monitoring tool for the study of large-scale geographic and temporal trends in levels of particle-associated contaminants.

A Novel Method for Profiling and Quantifying Short- and Medium-Chain Chlorinated Paraffins in Environmental Samples Using Comprehensive Two-Dimensional Gas Chromatography-Electron Capture Negative Ionization High-Resolution Time-of-Flight Mass Spectrometry.

PubMed

Xia, Dan; Gao, Lirong; Zheng, Minghui; Tian, Qichang; Huang, Huiting; Qiao, Lin

2016-07-19

Chlorinated paraffins (CPs) are complex technical mixtures containing thousands of isomers. Analyzing CPs in environmental matrices is extremely challenging. CPs have broad, unresolved profiles when analyzed by one-dimensional gas chromatography (GC). Comprehensive two-dimensional GC (GC×GC) can separate CPs with a high degree of orthogonality. A novel method for simultaneously profiling and quantifying short- and medium-chain CPs, using GC×GC coupled with electron capture negative ionization high-resolution time-of-flight mass spectrometry, was developed. The method allowed 48 CP formula congener groups to be analyzed highly selectively in one injection through accurate mass measurements of the [M - Cl](-) ions in full scan mode. The correlation coefficients (R(2)) for the linear calibration curves for different chlorine contents were 0.982 for short-chain CPs and 0.945 for medium-chain CPs. The method was successfully used to determine CPs in sediment and fish samples. By using this method, with enhanced chromatographic separation and high mass resolution, interferences between CP congeners and other organohalogen compounds, such as toxaphene, are minimized. New compounds, with the formulas C9H14Cl6 and C9H13Cl7, were found in sediment and biological samples for the first time. The method was shown to be a powerful tool for the analysis of CPs in environmental samples.

Linking Inflammation and Parkinson Disease: Hypochlorous Acid Generates Parkinsonian Poisons

PubMed Central

Jeitner, Thomas M.; Kalogiannis, Mike; Krasnikov, Boris F.; Gomlin, Irving; Peltier, Morgan R.; Moran, Graham R.

2016-01-01

Inflammation is a common feature of Parkinson Disease and other neurodegenerative disorders. Hypochlorous acid (HOCl) is a reactive oxygen species formed by neutrophils and other myeloperoxidase-containing cells during inflammation. HOCl chlorinates the amine and catechol moieties of dopamine to produce chlorinated derivatives collectively termed chlorodopamine. Here, we report that chlorodopamine is toxic to dopaminergic neurons both in vivo and in vitro. Intrastriatal administration of 90 nmol chlorodopamine to mice resulted in loss of dopaminergic neurons from the substantia nigra and decreased ambulation-results that were comparable to those produced by the same dose of the parkinsonian poison, 1-methyl-4-phenylpyridinium (MPP+). Chlorodopamine was also more toxic to differentiated SH SY5Y cells than HOCl. The basis of this selective toxicity is likely mediated by chlorodopamine uptake through the dopamine transporter, as expression of this transporter in COS-7 cells conferred sensitivity to chlorodopamine toxicity. Pharmacological blockade of the dopamine transporter also mitigated the deleterious effects of chlorodopamine in vivo. The cellular actions of chlorodopamine included inactivation of the α-ketoglutarate dehydrogenase complex, as well as inhibition of mitochondrial respiration. The latter effect is consistent with inhibition of cytochrome c oxidase. Illumination at 670 nm, which stimulates cytochrome c oxidase, reversed the effects of chlorodopamine. The observed changes in mitochondrial biochemistry were also accompanied by the swelling of these organelles. Overall, our findings suggest that chlorination of dopamine by HOCl generates toxins that selectively kill dopaminergic neurons in the substantia nigra in a manner comparable to MPP+. PMID:27026709

Predicting reactivity of model DOM compounds towards chlorine with mediated electrochemical oxidation.

PubMed

de Vera, Glen Andrew; Gernjak, Wolfgang; Radjenovic, Jelena

2017-05-01

Chlorine demand of a water sample depends on the characteristics of dissolved organic matter (DOM). It is an important parameter for water utilities used to assess oxidant and/or disinfectant consumption of source waters during treatment and distribution. In this study, model compounds namely resorcinol, tannic acid, vanillin, cysteine, tyrosine, and tryptophan were used to represent the reactive moieties of complex DOM mixtures. The reactivity of these compounds was evaluated in terms of Cl 2 demand and electron donating capacity (EDC). The EDC was determined by mediated electrochemical oxidation (MEO) which involves the use of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as an electron shuttle. The Cl 2 demand of readily oxidizable compounds (resorcinol, tannic acid, vanillin, and cysteine) was found to correlate well with EDC (R 2  = 0.98). The EDC values (mol e - /mol C) of the model compounds are as follows: 1.18 (cysteine) > 0.77 (resorcinol) > 0.59 (vanillin) > 0.52 (tannic acid) > 0.36 (tryptophan) > 0.19 (tyrosine). To determine the effect of pre-oxidation on EDC, ozone was added (0.1 mol O 3 /mol C) into each model compound solution. Ozonation caused a general decrease in EDC (10-40%), chlorine demand (10-30%), and UV absorbance (10-40%), except for tyrosine which showed both increased UV 275 and EDC. Before and after ozonation, 24 h disinfection byproduct (DBP) formation potential tests (Cl 2 residual = 1.5 mg/L) were conducted to evaluate the use of EDC for DBP formation prediction. The results indicate that there was no significant correlation between the EDC of the model compounds and the formation potentials of adsorbable organic chlorine, trichloromethane, and trichloroacetic acid. This suggests that while EDC correlates with Cl 2 demand, chlorine consumption may not directly translate to DBP formation because oxidation reactions may dominate over substitution reactions. Overall, this study provides useful insights on the reactions of ABTS + and HOCl with model DOM compounds, and highlights the potential application of MEO for rapid determination of Cl 2 demand of a water sample. Copyright © 2017 Elsevier Ltd. All rights reserved.

The stability of chlorinated, brominated, and iodinated haloacetamides in drinking water.

PubMed

Ding, Shunke; Chu, Wenhai; Krasner, Stuart W; Yu, Yun; Fang, Chao; Xu, Bin; Gao, Naiyun

