InternationalArchivesof
Occupaionalnd
Int Arch Occup Environ Health (1990) 62:7-10
Environmnental Health
Original articles
© Springer-Verlag 1990
Occupational chronic exposure to metals II Nickel exposure of stainless steel welders
biological monitoring*
J Angerer and G Lehnert Institute of Occupational and Social Medicine and Policlinic for Occupational Diseases, University of Erlangen-Nuremberg, Schillerstrasse 25/29, D-8520 Erlangen, Federal Republic of Germany Received June 30 / Accepted October 3, 1989
Summary Stainless steel welders (n = 103) were examined To estimate external exposure, personal air sampling was used Internal exposure was quantified by the determination of nickel levels in erythrocytes, plasma and urine Men and women (n = 123) were examined for control purposes In the plasma and erythrocytes of the controls the nickel concentration was below the level of detection (< 1 8 jtg/l) The element concentrations in urine were between < O1 and 13.3 jig/l Of the controls 95 % showed nickel levels in urine below 2 2 jg/l (reference value) The average concentration of nickel in the air was 93 + 81 g/m3 . The average concentration of nickel in the plasma samples was 4 9 + 4 0 jg/l (95th percentile 12 8 pg/l). In erythrocytes nickel could not be detected The nickel concentrations in the urine of the welders were 18.5 ± 28 5 pg/l on average ( 95th percentile 52 5 lg/l). Only a weak correlation between the nickel levels of plasma and urine could be detected (Curine = 2 07 + 8.45 Cplasma; r = 0 294; p < 0 01) Based on our results
and on the reported literature a future limit value for the nickel concentration in urine should lay between 30 and 50 pg/l This value corresponds to an external exposure of 500 Ag nickel per cubic metre. Key words: Nickel exposure Biological monitoring
Stainless steel welding -
Ambient monitoring
Limit
values
Introduction According to Stern et al ( 1986) in industrialized nations about 1% of occupationally working persons are engaged in the welding of metals The effects of welding to health is therefore of utmost importance. This is especially true for the welding of stainless * Dedicated to the 70th birthday of Professor Valentin Offprint requests to: J Angerer
steel where fumes and dusts are generated that contain nickel and chromium Grothe (1985) assumed that in the Federal Republic of Germany up to 30000 persons weld stainless steel Nickel and some of its compounds as well as several chromates have shown to be carcinogenic for men lDeutsche Forschungsgemeinschaft 1988 l Therefore it is of great importance for the prevention of occupational cancer to create means of estimating the internal exposure of carcinogenic substances with biological monitoring.
We determined the concentrations of nickel and chromium in the air of the working places as well as in erythrocytes, plasma and urine of stainless steel welders.
In this article we report our results concerning nickel The welders' chromium exposure have already been discussed lAngerer et al 1987 l It was one of our aims to collect data for a future evaluation of limit values for biological monitoring data. Materials and methods Male welders (n = 103) of chromium-nickel alloyed steel (18 % Cr; 10 % Ni; 6-8 % Mn) were investigated as to their external and internal exposure to nickel The workers were employed in a shipbuilding yard, where among others, special vehicles
are built The welders were between 20 5 and 55 9-years-old (x = 37 9 + 9 7) They had been employed in this firm for between 0 3 and 25 0 years ( = 9 5 + 7 1). Employees (n = 39) welded with coated electrodes (MMA). Fourteen workers did metal inert gas (MIG) welding only and 50 welders used the MMA as well as the MIG welding method. A group of 123 men and women occupationally not exposed to nickel was examined for control purposes. External exposure was estimated by personal air monitoring of the concentration of nickel in the air The sampling filters were placed inside the welders' face masks in the breathing zone The sampling intervals ranged between 1 85 and 5 20 h. Internal exposure was estimated by the levels of nickel in erythrocytes, plasma and urine. The biological specimens were taken at the end of an 8-h shift after at least three consecutive exposure periods Blood samples were taken from the cubital vein using EDTA-coated
8
J Angerer and G Lehnert: Nickel exposure of stainless steel welders
syringes The samples were immediately shipped to the laboratory where plasma and erythrocytes were gained after centrifugation Spot urine samples were taken at the end of the shift using polyethylene bottles Until the time of analysis all vessels containing biological specimens were stored at 18°C. The filters were analyzed for their nickel content after wet ashing with nitric and hydrochloric acid, using flame atomic absorption lHauptverband der gewerblichen Berufsgenossenschaften 1983 l. Nickel levels in erythrocytes and plasma were determined using electrothermal atomic absorption spectrometry Blood samples (2 5 ml EDTA) were centrifuged to separate erythrocytes from plasma Before further preparation erythrocytes were washed with sodium chloride solution (0 9 %) six times. For AAS-determination erythrocytes and plasma were diluted sevenfold using 0 01% Triton-X-100 solution For the mineralization of the biological matrix a three-step temperature program (350° , 500° and 1000°C) was used lAngerer et al 1988al. The detection limit was 1 8 tgl. Nickel concentrations in urine were also determined with ETAAS A very sensitive chelatization extraction procedure was used for clean-up and enrichment (Angerer et al 1985). The detection limit was O 1 gg/1. Statistics were gathered according to the rules normally used in medicine and toxicology.
