THE PSYCHOLOGICAL EFFECTS OF CHRONIC

Polish Journal of Occupational Medicine Vol. 3, No.
1, 117-127
117-128, 1990
THE PSYCH O LO G ICAL EFFECTS O F CH RON IC EXPOSURE
TO WHITE SPIRIT IN RUBBER INDUSTRY WORKERS
BARBARA BAZYLEW ICZ-W ALCZAK,
ALEKSANDRA SIUDA
MAGDALENA MARSZAL-WISNIEWSKA and
Department of Work Psychology, The Nofer Institute of Occupationl Medicine,
Lodz, Poland
K ey words: Organic solvents, Psychological functions, Cross section study,
Occupational long-term exposure
Abstract. The aim of the study w as to determ ine the effects o f ch ron ic o c ­
cu p a tion al exposu re to w hite spirit on the efficie n cy o f w ork ers’ in tellectual
an d psych om otor function s. The ex p osed grou p consisted o f 226 rufaber in ­
du stry w ork ers w h ile the con trol g rou p com prised 102 hosiery plant w ork ers.
T h e analysis of results w as aim ed at the determ ination o f ex posu re effects
depen din g on the du ration o f exposu re and age o f persons exam ined. It has
■been revea-led that ch ron ic exposu re to w hite spirit, at a con cen tration close
to the hygienic standard, induces the deterioration o f som e intellectual and
p sy ch om otor fu nction s in the ex p osed persons, depen din g on the duration o f
ex p osu re and age o f the ex p osed subjects.
A m on g the variables presen ted in the study, several in dividu al fu nction s in­
clu d in g: perception and reprodu ction o f visu al m aterial; p rojection o f spatial
relation sh ips; concentration; tim e o f sim ple and ch oice reaction ; speed and
coord in a tion o f hand m ovem en ts, w ere fou n d the m ost e ffectiv e in contrasting
th e exposed group from the control.
INTRODUCTION
Nervous tissue, due to its biochemical structure, is selectively sen­
sitive to the effect of organic solvents. Intoxication may result in demyelination both in the central and peripheral structures of the nervous
system (1). Symptomatology of the neurotoxic effect of organic solvents
considerably precedes damage to the hematopoietic system and paren­
chymatous organs. It is thus to be expected that changes within psy­
chical functions will be the earliest detectable effects of intoxication.
Moreover, as previous studies have shown (8), psychological techniques
more easily detect early CNS disturbances due to solvents than tradi-
A dd ress reprin t requests to B arbara B azylew icz-W alczak , D epartm ent o f W ork
P sy ch olog y , The Nofej: Institute o f O ccupational M edicine, P.O. B o x 199, 90-950
L odz, P ola n d
118
B. Bazylewicz-Walczak et al.
tional medical examinations. Hence, the role of psychological tests in
the evaluation of the effects on health of chronic occupational exposure
to organic solvents seems to be particularly significant.
White spririt is one of the most wiclely used organic solvents (e.g.:
as a component of glues, varnishes and paints). Medical studies dominate
among the p'apers on white spirit toxic effects while psychological stu­
dies refer mainly to the effects of toxic mixtures with white spirit as
one of the components. Most of these studies were carried on in the
1970s and 1980s in the Scandinavian countries (3, 4, 5, 6, 7, 9, 10, 11).
This study deals with - the evaluation of the psychological effects
of chronic exposure to white spirit contained in the glue used for rubber
footwear production.
The investigations presented were aimed at determining the effect
of the solvent mentioned on selected mental and psychomotor functions
of exposed workers, and were carried out at the Nofer Institute of Oc­
cupational Medicine, Lodz within a research programme concerning the
evaluation of the state of health of exposed workers.
