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PubMed1971

Chemical wastes in the sea: new forms of marine pollution.

Drums containing chemical wastes have been found in and along the North Sea. The wastes were analyzed and were found to include lower chlorinated aliphatic compounds, vinyl esters, chlorinated aromatic amines and nitrocompounds, and the insecticide endosulfan. Because dropping these drums into the sea endangers the environment and results in damage to fishing operations, measures should be taken to stop this practice.

Acetates↗
PubMed2005

Combustion of chlorinated volatile organic compounds (VOCs) using bimetallic chromium-copper supported on modified H-ZSM-5 catalyst.

The paper reports on the performance of chromium or/and copper supported on H-ZSM-5(Si/Al = 240) modified with silicon tetrachloride (Cr1.5/SiCl4-Z, Cu1.5/SiCl4-Z and Cr1.0Cu0.5/SiCl4-Z) as catalysts in the combustion of chlorinated VOCs (Cl-VOCs). A reactor operated at a gas hourly space velocity (GHSV) of 32,000 h(-1), a temperature between 100 and 500 degrees C with 2500 ppm of dichloromethane (DCM), trichloromethane (TCM) and trichloroethylene (TCE) is used for activity studies. The deactivation study is conducted at a GHSV of 3800 h(-1), at 400 degrees C for up to 12 h with a feed concentration of 35,000 ppm. Treatment with silicon tetrachloride improves the chemical resistance of H-ZSM-5 against hydrogen chloride. TCM is more reactive compared to DCM but it produces more by-products due to its high chlorine content. The stabilization of TCE is attributed to resonance effects. Water vapor increases the carbon dioxide yield through its role as hydrolysis agent forming reactive carbocations and acting as hydrogen-supplying agent to suppress chlorine-transfer reactions. The deactivation of Cr1.0Cu0.5/SiCl4-Z is mainly due to the chlorination of its metal species, especially with higher Cl/H feed. Coking is limited, particularly with DCM and TCM. In accordance with the Mars-van Krevelen model, the weakening of overall metal reducibility due to chlorination leads to a loss of catalytic activity.

Air Pollutants, Occupational↗
PubMed1984

Myeloperoxidase-dependent fluorescein chlorination by stimulated neutrophils.

Hypochlorous acid (HOC1) rapidly chlorinates fluorescein compounds forming, sequentially, the corresponding 4'-chlorofluorescein and 4',5'-dichlorofluoresceins. Chlorination by cell-free myeloperoxidase-catalyzed chloride peroxidation systems gives rise to these compounds as well as variable amounts of isomeric compounds chlorinated in the 2'- and 2',7'-positions. The fluorescence intensity of the dianionic form of the dye is partially quenched upon chlorination, and its proton equilibrium constants are shifted to more acidic values. Fluorescein covalently bound to zymosan (5-isothiocyanatofluorescein-zymosan) also formed these products when the unopsonized particles were incubated with phorbol myristate acetate- or N-formyl-methionyl-leucyl-phenylalanine-stimulated human neutrophils. This reaction was associated with a fall in fluorescence intensity, which was not observed when cells from individuals with chronic granulomatous disease or myeloperoxidase deficiency were used or when azide or catalase were added to the reaction medium. Fluorescent changes accompanying phagocytosis of serum-opsonized 5-isothiocyanatofluorescein-zymosan were also consistent with chlorination of the label; the changes were shown to be myeloperoxidase-dependent by use of myeloperoxidase-deficient or azide-treated cells. Oxidative bleaching of the structurally similar sulfonphthalein dyes by HOCl also occurs at rates which parallel the dye basicities. Results are discussed in relation to the use of fluoresceinated particles and sulfonphthalein dyes in the measurement of intraphagosomal acidification.

Chromatography, High Pressure Liquid↗
PubMed2004

Anaerobic transformation of compounds of technical toxaphene. 2. Fate of compounds lacking geminal chlorine atoms.

