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PubMed2004

Safety assessment of dichlorophene and chlorophene.

Dichlorophene is a halogenated phenolic compound that functions as a bacteriocide and fungicide in cosmetics. Chlorophene is a halogenated phenolic compound that functions as a biocide and preservative in cosmetics. Dichlorophene was reported to be used in a total of five cosmetic formulations at concentrations of 0% to 1.0%, but Chlorophene was not reported to be used. Dichlorophene is prohibited for use in cosmetic ingredients in Japan. In Europe, the maximum authorized concentration allowed for Dichlorophene is 0.5% and for Chlorophene is 0.2%. The major impurity of Dichlorophene is the trimer 4-chloro-2,6-bis(5-chloro-2-hydroxybenzyl)phenol. In rats, Dichlorophene sulfate, Dichlorophene monoglucuronide, and Dichlorophene diglucuronide were the major metabolites of Dichlorophene and were excreted, mainly in the urine. The glucuronic acid conjugate, the sulfate ester conjugate, and two minor metabolites of Chlorophene were the metabolites found in rat urine. Chlorophene was incompletely absorbed through the rat skin. These chemicals exhibited low toxicity in acute oral toxicity studies in several animal species. Some evidence of toxicity with both chemicals was found in short-term oral toxicity studies in mice and rats; nephropathy was the principal finding. Chronic toxicity data were not available for Dichlorophene. Rats and mice dosed with Chlorophene for 2 years had a dose-related and sex-related increase in the severity of nephropathy. In animal tests, Dichlorophene and Chlorophene were ocular irritants. No inhalation toxicity data were available for these ingredients. Dichlorophene up to 10% concentration resulted in no to minimal irritation when applied to the intact and abraded skin of rabbits. Chlorophene was severely irritating to rabbits in most dermal irritation studies. Studies on guinea pigs gave positive and negative results in sensitization tests of Dichlorophene. A dose-related contact hypersensitivity response to Chlorophene was reported in mice. No reproductive or developmental toxicity data were available for Dichlorophene, but there was some evidence of non-dose-dependent developmental toxicity with Chlorophene in rabbits. Dichlorophene was positive in the Ames mutagenicity assay, but not in mammalian or fruit fly test systems. Chlorophene was mutagenic in four in vitro mammalian test systems. Carcinogenicity studies for Dichlorophene were not found. Neoplasms were not observed in rats treated with Chlorophene for 2 years; however a significant incidence of neoplasms was observed in mice so treated. A 1-year National Toxicology Program (NTP) study concluded that Chlorophene was a cutaneous irritant and a weak skin tumor promoter but had no activity as an initiator or complete carcinogen. Dichlorophene was not a sensitizer in clinical dermal sensitization tests. Some reactions to Chlorophene occurred in some, but not all, clinical dermal sensitization tests. Positive photopatch tests to Dichlorophene were found in 13/469 patients. Although these ingredients were ocular irritants at high concentrations, the risk at concentrations which are actually used in cosmetic formulations was uncertain. Overall, the available data were insufficient to support safety of Dichlorophene or Chlorophene. Additional data needed include (1) method of manufacture and impurities data (especially the trimer in Dichlorophene); (2) photosensitization and photocarcinogenicity data for Dichlorophene; (3) dermal reproductive and developmental toxicity data for Dichlorophene (as a function of dose); and (4) ocular irritation at concentration of use, if available.

Administration, Cutaneous↗
PubMed1985

Laboratory and human studies on polychlorinated biphenyls (PCBs) and related compounds.

Similar qualitative toxic effects have been observed in animals for a class of halogenated aromatic compounds, which include the halogenated biphenyls, naphthalenes, dibenzodioxins, and dibenzofurans. All of these compounds are lipid soluble and persist in the environment and in mammals. The polybrominated biphenyls (PBBs) are the most persistent. They are predominantly stored in fatty tissue; they pass the placenta and are excreted in milk. Some isomers of the halogenated biphenyls are more toxic than others. With some exceptions, the more toxic isomers are retained longer in tissues and are also the carcinogenic components of the mixture. Most of these chemicals seem to be promoters of carcinogenesis in animals rather than initiators. An array of toxic effects in laboratory animals has been ascribed to these compounds and numerous reviews summarizing this information are available. Less information is available on the human health effects of environmental and occupational exposure. Results of recent studies in animals to further elucidate the effects of these chemicals are presented, and results from some human studies conducted in the United States are reviewed.

