Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bromine Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2001

Anthropogenic and natural organohalogen compounds in blubber of dolphins and dugongs (Dugong dugon) from northeastern Australia.

A range of organohalogen compounds (10 polychlorinated biphenyl [PCB] congeners, DDT and metabolites, chlordane-related compounds, the potential natural organochlorine compound Q1, toxaphene, hexachlorobenzene, hexachlorocyclohexanes, dieldrin, and several yet unidentified brominated compounds) were detected in the blubber of four bottlenose dolphins (Tursiops truncatus), one common dolphin (Delphinus delphis), and seven dugongs (Dugong dugon), as well as in adipose tissue of a green turtle (Chelonia mydas) and a python (Morelia spilota) from northeast Queensland (Australia). The green turtle and dugongs accumulated lower organohalogen levels than the dolphins. Lower levels in dugongs were expected because this species is exclusively herbivorous. Highest PCB and DDT levels recorded in dugongs were 209 and 173 microg/kg lipids, respectively. Levels of the nonanthropogenic heptachlorinated compound Q1 (highest level in dugongs was 160 microg/kg lipids) were estimated using the ECD response factor of trans-nonachlor. Highest organohalogen levels were found in blubber of dolphins for sumDDT (575--52,500 microg/kg) and PCBs (600--25,500 microg/kg lipids). Furthermore, Q1 was a major organohalogen detected in all samples analyzed, ranging from 450--9,100 microg/kg lipids. The highest concentration of Q1 determined in this study represents the highest concentration reported to date in an environmental sample. Levels of chlordane-related compounds were also high (280--7,700 microg/kg, mainly derived from trans-nonachlor), but concentrations of hexachlorobenzene, hexachlorocyclohexanes, dieldrin, and toxaphene were relatively low and contributed little to the overall organohalogen contamination. Furthermore, a series of three major (BC-1, BC-2, and BC-3) and six minor (BC-4 through BC-9) unknown brominated compounds were observable by extracting m/z 79 and m/z 81 from the GC/ECNI-MS full scan run. Structural proposals were made for the two major recalcitrant compounds (referred to as BC-1 and BC-2). BC-2 appears to be a tetrabromo-methoxy-diphenylether (512 u) and BC-1 has 14 u (corresponding with an additional CH(2) group) more relative to BC-1. In general, the organohalogen pattern observed in blubber of dolphins was different compared to similar samples from other locations in the world, which is apparent from the fact that the four major abundant signals in the GC/ECD chromatogram of D. delphis originated from the four unknown compounds Q1, BC-1, BC-2, and BC-3.

Adipose Tissue↗
PubMed2007

Physicochemical properties of selected polybrominated diphenyl ethers and extension of the UNIFAC model to brominated aromatic compounds.

The aqueous solubilities (S(w)) at various temperatures from 283 K to 308 K and 1-octanol/water partition coefficients (K(ow)) for four polybrominated diphenyl ethers (PBDEs: 4,4'-dibromodiphenyl ether (BDE-15), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153)) were measured by the generator column method. The S(w) and K(ow) data revealed the effect of bromine substitution and basic structure on S(w) and K(ow). To estimate the infinite dilution activity coefficients (gamma(i)(w,infinity)) of the PBDEs in water from the S(w) data, enthalpies of fusion and melting points for those compounds were measured with a differential scanning calorimeter. Henry's Law constants (H(w)) of the PBDEs were derived from the determined gamma(i)(w,infinity) and literature vapor pressure data. Some physicochemical characteristics of PBDEs were also suggested by comparing the present property data with that of polychlorinated dibenzo-p-dioxins, brominated phenols and brominated benzenes in past studies. Furthermore, in order to represent different phase equilibria including solubility and partition equilibrium for other brominated aromatic compounds using the UNIFAC model, a pair of UNIFAC group interaction parameters between the bromine and water group were determined from the S(w) and K(ow) data of PBDEs and brominated benzenes. The ability of the determined parameters to represent both properties of brominated aromatics was evaluated.

1-Octanol↗
PubMed2003

Environmental release and behavior of brominated flame retardants.