The major toxaphene metabolites in sediment and soils (2-exo,3-endo,6-exo,8,9,10-hexachlorobornane [B6-923] and 2-endo,3-exo,5-endo,6-exo,8,9,10-heptachlorobornane [B7-1001]) were incubated with the isolated gram-negative bacterium Dehalospirillum multivorans. Within 14 d, biotransformation of B7-1001 was nearly quantitative, resulting in two penta- and six hexachlorobornanes, as well as one unsaturated hexachloro compound of technical toxaphene. The major transformation product (approximately 50% of all metabolites) was identified as 2-exo,3-endo,5-exo,8,9,10-hexachlorobornane (B6-903). Abiotic dehydrochlorination of B7-1001 with methanolic KOH resulted in the formation and subsequent identification of the lone unsaturated compound as 2,5-endo,6-exo,8,9,10-hexachloroborn-2-ene. Thus, dehydrochlorination was found to be a minor process of the anaerobic transformation of toxaphene. Biotransformation of 70% of amended B6-923 within 14 d demonstrated that reductive dechlorination was not exclusively associated with geminal Cl atoms, as previously suggested. Three pentachlorobornanes were identified as transformation products, one of which was identical with a transformation product of B7-1001. This commonality unequivocally proves this metabolite to be 2-exo,3-endo,8,9,10-pentachlorobornane. Fifteen previously unknown metabolites of B6-923, B7-1001, and other toxaphene compounds identified in this study were detected in sediment from Lake Ontario (Canada), underscoring the importance of microbial toxaphene transformation in natural, aquatic environments.

Anaerobiosis↗
PubMed2003

Partitioning of persistent organic pollutants in grey seal (Halichoerus grypus) mother-pup pairs.

Phocid seals have lipid rich milk, which is known to serve as a transfer medium through which persistent organic pollutants (POPs) move from mother to offspring during lactation. However, knowledge on this generational transfer of different POPs and the partitioning of these compounds in maternal and offspring tissues over the course of the lactation are limited. In this study we examined the qualitative and quantitative partitioning of a range of chlorinated POPs in maternal blubber, blood and milk as well as in pup blubber, collected early in the lactation period and late in the lactation period. In the lactating female, the high-chlorinated and hydrophobic compounds were passed less efficiently into the milk than the low-chlorinated compounds and more water-soluble compounds. Significantly, lower maternal blood concentrations than in maternal blubber biopsies suggest a stratification of POP concentrations in the blubber column of lactating female and lower concentrations in the metabolic active inner layers. Over the course of lactation, there was a significant increase in maternal blood and milk concentrations of POPs as opposed to no change in maternal blubber biopsy concentrations. This was most apparent for the hydrophobic and high-chlorinated compounds. The most likely explanation for this is that the metabolic active inner blubber layer, from which the milk lipids are derived from, is in steady state with the circulatory system, while the outer layers are more static and only slowly respond to changes in concentrations elsewhere in the body. The concentrations of the high-chlorinated and hydrophobic compounds were substantially lower in pup blubber than in maternal blubber. This probably relates the combined effect of these compounds stratification in maternal blubber and their slow transfer into the milk. The present study shows that the more hydrophobic and high-chlorinated compounds come to steady state less quickly in the different tissues than the more water-soluble and low-chlorinated compounds in the lactating female and her offspring. This has implications for which matrices to choose when sampling for assessing the toxicological risk of POPs in seals.

Adipose Tissue↗
PubMed1993

Biodegradation of chlorinated aliphatics and aromatic compounds in total-recycle expanded-bed biofilm reactors.