Accidents↗
PubMed1995

Identification of two binding proteins for halogenated aromatic hydrocarbons in the hard-shell clam, Mercenaria mercenaria.

Earlier studies have reported an unusually high incidence of gonadal tumors in marine bivalves in areas of potentially high exposure to herbicides including 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophe-noxyacetic acid. Some herbicides can be contaminated by halogenated aromatic compounds including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Most of the effects of planar halogenated aromatic compounds, including carcinogenic effects in vertebrates, appear to be mediated through binding to the aryl hydrocarbon receptor. The current study investigated whether halogenated aromatic hydrocarbon-binding proteins are present in the marine bivalve, Mercenaria mercenaria. We used the TCDD photoaffinity analog 2-azido-3-[125I]-iodo-7, 8-dibromodibenzo-p-dioxin to detect the presence of two proteins (28 and 39 kDa) in cytosols prepared from M. mercenaria that specifically bound this ligand. Expression of these proteins is tissue-dependent with the highest concentrations being observed in gill and gonadal tissue. Gonadal tissue also exhibited gender-specific expression with female clams exhibiting higher levels of the 39-kDa protein. Gender-and tissue-specific expression are consistent with the hypothesis that these proteins might be involved in the carcinogenic response observed in clams exposed to herbicides.

Affinity Labels↗
PubMed1983

Effects of 2-bromoethanesulfonic Acid and 2- chloroethanesulfonic Acid on acetate utilization in a continuous-flow methanogenic fixed-film column.

2-Bromoethanesulfonic acid (BESA) and 2-chloroethanesulfonic acid (CESA) have been reported to be potent inhibitors of methane formation during methanogenic decomposition in batch cultures. However, in a laboratory-scale continuous-flow methanogenic fixed-film column containing a predominance of acetate-decarboxylating methanogens, BESA at 6 x 10 M produced only a 41% inhibition of acetate utilization, and CESA at 5.4 x 10 M produced a 37% inhibition of acetate utilization. BESA and CESA concentrations were not monitored in the effluent, so their fate is unknown. The organisms in the column were capable of degrading trace halogenated aliphatic compounds ( approximately 30 mug/liter) with acetate (100 mg/liter) as the primary substrate. Previous exposure of the cells to halogenated organic compounds may have conferred resistance to BESA and CESA. Degradation of the inhibitor compounds is another possible explanation for the observed effects.

Journal Article↗
PubMed2002

Two-dimensional on-line detection of brominated and iodinated volatile organic compounds by ECD and ICP-MS after GC separation.

Inductively coupled plasma-mass spectrometry (ICP-MS) was coupled to a gas chromatographic (GC) system with electron capture detector (ECD), which enables relatively easy characterization and quantification of brominated and iodinated (halogenated) volatile organic compounds (HVOCs) in aquatic and air samples. The GC-ECD system is connected in series with an ICP-MS by a directly heated transfer line and an outlet port-hole for elimination of the ECD make-up gas during ignition of the plasma. The hyphenated GC-ECD/ICP-MS system provides high selectivity and sensitivity for monitoring individual HVOCs under fast chromatographic conditions. The ECD is most sensitive for the detection of chlorinated and brominated but the ICP-MS for iodinated compounds. The greatest advantage of the use of an ICP-MS is its element-specific detection, which allows clear identification of compounds in most cases. The absolute detection limits for ICP-MS are 0.5 pg for iodinated, 10 pg for brominated, and 50 pg for chlorinated HVOCs with the additional advantage that calibration is almost independent on different compounds of the same halogen. In contrast to that detection limits for ECD vary for the different halogenated compounds and lie in the range of 0.03-11 pg. The two-dimensional GC-ECD/ICP-MS instrumentation is compared with electron impact mass spectrometry (EI-MS) and microwave induced plasma atomic emission detection (MIP-AED). Even if EI-MS has additional power in identifying unknown peaks by its scan mode, the detection limits are much higher compared with GC-ECD/ICP-MS, whereas the selective ion monitoring mode (SIM) reaches similar detection limits. The MIP-AED detection limits are at the same level as EI-MS in the scan mode.

