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PubMed2006

Transformation of phenol, catechol, guaiacol and syringol exposed to sodium hypochlorite.

Germs, xenobiotics and organic matter that influence the colour, turbidity and organoloeptic properties of water are removed by chlorination. Unfortunately, chlorine oxidants including sodium hypochlorite, used in water treatment induce processes that partly convert the treated compounds to unwanted chlorinated derivatives. The purpose of this work was to analyse the efficiency of transformation of phenol, catechol, guaiacol and syringol exposed to sodium hypochlorite and determine the intermediates formed during oxidative conversion of these compounds. The analysis was performed in aerobic conditions, both in acidic (pH 4.0) and alkaline (pH 8.0) medium. The effectiveness of transformation was slightly higher in acidic in comparison to alkaline conditions. Some chlorophenols, such as 2-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol were determined as the products of phenol conversion. Chlorophenols were also formed during catechol, guaiacol and syringol transformation by replacement of hydroxy and methoxy residues by chlorine atoms. Moreover, some chlorocatechols and chlorinated methoxyphenols were determined during catechol and methoxyphenols transformations. Higher concentrations of chlorinated compounds were observed in the alkaline environment during phenol transformation. Conversion of catechol and methoxyphenols generated higher amounts of chlorinated intermediates in the acidic medium. In samples carboxylic acids like acetic and formic acids were determined. The formation of these compounds was the result of the cleavage of aromatic structure of phenols.

Catechols↗
PubMed1977

Pesticide uptake into membranes measured by fluorescence quenching.

Pesticides that contain chlorine have been shown to quench the fluorescence of carbazole-labeled phospholipids. Incorporation of these carbazole-labeled phospholipds into model membranes provides a system that allows the rapid determination of the uptake rates of chlorinated hydrocarbons into model membranes. This technique can be used in the determination of diffusion rates and partition coefficients of chlorine-containing organic compounds in model membrane systems, and hence may provide a method by which the bioaccumulation potential of synthetic chlorine-containing compounds can be estimated.

Carbazoles↗
PubMed1977

[The determination of a small amount of chlorine in the atmosphere by using 4-nitroaniline (author's transl)].

The determination of small amount of chlorine in the atmosphere is carried on ordinarily by omicron-toluidine method at present. However, this method is not recommended because the issued colour is unstable and omicron-toluidine itself belongs in the first group member of the Ordinance on Prevention of Particular Chemical Hazards Substances. Authors recommend 4-nitroaniline method, reported by J. Gabbay etc., because this method is stable and more practical. Although the colour that issued from the reaction of chlorine with 4-nitroaniline is affected by the co-existence of reducing gas, e.g. SO2, H2S or organic gas, but this effect may be removed the co-existence of reducing gas, e.g. SO2, H2S or organic gas, but this effect may be removed by introducing the sample gas into the layer of H2SO4-52Cr2O7 mixture immersed in glassfiber filter for micro-analysis. In this paper, influence of pH of the issued colour, stability, stream velocity of samplegas and effect of reducing substance are discussed.

Air↗
PubMed1990

Genotoxicity of drinking waters.

Drinking waters in many countries have been shown to contain non-volatile polar mutagenic compounds as well as trihalomethanes. Their nature is uncertain, but one compound, a chlorinated furanone (3-chloro-4-(dichloro-methyl)-5-hydroxy-2(5H)-furanone;MX) seems to be responsible for one third to over one half of the mutagenicity. Its concentration seems to correlate rather well also with the total bacterial mutagenicity. Animal toxicity studies are being used to evaluate the possible carcinogenicity risk of this compound as a first stage in complete risk assessment of the whole complex mixture. Epidemiological risk assessment is also possible, since mutagenicity values can be predicted on the basis of organic material in the raw water and the amount of chlorine used. This information has been collected in Finland retrospectively from waterworks, and will be correlated with the Finnish Cancer Registry data.

Animals↗
PubMed2000

[Study on the molecular mechanism of genetic damages in body cells in mice treated with organic mutants in drinking water].

