Document G6dOrE98x05eadMQYxnZEaNev

it. J. industr. Med.. 1971, 28, 293-295 Evaluation of the psychophysiological functions in humans exposed to trichloroethylene '1. SALVINI, S. BINASCHI, and M. RIVA1 istitute of Preventive Medicine for Workers and Applied Psychology, University of Pavia, Italy Salvini, M., Blnaschi, S., and Rlva, M. (1971). Brit. J. industr. Med., 28, 293-295. Evaluation of the psychophysiological functions in humans exposed to trichloroethylene. To provide data on the psychophysiological efficiency of human beings exposed to solvent vapour currently used in the industry the effectsof trichloroethylene (TCE) were evaluated by exposing six male university students to an averagevapour concentration of 1 lOp.p.m. for two 4-hour exposures, separated by a 1 J-hour interval. Each subject was examined on two different days, on one day undertaking a set of tests in an atmosphere contaminated with TCE vapours and on another day in a `control' atmosphere which did not contain TCE. On each of the two days two sets of test were performed at 8.30 a.m. and at 6 p.m. The following tests were performed: perception test with tachistoscopic presentation, Wechsler Memory Scale, complex reaction time test, and marfiial dexterity test. (K crossed scheme----- analysis was usedr-fn all the tests performed a statistically very significant decrease in per- formance ability was seen; the greatest decrease occurred during the more complex tests. The suggested TLV for TCE (100 p.p.m.) appears to be very close to the average concentration / capable of interfering with psychophysiological efficiency, even in the absence of other / undesirable subjective and objective manifestations. ^ I \periments performed on experimental animals to :-certain the effects of trichloroethylene (TCE) ' tpour have shown that this substance interfered " oh their psychophysiological efficiency (Grandjean < id Battig, 1964). Recently, experiments have been conducted to i id whether the same phenomenon occurs in 1 itnans. In one experiment, a human subject was 'posed to four concentrations of TCE for 2 hours -i minutes. The results indicated that at the TLV of 1 CE (100 p.p.m., as recommended by the American 1'inference of Governmental Industrial Hygienists, |lMi71, no significant effects occurred in human U-M-areh Laboratory Star Food Co. Ltd., Milan. Address requests for reprints to: Istiluto di Medicina I'u-'eiiti'a dei taioratori, 24, sia Boe/to - 27100 Pa\ia "Uhl psychomotive efficiency (Stopps and McLaughlin, 1967). This conclusion may be questioned on two grounds: firstly, all of Stopps's experiments were performed for a limited period, not comparable to the 8-hour working day; secondly, the results are of somewhat limited value because only one human being was exposed. Therefore, to provide more realistic and reliable information on the psychophysiological efficiency of human beings exposed to solvent vapours currently used in industry, a research programme was initiated to evaluate the effects on six persons exposed to TCE at an atmospheric concentration of 110 p.p.m, for 8 working hours. Methods The effects of TCE were evaluated by exposing six male 293 SL 034X97 'ua>ini, > />#/((\<///, anu 'J A/iii univcivity students, beI ween 20 and 22 years of age, to an TABLE 2 average vapour concent ration of I lOp.p.m.and fluctuations between 90 p.p.m. anil 130 p.p.m, TCE was periodically^ Immediate Memory Test - Analysis ot VariAS( atomized into the test room to maintain tKc desIrSa concentration. The air was analysed at regular intervals by gas-chromatography. The temperature, humidity, and SSQ D.F. S* / ventilation rates were kept constant (dry bulb temperature 20 relative humidity 45 ",',). Details of the experimental method are similar to those given in the companion paper (Salvini, Binaschi. and Riva, 1971). During each exposure the following tests were applied (for details, see the companion paper): 1. Perception test with tachistoscopic presentation Trichloroethylene (TCE) Mental fatigue (MF) TCE MF Learning (L) L * MF Subjects (S) S - FM Error 462-68 85-58 216-74 295-88 160 55 547-75 116 155 01 1 1 1 1 1 5 5 8 462-68 85 58 216-74 293 88 160 53 69 55 23-20 16 88 27 5 13 17 . * A 1 (exposure time 1/20 sec) - to evaluate the extension of the perceptive field, the span of perception, and the organ p < 0 05 *p < 0-01 *p < 0 001 izing capacity of stimuli in space: 2. Weehsler Memory Scale - to evaluate immediate memory and the perceptive field extension; 3. Complex reaction lime - to evaluate the time lapse between different visual stimuli and the correct psychomotive response and the regularity between stimuli and TABLE 3 Complex Reaction Times (Speed of Responses Analysis of Variance response intervals. ; Manual dexterity tests involving the right, left, and both hands simultaneously were also conducted. SSQ D.F. S' 1 Results From an objective clinical standpoint, no dis turbances in motor functions, co-ordination, equi librium or behaviour patterns were observed after two 4-hour exposures to TCE. A slight sense of Trichloroethylene (TCE) Mental fatigue (MF) TCE x MF Learning (L) L x MF Subjects (S) S x MF Error 119-72 77-04 127-37 87-71 46-44 