Collection and analysis of trace organic emissions from natural sources

Studies of adsorption of polychlorocarbons on carbon blacks by gas chromatography

Adsorption properties of carbon black before and after modification to polyhalogenohydrocarbons, including polyorganochlorine pesticides, have been investigated. It has been shown that graphitised thermal carbon blacks and carbochroms possess high adsorption capacity relative to the above compounds and can be used as supporting adsorbents to analyse these airborne chemicals. Modification raises the selectivity of adsorbents to the compounds being investigated and lowers retention volumes and heats of adsorption, which makes it possible to carry out thermal desorption of the accumulated species at lower temperatures.

Results of long-term experimental studies on the carcinogenicity of methyl alcohol and ethyl alcohol in rats

Methyl alcohol was administered in drinking water supplied ad libitum at doses of 20,000, 5,000, 500, or 0 ppm to groups of male and female Sprague-Dawley rats 8 weeks old at the start of the experiment. Animals were kept under observation until spontaneous death. Ethyl alcohol was administered by ingestion in drinking water at a concentration of 10% or 0% supplied ad libitum to groups of male and female Sprague-Dawley rats; breeders and offspring were included in the experiment. Treatment started at 39 weeks of age (breeders), 7 days before mating, or from embryo life (offspring) and lasted until their spontaneous death. Under tested experimental conditions, methyl alcohol and ethyl alcohol were demonstrated to be carcinogenic for various organs and tissues. They must also be considered multipotential carcinogenic agents. In addition to causing other tumors, ethyl alcohol induced malignant tumors of the oral cavity, tongue, and lips. These sites have been shown to be target organs in man by epidemiologic studies.

Wet effluent diffusion denuder technique and the determination of volatile organic compounds in air. II. Monoterpenes

The wet effluent diffusion denuder technique (WEDD), for the determination of alpha- and beta-pinenes, S-limonene, alpha-phellandrene, camphene and delta3-carene in air has been tested. These monoterpenes were continuously preconcentrated into a thin film of methanol (ethanol, 1-propanol and heptane) flowing down the inner wall of the cylindrical wet effluent diffusion denuder. The concentrates were analyzed by GC-FID and GC-MS, respectively.

A wind tunnel for measuring the gaseous losses of environmental chemicals from the soil/plant system under field-like conditions

Volatilization from treated areas is a major source of pesticide residues in air, fog, and rain. This may lead to long-range transport of pesticide residues to remote areas. Up to now most information on pesticide volatilization has come from laboratory experiments under controlled conditions. A new system has been designed and developed to measure the volatile losses of(14)C-labelled chemicals after application; the method compares with agricultural practice of treating soils or plants grown in lysimeters. Sensitive analytical methods guarantee a distinction between residues of unchanged pesticide, its metabolites or(14)CO2 as a mineralization product released into the air.

Thermal desorption-gas chromatography for the determination of benzene, aniline, nitrobenzene and chlorobenzene in workplace air

Sampling on Tenax TA of different mesh sizes followed by thermal desorption and gas chromatography was evaluated as a simple method for the determination of benzene, aniline, nitrobenzene and chlorobenzene in the workplace air. An alternative sampling technique in place of pump sampling was developed. Quantitative recoveries were obtained in the mass range 0.04-10 micrograms. It was found that air humidity had no effect on recovery. The charged tubes can be stored at room temperature for 5 days with no change in recovery. The particle size of Tenax TA has no significant effect on adsorption and desorption.

Determination of volatile sulphur compounds in air at the parts per trillion level by Tenax trapping and gas chromatography

A gas chromatographic technique is described for measuring various volatile sulphur compounds (H2S, COS, CS2, thiols, sulphides, disulphides) in air at the parts per trillion level. The sulphur compounds are trapped and concentrated at -196 degrees C in a small glass tube filled with the porous polymer Tenax GC. The excess of water in the air samples is pretrapped by calcium chloride, which drying agent does not adsorb any of the sulphur volatiles. The Tenax trap tube fits exactly in the injection port of the gas chromatograph, where the adsorbed sulphur compounds are liberated at 200 degrees C directly into the carrier gas stream and are transferred to the gas chromatographic column. The sulphur compounds are then assayed by means of a flame photometric detector. The Tenax trap tubes can be stored at -196 degrees C for more than 1 week without any loss of sulphur volatiles.

Volatiles of exogenous origin from the human oral cavity

The volatiles found in the headspace above male and female saliva were examined by combined gas chromatography--mass spectrometry. This had led to the identification of a number of constituents of exogenous origin. The most likely source of these products are atmospheric and water pollutants as well as food stuffs and cosmetic products. Volatiles from saliva represent a potential medium for the detection of reproductive states as well as local and systemic diseases. Consequently, knowledge of compounds not arising from the body's metabolic process if important to prevent their identification as anomalous metabolites.

Baseline studies of the global pollution. I. Occurrence of organohalogens in pristine European and antarctic aquatic environments

Pristine Alpian fresh water lakes with no run off were selected to monitor the atmospheric fall-out of C6--C12 -organochlorine compounds. Off-shore marine areas were taken for monitoring the average marine pollution by these compounds. In both cases fishes have been used as bioextractors. The analytical work-up combines solvent-partition, liquid chromatography and glass capillary gas chromatography with the electron capture detector. The idenfification is done by matching high-resilution retention indices of unknowns with those of reference compounds. The following compounds could be identified in the spawn of arctic chars (Salvelinus alpinus) caught in off-road Alpian lakes as well as in the liver of predatory antarctic cod (Dissostichus eleginoides) caught near South Georgia, as well as in Peru fish oil and crude sperm oil: hexachlorobenzene alpha-, beta-, gamma-hexachlorocyclohexane; 4,4'-DDT; 4,4'-DDE; 4,4'-DDD; 2,4'-DDE; 2,4'-DDD; heptachloroepoxide; polychlorobiphenyls (PCB) and polychlorocamphenes. Concentrations are given in nanogram/gram total lipid extract (ppb). First value Salvelinus (Alps), second value Dissostich (Antarctic Ocean), alpha-HCH: 40/0,1; beta-HCH: 4,1/0,1; gamma-HCH: 17,2/0,1; HCB: 65/8; 4,4'-DDT: 59/4; 4,4'-DDE: 477/5; sigma DDT 646/11,4; sigma PCB: 1030/32; sigma PCC: 124/68.

Study of water treatment effects on organic volatiles in drinking water

Volatile organics were determined during all stages of the water treatment process in a municipal water works. Analytical parameters for a quantitative procedure were investigated. The method used allows simultaneous determination of both halogenated and non-halogenated purgeable organics. Approximately 70 substances were identified by gas chromatography--mass spectrometry with capillary columns. Well water contained considerable quantities of aliphatic and aromatic substances. Halocarbons were formed during both steps of a double chlorination procedure, but the largest quantity was generated during the first step. Only tetrachloroethylene was present in untreated surface water in significant quantities. Most hydrocarbons were carried through the treatment process from the raw water to the finished water with little change in concentration.