The genetic toxicity of some volatile compounds of chlorinated by-products have been determined in animal studies. But little is known at present about the genetic toxicity of nonvolatile matter in drinking water in vivo assay. In a sub-acute experiment, the mice were exposed to the organic compounds extracted from in-home tap water. The pathologic changes in the liver and kidney tissues were observed under microscope and electron microscope. The frequencies of micronuclei in polychromatic erythrocytes in mice chest bone marrow in the three treated groups were tested. The point mutants in p53 gene of liver, kidney and colon tissues in the high dosage group were examined by PCR-SSCP. Especially, the frequencies of mutations in exon 7 of p53 gene in those mice were higher than those in exon 5 of p53 gene. It showed that the study on the molecular genetic toxicity of organic mutants in vivo assay was possible.

Animals↗
PubMed1988

The bioavailability of sediment-sorbed chlorobenzenes to larvae of the midge, Chironomus decorus.

Larval stages of the midge, Chironomus decorus, were used to define the bioaccumulation of sediment-sorbed mono-, di-, tri-, and hexachlorobenzene. Larvae were exposed to high- and low-organic-content sediments that had been equilibrated with individual radiolabeled chlorobenzenes prior to testing. Equilibrium or nonequilibrium aqueous concentrations of the volatile test chemicals were flowed through sealed chambers in a sediment-water exposure system. The uptake of chlorobenzenes by midge larvae was rapid for all compounds tested, and apparent steady-state conditions were reached within 48 hr of exposure. Bioconcentration factors for the accumulation of chlorobenzenes from sediments and from interstitial and overlying waters were related to the octanol/water partition coefficients of the compounds. Because the diffusion of chlorobenzenes to overlying water during nonequilibrium flow through conditions was very slow, bioaccumulation was dependent on the concentration of the chemicals in interstitial water. These results show how benthic organisms may be able to accumulate significant levels of chlorinated aromatic compounds from ecosystems where their concentrations in the water column are relatively low.

Animals↗
PubMed1976

Synthesis and stereochemistry of 6-deoxy-6-halogeno-D-glucofuranose cyclic phosphates.

1, 2-O-Cyclohexylidene- and 1, 2-O-isopropylidene-alpha-D-glucofuranose react with hexa-alkylphosphorous triamides to give the corresponding 3, 5, 6-phosphites. Treatment of the latter compounds with chlorine and bromine affords 1, 2-substituted 6-deoxy-6-halogeno-alpha-D-glucofuranose 3, 5-phosphorohalogenidates. Replacement of halogen at phsophorus by hydroxyl and amino groups has been investigated. Cyclic phosphorohalogenidates isomerize in N, N-dimethylformamide. The stereochemistry of the compounds investigated was established by using 1H- and 13C-n.m.r. data.

Glucose↗
PubMed2002

Effects of selected metal oxides on the dechlorination and destruction of PCDD and PCDF.

OCDD and OCDF spiked silica/graphite based model fly ash containing various copper compounds and metal oxides were thermally treated under oxygen deficient conditions. All copper compounds tested showed a considerable dechlorination/hydrogenation reaction at 260 degrees C. After 30 min at 340 degrees C, less than 1% of the spiked OCDD and OCDF was recovered as T4CDD/F to OCDD/F. Other compounds tested demonstrated a lower rate of dechlorination compared to the copper compounds. However, all other metal oxides showed a small dechlorination effect at 260 degrees C, which was considerably increased at 340 degrees C. The model fly.ash containing the different copper compounds or metal oxides showed comparable PCDD and PCDF isomer patterns after thermal treatment. However, small differences were observed among the different tested compounds. The PCDD and PCDF isomer patterns on the model fly ashes were similar to patterns found during dechlorination experiments on fly ashes from waste incineration processes. Model fly ash containing Ca(OH)2 exhibited the highest destruction potential, but a low dechlorination potential. In contrast, model fly ash containing any of the remaining compounds tested, was found to predominantly dechlorinate the spiked OCDD and OCDF.

Benzofurans↗
PubMed2004

The effect of bisphenol A and chlorinated derivatives of bisphenol A on the level of serum vitellogenin in Japanese medaka (Oryzias latipes).