MATERIALS AND METHODS
In accordance with the aim of the studies, a group of persons chro­
nically exposed to white spirit was compared with a control group. The
exposed group consisted of workers — most, of them women — emplo­
yed in belt-system production of rubber footwear, continuously perfor­
ming one activity (gluing footwear elements) in a sitting position during
the whole of each shift. ’As could be seen from the plant’s documenta­
tion, the white spirit concentrations in this department have been close
to the Polish hygienic standard value (500 mg/m3) for 13 years. It was
assumed that potential disturbances of behaviour, being the symptoms
of chronic intoxication, should be expected only after a few years’ ex­
posure. Therefore, the basic criterion of choice was at least 5-years’
occupational exposure. Measurements of exposure were carried out by
team of chemists from the Nofer Institute of Occupational Medicine, on
the basic of air samples collected during one shift. The analysis of the
white spirit concentration in the air was made by means of gas chro­
matography with a flame ionization detector. ..Detectability of this met­
hod amounts to 25 mg/m3 for white spirit. The results of the measu­
rement confirmed that white spirit concentrations in the workers’ respi­
ratory zone remained at Maximal Acceptable Concentration level.
Chemical analysis of the gue used, shewed that white spirit was its only
toxic component. The exposed group comprised 226 persons: 202 women
Psychologic cffects of exposure to white spririt
119
and 24 men. The control group consisted of workers unexposed to
chemical substances. These were the employees of hosiery plants (seam­
stresses and knitters), performing work of a similar level of difficulty
and complexity as the exposed group. The selection criterion here was
the compatibility of these worker’s sex, age, education level and dura­
tion of employment with those of the exposed workers. The group com­
prised 102 individuals: 91 women and 11 men.
According to the aim of the study, the selected mental and psycho­
motor functions of workers belonging to the groups distinguished, were
examined. Within intellectual functions the following were examined:
— visual analysis and synthesis processes
— verbal memory
— sensory-motor speed and coordination
— concentration span
— mental capacity (speed and correctness of intellectual operations)
— spatial imagination (projection of spatial relationships)
— correctness of perception and reproduction of visual material.
These functions were examined by means of Block Design, Digit
Span, Digit Symbol from the Wechsler Adult Intelligence Scale, the
Toulouse-Pieron Test (12), the Kraepelin Test (12), the Dots Location
Test from Test for Mechanical Ability T.W. MacQuarry (2) and the Ben­
der Test (13).
Within psychomotor functions the reaction times (the speed and
correctnes of responses to simple and complex light stimuli) and manual
dexterity were examined. Three methods were employed here: Visual
Reaction Time, Pegboard (14), One-and Two-Plate Tapping. Apart from
these, a questionnaire was used which aimed at gathering supplementary
information on smoking, alcohol consumption, taking medicines and
verifying the proper allocation of persons to the groups examined.
STATISTICAL METHODS
Statistical analysis included: determination of the level of signifi­
cance of the differences between particular variables — mean values
with Student’s t-test for 2 independent samples and discriminant
analysis.
RESULTS
According to the procedure applied, each person examined was
characterized by means of a set of variables, the numerical indices of
which were constituted by the results obtained by the examinee ip.
120
B. Bazylewicz-Walczak et al.
particular tests. In Tables 1 and 2 mean values of particular variables
in the exposed and control group were compared, taking the age
sub-groups into consideration.
Results in Table 1 show that of the intellectual variables examined,
the following variables most strongly differentiated both groups (the
whole groups and the age subgroups):
— correctness of perception and reproduction of visual material
(Bender Test)
— correctness of projecting spatial relationships (Dots Location
Test), as well as
— mental efficiency and long-lasting attention concentration (Kraepelin Test).
In addition, some significant differences in associational memory,
sensory-motor speed and coordination (Digit Symbol) as well as in visual
analysis and synthesis (Bloc Design) were found between the exposed
and unexposed individuals aged 46— 60 years.
The results presented in Table 2 indicate that among the considered
psychomotor variables the highest diversity (between whole groups and
age sub-groups) occurred in the speed and correctness of responses to
light stimuli (simple and complex reaction). Moreover, some differences
were found in manual dexterity, speed and coordination of hand move­
ments (One- and Two-Plate Tapping) between the tested groups inclu­
ding individuals aged 46— 60 years.
In order to determine the dynamics of all the variables studied in
the exposed individuals, they were divided into three sub-groups accor­
ding to the period of work under conditions of exposure (5— 10 years,
11— 15 years, 16— 30 years). The comparisons between these sub-groups
showed (Table 3) that there were no statistically significant differences
in the results such as: efficiency and errors in Tbulouse-Pieron Test,
efficiency in Dots Location Test, One-Pl'ate Tapping and Peg'board.
However, a statistically significant deterioration of performance was
found in such variables as: Kreapelin Test or simple and complex
reaction time, proportional to exposure duration.
