Disturbances in psychological functions of workers occupationally exposed to styrene. Scand. j. work environ. & health 3 (1976) [129][130][131][132][133][134][135][136][137][138][139]. The relationship between long-term occupational styrene exposure and disturbances in psychological functions was studied. The exposed group consisted of 98 male worker,s exposed to styrene in the manufacture of polyester plastic products, and the comparison group comprised 43 concrete reinforcement workers. The duration of exposure in years and the mean mandelic acid concentration in urine (five determinattions during 5 weeks before the clinical examination) and the cumulative dose of exposure were used as the indicators of exposure. The psychological functions studied were intelligence, visuomotor speed, visuomotor accuracy, memory, vigilance, and psychomotor performance. Some personality test variables were also included. In a group comparison two variables (visuomotor inaccuracy and poor psychomotor performance) out of 20 shQwed statistically significant differences and characterized the styrene exposed group. These findings were confirmed when workers with low and high styrene exposure were compared. One variable measuring visuomotor speed and another measuring visual memory were related to the duratiQn of exposure (R =0.28, p < 0.05). In a multiple regression analysis disturbances in visuomotor accuracy, poor psychomotor performance, and lowered vigilance proved to have some connection with a high mandelic acid concentr·ation (R = 0.49, p < 0.01). In addition workers with disturbances in visuomotor accuracy and slight disturbances in visuomotor speed had higher mandelic acid concentrations when compared with thQse workers without any deterioration. The results indicate that disturbances in visuomotor accuracy and, to a lesser degree, in psychomotor performance are the main findings measured by test methods used in this study and related to one indicator of styrene exposure, mandelic acid concentration. The psychological methods used revealed subc1inicaI symptoms relared to exposure, and they shou'ld aid in making group diagnoses, e.g., when additional 1nformation is needed for the determination of the threshold limit value. The deterioration found in visuomotor accuracy could be related to lowered s'afety in work and traffic.

Urinary mandelic acid concentration after occupational exposure to styrene and its use as a biological exposure test. by Engström K, Härkönen H, Kalliokoski P, Rantanen JThe following article refers to this text: 1980;6(2):158-160

findings among workers occupationally exposed to styrene. Scand. j. work environ. & heaUh 3: (1976) 140-146. Ninety-six male workers oc'cupationally exposed to styrene in 24 plants producing reinforced polyester plastic products were studied neurophysiologically. The mean age of the subjects was 29.6 ± 7.4 years, and the duration of the exposure varied from 6 months to 14 years (mean 5.0 years). Mandelic acid concentration in the urine (mean of five values determined during five consecutive weeks) was used as the measure of exposure. The individual means of the mandelic acid concentrations varied from 7 to 4,715 mg/dm 3 (median 808 mg/dm 3 ). Neurotoxic effects of styrene exposure upon the central nervous system were revealed by abnormalities in the EEG. The overall prevalence of abnormal EEGs was· 24 Ofo (23 out of 96), which is higher than that found among a normal population (p < 0.05). Abnormal EEGs were found in one-third of the subjects with relevant styrene exposure (mandelic acid concentration over 700 mg/dm 3 ), while low-level styrene exposure did not increase the prevalence of normal EEGs above that found in a normal population. Nerve conduction velocity measurements performed on 40 subjects did not reveal any definite relationship between neuropathy and styrene exposure. The EEG examination is useful in the investigation of the neurotoxic effects of styrene. Whenever a possibility exists of excessive styrene exposure or beginning poisoning, the workers should be submitted to an EEG examination.

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