Journal of Toxicology and Environmental Health
ISSN: 0098-4108 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/uteh19
Air pollution and urinary thioether excretion in children of Barcelona Jordi Mallol & María Rosa Nogues To cite this article: Jordi Mallol & María Rosa Nogues (1991) Air pollution and urinary thioether excretion in children of Barcelona, Journal of Toxicology and Environmental Health, 33:2, 189-195, DOI: 10.1080/15287399109531517 To link to this article: http://dx.doi.org/10.1080/15287399109531517
Published online: 19 Oct 2009.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=uteh20 Download by: [University of Florida]
Date: 10 November 2015, At: 15:44
AIR POLLUTION AND URINARY THIOETHER EXCRETION IN CHILDREN OF BARCELONA Jordi Mallol, María Rosa Nogues
Downloaded by [University of Florida] at 15:44 10 November 2015
School of Medicine, University of Barcelona, Sant Llorenç, Spain
The polluted environment found in highly industrialized areas and in big cities contains a great quantity of electrophilic (EC) and proelectrophilic (PEC) compounds, which largely contribute to the development of several pathological processes in humans. EC and PEC can be coupled to the cysteine moiety of glutathione spontaneously or by the glutathione S-transferase system (GST), giving nontoxic metabolites that can be eliminated as urinary thioethers (UT). Therefore one approach to establishing the degree of impact of EC and PEC on the human body is the analysis of UT in the population living in polluted environments. The work presented here has been carried out in the city of Barcelona with a group of 50 children living in a polluted area, over a 12-mo period. Our results demonstrate that UT are significantly higher when the amounts of air pollutants (AP) increase; although the level of contamination never exceeded the established "safe limits," UT reached values similar to those found in people smoking more than 10 cigarettes/d. These results may contribute to establishing the maximal levels of contamination compatible with a healthy life, on the basis of patterns of true salubrity rather than on political and economic criteria.
INTRODUCTION The chemical nature of AP is very complex, especially in big cities with a significant industrial environment. Together with well-defined pollutants such as SO2, NOX, CO, etc., several polycyclic aromatic hydrocarbons (PAH) are also found. These PAH are produced in chemical industries, combustion of petroleum derivatives (vehicles, heating, power stations), incinerators, etc. and possess electrophilic and proelectrophilic properties (Jongeneelen et al., 1986). PEC can easily be oxidized and converted to EC through oxidative systems (i.e., aryl hydrocarbon hydroxylase), and intermediate epoxides may react with DNA and other macromolecules forming covalent bonds and leading to irreversible lesions (Van Doom et al., 1981). Fortunately, most of these EC and PEC comWe are grateful to Drs. G. Massagué and J. I. Olivella (Servei de Control Ambiental de la Entitat del Medi Ambient de l'Area Metropolitana de Barcelona), who furnished the air pollution data; to the Reis Catolics School which permitted the development of the work; and to Mr. R. Rycroft (University of Barcelona) for supervising this manuscript. This work was carried out with a grant of the Spanish Fondo de Investigaciones Sanitarias de la Seguridad Social and with the technical assistance of Mrs. N. Argany. Requests for reprints should be sent to Jordi Mallol, School of Medicine, University of Barcelona, c/ Sant Llorenç, 21, 43201—REUS (Tarragona), Spain. 189 Journal of Toxicology and Environmental Health, 33:189-195, 1991 Copyright © 1991 by Hemisphere Publishing Corporation
Downloaded by [University of Florida] at 15:44 10 November 2015
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J. MALLOL AND M. R. NOGUES
pounds can be neutralized by several systems, among which conjugation with glutathione (GSH) is of utmost importance. This conjugation can take place either spontaneously or through the transferase activity of the GST system, and the EC compounds appear in the urine as inactive metabolites (UT) (Habig et al., 1974). The impact of EC and PEC can also be confirmed by urinary mutagenic methods like the Ames test. The analysis of UT and the Ames test have thus been used to monitor human exposure to several EC and PEC substances (Mallol et al., 1987), but, to our knowledge, this kind of approach has not been applied to the determination of the continuous impact of urban pollution on the human population. In a previous