2018-06-13

Haloacetamides (HAMs), a group of nitrogenous disinfection byproducts (N-DBPs), can decompose to form corresponding intermediate products and other DBPs. The stability of ten different HAMs, including two chlorinated, five brominated, and three iodinated species was investigated with and without the presence of chlorine, chloramines, and reactive solutes such as quenching agents. The HAM basic hydrolysis and chlorination kinetics were well described by a second-order kinetics model, including first-order in HAM and hydroxide and first-order in HAM and hypochlorite, respectively, whereas the HAM neutral hydrolysis kinetic was first-order in HAM. Furthermore, HAMs decompose instantaneously when exposed to hypochlorite, which was almost two and nine orders of magnitude faster than HAM basic and neutral hydrolysis, respectively. In general, HAM hydrolysis and chlorination rates both increased with increasing pH and the number of halogens substituted on the methyl group. Moreover, chlorinated HAMs are more unstable than their brominated analogs, followed by the iodinated ones, due to the decrease in the electron-withdrawing inductive effect from chlorine to iodine atom. During hydrolysis, HAMs mainly directly decompose into the corresponding haloacetic acids (HAAs) via a nucleophilic reaction between the carbonyl carbon and hydroxide. For HAM chlorination reactions, hypochlorite reacts with HAMs to form the N-chloro-HAMs (N-Cl-HAMs) via Cl + transfer from chlorine to the amide nitrogen. N-Cl-HAMs can further degrade to form HAAs via hypochlorous acid addition. In contrast, the reactions between chloramines and HAMs were found to be insignificant. Additionally, four common quenching agents, including sodium sulfite, sodium thiosulfate, ascorbic acid, and ammonium chloride, were demonstrated to expedite HAM degradation, whereas ammonium chloride was the least influential among the four. Taft linear free energy relationships were established for both HAM hydrolysis and chlorination reactions, based on which the hydrolysis and chlorination rate constants for three monohaloacetamides were estimated. The hydrolysis and chlorination rates of 13 HAMs decreased in the following order: TCAM > BDCAM > DBCAM > TBAM > DCAM > BCAM > DBAM > CIAM > BIAM > DIAM > MCAM > MBAM > MIAM (where C = chloro, B = bromo, I = iodo, T = tri, D = di, M = mono). Lastly, using the HAM kinetic model established in this study, HAM half-lifes in drinking water distribution systems can be predicted on the basis of pH and residual chlorine concentration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Increased formation of halomethanes during chlorination of chloramphenicol in drinking water by UV irradiation, persulfate oxidation, and combined UV/persulfate pre-treatments.

PubMed

Wenhai, Chu; Tengfei, Chu; Erdeng, Du; Deng, Yang; Yingqing, Guo; Naiyun, Gao

2016-02-01

Ultraviolet/persulfate (UV/PS) has been widely used to generate sulfate radicals for degradation of water organic pollutants in previous studies. However, its impacts on disinfection byproduct formation during post-chlorination of degraded compounds is unclear. The objective of this study was to evaluate the impacts of UV irradiation, PS oxidation, and the combined UV/PS advanced oxidation process (AOP) pre-treatments on halomethane formation during the following chlorination of chloramphenicol (CAP), a model antibiotic commonly found in wastewater-impacted water. Results showed that CAP could be transformed to more trichloromethane (TCM) than monochloromethane (MCM) and dichloromethane (DCM) in the presence of excess chlorine. UV photolysis, PS oxidation and UV/PS AOP all directly decomposed CAP to produce halomethanes (HMs) before post-chlorination. Moreover, UV and UV/PS pre-treatments both enhanced the formation of all the HMs in the subsequent chlorination. PS pre-oxidation decreased the TCM formation during post-chlorination, but increased the yields of MCM, DCM and total HMs. UV pre-irradiation significantly increased the bromide utilization of HMs, whereas UV/PS pre-oxidation decreased the bromine incorporation and utilization of HMs from the chlorination of CAP in a low-bromide water. UV irradiation, PS oxidation, and UV/PS AOP can inactivate pathogens and degrade organic pollutants, but this benefit should be weighed against a potential risk of the increased halomethane formation from degraded organic pollutants with and without post-chlorination. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation.

PubMed

Sorlini, Sabrina; Gialdini, Francesca; Biasibetti, Michela; Collivignarelli, Carlo

2014-05-01

Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of hypochlorous acid exposure on the rejection of salt, polyethylene glycols, boron and arsenic(V) by nanofiltration and reverse osmosis membranes.

PubMed

Do, Van Thanh; Tang, Chuyang Y; Reinhard, Martin; Leckie, James O

2012-10-15

The separation layer of polyamide-based (PA) thin film composite (TFC) membranes can be modified by active chlorine species. The PA-TFC membranes, NF90, BW30 and NF270, were exposed to different concentrations of sodium hypochlorite (NaOCl) at pH 5 for 24 h. Elemental composition obtained from X-ray Photoelectron Spectroscopy (XPS) showed that the chlorine content in the PA layer increased with the chlorine concentrations. Treatment of membranes with 10 ppm Cl increased the membrane hydrophilicity. By contrast, when treated with 1000 ppm Cl or more, the membranes became less hydrophilic. Water permeability values for all 3 membrane types declined with increased chlorine concentrations. Filtration of polyethylene glycols (PEGs) with molecular weights of 200, 400 and 600 Daltons (Da) was performed to investigate the influence of chlorine treatment on membrane molecular weight cut off (MWCO) and rejection by size exclusion. Treatment with 10 and 100 ppm Cl lowered the MWCO while treatment with higher concentrations increased the MWCO. All chlorinated membranes experienced higher NaCl rejection compared to virgin ones. The performance of NF90 was tested with respect to the rejection of inorganic contaminants including boron (H(3)BO(3)) and arsenic (H(2)AsO(4)(-)). The boron rejection results paralleled PEG rejection whereas those for arsenic followed NaCl rejection patterns. The changes in membrane performance due to chlorine treatment were explained in terms of competing mechanisms: membrane tightening, bond cleavage by N-chlorination and chlorination promoted polyamide hydrolysis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chlorination Kinetics of Titanium Nitride for Production of Titanium Tetrachloride from Nitrided Ilmenite

NASA Astrophysics Data System (ADS)

Ahmadi, Eltefat; Rezan, Sheikh Abdul; Baharun, Norlia; Ramakrishnan, Sivakumar; Fauzi, Ahmad; Zhang, Guangqing

2017-10-01

The kinetics of chlorination of titanium nitride (TiN) was investigated in the temperature range of 523 K to 673 K (250 °C to 400 °C). The results showed that the extent of chlorination slightly increased with increasing temperature and decreasing particle size of titanium nitride at constant flow rate of N2-Cl2 gas mixture. At 523 K (250 °C), the extent of chlorination was 85.6 pct in 60 minutes whereas at 673 K (400 °C), it was 97.7 pct investigated by weight loss measurement and confirmed by ICP analyses. The experimental results indicated that a shrinking unreacted core model with mixed-control mechanism governed the chlorination rate. It was observed that the surface chemical reaction of chlorine gas on the surface of TiN particles was rate controlling in the initial stage and, during later stage, internal (pore) diffusion through the intermediate product layer was rate controlling step. Overall the process follows the mixed-control model incorporating both chemical reaction and internal diffusion control. The activation energy for the chlorination of TiN was found to be about 10.97 kJ mol-1. In processing TiCl4 from TiN and TiO0.02C0.13N0.85, the solids involved in the chlorination process were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectrometer (EDX). The SEM/EDX results demonstrated the consumption of TiN particles with extent of chlorination that showed shrinking core behavior.

Mechanistic Aspects of Adenovirus Serotype 2 Inactivation with Free Chlorine ▿ †

PubMed Central

Page, Martin A.; Shisler, Joanna L.; Mariñas, Benito J.

