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PubMed2001

The potential of anaerobic bacteria to degrade chlorinated compounds.

Chlorinated ethenes and chlorinated aromatics are often found as pollutants in sediments, groundwater, and wastewater. These compounds were long considered to be recalcitrant under anaerobic conditions. In the past years however, dechlorination of these compounds has been found to occur under anaerobic conditions at contaminated sites and in wastewater treatment systems. This dechlorination is mainly attributed to halo-respiring bacteria, which are able to couple this dechlorination to energy conservation via electron transport coupled phosphorylation. The dechlorinating activities of the halo-respiring bacteria seem to be confined to the dechlorination of chloroethenes and chlorinated aromatic compounds. In addition, methanogenic and acetogenic bacteria are also able to reduce the chlorinated ethenes via a-specific cometabolic pathways. Although these latter reactions may not be important in the remediation of contaminated sites, they may be of substantial influence in the start-up of remediation processes and in the application of granular sludge from UASB reactors. Specific halo-respiring bacteria may be used to increase the dechlorination activities via bioaugmentation in the case that the appropriate microorganisms are not present at the contaminated site or in the sludge.

Bacteria, Anaerobic↗
PubMed1991

Cancer incidence among pulp and paper workers exposed to organic chlorinated compounds formed during chlorine pulp bleaching.

The risk of cancer of 152 male workers exposed to organic chlorine compounds formed during chlorine pulp bleaching was assessed in a retrospective cohort study. The men had worked continuously for at least one year in selected job categories between 1 January 1945 and 31 December 1961. The cohort was followed for death and cancer incidence until 31 December 1987 with the use of the data of the National Population Register and the Finnish Cancer Registry. There were 12 observed cancers against 8.1 expected [standardized incidence ratio (SIR) 1.5, 95% confidence interval (95% CI) 0.8-2.6]. Among the stock preparation workers (N = 53), a significantly elevated risk of lung cancer was found (6 observed, 1.0 expected, SIR 6.3, 95% CI 2.3-14) that was especially prominent after a latency (time since first employment) of at least 15 years and in the age group of 35 to 59 years. Although all of the cases involved smokers, a part of the increased incidence may be associated with the workplace exposure to organic chlorinated compounds.

Adult↗
PubMed2005

Chlorine covers on living bacteria: the initial step in antimicrobial action of active chlorine compounds.

OBJECTIVES: Although active chlorine compounds are well-known antimicrobial agents in human medicine, their initial steps of action have not been completely clarified. Using N-chlorotaurine (NCT), an endogenous mild representative, we observed persisting oxidation capacity affixed to bacteria. It was the aim of this study to investigate this 'chlorine cover'. METHODS: Pathogens were incubated in NCT, which was subsequently washed off. The oxidation capacity on the bacterial surface was measured photometrically. RESULTS: Superficial chlorination in the form of covalent N-Cl bonds to Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans could be attached before killing took place. For S. aureus, 3 min incubation with NCT produced a cover of 3.3 x 10(-16) mol Cl(+)/cfu, while the cfu count was reduced by only 26%. The kind of microorganism, coating time, pH, buffer system and, basically, the chlorine compound, influenced the cover strength. The relative cover strength on S. aureus by NCT, chloramine T, sodium dichloro-isocyanurate or N,N-dichlorotaurine was 1:15.7:38.7:0.24. Chlorine covers were surprisingly stable and could be detected for 3 h at 20 degrees C (>8 h at 1 degrees C), even without a reduction of cfu. However, addition of 5% ammonium chloride caused a rapid loss of viability, explained by formation of highly bactericidal NH(2)Cl, an effect that resembles the ignition of a time-bomb. CONCLUSIONS: The chlorine cover can be regarded as the first sign of interaction between chlorinating agent and microorganism, and may explain the non-lethal features of postantibiotic effect and attenuation of bacterial virulence. Furthermore, it may be a decisive step in bacterial inactivation by the myeloperoxidase-hypochlorite system in innate immunity.

Bacteria↗
PubMed1986

Identification of chlorinated compounds in the spent chlorination liquor from differently treated sulphite pulps with special emphasis on mutagenic compounds.

About 80 compounds present in the spent chlorination liquor from the bleaching of sulphite pulp have been identified. A comparison has been made between these compounds and those identified in kraft bleaching effluent, with special emphasis on mutagens. The influence of oxygen delignification, before chlorination and alkali treatment of the spent bleach liquor, on the composition of the liquors has also been investigated.