Ground-water contamination by chlorinated aliphatic compounds is a major cause for concern because of their toxicity. This study examined the biodegradation of trichloroethylene and aromatic compounds by microbial consortia enriched from contaminated subsurface sediments. The consortia were capable of utilizing methane and propane as sources of carbon and energy. Two continuously recycled expanded-bed bioreactors were inoculated with (1) the subsurface consortium, and (2) P. fluorescence, P. putida (strains pRB1401 and pWWO), and M. trichosporium OB3b. An uninoculated reactor containing 0.2% sodium azide and 0.5% formalin served as the control. Methane (5% v/v) and propane (3% v/v) were maintained by batch feeding through the course of the experiment. Greater than 97% degradation of trichloroethylene was observed over a period of 12 d. More than 99% of benzene, toluene, and xylene were degraded within the first 7 d. Dissolved oxygen levels were measured and found to be in the range 4.9-6.5 mg/L throughout the experiments.

Benzene↗
PubMed2005

Multi-residue screening of chlorinated and brominated compounds from aquaculture samples using matrix solid-phase dispersion--gas chromatography-mass spectrometry.

An effective multiresidual method for the trace analysis of fifteen compounds from a diverse group of pesticides, polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyl (PCBs) and polybrominated biphenyl (PBBs) in aquaculture feed is described. The analytical procedure is based on the matrix solid-phase dispersion (MSPD) of feed sample and subsequent elution with hexane. The MSPD process was evaluated using an asymmetrical experimental design 2(3)3(2)//9. Factors such as C18 sorbent amount, kind of adsorbents, solvent volume and elution mode were considered. The results suggest that the operational MSPD conditions are elution with pressure, 1 g of C18, basic alumina as adsorbent and 30 mL of hexane. The overall method including MSPD procedure and GC coupled to mass spectrometry (MS/MS) has been applied to several samples of aquaculture feed and marine species. Precision and accuracy of the analytical method were determined using the reference material from the International Atomic Energy Agency (IAEA-406), showing a good agreement to the referenced values.

Aquaculture↗
PubMed2004

Heterogeneous photocatalysis of aromatic and chlorinated volatile organic compounds (VOCs) for non-occupational indoor air application.

The current study evaluated the technical feasibility of applying TiO2 photocatalysis to the removal of low-ppb concentrations of volatile organic compounds (VOCs) commonly associated with non-occupational indoor air quality issues. A series of experiments was conducted to evaluate five parameters (relative humidity (RH), hydraulic diameter (HD), feeding type (FT) for VOCs, photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) in relation to the PCO destruction efficiencies of the selected target VOCs. None of the target VOCs exhibited any significant dependence on the RH, which is inconsistent with a previous study where, under conditions of low humidity and a ppm toluene inlet level, a drop in the PCO efficiency was reported with a decreasing humidity. However, the other four parameters (HD, RM, FT, and IPS) were found to be important for better VOC removal efficiencies as regards the application of TiO2 photocatalytic technology for cleansing non-occupational indoor air. The PCO destruction of VOCs at concentrations associated with non-occupational indoor air quality issues was up to nearly 100%, and the CO generated during PCO was a negligible addition to indoor CO levels. Accordingly, a PCO reactor would appear to be an important tool in the effort to improve non-occupational indoor air quality.

Air Pollutants↗
PubMed2003

Disinfection efficacy of organic chloramines.

The disinfection efficacies of model organic chloramines were investigated. Twenty amino acids and two nucleic acid bases were chlorinated separately with sodium hypochlorite at a Cl:N molar ratio of 0.4:1, and were then used to treat an E. coli suspension for 60 min. DPD/FAS titration was carried out to obtain the concentration of the chlorinated nitrogenous organic compounds as a function of time. In addition, membrane introduction mass spectrometry (MIMS) was used to quantify inorganic chloramines (mono-, di-, and trichloramine). The results of these experiments showed that the organic chloramines examined in this research had little or no effect on the viability of E. coli. MIMS analyses demonstrated that there was no quantifiable formation of inorganic chloramines when the organic nitrogen compounds were chlorinated.

Amino Acids↗
PubMed1980

Chemical structure and biodegradability of halogenated aromatic compounds. Conversion of chlorinated muconic acids into maleoylacetic acid.