2010-01-01

Free chlorine is an effective disinfectant for controlling adenoviruses in drinking water, but little is known about the underlying inactivation mechanisms. The objective of this study was to elucidate the molecular components of adenovirus type 2 (Ad2) targeted by free chlorine during the inactivation process. The effects of free chlorine treatment on several Ad2 molecular components and associated life cycle events were compared to its effect on the ability of adenovirus to complete its life cycle, i.e., viability. Free chlorine treatment of Ad2 virions did not impair their ability to interact with monoclonal antibodies specific for hexon and fiber proteins of the Ad2 capsid, as measured by enzyme-linked immunosorbent assays, nor did it impair their interaction with recombinant, purified Coxsackie-adenovirus receptor (CAR) proteins in vitro. Free chlorine-treated Ad2 virions also retained their ability to bind to CAR receptors on A549 cell monolayers, despite being unable to form plaques, suggesting that free chlorine inactivates Ad2 by inhibiting a postbinding event of the Ad2 life cycle. DNA isolated from Ad2 virions that had been inactivated by free chlorine was able to be amplified by PCR, indicating that genome damage was not the cause of inactivation. However, inactivated Ad2 virions were unable to express E1A viral proteins during infection of A549 host cells, as measured by using immunoblotting. Collectively, these results indicate that free chlorine inactivates adenovirus by damaging proteins that govern life cycle processes occurring after host cell attachment, such as endocytosis, endosomal lysis, or nuclear delivery. PMID:20305026

Potential Precursor Compounds for Chlorohydrocarbons Detected in Gale Crater, Mars, by the SAM Instrument Suite on the Curiosity Rover

NASA Technical Reports Server (NTRS)

Miller, Kristen E.; Eigenbrode, Jennifer L.; Freissinet, Caroline; Glavin, Daniel P.; Kotrc, Benjamin; Francois, Pascaline; Summons, Roger E.

2016-01-01

The detection of chlorinated organic compounds in near-surface sedimentary rocks by the Sample Analysis at Mars (SAM) instrument suite aboard the Mars Science Laboratory Curiosity rover represents an important step toward characterizing habitable environments on Mars. However, this discovery also raises questions about the identity and source of their precursor compounds and the processes by which they become chlorinated. Here we present the results of analog experiments, conducted under conditions similar to SAM gas chromatography-mass spectrometry analyses, in which we pyrolyzed potential precursor compounds in the presence of various Cl salts and Fe oxides that have been identified in Martian sediments. While chloromethanes could not be unambiguously identified, 1,2-dichloropropane (1,2-DCP), which is one of the chlorinated compounds identified in SAM data, is formed from the chlorination of aliphatic precursors. Additionally, propanol produced more 1,2-DCP than nonfunctionalized aliphatics such as propane or hexanes. Chlorinated benzenes ranging from chlorobenzene to hexachlorobenzene were identified in experiments with benzene carboxylic acids but not with benzene or toluene. Lastly, the distribution of chlorinated benzenes depended on both the substrate species and the nature and concentration of the Cl salt. Ca and Mg perchlorate, both of which release O2 in addition to Cl2 and HCl upon pyrolysis, formed less chlorobenzene relative to the sum of all chlorinated benzenes than in experiments with ferric chloride. FeCl3, a Lewis acid, catalyzes chlorination but does not aid combustion. Accordingly, both the precursor chemistry and sample mineralogy exert important controls on the distribution of chlorinated organics.

Transformation mechanism of benzophenone-4 in free chlorine promoted chlorination disinfection.

PubMed

Xiao, Ming; Wei, Dongbin; Yin, Junxia; Wei, Guohua; Du, Yuguo

2013-10-15

The UV-filter BP-4 (2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) has been frequently observed in the environment, showing high potentials to invade drinking water, swimming water, or wastewater reclamation treatment systems. With the help of high performance liquid chromatography-high resolution mass spectrometry and nuclear magnetic resonance spectroscopy, 10 new products from free chlorine-promoted BP-4 disinfection have been disclosed and their possible transformation routes have been investigated. The first route is chlorine substitution of BP-4 and its transformation products, forming mono-, di-, and tri-chlorinated BP-4 analogs. The second is Baeyer-Villiger-Type oxidation, converting diphenyl ketone to phenyl ester derivatives. The third is ester hydrolysis, generating corresponding phenolic and benzoic products. The fourth is decarboxylation, replacing the carboxyl group by chloride in the benzoic-type intermediate. The fifth is desulfonation, degrading the sulfonic group through an alternative chlorine substitution on the benzene ring. Orthogonal experiments have been established to investigate the species transformed from BP-4 at different pH values and free available chlorine (FAC) dosages. The reaction pathways are strongly dependent on pH conditions, while an excessive amount of FAC eliminates BP-4 to the smaller molecules. The initial transformation of BP-4 in chlorination system follows pseudo-first-order kinetics, and its half-lives ranged from 7.48 s to 1.26 × 10(2) s. More importantly, we have observed that the FAC-treated BP-4 aqueous solution might increase the genotoxic potentials due to the generation of chlorinated disinfection by-products. Copyright © 2013 Elsevier Ltd. All rights reserved.

Catalysis of copper corrosion products on chlorine decay and HAA formation in simulated distribution systems.

PubMed

Zhang, Hong; Andrews, Susan A

2012-05-15

This study investigated the effect of copper corrosion products, including Cu(II), Cu(2)O, CuO and Cu(2)(OH)(2)CO(3), on chlorine degradation, HAA formation, and HAA speciation under controlled experimental conditions. Chlorine decay and HAA formation were significantly enhanced in the presence of copper with the extent of copper catalysis being affected by the solution pH and the concentration of copper corrosion products. Accelerated chlorine decay and increased HAA formation were observed at pH 8.6 in the presence of 1.0 mg/L Cu(II) compared with that observed at pH 6.6 and pH 7.6. Further investigation of chlorine decay in the presence of both Suwannee River NOM and Cu(II) indicated that an increased reactivity of NOM with dissolved and/or solid surface-associated Cu(II), rather than chlorine auto-decomposition, was a primary reason for the observed rapid chlorine decay. Copper corrosion solids [Cu(2)O, CuO, Cu(2)(OH)(2)CO(3)] exhibited catalytic effects on both chlorine decay and HAA formation. Contrary to the results observed when in the absence of copper corrosion products, DCAA formation was consistently predominant over other HAA species in the presence of copper corrosion products, especially at neutral and high pH. This study improves the understanding for water utilities and households regarding chlorine residuals and HAA concentrations in distribution systems, in particular once the water reaches domestic plumbing where copper is widely used. Copyright © 2012 Elsevier Ltd. All rights reserved.

New Polytetrahydrofuran Graft Copolymers.

DTIC Science & Technology

1979-03-15

chioroprene) , chiorobutyl - ~~~~~ rubber , bromobutyl rubber , chlorinated EPDM , chlorinated poly(buta— diene) and chlorinated butadiene styrene copolymer...bromobutyl rubber , which after dehalogenation is unstable with respect to conjugated dienes, the yields of graft copolymer are low. With poly(chloroprerte

40 CFR 261.31 - Hazardous wastes from non-specific sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... free radical catalyzed processes. These chlorinated aliphatic hydrocarbons are those having carbon... spent desiccant wastes from the production of certain chlorinated aliphatic hydrocarbons, by free radical catalyzed processes. These chlorinated aliphatic hydrocarbons are those having carbon chain...

40 CFR 261.31 - Hazardous wastes from non-specific sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... free radical catalyzed processes. These chlorinated aliphatic hydrocarbons are those having carbon... spent desiccant wastes from the production of certain chlorinated aliphatic hydrocarbons, by free radical catalyzed processes. These chlorinated aliphatic hydrocarbons are those having carbon chain...

