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PubMed2003

[Occupational risk and evaluation of health damage in workers engaged in organochlorine compound production].

The authors analysed structure and degree of occupational risk in chlorine organic compounds production, revealed a combination of chemical, physical hazards with work burden and determined the work conditions as harmful and dangerous (3.2-3.4). With consideration of most medical and biologic parameters, high level of occupational risk appeared to correspond to significant (from medium to nearly complete) occupational conditionality of the disorders diagnosed. The suggested and approved method to determine occupational conditionality of health disorders at hazardous work conditions could serve as a basis for occupational medical standard.

Acetates↗
PubMed2005

Characterization of high molecular weight disinfection byproducts from chlorination of humic substances with/without coagulation pretreatment using UF-SEC-ESI-MS/MS.

Chlorinated disinfection byproducts (DBPs) generated from the reaction of the disinfectant chlorine with naturally occurring humic substances in raw water have been intensively studied over the past three decades, yet only a fraction of the total organic halogen (TOX) formed during chlorination has been chemically identified or even well characterized. The majority of the unknown portion of the TOX is likely attributable to high molecular weight (MW) DBPs (above 500), which may have potential adverse health effects. In this work, typically dosed chlorinated Suwannee River fulvic acid (SRFA) samples with and without coagulation pretreatment were separated and fractionated by using ultrafiltration (UF) and size exclusion chromatography (SEC) techniques. The SEC fractions corresponding to the high MW region were concentrated with nitrogen sparging and characterized by negative ion electrospray ionization mass spectrometry (ESI-MS) and ESI-MS/MS. The results demonstrate that the ESI-MS/MS precursor ion scan is an effective tool for the selective detection of the electrospray ionizable chlorine-containing compounds in a complex mixture. Many high MW chlorine-containing DBPs were tentatively found in the UF-SEC fractions of the chlorinated SRFA samples with/without coagulation pretreatment. The SEC-UV chromatograms and SEC-ESI-MS spectra show that coagulation could significantly reduce the formation of high MW chlorinated DBPs.

Benzopyrans↗
PubMed2000

Characterization of the naphthalene-degrading bacterium, Rhodococcus opacus M213.

Bacterial strain M213 was isolated from a fuel oil-contaminated soil in Idaho, USA, by growth on naphthalene as a sole source of carbon, and was identified as Rhodococcus opacus M213 by 16S rDNA sequence analysis and growth on substrates characteristic of this species. M213 was screened for growth on a variety of aromatic hydrocarbons, and growth was observed only on simple 1 and 2 ring compounds. No growth or poor growth was observed with chlorinated aromatic compounds such as 2,4-dichlorophenol and chlorobenzoates. No growth was observed by M213 on salicylate, and M213 resting cells grown on naphthalene did not attack salicylate. In addition, no salicylate hydroxylase activity was detected in cell free lysates, suggesting a pathway for naphthalene catabolism that does not pass through salicylate. Enzyme assays indicated induction of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase on different substrates. Total DNA from M213 was screened for hybridization with a variety of genes encoding catechol dioxygenases, but hybridization was observed only with catA (encoding catechol 1,2-dioxygenase) from R. opacus 1CP and edoD (encoding catechol 2,3-dioxygenase) from Rhodococcus sp. I1. Plasmid analysis indicated the presence of two plasmids (pNUO1 and pNUO2). edoD hybridized to pNUO1, a very large (approximately 750 kb) linear plasmid.

Biodegradation, Environmental↗
PubMed1991

Biogeochemical processes governing exposure and uptake of organic pollutant compounds in aquatic organisms.

This paper reviews current knowledge of biogeochemical cycles of pollutant organic chemicals in aquatic ecosystems with a focus on coastal ecosystems. There is a bias toward discussing chemical and geochemical aspects of biogeochemical cycles and an emphasis on hydrophobic organic compounds such as polynuclear aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated organic compounds used as pesticides. The complexity of mixtures of pollutant organic compounds, their various modes of entering ecosystems, and their physical chemical forms are discussed. Important factors that influence bioavailability and disposition (e.g., organism-water partitioning, uptake via food, food web transfer) are reviewed. These factors include solubilities of chemicals; partitioning of chemicals between solid surfaces, colloids, and soluble phases; variables rates of sorption, desorption; and physiological status of organism. It appears that more emphasis on considering food as a source of uptake and bioaccumulation is important in benthic and epibenthic ecosystems when sediment-associated pollutants are a significant source of input to an aquatic ecosystem. Progress with mathematical models for exposure and uptake of contaminant chemicals is discussed briefly.

Animals↗
PubMed1989

Formation of chlorinated PAH--a possible health hazard from water chlorination.