Discriminant analysis made it possible to separate a set of variables
which most strongly discriminated between both groups: the group
of persons chronically exposed to white spirit and the control. The
results presented in Table 4 indicate that the set of 11 variables is the
best for the discrimination of the tested groups. This set also includes
personality variables which are not, however, taken into consideration
in this study, but they haven been included in a more comprehensive
study (unpublished data).
Psychologic effects of exposure to white spririt
121
DISCUSSION
The studies carried out have proved that long-term exposure to
white spirit, at concentrations close to MAC, brings about the deterio­
ration of workers’ intellectual and psychomotor functions. There are
some functions which deteriorate even in workers exposed for the shor­
test period of time, i.e. from 5 to 10 years. As far as
intellectual functions are .concerned this refers to the correctness
of perception and reproduction of visual material, projection of spatial
relationships, mental capacity and long-term concentration, while
within psychomotor functions — the speed and correctness of reactions
to light stimuli. It should be stressed that the correctness of perception
and reproduction of visual material, measured with the Bender Test
and expressed in standardized units “ Z” , amounted to 98 — in the
exposed group, which is almost pathological according to the clinical
standards mandatory in Poland, and reached 64 in the control group,
which remains within the standard limits. The results of the Kraepelin
Test: a higher coefficient of errors and worse test performance effi­
ciency, suggest fatigability of exposed group when compared with the
control one. Thus, the ability to perform work requiring long-term con­
centration is significantly decreased in the exposed group.
Moreover, the weakening of some functions after the longest expo­
sure (16— 30 years) has been found. These are as follows: sensory-motor
speed and coordination, visual analysis and synthesis, and manual
dexterity. This fact is supported by comparison of the exposed and
unexposed persons in the highest age group (46— 60 years) and results
from the correlation between the duration of exposure and the age of
workers examined (r =, 0,44; p = 0,001). In the exposed persons the
majority of deteriorating functions remain, at a constant level irrespec­
tive of duration of exposure. These are: mental capacity and long-term
concentration, accuracy of projection of spatial relationships, correctness
of reactions to light stimuli, and manual dexterity. Moreover, it has been
found that such functions as the speed of reactions to simple arid com­
plex light stimuli and sensory-motor speed and coordination, deteriorate
proportionately to the length of exposure. The fact that deterioration
of some functions was observed only in workers exposed for the lon­
gest period of time, should also be explained. Although in these studies,
the duration of exposure of examined persons is known, there are no
precise data on its magnitude during the entire period of exposure. The
observed magnitude of exposure, remaining within MAC limits or sligh­
tly exceeding them, may be reliable for the last 13 years, whereas pre­
viously, under other room and technical conditions within the industrial
1.
Intellectual
Span
Design
Test
Digit
Block
Bender
Kraepelin Test
efficien cy
% errors
. e ffic ie n cy
% errors
e fficie n cy
% errors
e ffic ie n cy
% errors
Toulouse-Pieron
efficie n cy
errors
e ffic ie n cy
errors
e ffic ie n cy
errors
e ffic ie n cy
errors
Sym bol
Digit
Test
Test V ariable
TABLE
III
II
I
Total
III
II
I
T otal
11
III
T otal
I
IX
III
T otal
I
II
III
1
Total
II
III
Total
1
results
Subject in
groups
test
standard
129.50
35.85
142.57
30.64
134.26
34.68
.110.53
41.16
664.70
4.19
672.00
2.90
708.93
3.03
1541.31
7.25
7.70
8.35
7.80
7.27
19.80
22.05
20.89
16.52
.62.32
54.80
58.01
74.46
29.54
39.27
31.30
22.29
37.28
35.96
34.85
13.56
34.93
37.33
38.51
38.20
263.38
'5.42
224.70
3.62
251.21
3.20
277.20
8.65
,1.31
1.19
1.27
1.31
6.60
5.10
6.37
6.40
21.97
16.19
20.00
23.07
10.02
9.01
9.33
6.41
SD
deviations)
