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PubMed1988

Degradation and O-methylation of chlorinated phenolic compounds by Rhodococcus and Mycobacterium strains.

Three polychlorophenol-degrading Rhodococcus and Mycobacterium strains were isolated independently from soil contaminated with chlorophenol wood preservative and from sludge of a wastewater treatment facility of a kraft pulp bleaching plant. Rhodococcus sp. strain CG-1 and Mycobacterium sp. strain CG-2, isolated from tetrachloroguaiacol enrichment, and Rhodococcus sp. strain CP-2, isolated from pentachlorophenol enrichment, mineralized pentachlorophenol and degraded several other polychlorinated phenols, guaiacols (2-methoxyphenols), and syringols (2,6-dimethoxyphenols) at micromolar concentrations and were sensitive to the toxic effects of pentachlorophenol. All three strains initiated degradation of the chlorophenols by para-hydroxylation, producing chlorinated para-hydroquinones, which were then further degraded. Parallel to degradation, strains CG-1, CG-2, and CP-2 also O-methylated nearly all chlorinated phenols, guaiacols, syringols, and hydroquinones. O-methylation of chlorophenols was a slow reaction compared with degradation. The preferred substrates of the O-methylating enzyme(s) were those with the hydroxyl group flanked by two chlorine substituents. O-methylation was constitutively expressed, whereas degradation of chlorinated phenolic compounds was inducible.

Anisoles↗
PubMedDate not supplied

[Pesticides in the diet: adding pieces to the puzzle].

OBJECTIVES: To improve information on exposure to pesticides through diet in Spain by reporting the results on 88 pesticide parameters in 1,109 food samples obtained between 1998 and 2003 as part of the Barcelona program for research on the health quality of foods. MATERIAL AND METHOD: The results are presented by food groups. For fruits and vegetables, the results were compared with those for the previous period. Statistical comparisons were performed using the chi2 test. RESULTS: Of the 1,109 samples, 116 were positive for pesticides (10.5%). Persistent chlorinated compounds were detected in 1.5% and other compounds were found in 14.4%. Positive results were concentrated in fruits, vegetables, spices, cereals and their derivatives. There were no positive results among vegetable oils, eggs or fish products, and almost none in dairy products and meats. Fruits contained the greatest number of pesticides but none were persistent. Vegetables contained fewer pesticides, but some of these were persistent chlorinated compounds. Comparison of the results for fruits and vegetables with those of the 1989-97 period revealed no significant trends. CONCLUSIONS: Although a considerable number of samples contained pesticides, most of these were not persistent chlorinated compounds. The number of pesticides in fruits was notable.

Food Contamination↗
PubMed2006

Persistence of pharmaceuticals and other organic compounds in chlorinated drinking water as a function of time.

Ninety eight pharmaceuticals and other organic compounds (POOCs) that were amended to samples of chlorinated drinking-water were extracted and analyzed 1, 3, 6, 8, and 10 days after amendment to determine whether the total chlorine residual reacted with the amended POOCs in drinking water in a time frame similar to the residence time of drinking water in a water distribution system. Results indicated that if all 98 were present in the finished drinking water from a drinking-water treatment plant using free chlorine at 1.2 mg/L as the distribution system disinfectant residual, 52 POOCs would be present in the drinking water after 10 days at approximately the same concentration as in the newly finished drinking water. Concentrations of 16 POOCs would be reduced by 32% to 92%, and 22 POOCs would react completely with residual chlorine within 24 h. Thus, the presence of free chlorine residual is an effective means for transforming some POOCs during distribution.

Chlorine↗
PubMed2001

A biological loss of endosulfan and related chlorinated organic compounds from aqueous systems in the presence and absence of oxygen.