Air Pollutants↗
PubMed1990

Potential uses of combined halogen disinfectants in poultry processing.

Five organic N-halamine compounds (combined halogen disinfectants) were compared for their bactericidal activities against Salmonella typhimurium under controlled pH and temperature. All five compounds were effective as bactericides in demand-free buffers ranging from pH 5.0 to 9.0 and treatment temperatures from 4 to 48 C. The range of contact times necessary for a 99.9999% inactivation of viable cells was from .22 to 29 min, depending on the halogen concentration, temperature, and pH of the demand-free buffer. Two of the compounds (3-chloro-4,4-dimethyl-2-oxazolidinone and 1,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone) were found to have considerable promise in high-temperature applications, and a third compound (1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone) was more suitable for low-temperature treatments.

Animals↗
PubMed1989

[Hydrocarbons and chlorinated hydrocarbons in groundwater].

The contribution deals with the following topics: --Microbiological in situ investigations of polluted ground water aquifers in order to develop a concept for biological remediation. --Removal of organic and halogenated organic compounds from ground water using methods which are common in the drinking water treatment (sand-fastfiltering, immobilized reactors). --Removal of organic and halogenated organic compounds from ground water using methods which are common in sewage treatment (activated sludge, suspension reactors). The conclusion has been drawn that there are many microbiological methods existing which can be used to remove the above contaminants from soil and ground water environments.

Bacteria↗
PubMed1990

Combined halogen disinfectants in poultry processing.

Three organic N-halamine compounds (combined halogen disinfectants) were compared with free chlorine (as calcium hypochlorite) as bactericides against Salmonella typhimurium and unidentified normal poultry bacterial flora under controlled conditions of pH, temperature, and halogen demand similar to those encountered in poultry processing. Two of the compounds (3-chloro-4,4-dimethyl-2-oxazolidinone and 1,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone) at a concentration of 50 mg/L were found to cause a 99.9999% decline in viable organisms in less than 1 min at 48 C, whereas a third compound (1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone) was found to be less suitable (5.6 min to 99.9999% decline under the same conditions).

Animals↗
PubMed1997

Inhibitory effects of anesthetics and ethanol on muscarinic receptors expressed in Xenopus oocytes.

Anesthetics (and ethanol) are known to produce amnesia as well as immobilization. Recent identification of a nonimmobilizing (nonanesthetic) agent (F6 or 1,2-dichlorohexafluorocyclobutane) that impairs learning and memory suggests that distinct mechanisms may be responsible for these two actions of anesthetic agents. Muscarinic receptors are believed to play a role in memory and learning, and we asked if a specific subtype of these receptors is affected by anesthetics as well as the new nonanesthetic. We investigated the effects of halothane, a novel halogenated anesthetic compound F3 (1-chloro-1,2,2-trifluorocyclobutane) and ethanol on acetylcholine-induced current mediated by a muscarinic m1 receptor expressed in Xenopus oocytes. We also studied the effects of halogenated nonanesthetic compounds, F6 and F8 (2,3-chlorooctafluorobutane) on muscarinic m1 receptors. Halothane, F3, F6 and ethanol inhibited muscarinic m1 receptor-induced Ca2+-dependent Cl- currents at pharmacologically relevant concentrations. F8 had no effect on acetylcholine-induced muscarinic m1 receptor function. The protein kinase C inhibitor, bisindolylmaleimide I (GF109203X), enhanced the acetylcholine-induced current and the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), inhibited this current. GF109203X abolished the inhibitory effects of halothane, F3 and ethanol on muscarinic m1 receptors but had no effect on actions of F6. These results demonstrate that anesthetics and a nonanesthetic inhibit the function of muscarinic m1 receptors and suggest activation of protein kinase C as the mechanism of action of anesthetics and ethanol on these receptors.

