GALVANISING INDUSTRY: EVALUATION OF EXPOSURE LEVELS USING BIOMONITORS
Maria Ângela de B. C. Menezes* , Claudia de V. S. Sabino* , Angela M. Amaral* , Silvânia V. de M. Mattos**, Serafim
S. Filho***, Eugênio Diniz**** , Elene Cristina P. Maia*****
*
Centro de Desenvolvimento da Tecnologia Nuclear/CDTN
Comissão Nacional de Energia Nuclear/CNEN
[email protected], Caixa Postal 941
30123-970, Belo Horizonte, Minas Gerais, Brazil
**
FUNED, Divisão de Bromatologia e Toxicologia, Serviço de Química Especializada
Av. Conde Pereira Carneiro, 80, CEP 30550-010, Belo Horizonte, Minas Gerais, Brazil
***
Secretaria Municipal de Saúde de Belo Horizonte, Coordenação de Saúde do Trabalhador
Av. Afonso Pena, 2336, 4º andar, Funcionários, CEP 30130-007, Belo Horizonte, Minas Gerais, Brazil
****
Universidade Federal de Minas Gerais, Departamento de Química, Instituto de Ciências Exatas
Avenida Antonio Carlos, 6627, CEP 31270-901, Belo Horizonte, Minas Gerais , Brazil
ABSTRACT
In Brazil, statistical surveys concerning occupational diseases refer to accidents and damages.
The surveys do not refer to the occupational diseases developed through long exposures to hazardous
work conditions, involving physical risk and toxic chemical substances. The Program of Medical Control
of Occupational Health determines the Maximum Biological Levels Allowed and the Values of Normality
References. But concerning metal and toxic inorganics, values of only few elements are established. In
Belo Horizonte and surroundings areas, which is an important industrial centre in the country, there are
different industries distributed over various areas. There are about 80 galvanising industries which are
responsible for the majority of the metal contamination hospitalities.
A preliminary sampling was performed in order to conduct a survey of the exposures to elements
related to occupational diseases in galvanising industry. The preliminary results for toxic and non-toxic
elements obtained using hair and fingernails as biomonitors are shown. The k0 parametric neutron
activation analysis method was applied and the elements determined were: Ag, Al, Au, Cl, Co, Cr, Cu,
Fe, I, Mn, Na, Ti, V, Ta, and Zn.
Key Words: neutron activation; k0; biomonitor; occupational exposition; galvanising industry
I. INTRODUCTION
The
industrial
processes
introduce
the
contamination risks to the workers continually. The easiest
ones to be identified are those that kill or mutilate. Other
processes take time to produce the sinister effects, and
because of that contamination is difficult to be identified
[1]. There are nearly 15,000 chemical and physical toxic
agents commonly used in industries but there are only some
legal rules of exposition to about 5% of them. The effects
may appear in long-term. With more modern processes,
new chemical agents appear enlarging the list of pollutants
whose effects are yet unknown. Statistical surveys about
occupational diseases in Brazil refer to accidents and
damages and not to the occupational diseases developed
through long exposures to hazardous work conditions.
Documented cases refer only to dangerous conditions or
damages. The workplace exposures are registered when the
acquisition of disease is obvious or probable, that is,
dangerous diseases easily identified. The major problem is
that the great part of workers is exposed to low levels of
toxic chemicals, that can be lethal in a long period of time,
due to chronic diseases. Most often the outset of the
diseases goes unnoticed and the presence of a lung cancer
or heart diseases, medicinal groups and the industry itself
attribute them to non occupational causes. As result, these
diseases do not became part of the compiled data [1].
Among the toxic substances, there are metals
present in the environment that may cause from allergies to
cancer as well as dangerous intoxications. The Law n° 24
(29th December, 1994) from the Secretaria de Segurança e
Saúde no Trabalho (Security and Health at Work
Secretary), Brazil, approved the NR-7 Program of Medical
Control of Occupational Health [3], in which the Maximum
Biological Levels Allowed and the Values of Normality
References are established. Concerning metal and toxic
inorganics only the arsenic, chromium, cadmium, lead and
mercury values are established. Manganese, for instance,
which is not mentioned, presents a biological half-life of 37
days. This metal concentrates in brain and bones that
present the slowest rate of elimination [2]. No other metals
are mentioned.
The levels of exposure can be measured when
studying metals linked to occupational diseases using
biological monitors [4]. These bioindicators assess the
health risk through the evaluation of the level of
incorporation or exposure.
II. OBJECTIVE
This paper is about the preliminary evaluation of
exposure to metals in a galvanising industry with Pilot
Sampling using hair and nails as bioindicators. This work is
the first step of a project that will conduct a survey of
people who have been exposed to metals related to
occupational diseases and will examine which metals are
more critical in terms of exposure in the workplace.
III. STUDY AREA
Belo Horizonte, the capital of the State of Minas
Gerais, and surrounding areas, it is an important industrial
centre of Brazil, concentrating many industries in several
areas: metallurgy of iron, textile, automotive, refractory
materials, ink, food, mining, ceramics, and cement plants.
