Distribution of volatile organic contaminants between water and air

1998 ◽  
Vol 25 (6) ◽  
pp. 1091-1095
Author(s):  
Jian Peng
Keyword(s):  
Sodium Chloride ◽  
Organic Contaminants ◽  
Equilibrium Distribution ◽  
Effect Of Temperature ◽  
Salting Out ◽  
Air Water Interface ◽  
Volatile Organic ◽  
Volatile Organic Contaminants ◽  
Benzene Toluene ◽  
The University

Exchange of synthetic organic contaminants across the air-water interface is a significant process affecting the fate of the contaminants released into the environment. Benzene, toluene, trichloroethylene, and tetrachloroethylene were selected as typical contaminants in this study. The equilibrium distribution of the selected volatile organic compounds between air and water was simulated in the laboratory at the University of Saskatchewan. A gas chromatograph headspace auto sampler system was used to analyze the chemical concentrations. The effect of salinity on the equilibrium distribution of selected organic contaminants between water and air was studied. Concentrations of sodium chloride from 100 to 1000 mol/m3 were used to simulate various levels of salinity in water at a temperature of 20°C. Typical seawater was simulated with 3.5% sodium chloride and tested at temperatures from 15°C to 45°C. A modified van't Hoff expression was developed by incorporating a salting-out coefficient to predict the effect of temperature and salinity on the equilibrium distribution. The parameters of the modified van't Hoff model were determined by using the experimental results for selected organic contaminants.Key words: water pollution, volatile organic contaminants, distribution, salinity.

The Distribution of Volatile Organics in a Leachate Plume, Gloucester, Ontario

1987 ◽  
Vol 22 (1) ◽  
pp. 49-64 ◽  
Author(s):  
J.F. Devlin ◽  
W.A. Gorman
Keyword(s):  
Organic Contaminants ◽  
Source Area ◽  
Unconfined Aquifer ◽  
High Concentration ◽  
Organic Contamination ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Volatile Organic ◽  
Volatile Organic Contaminants ◽  
Aquifer Sediments

Abstract The Gloucester Landfill is located near Ottawa, Ontario, on a northeast trending ridge of Quaternary age. The ridge comprises outwash sediments which make up two aquifer systems. A confined system exists next to bedrock, and is overlain by a silty-clayey stratum (the confining layer) which is, in turn, overlain by an unconfined aquifer system. Two independent volatile organic plumes have previously been identified at the landfill: the southeast plume, which has penetrated the confined aquifer system, and the northeast plume which is migrating in the unconfined aquifer. The distribution of volatile organic contaminants at the northeast plume site appears to be a function of two factors: (1) heterogeneities in the aquifer sediments are causing the channeling of contaminants through a narrow path; (2) the low fraction of organic carbon in the unconfined aquifer sediments at the northeast site is resulting in little retardation of the contaminants there, relative to those at the southeast site. Acetate was the only volatile fatty acid detected in the leachate. It was measurable only in areas where the volatile organic contamination was significant. Although methane was detected in the contaminated sediments, suggesting that microbial activity was present, the high concentration of acetate (>1000 ppm) which was detected down-gradient from the source area indicates that any biodegradation which is occurring is proceeding at a very slow rate.

scholarly journals 13C/12C Analysis of Ultra-Trace Amounts of Volatile Organic Contaminants in Groundwater by Vacuum Extraction

2010 ◽  
Vol 44 (3) ◽  
pp. 1023-1029 ◽  
Author(s):  
Helena I. F. Amaral ◽  
Michael Berg ◽  
Matthias S. Brennwald ◽  
Markus Hofer ◽  
Rolf Kipfer
Keyword(s):  
Organic Contaminants ◽  
Vacuum Extraction ◽  
Volatile Organic ◽  
Volatile Organic Contaminants ◽  
Ultra Trace

Determination of Volatile Organic Contaminants in Bulk Oils (Edible, Injectable, and Other Internal Medicinal) by Purge-and-Trap Gas Chromatography/Mass Spectrometry

1994 ◽  
Vol 77 (3) ◽  
pp. 647-654 ◽  
Author(s):  
Don W Thompson
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Vegetable Oils ◽  
Organic Contaminants ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Purge And Trap ◽  
Standard Curve ◽  
Volatile Organic ◽  
Volatile Organic Contaminants

Abstract Purge-and-trap gas chromatography/mass spectrometry is evaluated for the quantitation of part-per-billion levels of volatile organic contaminants in bulk vegetable oils. Results using 2 purge techniques (direct purging of the heated oil and purging after dispersing the oil on an aluminum oxide powder) and 2 quantitative methods (standard curve and deuterium-labeled internal standard addition) are reported. Twenty volatile compounds and 8 vegetable oils were investigated. Recovery data and estimated detection limits for each compound are reported for each purge technique. Generally acceptable recoveries (70-130% for more than 90% of the analyte spikes) and acceptable detection levels (approximately 4-10 ppb) were obtained for all compounds using either the external standard curve or the deuterium-isotope-labeled internal standard. The use of a dispersant (such as alumina) for sample purging resulted in poor recoveries of the highly volatile contaminants.

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