Search results for "Chlorin"
showing 10 items of 374 documents
Unraveling metabolic flexibility of rhodococci in PCB transformation
2021
International audience; Even though the genetic attributes suggest presence of multiple degradation pathways, most of rhodococci are known to transform PCBs only via regular biphenyl (bph) pathway. Using GC-MS analysis, we monitored products formed during transformation of 2,4,4′-trichlorobiphenyl (PCB-28), 2,2′,5,5′-tetrachlorobiphenyl (PCB-52) and 2,4,3′-trichlorobiphenyl (PCB-25) by previously characterized PCB-degrading rhodococci Z6, T6, R2, and Z57, with the aim to explore their metabolic pleiotropy in PCB transformations. A striking number of different transformation products (TPs) carrying a phenyl ring as a substituent, both those generated as a part of the bph pathway and an array…
Comparative electrochemical treatments of two chlorinated aliphatic hydrocarbons. Time course of the main reaction by-products.
2011
The chlorinated aliphatic hydrocarbons conjugate toxicity with high chemical stability, bioaccumulation and long-range diffusivity. Chloroethanes are particularly ubiquitous in the industry and in household products, and their entry to the environment may entail potential risks for the living beings. At present, the US Environmental Protection Agency is carrying out the Endocrine Disruptor Screening Program (EDSP), where 1,2-dichloroethane (DCA) and 1,1,2,2-tetrachloroethane (TCA) are considered as priorities for their potential effects on the endocrine system. DCA is also found in the list of priority substances drawn up by the European Commission. To avoid the release of chloroethanes int…
Chloroterpenes and other organochlorines in Baltic, Finnish and Arctic wildlife
1991
Abstract Chloroterpene mixtures were analyzed as toxaphene (TOX) in Baltic, Finnish and Arctic fish, seal and bird samples together with DDT residues, hexachlorocyclohexanes (HCH), hexachlorobenzene (HCBz), chlordanes, hexachloronaphthalenes (HxCN), PCBs, PCDDs and PCDFs. TOX was found to be the most globally (evenly) distributed organochlorine compound in Scandinavia, thus far. TOX seemed to bioaccumulate significantly in fish but not in predatory birds in Finland.
The M74 syndrome of baltic salmon (Salmo salar) and organochlorine concentrations in the muscle of female salmon
1997
Abstract Organochlorine concentrations in the muscle of female Baltic salmon (Salmo salar), ascending for spawning in the Simojoki River on the north-eastern coast of the Gulf of Bothnia from 1988 to 1992 are given in this paper in relation to reproduction success, monitored as viability of offspring. In spring 1992 and 1993 all the yolk-sac fry of 52 % and 75 % of the females, sampled in autumns 1991 and 1992 respectively, died due to the M74 syndrome, i.e., heavy mortality of yolk-sac fry (YSM). The TEOs of the most frequently detected polychlorinated dibenzofurans (PCDFs: 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF and 2,3,7,8-TeCDF) and those of coplanar PCBs (CB77, CB126 and CB169) were about twi…
PCDEs, PCBs, PCDDs AND PCDFs in black guillemots and white-tailed sea eagles from the Baltic Sea
1995
Abstract Concentrations and patterns of several chloro compounds including polychlorinated dibenzo p-dioxins (PCDD), dibenzofurans (PCDF), biphenyls (PCB) and diphenyl ethers (PCDE) were determined in black guillemots ( Cepphus grylle L.) and white-tailed sea-eagles ( Hallaeetus albicilla L.) from the Baltic Sea environment. Three breast muscles of eagles were analyzed and had different concentrations and patterns of the studied compounds, whereas the three guillemot eggs were found to have more similar levels and patterns. The concentrations of individual PCDE congeners varied from
Swimming pool water--fractionation and genotoxicological characterization of organic constituents.
2005
Swimming pool water treatment in general includes flocculation, sand filtration, and subsequent disinfection with chlorine. The continuous chlorination and input of organic material by bathers in combination with recirculation of the pool water leads to an accumulation of disinfection by-products (DBPs) in the water. Several DBPs have been identified as human carcinogens and are thought to cause allergic asthma. Therefore, the elimination of DBPs is one major aim of pool water treatment. Using membrane filtration as an alternative treatment technology, DBPs can be removed more efficiently than with conventional treatment. In this study membrane filtration and genotoxicity testing were appli…
Biochemical stress response in tetradifon exposed Daphnia magna and its relationship to individual growth and reproduction
2009
Abstract Environmental risk assessment of chemicals toxicity requires the use of costly and labor-intensive chronic data and short-term tests provide additional information. Energy budget is used by the animals for their growth, reproduction, and metabolism and it is reduced in case of toxic stress. Tetradifon acaricide is frequently used in the European Mediterranean region and it is implicated in aquatic environmental pollution. Previous studies showed that the EC50-24 h of tetradifon on Daphnia magna was 8.92 mg/L. Based on that, D. magna were exposed to sublethal tetradifon concentrations of 0.10, 0.18, 0.22 and 0.44 mg/L for five days in order to investigate their effect on intermediat…
Chlorination of p-cymene by chlorine in carbon tetrachloride: Model compounds for environmental analyses
1989
p-Cymene was chlorinated by chlorine in CCl4. The products of the chlorination were separated by distillation and purified by preparative gas chromatography. The structures of chlorocompounds were confirmed by means of their NMR and mass spectra. The distillation gave as the main compounds: (2) 2-chloro-, (4) 2,3-dichloro-, (5) 2,5-dichloro-, (6) 2,3,6-trichloro-, (7) 2,3,5,6-tetrachloro-p-cymenes and as by-products: (8) 2,5,7-trichloro-p-cymene, (9) 2,6-dichloro-1-methyl-4-(1-methylethenyl)benzene (cymenene), and (10) 2,3,6-trichloro-1-methyl-4-(1-methylethenyl)benzene (cymenene).
Conformational polymorphs of 1,1,2,2-tetrachloroethane: pressure vs. temperature.
2011
Directional Cl···Cl type I and II interactions govern the low-density aggregation of 1,1,2,2-tetrachloroethane molecules in synclinal conformation in the crystalline state at low temperature, whereas the dense molecular packing in high-pressure is achieved for the antiperiplanar conformers and electrostatically less favored Cl···Cl contacts. The mechanism of transformation between loose and dense associations involves the collapse of Cl···Cl contacts and conformational conversion.
2-(N,N-Diethylaminomethyl)-6,7-trihydroquinolinyl-8-ylideneamine-Ni(ii) chlorides: application in ethylene dimerization and trimerization
2020
A series of Ni(II) complexes with the general formula [2-((NEt2)Me)-8-{N(Ar)}C9H8N]NiCl2, where Ar = 2,6-Me2C6H3 in Ni1, 2,6-Et2C6H3 in Ni2, 2,6-i-Pr2C6H3 in Ni3, 2,4,6-Me3C6H2 in Ni4, 2,6-Et2-4-MeC6H2 in Ni5, and 2,4,6-t-Bu3C6H2 in Ni6, has been prepared using a one-pot reaction of 2-(N,N-diethylaminomethyl)-6,7-dihydroquinolin-8(5H)-one with the corresponding aniline and nickel dichloride hexahydrate. The resultant complexes were characterized using elemental analysis and FT-IR spectroscopy, while the mononuclear Ni1 and Ni3 were also the subject of single-crystal X-ray diffraction study. On activation with MMAO, the complexes Ni1–Ni6 displayed good activity in ethylene oligomerization, f…