Search results for "benzofurans"
showing 10 items of 65 documents
Sphingobium aromaticiconvertens sp. nov., a xenobiotic-compound-degrading bacterium from polluted river sediment.
2007
A bacterial strain capable of degrading some monochlorinated dibenzofurans, designated RW16T, was isolated from aerobic River Elbe sediments. The strain was characterized based on 16S rRNA gene sequence analysis, DNA G+C content, physiological characteristics, polyamines, ubiquinone and polar lipid pattern and fatty acid composition. This analysis revealed that strain RW16T represents a novel species of the genus Sphingobium. The DNA G+C content of strain RW16T, 60.7 mol%, is the lowest yet reported for the genus. 16S rRNA gene sequence analysis placed strain RW16T as an outlier in the genus Sphingobium. The name Sphingobium aromaticiconvertens sp. nov. is proposed for this dibenzofuran-min…
2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in extracts of Baltic white-tailed sea eagles
1997
Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin-(TCDD) equivalents were measured in extracts of Baltic white-tailed sea eagle tissues. Extracts of salmon, ringed seal, and grey seal were analyzed as other predatory species of the same area. Concentrations in eagle and seal tissues were greater than those in salmon. Concentrations of TCDD equivalents (TCDD-EQs) determined by the H4IIE bioassay were compared with toxic equivalents (TEQs) derived from instrumental chemical analyses in fractions containing polychlorinated dibenzo-P-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) or coplanar polychlorinated biphenyls (PCBs). Toxic equivalents were calculated by use of an additive mod…
Polychlorinated organic compounds in the Arctic cod liver: trends and profiles
2000
Polychlorinated organic compounds (POCs) have been measured in Arctic cod liver from Vestertana Fjord for a period of 1987-1998. Significant decrease was observed for DDD (p = 0.043), alpha-HCH (p = 0.001), and gamma-HCH (lindane; p = 0.001). Contents of DDE, 2,3,7,8-tetrachlorodibenzofuran, PCBs, chlordanes, chloronaphthalenes, hexachlorobenzene and polychlorodiphenyl ethers had no significant trend. Contents of three hexa- and two heptachlorodibenzofurans and octachlorodibenzofuran increased slightly from 1987 to 1994, but then at very high rate from 1994 to 1998. Trends of HCHs, profiles of PCBs and levels of chlordanes are in accordance with atmospheric long range transport. The hexa-, …
Uptake rates of semipermeable membrane devices (SPMDs) for PCDDs, PCDFs and PCBs in water and sediment.
2000
Uptake rates of several PCDDs, PCDFs and PCBs were measured for semipermeable membrane devices (SPMDs) under controlled conditions in bulk water and sediment. The study was performed at 19 degrees C and 11 degrees C, and water and sediment concentrations were measured during the exposure. Linear uptake rates for specific PCDD/Fs and PCBs in 19 degrees C water varied from 34 to 111 l/m2 day and in 11 degrees C water from 8.8 to 96 l/m2 day for the whole SPMD. Uptake rates at 19 degrees C sediment ranged from 9.0 to 80 mgOC/m2 day and in 11 degrees C sediment, from 3.0 to 31, mgOC/m2 day. Partitioning of the compounds between membrane and lipid was also measured during the linear uptake phase…
Degradation half-life times of PCDDs, PCDFs and PCBs for environmental fate modeling.
2000
Literature search of the knowledge on the degradation of persistent organic pollutants (POPs) in environmental compartments air, water, soil and sediment was done in purpose to find properties of POPs of interest for modeling. One degradation process, hydrolysis (chemical degradation), was omitted as negligibly slow for POPs studied. The other two, photolysis and biodegradation processes, were considered separately in purpose to develop estimation procedures. The estimates can be given as pseudo first-order rate constants kP for photolysis and kB for biodegradation. For each compartment, an overall degradation rate is k(tot) = kP + kB and lifetime t(1/2) = ln 2/k(tot). The latter values, li…
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…
Urea as a PCDD/F inhibitor in municipal waste incineration.
2001
Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from municipal waste incineration have been widely studied because of their extensive toxicity, and many efforts have been made to restrict their emissions. Although a number of chemical compounds have been shown in laboratory-scale tests to inhibit the formation of PCDD/Fs, few have been tested in pilot- or full-scale plants. This work evaluates the effect of urea as a PCDD/F inhibitor in a pilot-scale incinerator that uses refuse-derived fuel (RDF). The decomposition of urea under the test conditions was also studied using detailed kinetic modeling. An aqueous solution of urea was injected into the flue gas stream …
SIMILARITIES IN BIOACCUMULATION PATTERNS OF POLYCHLORINATED DIBENZO-p-DIOXINS AND FURANS AND POLYCHLORINATED DIPHENYL ETHERS IN LABORATORY-EXPOSED OL…
2003
Sediment and chironomid samples were collected from a river in the vicinity of and downstream from a closed chlorophenol production plant, and they were analyzed for polychlorinated dibenzo-p-dioxins and furans (PCDD/F) and polychlorinated diphenyl ethers (PCDE). Bioaccumulation of these compounds from the sediments by the oligochaeta, Lumbriculus variegatus, and semipermeable membrane devices (SPMDs) was studied in a 28-d bioaccumulation test. The sum concentrations of PCDD/Fs and PCDEs in sediments varied spatially, peaking at the site below the production plant, but the congener composition remained fairly constant throughout the river. The sum concentrations of chironomids, oligochaetes…
Synthesis of iodobiaryls and dibenzofurans by direct coupling at BDD anodes.
2014
The first direct oxidative phenol-arene cross-coupling reactions of an iodine-containing guaiacol derivative and the possible over-oxidation products of electron-rich phenols are described. Hereby, a "green" and targeted synthesis for dibenzofurans was developed.
Reproductive effects in German cockroaches by ecdysteroid agonist RH-0345, juvenile hormone analogue methoprene and carbamate benfuracarb
2004
1379-1176 (Print) Journal Article Research Support, Non-U.S. Gov't; Blatta germanica is the more prevalent cockroach species in Algeria. In the present study, we tested the effect on reproduction in B. germanica of two insect growth regulators, RH-0345, a benzoylhydrazine analogue that mimics the action of 20-hydroxyecdysone, and methoprene, one of the most commercially important juvenile hormone analogues, and a novel carbamate insecticide, benfuracarb. The compounds were applied topically (10 and 20 microg/insect for RH-0345, and 1 and 10 microg/insect for methoprene) or orally administrated (at 2% for benfuracarb) on newly emerged females and evaluated on reproductive events during the a…