Search results for "Chlorin"
showing 10 items of 374 documents
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…
Effects of primary- and secondary-treated bleached kraft mill effluents on the immune system and physiological parameters of roach.
2000
The present study was designed to examine, whether, effluents from a modern pulp and paper mill using elemental chlorine-free/total chlorine-free (ECF/TCF) bleaching, exert effects on the immune system of fish and, in addition, to relate these findings to physiological parameters known to be affected by bleached kraft-mill effluents (BKME). Roach (Rutilus rutilus) were exposed in laboratory conditions to primary- or secondary-treated effluent from a pulp and paper mill. In order to study their capability to respond to foreign antigens they were immunised with bovine gamma-globulin (BGG) prior to exposure. The number of anti-BGG antibody-secreting cells (ASC) and the number of immunoglobulin…
Brominated flame retardants and organochlorines in the European environment using great tit eggs as a biomonitoring tool
2009
Large-scale studies are essential to assess the emission patterns and spatial distribution of organohalogenated pollutants (OHPs) in the environment. Bird eggs have several advantages compared to other environmental media which have previously been used to map the distribution of OHPs. In this study, large-scale geographical variation in the occurrence of OHPs, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), was investigated throughout Europe using eggs of a terrestrial residential passerine species, the great tit (Parus major). Great tit eggs from 22 sampling sites, involving urban, rural and remote areas, in 14 Europea…
Guanine 6-O-Methylation Pattern within the Dioxin Responsive Element of theCYP1A1 Enhancer Shows Two Critical Guanines for AhR/ARNT Binding
2006
The core-recognition motif for TCDD-liganded AhR/ARNT complex of the dioxin-responsive element (DRE) contains four guanine residues, three on the antisense (5'-T T / A GCGTG-3') and one on the sense (5'-CACGC A / T A-3') strand. It has been reported that, in methylation-protection and methylation-interference assays, the TCDD-liganded AhR/ARNT contacts all four guanine residues. On the other hand, it is known that some anticancer drugs, and various environmental and workplace chemicals, including strongly human carcinogenic nitrosoamines, lead to the highly miscoding 6-O-methylation of guanine. In the present study, we have investigated whether specific methylation of guanine at the 6-O-pos…
Electrochemical processes in macro and microfluidic cells for the abatement of chloroacetic acid from water
2014
Abstract The remediation of solutions contaminated with monochloroacetic acid (CAA), which is one of the most resistant haloacetic acids (HAAs) to chemical degradation, dramatically depends on the adopted electrochemical approach: (i) CAA is only poorly oxidized either by homogeneous hydroxyl radical in electro-Fenton (EF), electrogenerated active chlorine or electro-oxidation on Pt anode; (ii) it is moderately abated by direct reduction on silver or compact graphite cathodes (from 30% in macro cells to 60% in the microfluidic devices); (iii) it is quantitatively removed by direct electro-oxidation on a boron-doped diamond (BDD) anode. The use of a microreactor enables operation in the abse…
Characterization of Chlorolignins in Bleached Kraft Pulp Mill Effluents Using Elemental Analysis and Fingerprinting by CuO Oxidation And Hplc
1994
Abstract Elemental analyses and chemical degradation techniques were applied to characterize lignin compounds in different stages of the chlorine bleaching process and in total mill effluent. Ultrafiltration was used for separation of chlorolignins into three nominal molecular weight fractions. Alkaline CuO oxidation products were analyzed by HPLC with diode array detection. Major compounds were identified by reference to authentic compounds. For comparison, native lignins (MWL), kraft lignins, and humic substances were studied as well. The oxygen, carbon and organic chlorine contents were closely similar in the various mill samples and their fractions. In all mill samples, vanillin and 6-c…
Acute toxicity of some chlorinated phenolic compounds toSelenastrum capricornutum and phytoplankton
1985
Acute toxicity of several chlorinated phenolic compounds detected in waste waters of bleached pulp was determined forSelenastrum capricornutum and indigenous phytoplankton using bioassays. Five of the phenolic compounds were chlorocatechols, four were chloroguaiacols and one was chlorosyringol. The response ofSelenastrum capricornutum to chemicals was measured by cell counting and phytoplankton14C-uptake. Chlorinated catechols inhibited the growth ofSelenastrum cultures in lower concentrations than chlorinated guaiacols. The increasing number of chlorine substituents on the phenolic ring increased the toxicity of both chlorinated catechols and guaiacols. The EC50-values (0-96 hr) of the com…
Oxidation of melatonin by oxoferryl hemoglobin: A mechanistic study
2002
Reaction of melatonin with the hypervalent iron centre of oxoferryl hemoglobin, produced in aqueous solution from methemoglobin and H2O2, has been investigated at 37 degrees C and pH 7.4, by absorption spectroscopy. The reaction results in reduction of the oxoferryl moiety with formation of a heme-ferric containing hemoprotein. Stopped-flow spectrophotometric measurements provide evidence that the reduction of oxoferryl-Hb by melatonin is first-order in oxoferryl-Hb and first-order in melatonin. The bimolecular reaction constant at pH 7.4 and 37 degrees C is 112 +/- 1.0 M(-1) s(-1). Two major oxidation products from melatonin have been found by gas chromatography-mass spectroscopy: the cycl…
The solubilisation behaviour of some dichloroalkanes in aqueous solutions of PEO-PPO-PEO triblock copolymers: a dynamic light scattering, fluorescenc…
2006
The aggregation behaviour of PEO-PPO-PEO triblock copolymers in water and in water + chlorinated additive mixtures was studied by means of fluorescence spectroscopy, dynamic light scattering (DLS), and small-angle neutron scattering (SANS). The copolymers were chosen such as to investigate the effects of molecular architecture (L35 and 10R5) and molecular weight by keeping constant the hydrophilic/hydrophobic balance (F88 and F108). 1,2-Dichloroethane was used as a prototype of water basins contaminants. The hydrodynamic radius of the block copolymer aggregates (R(h,M)) and the intensity ratio of pyrene of the first and the third vibrational band (I(1)/I(3)) were determined as a function of…
Evaluation of the environmental impact of volcanic emissions from the chemistry of rainwater: Mount Etna area (Sicily)
2001
Abstract The S, halogen and NO 3 contents of rainwater samples from the Etnean area were studied in order to define the environmental impact of plume emissions on the local environment. Samples, collected on a network of 11 bulk rain gauges, show significant variability in anion content, which can be ascribed to different meteorological and environmental conditions at each sampling site and to a variable distance from the different source areas. Data analysis suggests that S, F, Cl and Br are mainly magma-derived, whereas NO 3 mainly originates from anthropogenic sources. Samples collected from sites close to craters display considerable temporal variability, with increased anion concentrat…