Aldehydes↗
PubMedDate not supplied

Chlorinated compounds and phenols in tissue, fat, and blood from rats fed industrial waste site soil extract: methods and analysis.

A method was developed to analyze rat tissue, fat, and blood for some of the chlorinated compounds found in an extract of soil from an industrial waste site. Extraction with hexane and then with ethyl ether-hexane (1 + 1) was followed by concentration over steam, and gas chromatographic analysis with an electron capture detector. Volatile compounds were analyzed in a glass column coated with 6% SP-2100 plus 4% OV-11 on Chromosorb W. Semivolatile compounds, chlorinated compounds, and pesticides were analyzed in a 70 m glass capillary column coated with 5% OV-101. Phenols were analyzed in a glass column packed with 1% SP-1240 DA on Supelcoport. However, the most efficient means of separation was to use the same glass column for volatile compounds, a DB-5 fused silica capillary column for semivolatile compounds, pesticides, and phenols, and the same 1% SP-1240 DA glass column for separation of beta-BHC and pentachlorophenol. Recoveries ranged from 86.3 +/- 9.1% (mean +/- standard deviation) to 105 +/- 10.4%. Sensitivities for semivolatile chlorinated compounds, pesticides, and phenols were about 4 ng/g for fat, 1 ng/g for tissue, and 0.2 ng/mL for blood. Sensitivities for volatile compounds were about 4-fold higher (16, 4, and 0.8, respectively). Sensitivities for dichlorobenzenes and dichlorotoluenes were 8 ng/g for fat, 2 ng/g for tissue, and 0.4 ng/mL for blood.

Adipose Tissue↗
PubMed2000

Characterization of chlorinated compounds using a dual chlorine-selective pulsed discharge emission detector-helium-pulsed discharge photoionization detector system.

The Cl-selective pulsed discharge emission detector (Cl-PDED) response is dependent only upon the Cl content, irrespective of the molecular structures of the compounds. This provides a simple, fast quantitative method of analysis for chlorinated compounds. The response of the helium-pulsed discharge photoionization detector (He-PDPID) is a function of the molecular structure and the number of photoionizable electrons using the He2 band at 13.5-17.5 eV. The ratio of the responses of the two detectors is independent of concentration and can be used to characterize the Cl-containing compounds along with the retention time, or the ratio can be used as evidence for coelution. The dual Cl-PDED-He-PDPID detector system is a useful tool for peak identification. The effect of coeluting hydrocarbons on the Cl-PDED response was evaluated by spiking a gasoline sample with US Environmental Protection Agency mixture 502. All Cl-PDED responses were greater than 90% of the response in the absence of the hydrocarbons.

Chlorine↗
PubMed2003

Microbial genes and enzymes in the degradation of chlorinated compounds.

Microorganisms are well known for degrading numerous natural compounds. The synthesis of a multitude of chlorinated compounds by the chemical industry and their release into the natural environment have created major pollution problems. Part of the cause of such pollution is the inability of natural microorganisms to efficiently degrade synthetic chlorinated compounds. Microorganisms are, however, highly adaptable to changes in the environment and have consequently evolved the genes that specify the degradation of chlorinated compounds to varying degrees. Highly selective laboratory techniques have also enabled the isolation of microbial strains capable of utilizing normally recalcitrant highly chlorinated compounds as their sole source of carbon and energy. The evolution and role of microbial genes and enzymes, as well as their mode of regulation and genetic interrelationships, have therefore been the subjects of intense study. This review emphasizes the genetic organization and the regulation of gene expression, as well as evolutionary considerations, regarding the microbial degradation of chlorobenzoates, chlorocatechols, and chlorophenoxyacetic acids.

Bacteria↗
PubMed1996

Bacterial glutathione: a sacrificial defense against chlorine compounds.