Four PAH compounds, fluorene, anthracene, fluoranthene and benzo(a)pyrene were dissolved in humus poor (lake) and humus rich water. The samples were chlorinated, stored for three days, and extracted with cyclohexane. Chlorinated derivatives of the four compounds were synthesised and used as calibration standards for quantitative analysis of the corresponding chlorinated PAH formed during the experiment. The synthesized chlorinated PAH were tested for mutagenic activity by the Ames test, and their octanol/water partition coefficient (Pow) were determined by thin layer chromatography. Chlorinated fluorene, fluoranthene and benzo(a)pyrene were formed during chlorination of PAH polluted lake water, but not during chlorination of the humus rich water samples. All chlorinated PAH except 9,10-dichloroanthracene, acted as strong mutagens both in the presence and in the absence of metabolic activation, while benzo(a)pyrene was the only mutagen active parent PAH. The determined Pow showed high lipophilicity for all chlorinated PAH. Theoretically determined bioconcentration factors (BCF) were found to be extremely high, and increased with increasing ring number and increasing number of chlorine atoms attached to the ring.

Anthracenes↗
PubMed2001

Determination of N-chloramines in As-samra chlorinated wastewater and their effect on the disinfection process.

Chlorine is the most widely used disinfectant of wastewater due to its capacity to inactivate most pathogenic microorganisms quickly. However, chlorine reacts with natural organic compounds present in wastewater to produce some undesirable organic byproducts. One such class of compounds is the nitrogenous compounds. The reaction between chlorine and compounds containing a nitrogen atom with one or more hydrogen atoms attached to it will form chloramines which have lower disinfection efficiency. Eighty percent of the wastewater generated in Jordan is treated at the Khirbet As-Samra wastewater treatment plant for eventual use in agriculture. In this study efficiency of chlorination was studied by collecting samples from the effluent of the treatment plant. The yield concentration of N-chloramines upon chlorination was determined. Efficiency of disinfection process as a function of contact time, concentration of chlorine dosage, concentration of nitrogenous compound and pH were studied. In this study, it has been found that at a chlorine dosage of 15 mg/L and contact time of 15 min, the percentage total coliform kill in As-samra wastewater sample was 100%. After addition of histidine, glycine and phenylalanine (15 mg/L in each case) to the wastewater sample, the percentage of total coliform kill dropped to 58, 78 and 79% respectively. When chlorine dosage was increased to 24 mg/L the percentage total coliform kill reached 96, 99 and 100% in wastewater samples treated with 5 mg/L histidine, glycine and phenylalanine, respectively. The percentage total coliform kill dropped to zero in wastewater samples treated with histidine, glycine and phenylalanine at a concentration of 30 mg/L each. This work supports the theory that amino acids and ammonia preferentially react with chlorine to form N-chloramine which significantly reduces the disinfection efficiency of the chlorination process.

Ammonium Chloride↗
PubMed2005

Oxidation of pharmaceuticals during water treatment with chlorine dioxide.

The potential of chlorine dioxide (ClO2) for the oxidation of pharmaceuticals during water treatment was assessed by determining second-order rate constants for the reaction with selected environmentally relevant pharmaceuticals. Out of 9 pharmaceuticals only the 4 following compounds showed an appreciable reactivity with ClO2 (in brackets apparent second-order rate constants at pH 7 and T = 20 degrees C): the sulfonamide antibiotic sulfamethoxazole (6.7 x 10(3) M(-1) s(-1)), the macrolide antibiotic roxithromycin (2.2 x 10(2) M(-1) s(-1)), the estrogen 17alpha-ethinylestradiol (approximately 2 x 10(5) M(-1) s(-1)), and the antiphlogistic diclofenac (1.05 x 10(4) M(-1) s(-1)). Experiments performed using natural water showed that ClO2 also reacted fast with other sulfonamides and macrolides, the natural hormones estrone and 17beta-estradiol as well as 3 pyrazolone derivatives (phenazone, propylphenazone, and dimethylaminophenazone). However, many compounds in the study were ClO2 refractive. Experiments with lake water and groundwater that were partly performed at microgram/L to nanogram/L levels proved that the rate constants determined in pure water could be applied to predict the oxidation of pharmaceuticals in natural waters. Compared to ozone, ClO2 reacted more slowly and with fewer compounds. However, it reacted faster with the investigated compounds than chlorine. Overall, the results indicate that ClO2 will only be effective to oxidize certain compound classes such as the investigated classes of sulfonamide and macrolide antibiotics, and estrogens.

Anti-Bacterial Agents↗
PubMed2003

Linear free-energy relationship analysis of the fate of chlorinated 1- and 2-carbon compounds by redox-manipulated smectite clay minerals.

