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PubMed2005

Use of the Comet test and micronucleus assay on human white blood cells for in vitro assessment of genotoxicity induced by different drinking water disinfection protocols.

Surface water disinfection can lead to the formation of mutagenic/carcinogenic by-products derived from reactions with naturally occurring inorganic compounds. We investigated the feasibility and potential usefulness of an integrated approach to genotoxicity analysis of drinking water. The approach employed the Comet and micronucleus (MN) assays to evaluate the DNA and chromosomal damage produced by water extracts in human blood cells. Surface water samples from Lago Trasimeno (Italy) were collected in different seasons (July 2000, October 2000, February 2001, and June 2001), and samples were disinfected with sodium hypochloride (NaClO), chlorine dioxide (ClO(2)), or peracetic acid (PAA). Extracts of untreated and treated water were incubated with primary human leukocytes. The Comet assay revealed both strong seasonal variations and differences between samples processed by the three disinfection protocols. The three disinfectants increased the genotoxicity of the water collected in July 2000 and October 2000, with PAA producing the greatest amount of DNA damage. Extracts of raw water collected in February 2001 produced so much DNA damage that the relative genotoxic potentials of the three disinfectants could not be evaluated. No increase in MN frequency was detected in any of the samples. The multi-endpoint MN assay indicated, however, that our study samples (especially the sample collected in the February 2001) were cytotoxic. We conclude that this integrated approach to genotoxicity assessment may be useful both for the quality control of raw drinking water and to help compare the potential health risks associated with alternative disinfection processes.

Chlorine Compounds↗

PubMed2003

Combined physical-chemical and biological treatment of poorly biodegradable industrial effluents.

Effluents from small and medium sized chemical plants may contain significant amounts of poorly biodegradable aromatic compounds, which could negatively affect water quality and public health. This is a key environmental issue, particularly in areas where effluents are discharged into drinking water sources. Unfortunately, conventional biological treatment may not be able to meet discharge standards, and combined systems should be implemented. In this context, this paper presents experimental results on the application of a combined sequential ozonation-activated carbon-biological system to treat effluents containing chlorinated aromatic contaminants from chlorine based pulp bleaching. The experimental system consisted of an ozone bubble column reactor (0.3 dm3), an activated carbon fixed bed reactor (0.2 dm3), and an aerobic bioreactor (20 dm3). Ozone was produced from pure O2 using a generator rated at 2 mmol O3 h(-1). The bleaching effluent was pretreated and fed into the aerated sequencing batch bioreactor containing preconditioned biological sludge (3-4 g VSS dm(-3)), and cultured for 24 h. Samples of raw and treated effluents were assayed for biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total organic carbon (TOC), total phenols, and adsorbable organic halogens (AOX), using standard techniques. The presence of potential genotoxic activity in untreated and treated samples was assessed using the Ames tests. Results show that biological treatment of raw samples could not remove mutagenic activity on its own. On the other hand, ozonation followed by activated carbon treatment and biological treatment successfully removed genotoxicity in all cases. Reductions in BOD, COD, TOC, AOX, and phenols by biological treatment increased when samples were pretreated with ozone/activated carbon.

Bacteria, Aerobic↗

PubMed2003

Three new chlorine containing antibiotics from a marine-derived fungus Aspergillus ostianus collected in Pohnpei.

A marine bacterium Ruegeria atlantica (designated as strain TUF-D) was isolated from a glass plate submerged in the coastal water. Three new chlorine containing compounds (1 to approximately 3), together with penicillic acid (4) were obtained from a marine-derived fungus Aspergillus ostianus strain TUF 01F313 isolated from a marine sponge at Pohnpei as antibacterial components against R. atlantica. The structures of three new antibiotics were determined based on their spectral data as 8-chloro-9-hydroxy-8,9-deoxyasperlactone (1), 9-chloro-8-hydroxy-8,9-deoxyasperlactone (2), and 9-chloro-8-hydroxy-8,9-deoxyaspyrone (3). Compound 1 inhibited the growth of R. atlantica at 5 microg/disc (inhibition zone: 12.7 mm), while 2 and 3 were active at 25 microg/disc (10.1 and 10.5 mm, respectively).

4-Butyrolactone↗

PubMed1993

Immunotoxic potencies of polychlorinated biphenyl (PCB), dibenzofuran (PCDF) and dibenzo-p-dioxin (PCDD) congeners in C57BL/6 and DBA/2 mice.