Aerobic organisms possess a number of often overlapping and well-characterized defenses against common oxidants such as superoxide and hydrogen peroxide. However, much less is known of mechanisms of defense against halogens such as chlorine compounds. Although chlorine-based oxidants may oxidize a number of cellular components, sulfhydrl groups are particularly reactive. We have, therefore, assessed the importance of intracellular glutathione in protection of Escherichia coli cells against hydrogen peroxide, hypochlorous acid, and chloramines. Employing a glutathione-deficient E. coli strain (JTG10) and an otherwise isogenic glutathione-sufficient E. coli strain (AB1157), we find that glutathione-deficient organisms are approximately twice as sensitive to killing by both hydrogen peroxide and chlorine compounds. However, the mode of protection by glutathione in these two cases appears to differ: exogenous glutathione added to glutathione-deficient E. coli in amounts equal to those which would be present in a similar suspension of the wild-type bacteria fully restored resistance of glutathione-deficient bacteria to chlorine-based oxidants but did not change resistance to hydrogen peroxide. Furthermore, in protection against chlorine compounds, oxidized glutathione is almost as effective as reduced glutathione, implying that the tripeptide and/or oxidized thiol undergo further reactions with chlorine compounds. Indeed, in vitro, 1 mol of reduced glutathione will react with approximately 3.5 to 4.0 mol of hypochlorous acid. We conclude that glutathione defends E. coli cells against attack by chlorine compounds and hydrogen peroxide but, in the case of the halogen compounds, does so nonenzymatically and sacrificially.

Chloramines↗
PubMed2002

Not only training but also exposure to chlorinated compounds generates a response to oxidative stimuli in swimmers.

Relations between exposure to chlorinated compounds and biological markers of response to oxidative stimuli were investigated in swimmers, taking into account the effect of training. Twenty-two male swimmers aged 15-25 years were surveyed twice. Prevalence of irritant symptoms and asthma and number of hours of training were reported. Exposure to nitrogen trichloride (NCl3) and blood response to oxidative stimuli [catalase, superoxide dismutase (Cu2+/Zn2+ SOD), glutathione peroxidase (GSH-Px) activities and ceruloplasmin, ferritin and total antioxidant concentrations] were measured. Univariate analyses were completed by multivariate analyses. High prevalences of irritant symptoms and asthma were found. Multivariate analysis confirmed the results of the univariate analyses and showed that Cu2+/Zn2+ SOD activity was increased by exposure and by training (P = 0.01, P = 0.0001, respectively). Erythrocyte GSH-Px was decreased, whereas plasma GSH-Px was increased by exposure (P = 0.002, P = 0.002). No other association was found. Higher irritant symptoms and increases in the activities of erythrocyte Cu2+/Zn2+ SOD and of plasma GSH-Px with exposure support the hypothesis that the production of reactive oxygen species is not only related to training but also to exposure to chlorinated compounds. Other athletes tend to have respiratory problems such as asthma, but the exposure to chlorinated compounds may increase the respiratory disease among swimmers.

Adolescent↗
PubMed1976

Evaluation of chlorine compounds for surface disinfection by laboratory and in-use testing.

The disinfecting properties of chloramine and compounds containing chlorinated trisodium phosphate and potassium bromide or sodium dichlorisocyanurate and detergents were studied by laboratory and in-use tests and compared with a phenolic disinfectant containing detergents. In a modified Kelsey test all the preparations were effective in the recommended dilutions in clean conditions. The effectiveness of the chlorine-bromine disinfectant substantially decreased in the presence of organic material. The in-use testing was performed in infectious disease and intensive care wards. Chloramine was so disliked that the in-use test could not be carried out. In the infectious disease ward the total bacterial colony counts of the floors (disinfected once a day) were twice as high as those of the intensive care ward (disinfected 3 times a day) during the use of the phenolic and chlorine-bromine disinfectants. The frequent cleaning routine seemed thus to have an effect on the microbial contamination of the floors. The same difference was found in the contamination of the other non-vertical surfaces although they were disinfected only once a day in both wards. In both wards the total bacterial colony counts of all non-vertical surfaces were lower during the use of halogen compounds than during the use of the phenolic disinfectant. The staff, however, complained of the irritation of the skin and the mucous membranes when using chlorine disinfectants.

Chloramines↗
PubMed2006

Assessment of organic chlorinated compound removal from aqueous matrices by adsorption on activated carbon.

Adsorption on activated carbon is currently the most frequently used technology to remove organic chlorinated pollutants from wastewaters. The present study examines the ability of five commercially available types of activated carbon to remove organic chlorinated compounds from the effluent of a chemical plant. The various types were tested on the basis of Freundlich adsorption isotherms for 14 pure organic chlorinated compounds, of molecular weight ranging from that of dichloromethane (MW=84.93 gmol(-1)) to hexachlorobenzene (MW=284.78 gmol(-1)). The best was selected and used in a laboratory fixed-bed column to assess its removal efficiency with respect to the tested organic chlorinated compounds. Removal efficiency was always higher than 90%. These results provide information necessary to optimize scale-up from the pilot plant to the real one.

