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International Archives of
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Environmental Health © Springer-Verlag 1992 Internal exposure to organic substances in a municipal waste incinerator J.Angerer l , B Heinzow 2 , D O Reimann3 , W Knorz 4 , and G Lehnertl 1Institut ftir Arbeits und Sozialmedizin der Universitit, Schillerstrasse 25/29, W-8520 Erlangen-Niirnberg, Federal Republic of Germany 2 Umwelttoxikologische Untersuchungsstelle des Landes Schleswig Holstein, Kiel, Federal Republic of Germany 3 Zweckverband Miillheizkraftwerk, Bamberg, Federal Republic of Germany 4 Berufsgenossenschaftlicher Arbeitsmedizinischer Dienst, Lichtenfels, Federal Republic of Germany Received June 2 / Accepted July 9, 1992
Summary Fifty-three persons occupied in a municipal waste incinerator were examined with respect to their internal exposure to organic substances which may be produced during pyrolysis of organic matter For this purpose the levels of benzene in blood, polychlorinated biphenyls (PC Bs) and hexachlorobenzene (HCB) in plasma, and mono (MC Ps), di (DC Ps), tri (TC Ps), tetra(TEC Ps) and pentachlorophenol (PCP) and hydroxypyrene in urine were determined For control purposes, 431 men and women were examined Significantly higher values for the workers were found for the excretion of hydroxypyrene lmedian (m): 0 24 vs O 11 pg/l; non-smokersl, 2,4/2,5-DCP (m: 10 5 vs 3 91pg/l) and 2,4,5-TCP (m: 1 2 vs 0 8 pg/l) and for the HCB level in plasma (m: 4.4 vs 2 8 lg/l) For the concentrations of 4-MCP and 2,3,4,6/2,3,5,6-TECP, the controls had significantly higher concentrations in urine than did the workers in the incineration plant (m: 4-MCP 1 7vs 1 2 ; 2,3,4,6/2,3,5,6-TECP: 1.2 vs 0 3 pg/l) No significant differences between workers and controls were detected with respect to benzene in blood (m: 0 20 vs 0 28 pg/l; non-smokers), 2,4,6-TCP and PCPs in urine (m: 0 85 vs 0 60 and 2 2 vs 2 2 pg/l) or 138, 153, the levels of PCB congeners in plasma (m: 180: 5 6 vs 4 1 pg/1) The elevated levels of hydroxypyrene, 2,4/2,5-DCP, 2,4,5-TCP and HCB in biological material may be related to the incineration of the waste. These elevations, however, are very small and are of interest more from the environmental than from the occupational point of view. Benzene Key words: Municipal waste incinerator Polychlorinated biphenyls Hydroxypyrene Hexachlorobenzene Chlorophenols
Introduction Waste incinerators and their emissions of hazardous chemical substances are of great public concern The poCorrespondenceto: J Angerer
tential risks to the health of the population have recently been evaluated (Greim and Link 1989; Bolt et al 1990 ; Hahn and Sofaer 1991) In this context the exposure of employees working inside an incinerator is surely a matter of interest Within the scope of our role in the health supervision of occupationally exposed persons we had the opportunity to examine the entire staff of such a plant Since the exposure to anorganic substances had formerly been estimated, we concentrated on the internal exposure to organic substances generated during the pyrolysis of organic matter. Materials and methods Fifty-three persons, 3 women and 50 men, working in a municipal waste incinerator (MWI) were examined for internal exposure to those organic substances generated during the pyrolysis of waste. The workers were between 22 and 52 years old and had been employed in this plant for between 0 5 and 14 years Among the garbage from households and industry, solvents, plastics, waste oil, savage sludge etc are burned There is no separation of the material before incineration In three furnaces 135000 tonnes of waste are burned per year The temperature, between 800 ° and 1000 °C, is regulated by blowing air through the furnaces After passing an electrostatic filter, the flue gases are washed with hydrochloric acid and soda lye The resulting sludge after centrifugation is refused together with the filter dust All persons examined should have been more or less equally exposed to possibly hazardous substances because most of them took it in turns to fulfil the same functions The exposure to hazardous substances should be highest during the maintenance and cleaning of the furnaces (necessary at least once a month) and during the maintenance of electrostatic filters. Internal exposure was measured by the concentrations of benzene in blood, of polychlorinated biphenyls (PC