2,2-bis (4-hydroxyphenyl) propane or Bisphenol A (BPA), has been reported to behave as an endocrine disrupter below acute toxic levels, and is widely present in the water environment. Although BPA is easily chlorinated, very little is reported on the effect of chlorinated BPA to the aquatic organisms. In this study, the estrogenic activities of BPA and its chlorinated derivatives were evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka. In addition, the effect of sodium hypochlorite on the decomposition of BPA was tested. The relative potencies of estrogenic activities of chlorinated BPA descended in the order 3,3'-diCIBPA>BPA> or =3-CIBPA>3,3',5-triCIBPA, and no estrogenic activity was observed in 3,3',5,5'-tetraCIBPA. Lowest Observed Effect Concentration (LOEC) and No Observed Effect Concentration (NOEC) for both 3-CIBPA and 3,3'-diCIBPA were 500 microg/L and 200 microg/L, respectively. LOEC for 3,3',5-triCIBPA was >500 microg/L. When BPA was reacted with sodium hypochlorite (24 hours; residual chlorine at 1 ppm), however, complete decomposition of BPA and its chlorinated derivatives was observed. The decrease in BPA and its chlorinated derivatives paralleled the decrease in estrogenic potency evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka.

Animals↗
PubMed2003

'Super bugs' for bioremediation.

Chlorinated organic compounds are among the most significant pollutants in the world. Sequential use of anaerobic halorespiring bacteria, which are the key players in biological dehalogenation processes, and aerobic bacteria whose oxygenases are modified by directed evolution could lead to efficient and total degradation of highly chlorinated organic pollutants. Recently three interesting papers on halorespiration and polychlorinated biphenyl biodegradation were published.

Bacteria, Anaerobic↗
PubMed1995

Photoinstability of some tyrphostin drugs: chemical consequences of crystallinity.

PURPOSE: The purpose of this work was to study the photostability of the antiproliferative tyrphostin drug compounds RG 13022(I) and RG 14620(II) as a part of preformulation program. METHODS: The compounds were exposed to cool white fluorescent light in solution as well as in the solid state and analyzed by HPLC. The degradation products were isolated chromatographically and their structures determined by spectroscopic methods. X-ray crystallographic analyses of the above compounds and their solid state degradation products were carried out to understand the mechanism of photodegradation. RESULTS: The compounds were found to undergo efficient photochemical transformations in solution as well as in the solid state. The degradation in the solution was due to the photoisomerization into their E-isomers (III and IV). The solid state photodegradation products were [2 + 2]-cycloaddition products (V and VI). The stereochemistry of the photocycloaddition products was indicative of the crystal packing of their monomeric precursors. The photocycloaddition product of RG 13022 possesses the head-to-tail linkage as expected from the head-to-tail packing of RG 13022 molecules in the crystal. The photocycloaddition product of RG 14620, however, was found to involve head-to-head linkage in agreement with the head-to-head crystal packing of RG 14620. CONCLUSIONS: Drug compounds containing open chain olefinic double bonds could be sensitive to mild condition of light in the solid state if the distance between the two double bonds in the crystal approaches 4.2 degrees A and they have suitable UV absorption characteristics. Attractive interactions between chlorine atoms have significant influence in controlling the crystal packing of chlorinated aromatic compounds.

Alkenes↗
PubMed2002

New approach to immunochemical determinations for triclopyr and 3,5,6-trichloro-2-pyridinol by using a bifunctional hapten, and evaluation of polyclonal antiserum.

The present work describes the design and synthesis of the structurally unique hapten, "bifunctional hapten", to produce a group-specific polyclonal antiserum to triclopyr and 3,5,6-trichloro-2-pyridinol. A bifunctional hapten was designed and synthesized by conjugating commercially available Nepsilon-2,4-dinitrophenyl (DNP)-L-lysine to triclopyr, and then coupling this to carrier proteins such as bovine serum albumin (BSA). The synthesized bifunctional hapten greatly raised the antiserum titer in comparison with that of the conventional hapten, triclopyr. Antiserum with a sufficiently high titer to provide the determinations of targeted compounds was obtained only 63 days after the primary immunization. The obtained antiserum showed the highest affinity to triclopyr (IC(50) = 3.5 nM) and 3,5,6-trichloro-2-pyridinol (IC(50) = 5.1 nM) in homologous ELISA. The cross-reactivities to various agrochemicals and some chlorinated phenolic compounds were determined. Significant cross-reactivity was found to the herbicide 2,4,5-T. The antiserum reacted to both triclopyr and its metabolite. Assay sensitivity was evaluated for effects of various assay conditions, including pH value and concentrations of organic solvents and detergents. Under optimized assay conditions, the quantitative working range of triclopyr ELISA was from 0.1 to 5.2 ng/mL with a limit of detection (LOD) of 0.037 ng/mL, and an IC(50) of 0.72 ng/mL. On the other hand, the quantitative working range of 3,5,6-trichloro-2-pyridinol ELISA was from 0.13 to 6.0 ng/mL with a LOD of 0.052 ng/mL, and an IC(50) of 0.95 ng/mL. Water samples fortified with triclopyr or its metabolite at 1, 5, and 10 ng/mL were directly analyzed without extraction and cleanup by the proposed ELISA. The mean recovery was 101.6%, and the mean coefficient of variation (CV) was 7.1% in the case of the triclopyr ELISA. In the case of the 3,5,6-trichloro-2-pyridinol ELISA, the mean recovery was 99.8%, and the mean CV was 9.5%. The proposed ELISA turned out to be a powerful tool for monitoring of residual triclopyr or 3,5,6-trichloro-2-pyridinol in water samples at trace level.