Considering the hazard involving chemical elements,
contamination by metals is a health hazard among workers
of different plants. However there are no records of the
level of metal concentration in the environmental air in
industry, not even any records of the level of contamination
of factory workers.
There are about 40 galvanising industries from those
called home industries to modern ones in Belo Horizonte.
Many of them are in the commercial centre of the city and
this kind of industry is responsible for the majority of metal
contamination occurrences.
The galvanising industry is an electroplating process
[5] where the process of depositing a coating having a
desirable form is by means of electrolysis. Its purpose is
generally to alter the characteristics of a surface so as to
provide an improved appearance, the ability to withstand
corrosive agents, resistance to abrasion, or other desired
properties or a combination of them although occasionally
it is used simply to alter dimensions. Electrolysis is carried
out in a bath which may consist of fused salts or solutions
of various kinds; in commercial practice it is almost
invariably a water solution. In general the steps in
galvanisation are: polishing using abrasives, washing with
acids and sodium hydroxide and electrodeposition
involving deposits of aluminium, cadmium, chromium,
cobalt, copper, gold, indium, iron, lead, nickel, platinum,
silver, tin and zinc.
IV. EXECUTION
Sampling. As it was mentioned aforesaid this research is
the fist step of a project, and the objective was just to have
an idea of the level of exposure of the workers. This Pilot
Sampling was carried out in small industry that was chosen
at random in downtown.
At first, the Physicians of the Secretaria Municipal
de Saúde (Municipal Department of Health) visited the
galvanising and explained the aims of the project and how
it would be performed.
In the next visit samples were collected. New
scissors was used and the collected material was
conditioned in plastics. The hair samples were collected
according to IAEA instructions [6].
Determination. The biomaterial were conditioned in the
polyethylene tubes after being weighted and without
washing. The objective of analysing without washing was
to verify the level of exposure.
It was applied the k0 parametric neutron activation
analysis [7,8] an instrumental and an absolute technique,
where the uncertain nuclear data were replaced by
compound nuclear constants – the k0 factors. The Högdahl
convention was used, where the concentration of the
element in the sample is calculated by means:
ma =
m p C n ,a ε p F p S p C a D a H a
k 0 C n , p ε a Fa S a C p D p H p
(1)
where
k0 =
M p θ a Pγ , a σ 0 , a
M a θ p Pγ , p σ 0 , p
(2)
Considering the subscript a , sample, and p standard,
in Eq. (1): m is the mass of the studying element; Cn is the
number of counts in the full-energy peak, corrected for
pulse losses (dead time, random and true coincidence); ε is
the full-energy peak detection efficiency, including
correction for gamma-attenuation; F is [f + Q0 (α)], where f
is the subcadmium to epithermal neutron flux ratio, and
Q0 (α) is the I0 (α ) , resonance integral, to σ0 , cross-section
thermal neutron, ratio, and α is the parameter describing
the real epithermal neutron flux distribution; S is the
saturation factor, function of irradiation time; C is the decay
factor during the counting; D is the decay factor between
irradiation and counting; H is the dead time during the
counting. In Eq. (2), k 0 is defined by: M, the molar mass; θ ,
the isotopic abundance; Py , the gamma - emission
probability; and σ , cross - section thermal neutron.
This is the k0 fundamental equation, the Högdahl
convention. For interesting 91 isotopes the k0 values have
been determined in several laboratories throughout the
world, and the k0 values are available in the bibliography
with uncertainty about 2%. For 21 elements the uncertainty
values are about 5%.
The irradiation was performed in the reactor TRIGA
MARK I IPR-R1 in the CDTN, that at 100 kW the neutron
flux is 6.6 x 1011 n.cm2 .s-1. The samples were irradiated
simultaneously accompanied by standards of Au and Na,
and Human Hair Reference Material. The elements were
determined through three schemes of irradiation: 5 min to
detect the short half-life; 4 hours to detect the medium, and
20 hours the long half-life radionuclides. After suitable
decay time, the gamma spectroscopy was performed in a
HPGe detector ORTEC, 10175-P, resolution of 1.85 keV in
the 1332 keV peak of 60 Co.
The Quality Control was done using replicates of
samples, when it was possible, and the Human Hair
Certificate Reference Material (GBW 09101), from
Shanghai Institute of Nuclear Research Academia Sinica.
3500
3000
2500
Polisher
1’s Hair
Hair
Polisher
1
2000
Human Hair
1500
1000
500
0
Al
Cl
Fe
Figure 1a. Elemental Concentration in Hair (from 0 to
3,500 µg.g-1)
V. CONCLUSION
The biomaterial samples were collected from 7
workers in a small industry: 2 officers, 2 bath operator, 1
metal piece washer and 2 polishers. It wasn’t possible,
during the sampling, to collect hair and fingernails from
everyone because of particular problems, for instance, the
Polisher 2 was bald, and the Officer 2, a women, had dyed
hair. The Piece Washer and the Officer 1 had cut their nails.
Because of the results are referred to a Pilot
Sampling, this evaluation is not conclusive but it is enough
to suppose the level of exposure of the workers in a
galvanising industry.