a
._
.0
1 13 3 jg/I
-2
E
0.01
0 05 O1
05 1 O 5O 0.6 22
nickel in urine pg/I
Fig 1 Cumulative distribution of nickel concentrations in urine samples of 123 occupationally unexposed persons (Fig 1)
urine
0
.5 .0 Mn
Results and discussion In plasma and erythrocytes of the control group nickel could not be detected, which means that the nickel levels in these compartments were below the detection limit of 1 8 ltg/l This is in accordance with the literature of the past years where reference values below 2 Ojtg/l were reported The nickel concentrations in the urine samples of the controls showed values between not detectable (< O1 tg/1) and 13 3 ltg/l. Of all values 50% were below 0 6 g/l Of the controls 95% had nickel urine levels below 2 2 gg/I (Fig 1) These values agree well with other reports in the literature Reference values for nickel in blood and urine have been compiled lately lAngerer et al. 1988 bl. Personal air monitoring of MMA welders showed concentrations in the air between < 50 g and 260 jtg nickel per cubic metre ( = 72 ± 82 lg/m 3; N = 9). MIG welders were exposed to somewhat higher concentrations The values ranged from between < 50 Vlg and 320 gg nickel per cubic metre (X = 100 + 82 gg/m 3 ;
n = 26) The average for all (n = 35) measurement of the nickel concentrations in the air was 93 + 81 4 gg/ m3 Median values and 95th percentiles were 60 and 260 Lg/m 3, respectively This means that all values measured in the air were well below the German Technical Guiding Concentration (TRK) of 500 gg/m3 lDeutsche Forschungsgemeinschaft 1988l, which is evaluated for the concentration of nickel and its less soluble compounds in the air of the work places. In none of the welders' blood samples could nickel be detected in erythrocytes The detection limit of
.5 E
nickel concentration
U
0.1
05 1 O
39
12 8
10.2
2100
52.5
pg/I
Fig 2 Cumulative distribution of nickel concentrations in plasma and urine samples of 103 stainless steel welders (Fig 2)
this method is 1 8 lg/l, which means that nickel, absorbed via inhalation of welding fumes, is not able to penetrate cell membranes on a greater scale. Whereas nickel could not be detected in erythrocytes, 82 of 103 welders had measurable nickel concentrations in plasma The plasma levels of nickel were up to 19 6 ltg/l Compared with reference values in the order of 1 g/l lRaithel et al 1985 ; Drazniowsky et al 1985 ; Andersen et al 1986l, the plasma levels of the welders were up to 20 times higher Median and 95th percentile of the welders' nickel levels in plasma were 3 9 and 12 8 pg/l (Fig 2) The average nickel concentrations in plasma samples of those welders using both welding methods seem to be a little bit higher than that of the workers using MMA or MIG, respectively (Table 1). The nickel concentrations in the urine samples of all welders ranged from between 0 1 and 209 4 gg/l. The median value and the 95th percentile were 10 2 and 52 5 jtg/, respectively Comparing these results with those of the control group the nickel urine levels of the welders were, as in the case of plasma, in the order of about 20 times higher than that of occupationally unexposed persons (Fig 2 ; Table 1).