Adsorption↗
PubMed1981

Enhancement of the microbial dehalogenation of a model chlorinated compound.

A number of chlorinated aromatic and aliphatic compounds were dehalogenated when incubated with sewage. Preincubating the sewage with nonchlorinated organic substrates enhanced the subsequent dehalogenation of the chlorinated chemicals. Dehalogenation of 4-chloro-3,5-dinitrobenzoic acid (CDBA) in lake water occurred as a result of microbial growth both in the light in the absence of added nutrients and in the dark in the presence of acetate. No organism able to use CDBA as a carbon source was isolated. Axenic bacterial cultures and a nonaxenic Chlamydomonas culture released chloride from CDBA. The metabolism of CDBA by the latter culture, a process that was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea, yielded a product that was identified as alpha-hydroxymuconic semialdehyde. This product of an apparent cometabolic transformation was mineralized by a strain of Streptomyces, thus suggesting that certain cometabolic products may not accumulate because they are carbon sources for other species.

Journal Article↗
PubMed2006

Levels of chlorinated compounds (CPs, PCPPs, PCDEs, PCDFs and PCDDs) in soils at contaminated sawmill sites in Sweden.

Soil samples from five contaminated sawmill sites in Sweden were characterized with respect to chlorophenols (CP), chlorinated phenoxy phenols (PCPP, hydroxylated chlorinated diphenyl ethers), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD). The composition of chlorinated compounds in the soil samples was compared to the composition of two preservatives commonly used in the Scandinavian wood impregnation industry: the 2,3,4,6-tetrachlorophenol preservative called Ky-5 and the pentachlorophenol preservative Dowicide G. The levels of CPs in the soil samples ranged from 0.1 to 4500 mgkg-1 d.w., PCPPs from <0.15 to 940 mgkg-1 d.w., PCDEs from <38 to 6800 microgkg-1 d.w., PCDFs from 7.4 to 18000 microgkg-1 d.w. and PCDDs from 9.9 to 35000 microgkg-1 d.w. The resulting WHO-TEQ of PCDD/Fs in the soil samples ranged from 0.14 to 3000 microgkg-1 d.w. Despite a wide range of concentrations the congener compositions were similar within tetrachlorophenate and pentachlorophenate contaminated soils respectively. The contamination at each sawmill site may be linked to the use of either a tetrachlorphenol preservative, e.g. Ky-5, or a pentachlorophenol preservative, e.g. Dowicide G. Best-fit calculations were used to compare the chlorinated phenol contents of the preservatives to those of the soil samples. This revealed a positive correlation between the hydrophobicity (logKow) of contaminants and the ratio of their levels in soil to preservatives. The relative abundance of the chlorinated compounds varied greatly between the five sites studied, suggesting that their transport parameters differ substantially.

Benzofurans↗
PubMed1995

Evaluation of the use of uncertainty factors in deriving RfDs for some chlorinated compounds.

Risk assessment of exposure to chemicals having a toxic endpoint routinely uses the reference dose (RfD) approach based on uncertainty factors of 10. The purpose of this investigation was to evaluate whether the magnitude of the U.S. Environmental Protection Agency (EPA) 10x uncertainty factors has scientific merit when compared with data from recent human and animal experimental studies. A compilation and comparison of ratios between LOAEL/NOAEL (lowest observed adverse effect level/no observed adverse effect level) and subchronic/chronic values was made for six chlorinated compounds, namely, carbon tetrachloride, methylene chloride, pentachlorophenol, monochlorobenzene, chlorpyrifos, and 1,1-dichloroethane. Data sets demonstrated that 91.3% of the LOAEL/NOAEL ratios were < or = 6 while 87% of the ratios for the same parameter were < or = 5. Furthermore, subchronic/chronic ratios were < or = 3.5. From our investigation we concluded that automatic safety factors of 10x are not scientifically supportable and are overly conservative for the chlorinated compounds studied here.

Animals↗
PubMed1993

Background soil concentrations of phenolic compounds, chlorinated herbicides, PCDDs and PCDFs in the Melbourne metropolitan area.