Endosulfan is a cyclodiene organochlorine currently widely used as an insecticide throughout the world. This study reports that the endosulfan isomers can be readily dissipated from aqueous systems at neutral pH in the absence of biological material or chemical catalysts, in the presence or absence of oxygen. The study showed that aldrin, dieldrin, and endosulfan exhibit bi-phasic loss from water in unsealed and butyl rubber sealed vessels. Half-lives are substantially increased for endosulfan I when oxygen is removed from the incubation vessel. The study conditions, where PTFE was used, were such that loss due to volatilization and alkaline chemical hydrolysis was eliminated. Half-lives determined from these data indicate that the parent isomers are much less persistent than the related cyclodienes, aldrin and dieldrin, confirming the findings of previous studies. The major oxidation product of endosulfans I and II, endosulfan sulfate, is less volatile and can persist longer than either of the parent isomers. Endosulfan sulfate was not formed in any of the treatments suggesting that it would not be formed in aerated waters in the absence of microbial activity or strong chemical oxidants. Since endosulfan sulfate is formed in many environments through biological oxidation, and is only slowly degraded (both chemically in sterile media and biologically), it represents a predominant residue of technical grade endosulfan, which finds its way into aerobic and anaerobic aquatic environments. The data obtained contributes to and confirms the existing body of half-life data on endosulfan I and II and its major oxidation product, endosulfan sulfate. The half-life data generated from the current study can be used in models for predicting the loss of chlorinated cyclodiene compounds from aqueous systems. The findings also highlight the importance of critically reviewing half-life data, to determine what the predominant processes are that are acting on the compounds under study.

Aerobiosis↗
PubMed2007

Metal catalyzed formation of chlorinated aromatic compounds: a study of the correlation pattern in incinerator fly ash.

Chlorinated aromatics are unintentionally formed and released from combustion and other thermal processes involving organic matter and chlorine. The catalytic activity of incinerator fly ash in the low-temperature formation of chlorinated aromatics has been demonstrated in both laboratory experiments and full-scale trials. Copper has been shown to be an effective catalyst, but several other transition metals possess a similar activity. Here results are reported from a series of full-scale combustion trials with different fractions of household and industrial wastes, with waste from forestry as a reference fuel. The composition of elements and chlorinated aromatics in the fly ash was evaluated with principal component analysis and partial least squares regression. The observed correlation pattern indicates that metals other than copper are of equal importance for the catalytic activity. Chromium and nickel are two of these metals, which may contribute to the de novo formation of chlorinated benzenes, phenols, PCDD and PCDF.

Air Pollutants↗
PubMed1986

Complete reductive dechlorination and mineralization of pentachlorophenol by anaerobic microorganisms.

Anaerobically digested municipal sewage sludge which had been acclimated to monochlorophenol degradation for more than 2 years was shown to degrade pentachlorophenol (PCP). Di-, tri-, and tetrachlorophenols accumulated when PCP was added to the individual acclimated sludges. When the 2-chlorophenol- (2-CP), 3-CP-, and 4-CP-acclimated sludges were mixed in equal volumes, PCP was completely dechlorinated. The same results were obtained in sludge acclimated to the three monochlorophenol isomers simultaneously. With repeated PCP additions, 3,4,5,-trichlorophenol, 3,5-dichlorophenol, and 3-CP accumulated in less than stoichiometric amounts. All chlorinated compounds disappeared after PCP additions were stopped. All chlorinated compounds disappeared after PCP additions were stopped. Incubations with [14C]PCP resulted in 66% of the added 14C being mineralized to 14CO2 and 14CH4. Technical-grade PCP was found to be degraded initially at a rate very similar to that of reagent-grade PCP, but after repeated additions, the technical PCP was degraded more slowly. Pentabromophenol was also rapidly degraded by the mixture of acclimated sludges. These results clearly show the complete reductive dechlorination of PCP by the combined activities of three chlorophenol-degrading populations.

Bacteria, Anaerobic↗
PubMed2006

Change of estrogenic activity and release of chloride ion in chlorinated bisphenol a after exposure to ultraviolet B.