Anesthetics, Inhalation↗
PubMed2006

A novel on-site system for the treatment of pharmaceutical laboratory wastewater by supercritical water oxidation.

For the on-site treatment of laboratory waste, we have been developing a compact-sized reaction system for the treatment of laboratory wastewater using supercritical water oxidation (SCWO) technology. Pharmaceutical laboratory wastewater is one of the most difficult wastewaters to treat because of its high concentration of halogenated organic compounds. We proposed a new cascade process in which two reactors are consecutively combined, carrying out hydrolysis in the first reactor followed by SCWO in the second reactor, for the complete removal of halogenated organic compounds. Dichloromethane was chosen as a representative model of chlorinated compounds. There have been many previous studies on the hydrolysis of dichloromethane, which results in the coproduction of formaldehyde and HCl. However, there has been less investigation on the kinetics of formaldehyde oxidation in supercritical water. In this study, we focus on the oxidation of formaldehyde in supercritical water with and without a catalyst. As a result, formaldehyde can be completely decomposed at 400 degrees C and 25 MPa within a very short contact time in a heterogeneous system with a MnO(2) catalyst.

Drug Compounding↗
PubMed2005

Screening of organic halogens and identification of chlorinated benzoic acids in carbonaceous meteorites.

The occurrence of halogenated organic compounds measured as a sum parameter and the evidence of chlorinated benzoic acids in four carbonaceous meteorites (Cold Bokkeveld, Murray, Murchison and Orgueil) from four independent fall events is reported. After AOX (Adsorbable organic halogen) and EOX (Extractable organic halogen) screening to quantify organically bound halogens, chlorinated organic compounds were analyzed by gas chromatography. AOX concentrations varying from 124 to 209 microg Cl/g d.w. were observed in carbonaceous meteorites. Ion chromatographic analysis of the distribution of organically bound halogens performed on the Cold Bokkeveld meteorite revealed that chlorinated and brominated organic compounds were extractable, up to 70%, whereas only trace amounts of organofluorines could be extracted. Chlorinated benzoic acids have been identified in carbonaceous meteorite extracts. Their presence and concentrations raise the question concerning the origin of halogenated, especially chlorinated, organic compounds in primitive planetary matter.

Carbon↗
PubMed1997

Reduction of 3-chlorobenzoate, 3-bromobenzoate, and benzoate to corresponding alcohols by Desulfomicrobium escambiense, isolated from a 3-chlorobenzoate-dechlorinating coculture.

An anaerobic bacterial coculture which dechlorinated 3-chlorobenzoate (3CB) to benzoate was obtained by single-colony isolation from an anaerobic bacterial consortium which completely degraded 3CB in defined medium. Of 29 additional halogenated aromatic compounds tested, the coculture removed the meta halogen from 2,3- and 2,5-dichlorobenzoate, 3-bromobenzoate (3BB), 5-chlorovanillate (5CV), and 3-chloro-4-hydroxybenzoate. Dechlorinating activity in the coculture required the presence of pyruvate. 5CV was also O-demethoxylated. The coculture contained two cell types: a short, straight gram-negative rod and a long, thin, curved gram-positive rod. The short rod, Desulfomicrobium escambiense, was recently isolated and identified as a new sulfate-reducing bacterial species (B. R. Sharak Genthner, S. D. Friedman, and R. Devereux, Int. J. Syst. Bacteriol. 47:889-892, 1997; B. R. Sharak Genthner, G. Mundfrom, and R. Devereux, Arch. Microbiol. 161:215-219, 1994). D. escambiense did not dehalogenate any of the compounds dehalogenated by the coculture, nor dit it O-demethoxylate 5CV or vanillate. However, D. escambiense reduced 3CB, EBB, and benzoate to their respective benzyl alcohols. Reduction to alcohols required the presence of pyruvate, which was transformed to acetate, lactate, and succinate in the presence of absence of 3CB, 3BB, or benzoate. Alcohol formation did not occur in pyruvate-sulfate medium. Under these conditions, sulfate was preferentially reduced. Other electron donors that supported the growth of D. escambiense during sulfate reduction did not support benzoate reduction to benzyl alcohol.

Benzoates↗