Linked Life Data

17950414

Source:http://linkedlifedata.com/resource/pubmed/id/17950414

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2008-3-3
pubmed:abstractText
The rates of hydrolysis reported for tetrachloroethylene (PCE) and trichloroethylene (TCE) at elevated temperatures range over two orders-of-magnitude, where some of the variability may be due to the presence of a gas phase. Recent studies suggest that volatile organic analysis (VOA) vials provide a low-cost and readily available zero headspace system for measuring aqueous-phase hydrolysis rates. This work involved measuring rates of PCE and TCE disappearance and the corresponding appearance of dechlorination products in water-filled VOA vials and flame-sealed ampules incubated at 21 and 55 degrees C for up to 95.5 days. While PCE and TCE concentrations readily decreased in the VOA vials to yield first-order half lives of 11.2 days for PCE and 21.1 days for TCE at 55 degrees C, concentrations of anticipated dechlorination products, including chloride, remained constant or were not detected. The rate of PCE disappearance was 34 times faster in VOA vials at 55 degrees C compared to values obtained with flame-sealed ampules containing PCE-contaminated water. In addition, the concentration of TCE increased slightly in flame-sealed ampules incubated at 55 degrees C, while a decrease in TCE levels was observed in the VOA vials. The observed losses of PCE and TCE in the VOA vials were attributed to diffusion and sorption in the septa, rather than to dechlorination. These findings demonstrate that VOA vials are not suitable for measuring rates of volatile organic compound hydrolysis at elevated temperatures.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0045-6535
pubmed:author
pubmed:issnType
Print
pubmed:volume
70
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2060-7
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Comparison of PCE and TCE disappearance in heated volatile organic analysis vials and flame-sealed ampules.
pubmed:affiliation
School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Dr., NW, Atlanta, GA 30332, United States. jed.costanza@gatech.edu
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't, Evaluation Studies