H. A. Waldron

Neurobehavioural effects of repeated occupational exposure to toluene and paint solvents.

In studies of two workforces 44 men exposed to paint solvents and 52 men working with toluene were compared with age matched comparison groups of non-exposed workers. Scores on a series of performance tests were examined, the solvent exposed in each study functioning less well than their comparison group. The apparent deficit among the paint exposed workers was substantial, but this was reduced after allowance for estimated intellectual capacity. No deficit was apparent on rematching with a second comparison group of more appropriate measured capacity. No evidence was found of impaired nerve conduction in the ulnar or median nerves, and few clinical signs of neurological damage were apparent. Nevertheless, in an associated inquiry of neuropsychological symptoms among 236 painters and 128 non-exposed workers a highly significant excess of symptoms was found among those exposed to paint solvents.

The effects of ethanol on blood toluene concentrations.

SummaryThe metabolism of toluene was found to be inhibited by a large dose of alcohol in seven volunteers exposed to 80 ppm of toluene under experimental conditions. When alcohol was taken during exposure, blood toluene concentrations were 42.5% greater on average than during exposure with no alcohol. This is probably due to competition for alcohol dehydrogenase which is required for the breakdown of both ethanol and toluene.In men exposed to toluene at work, it was found that blood toluene concentrations were lowest in those who drank regularly. These results suggest that continued alcohol intake increases the metabolism of toluene, presumably by inducing the microsomal oxidising enzyme system in the liver.

An investigation of the acute behavioural effects of styrene on factory workers.

A group of men exposed to styrene in a factory building glass-fibre boats performed a series of behavioural tests at the beginning and end of their shift, and the results were compared with those of a referent group from the same factory. Changes in mood were noted in both groups of workers but were greater in the exposed men; moreover, the change in mood was correlated with blood styrene concentration. In the styrene workers the morning reaction time was slower than that for the referents. During the day the reaction time of the men with low blood styrene concentration (less than or equal to 5.4 mumol/l) speeded up and in the afternoon was similar to that of the referents; the reaction time for the men with high blood styrene concentration (greater than or equal to 5.5 mumol/l) was unchanged. Data taken from a questionnaire indicated that the men exposed were much more likely than was the referent group to report feeling unduly tired. They also reported feeling more tired on Friday night than Monday night, suggesting that the styrene might have a cumulative effect through the week.

THE EFFECTS OF TOLUENE AND ALCOHOL ON PSYCHOMOTOR PERFORMANCE

Eight male subjects took part in four experimental sessions in an exposure chamber to assess the effects of toluene (80 p.p.m.) and alcohol (0.4 ml per kg body weight) individually and in combination on four measures of performance and also on mood. Alcohol caused a significant deterioration over the exposure session in performance on pursuit tracking and visual search tasks and also in mood. Toluene had no significant effect on any of the behavioural measures, but examination of mean scores for each treatment suggested a tendency for performance and mood to deteriorate more when alcohol and toluene were administered together than when alcohol was taken alone.

Acute behavioral effects of styrene exposure: a further analysis.

Studies were carried out on two groups to styrene-based resin. Early morning urinary mandelic acid concentrations after two days without exposure correlated with reaction time measured on arrival at work. Men were found to differ considerably in their rate of clearance of mandelic acid-those with slow reaction times. After some months at reduced exposure, a small group of men with previously high mandelic acid concentrations has speeded up on the reaction time task.

Some observations on workers exposed to methylene chloride.

An excess of self-reported neurological symptoms was found when a group of 46 men exposed to methylene chloride at concentrations below 100 ppm was compared with a non-exposed referent group. A follow-up study was then carried out to see whether there was any evidence of neuropsychological damage in the exposed men. Twenty-nine of the original group participated in this study. Age-matched controls controls were selected from among men working on a similar process but with no exposure to solvents. Each man in the study had a clinical examination; motor conduction velocities were measured in the ulnar and median nerves; an ECG was taken and a psychological test battery was designed to detect minimal brain damage was administered. No evidence was found of long-term damage that could be attributed to exposure to methylene chloride.

Solvent sniffing in industry.

the non-skilled manual workforce are exposed to them in the course of their work. The problem of addiction to solvents at work is often alluded to by company medical officers and almost every occupational physician who has worked in a solvent using industry has anecdotal evidence which appears to lend support to the centention of Ethel Browning (1965) that, ’addiction to trichloroethylene is a relatively frequent occurrence.’ Hard evidence on the prevalence of sniffing in industry, however, seems to be non-existent. Case reports of deaths (Cragg & Castledore, 1970; Kleinfeld & Tabershaw, 1954; Northfield, 1981; Stahl et al., 1969) and of acute psychiatric manifestations (Braceland, 1942; Capurro & Capurro, 1979; Tarsh, 1979) brought about by exposure to solvents at work can be found in a wide range of journals. In some reports, sniffing is implicated, especially in those which may be called the ’sudden death syndrome’. In these cases, death typically occurs in a young solvent worker after some sudden exertion, such as running up a flight of stairs. The explanation which is most often