40 CFR 63.8190 - What emission limitations must I meet?

Code of Federal Regulations, 2010 CFR

2010-07-01

... ton of chlorine produced) from all by-product hydrogen streams and all end box ventilation system... chlorine produced (6.59 × 10−5 pounds of mercury per ton of chlorine produced) from all by-product hydrogen...

IDENTIFICATION OF NEW DISINFECTION BY-PRODUCTS IN DRINKING WATER

EPA Science Inventory

Due to concern over the potential adverse health effects of trihalomethanes (THMs) and other chlorinated by-products in chlorinated drinking water, alternative disinfectants are being explored. Ozone, chlorine dioxide, and chloramine are popular alternatives, as they produce low...

Transformation of methylparaben during water chlorination: Effects of bromide and dissolved organic matter on reaction kinetics and transformation pathways.

PubMed

Yoom, Hoonsik; Shin, Jaedon; Ra, Jiwoon; Son, Heejong; Ryu, Dongchoon; Kim, Changwon; Lee, Yunho

2018-09-01

The reaction kinetics, products, and pathways of methylparaben (MeP) during water chlorination with and without bromide (Br - ) were investigated to better understand the fate of parabens in chlorinated waters. During the chlorination of MeP-spiked waters without Br - , MeP was transformed into mono-Cl-MeP and di-Cl-MeP with apparent second-order rate constants (k app ) of 64M -1 s -1 and 243M -1 s -1 at pH7, respectively, while further chlorination of di-Cl-MeP was relatively slower (k app =1.3M -1 s -1 at pH7). With increasing Br - concentration, brominated MePs, such as mono-Br-MeP, Br-Cl-MeP, and di-Br-MeP, became major transformation products. The di-halogenated MePs (di-Cl-MeP, Br,Cl-MeP, and di-Br-MeP) showed relatively low reactivity to chlorine at pH7 (k app =1.3-4.6M -1 s -1 ) and bromine (k app =32-71M -1 s -1 ), which explains the observed high stability of di-halogenated MePs in chlorinated waters. With increasing pH from 7 to 8.5, the transformation of di-halogenated MePs was further slowed due to the decreasing reactivity of di-MePs to chlorine. The formation of the di-halogenated MePs and their further transformation become considerably faster at Br - concentrations higher than 0.5μM (40μg/L). Nonetheless, the accelerating effect of Br - diminishes in the presence of dissolved organic matter (DOM) extract (Suwannee River humic acid (SRHA)) due to a more rapid consumption of bromine by DOM than chlorine. The effect of Br - on the fate of MeP was less in the tested real water matrices, possibly due to a more rapid bromine consumption by the real water DOM compared to SRHA. A kinetic model was developed based on the determined species-specific second-order rate constants for chlorination/bromination of MeP and its chlorinated and brominated MePs and the transformation pathway information, which could reasonably simulate the transformation of MePs during the chlorination of water in the presence of Br - and selected DOM. Copyright © 2017 Elsevier B.V. All rights reserved.

[Comparative evaluation of health hazards associated with industrial chemicals and their derivates forming during water chlorination].

PubMed

Zholdakova, Z I; Poliakova, E E; Lebedev, A T

2006-01-01

Many industrial chemicals found in waste waters are able to form organochlorine by-products during water disinfection. The transformation of seven model compounds, cyclohexene, n-butanol, diphenylmethane, acetophenone, aniline, 1-methylnaphthalene, and phenylxylylethane during a reaction with active chlorine was studied. Aqueous chlorine and sodium hypochlorite were used as chlorinating agents. The products of the reaction were analyzed by means of chromatomass-spectrometry. A schematic model of diphenylmethane transformation was proposed. Comparative evaluation of hazards associated with the model chemicals and their derivates confirmed that chlorination products can be more toxic and dangerous than the initial compounds, and may possess mutagenic and cancerigenic properties.

A covalent modification for graphene by adamantane groups through two-step chlorination-Grignard reactions

NASA Astrophysics Data System (ADS)

Sun, Xuzhuo; Li, Bo; Lu, Mingxia

2017-07-01

Chemical modification of graphene is a promising approach to manipulate its properties for its end applications. Herein we designed a two-step route through chlorination-Grignard reactions to covalently decorate the surface of graphene with adamantane groups. The chemically modified graphene was characterized by Raman spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Chlorination of graphene occurred rapidly, and the substitution of chlorine atoms on chlorinated graphene by adamantane Grignard reagent afforded adamantane graphene in almost quantitative yield. Adamantane groups were found to be covalently bonded to the graphene carbons. The present two-step procedure may provide an effective and facile route for graphene modification with varieties of organic functional groups.

Batteries for storage of wind-generated energy

NASA Technical Reports Server (NTRS)

Schwartz, H. J.

1973-01-01

Cost effectiveness characteristics of conventional-, metal gas-, and high energy alkali metal-batteries for wind generated energy storage are considered. A lead-acid battery with a power density of 20 to 30 watt/hours per pound is good for about 1500 charge-discharge cycles at a cost of about $80 per kilowatt hour. A zinc-chlorine battery that stores chlorine as solid chlorine hydrate at temperatures below 10 C eliminates the need to handle gaseous chlorine; its raw material cost are low and inexpensive carbon can be used for the chlorine electrode. This system has the best chance to replace lead-acid. Exotic alkali metal batteries are deemed too costly at the present stage of development.

Ab Initio Calculations of Singlet and Triplet Excited States of Chlorine Nitrate and Nitric Acid

NASA Technical Reports Server (NTRS)

Grana, Ana M.; Lee, Timothy J.; Head-Gordon, Martin; Langhoff, Stephen R. (Technical Monitor)

1994-01-01

Ab initio calculations of vertical excitations to singlet and triplet excited states of chlorine nitrate and nitric acid are reported. The nature of the electronic transitions are examined by decomposing the difference density into the sum of detachment and attachment densities. Counterparts for the three lowest singlet excited states of nitric acid survive relatively unperturbed in chlorine nitrate, while other low-lying singlet states of chlorine nitrate appear to be directly dissociative in the ClO chromophore. These results suggest an assignment of the two main peaks in the experimental chlorine nitrate absorption spectrum. In addition, triplet vertical excitations and the lowest optimized triplet geometries of both molecules are studied.

Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig, S.

Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be usedmore » for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of three to five times, leading to a more rapid clean-up of the DNAPL zone. The most favored electron donor to add is one which partitions well with the chlorinated solvent or can be concentrated near it. Unfortunately, an ideal electron donor, such as vegetable oil, is difficult to introduce and mix with DNAPL in the ground, doing this properly remains an engineering challenge. Numerical model studies have indicated that several factors may significantly influence the rate and extent of enhancement, including the inhibitory effects of PCE and cDCE, the level of ED concentration, DNAPL configuration, and competition for ED. Such factors need to be considered when contemplating engineered DNAPL bioremediation. Pseudomonas stuzeri KC is an organism that transforms CT to carbon dioxide and chloride without the formation of the hazardous intermediate, chloroform. This is accomplished by production and secretion of a molecule called PDTC. This study was direct ed towards determining how PDTC works. Cu (II) at a ratio of 1:1 Cu to PDTC was found to result in the most rapid CT transformation, confirming that the PDTC-Cu complex is both a reactant and a catalyst in CT transformation. CT degradation requires that the PDTC be in a reduced form, which is generated by contact with cell components. Fe(II) inhibits CT transformation by PDTC. Studies indicated that this inhibition is enhanced by some compound or factor in the supernatant with molecular weight greater than 10,000 Da. We have made progress in determining what this factor might be, but have not yet been able to identify it. In related studies, we found that CT transformation by another organism, Shewanella oneidensis MR1, also involves an excreted factor, but this factor is different from PDTC and results in chloroform transformation as an intermediate. Our studies have indicated that this factor is similar to vitamin K2, and we have also confirmed that vitamin K2 does transform C T into chloroform.« less