Bisphenol A (BPA) and chlorinated bisphenol A (ClBPAs) were detected in wastewater from waste paper recycling plants. In previous study, we showed the acute cytotoxicity of oxidized products of BPA and ClBPAs generated by ultraviolet (UV) irradiation. However, estrogenic activities of these photoproducts have not been studied. Therefore, we investigated change of estrogenic activities of BPA and ClBPAs [3-chlorobisphenol A (3-ClBPA), 3,3'-dichlorobisphenol A (3,3'-diClBPA) and 3,3',5-trichlorobisphenol A (3,3',5-triClBPA)] after UVB irradiation using yeast two-hybrid assay. The agonist activities of ClBPAs were higher than that of BPA in the absence of S9. ClBPAs irradiated with UVB lost agonist activities. The addition of S9 also completely erased the activity. The antagonist activities of BPA and ClBPAs with or without UVB irradiation were not detected both in the absence or presence of S9. UVB irradiation (0-100 J/cm2) decreased the agonist activity of 3,3'-diClBPA in proportion to increase of released chloride ion. The agonist activity was completely lost at 50 J/cm2 of UVB, of which dose could dissociated almost all chlorine. These findings suggested that UVB irradiation could decrease the estrogenic activity of chlorinated compounds, which was due to the selective release of chloride ion.

Benzhydryl Compounds↗
PubMed2003

[Determination and QSPR study on the electrochemical reduction characteristics of chlorinated aromatic compounds].

The relationship between the reduction characteristics and molecular structure of 87 chlorinated aromatics including naphthalenes, biphenyls, benzenes and phenols was studied by using quantitative structure-property relationship technique. The result indicated that there was significant correlation between reduction potential and the energy of the lowest unoccupied molecular orbital and the number of chlorine atoms in molecule. The study threw more light on the nature of reduction process, and provided valuable basic data for designing and optimizing treatment process.

Benzene↗
PubMed1982

Toxicological effects of chlorine dioxide, chlorite and chlorate.

Review of the available literature obtained from both acute and chronic experiments utilizing rats, mice and chickens treated with ClO2, ClO2- and ClO3-in drinking water has demonstrated alterations in hematologic parameters in all species tested. The effects were usually dose related and marked changes occurred only at the higher dosages (up to 1000 mg/l.). In chronic studies, rats have been given ClO2 at doses of up to 1000 mg/l., and NaClO2 or NaClO3 at up to 100 mg/l., in their drinking water for one year. Treatment groups receiving ClO2, ClO2- or ClO3- showed alterations in erythrocyte morphology and osmotic fragility; at higher dosages mild hemolytic anemia occurred. An examination of blood glutathione content and RBC enzymes involving glutathione formation showed a dose-related diminution of glutathione in chlorine compound treated groups. The higher oxidative capacity of the chlorine compounds resulting in the decreased erythrocytic glutathione might well be the principal biochemical event leading to the other hematological alterations. More recent data show that ClO2, ClO2- and ClO3- alter the incorporation of 3H-thymidine into the nuclei of various organs of the rat. These data suggest the possibility of increased turnover cells of the gastrointestinal mucosa and inhibited DNA synthesis in several organs. In the latter category, most concern revolves around whether or not the apparent depression of DNA synthesis in the testes is associated with depressed spermatogenesis and reproductive toxicity in the male rat.

Animals↗
PubMed1997

Effectiveness of sanitation with quaternary ammonium compound or chlorine on stainless steel and other domestic food-preparation surfaces.

The relative ability of various materials used for domestic and/or food-service sinks and countertops to be sanitized was determined. Both smooth (unused) and abraded surfaces were tested by exposure to 200 mg of quaternary ammonium compound per liter or 200 mg of sodium hypochlorite per liter. Surface materials tested included mechanically polished (type 304, #4 finish) and electropolished stainless steel, polycarbonate, and mineral resin. Surfaces were prepared for testing by allowing attachment of a Staphylococcus aureus culture for 4 h to achieve an initial attached population of 10(4) to 10(5) CFU/cm2. The test procedure involved immersion of the surface in sanitizer solution followed by wiping with a sanitizer-saturated cloth. Residual staphylococci were detected by overlaying agar directly on the treated surface. Results indicated that the stainless steels and the smooth polycarbonate, which had 0.5 log CFU/cm2 or fewer of residual staphylococci, were more readily sanitized by quaternary ammonium compound than were either the mineral resin surfaces, which had nearly 2.0 log CFU/cm2 of residual staphylococci, or the abraded polycarbonate which had nearly 1.0 log CFU/cm2 of residual staphylococci. Chlorine was most effective on the mechanically polished stainless steel, the unabraded electropolished stainless steel, and the polycarbonate surfaces, reducing cell populations to less than 1.0 log CFU/cm2. Chlorine was less effective on abraded electropolished stainless steel and mineral resin surfaces, where populations remained greater than 1.0 log CFU/cm2. Sanitation with quaternary ammonium compound or chlorine reduced S. aureus populations more than 1,000-fold on all surfaces except unabraded mineral resin.