162-80 105 .36-68 1 t 1 1 1 5 J 8 119-72 77-04 127-37 87-71 46-44 32-45 21 4-38 2U 1 16 s 27 s 19 1 10 1 71 4< dizziness coincided with the maximum fluctuations in TCE concentrations. During these periods some 'p < 0 05 *p < 0-01 1 p < 0 001 transient eye irritation was observed. All the test subjects complained about the odour of TCE. In all the tests performed there was a statistically TABLE 4 significant decrease in performance ability; the greatest decrease occurred during the more complex experiments (Tables 1 to 5). Complex Reaction Times (Regularity Ot Responses) - Analysis of Variance SSQ D.F. S' F Table I Perceptive Test - Analysis of Variance Trichloroethylene (TCP ) Mental fatigue (MFl TCP MF Learning (L) L MF Subjects (S) S MF f rror SSQ 28-12 2-54 15-81 55-02 15 75 5860 15-10 8 11 DP. 1 1 1 5 5 8 S' F 28-12 2-54 15-81 5502 15-75 7-72 502 101 27-84* 2-52 15-65* 54-67* 15-59* 7-64` 2-99 >p 1 0 05 *f V 0 01 *p < 0 001 SSQ ,>um of square about the mean O F degrees of freedom S* estimate of variance F Snedeeor's variance ratio Trichloroethylene (TCE) Mental fatigue (MF) TCE x MF Learning (L) L s MF Subject (S) S x MF E rror 132-54 19 65 22-86 18-48 8-76 108-95 101 -45 85-41 1 1 1 1 1 5 5 8 001 132-54 19-65 22-86 18-48 8-76 21-79 20-29 10-68 12 -i Is :-i !' o. :!1* Discussion Our results indicate that the suggested TLV trichloroeihylene(IOOp.p.nt.)appears to be very clto the average concentration capable of cansignificant decrements in the functions essential the safety of workers performing indust i operations. l.valiiiiiioti TABLE { Manual Ariliey and De\ Variani 3-V0 () Piftitt ham! Trichloroethv lene Learning Subjects Error 480-11 173-61 295 95 75-42 () Left hand Trichloroethylene Learning Subjects Error 85-59 57-79 401-85 1451 (e) Right and left hands Trichloroethylene Learning Subjects Error 71-88 68-88 508-65 1051 ip < 0-05 *p < 0 01 At first it was thought tf could not be regarded as rep: the complaints and reactions the odour of TCE. These reac psychological in nature becat never before exposed and ther to the odour of TCE. Neverth if and to what degree this fa results. For this reason, the exi using as the subjects six woi work with TCE and other so the experiments with worker; elusions already drawn from th< and summarized in Tables 1 t< 03A198 / Evaluation of the psychophysiological functions in humans exposed to trichloroethylene 295 TABLE 5 Manual Ability and Dfxterity Analysis of Variance SSQ n.F. S' F i Rifjhr hand Trichloroethylene L earning Subjects l: rror 480 11 1 480-11 25-47* 173-61 1 173-61 9 21' 295-95 5 59-19 3-14 75-42 4 18-85 i Lt'ft hand Trichloroethylene Learning Subjects F rror 83-39 37-79 401-85 14-51 1 1 5 4 83-39 37-79 80*37 3-63 23-80* 10-41* 22-14* l Right and left hands Trichloroethylene learning Subjects Error 71-88 68-88 308-65 10-51 1 1 5 4 71-88 68-88 61-73 2-63 27-33* 26-19* 23-47* < 005 *p < ooi At first it was thought that these experiments ould not be regarded as representative because of lie complaints and reactions of the students about he odour of TCE. These reactions were considered 'sychological in nature because the students were ievcr before exposed and therefore not accustomed 0 the odour of TCE. Neverthless, it was not known 1 and to what degree this factor affected the test esults. For this reason, the experiment was repeated ising as the subjects six workmen who regularly uirk with TCE and other solvents. The results of lie experiments with workers confirmed the con tusions already drawn from the results with students ind summarized in Tables I to 5. Conclusion Two 4-hour exposures, separated by a I.J-hour interval, to trichloroethylene at an average con centration of 110 p.p.nt., with fluctuations ranging from 90 p.p.m. to 130 p.p.m., caused a statistically significant reduction in efficiency of both students and workers in performing various psychophysiological tests. The reduction in efficiency is particularly significant in those tests involving perceptive dis crimination. Therefore, it is possible that a TLV of 100 p.p.m. for trichloroethylene may result in interference with the psychophysiological efficiency of a man with executive or technical responsibilities even in the absence of other undesirable subjective and objective manifestations. References Grandjean. E., and Bittig, K. (1964). Le spectre des cflets du trichlortthyline sur le comportetnent du rat. Arch. im. Pharmacodyn.. 147, pp. 333-350. Horvath, M., Frantik, E.. and Michalovi, C. (1964). The research of higher nervous functions in occupational health. Proc. XIV int. Congr. occup. Hlth Madrid, 1963, vol. It, pp. 93-105. Excerpta med. Int. Congr. Ser. No. 62. Lyublina, E. 1. (I960. Some methods used in establishing the maximum allowable concentrations. Pure appl. Chem.. 3, 109-113. Salvini, M., Binaschi, S., and Riva, M. (1971). Evaluation of the psychophysiological functions in humans exposed to the threshold limit value of 1,1,1-trichloroethane. Brit. J, industr. Med., 28, 286-292. Stopps, G. J., and McLaughlin. M. (1967). Psychophysioiogical testing of human subjects exposed to solvent vapors. Amer. industr. Hyg. Ass. J., 28,43-50. ReceivedTor publication March 21, 1970. SL 034199