Bs) and hexachlorobenzene (HCB) in plasma and of chlorophenols and hydroxypyrene in urine For this purpose, blood samples were taken after three work shifts The first morning urine of the same day served for the determination of chlorophenols and hydroxypyrene. For reference purposes 431 men and women who belong to different subgroups mainly living in Schleswig-Holstein and Franconia, Germany, were examined for the same parameters as the group of workers in the incineration plant These persons, who were healthy and between 18 and 84 years old, had no known occupational contact to those substances which are thought to be produced in garbage incineration There was no specific time when
266 blood and spot urine sampels were taken Unless otherwise stated in the text, the results for the toxicological parameters in the control group did not differ with respect to sex, age, weight, Broca index, smoking habits or place of residence. For the determination of benzene in blood a dynamic head space capillary gas chromatographic method with flame ionisation detection was used The volatile organic compounds were purged from incubated blood vials with nitrogen and enriched on a cooled trap filled with tenax After flush heating of the trap, benzene was separated on a fused silica capillary column (Angerer et al 1991). The concentration of hydroxypyrene in urine was determined using high pressure liquid chromatography and fluroescence detection For clean-up 1-hydroxypyrene was enzymatically released from its conjugates The analyte was then separated from the urine matrix by liquid solid extraction on a reversed phase column. PC Bs and HCB were analysed in plasma using a method of the MAK Commission of the Deutsche Forschungsgemeinschaft 1991 (Angerer and Schaller 1991) After homogenisation with formic acid, the plasma was extracted with n-heptane containing 2 2 ', 6 6 'tetrachlorobiphenyl and mirex as internal standard The organic layer was then passed over a silica gel column where lipids were removed The cleansed organic phase was concentrated and analysed by means of capillary gas chromatography and an electron capture detector From the numerous PCB congeners according to Beck and Mathar (1985), six (28, 52, 101, 138, 153, 180) (Ballschmiter 1988) characteristic for the internal exposure were analysed. Mono (MC Ps), di-(DCPs), tri (TC Ps) and tetra-chlorophenols (TECPs) were determined after acid hydrolysis and steam distillation of the urine, which was spiked with 2,6-dibromophenol as internal standard The distillate was then passed through a cation exchange column and a reversed phase column where the chlorophenols were concentrated After elution with n-heptane the chlorophenols were derivatised with diazomethane and analysed by capillary gas chromatography/mass spectrometry This method is a slight modification of the procedure which we have published recently (Angerer et al 1992). Pentachlorophenol was analysed in urine according to a method of the MAK Commission of the DFG (Deutsche Forschungsgemeinschaft 1981), modified with respect to the gas chromatographic column and the derivatisation procedure After acid hydrolysis, urine was extracted with diethylether Diazomethane was used for derivatisation Pentachlorophenol was then analysed by means of capillary gas chromatography and electron capture detection. Statistical methods Linear correlations were performed by the method of least squares fit Differences between sets of values of possibly exposed workers and the normal population were tested according to the non-parametric U-test of Wilcoxon, Mann and Whitney (Ostle 1963).
Results and discussion It was the aim of this study to estimate the possible internal exposure of workers in an MWI to organic substances. From all substances which may occur in such a plant, we chose to investigate those which are formed under conditions of pyrolysis of organic matter Figure 1 shows a simplified scheme of reactions which take place in every process where organic material is burned and where chlorine or chlorine compounds are present (Ballschmiter 1991) Under these conditions benzene, a known human carcinogen, is a major product Benzene is the starting material for the formation of polyaromatic hydrocarbons (PAHs) Many substances from this group of PAHs are carcinogenic for humans or animals On the other hand in the presence of chlorine or chlorine compounds, chlorobenzenes are produced under pyrolytic conditions.