Recently, environmental problems relating to brominated flame retardants (BFRs) have become a matter of greater concern than ever before, because of the recent marked increase in levels of polybrominated diphenyl ethers (PBDEs) found in human milk in Sweden and North America. The question that arises is whether environmental levels of PBDEs and other BFRs will continue to increase, causing toxic effects to humans. In an attempt to elucidate the current state of the science of BFRs, we review the consumer demand for BFRs (mainly in Japan), the characteristics of waste flame-retarded products, sources of emission, environmental behavior, routes of exposure of humans, temporal trends, and thermal-breakdown products of BFRs. At present, flame-retarded consumer products manufactured 10-20 years ago, when PBDEs were frequently used, are being dumped. The possible major sources of emission of BFRs into the environment are effluent and flue gases from BFR factories and other facilities processing BFRs. With respect to the environmental behavior of BFRs, the lower brominated compounds are, on the whole, predicted to be more volatile, more water soluble, and more bioaccumulative than the higher brominated compounds. The most probable route for exposure of the general human population to PBDEs, especially the lower brominated congeners, is through the diet. The release of BFRs from consumer products treated with these compounds could also lead to human exposure. Temporal trends in PBDE levels in the environment and in humans worldwide seem to vary considerably, depending on the regions or country, with possible reflections of the historic and current use of PBDEs. The environment and the general human population are also exposed to the thermal-breakdown products of PBDEs, such as polybrominated and mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs and mixed PXDDs/DFs).

Environmental Exposure↗
PubMed2005

Determination of HBCD, PBDEs and MeO-BDEs in California sea lions (Zalophus californianus) stranded between 1993 and 2003.

Blubber samples from male California sea lions (Zalphophus californianus) stranded between 1993 and 2003 were analyzed for 27 polybrominated diphenyl ether (PBDE) congeners, three isomers of hexabromocyclododecane (HBCD) and 14 methoxylated polybrominated diphenyl ether (MeO-BDE) congeners. Total PBDEs ranged from 450 ng/g to 4740 ng/g wet mass and total HBCD ranged from < 0.3 ng/g to 12 ng/g wet mass. The concentration of HBCD increased from 0.7 ng/g to12.0 ng/g wet mass in sea lion blubber between 1993 and 2003. However, no significant temporal trend was observed for any of the other brominated compounds over this 10 year period. Only one of the 14 MeO-BDE congeners was detected in the blubber samples, 6-methoxy-2,2',4,4'-tetrabromodiphenyl ether (6-MeO-BDE 47), and concentrations ranged from < 0.2 ng/g to 12 ng/g wet mass. A bromo-, chloro-heterocyclic compound, 1,1'-dimethyl-tetrabromo-dichloro-2,2'-bipyrrole (DBP-Br4Cl2), previously reported in marine species along the Pacific coast, was also identified in the sea lion blubber. DBP-Br4Cl2 ranged from 44 ng/g wet mass to 660 ng/g wet mass and was present at concentrations rivaling the dominant PBDE congener, BDE 47 (2,2',4,4'-tetrabromodiphenyl ether). Concentrations of DBP-Br4Cl2 were positively correlated with 6-MeO-BDE 47 (r = 0.7; p < 0.05). Both of these compounds have been identified in marine algae and sponges, and studies suggest they are both produced from natural sources. This study demonstrates that brominated compounds from both anthropogenic and biogenic sources can accumulate to similar levels in marine mammals. In addition, HBCD concentrations appear to be increasing in California sea lion populations, whereas PBDE concentrations, between 1993 and 2003, were highly variable.

Adipose Tissue↗
PubMed2005

Halogenated natural products in five species of Antarctic sponges: compounds with POP-like properties?