Bacterial Adhesion↗
PubMedDate not supplied

Phenol and HCl at 550 degrees C yield a large variety of chlorinated toxic compounds.

During the past decade it has been shown conclusively that the incineration of municipal and industrial wastes gives rise to emissions of chlorinated dibenzodioxins and dibenzofurans. However, the mechanism by which these toxic compounds are formed has not yet been fully established. Some researchers believe that the presence of organically bound chlorine is necessary, but others consider that inorganic forms of chlorine may also participate in the process. We now report the synthesis of a large number of chlorinated environmental pollutants in a simple high-temperature experiment. The results show that phenol and HCl are the most likely precursors of the chlorinated dibenzodioxins and dibenzofurans formed in the combustion of wastes. The dependence of the reaction on the concentration of HCl indicates a way of controlling the formation of these toxic compounds during incineration.

Chemical Phenomena↗
PubMed2006

Comparative application of solid-phase microextraction fibre assemblies and semi-permeable membrane devices as passive air samplers for semi-volatile chlorinated organic compounds. A case study on the landfill "Grube Antonie" in Bitterfeld, Germany.

Solid phase microextraction (SPME) fibres coated with Carbowax/divinylbenzene and semi-permeable membrane devices (SPMDs) of standard configuration were used to obtain time-weighted average (TWA) field air concentrations of selected chlorinated semi-volatile compounds on a landfill, where large amounts of lindane by-products were deposited, together with other hazardous chemical residues in the past. Additionally, spot sampling with SPME fibres was performed to identify the emission hotspot and sampling rates were determined/predicted for the substances of interest. Both samplers yield comparable TWA air concentrations of lindane and its isomers and of DDT with its metabolites and gain in certainty about the landfill as remaining source of air pollution with these compounds in the region. Both SPME fibres and SPMDs (respective their modifications) can be recommended as sampling tools in process studies and larger air monitoring programmes. However, further calibration studies and field tests are necessary to obtain reliable sampling rates for a wider range of semi-volatile compounds.

Air Pollutants↗
PubMed2003

Biofiltration of a mixture of volatile organic compounds on granular activated carbon.

The performance of a biofilter packed with Active Carbon (AC) was evaluated. The effluent (alcohol, ketones, esters, aromatic and chlorinated compounds) treated was a representative mixture of most common industrial emissions. To achieve a better knowledge of multicomponent adsorption mechanisms, and to underline the interest of inoculating AC, a control abiotic humidified filter had been operated in the same conditions as the biofilter. For a load of 110 g VOC m(-3) AC h(-1), after 55 days of operation, the removal efficiency was higher in the biotic than in the abiotic filter (85% vs 55%, respectively). Moreover, in the biofilter, at steady state, the elimination of all compounds was almost complete except for chlorinated compounds and p-xylene (removal efficiency of 25% and 64%, respectively). The microbial colonization of AC involved a decrease of the adsorption sites accessibility and enhanced the treatment of VOCs (volatile organic compounds) having a lower affinity for activated carbon. Moreover, while aromatic compounds and MIBK were eliminated along the overall height of the biofilter, pollutants with reduced affinity for AC, such as methanol, acetone, and halogenated compounds were only treated on the second half of the reactor. Thus, the affinity for activated carbon was an important parameter controlling the biodegradation process. Nevertheless, the use of AC as packing material in biofilters treating complex mixtures of VOCs is limited. Actually, similar removal efficiency could be reached, in the same conditions, for a biofilter packed with granular peat. Furthermore, for the biofilter packed with AC, the column height necessary to remove biodegradable compounds, with reduced affinity for the support, was important.