Fig 1 Principal routes of reactions which take place whenever organic material is burned or pyrolysed and when chlorine is present in any form (Simplified according to Ballschmiter 1991)
Chlorobenzenes like HCB give rise to the formation of chlorophenols and PC Bs On account of their effects on liver, enzymes and the immune system, PCBs are important substances in the field of occupational and environmental health The formation of chlorophenols and PCBs is the conditio sine qua non for the production of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) These substances, which are thought to be among the most toxic to mankind, are those which attract the most interest in the public discussion on waste incineration. Bearing this in mind, we decided to estimate the internal exposure of MWI workers on the basis of the following parameters: 1 Benzene level in blood In diagnostic and analytical terms, this is the most sensitive and specific parameter for benzene exposure. 2 Concentration of hydroxypyrene in urine Hydroxypyrene is a metabolite of pyrene and has been shown to be a good indicator of internal exposure to PAH (Jongeneelen et al 1986 ; Jongeneelen and Anzion 1991; Tolos et al 1990). 3 PCBs and HCB in plasma and chlorophenols in urine were determined mainly because they are precursors of PCD Ds and PCD Fs It has been reported that the concentration of PC Bs is closely related to levels of PCDDs/PCD Fs (Ballschmiter 1991), PCB levels being 25000-fold higher than those of PCDDs/PCDFs Because the determination of PC Bs, HCB and chlorophenols is much less difficult and expensive than the analysis of PCD Ds/PCDFs in biological material, the former might be good indicators of exposure to chlorinated dioxins and furans Moreover, PC Bs, HCB and chlorophenols themselves are important parameters from an occupational and environmental point of view. Benzene in blood The employees and 93 men and women with no occupational contact to benzene were examined for their blood benzene level Because smoking of tobacco is a prominent source of internal benzene exposure, both groups were subdivided according to their smoking habits The results of our examinations are presented in Table 1 No
267 Table 1 Concentrations of benzene in venous blood samples of MWI workers and of occupationally unexposed controls All concentrations are presented in Lg/l
N
+SD
17
0 459 ± 0 222 (0.370 ;
0.170
0 860 36
(0.195 ; 0 395)
t-N
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,Ut
T 7-;
Trr1
lLJ IlVIUII
1 Il
41, (~10011 AA l O Lll l
l 1);L 16
'r
Ar_')'71 6
g-l,
International Archives of
J
OCe Upatlionalnd
Environmental Health © Springer-Verlag 1992 Internal exposure to organic substances in a municipal waste incinerator J.Angerer l , B Heinzow 2 , D O Reimann3 , W Knorz 4 , and G Lehnertl 1Institut ftir Arbeits und Sozialmedizin der Universitit, Schillerstrasse 25/29, W-8520 Erlangen-Niirnberg, Federal Republic of Germany 2 Umwelttoxikologische Untersuchungsstelle des Landes Schleswig Holstein, Kiel, Federal Republic of Germany 3 Zweckverband Miillheizkraftwerk, Bamberg, Federal Republic of Germany 4 Berufsgenossenschaftlicher Arbeitsmedizinischer Dienst, Lichtenfels, Federal Republic of Germany Received June 2 / Accepted July 9, 1992
Summary Fifty-three persons occupied in a municipal waste incinerator were examined with respect to their internal exposure to organic substances which may be produced during pyrolysis of organic matter For this purpose the levels of benzene in blood, polychlorinated biphenyls (PC Bs) and hexachlorobenzene (HCB) in plasma, and mono (MC Ps), di (DC Ps), tri (TC Ps), tetra(TEC Ps) and pentachlorophenol (PCP) and hydroxypyrene in urine were determined For control purposes, 431 men and women were examined Significantly higher values for the workers were found for the excretion of hydroxypyrene lmedian (m): 0 24 vs O 11 pg/l; non-smokersl, 2,4/2,5-DCP (m: 10 5 vs 3 91pg/l) and 2,4,5-TCP (m: 1 2 vs 0 8 pg/l) and for the HCB level in plasma (m: 4.4 vs 2 8 lg/l) For the concentrations of 4-MCP and 2,3,4,6/2,3,5,6-TECP, the controls had significantly higher concentrations in urine than did the workers in the incineration plant (m: 4-MCP 1 7vs 1 2 ; 2,3,4,6/2,3,5,6-TECP: 1.2 vs 0 3 pg/l) No significant differences between workers and controls were detected with respect to benzene in blood (m: 0 20 vs 0 28 pg/l; non-smokers), 2,4,6-TCP and PCPs in urine (m: 0 85 vs 0 60 and 2 2 vs 2 2 pg/l) or 138, 153, the levels of PCB congeners in plasma (m: 180: 5 6 vs 4 1 pg/1) The elevated levels of hydroxypyrene, 2,4/2,5-DCP, 2,4,5-TCP and HCB in biological material may be related to the incineration of the waste. These elevations, however, are very small and are of interest more from the environmental than from the occupational point of view. Benzene Key words: Municipal waste incinerator Polychlorinated biphenyls Hydroxypyrene Hexachlorobenzene Chlorophenols
