Rein Otson

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.

A review of techniques for measurement of airborne aldehydes

The literature on aldehyde measurement methods was surveyed and critically reviewed to determine which methods would prove most suitable for monitoring personal exposure to a number of aldehyde compounds that have been found in air. A variety of methods was found that were applicable to measurement of specific aldehydes. Some of these were based on instrumental and spectrophotometric analytical methods. Others, based on direct sorption of aldehydes on solid sorbents with subsequent instrumental analysis, were developed and validated only for one or two aldehydes in air. The most promising techniques involved derivatization with one of several available agents (e.g., N-benzylethanolamine, 2,4-dinitrophenylhydrazine) and, most commonly, extraction and analysis using chromatographic (HPLC or GC) instrumentation. Even these, however, were not found to be fully validated methods suitable for the concurrent measurement of several aldehydes.

Evaluation of a liquid-liquid extraction tecnique for water pollutants

Abstract A simple liquid-liquid extration technique was evaluated and judged to be useful for semiquantative determination of 37 oranic pollutants present in water at concentrations of 50μg/1 for 30 compounds, recoveries of ≥ 80% for 20 compounds and, generally, peak area precision of better than ± 5% for triplicate sample analyses. Storage of aqueous standard solution at 4°C for 4 week did not significantly affect recovery values.

Examination of sampling methods for assessment of personal exposures to airborne aldehydes

A personal exposure monitor was required for the determination of airborne aldehyde exposures caused by emissions from methanol-fuelled vehicles. Derivatization of aldehydes during collection was selected as the technique to enhance the integrity of samples and to facilitate analysis. Three derivatization agents, HMP [2-(hydroxymethyl)piperidine], BEA (N-benzylethanolamine) and DNPH (2,4-dinitrophenylhydrazine), were examined. High blank levels and poor chromatographic resolution of some of the derivatives discouraged the use of BEA and HMP, whereas DNPH derivatization allowed good sensitivity and resolution of the hydrazones of formaldehyde, acetaldehyde, acrolein, crotonaldehyde and benzaldehyde. Passive and active samplers containing DNPH-impregnated XAD (ORBO-43) and glass-fibre filters were evaluated for the determination of airborne aldehydes at several concentrations in the range 10–5000 µg m–3. Although analytical detection limits were better than 40 µg m–3, sampler blank values limited practical detection limits to 50–100 µg m–3 for the individual aldehydes. The analytical precision relative standard deviation approximately 20%, based on results for samplers deployed in triplicate in a test atmosphere. The effects of humidity, air velocity and concentration of aldehydes on the sampling characteristics of active and passive samplers were measured. Some discrepancies, particularly for the unsaturated aldehydes, were noted for results obtained with the different sampling procedures in controlled-atmosphere chamber tests. These results suggested that, after further development, a DNPH-based passive sampling method could meet the required performance criteria.

Sample Handling and Analysis for 51 Volatile Organics by an Adapted Purge and Trap GC-MS Technique

Abstract An adapted, purge and trap GC-MS technique using heated, 100mL aqueous samples was evaluated for the determination of organics in a water quality survey. The 51 volatile organics consisted of 7 aromatic, 40 halogenated aliphatic and aromatic, and 4 other compounds and included the purgeable priority pollutants listed by the U.S. E.P.A. Detection limits 70%, and precision < 20% RSD for recoveries over all three concentrations were generally obtained for the 51 standards, each spiked at 1, 10, and 50μg/L into purified water. The few instances of abnormal recoveries, poor detection limits, and poor analytical precision were often related. Improved detection limits were obtained for several water soluble and a few halogenated compounds when the concentrator trap composition was changed, transfer line temperature was decreased, and the sparger vessel temperature was increased. For survey control samples, i.e. spiked purified water in bottles transp...

Purgeable Organics in Great Lakes Raw and Treated Water

Abstract The occurrence of 51 volatile organics in water supplies at nine municipalities along the Great Lakes and for a well water supply was examined by a GC-MS technique. Only dichloromethane (max. 19.0μg/L) and chloroform (17.0μg/L) were detected at concentrations above 10.0 μg/L and bromodichloromethane, chlorodibromomethane, dichloroacetonitrile, toluene, and styrene were detected at least once above 10.0μg/L. Aggregate levels of the 19 organics detected at ≥ 0.1 μg/L were generally about the same in treated and raw water when values for trihalomethanes (THM) and dichloroacetonitrile were excluded. THM values did not exceed 32μg/L. The aggregate frequency and the mean of aggregate organics levels were noticeably lower for raw water in winter than in summer or spring. Overall, the water treatment at the sites was not very effective in removal of relatively low levels (0.1 to 5 μg/L) for the volatile organics from raw water. There were no evident trends to the occurrence of organics along the Great La...

Relationships between raw water quality, treatment, and occurrence of organics in Canadian potable water.

The occurrence of organic contaminants in potable water is of concern since ingestion of such compounds may pose a hazard to human health. To aid in health hazard assessment, Canadian potable water supplies have been surveyed for the occurrence of organic compounds, such as, the trihalomethanes (WILLIAMS et al. 1980) and n i t r i l o t r i a c e t i c acid (MALAIYANDI et al. 1979). A wide range of organics have been reported to occur in potable water (GARRISON et al. 1978) and sources of such contaminants have been discussed (e.g., DEINZER et al. 1978, WAGGOTT & WHEATLAND 1978). The relat ionships between the occurrence of organics, raw water qual i ty , and treatment practices have been investigated (e.g. SYMDNS et al. 1975, WILLIAMS et al. 1980, OTSON et al. 1981). However, such studies have been l imited, generally, to the occurrence of trihalomethanes (THM). During a recent survey of water at 30 Canadian potable water treatment f a c i l i t i e s , the occurrence of about 40 vo la t i le organics was investigated (OTSON et al. 1982). Subsequently, data obtained from questionnaires completed during the survey were used to explore the relat ionships between the occurrence of organics, water qual i ty , and treatment practices. Results of these investigations are now reported.

Mutagenicity of paint removers containing dichloromethane

A volatile component of commercially available paint and varnish removers was mutagenic in strains of Salmonella typhimurium TA1535, TA100 and TA98. Levels of dichloromethane in exposure chambers were determined by gas chromatography and were related directly to mutational dose-effect curves observed for the products.

Dichloromethane levels in air after application of paint removers

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.

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

ConclusionsThe 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.