2,4-Dinitrophenol↗
PubMed2004

Dehalococcoides ethenogenes strain 195 reductively dechlorinates diverse chlorinated aromatic pollutants.

Dehalococcoides ethenogenes strain 195 dechlorinates tetrachloroethene to vinyl chloride and ethene, and its genome has been found to contain up to 17 putative dehalogenase gene homologues, suggesting diverse dehalogenation ability. We amended pure or mixed cultures containing D. ethenogenes strain 195 with 1,2,3,4-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3-dichlorodibenzo-p-dioxin, 1,2,3,4-tetrachlorodibenzofuran, 2,3,4,5,6-pentachlorobiphenyl, 1,2,3,4-tetrachloronaphthalene, various chlorobenzenes, or a mixture of 2-, 3-, and 4-chlorophenol to determine the dehalogenation ability. D. ethenogenes strain 195 dechlorinated 1,2,3,4-tetrachlorodibenzo-p-dioxin to a mixture of 1,2,4-trichlorodibenzo-p-dioxin and 1,3-dichlorodibenzo-p-dioxin. 2,3,4,5,6- Pentachlorobiphenyl was dechlorinated to 2,3,4,6- and/or 2,3,5,6-tetrachlorobiphenyl and 2,4,6-trichlorobiphenyl. 1,2,3,4-Tetrachloronaphthalene was dechlorinated primarily to an unidentified dichloronaphthalene congener. The predominant end products from hexachlorobenzene dechlorination were 1,2,3,5-tetrachlorobenzene and 1,3,5-trichlorobenzene. We did not detect dechlorination daughter products from monochlorophenols, 2,3-dichlorodibenzo-p-dioxin or 2,3,7,8- tetrachlorodibenzo-p-dioxin. D. ethenogenes strain 195 has the ability to dechlorinate many different types of chlorinated aromatic compounds, in addition to its known chloroethene respiratory electron acceptors. Remediation of sediments contaminated with aromatic halogenated organic pollutants such as polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins could require billions of dollars in the coming years. Harnessing microorganisms such as Dehalococcoides spp. that detoxify these compounds via removal of halogens may lead to cost-effective biotechnological approaches for remediation.

Biodegradation, Environmental↗
PubMed2005

A concentration-dependent multi-term linear free energy relationship for sorption of organic compounds to soils based on the hexadecane dilute-solution reference state.