Introduction Waste incinerators and their emissions of hazardous chemical substances are of great public concern The poCorrespondenceto: J Angerer
tential risks to the health of the population have recently been evaluated (Greim and Link 1989; Bolt et al 1990 ; Hahn and Sofaer 1991) In this context the exposure of employees working inside an incinerator is surely a matter of interest Within the scope of our role in the health supervision of occupationally exposed persons we had the opportunity to examine the entire staff of such a plant Since the exposure to anorganic substances had formerly been estimated, we concentrated on the internal exposure to organic substances generated during the pyrolysis of organic matter. Materials and methods Fifty-three persons, 3 women and 50 men, working in a municipal waste incinerator (MWI) were examined for internal exposure to those organic substances generated during the pyrolysis of waste. The workers were between 22 and 52 years old and had been employed in this plant for between 0 5 and 14 years Among the garbage from households and industry, solvents, plastics, waste oil, savage sludge etc are burned There is no separation of the material before incineration In three furnaces 135000 tonnes of waste are burned per year The temperature, between 800 ° and 1000 °C, is regulated by blowing air through the furnaces After passing an electrostatic filter, the flue gases are washed with hydrochloric acid and soda lye The resulting sludge after centrifugation is refused together with the filter dust All persons examined should have been more or less equally exposed to possibly hazardous substances because most of them took it in turns to fulfil the same functions The exposure to hazardous substances should be highest during the maintenance and cleaning of the furnaces (necessary at least once a month) and during the maintenance of electrostatic filters. Internal exposure was measured by the concentrations of benzene in blood, of polychlorinated biphenyls (PC Bs) and hexachlorobenzene (HCB) in plasma and of chlorophenols and hydroxypyrene in urine For this purpose, blood samples were taken after three work shifts The first morning urine of the same day served for the determination of chlorophenols and hydroxypyrene. For reference purposes 431 men and women who belong to different subgroups mainly living in Schleswig-Holstein and Franconia, Germany, were examined for the same parameters as the group of workers in the incineration plant These persons, who were healthy and between 18 and 84 years old, had no known occupational contact to those substances which are thought to be produced in garbage incineration There was no specific time when
266 blood and spot urine sampels were taken Unless otherwise stated in the text, the results for the toxicological parameters in the control group did not differ with respect to sex, age, weight, Broca index, smoking habits or place of residence. For the determination of benzene in blood a dynamic head space capillary gas chromatographic method with flame ionisation detection was used The volatile organic compounds were purged from incubated blood vials with nitrogen and enriched on a cooled trap filled with tenax After flush heating of the trap, benzene was separated on a fused silica capillary column (Angerer et al 1991). The concentration of hydroxypyrene in urine was determined using high pressure liquid chromatography and fluroescence detection For clean-up 1-hydroxypyrene was enzymatically released from its conjugates The analyte was then separated from the urine matrix by liquid solid extraction on a reversed phase column. PC Bs and HCB were analysed in plasma using a method of the MAK Commission of the Deutsche Forschungsgemeinschaft 1991 (Angerer and Schaller 1991) After homogenisation with formic acid, the plasma was extracted with n-heptane containing 2 2 ', 6 6 'tetrachlorobiphenyl and mirex as internal standard The organic layer was then passed over a silica gel column where lipids were removed The cleansed organic phase was concentrated and analysed by means of capillary gas chromatography and an electron capture detector From the numerous PCB congeners according to Beck and Mathar (1985), six (28, 52, 101, 138, 153, 180) (Ballschmiter 1988) characteristic