paper (Lafuente et al., 1987) we demonstrated that children living in polluted areas of Barcelona had more UT than those living in nonpolluted areas. That study was performed simultaneously in six schools but with only one sample of urine per subject. Hence the differences observed could have been due not only to the different amounts of AP but also to nutritional or social factors. In order to eliminate such factors and to confirm our previous hypothesis, we performed the study reported here. SUBJECTS AND METHODS Thirty-four pupils (17 boys and 17 girls, 9-10 yr old) at a state school participated in our study. All of them were residents in a polluted area of Barcelona in the vicinity of the school. Their participation was obtained with parental consent and also with that of the director of the school. They were healthy and none smoked, nor was a passive smoker, nor took drugs that could interfere with our study. Two automated pollution monitoring stations are located at 600 and 900 m from the school; thus we have monitored throughout the study the main parameters of air pollution, that is, SO2 and nonsedimentable particles (NSP). SO2 was collected by an impinger and determined by colorimetry using the reagent thorin. NSP were collected in a small captair fitted with a Whatman filter and determined by refractometry. This work was developed in the course of 1 yr, from February to January. We obtained urine samples in the following months: February, March, April, May, November, and January, once each month. The urine samples were collected around 11:00 a.m. at the end of the school week (Thursday or Friday). Urine samples were kept at — 20°C immediately after collection until use (maximum 20 d). UT were determined by the method of Van Doom et al. (1980), using a nitrogen stream and hot plate to evaporate the ethyl acetate extract followed by alkaline hydrolysis, and the SH content was calculated by the method described by Ellman (1959). The urinary creatinine was assayed by the method of Jaffa with a commercial kit (Sigma
AIR POLLUTION AND URINARY THIOETHERS
191
Chemical Co.). Urines with creatinine values under 5 mmol/l were discarded. Each experimental point was done in duplicate. Mean values for SO2 and NSP were calculated taking together the value corresponding to the day of urine collection and the values of the 3 preceding days, for both detecting stations.
Downloaded by [University of Florida] at 15:44 10 November 2015
RESULTS AND DISCUSSION
During the period studied the pollution values were not very high, or rather low, in comparison with other values that are frequently recorded in Barcelona. Only in the first and the last samplings were there relative peaks of air pollution. For the rest of the period the pollutants were roughly the same and clearly below what is considered peaks of contamination. The highest values were found at the end of the study (January), as is usual in periods with atmospheric thermal inversion and the use of domestic and industrial heating, whereas the lowest results were found in March (Table 1). It was not possible to obtain urine samples from all the children at each determination. Sometimes this was due to the impossibility of micturition at the sampling time, in other cases because the creatinine levels were too low, and finally because of absenteeism of the pupils during urine collection. In this sense, the minimal compliance was obtained in February (17 subjects) and the maximal in January (29 subjects). Only seven children participated in all the determinations. The values of UT obtained in each determination as well as the number of subjects are shown in Table 1. In January (at the end of the study) the mean value of UT was 8 ¿imol SH/mmol creatinine, with a maximal value of 20.4 in one of the children. These values are significantly higher than those obtained in March (maximal value 11.8) or November (maximal value 6.3), with a mean value for both months of 3.7 /¿mol SH/mmol creatinine. Correlations of UT with SO2 and UT with NSP were significantly positive for the group of seven TABLE 1. Mean Values ± SD for Air Pollutants and Urinary Thioethers (UT) in the Whole Sample Month
SO2
February March April May November January
59.5 21.2 28.1 36.4 38.7 92.3
UT
NSP ± ± ± ± ± ±
30.7 13.2 15.6 25.8 27.2 36.3
89 49.4 82.2 72.4 77.6 139
± + ± + + +
72.7 33.1 55.1 55.9 68.9 85.4
7.2 3.7 4.5 4.4 3.7 8
n ± ± ± ± ± ±
2.2 2.4 1.6 2.5 1.9 3.6
17 23 24 26 27 29
Note. SO2 and nonsedimentable particles (NSP) are reported in uglm3. UT are reported in /¿mol SH/mmol creatinine; n = number of cases.
