Commercial Mixtures (commercial + mixture)

Distribution by Scientific Domains


Selected Abstracts


Bioavailability of decabromodiphenyl ether to the marine polychaete Nereis virens

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2010
Susan L. Klosterhaus
Abstract The flame retardant decabromodiphenyl ether (BDE 209) accumulates in humans and terrestrial food webs, but few studies have reported the accumulation of BDE 209 in aquatic biota. To investigate the mechanisms controlling the bioavailability of BDE 209, a 28-d bioaccumulation experiment was conducted in which the marine polychaete worm Nereis virens was exposed to a decabromodiphenyl ether (deca-BDE) commercial mixture (>85% BDE 209) in spiked sediments, in spiked food, or in field sediments. Bioaccumulation from spiked substrate with maximum bioavailability demonstrated that BDE 209 accumulates in this species. Bioavailability depends on the exposure conditions, however, because BDE 209 in field sediments did not accumulate (<0.3 ng/g wet weight; 28-d biota-sediment accumulation factors [BSAFs] <0.001). When exposed to deca-BDE in spiked sediments also containing lower brominated congeners (a penta-BDE mixture), bioaccumulation of BDE 209 was 30 times lower than when exposed to deca-BDE alone. Selective accumulation of the lower brominated congeners supports their prevalence in higher trophic level species. The mechanisms responsible for limited accumulation of BDE 209 may involve characteristics of the sediment matrix and low transfer efficiency in the digestive fluid. Environ. Toxicol. Chem. 2010;29:860,868. © 2009 SETAC [source]


Dietary accumulation of hexabromocyclododecane diastereoisomers in juvenile rainbow trout (Oncorhynchus mykiss) I: Bioaccumulation parameters and evidence of bioisomerization

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006
Kerri Law
Abstract Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three diastereoisomers (,, ,, ,) of hexabromocyclododecane (C12H18Br6) via their diet for 56 d followed by 112 d of untreated food to examine bioaccumulation parameters and test the hypothesis of in vivo bioisomerization. Four groups of 70 fish were used in the study. Three groups were exposed to food fortified with known concentrations of an individual diastereoisomer, while a fourth group were fed unfortified food. Bioaccumulation of the ,-diastereoisomer was linear during the uptake phase, while the ,- and ,-diastereoisomers were found to increase exponentially with respective doubling times of 8.2 and 17.1 d. Both the ,- and the ,-diastereoisomers followed a first-order depuration kinetics with calculated half-lives of 157 ± 71 and 144 ± 60 d (±1 × standard error), respectively. The biomagnification factor (BMF) for the ,-diastereoisomer (BMF = 9.2) was two times greater than the ,-diastereoisomer (BMF = 4.3); the large BMF for the ,-diastereoisomer is consistent with this diastereoisomer dominating higher-trophic-level organisms. Although the BMF of the ,-diastereoisomer suggests that it will biomagnify, it is rarely detected in environmental samples because it is present in small quantities in commercial mixtures. Results from these studies also provide evidence of bioisomerization of the ,- and ,-diastereoisomers. Most importantly, the ,-diastereoisomer that was recalcitrant to bioisomerization by juvenile rainbow trout in this study and known to be the dominant diastereosiomer in fish was bioformed from both the ,- and the ,-diastereoisomers. To our knowledge, this is the first report of bioisomerization of a halogenated organic pollutant in biota. [source]


CHEMICAL PROPERTIES of PROCESSED RAS CHEESE SPREADS AS AFFECTED BY EMULSIFYING SALT MIXTURES,

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2000
LAILA B. ABDEL-HAMID
Processed cheese spreads were produced using Ras cheese and various emulsifying salt mixtures. Acidified Ras cheese (2 month old) was used as the cheese base with salt mixtures (1) Na-pyrophosphate + Na-polyphosphate, (2) Na-pyrophosphate + Na-polyphosphate + Na-tripolyphosphate, and (3) Na-pyrophosphate + Na-polyphosphate + Na-orthophosphate + Na-tripolyphosphate. For comparison, cheese spreads were also made with commercial emulsifying salts JOHA S10, S9 special, and NO. Total and soluble nitrogen (SN), peptization, ash, mineral, pH value, and potentiometric acid-base titration for the processed cheese were studied. Ash, sodium and potassium contents showed a significant difference among the treatments. the pH values tended to decrease with increasing polyphosphate ratio in the salt mixture and with prolonging the storage period. the SN increased with increasing the pyrophosphate percent in the salt mixture and with higher pH value. the buffering capacity of cheese made of salt mixtures difsered from those made of the commercial mixtures, and it was correlated to the individual salts used in the mixture. The mixtures of (1) 70+30%, (2) 60+30+10% and (3) 50+20+20+10% can be recommended for producing the spreadable processed Ras cheese with acceptable chemical properties. [source]


Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

MASS SPECTROMETRY REVIEWS, Issue 5 2010
Dongli Wang
Abstract This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br1-9BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:737,775, 2010 [source]