International programme on chemical safety

Guidelines for Canadian Drinking Water Quality

and psychophysical measurements reveal effects of acute low-level organic solvent exposure in humans. Int Arch Occup Environ Health 62:493-499. outcome of chronic low-level tetrachloroethene exposure measured in neighborhoods of dry cleaning shops.

Documentation of the Threshold Limit Values and Biological Exposure Indices

Several 1- and 2-carbon halogenated aliphatic organic compounds present at low concentrations (less than 100 micrograms/liter) were degraded under methanogenic conditions in batch bacterial cultures and in a continuous-flow methanogenic fixed-film laboratory-scale column. Greater than 90% degradation was observed within a 2-day detention time under continuous-flow methanogenic conditions with acetate as a primary substrate. Carbon-14 measurements indicated that chloroform, carbon tetrachloride, and 1,2-dichloroethane were almost completely oxidized to carbon dioxide, confirming removal by biooxidation. The initial step in the transformations of tetrachloroethylene and 1,1,2,2-tetrachloroethane to nonchlorinated end products appeared to be reductive dechlorination to trichloroethylene and 1,1,2-trichloroethane, respectively. Transformations of the brominated aliphatic compounds appear to be the result of both biological and chemical processes. The data suggest that transformations of halogenated aliphatic compounds can occur under methanogenic conditions in the environment.

Transformations of 1- and 2-carbon halogenated aliphatic organic compounds under methanogenic conditions.

L'absorbance UV a 254 nm est un excellent parametre pour evaluer les concentrations de carbone organique non purgeable et de precurseurs de trihalomethanes

Surrogate parameters for monitoring organic matter and thm precursors

Volatile Organic Compounds in Water at Thirty Canadian Potable Water Treatment Facilities

A comparison of dynamic and static head space and solvent extraction techniques for the determination of trihalomethanes in water

Comparison of trihalomethane levels and other water quality parameters for three treatment plants on the Ottawa River.

The sampling, storage, and shipping conditions used in this study were found to have little effect on the TOC levels in tap and river water samples. Therefore, samples from distant water supplies can readily be shipped to a central laboratory for reliable TOC determination (RSD<5%), if care is taken in bottle preparation and in sampling, and if the described procedures are followed. However, the procedures for sampling, storage and/or shipping of water samples with low TOC content cannot be recommended, due to contamination of the samples.

Effects of sampling, shipping, and storage on total organic carbon levels in water samples

The NIOSH charcoal tube method and a glass bulb grab sampling method were used to determine dichloromethane levels in the air of a room used for testing six paint removers. Dichloromethane and methanol were major components of five brush-on paint removers and an aerosol spray remover contained dichloromethane, toluene, and propane as major constituents. The grab sampling method, which showed sampling efficiency of 95%, precision of better than ±5%, and a detection limit of 0.01 g/m3, was useful in determining time profiles for dichloromethane levels in air. Since home environment standards have not been established, grab sampling results and TWA (1 and 8 hr) values obtained by the NIOSH method were compared with the occupational exposure limits recommended by NIOSH and ACGIH. In a room with poor ventilation, the recommended occupational health limits can easily be exceeded, even with use of small quantities of paint remover.

Peter D. Bothwell

Papers

Volatile Organic Compounds in Water at Thirty Canadian Potable Water Treatment Facilities

A comparison of dynamic and static head space and solvent extraction techniques for the determination of trihalomethanes in water

Comparison of trihalomethane levels and other water quality parameters for three treatment plants on the Ottawa River.

Effects of sampling, shipping, and storage on total organic carbon levels in water samples

Dichloromethane levels in air after application of paint removers