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J. MALLOL AND M. R. NOGUES
children who participated in all determinations as well as for the whole population (Fig. 1). The peaks of AP and UT that were found in February and January are statistically significant (Mann-Whitney CZ-test) with the following p values: (1) for SO2,1.6 x 10~3 in February and 2.2 x 1(T3 in January, (2) for NSP, 0.03 in January, and (3) for UT, 4.8 X 10~5 in February and 3.6 x 10~7 in January. Many reports have been published about the advantages and disadvantages of using UT as biological markers of exposure and impact on humans (Lauwerys and Bernard, 1985; Vermeulen, 1989). The analysis of UT gives nonspecific information about the chemical nature of the EC, but in contrast it is a useful method to measure exposure to heterogeneous and unknown compounds, especially in large groups of individuals. It is widely accepted that in controlled groups the increase of UT correlates well with the presence of pollutants in the environment. On the other hand, it is also clearly demonstrated that the increase of AP, especially in industrial areas and in big cities, has detrimental effects on the health. One of these aspects that has been extensively studied is the relationship between AP and pulmonary diseases, because the main target organs are the lungs (Cohen et al., 1972; Perry et al., 1983; Schrenk et al., 1949; Villalbí et al., 1984). From our results, we can conclude that the increase in UT observed during the periods of maximal contamination must be due to the presence in the air of EC or PEC that are neutralized by GSH, either spontaneously or by the GST system. We do not know the precise chemical nature of these AP responsible for the increase of UT, but PAH are probably involved together with the other pollutants detected. It is well known that in big cities PAH are found in the NSP, and it has been demonstrated that the presence of PAH correlates with the values found for SO2, NSP, and other AP that are currently detected (Aceves et al., 1989). We previously reported the UT values that can be found in smokers and nonsmokers living in a nonpolluted environment (Lafuente and Mallol, 1986). The amount of UT detected in the present study during the periods of maximum contamination is similar to that observed in smokers of 10-20 cigarettes/d. In addition, the increase of UT found during the contamination peaks is higher than that described by other authors in subjects exposed to anesthetics (Pasquini et al., 1989) or to chemical incinerators (Van Doom et al., 1981). Regulations concerning the "safe limits" of AP are complex, depending on whether we consider the median values for 1 yr or the maximum values accepted in a 24-h period for 3 consecutive days; these limits can also be higher in winter. As an example, in the European Economic Community (EEC) the maximum values accepted in winter are 130 fig/m3 for SO2 and NSP as a mean, but values of 250 ^g/m3 are accepted for a 3-d period. In the United States the maximum values permitted are 365 ¡xg/vn3
AIR POLLUTION AND URINARY THIOETHERS
193
Limol SH/mmol creatinine 12r 10 8 6
Downloaded by [University of Florida] at 15:44 10 November 2015
4 2
20
40
60 80 100 SO2 (ug/m3)
120
140
120
140
(a)
Limol SH/mmol creatinine
20
40
60 80 100 NSP (gg/m3) (b)
FIGURE 1. Correlations between UT and air pollutants, for the whole sample (•) and for the seven cases that participated in all determinations (•). (a) Correlation of UT with SO2 is positive for r - .53, p < .01 in (•) and for r - .61, p < .01 in (•). (fa) Correlation of UT with NSP is positive for r - .5, p < .01 in (•) and for r - .56, p < .01 in (•).
Downloaded by [University of Florida] at 15:44 10 November 2015
194
I. MALLOL AND M. R. NOGUES
for SO2 and 150 /¿g/m3 for NSP (see EEC regulation 89/427/EEC). If the air pollution had been higher (near or above the "safe limits" established, as sometimes happens in Barcelona and other big cities) we can suppose that the levels of UT could have been much higher than those found here, probably equivalent to those existing in heavy smokers (more than 20 cigarettes/d). In any case, we can confirm that with values of air pollution above 60 ¿tg/m3 for SO2 or 80 ¿tg/m3 for NSP, the amounts of UT are higher than those found in nonsmokers and, in general, in nonexposed subjects. If the continuous impact of these pollutants leads to a nonhealthy condition, as seems well established, then health authorities must reconsider what the limits of air pollutants that are compatible with good health should be. Biological studies on the exposed subject, such as the ones we have carried out, epidemiological studies on morbidity in polluted areas, and other studies able to demonstrate the impact degree of AP on humans must replace, as soon as possible, the present arbitrary means of determining the permissible limits of these pollutants.