J Angerer and G Lehnert: Nickel exposure of stainless steel welders Table 1 Concentrations of nickel in plasma and urine of manual metal arc (MMA), metal inert gas (MIG), welders using both methods (MMA, MIG) and controls in gg/l. n: number of persons investigated; x: mean; SD: standard deviation; m: median n
Plasma x+SD;m (range)
MMA
39
MIG
14
MMA, MIG
50
43 3 9 ;2 8 (< 1 8 18 1) 3 9 ± 4 4; 2 7 (< 1 8 14 6) 5 6+ 4 1 ; 4 8 (< 1 8 19 6) 4 9 + 4 O; 3 9 (< 1 8 19 6)
Occupaionalnd
Int Arch Occup Environ Health (1990) 62:7-10
Environmnental Health
Original articles
© Springer-Verlag 1990
Occupational chronic exposure to metals II Nickel exposure of stainless steel welders
biological monitoring*
J Angerer and G Lehnert Institute of Occupational and Social Medicine and Policlinic for Occupational Diseases, University of Erlangen-Nuremberg, Schillerstrasse 25/29, D-8520 Erlangen, Federal Republic of Germany Received June 30 / Accepted October 3, 1989
Summary Stainless steel welders (n = 103) were examined To estimate external exposure, personal air sampling was used Internal exposure was quantified by the determination of nickel levels in erythrocytes, plasma and urine Men and women (n = 123) were examined for control purposes In the plasma and erythrocytes of the controls the nickel concentration was below the level of detection (< 1 8 jtg/l) The element concentrations in urine were between < O1 and 13.3 jig/l Of the controls 95 % showed nickel levels in urine below 2 2 jg/l (reference value) The average concentration of nickel in the air was 93 + 81 g/m3 . The average concentration of nickel in the plasma samples was 4 9 + 4 0 jg/l (95th percentile 12 8 pg/l). In erythrocytes nickel could not be detected The nickel concentrations in the urine of the welders were 18.5 ± 28 5 pg/l on average ( 95th percentile 52 5 lg/l). Only a weak correlation between the nickel levels of plasma and urine could be detected (Curine = 2 07 + 8.45 Cplasma; r = 0 294; p < 0 01) Based on our results
and on the reported literature a future limit value for the nickel concentration in urine should lay between 30 and 50 pg/l This value corresponds to an external exposure of 500 Ag nickel per cubic metre. Key words: Nickel exposure Biological monitoring
Stainless steel welding -
Ambient monitoring
Limit
values
Introduction According to Stern et al ( 1986) in industrialized nations about 1% of occupationally working persons are engaged in the welding of metals The effects of welding to health is therefore of utmost importance. This is especially true for the welding of stainless * Dedicated to the 70th birthday of Professor Valentin Offprint requests to: J Angerer
steel where fumes and dusts are generated that contain nickel and chromium Grothe (1985) assumed that in the Federal Republic of Germany up to 30000 persons weld stainless steel Nickel and some of its compounds as well as several chromates have shown to be carcinogenic for men lDeutsche Forschungsgemeinschaft 1988 l Therefore it is of great importance for the prevention of occupational cancer to create means of estimating the internal exposure of carcinogenic substances with biological monitoring.
We determined the concentrations of nickel and chromium in the air of the working places as well as in erythrocytes, plasma and urine of stainless steel welders.
In this article we report our results concerning nickel The welders' chromium exposure have already been discussed lAngerer et al 1987 l It was one of our aims to collect data for a future evaluation of limit values for biological monitoring data. Materials and methods Male welders (n = 103) of chromium-nickel alloyed steel (18 % Cr; 10 % Ni; 6-8 % Mn) were investigated as to their external and internal exposure to nickel The workers were employed in a shipbuilding yard, where among others, special vehicles
are built The welders were between 20 5 and 55 9-years-old (x = 37 9 + 9 7) They had been employed in this firm for between 0 3 and 25 0 years ( = 9 5 + 7 1). Employees (n = 39) welded with coated electrodes (MMA). Fourteen workers did metal inert gas (MIG) welding only and 50 welders used the MMA as well as the MIG welding method. A group of 123 men and women occupationally not exposed to nickel was examined for control purposes. External exposure was estimated by personal air monitoring of the concentration of nickel in the air The sampling filters were placed inside the welders' face masks in the breathing zone The sampling intervals ranged between 1 85 and 5 20 h. Internal exposure was estimated by the levels of nickel in erythrocytes, plasma and urine. The biological specimens were taken at the end of an 8-h shift after at least three consecutive exposure periods Blood samples were taken from the cubital vein using EDTA-coated
8
J Angerer and G Lehnert: Nickel exposure of stainless steel welders
syringes The samples were immediately shipped to the laboratory where plasma and erythrocytes were gained after centrifugation Spot urine samples were taken at the end of the shift using polyethylene bottles Until the time of analysis all vessels containing biological specimens were stored at 18°C. The filters were analyzed for their nickel content after wet ashing with nitric and hydrochloric acid, using flame atomic absorption lHauptverband der gewerblichen Berufsgenossenschaften 1983 l. Nickel levels in erythrocytes and plasma were determined using electrothermal atomic absorption spectrometry Blood samples (2 5 ml EDTA) were centrifuged to separate erythrocytes from plasma Before further preparation erythrocytes were washed with sodium chloride solution (0 9 %) six times. For AAS-determination erythrocytes and plasma were diluted sevenfold using 0 01% Triton-X-100 solution For the mineralization of the biological matrix a three-step temperature program (350° , 500° and 1000°C) was used lAngerer et al 1988al. The detection limit was 1 8 tgl. Nickel concentrations in urine were also determined with ETAAS A very sensitive chelatization extraction procedure was used for clean-up and enrichment (Angerer et al 1985). The detection limit was O 1 gg/1. Statistics were gathered according to the rules normally used in medicine and toxicology.