The dose-dependent effects of a single acute exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), 1,2,3,7,9-PeCDF, 1,3,6,8-tetrachlorodibenzofuran (TCDF), 3,3',4,4',5-pentachlorobiphenyl (pentaCB), and 3,3,',4,4',5,5'-hexaCB on the suppression of the splenic plaque-forming cell (PFC) response to the T-cell-independent antigen trinitrophenyl-lipopolysaccharide were determined in C57BL/6 and DBA/2 mice. In addition, the induction of hepatic microsomal ethoxyresorufin O-deethylase (EROD) activity was also measured in these animals. 2,3,7,8-TCDD and 2,3,4,7,8-PeCDF were the most immunotoxic congeners in both strains of mice and with the exception of the latter congener, the ED50 values for each compound were lower in the C57BL/6 than the DBA/2 mice. 2,3,7,8-TCDD induced hepatic microsomal EROD activity in both strains of mice whereas the other congeners were considerably less active or inactive as inducers. The results of this study demonstrated that for the halogenated aromatic hydrocarbons the immunotoxic response was a more sensitive indicator of exposure than the induction of CYP1A1 activity. The rank order for the immunotoxic potencies of the chlorinated aromatic compounds used in this study was 2,3,7,8-TCDD approximately 2,3,4,7,8-PeCDF > 3,3',4,4',5-pentaCB approximately 3,3',4,4',5,5'-hexaCB > 1,2,3,7,9-PeCDF > 1,3,6,8-TCDF. The order of activity for these congeners was similar for other Ah receptor-mediated responses and these results coupled with the differential responsiveness of the C57BL/6 and DBA/2 mice confirms the role of aryl hydrocarbon (Ah) receptor in mediating the suppression of this T-cell-independent response.

Animals↗

PubMed1999

Decolorization and detoxification of extraction-stage effluent from chlorine bleaching of kraft pulp by Rhizopus oryzae.

Rhizopus oryzae, a zygomycete, was found to decolorize, dechlorinate, and detoxify bleach plant effluent at lower cosubstrate concentrations than the basidiomycetes previously investigated. With glucose at 1 g/liter, this fungus removed 92 to 95% of the color, 50% of the chemical oxygen demand, 72% of the adsorbable organic halide, and 37% of the extractable organic halide in 24 h at temperatures of 25 to 45 degrees C and a pH of 3 to 5. Even without added cosubstrate the fungus removed up to 78% of the color. Monomeric chlorinated aromatic compounds were removed almost completely, and toxicity to zebra fish was eliminated. The fungal mycelium could be immobilized in polyurethane foam and used repeatedly to treat batches of effluent. The residue after treatment was not further improved by exposure to fresh R. oryzae mycelium.

Aldehydes↗

PubMed2003

Characterization of Fe(III) reduction by chlororespiring Anaeromyxobacter dehalogenans.

Anaeromyxobacter dehalogenans strain 2CP-C has been shown to grow by coupling the oxidation of acetate to the reduction of ortho-substituted halophenols, oxygen, nitrate, nitrite, or fumarate. In this study, strain 2CP-C was also found to grow by coupling Fe(III) reduction to the oxidation of acetate, making it one of the few isolates capable of growth by both metal reduction and chlororespiration. Doubling times for growth of 9.2 and 10.2 h were determined for Fe(III) and 2-chlorophenol reduction, respectively. These were determined by using the rate of [(14)C]acetate uptake into biomass. Fe(III) compounds used by strain 2CP-C include ferric citrate, ferric pyrophosphate, and amorphous ferric oxyhydroxide. The addition of the humic acid analog anthraquinone 2,6-disulfonate (AQDS) increased the reduction rate of amorphous ferric iron oxide, suggesting AQDS was used as an electron shuttle by strain 2CP-C. The addition of chloramphenicol to fumarate-grown cells did not inhibit Fe(III) reduction, indicating that the latter activity is constitutive. In contrast, the addition of chloramphenicol inhibited dechlorination activity, indicating that chlororespiration is inducible. The presence of insoluble Fe(III) oxyhydroxide did not significantly affect dechlorination, whereas the presence of soluble ferric pyrophosphate inhibited dechlorination. With its ability to respire chlorinated organic compounds and metals such as Fe(III), strain 2CP-C is a promising model organism for the study of the interaction of these potentially competing processes in contaminated environments.