REFERENCES Aceves, M., Farres, E., Bustems, L., Massague, G., Montells, R., and Serena, J. M. 1989. Survey and relationships of organic and inorganic air pollutants in the Barcelona metropolitan area. 8th World Clean Air Congress, The Hague. Cohen, A. A., Bromberg, S., Buechley, R. W., Heiderscheit, L. T., and Shy, C. M. 1972. Asthma and air pollution from a coal-fueled power plant. Am. J. Public Health 62:1181-1188. Ellman, G. L. 1959. Tissue sulphydryl groups. Arch. Biochem. Biophys. 82:70-77. Habig, W. H., Pabst, M. J., and Jakoby, W. H. 1974. Glutathione S-transferases. The first enzymatic step in mercapturic acid formation. J. Biol. Chem. 249:7130-7139. Jongeneelen, F. J., Bos, R. P., Anzion, R. B. M., Thews, J. L. G., and Henderson, P. T. 1986. Biological monitoring of polycyclic aromatic hydrocarbons metabolites in urine. Scand. J. Work. Environ. Health 12:137-143. Lafuente, A., and Mallol, J. 1986. Urinary thioethers in low tar cigarette smokers. Public Health 100:392-398. Lafuente, A., Cobos, A., and Mallol, J. 1987. A pilot study of urinary thioethers as biological indicators of the urban contamination. Public Health 101:267-276. Lauwerys, R., and Bernard, A. 1985. Les marqueurs biologiques d'exposition aux agents toxiques. Rev. Epidémiol. Santé Publique 33:255-261. Mallol, J., Lafuente, A., Festy, B., Sancho-Garnier, H., Henderson, P. T., and Bos, R. P. 1987. Tioéteres y mutágenos en orina: Posibles predictores de riesgo en el cáncer de pulmón. Med. Clin. 89(suppl. 1):10-15. Pasquini, R., Monarca, S., Scassellati, G., Bauleo, F. A., Angeli, G., and Cerami, F. 1989. Thioethers, mutagens and D-glucaric acid in urine of operating room personnel exposed to anesthetics. Teratogen. Carcinogen. Mutagen. 9:359-368. Perry, G. B., Chai, H., Dickey, D. W., Jones, R. H., Kinsman, R. A., Morill, C. G., Spector, S. L., and Weiser, P. C. 1983. Effects of particulate air pollution on asthmatics. Am. J. Public Health 73:5056. Schrenk, H. N., Heimann, H., Clayton, G. D., Gafafer, W. M., and Wexler, H. 1949. Air pollution in Donora, Pennsylvania. Epidemiology of the unusual smog episode of October 1948. Public Health 306:1-171. Van Doorn, R., Borm, P. J. A., Leijdekkers, C. M., Henderson, P. T., Reuvers, J., and Van Bergen, T. J.
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1980. Detection and identification of S-methylcysteine in urine of workers exposed to methyl chloride. Int. Arch. Occup. Environ. Health 46:99-109. Van Doorn, R., Leijdekkers, C. M., Bos, R. P., Brouns, R. M. E., and Henderson, P. T. 1981. Detection of human exposure to electrophilic compounds by assay of thioether detoxication products in urine. Ann. Occup. Hyg. 24:77-92. Vermeulen, N. P. E. 1989. Analysis of mercapturic acid as a tool in biotransformation, biomonitoring and toxicological studies. Trends Pharmacol. Sci. 10:177-181. Villalbl, J. R., Marti, J., Auli, E., Conillera, P., and Milla, J. 1984. Morbididad respiratoria y contaminación atmosférica. Med. Clin. 82:695-697.
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Received June 6, 1990 Accepted January 9, 1991
ISSN: 0098-4108 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/uteh19
Air pollution and urinary thioether excretion in children of Barcelona Jordi Mallol & María Rosa Nogues To cite this article: Jordi Mallol & María Rosa Nogues (1991) Air pollution and urinary thioether excretion in children of Barcelona, Journal of Toxicology and Environmental Health, 33:2, 189-195, DOI: 10.1080/15287399109531517 To link to this article: http://dx.doi.org/10.1080/15287399109531517
Published online: 19 Oct 2009.
Submit your article to this journal
Article views: 1
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=uteh20 Download by: [University of Florida]
Date: 10 November 2015, At: 15:44
AIR POLLUTION AND URINARY THIOETHER EXCRETION IN CHILDREN OF BARCELONA Jordi Mallol, María Rosa Nogues
Downloaded by [University of Florida] at 15:44 10 November 2015
School of Medicine, University of Barcelona, Sant Llorenç, Spain
The polluted environment found in highly industrialized areas and in big cities contains a great quantity of electrophilic (EC) and proelectrophilic (PEC) compounds, which largely contribute to the development of several pathological processes in humans. EC and PEC can be coupled to the cysteine moiety of glutathione spontaneously or by the glutathione S-transferase system (GST), giving nontoxic metabolites that can be eliminated as urinary thioethers (UT). Therefore one approach to establishing the degree of impact of EC and PEC on the human body is the analysis of UT in the population living in polluted environments. The work presented here has been carried out in the city of Barcelona with a group of 50 children living in a polluted area, over a 12-mo period. Our results demonstrate that UT are significantly higher when the amounts of air pollutants (AP) increase; although the level of contamination never exceeded the established "safe limits," UT reached values similar to those found in people smoking more than 10 cigarettes/d. These results may contribute to establishing the maximal levels of contamination compatible with a healthy life, on the basis of patterns of true salubrity rather than on political and economic criteria.