The TABLES I and II present the elemental
concentration determined in the biomonitors. The results
are in function of the occupation of the worker. At first
glance it is possible to verify that all the concentrations of
the elements in the worker’s hair are higher than in the
Human Hair Reference Material. The Polisher 1 presents
the worst situation: the concentration of Al is 3,420 µg.g-1
in hair sample while in Reference Material is 14 µg.g-1. In
this worker’s nail sample the Al concentration is 16,500
µg.g-1.
The Figures 1a, 1b, and 1c show the elemental
concentration in the Polisher 1’s hair compared to the
Human Hair Reference Material. Because fingernail
reference material was non existent, it was not possible to
compare the elemental concentrations. However the
determined concentrations in the samples suggest high
exposure.
600
500
Hair
Polisher
Polisher
1’s Hair
1
400
Human Hair
300
200
100
0
Cr
Cu
Mn
Na
Ti
Zn
Figure 1b. Elemental Concentration in Hair (from 0 to 600
µg.g-1)
2,5
Polisher
1’s 1Hair
Hair
Polisher
2
Human Hair
1,5
1
0,5
0
Ag
Au
Co
V
Ta
Figure 1c. Elemental Concentration in Hair (from 0 to 2.5
µg.g-1)
TABLE I. Elemental Concentration in Hair
(µg.g-1)
Officer 1
Zn Bath
Operator
Cr, Cu, Ni
Bath
Operator
Piece
washer
Polisher 1
Polisher 3
Ag
2.5 ± 0.2
0.60 ± 0.01
b
0.62 ± 0.09
2.6 ± 0.3
Al
485 ± 27
644 ± 45
134 ± 12
450 ± 20
3417 ± 67
Au
0.04 ± 0 01
0.011± 0.001
b
0.043± 0.002
Cl
1157 ± 150
1786 ± 387
942 ± 9
728 ± 90
1930 ± 200
Co
0.18 ± 0.06
a
b
0.15 ± 0.03
Cr
10.1 ± 0.2
6.6 ± 0.5
b
Cu
68 ± 33
116 ± 35
Fe
581 ± 29
I
HH*
HH*
experimental
values
certified
values
1.9 ± 0.1
a
0.35 c
538 ± 28
14 ± 7
13.3 ± 2.3
a
d
307 ± 80
157 ± 50
152 c
0.33 ± 0.07
0.44 ± 0.04
a
0.135±0.008
8.8 ± 0.3
14 ± 1
5.81 ± 0.03
4.6 ± 0.6
4.77 ± 0.38
82 ± 22
140 ± 23
400 ± 60
132 ± 30
19 ± 18
23 ± 1.4
124 ± 16
b
576 ± 28
1454 ± 73
860 ± 40
a
71.2 ± 6.6
5±2
a
a
a
a
a
a
0.875 c
Mn
9±4
a
5±3
6±3
22 ± 6
12 ± 3
4±2
2.94 ± 0.20
Na
758 ± 106
562 ± 122
a
478 ± 58
625 ± 100
610 ± 78
269 ± 48
266 ± 12
Ti
a
a
a
a
84 ± 40
a
a
d
V
a
a
a
a
2.1 ± 0.8
a
a
0.069 c
Zn
114 ± 2
125.55
b
135 ± 3
130 ± 5
103 ± 4
154 ± 8
189 ± 8
0.089± 0.005 0.232± 0.005
* Human Hair Reference Material
a , not detected; b, insufficient sample; c , information value; d, not determined
TABLE II. Elemental Concentration in Fingernail
(µg.g-1)
Officer 2
Zn Bath
Operator
Cr, Cu, Ni
Bath
Operator
Polisher 1
Polisher 2
Ag
b
a
a
12.9 ± 0.8
9± 1
Al
275 ± 100
776 ± 100
1540 ± 200
16500 ± 200
660 ± 190
Au
b
a
0.20 ± 0.03
0.37 ± 0.01
0.17 ± 0.04
Cl
2215 ± 650
457 ± 290
3420 ± 450
8770 ± 880
9130 ± 700
Co
b
a
2.5 ± 5
1.67 ± 0.02
2.36 ± 0.08
Cr
b
32 ± 5
530 ± 10
177 ± 2
75 ± 4
Cu
a
188 ± 96
1210 ± 135
990 ± 200
1040 ± 180
Fe
b
a
3430 ± 340
7527 ± 230
10690 ± 430
I
a
a
17 ± 8
a
a
Mn
a
a
14 ± 1
99 ± 20
a
Na
610 ± 380
1146 ± 258
1390 ± 340
2100 ± 500
1830 ± 380
Ti
a
a
a
210 ± 170
a
V
a
a
a
10 ± 4
2± 3
Ta
b
a
a
1.13 ± 0.01
a
Zn
b
954 ± 50
890 ± 44
672 ± 20
378 ± 23
a, not detected; b, insufficient sample
ACKNOWLEDGEMENTS
To International Atomic Energy Agency for the
collaboration and the research fund.
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