1. An enzyme for the cycloisomerization of 2- and 3-chloro-cis,cis-muconic acid was isolated from 3-chlorobenzoate-grown cells of Pseudomonas sp. B13. It was named muconate cycloisomerase II, because it could it clearly be differentiated by its Km and Vmax. values from an ordinary muconate cycloisomerase, which functioned in benzoate catabolism and exhibited low activity with the chlorinated substrates. 2-Chloro-cis,cis-muconic acid was converted into trans- and 3-chloro-cis,cis--muconic acid into cis-4-carboxymethylenebut-2-en-4-olide together with dehalogenation. 2. An enzyme was isolated from chlorobenzoate-grown cells, which converted the 4-carboxymethylenebut-2-en-4-olides into maleoylacetic acid.

Biodegradation, Environmental↗
PubMedDate not supplied

[Formation of organochlorine compounds in the chlorination of water containing industrial contaminants: Experimental assessment and forecasting].

The hazard of GSS production from commercial chemicals was evaluated during water chlorination by analyzing the results of experimental study of chlorination of chemicals from different classes. Structural fragments were found, their presence in the molecule determined the capacity of a substance to undergo intensive transformation to form GSS. The regularities that associates the structure of a substance with the rate of chlorination were detected. Some theoretical approaches to the determination of the ability of chemical to chlorinate are outlined.

Hydrocarbons, Chlorinated↗
PubMedDate not supplied

[Antimicrobial activity exerted by sodium dichloroisocyanurate].

Sodium dichloroisocyanurate is a chlorinated cleaner. It was used for swimming pool sanitation and for the sterilisation of linen. Not recently ago sodium dichloroisocyanurate has substituted hypochlorite for the sterilisation of infant feeding bottles and teats. Sodium dichloroisocyanurate is soluble in water; this condition causes the hydrolysis of sodium dichloroisocyanurate in hypochlorous acid, that is the active agent, isocyanurate and isocyanurate chlorine. These compounds form a chlorine protein that carry out microbicidal activity. In a toxicology study has been shown that no severe changes in the normal metabolic function occurred, furthermore sodium dichloroisocyanurate has not shown teratogenic effects at the concentration of 200 mg/kg. The antimicrobial activity of sodium dichloroisocyanurate was evaluated against Gram negative bacteria such as E. coli or Salmonella typhimurium and against some fungi. This study illustrates a rapid antimicrobial activity using concentrations. Our study concentrated on the antimicrobial activity of sodium dichloroisocyanurate in some experimental conditions. We tested 66 strains of fungi, 28 Gram positive bacteria and 29 Gram negative bacteria. We also evaluated the antimicrobial activity of sodium dichloroisocyanurate against protozoa such as Trichomonas vaginalis. The antimicrobial activity was evaluated in cultural conditions and non cultural conditions; in these experiments we observed similar action in both the commercial product and pure substance. In cultural conditions sodium dichloroisocyanurate shows a good activity against fungi and bacteria, moreover it can be observed that the serum didn't interfere with its activity. In a non cultural condition the Candida was killed rapidly by the sodium dichloroisocyanurate but this activity is influenced by the growth phase of the yeast. Against mycelial form such as Penicillium and Aspergillus the sodium dichloroisocyanurate needs a longer contact time than yeast form for its activity. It is interesting to note that well known bacteria, that are resistant to the common antimicrobial agents, such as Pseudomonas aeruginosa, were inhibited by sodium dichloroisocyanurate in a rapid bactericidal action. Our data demonstrates that no significant adverse influence on the activity of sodium dichloroisocyanurate was shown by pH and by temperature even if in some experimental conditions increased activity was noticed at pH = 6.6. The sodium dichloroisocyanurate has demonstrated good activity against Trichomonas vaginalis. This fact extends the broad-spectrum activity of sodium dichloroisocyanurate to the protozoa. In conclusion, sodium dichloroisocyanurate has demonstrated a good activity against all tested strains, furthermore its activity did not decrease in the presence of 1% of organic substance (serum etc.).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