Advanced Valve Technology. Volume 2. Materials Compatibility and Liquid Propellant Study

DTIC Science & Technology

1967-11-01

hydrogen fluoride and hydrogen chloride, which are formed by the reaction of chlorine trifluoride with water. Aluminum alloys, 18-8 stainless steels... CHLORINE TRIFLUORIDE (CTF) (ClF3) 1-68 CHLORINE PENTAFLUORIDE 1-72 OXYGEN DIFLUORIDE (OF2) 1-74 PERCHLORYL FLUORIDE (PF) (FC103 or C103F) 1-79...enclosures refer to the Propellant Rating Chart, Page 1-11. 1-67 SPACE STORABLE PROPELLANTS (Continued) OXIDIZERS CHLORINE TRIFLUORIDE (CTF) (CIF 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Moonsoo; Kim, Jongmin; Cho, Jaehee

Graphical abstract: The presence of Chlorine in the outer surface resulted in a highly electro-negative surface states and an increase in the vacuum energy level. - Highlights: • We investigated the influence of chlorine surface treatment on ITO properties. • Chlorination induced the change of the electro-static potential in the outer surface. • Chlorine electro-chemical treatment of ITO is a simple, fast and effective technique. - Abstract: In this work, we investigate the influence of a chlorine-based electro-chemical surface treatment on the characteristics of indium tin oxide (ITO) including the work function, chemical composition, and phase transition. The treated ITOsmore » were characterized using X-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy (UPS), 4-point probe measurements, and grazing incidence X-ray diffraction (GI-XRD). We confirmed a change of the chemical composition in the near-surface region of the ITO and the formation of indium-chlorine (In-Cl) bonds and surface dipoles (via XPS). In particular, the change of the electro-static potential in the outer surface was caused by chlorination. Due to the vacuum-level shift after the electro-chemical treatment in a dilute hydrochloric acid, the ITO work function was increased by ∼0.43 eV (via UPS); furthermore, the electro-negativity of the chlorine anions attracted electrons to emit them from the hole transport layer (HTL) to the ITO anodes, resulting in an increase of the hole-injection efficiency.« less

Investigating the management performance of disinfection analysis of water distribution networks using data mining approaches.

PubMed

Zounemat-Kermani, Mohammad; Ramezani-Charmahineh, Abdollah; Adamowski, Jan; Kisi, Ozgur

2018-06-13

Chlorination, the basic treatment utilized for drinking water sources, is widely used for water disinfection and pathogen elimination in water distribution networks. Thereafter, the proper prediction of chlorine consumption is of great importance in water distribution network performance. In this respect, data mining techniques-which have the ability to discover the relationship between dependent variable(s) and independent variables-can be considered as alternative approaches in comparison to conventional methods (e.g., numerical methods). This study examines the applicability of three key methods, based on the data mining approach, for predicting chlorine levels in four water distribution networks. ANNs (artificial neural networks, including the multi-layer perceptron neural network, MLPNN, and radial basis function neural network, RBFNN), SVM (support vector machine), and CART (classification and regression tree) methods were used to estimate the concentration of residual chlorine in distribution networks for three villages in Kerman Province, Iran. Produced water (flow), chlorine consumption, and residual chlorine were collected daily for 3 years. An assessment of the studied models using several statistical criteria (NSC, RMSE, R 2 , and SEP) indicated that, in general, MLPNN has the greatest capability for predicting chlorine levels followed by CART, SVM, and RBF-ANN. Weaker performance of the data-driven methods in the water distribution networks, in some cases, could be attributed to improper chlorination management rather than the methods' capability.

Assessing the Impact of Chlorinated-Solvent Sites on Metropolitan Groundwater Resources

PubMed Central

Brusseau, Mark L.; Narter, Matthew

2014-01-01

Chlorinated-solvent compounds are among the most common groundwater contaminants in the U.S.A. The majority of the many sites contaminated by chlorinated-solvent compounds are located in metropolitan areas, and most such areas have one or more chlorinated-solvent contaminated sites. Thus, contamination of groundwater by chlorinated-solvent compounds may pose a potential risk to the sustainability of potable water supplies for many metropolitan areas. The impact of chlorinated-solvent sites on metropolitan water resources was assessed for Tucson, AZ, by comparing the aggregate volume of extracted groundwater for all pump-and-treat systems associated with contaminated sites in the region to the total regional groundwater withdrawal. The analysis revealed that the aggregate volume of groundwater withdrawn for the pump-and-treat systems operating in Tucson, all of which are located at chlorinated-solvent contaminated sites, was 20% of the total groundwater withdrawal in the city for the study period. The treated groundwater was used primarily for direct delivery to local water supply systems or for reinjection as part of the pump-and-treat system. The volume of the treated groundwater used for potable water represented approximately 13% of the total potable water supply sourced from groundwater, and approximately 6% of the total potable water supply. This case study illustrates the significant impact chlorinated-solvent contaminated sites can have on groundwater resources and regional potable-water supplies. PMID:24116872

Thermodynamic analysis of the selective chlorination of electric arc furnace dust.

PubMed

Pickles, C A

2009-07-30

The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

Inhibition of chlorine-induced lung injury by the type 4 phosphodiesterase inhibitor rolipram.

PubMed

Chang, Weiyuan; Chen, Jing; Schlueter, Connie F; Rando, Roy J; Pathak, Yashwant V; Hoyle, Gary W

2012-09-01

Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole body exposure, 228-270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. Copyright © 2012 Elsevier Inc. All rights reserved.

Formation of nitrosodimethylamine (NDMA) during chlorine disinfection of wastewater effluents prior to use in irrigation systems.

PubMed

Pehlivanoglu-Mantas, Elif; Hawley, Elisabeth L; Deeb, Rula A; Sedlak, David L

2006-01-01

The probable human carcinogen nitrosodimethylamine (NDMA) is produced when wastewater effluent is disinfected with chlorine. In systems where wastewater effluent is used for landscape or crop irrigation, relatively high chlorine doses (i.e., up to 2,000,mg-min/L) are often used to ensure adequate disinfection and to minimize biofouling in the irrigation system. To assess the formation of NDMA in such systems, samples were collected from several locations in full-scale wastewater treatment systems and their associated irrigation systems. Up to 460 ng/L of NDMA was produced in full-scale systems in which chloramines were formed when wastewater effluent was disinfected with chlorine in the presence of ammonia. Less than 20 ng/L of NDMA was produced in systems that used free chlorine (i.e., HOCl/OCl(-)) for disinfection in the absence of ammonia. The production of NDMA in ammonia-containing systems was correlated with the concentration of NDMA precursors in the wastewater effluent and the overall dose of chlorine applied. Much of the NDMA formation occurred in chlorine contact basins or in storage basins where water that contained chloramines was held after disinfection. When landscape or crop irrigation is practiced with ammonia-containing wastewater effluent, NDMA production can be controlled by use of lower chlorine doses or by application of alternative disinfectants.