Purified extracts of five species of Antarctic sponges (Demospongiae: Kirkpatrickia variolosa, Artemisina apollinis, Phorbas glaberrima, and Halichondria sp. and Calcarea: Leucetta antarctica) from King George Island were analyzed by GC/MS for the presence of persistent and lipophilic halogenated compounds to identify bioaccumulative halogenated natural products. Sample extracts were prepared using methods identical for the determination of POPs, namely, microwave-assisted extraction with organic solvents, gel permeation chromatography, and column chromatography on deactivated silica. In addition, samples were treated with sulfuric acid to remove acid-destructible compounds. PCBs were not detectable and only traces of lindane, p,p'-DDE, and alpha-HCH were detected in these samples in decreasing order of abundance, underscoring their uncontaminated state. In contrast, 146 brominated compounds were identified by correct isotopic ratios m/z 79 and 81, 50% of which eluted prior to lindane including the most abundant peaks. Each sponge sample contained > or = 35 brominated compounds of natural origin, 14 of which were detected in all species. Estimated concentrations ranged from the high ng/kg to mg/kg (air-dried weights) and relative distributions of the same compounds in different sponges were highly variable. The high abundance of these compounds relative to known anthropogenic pollutants strongly suggests a natural origin. Multiple mode (EI-, ECNI-, and PCI-) GC/MS enabled identification of an aliphatic ketone tentatively identified as 1,1,2-tribromo-oct-1-en-3-one, present in all species but highest in Phorbas glaberrima. Several halogenated phenols including 2,4,6-tribromophenol were also abundant in Phorbas glaberrima as were halogenated anisoles in lower relative abundances. The halogenated phenols were analyzed without derivatization. The sample of Halichondria sp. contained the dibromotrichloro monoterpene MHC-1, a recently described environmental contaminant in fish and seals. Retrospective analysis of other marine samples confirmed that 2,4,6-tribromophenol was present in seal blubber from both the Arctic and the Antarctic. The presence of naturally occurring organohalogens such as 2,4,6-tribromophenol and MHC-1 in Antarctic marine invertebrates thus provides a link to their occurrence in marine mammals.

Animals↗
PubMed2004

Probing the activity differences of simple and complex brominated aryl compounds against 15-soybean, 15-human, and 12-human lipoxygenase.

Lipoxygenases (LO) have been implicated in asthma, immune disorders, and various cancers. As a consequence of these broad biological implications, there is great interest in understanding the effects of naturally occurring and environmental contaminants against its activity. On the basis of our earlier studies indicating that polybrominated diphenol ethers are potent inhibitors to mammalian 15-LO, we expanded our structure-activity study to include marine-derived brominated phenol ethers (including a newly discovered tribrominated diphenyl ether), dioxins, and bastadins, as well as the synthetic brominated fire retardants, brominated bisphenol A (BBPA), and polybrominated diphenyl ethers (PBDEs). We report herein the effects of 21 simple and complex organobromine compounds against human platelet 12-LO, human reticulocyte 15-LO, and soybean 15-LO-1.

Animals↗
PubMed1996

[Toxicity of selected brominated aromatic compounds].

Flame retardants are added to plastic materials, textiles, wood, hydraulic liquids etc. for reducing their inflammability. These substances reduce the heat and carbon monoxide formation in case of fire. They are added in high amounts, even up to 30% of product mass (e.g. plastic material). The production of brominated flame retardants has been steadily rising in the last 20 years, e.g. in the 1990s the world production of polybromodiphenyl ethers (PBDE) reached 40,000 tons annually. Mainly polybrominated flame retardants are produced, e.g. polybromobiphenyls (PBB), PBDE, hexabromobenzene (HBB). Their toxicity is low or nil, the DL 50 values are over 1 g/kg. However, when administered in low doses over longer time periods they can cause changes leading to porphyria. The information on the toxicity of polybrominated flame retardants for humans is derived mainly from the accident in Michigan, where PBB contamination of fodder for farm animals occurred with consequent contamination of food. In consumers of contaminated food cutaneous changes and neurological and muscular symptoms were noted. Polybrominated flame retardants can be metabolized and undergo biodegradation mainly trough debromination. The data on the toxicity of debromination products point to di- and tribromobenzenes, some of which are highly hepatotoxic. In acute poisoning hepatocellular damage manifest itself as necrotic changes in experimental animals receiving 0.1-0.8 of DL 50 of di- or tribromobenzene. After repeated administration of lower doses the hepatocellular damage assumes the features of porphyrogenic injury. In the environment polybrominated flame retardants can be transformed by various factors (high temperature during fire accidents, incomplete incineration of waste) to polybrominated dibenzodioxins of dibenzofurans whose lethal doses can in extreme cases be 0.001 mg for 1 kg body weight.