Exposed grou p
N = 226
and
Mean
(means
for
groups
and
129.80
30.02
135.06
25.36
.134.82
32.42
116.00
32.70
767.53
1.9
797.69
1.83
836.15
1.63
666.03
2.10
7.90
8.06
7.91
7.67
21.08
22.34
20.85
19.94
31.08
32.22
26.21
34.73
age
1.00
29.87
22.25
32.99
21.47
28.89
20.57
22.19
23.82
252.48
2.21
240.09
1.84
285.92
2.33
190.69
2.43
1.12
6.30
7.22
6.00
5.18
20.56
22.99
13.86
22.33
1.10
1.15
9.06
7.45
7.46
7.18
SD
for
Control group
iN = 102
32.91
38.84
33.30
26.03
Mean
whole
NS
NS
'NS
NS
NS
NS
NS
NS
NS
NS
0.01
0.02
0.05
0.01
0.001
0.001
0.001
0.001
0.001
0.001
NS
NS
NS
NS
NS
NS
NS
0.01
0.01
-NS
INS
0.02
S ign ifican ce
level fo r
S tudent’s test
su b-grou ps
122
B. Bazylcwicz-Walczak ct al.
I age
II age from
III age from
III
II
I
Total
to 30 years
31 to 45 years
46 to 60 years
Dots Location Test
efficiency
errors
efficiency
errors
efficiency
errors
efficiency
errors
exposed group
m= 20
¢1 = 124
n= 64
19.25
7.76
24.43
7.86
20.59
7.22
13.25
9.35
11.06
7.22
7.83
6.35
11.15
6.26
9.75
■9.39
control group
n = 36
m= 33
m=33
21.70
4.80
23.25
4.36
22.94
4.67
18.48
5.33
12.35
4.88
15.23
4.85
10.67
5.24
9.50
4.48
NS
NS
0.05
NS
0.05
0.05
0.10
0.001
Psychologic effects of exposure to while sprint
123
2.
Psychomotor
Reaction
(ms)
Time
I age
II age from
III age: from
Pegboaxd
{time in s)
results
T otal
I
II
III
Total
I
II
III
Total
I
II
III
Total
I
II
III
T otal
I
II
III
T ota l
I
II
III
T ota l
I
II
III
S u b ject
in groups
test
to 30 years
31 to 45 years
46 to. 60 years
Tapping
Two-Plate
time
Tapping
Reaction
i(ms)
One-Plate
Mean
COMPLEX
REACTION
TIME
No. of 'Correct responses
Mean
SIMPLE REACTION
TIME
No. of correct responses
Test Variable
TABLE
standard
exposed group
n= 20
11 = 142
n= 64
25.90
26.80
26.06
25.27
429.20
350.35
424.84
463.62
14.94
.14.50
15.13
14.59
692.85
539.45
590.59
■614.22
171.40
179.45
174.65
161.78
126.90
•138.35
127.34
122.36
60.41
56.90
59.40
63.47
'
3.55
0.68
3.23
4.52
152.22
117.42
146.25
163.97
2.74
3.57
.2.50
2.90
107.70
87.64
108.27
112.52
28.90
24.12
27.90
30.05
24.58
22.90
23.63
25.82
7.92
7.24
7.58
7.94
SD
'
deviations)