A LFER of the type in the title is applied to sorption of numerous compounds to polyethylene and three soils for which sorption to natural organic matter (NOM) is presumed dominant. It provides fractional contributions to the Gibbs free energy of sorption corresponding to hydrophobic effects, dipolar/polarizability (D/P) effects in excess of the reference state, and the sum of possible specific forces such as H-bonding and pi-pi electron donor-acceptor (pi-pi EDA) interactions in excess of the reference state. Minimal inputs are the isotherm, the n-hexadecane-water partition coefficient and the Abraham pi parameter representing D/P effects. Sorption of all compounds to polyethylene can be described by considering only hydrophobic effects. Sorption of a calibration set of apolar compounds (aromatic and aliphatic hydrocarbons and chlorinated hydrocarbons) to the natural sorbents is well-described by a combination of hydrophobic and D/P effects. For the apolar set, D/P contributes approximately 15-40% (2-8% for cyclohexane) of sorption free energy. D/P effects increase with the degree of chlorination for aliphatic compounds. For aromatic compounds D/P effects increase with fused ring size but do not vary with degree of chlorination and chlorine substitution pattern. H-bonding contributes substantially to sorption of alcohols, and similarly for 2-nonanol and 2,4-dichlorophenol (33-44%). pi-pi EDA forces contribute to phenanthrene sorption in one case. The effects of concentration, sorbent aromaticity (literature NMR), and sorbent polarity [(O + N)/C] on hydrophobic and D/P contributions for all compounds indicate that (a) molecules fill sites of progressively greater hydrophilic character; (b) the energy penalty for cavity formation in the solid decreases with concentration due to plasticization and greater intermolecular contact; (c) sorbent aromatic content more than sorbent polarity controls D/P interactions. Basing free energy on an inert electrostatic chemical environment afforded by n-hexadecane permits evaluation of direct electrostatic forces in NOM that contribute to sorption.

Adsorption↗
PubMed2004

Electrochemical inactivation of triclosan with boron doped diamond film electrodes.

This research investigated an electrochemical method for inactivating contaminated stockpiles of the biocidal agent, triclosan. The goal of the electrolysis was to produce products that were amenable to treatment in conventional activated sludge treatment systems. Triclosan oxidation in electrochemical cells with boron doped diamond (BDD) film anodes was investigated in aqueous solutions at a pH value of 12. Chronoamperometry experiments showed that direct oxidation of triclosan occurred at potentials below those for H2O, Cl-, or OH- oxidation. Measurable rates of triclosan oxidation began at potentials above 0.4 V with respect to the standard hydrogen electrode (SHE), while potentials of 0.5, 1.3, and 1.8 V were required to obtain measurable oxidation rates of H2O, Cl-, and OH-, respectively. At anode potentials below 2 V, the dominant electrode reaction involved direct triclosan oxidation, while indirect oxidation was the dominant pathway at higher potentials. However, cyclic voltammetry experiments showed that direct oxidation of triclosan resulted in the formation of a passivating film on the electrode that could only be removed by oxidation at potentials above 3 V. Direct triclosan oxidation showed a very weak potential dependence, suggesting that its oxidation was limited by chemical dependent factors rather than by an outer-sphere electron transfer reaction. Organic triclosan oxidation products consisted primarily of chlorinated acetic acids and chlorinated phenolic compounds. Although the byproducts of triclosan oxidation became increasingly less reactive with increasing electrolysis time, triclosan could be completely oxidized to CO2 at current densities above 2 mA/cm2. Microtox testing indicated that residual triclosan accounted for nearly all the toxicity in the treated water, despite the fact that chlorinated byproduct concentrations were significantly higher than those of triclosan itself.

Anti-Infective Agents, Local↗
PubMed1984

Pharmacodynamics of alcide, a new antimicrobial compound, in rat and rabbit.

Alcide is a germicidal preparation which has been shown to kill a wide range of common pathogenic bacteria as well as fungi, in vitro. This preparation is composed of Part A and Part B which contains sodium chlorite (NaClO2) and lactic acid as the active ingredients, respectively. The two parts are combined in equal volumes immediately prior to application resulting in the formation of chlorine dioxide (ClO2). Alcide gel was applied to the shaven backs of 18 female Sprague-Dawley rats in a 2.0-g/kg dose by combining 1 g of each part immediately prior to administration. This dose was applied for a period of 10 days to reach a steady state. On the 11th day, 36Cl-labeled Alcide gel, which contained Na36ClO2 in Part A, was administered to the animals in a 0.6-g dose (2.0 g/kg) containing 0.1 microCi. The half-life for 36Cl absorption was 22.1 hr while the elimination half-life was 64.0 hr. 36Cl was excreted by the kidneys with chloride (Cl-) and chlorite as the metabolites. Ninety-six hours after Alcide administration, radioactivity was highest in whole blood and lowest in fat. In a 90-day subchronic dermal toxicity study in rabbits, exposure to Alcide gel resulted in decreased glutathione concentrations in blood of the group receiving 2.0 g/kg Alcide as well as in the placebo gel group which received the same dose of gel.

Animals↗