a
._
.0
1 13 3 jg/I
-2
E
0.01
0 05 O1
05 1 O 5O 0.6 22
nickel in urine pg/I
Fig 1 Cumulative distribution of nickel concentrations in urine samples of 123 occupationally unexposed persons (Fig 1)
urine
0
.5 .0 Mn
Results and discussion In plasma and erythrocytes of the control group nickel could not be detected, which means that the nickel levels in these compartments were below the detection limit of 1 8 ltg/l This is in accordance with the literature of the past years where reference values below 2 Ojtg/l were reported The nickel concentrations in the urine samples of the controls showed values between not detectable (< O1 tg/1) and 13 3 ltg/l. Of all values 50% were below 0 6 g/l Of the controls 95% had nickel urine levels below 2 2 gg/I (Fig 1) These values agree well with other reports in the literature Reference values for nickel in blood and urine have been compiled lately lAngerer et al. 1988 bl. Personal air monitoring of MMA welders showed concentrations in the air between < 50 g and 260 jtg nickel per cubic metre ( = 72 ± 82 lg/m 3; N = 9). MIG welders were exposed to somewhat higher concentrations The values ranged from between < 50 Vlg and 320 gg nickel per cubic metre (X = 100 + 82 gg/m 3 ;
n = 26) The average for all (n = 35) measurement of the nickel concentrations in the air was 93 + 81 4 gg/ m3 Median values and 95th percentiles were 60 and 260 Lg/m 3, respectively This means that all values measured in the air were well below the German Technical Guiding Concentration (TRK) of 500 gg/m3 lDeutsche Forschungsgemeinschaft 1988l, which is evaluated for the concentration of nickel and its less soluble compounds in the air of the work places. In none of the welders' blood samples could nickel be detected in erythrocytes The detection limit of
.5 E
nickel concentration
U
0.1
05 1 O
39
12 8
10.2
2100
52.5
pg/I
Fig 2 Cumulative distribution of nickel concentrations in plasma and urine samples of 103 stainless steel welders (Fig 2)
this method is 1 8 lg/l, which means that nickel, absorbed via inhalation of welding fumes, is not able to penetrate cell membranes on a greater scale. Whereas nickel could not be detected in erythrocytes, 82 of 103 welders had measurable nickel concentrations in plasma The plasma levels of nickel were up to 19 6 ltg/l Compared with reference values in the order of 1 g/l lRaithel et al 1985 ; Drazniowsky et al 1985 ; Andersen et al 1986l, the plasma levels of the welders were up to 20 times higher Median and 95th percentile of the welders' nickel levels in plasma were 3 9 and 12 8 pg/l (Fig 2) The average nickel concentrations in plasma samples of those welders using both welding methods seem to be a little bit higher than that of the workers using MMA or MIG, respectively (Table 1). The nickel concentrations in the urine samples of all welders ranged from between 0 1 and 209 4 gg/l. The median value and the 95th percentile were 10 2 and 52 5 jtg/, respectively Comparing these results with those of the control group the nickel urine levels of the welders were, as in the case of plasma, in the order of about 20 times higher than that of occupationally unexposed persons (Fig 2 ; Table 1).
J Angerer and G Lehnert: Nickel exposure of stainless steel welders Table 1 Concentrations of nickel in plasma and urine of manual metal arc (MMA), metal inert gas (MIG), welders using both methods (MMA, MIG) and controls in gg/l. n: number of persons investigated; x: mean; SD: standard deviation; m: median n
Plasma x+SD;m (range)
MMA
39
MIG
14
MMA, MIG
50
43 3 9 ;2 8 (< 1 8 18 1) 3 9 ± 4 4; 2 7 (< 1 8 14 6) 5 6+ 4 1 ; 4 8 (< 1 8 19 6) 4 9 + 4 O; 3 9 (< 1 8 19 6)