Exposed group
N = 2 26
and
Mean
(means
for
and
for
control grou p
n=36
n=33
n=33
0.63
0.16
0.88
0.62
70.00
45.00
78.00
76.00
.1,35
4.23
1.13
1.61
86.00
51.00
87.00
89.00
28.37
31.04
32.29
18.83
25.24
24.09
21.77
28.74
10.32
10.76
9.20
10.63
28.90
26.97
26.79
26.82
282.7
281.00
298.73
284.94
16.01
16.08
16.15
15.79
536.7
434.61
560.45
569.88
174.72
il 72.08
172.45
.179.88
135.66
138.50
130.73
137.48
61.63
60.14
61.55
63.36
age
SD
Control group
N = 102
groups
Mean
whole
0.01
.NS
NS
0.02
NS
NS
NS
NS
0.001
0:05
NS
0.10
iNS
iNS
iNS
0.001
0.02
0.001
0.10
0.001
0.001
0.001
NS
0.05
0.01
0.004
0.01
0.001
Significance
level fo r
Student’s t-test
su b-groups
124
B. Bazylewicz-Walczak et al.
Variaible
of
Significance
level
for
between
10.8
5.2
2.1
145.4
21
101.4
50.8
22.8
8.7
21.1
7.8**
26.4
403.8***
4***
568.9*
168.1
129.5
59.5
15.4*
593.8***
171.0
125.7**
60.1
25.8**
417.9***
19.6
7.1*
130.2
38.5
683.2*
4.1**
30.9
7.7
20.5
57.0***
Mean
* p < 0.0 5
** p<'0.01
*** p<0.001
37.6
19.6
137.1
32.3
11.7
1.1
6.3
25.8
SD
281.0
5.6
31.9
8.0
19.5
66.6***
Mean
the
2.0
109.8
27.6
21.2
7.4
3.6
139.6
11.6
6.7
39.6
41.1
203.2
5.1
9.7
1.3
6.9
19.1
SD
n=103
tests
n=51
psychological
E xposed
11— 15 years
on
E x p osed
5— 10 years
scores
653.9*
4.3*
average
Student’s t-test:
Digit S ym b ol
Digit Spain
Block Design
Bender Test
Kreapelin Test
e fficie n cy
% errors
Toulouse-Pieron Test
e ffic ie n cy
errors
Dots Location Test
e ffic ie n cy
errors
Simple Reaction Tim e
No. of correct responses
Mean reaction time (ms)
Complex Reaction Tim e
No. of correct responses
Mean reaction time (ms)
One-Plate Tapping
Two-Plate Tapping
Pegboard (time in s)
'Test
TABLE 3. Comparison
control g rou p
642.3**
3.9*
26.0***
7.5*
18.9*
66.9***
14.6***
608.2***
174.4
126.7*
61.4
25.6*
4S3.4***
17.4
8.7*
123.0
33.8
different
.
n=72
3.2
107.1
29.0
26.5
l.v
4.2
166.8
10.7
9.0
36.3
35.4
241.8
5.9
8.0
1.4
6.2
21.1
SD
E xposed
16— 30 years
of
Mean
groups
16.0
536.7
174.4
135.6
61.5
26.9
282.7
21.7
4.8
129.8
30.0
777.7
1.9
32.9
7.9
21.2
31.1
SD
and
1.3
86.5
28.4
25.3
10.3
0.6
68.0
12.3
4.9
27.8
22.2
246.8
2.3
9.1
1.1
6.2
20.6
Con1trols
duration
M ean
exposure
the
Psychologic effects of exposure to white spririt
125
i2G
B. Bazylewicz-Walczak et al.
plant, the concentrations of white spirit (according to the plant’s infor­
mation) considerably exceed the hygienic standard. Thus, workers ex­
posed for longer than 15 years may have been subject to more severe
intoxication. That is why the results obtained in this group can pro­
bably be attributed not only to exposure duration, but also to its mag­
nitude.
The set of variables, revealed in discriminant analysis as the one
best differentiating the exposed group from the unexposed should be
used for diagnosing the toxic effects of chronic exposure to white spirit.
This is, undoubtedly, very important for the early diagnosis of poiso­
nings, both in periodical medical examinations and in clinical examina­
tions for the purposes of medical certification. These variables have
included the following functions: correctness of perception and repro­
duction of visual material with particular attention paid to spatial
relationships, concentration, speed of reactions to single and complex
light stimuli, and manual dexterity.
The results obtained in our Study are concordant with the data from
literature concerning the effect of mixtures of solvents containing white
spirit. Thus, irrespective of procedures and test batteries applied, the
results obtained by others (7, 10) indicate a lowering of such functions
1as: manual dexterity, psychomotor coordination, concentration span and
time of reaction. Longer reaction times and lowered immediate memory
were found in the study of Gamberale et al. (5), whereas the deteriora­
tion of learning memory and abstraction functions were found in the
studies of Hanninen et al. (9), Elofasson et al. (4), Gregorsen et al. (6).
Finally, it should be stressed that the negative psychological
effects of .exposure to white spirit at concentrations close to* MAC would
suggest that the obligatory hygienic standards are not fully safe. Howe­
ver, this assumption calls for confirmation in the follow-up studies,
ensuring higher accuracy of conclusions due to the elimination of the
impact of individual differences on the obtained empirical material in
the compared groups.
Psychologic effects of exposure to white spririt
127
A C K N O W LE D G E M E N TS
The authors would like to thank Ms Krystyna Wojniłłowicz for her
technical assistance.
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