Acetic Acid↗

PubMedDate not supplied

Phytoremediation: a technology using green plants to remove contaminants from polluted areas.

Phytoremediation is an emerging cost-effective, non-intrusive, esthetically pleasing, and low cost technology using the remarkable ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. Phytoremediation technology is applicable to a broad range of contaminants, including metals and radionuclides, as well as organic compounds like chlorinated solvents, polychlorobiphenyls, polycyclic aromatic hydrocarbons, pesticides/insecticides, explosives, and surfactants. The use of plants to transport and concentrate metals from the soil into the harvestable parts of roots and above-ground shoots, usually called 'phytoextraction', has appeared on the scene as a valid alternative to traditional physicochemical remediation methods that do not provide acceptable solutions for the removal of metals from soils. Positive results are becoming available regarding the ability of plants to degrade certain organic compounds. Nonetheless, despite the firm establishment of phytoremediation technology in the literature and in extensive research study and in small-scale demonstrations, full-scale applications are currently limited to a small number of projects. At present, the phytoremediation of metal pollutants from the environment could be approaching commercialization.

Biodegradation, Environmental↗

PubMed2000

In vivo incorporation of radioactive 36Cl, a method for monitoring chloro compounds in biological material.

A new method for fast and easy monitoring of the presence, isolation, and separation of natural chloro compounds in plants is described. The method relies on the in vivo incorporation of radioactive 36Cl and new enhancement methods in autoradiographic technology. The method allows the time of exposure to be limited to 4 days and is thus suitable for routine purposes.

Autoradiography↗

PubMed1995

[Swimming-induced asthma].

Swimming is said to have low asthmogeneity especially when compared with other physical activities. Four young athletes who participated in heavy swimming exercise are reported as having symptoms of exercise-induced asthma (EIA). Three of them started to develop the symptoms after several years of training and had no former history of asthma. In the fourth, the asthma was diagnosed in childhood but the EIA-symptoms here exacerbated by swimming. All four experienced more symptoms when the air in the swimming pool was warm, or when there was a strong smell of chlorine. Two of the athletes reported having no symptoms when they swam in outdoor pools and had only minor symptoms, or none at all, when they did other formes of physical exercise, including running. In all four their swimming performance was hampered by their respiratory symptoms. Two of the swimmers improved when they inhaled steroids and adrenerg-beta 2 agonists, and continued their swimming carrier. The cases suggest that an irritant may provoke asthma symptoms in susceptible swimmers. Volatile compounds from chlorination of the pools are suspected as possible irritant agents.

Adolescent↗

PubMed1994

Effects of electron acceptors and donors on transformation of tetrachloromethane by Shewanella putrefaciens MR-1.

Transformation of chlorinated aliphatic compounds was examined in Shewanella putrefaciens strain MR-1, an obligately respiring facultative anaerobe. Under anaerobic conditions, MR-1 has been shown to transform tetrachloromethane to trichloromethane (24%), CO2 (7%), cell-bound material (50%) and unidentified nonvolatile products (4%). The highest rate and extent of transformation were observed with MR-1 cells grown under iron(III)-respiring conditions. Lactate, formate and hydrogen were the most effective electron donors. Tetrachloromethane was not degraded in the presence of oxygen. Transformation of other chlorinated methanes and ethenes was not observed.

Biodegradation, Environmental↗

PubMed2002

The interference of 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) in the detection of strong mutagen MX.

The MX formation potential of some compounds belong to benzoic acids, benzoic aldehydes and phenols families was investigated. Only some structures with aldehyde group can form MX, which is inconsistent with other research. A new compound 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) was found. It will seriously interfere with the detection of MX when the GC/MS instrument is operated in select ion monitoring mode because its retention time is very close to that of methylated MX and it has a set of characteristic ions m/z 199, 201, 203, which is widely used in the detection of MX. The detection of COHC has not been reported previously. However, according to its formation mechanism it will widely occur in chlorinated drinking and humic water. Due to the presence of COHC, some of the former research results on MX should be revised.

Alkenes↗

PubMed2005

Modelling the interaction of steroid receptors with endocrine disrupting chemicals.