Animals↗
PubMed2006

Modeling brominated trihalomethane compounds in drinking water at a treatment plant in Beaumont, Texas.

The premise of this study is that the presence of bromide has a substantial effect on both the speciation and total formation of trihalomethane (THM). Consequently, models of water containing substantial bromide concentrations require refinement because they are only calibrated with raw water with high humic acid content. This study investigates and reports efforts on such refinement. The objectives of work reported in this paper are to formulate and validate a new correlative model that is based on physical principles and incorporates high levels of bromide that affect THM formation using raw water rich in both humic and fulvic acid. Two types of THM precursors are considered in the model discussed in this paper: (1) activated aromatic groups, which are more reactive with chlorine than with bromine, and (2) aliphatic groups, which are more reactive with bromine than with chlorine. Aliphatic and aromatic carbons are incorporated in the model by the inclusion of pertinent variables such as C/N and Br/Cl2 in the algorithm. The model also includes NH4+. This variable affects chlorine consumption that, in turn, potentially affects THM formation. For the first time ever, organic carbon to organic nitrogen and bromide to chlorine ratios is also used as variables potentially affecting THM formation when treating drinking water. The THM model formulated in this paper is an empirical model based on scientific principles and not simply a regression equation. The formulated model is pronounced valid based on a validation effort that employs a portion of an EPA database that was not used for model formulation.

Bromides↗
PubMed1992

2-Bromopalmitoyl-CoA and 2-bromopalmitate: promiscuous inhibitors of membrane-bound enzymes.

2-Bromopalmitate and 2-bromopalmitoyl-CoA have been shown to inhibit a variety of enzymes and proteins associated with lipid metabolism. We found that both of the brominated compounds were non-competitive inhibitors of two microsomal activities of triacylglycerol biosynthesis, the mono- and diacylglycerol acyltransferases. With both compounds, the calculated Ki values were lower than the Km value for the palmitoyl-CoA substrate. In addition to inhibiting two other lipid synthetic activities, fatty acid CoA ligase and glycerol-3-P acyltransferase, 2-bromopalmitate and 2-bromopalmitoyl-CoA also inhibited two microsomal enzyme activities that are not related to lipid metabolism, NADPH cytochrome-c reductase and glucose-6-phosphatase. Inhibition of the three acyltransferases and fatty acid CoA ligase could be overcome by the addition of phospholipid vesicles, and 2-bromo[14C]palmitate readily labeled a large number of membrane-bound proteins as well as cytosolic proteins that had been solubilized in SDS. Thus, it appears likely that the inhibitory properties of the brominated compounds strongly depend on the effective concentration of the inhibitor within membranes rather than on any specific affinity for an acyl-chain binding region of the enzyme.

Acyltransferases↗
PubMed2006

Biotransformation of the flame retardant tetrabromo-bisphenol A by human and rat sub-cellular liver fractions.

The comparative in vitro metabolism of the flame retardant tetrabromo-bisphenol A was studied in rat and human using a [(14)C]-radio-labelled molecule. Tetrabromo-bisphenol A is metabolised into the corresponding glucuronide (liver S9 fractions) and several other metabolites produced by cytochrome P450 dependent pathways (liver microsomes and liver S9 fractions). No major qualitative differences were observed between rat and human, regardless of the selected concentration, within the 20-200 microM range. Tetrabromo-bisphenol A undergoes an oxidative cleavage near the central carbon of the molecule, that leads to the production of hydroxylated dibromo-phenol, hydroxylated dibromo-isopropyl-phenol and glutathione conjugated dibromo-isopropyl-phenol. The main metabolites of tetrabromo-bisphenol A are two molecules of lower polarity than the parent compound, characterised as a hexa-brominated compound with three aromatic rings and a hepta-brominated dimer-like compound, respectively. Both structures, as well as the lower molecular weight metabolites resulting from the breakdown of the molecule, suggest the occurrence of chemically reactive intermediates formed following a first step oxidation of tetrabromo-bisphenol A.

Animals↗