for the internal exposure were analysed. Mono (MC Ps), di-(DCPs), tri (TC Ps) and tetra-chlorophenols (TECPs) were determined after acid hydrolysis and steam distillation of the urine, which was spiked with 2,6-dibromophenol as internal standard The distillate was then passed through a cation exchange column and a reversed phase column where the chlorophenols were concentrated After elution with n-heptane the chlorophenols were derivatised with diazomethane and analysed by capillary gas chromatography/mass spectrometry This method is a slight modification of the procedure which we have published recently (Angerer et al 1992). Pentachlorophenol was analysed in urine according to a method of the MAK Commission of the DFG (Deutsche Forschungsgemeinschaft 1981), modified with respect to the gas chromatographic column and the derivatisation procedure After acid hydrolysis, urine was extracted with diethylether Diazomethane was used for derivatisation Pentachlorophenol was then analysed by means of capillary gas chromatography and electron capture detection. Statistical methods Linear correlations were performed by the method of least squares fit Differences between sets of values of possibly exposed workers and the normal population were tested according to the non-parametric U-test of Wilcoxon, Mann and Whitney (Ostle 1963).
Results and discussion It was the aim of this study to estimate the possible internal exposure of workers in an MWI to organic substances. From all substances which may occur in such a plant, we chose to investigate those which are formed under conditions of pyrolysis of organic matter Figure 1 shows a simplified scheme of reactions which take place in every process where organic material is burned and where chlorine or chlorine compounds are present (Ballschmiter 1991) Under these conditions benzene, a known human carcinogen, is a major product Benzene is the starting material for the formation of polyaromatic hydrocarbons (PAHs) Many substances from this group of PAHs are carcinogenic for humans or animals On the other hand in the presence of chlorine or chlorine compounds, chlorobenzenes are produced under pyrolytic conditions.
Fig 1 Principal routes of reactions which take place whenever organic material is burned or pyrolysed and when chlorine is present in any form (Simplified according to Ballschmiter 1991)
Chlorobenzenes like HCB give rise to the formation of chlorophenols and PC Bs On account of their effects on liver, enzymes and the immune system, PCBs are important substances in the field of occupational and environmental health The formation of chlorophenols and PCBs is the conditio sine qua non for the production of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) These substances, which are thought to be among the most toxic to mankind, are those which attract the most interest in the public discussion on waste incineration. Bearing this in mind, we decided to estimate the internal exposure of MWI workers on the basis of the following parameters: 1 Benzene level in blood In diagnostic and analytical terms, this is the most sensitive and specific parameter for benzene exposure. 2 Concentration of hydroxypyrene in urine Hydroxypyrene is a metabolite of pyrene and has been shown to be a good indicator of internal exposure to PAH (Jongeneelen et al 1986 ; Jongeneelen and Anzion 1991; Tolos et al 1990). 3 PCBs and HCB in plasma and chlorophenols in urine were determined mainly because they are precursors of PCD Ds and PCD Fs It has been reported that the concentration of PC Bs is closely related to levels of PCDDs/PCD Fs (Ballschmiter 1991), PCB levels being 25000-fold higher than those of PCDDs/PCDFs Because the determination of PC Bs, HCB and chlorophenols is much less difficult and expensive than the analysis of PCD Ds/PCDFs in biological material, the former might be good indicators of exposure to chlorinated dioxins and furans Moreover, PC Bs, HCB and chlorophenols themselves are important parameters from an occupational and environmental point of view. Benzene in blood The employees and 93 men and women with no occupational contact to benzene were examined for their blood benzene level Because smoking of tobacco is a prominent source of internal benzene exposure, both groups were subdivided according to their smoking habits The results of our examinations are presented in Table 1 No
267 Table 1 Concentrations of benzene in venous blood samples of MWI workers and of occupationally unexposed controls All concentrations are presented in Lg/l
N
+SD
17
0 459 ± 0 222 (0.370 ;
0.170
0 860 36
(0.195 ; 0 395)