Inhibition of chlorine-induced pulmonary inflammation and edema by mometasone and budesonide

PubMed Central

Chen, Jing; Mo, Yiqun; Schlueter, Connie F.; Hoyle, Gary W.

2013-01-01

Chlorine gas is a widely used industrial compound that is highly toxic by inhalation and is considered a chemical threat agent. Inhalation of high levels of chlorine results in acute lung injury characterized by pneumonitis, pulmonary edema, and decrements in lung function. Because inflammatory processes can promote damage in the injured lung, anti-inflammatory therapy may be of potential benefit for treating chemical-induced acute lung injury. We previously developed a chlorine inhalation model in which mice develop epithelial injury, neutrophilic inflammation, pulmonary edema, and impaired pulmonary function. This model was used to evaluate nine corticosteroids for the ability to inhibit chlorine-induced neutrophilic inflammation. Two of the most potent corticosteroids in this assay, mometasone and budesonide, were investigated further. Mometasone or budesonide administered intraperitoneally 1 h after chlorine inhalation caused a dose-dependent inhibition of neutrophil influx in lung tissue sections and in the number of neutrophils in lung lavage fluid. Budesonide, but not mometasone, reduced the levels of the neutrophil attractant CXCL1 in lavage fluid 6 h after exposure. Mometasone or budesonide also significantly inhibited pulmonary edema assessed 1 day after chlorine exposure. Chlorine inhalation resulted in airway hyperreactivity to inhaled methacholine, but neither mometasone nor budesonide significantly affected this parameter. The results suggest that mometasone and budesonide may represent potential treatments for chemical-induced lung injury. PMID:23800689

Gasification Characteristics and Kinetics of Coke with Chlorine Addition

NASA Astrophysics Data System (ADS)

Wang, Cui; Zhang, Jianliang; Jiao, Kexin; Liu, Zhengjian; Chou, Kuochih

2017-10-01

The gasification process of metallurgical coke with 0, 1.122, 3.190, and 7.132 wt pct chlorine was investigated through thermogravimetric method from ambient temperature to 1593 K (1320 °C) in purified CO2 atmosphere. The variations in the temperature parameters that T i decreases gradually with increasing chlorine, T f and T max first decrease and then increase, but both in a downward trend indicated that the coke gasification process was catalyzed by the chlorine addition. Then the kinetic model of the chlorine-containing coke gasification was obtained through the advanced determination of the average apparent activation energy, the optimal reaction model, and the pre-exponential factor. The average apparent activation energies were 182.962, 118.525, 139.632, and 111.953 kJ/mol, respectively, which were in the same decreasing trend with the temperature parameters analyzed by the thermogravimetric method. It was also demonstrated that the coke gasification process was catalyzed by chlorine. The optimal kinetic model to describe the gasification process of chlorine-containing coke was the Šesták Berggren model using Málek's method, and the pre-exponential factors were 6.688 × 105, 2.786 × 103, 1.782 × 104, and 1.324 × 103 min-1, respectively. The predictions of chlorine-containing coke gasification from the Šesták Berggren model were well fitted with the experimental data.

Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

PubMed

Krkošek, Wendy H; Koziar, Stephen A; White, Robert L; Gagnon, Graham A

2011-01-01

High global consumption rates have led to the occurrence of pharmaceutically active compounds (PhACs) in wastewater. The use of chlorine to disinfect wastewater prior to release into the environment may convert PhACs into uncharacterized chlorinated by-products. In this investigation, chlorination of a common pharmaceutical, the antihyperlipidemic agent gemfibrozil, was documented. Gemfibrozil (2,2-dimethyl-5-(2,5-dimethylphenoxy)pentanoic acid) was reacted with sodium hypochlorite and product formation was monitored by gas chromatography-mass spectrometry (GC-MS). The incorporation of one, two or three chlorine atoms into the aromatic region of gemfibrozil was demonstrated using negative-ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Further analysis using (1)H nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as 4'-ClGem (5-(4-chloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid) 4',6'-diClGem (5-(4,6-dichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), and 3',4',6'-triClGem (5-(3,4,6-trichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), products consistent with electrophilic aromatic substitution reactions. The rapid reaction of gemfibrozil with free chlorine at pH conditions relevant to water treatment indicates that a mixture of chlorinated gemfibrozils is likely to be found in wastewater disinfected with chlorine. Copyright © 2010 Elsevier Ltd. All rights reserved.

Inhibition of chlorine-induced pulmonary inflammation and edema by mometasone and budesonide.

PubMed

Chen, Jing; Mo, Yiqun; Schlueter, Connie F; Hoyle, Gary W

2013-10-15

Chlorine gas is a widely used industrial compound that is highly toxic by inhalation and is considered a chemical threat agent. Inhalation of high levels of chlorine results in acute lung injury characterized by pneumonitis, pulmonary edema, and decrements in lung function. Because inflammatory processes can promote damage in the injured lung, anti-inflammatory therapy may be of potential benefit for treating chemical-induced acute lung injury. We previously developed a chlorine inhalation model in which mice develop epithelial injury, neutrophilic inflammation, pulmonary edema, and impaired pulmonary function. This model was used to evaluate nine corticosteroids for the ability to inhibit chlorine-induced neutrophilic inflammation. Two of the most potent corticosteroids in this assay, mometasone and budesonide, were investigated further. Mometasone or budesonide administered intraperitoneally 1h after chlorine inhalation caused a dose-dependent inhibition of neutrophil influx in lung tissue sections and in the number of neutrophils in lung lavage fluid. Budesonide, but not mometasone, reduced the levels of the neutrophil attractant CXCL1 in lavage fluid 6h after exposure. Mometasone or budesonide also significantly inhibited pulmonary edema assessed 1 day after chlorine exposure. Chlorine inhalation resulted in airway hyperreactivity to inhaled methacholine, but neither mometasone nor budesonide significantly affected this parameter. The results suggest that mometasone and budesonide may represent potential treatments for chemical-induced lung injury. © 2013.

Reaction kinetics and transformation of carbadox and structurally related compounds with aqueous chlorine.

PubMed

Shah, Amisha D; Kim, Jae-Hong; Huang, Ching-Hua

2006-12-01

The potential release of carbadox (CDX), a commonly used antibacterial agent in swine husbandry, into water systems is of a concern due to its carcinogenic and genotoxic effects. Until this study, the reactivity of carbadox (possessing quinoxaline N,N'-dioxide and hydrazone moieties) toward aqueous chlorine has yetto be investigated in depth. Chemical reactivity, reaction kinetics, and transformation pathways of carbadox and structurally related compounds with free chlorine under typical water treatment conditions were determined. This study found that only CDX and desoxycarbadox (DCDX), a main metabolite of CDX with no ring N-oxide groups, react rapidly with free chlorine while other structurally related compounds including olaquindox, quindoxin, quinoxaline N-oxide, quinoxaline, and quinoline N-oxide do not. The reaction kinetics of CDX and DCDX with chlorine are highly pH dependent (e.g., the apparent second-order rate constant, kapp, for CDX ranges from 51.8 to 3.15 x 10(4) M(-1)s(-1) at pH 4-11). The high reactivity of CDX and DCDX to chlorine involves deprotonation of their hydrazone N-H moieties where initial chlorine attack results in a reactive intermediate that is further attacked by nucleophiles in the matrix to yield non-chlorinated, hydroxylated, and larger molecular weight byproducts. All of the CDX's byproducts retain their biologically active N-oxide groups, suggesting that they may remain as active antibacterial agents.

Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes.

PubMed

Kong, Xiujuan; Wu, Zihao; Ren, Ziran; Guo, Kaiheng; Hou, Shaodong; Hua, Zhechao; Li, Xuchun; Fang, Jingyun

2018-06-15

Degradation of three lipid regulators, i.e., gemfibrozil, bezafibrate and clofibric acid, by a UV/chlorine treatment was systematically investigated. The chlorine oxide radical (ClO • ) played an important role in the degradation of gemfibrozil and bezafibrate with second-order rate constants of 4.2 (±0.3) × 10 8  M -1  s -1 and 3.6 (±0.1) × 10 7  M -1  s -1 , respectively, whereas UV photolysis and the hydroxyl radical (HO • ) mainly contributed to the degradation of clofibric acid. The first-order rate constants (k') for the degradation of gemfibrozil and bezafibrate increased linearly with increasing chlorine dosage, primarily due to the linear increase in the ClO • concentration. The k' values for gemfibrozil, bezafibrate, and clofibric acid degradation decreased with increasing pH from 5.0 to 8.4; however, the contribution of the reactive chlorine species (RCS) increased. Degradation of gemfibrozil and bezafibrate was enhanced in the presence of Br - , whereas it was inhibited in the presence of natural organic matter (NOM). The presence of ammonia at a chlorine: ammonia molar ratio of 1:1 resulted in decreases in the k' values for gemfibrozil and bezafibrate of 69.7% and 7%, respectively, but led to an increase in that for clofibric acid of 61.8%. Degradation of gemfibrozil by ClO • was initiated by hydroxylation and chlorine substitution on the benzene ring. Then, subsequent hydroxylation, bond cleavage and chlorination reactions led to the formation of more stable products. Three chlorinated intermediates were identified during ClO • oxidation process. Formation of the chlorinated disinfection by-products chloral hydrate and 1,1,1-trichloropropanone was enhanced relative to that of other by-products. The acute toxicity of gemfibrozil to Vibrio fischeri increased significantly when subjected to direct UV photolysis, whereas it decreased when oxidized by ClO • . This study is the first to report the transformation pathway of a micropollutant by ClO • . Copyright © 2018 Elsevier Ltd. All rights reserved.

Association between domestic water hardness, chlorine, and atopic dermatitis risk in early life: A population-based cross-sectional study.

PubMed

Perkin, Michael R; Craven, Joanna; Logan, Kirsty; Strachan, David; Marrs, Tom; Radulovic, Suzana; Campbell, Linda E; MacCallum, Stephanie F; McLean, W H Irwin; Lack, Gideon; Flohr, Carsten

2016-08-01

Domestic water hardness and chlorine have been suggested as important risk factors for atopic dermatitis (AD). We sought to examine the link between domestic water calcium carbonate (CaCO3) and chlorine concentrations, skin barrier dysfunction (increased transepidermal water loss), and AD in infancy. We recruited 1303 three-month-old infants from the general population and gathered data on domestic water CaCO3 (in milligrams per liter) and chlorine (Cl2; in milligrams per liter) concentrations from local water suppliers. At enrollment, infants were examined for AD and screened for filaggrin (FLG) skin barrier gene mutation status. Transepidermal water loss was measured on unaffected forearm skin. CaCO3 and chlorine levels were strongly correlated. A hybrid variable of greater than and less than median levels of CaCO3 and total chlorine was constructed: a baseline group of low CaCO3/low total chlorine (CaL/ClL), high CaCO3/low total chlorine (CaH/ClL), low CaCO3/high total chlorine (CaL/ClH) and high CaCO3/high total chlorine (CaH/ClH). Visible AD was more common in all 3 groups versus the baseline group: adjusted odds ratio (AOR) of 1.87 (95% CI, 1.25-2.80; P = .002) for the CaH/ClL group, AOR of 1.46 (95% CI, 0.97-2.21; P = .07) for the CaL/ClH, and AOR of 1.61 (95% CI, 1.09-2.38; P = .02) for the CaH/ClH group. The effect estimates were greater in children carrying FLG mutations, but formal interaction testing between water quality groups and filaggrin status was not statistically significant. High domestic water CaCO3 levels are associated with an increased risk of AD in infancy. The influence of increased total chlorine levels remains uncertain. An intervention trial is required to see whether installation of a domestic device to decrease CaCO3 levels around the time of birth can reduce this risk. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Request for Available Information on Chlorinated Paraffins Submitted as Pre-Manufacture Notices (PMNs)

EPA Pesticide Factsheets

EPA is requesting new available data on certain chlorinated paraffins in different industries and for different uses, to inform the risk assessments for chlorinated paraffins submitted as Toxic Substances Control Act (TSCA) Premanufacture Notices (PMNs).

MECHANISTIC-BASED DISINFECTION AND DISINFECTION BYPRODUCT MODELS

EPA Science Inventory

We propose developing a mechanistic-based numerical model for chlorine decay and regulated DBP (THM and HAA) formation derived from (free) chlorination; the model framework will allow future modifications for other DBPs and chloramination. Predicted chlorine residual and DBP r...

75 FR 51113 - Chlorinated Isocyanurates From China and Spain

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-18

... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 731-TA-1082 and 1083 (Review)] Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade Commission. ACTION: Scheduling of expedited five-year reviews concerning the antidumping duty orders on chlorinated isocyanurates from China...

IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

EPA Science Inventory

This project evaluated the potential of enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (TCE), cis-and trans-1,2-dichloroethene (DCE), an...

Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

EPA Science Inventory

This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (...

BROMIDE-OXIDANT INTERACTIONS AND THM (TRIHALOMETHANE) FORMATION: A LITERATURE REVIEW

EPA Science Inventory

The review focuses on the interactions, not only of bromide and chlorine, but also of bromide and two common oxidation alternatives to chlorine--chlorine dioxide and monochloramine. The data evaluations include discussions of reaction products, potentials for trihalomethane (THM)...

78 FR 58997 - Chlorinated Isocyanurates From Japan: Initiation of Antidumping Duty Investigation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-25

... From Japan: Initiation of Antidumping Duty Investigation AGENCY: Import Administration, International... (``AD'') petition concerning imports of chlorinated isocyanurates (``chlorinated isos'') from Japan... Japan, dated August 29, 2013 (``Petition''). \\2\\ See First Supplement to the AD Petition, dated...

Bromate formation from the oxidation of bromide in the UV/chlorine process with low pressure and medium pressure UV lamps.