During June and July 1990, surface soil samples were taken in the Melbourne metropolitan area and analysed for phenolic compounds, chlorinated herbicides, polychlorinated dibenzo-para-dioxins (PCDDs) and polychlorinated furans (PCDFs). A surface soil sample from a Werribee Farm Treatment Complex paddock, where cattle graze on land that is used for filtration of sewage, was also taken and analysed. No phenolic compounds or chlorinated herbicides were detected at the parts per billion detection limits in any of the samples. PCDDs and PCDFs were detected in both industrial and nonindustrial sectors of the Melbourne metropolitan area, as well as in effluent from Nufarm Limited, an agricultural chemicals manufacturer in Laverton North, in similar concentrations (toxic equivalents in the parts per trillion range). These concentrations were consistent with background levels identified in other major urban areas. There was no evidence of the Nufarm effluent fingerprint in any of the background soil samples analysed. The fingerprint profile of the sample taken from Werribee Farm, although showing traces of the Nufarm effluent fingerprint, was clearly distinct from that effluent fingerprint and consistent with the fingerprint identified in the background soils. The impact of the Nufarm effluent on the area, therefore, was considered insignificant.

Benzofurans↗
PubMed2004

Different levels of polybrominated diphenyl ethers (PBDEs) and chlorinated compounds in breast milk from two U.K. Regions.

Polybrominated diphenyl ether (PBDE) congeners are constituents of flame retardants, and there is growing concern regarding their persistence, bioaccumulation, and toxicity. We collected breast milk samples between late 2001 and early 2003 from 54 U.K.-resident mothers. Of these, 27 originated from southeast England (London), and the other 27 originated from northwest England (Lancaster). Analysis of milk-fat extracts by gas chromatography-mass spectrometry was performed to determine the levels of 15 PBDE congeners, 15 polychlorinated biphenyl (PCB) congeners, and other selected chlorinated compounds. PCB and organochlorine (OC) levels in southeast samples were consistently higher, and significant differences (p < 0.05) were observed. Sigma PBDE levels ranged from 0.3 to 69 ng/g lipid (geometric mean, 6.6 ng/g), and PBDE-47 was the most abundant congener. Sigma PCB levels ranged from 26 to 530 ng/g lipid (geometric mean, 150 ng/g) and were composed mainly of PCB-153 (26%), PCB-138 (20%), and PCB-180 (13%). OC levels for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its metabolites (Sigma DDX) ranged from 24 to 2,300 ng/g lipid (geometric mean, 160 ng/g);Sigma hexachlorocyclohexane levels ranged from 1.2 to 1,500 ng/g lipid (geometric mean, 16 ng/g). Using nuclear magnetic resonance-based metabonomics, samples (n = 7) containing the highest contaminant levels were compared with samples (n = 7) containing the lowest levels. Excellent separation along the first principal component implied that the chemical constituents of the two groups were significantly different. Although reasons for such differences remain obscure, lifestyle factors associated with a more heterogeneous London cohort could be responsible. Identifying primary routes of contaminant exposures and their biologic effects is of great importance. Key words: breast milk, flame retardants, gas chromatography-mass spectrometry, milk-fat extracts, organochlorines, PBDE-47, persistent contaminants, polybrominated diphenyl ethers, polychlorinated biphenyls, United Kingdom.

Adult↗
PubMed1991

The effect of organic chlorine compounds and their metabolites present in human milk on newborn mice.

The effect of pesticides and their metabolites (DDE, DDT, DDD, alpha, beta and gamma-HCH and PCBs) isolated from human milk on the blood and liver morphology of the mouse were studied. Mouse neonates were fed an extract of the organochlorine compounds in linseed oil for a period of 6 weeks. The lowest dose used in the experiment equalled that which a human infant can receive with its mother's milk, calculated per gram of body weight. Doses 10 and 100 times higher were also used. At the end of the experiment, tissue samples for electron microscopy and blood samples for haemotological examination were taken. Haematological examinations, in mice receiving pesticides, revealed a significant rise in the number of Heinz bodies in erythrocytes and an increased number of lymphocytes. These changes were related to the concentrations of the organic chlorine compounds that the animals were given. Electronmicroscopy demonstrated that organochlorine pesticides at doses equal to that might be received by infants caused proliferation of the smooth endoplasmic reticulum in hepatocytes without any clear damage to other subcellular structures. Doses 10 and 100 times higher resulted in more extensive proliferation of the smooth endoplasmic reticulum, reduction of the rough elements of the endoplasmic reticulum and damage to mitochondria. The latest changes were associated with an increased number of prominent Kupffer cells and the appearance of immigratory cells with traits characteristic of lymphocytes and monocytes.

Administration, Oral↗