BACKGROUND: The organic polychlorinated compounds like dichlorodiphenyltrichloroethane with its metabolites and polychlorinated biphenyls are a class of highly persistent environmental contaminants. They have been recognized to have detrimental health effects both on wildlife and humans acting as endocrine disrupters due to their ability of mimicking the action of the steroid hormones, and thus interfering with hormone response. There are several experimental evidences that they bind and activate human steroid receptors. However, despite the growing concern about the toxicological activity of endocrine disrupters, molecular data of the interaction of these compounds with biological targets are still lacking. RESULTS: We have used a flexible docking approach to characterize the molecular interaction of seven endocrine disrupting chemicals with estrogen, progesterone and androgen receptors in the ligand-binding domain. All ligands docked in the buried hydrophobic cavity corresponding to the hormone steroid pocket. The interaction was characterized by multiple hydrophobic contacts involving a different number of residues facing the binding pocket, depending on ligands orientation. The EDC ligands did not display a unique binding mode, probably due to their lipophilicity and flexibility, which conferred them a great adaptability into the hydrophobic and large binding pocket of steroid receptors. CONCLUSION: Our results are in agreement with toxicological data on binding and allow to describe a pattern of interactions for a group of ECD to steroid receptors suggesting the requirement of a hydrophobic cavity to accommodate these chlorine carrying compounds. Although the affinity is lower than for hormones, their action can be brought about by a possible synergistic effect.

Amino Acid Sequence↗

PubMed1998

Screening of xenobiotic compounds degrading microorganisms using biosensor techniques.

A screening device based on microorganisms immobilised onto a Clark-type oxygen electrode was used to monitor the potential of these microorganisms for the degradation and detection of xenobiotic compounds especially their chlorinated derivatives. The sensitivity and specificity of various species of Pseudomonas, Sphinomonas, Ralstonia, Rhodococcus were characterised in relation to xenobiotic compounds by using biosensor techniques. The following groups of xenobiotics were subjects of investigation: chlorophenols, chlorobenzoates, 2,4-D, PCB, dibenzofurane and their putative intermediates. Using this simple setup it proved possible to screen microbial strains for their potential to catabolize aromatic and chloroaromatic compounds under oxygen consumption. In a kinetic regime, a reproducible signal was obtained within minutes. Based on these results the sensor technique was a suitable method for the rapid characterization of microorganisms and allowed to gather information about the substrate spectrum.

2,4-Dichlorophenoxyacetic Acid↗

PubMed1993

Sporocidal properties of peracetic acid and hydrogen peroxide, alone and in combination, in comparison with chlorine and formaldehyde for ultrafiltration membrane disinfection.

The sporocidal properties of peracetic acid, hydrogen peroxide, chlorine, and formaldehyde were compared in vitro using a dilution-neutralization micromethod. A combination of peracetic acid and hydrogen peroxide was also tested to assess their interactions. The activities of these agents, which are widely used as disinfectants, were evaluated against Bacillus spore isolates found on stored membranes and collection cultures. Peracetic acid and chlorine exhibited an excellent antimicrobial activity, with a destruction of 10(5) spores/mL after 5 min of contact. Generally the effects of the biocides tested were time dependent. The sporocidal activities of hydrogen peroxide and formaldehyde were the lowest. The combination of peracetic acid and hydrogen peroxide, tested by a checkerboard micromethod, was found to be synergistic. The minimal sporocidal concentration (MSC) was established in terms of time for each biocide. The lowest MSC values for peracetic acid, hydrogen peroxide, chlorine, and formaldehyde were 168-336 ppm (1-2 h of contact), 5625-11250 ppm (5-7 h), 168-336 ppm (2-3 h), and 1875-3750 ppm (5-30 min), respectively. The MSC of a biocide combination of peracetic acid and hydrogen peroxide showed that synergy was maintained with increasing contact time and that the MSC could be reduced by two to eight times when compared with those of the biocides alone. Optimal concentrations and contact times of those chemicals that were promising in vitro were then tested for their ability to disinfect ultrafiltration membranes. The sporocidal activities of peroxide compounds and chlorine were confirmed and the synergism between peracetic acid and hydrogen peroxide was also maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacillus↗

PubMed1978

Modification of M-FC medium by eliminating rosolic acid.