This paper expands on earlier work on the effect of molecular structure on the fate of a series of chlorinated 1- and 2-carbon compounds (RCl), including carbon tetrachloride, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, hexachloroethane, trichloroethene, tetrachloroethene, trichloronitromethane, and trichloroacetonitrile, in the presence of unaltered (SWa-U) and reduced (SWa-R) ferruginous smectite. A linear free-energy relationships (LFERs) analysis was conducted to explain kinetic data for RCl adsorption and dechlorination. Correlation analyses based on RCl hydration energies, hydrolysis rate constants, or bond dissociation energies were significant (r2 > 0.87) for RCl adsorption by SWa-R but not so for RCl adsorption by SWa-U (r2 < 0.5). The most statistically significant relationships describing RCl kinetic data were achieved using multivariable regression analysis including RCl hydration energies (or hydrolysis rate constant) and bond dissociation energies for RCl heterolysis. The outcome of this study indicates that the oxidation state of structural Fe in the clay strongly influences RCl hydration. A mechanism consistent with the present LFERs analysis corresponds to RCl hydration as the limiting step for adsorption and dechlorination by redox-manipulated smectites.

Adsorption↗
PubMedDate not supplied

Organochlorine compounds: Risk of non-Hodgkin's lymphoma and breast cancer?

Organochlorines (i.e., synthetic chlorinated hydrocarbon compounds) are widespread, environmental contaminants that are present throughout the United States. Strong epidemiological evidence has linked occupational exposure to a high incidence of non-Hodgkin's lymphoma. Recently, it has been postulated that exposure to organochlorines increases the risk of developing breast cancer. Human data on this issue remain insufficient, but recent results are very consistent. Observations in human populations of the immunotoxic and hormone-mimicking properties of some organochlorines add biological plausibility to the epidemiologic findings. Limitations in our ability to measure organochlorine exposure still preclude a quantitative risk assessment, relative to these cancer endpoints. Public health action with respect to restriction of ongoing production and use of organochlorines, however, appears warranted for purposes of prevention.

Breast Neoplasms↗
PubMed1994

Rapid inactivation of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a potent mutagen in chlorinated drinking water, by sulfhydryl compounds.

The mutagenic activity of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), which is formed during chlorination of drinking water, was effectively inhibited by sulfhydryl compounds such as cysteine, cysteamine, glutathione, dithiothreitol and 2-mercaptoethanol. Preincubation of 0.5 micrograms MX with 15 micrograms cysteine (molar ratio 1:37) in a phosphate buffer (pH 6.0-8.0) at 37 degrees C for 15 min prior to exposure of bacterial cells depleted the mutagenic activity of MX. Together with the result showing a change in the UV spectra, it is suggested that sulfhydryl compounds inactivate MX by direct chemical interaction before MX induces DNA damage. On the other hand, a variety of antioxidants other than the sulfhydryl compounds showed no inhibitory effects. Investigation using structural analogs of cysteine revealed that the thiol moiety was indispensable for antimutagenic activity and the amino moiety appeared to enhance the MX-inactivating reaction of the SH group.

Antimutagenic Agents↗
PubMed2002

A chlorine isotope effect for enzyme-catalyzed chlorination.

Several chlorinated organic compounds (COCs) that have been detected in a wide range of human, animal, and environmental samples may be derived from natural or anthropogenic sources. To determine whether the Cl isotope ratios of these compounds could be used to differentiate sources, we investigated the chlorine isotope effect for enzyme-catalyzed chlorination. Two aromatic substrates, 1,3,5-trimethylbenzene (TMB) and 3,5-dimethylphenol (DMP), were treated with a chloroperoxidase isolated from the fungus Caldariomyces fumago. A kinetic isotope effect (KIE) (in terms of k35/k37) was calculated to be 1.012 for TMB and 1.011 for DMP. A similar reaction, but not catalyzed, with hypochlorite yielded a much smaller KIE. These results indicate that a substantial KIE exists for this process. Furthermore, natural COCs synthesized by this enzymatic pathway may have Cl isotope ratios that will be easily distinguished from anthropogenic COCs.

Chloride Peroxidase↗
PubMed2002

Online hourly determination of 62 VOCs in ambient air: system evaluation and comparison with another two analytical techniques.

This paper presents results of the processing and validation of data collected by an automatic gas chromatograph (AGC). This system was used to monitor 62 volatile organic compounds (VOCs) in urban air in the Basque Country, Spain. The nonpolar compounds (C2-C10) identified-paraffins, olefins, aromatics, and chlorinated compounds-accounted for 88% of the mass of total non-methane hydrocarbons (TNMHCs) in ambient air. The evaluation of linearity, precision, detection limits (DLs), and stability of retention times (RTs) indicates that the equipment is suitable for measuring ambient air automatically for prolonged periods (6 months). The calibration of the equipment using response factors calculated on the basis of the effective carbon number (ECN) showed variations of over 10% for acetylene, isoprene, and n-hexane. The results provided by the automatic chromatograph correlated significantly with simultaneous results from other widely used techniques for determining VOCs in ambient air: (1) portable GC, equipped with photoionization detector (PID), and (2) active adsorption on Tenax-TA followed by thermal desorption and chromatographic analysis.

Air Pollutants↗