Frank M. Benoit

Disinfection by-products in Canadian drinking water

Abstract Halogenated disinfection by-products were determined in Canadian drinking water supplies where chlorine was used at some stage in the treatment process. The effects of applied disinfectants (chlorine, chloramine and ozone), seasonal variation (winter and summer) and spatial variation (treatment plant and distribution system) were examined. Chloroform, dichloroacetic acid and trichloroacetic acid were the major disinfection by-products found in all treated water samples and total haloacetic acid concentrations often equalled or exceeded total trihalomethane concentrations. Haloacetonitriles, halopropanones, chloral hydrate and chloropicrin were usually detected in treated water samples but at lower concentrations.

A one-year survey of halogenated disinfection by-products in the distribution system of treatment plants using three different disinfection processes

On a monthly basis, over a one year period, disinfection by-products (DBPs) were measured in raw water and in treated water at four locations in the distribution system of three water treatment plants that applied different treatment processes. DBP levels fluctuated as a function of water treatment practice (and variations therein) and the age and temperature of the water. Trihalomethane levels were higher in the summer than in the winter and increased in the distribution system with increasing distance from the plant. Levels of haloacetic acids and other DBPs were usually higher in summer than in winter but their levels did not increase consistently within the distribution system. After an initial increase, levels of dichloro- and trichloroacetic acids often decreased within the distribution system. No single sampling event captured the complete image of the behaviour of DBPs in drinking water. The authors recommend that in-depth studies be carried out to develop sampling strategies for DBPs.

A pilot study on the determination of perfluorooctanesulfonate and other perfluorinated compounds in blood of Canadians

A pilot study was conducted to provide preliminary data on the concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorooctanesulfonamide (PFOSA) in the blood of Canadians. A set of 56 human serum samples was collected from non-occupationally exposed Canadians and analyzed by microbore HPLC-negative ion electrospray tandem mass spectrometry. PFOS was the main component of perfluorinated organic compounds (PFCs) and was detected in all 56 blood specimens at an average concentration of 28.8 ng mL(-1) and a range from 3.7 to 65.1 ng mL(-1). The concentration of PFOA was an order of magnitude lower than that of PFOS and was found only in 16 samples (29%) at concentrations above the limit of quantification (LOQ). PFOSA was not detected at levels above the method detection limit (MDL) in any of the samples. The levels of PFCs observed in the sample group of non-occupationally exposed humans in Canada were similar to the levels reported in a previous US study with a similar sample pool size. Two distinct PFOS isomers in human serum were identified by accurate mass determination.

Determination of mutagenic potential and organic contaminants of Great Lakes drinking water

Abstract Extracts of organic compounds were obtained, using XAD-2 macroreticular resin, from drinking water supplies in 12 Great Lakes municipalities. The extracts were tested for mutagenic potential using the Salmonella/mammalian-microsome assay and analysed for organochlorine pesticides, polyaromatic hydrocarbons, organophosphorous pesticides and trialkyl-arylphosphates. Grab samples of drinking water were also analysed for volatile organic compounds. Dose-related increases in mutagenicity were found in extracts from 11 of the drinking water supplies.

Purification and identification of several sulphonated azo dyes using reversed-phase preparative high-performance liquid chromatography

Abstract Reversed-phase preparative HPLC has been successfully used to isolate several sulphonated azo dyes (Acid Red 1, Acid Red 8, Acid Red 106, Acid Violet 5, Chromotrope 2R, Reactive Orange 16 and Cibacron Brilliant Red 3B-A) from their impurities. The separations were achieved using mobile phases of methanol and ammonium acetate. The major components of these azo dyes were collected and then identified by electrospray mass spectrometry using the characteristic ions [M−2Na]2−, [M−2Na+H]− and [M−Na]−. The degree of purification, as measured by electrospray mass spectroscopy, was variable.

The determination of N-nitrosodiethanolamine in cutting fluids

The formation of N-nitrosodiethanolamine (NDETA) from the reaction of triethanolamine with nitrite has been demonstrated by LIJINSKY et al. (1972) and also by ZINGMARK and RAPPE (1976) under simulated gastric conditions at pH 2-4. Subsequently, FAN et al. (1977) have shown that this reaction occurs in cutting fluids under alkaline conditions, pH 9-11, and have reported levels of NDETA as high as 3%. Little is known of the toxicity of NDETA, but DRUCKREY et al. (1967) have shown that it is carcinogenic in the rat. In order to assess the magnitude of the problem of NDETA contamination in cutting fluids, a limited survey was made of cutting fluids used in Canada.

Trends in levels of disinfection by-products

Levels of disinfection by-products (DBPs) in drinking water samples tended to be higher in summer than in winter. The concentrations of some DBPs tended to increase with distance (time) from the treatment plant while other DBPs increased in the first part of the distribution system and then decreased at a further distance from the treatment plant. Samples taken near the end of the distribution system provided an estimation of maximum exposure for trihalomethanes but not for haloacetic acids. Maximum values for DCAA and TCAA usually occurred at some point within the distribution system and by the end of the distribution system DCAA and TCAA levels were below their respective maximum values. No single sampling location or season provided simultaneous maximum values for the trihalomethanes and haloacetic acids. The difficulties involved in determining current human exposures to DBPs in drinking water emphasize the problems involved in attempting a retrospective estimation of DBP exposure. It will be difficult to assess the risk of adverse health effects within an exposed population when the levels and speciation of the DBPs change between seasons and the level of exposure can depend on how far the consumer lives from the water treatment plant.

Soil Fulvic Acid Degradation By Ozone In Aqueous Medium

Armadale Armadale soil fulvic acid (SFA) was found to contain several loosely bound organic impurities which could be removed by ethyl acetate extraction. The ozonation of purified Armadale SFA at a variety of dosages was characterized by monitoring the UV absorbance, weight loss, pH changes, total acidity, molecular weight and elemental composition. SFA could only be partially degraded even under ozone dosages as high as SFA/O3 (w/w) of 1:6. At high ozone dosages (SFA/O3 1:6) mostly aliphatic compounds rich in oxygen were produced, whereas at low ozone dosages (SFA/O3 < 1:0.5) mainly benzene polycarboxylic acids and polyhydroxy benzene polycarboxylic acids were found. The solid material bisolated from the chlorination (0.5 mg/L residual level) of residues from the ozonation (SFA/O3 1:0.2 to 1:0.5) of Contech SFA did not contain any chlorinated products.

Use of immobilized copper ion chromatography and on-line mass spectrometry with atmospheric pressure chemical ionization for the profiling of complex mixtures of polycyclic aromatic compounds

Abstract Immobilized copper ion chromatography was combined with either diode array detection or atmospheric pressure chemical ionization mass spectrometry for the profiling of complex mixtures of polycyclic aromatic compounds (PACs). A heated pneumatic nebulizer interface was used to convey the eluent from the column into the ionization region of the mass spectrometer. Several modifications were made to the heated pneumatic nebulizer interface originally designed for liquid chromatography-mass spectrometry so that the mass spectrometer could be safely operated with large quantities of organic solvent passing into the ionization region of the instrument. A copper-coated Zorbax 300 SCX column was used in conjunction with a hexane, chloroform and acetonitrile gradient to accomplish fractionation of three extracts containing PACs. The column was able to separate portions of the extracts into a number of fractions, each of which contained homologous series of different PAC classes. Using this technique, it is possible to gain considerable insight into the types and relative amounts of minor components present in the PAC mixtures.