PubMed

Fang, Jingyun; Zhao, Quan; Fan, Chihhao; Shang, Chii; Fu, Yun; Zhang, Xiangru

2017-09-01

When a bromide-containing water is treated by the ultraviolet (UV)/chlorine process, hydroxyl radicals (HO) and halogen radicals such as Cl or Br are formed due to the UV photolysis of free halogens. These reactive species may induce the formation of bromate, which is a probable human carcinogen. Bromate formation in the UV/chlorine process using low pressure (LP) and medium pressure (MP) lamps in the presence of bromide was investigated in the present study. The UV/chlorine process significantly enhanced bromate formation as compared to dark chlorination. The bromate formation was elevated with increasing UV fluence, bromide concentration, and pH values under both LP and MP UV irradiations. It was significantly enhanced at pH 9 compared to those at pH 6 and 7 with MP UV irradiation, while it was slightly enhanced at pH 9 with LP UV. The formation by UV/chlorine process started with the formation of free bromine (HOBr/OBr - ) through the reaction of chlorine and bromide, followed by a subsequent oxidation of free bromine and formation of BrO and bromate by reacting with radicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ozone Temperature Correlations in the Upper Stratosphere as a Measure of Chlorine Content

NASA Technical Reports Server (NTRS)

Stolarski, Richard S.; Douglass, Ann R.; Remsberg, Ellis E.; Livesey, Nathaniel J.; Gille, John C.

2012-01-01

We use data from the Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) for the 1978-1979 period together with data from the Upper Atmosphere Research Satellite Microwave Limb Sounder (UARS MLS) for the years 1993 to 1999, the Aura MLS for the years 2004 to 2011, and the Aura High Resolution Infrared Limb Sounder (HIRDLS) for the years 2005 to 2007 to examine ozone-temperature correlations in the upper stratosphere. Our model simulations indicate that the sensitivity coefficient of the ozone response to temperature (Delta ln(O3)/Delta.(l/T)) decreases as chlorine has increased in the stratosphere and should increase in the future as chlorine decreases. The data are in agreement with our simulation of the past. We also find that the sensitivity coefficient does not change in a constant-chlorine simulation. Thus the change in the sensitivity coefficient depends on the change in chlorine, but not on the change in greenhouse gases. We suggest that these and future data can be used to track the impact of chlorine added to the stratosphere and also to track the recovery of the stratosphere as chlorine is removed under the provisions of the Montreal Protocol.

A COMPREHENSIVE ANALYSIS OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ENVIRONMENTAL RELEASE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buckley, R.; Hunter, C.; Werth, D.

2011-05-10

A train derailment occurred in Graniteville, South Carolina during the early morning of January 6, 2005, and resulted in the release of a large amount of cryogenic pressurized liquid chlorine to the environment in a short time period. A comprehensive evaluation of the transport and fate of the released chlorine was performed, accounting for dilution, diffusion, transport and deposition into the local environment. This involved the characterization of a three-phased chlorine release, a detailed determination of local atmospheric mechanisms acting on the released chlorine, the establishment of atmospheric-hydrological physical exchange mechanisms, and aquatic dilution and mixing. This presentation will providemore » an overview of the models used in determining the total air-to-water mass transfer estimated to have occurred as a result of the roughly 60 tons of chlorine released into the atmosphere from the train derailment. The assumptions used in the modeling effort will be addressed, along with a comparison with available observational data to validate the model results. Overall, model-estimated chlorine concentrations in the airborne plume compare well with human and animal exposure data collected in the days after the derailment.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoyle, Gary W., E-mail: Gary.Hoyle@louisville.edu; Chen, Jing; Schlueter, Connie F.

Chlorine is a commonly used, reactive compound to which humans can be exposed via accidental or intentional release resulting in acute lung injury. Formulations of rolipram (a phosphodiesterase inhibitor), triptolide (a natural plant product with anti-inflammatory properties), and budesonide (a corticosteroid), either neat or in conjunction with poly(lactic:glycolic acid) (PLGA), were developed for treatment of chlorine-induced acute lung injury by intramuscular injection. Formulations were produced by spray-drying, which generated generally spherical microparticles that were suitable for intramuscular injection. Multiple parameters were varied to produce formulations with a wide range of in vitro release kinetics. Testing of selected formulations in chlorine-exposedmore » mice demonstrated efficacy against key aspects of acute lung injury. The results show the feasibility of developing microencapsulated formulations that could be used to treat chlorine-induced acute lung injury by intramuscular injection, which represents a preferred route of administration in a mass casualty situation. - Highlights: • Chlorine causes lung injury when inhaled and is considered a chemical threat agent. • Countermeasures for treatment of chlorine-induced acute lung injury are needed. • Formulations containing rolipram, triptolide, or budesonide were produced. • Formulations with a wide range of release properties were developed. • Countermeasure formulations inhibited chlorine-induced lung injury in mice.« less

Chlorinated river and lake water extract caused oxidative damage, DNA migration and cytotoxicity in human cells.

PubMed

Yuan, Jing; Wu, Xin-Jiang; Lu, Wen-Qing; Cheng, Xiao-Li; Chen, Dan; Li, Xiao-Yan; Liu, Ai-Lin; Wu, Jian-Jun; Xie, Hong; Stahl, Thorsten; Mersch-Sundermann, Volker

2005-01-01

Consumption of chlorinated drinking water is suspected to be associated with adverse health effects, including mutations and cancer. In the present study, the genotoxic potential of water from Donghu lake, Yangtze river and Hanjiang river in Wuhan, an 8-million metropolis in China, was investigated using HepG2 cells and the alkaline version of the comet assay. It could be shown that all water extracts caused dose-dependent DNA migration in concentrations corresponding to dried extracts of 0.167-167 ml chlorinated drinking water per ml medium. To explore whether the intracellular redox status is regulated by chlorinated drinking water, we determined lipid peroxidation (LPO) and depletion of reduced glutathione (GSH). The malondialdehyde (thiobarbituric acid (TBA)-reactive aldehydes) concentration increased after chlorinated drinking water treatment of HepG2 cells in a dose-dependent manner, the GSH content decreased. The activity of lactate dehydrogenase (LDH) increased in chlorinated drinking water treated HepG2 cells indicating cytotoxicity. In accordance with former studies which dealt with in vivo and in vitro micronucleus induction the present study shows that chlorinated drinking water from polluted raw water may entail genetic risks.

Molecular complexes of L-phenylalanine with substituted 1,4-benzoquinones in aqueous medium: Spectral and theoretical investigations

NASA Astrophysics Data System (ADS)

Ganesh, K.; El-Mossalamy, E. H.; Satheshkumar, A.; Balraj, C.; Elango, K. P.

2013-12-01

Various spectral techniques such as UV-Vis, FT-IR, and fluorescence have been employed to investigate the charge transfer interaction of L-phenylalanine (LPA) with substituted 1,4-benzoquinones (MQ1-4). Kinetic and thermodynamic properties of the complexes were determined in aqueous medium at physiological condition (pH = 7). The interaction of MQ1-4 with L-phenylalanine (LPA) was found to proceed through the formation of donor-acceptor complex, yielding a radical anion. The stoichiometry of the complexes was determined by Jobs continuous variation method and was found to be 1:1 in all the cases. Fluorescence quenching studies showed that the interaction between the donor and the acceptors is spontaneous. The results indicated that the progressive replacement of chlorine atom (-I effect) by methoxy group (+M effect) in the quinone decreased the electron acceptor property of the quinone. The order of the experimentally measured association constant of these complexes was well supported by DFT/B3LYP calculations.

ABIOTIC REACTIONS MAY BE THE MOST IMPORTANT MECHANISM IN NATURAL ATTENUATION OF CHLORINATED SOLVENTS

EPA Science Inventory

The EPA Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Ground Water was developed with the assumption that natural biological reductive dechlorination was the only important mechanism for destruction of chlorinated solvents and their reduction ...