Eliminating rosolic acid from M-FC medium improves the MFC procedure by allowing higher fecal coliform colony recoveries with greater ease in counting. Samples of unchlorinated and chlorinated domestic sewage, creek, lake, and river water were analyzed for fecal coliforms by standard procedures. Results of 200 comparisons of fecal coliform counts on M-FC medium without and with rosolic acid showed that higher counts were obtained 71% of the time when rosolic acid was excluded without an overgrowth of background colonies. Results from analyzing chlorinated sewage showed that eliminating rosolic acid improved the recovery of fecal coliform bacteria by 49%. A total of 1,675 blue colonies and 766 nonblue colonies were verified. Of the 1,675 blue colonies, 1,566 were confirmed as fecal coliform bacteria, for a verification of 93.5%. The percent verification of nonblue colonies as noncoliform bacteria was 84.2% (644/766).

Aurintricarboxylic Acid↗

PubMedDate not supplied

Regiospecific dechlorination of spiked tetra- and trichlorodibenzo-p-dioxins by anaerobic bacteria from PCDD/F-contaminated Spittelwasser sediments.

Samples were taken from sediment of the River Spittelwasser (district Bitterfeld, Germany), which is highly polluted with PCDD/Fs and other chloroorganic compounds. The sediment cores were separated into 10-20 cm thick layers, spiked with 50 microM of 1,2,3,4-tetrachlorodibenzo-p-dioxin and incubated for 8 months under anaerobic conditions in the presence of cosubstrates. Reductive dechlorination of the tetrachlorinated congener and formation of tri- and dichlorinated products were observed in all biologically active incubations. Analysis of subcultures spiked with 1,2,3- and 1,2,4-trichlorodibenzo-p-dioxin, respectively, revealed two different dechlorination pathways within the sediment cores. Pathway M was characterized by the simultaneous dechlorination of peri- and lateralchlorine atoms, whereas sequence SP was restricted to the dechlorination at positions flanked by chlorine atoms on both sides.

Bacteria, Anaerobic↗

PubMed2001

Methods for the stable isotopic analysis of chlorine in chlorate and perchlorate compounds.

Chlorate and perchlorate compounds, used as herbicides, solid fuel propellants, and explosives, are increasingly recognized as pollutants in groundwater. Stable isotope characterization would permit both environmental monitoring of extent of remediation and forensic characterization. Stoichiometric reduction to chloride (greater than 98% yield), by Fe(II) for chlorate and alkaline fusion-decomposition for perchlorate, allows analysis by standard methods to give highly reproducible and accurate delta37Cl results (0.05/1000, 2 x standard error). Analysis of various compounds from different suppliers yielded delta37Cl values for chlorate samples near to +0.2/1000 (SMOC), but one has within-sample heterogeneity of 0.5/1000, possibly due to crystallization processes during manufacture. Results for perchlorate samples also are generally near +0.2/1000, but one is +2.3/1000 (SMOC). The initial results suggest that both forensic and environmental applications might be feasible.

Chlorates↗

PubMed2004

Inhibition of constitutive signal transducer and activator of transcription 3 activation by novel platinum complexes with potent antitumor activity.

DNA-alkylating agents that are platinum complexes induce apoptotic responses and have wide application in cancer therapy. The potential for platinum compounds to modulate signal transduction events that contribute to their therapeutic outcome has not been extensively examined. Among the signal transducer and activator of transcription (STAT) proteins, Stat3 activity is frequently up-regulated in many human tumors. Various lines of evidence have established a causal role for aberrant Stat3 activity in malignant transformation and provided validation for its targeting in the development of small-molecule inhibitors as novel cancer therapeutics. We report here that platinum-containing compounds disrupt Stat3 signaling and suppress its biological functions. The novel platinum (IV) compounds, CPA-1, CPA-7, and platinum (IV) tetrachloride block Stat3 activity in vitro at low micromolar concentrations. In malignant cells that harbor constitutively activated Stat3, CPA-1, CPA-7, and platinum (IV) tetrachloride inhibit cell growth and induce apoptosis in a manner that reflects the attenuation of persistent Stat3 activity. By contrast, cells that do not contain persistent Stat3 activity are marginally affected or are not affected by these compounds. Moreover, CPA-7 induces the regression of mouse CT26 colon tumor, which correlates with the abrogation of persistent Stat3 activity in tumors. Thus, the modulation of oncogenic signal transduction pathways, such as Stat3, may be one of the key molecular mechanisms for the antitumor effects of platinum (IV)-containing complexes.

Animals↗