Adsorption↗
PubMed1990

[Formation of organochlorine compounds in chlorination of water].

This paper is a short version of a comprehensive literature study with the same title. During the chlorination of drinking, bathing and waste water a great number of halogenated compounds may be formed by the reaction of the disinfection agent with substances present in water. The haloforms which are often used as key compounds are only the tip of the iceberg. Reaction pathways and a selection of products are presented. The difficulty of assessing the health risk of a lifelong exposure to such compounds is pointed out. At present it doesn't however seem to be justified to abolish water chlorination because of hints to a possible weak carcinogenic action, because the arising bacterial risk would be irresponsible high.

Chlorine↗
PubMed1987

Mutagenicity of chlorinated polycyclic aromatic compounds.

The catalytic chlorination of polycyclic aromatic hydrocarbons leads to the formation of complex mixtures of isomers analogous to those found in fly ash samples of an incineration plant for radioactive waste. Therefore chlorination mixtures of chrysene, pyrene, and fluoranthene were analyzed and characterized by gas chromatography-mass spectrometry. Determination of the exact position of each chlorosubstituent within the molecule was not possible either by mass spectrometry or by comparison with well-defined methyl analogs. The toxic as well as mutagenic effects of such mixtures of isomers was compared with those of their parent hydrocarbons in the microtiter fluctuation test using Salmonella typhimurium TA 98 and TA 100 in a concentration range of 0.5 to 5.0 microgram/ml. No toxic effect could be observed, but the chlorinated products in contrast to their parent compounds were found to be strong mutagens to the S. typhimurium test strains and showed a positive response even without enzymatic activation. Frameshift mutations as well as base pair alterations were detected.

Animals↗
PubMed2004

Emission characteristics of PCDD/Fs, PCBs, chlorobenzenes, chlorophenols, and PAHs from polyvinylchloride combustion at various temperatures.

The effect of temperature on polyvinylchloride (PVC) combustion using a downstream tubular furnace was investigated for the formation of polycylcic aromatic hydrocarbons (PAHs) and chlorinated compounds. As the temperature increased, higher levels of PAHs were generated. Chlorinated compounds reached a peak at 600 degrees C, with low emissions recorded at 300 and 900 degrees C. There was a close correlation (R2 = 0.97) among polychlorinated biphenyls (PCBs), hexachlorobenzene, pentachlorobenzene, and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). PAHs at all temperatures were analyzed in the gas phase. PCDD/Fs and PCBs were emitted as a solid phase at 300 and 600 degrees C and as a gas phase at 900 degrees C. For some PAHs, chlorobenzenes, and PCDD/Fs, a mathematical equation between the gas and solid phase and the reciprocal temperature in semilog proportion was derived. The proposed equation, which is log (amount in gas phase/amount in solid phase) = -A/T + B, where T is the temperature of the furnace and A and B are constants, for these species relating their gas/solid distributions showed a good relationship.

Air Pollutants↗
PubMed2002

Strong emission of methyl chloride from tropical plants.

Methyl chloride is the largest natural source of ozone-depleting chlorine compounds, and accounts for about 15 per cent of the present atmospheric chlorine content. This contribution was likely to have been relatively greater in pre-industrial times, when additional anthropogenic sources-such as chlorofluorocarbons-were absent. Although it has been shown that there are large emissions of methyl chloride from coastal lands in the tropics, there remains a substantial shortfall in the overall methyl chloride budget. Here we present observations of large emissions of methyl chloride from some common tropical plants (certain types of ferns and Dipterocarpaceae), ranging from 0.1 to 3.7 microg per gram of dry leaf per hour. On the basis of these preliminary measurements, the methyl chloride flux from Dipterocarpaceae in southeast Asia alone is estimated at 0.91 Tg yr-1, which could explain a large portion of missing methyl chloride sources. With continuing tropical deforestation, natural sources of chlorine compounds may accordingly decrease in the future. Conversely, the abundance of massive ferns in the Carboniferous period may have created an atmosphere rich in methyl chloride.

Asia, Southeastern↗