INTRODUCTION The chemical nature of AP is very complex, especially in big cities with a significant industrial environment. Together with well-defined pollutants such as SO2, NOX, CO, etc., several polycyclic aromatic hydrocarbons (PAH) are also found. These PAH are produced in chemical industries, combustion of petroleum derivatives (vehicles, heating, power stations), incinerators, etc. and possess electrophilic and proelectrophilic properties (Jongeneelen et al., 1986). PEC can easily be oxidized and converted to EC through oxidative systems (i.e., aryl hydrocarbon hydroxylase), and intermediate epoxides may react with DNA and other macromolecules forming covalent bonds and leading to irreversible lesions (Van Doom et al., 1981). Fortunately, most of these EC and PEC comWe are grateful to Drs. G. Massagué and J. I. Olivella (Servei de Control Ambiental de la Entitat del Medi Ambient de l'Area Metropolitana de Barcelona), who furnished the air pollution data; to the Reis Catolics School which permitted the development of the work; and to Mr. R. Rycroft (University of Barcelona) for supervising this manuscript. This work was carried out with a grant of the Spanish Fondo de Investigaciones Sanitarias de la Seguridad Social and with the technical assistance of Mrs. N. Argany. Requests for reprints should be sent to Jordi Mallol, School of Medicine, University of Barcelona, c/ Sant Llorenç, 21, 43201—REUS (Tarragona), Spain. 189 Journal of Toxicology and Environmental Health, 33:189-195, 1991 Copyright © 1991 by Hemisphere Publishing Corporation
Downloaded by [University of Florida] at 15:44 10 November 2015
190
J. MALLOL AND M. R. NOGUES
pounds can be neutralized by several systems, among which conjugation with glutathione (GSH) is of utmost importance. This conjugation can take place either spontaneously or through the transferase activity of the GST system, and the EC compounds appear in the urine as inactive metabolites (UT) (Habig et al., 1974). The impact of EC and PEC can also be confirmed by urinary mutagenic methods like the Ames test. The analysis of UT and the Ames test have thus been used to monitor human exposure to several EC and PEC substances (Mallol et al., 1987), but, to our knowledge, this kind of approach has not been applied to the determination of the continuous impact of urban pollution on the human population. In a previous paper (Lafuente et al., 1987) we demonstrated that children living in polluted areas of Barcelona had more UT than those living in nonpolluted areas. That study was performed simultaneously in six schools but with only one sample of urine per subject. Hence the differences observed could have been due not only to the different amounts of AP but also to nutritional or social factors. In order to eliminate such factors and to confirm our previous hypothesis, we performed the study reported here. SUBJECTS AND METHODS Thirty-four pupils (17 boys and 17 girls, 9-10 yr old) at a state school participated in our study. All of them were residents in a polluted area of Barcelona in the vicinity of the school. Their participation was obtained with parental consent and also with that of the director of the school. They were healthy and none smoked, nor was a passive smoker, nor took drugs that could interfere with our study. Two automated pollution monitoring stations are located at 600 and 900 m from the school; thus we have monitored throughout the study the main parameters of air pollution, that is, SO2 and nonsedimentable particles (NSP). SO2 was collected by an impinger and determined by colorimetry using the reagent thorin. NSP were collected in a small captair fitted with a Whatman filter and determined by refractometry. This work was developed in the course of 1 yr, from February to January. We obtained urine samples in the following months: February, March, April, May, November, and January, once each month. The urine samples were collected around 11:00 a.m. at the end of the school week (Thursday or Friday). Urine samples were kept at — 20°C immediately after collection until use (maximum 20 d). UT were determined by the method of Van Doom et al. (1980), using a nitrogen stream and hot plate to evaporate the ethyl acetate extract followed by alkaline hydrolysis, and the SH content was calculated by the method described by Ellman (1959). The urinary creatinine was assayed by the method of Jaffa with a commercial kit (Sigma
AIR POLLUTION AND URINARY THIOETHERS
191
Chemical Co.). Urines with creatinine values under 5 mmol/l were discarded. Each experimental point was done in duplicate. Mean values for SO2 and NSP were calculated taking together the value corresponding to the day of urine collection and the values of the 3 preceding days, for both detecting stations.
Downloaded by [University of Florida] at 15:44 10 November 2015
RESULTS AND DISCUSSION
During the period studied the pollution values were not very high, or rather low, in comparison with other values that are frequently recorded in Barcelona. Only in the first and the last samplings were there relative peaks of air pollution. For the rest of the period the pollutants were roughly the same and clearly below what is considered peaks of contamination. The highest values were found at the end of the study (January), as is usual in periods with atmospheric thermal inversion and the use of domestic and industrial heating, whereas the lowest results were found in March (Table 1). It was not possible to obtain urine samples from all the children at each determination. Sometimes this was due to the impossibility of micturition at the sampling time, in other cases because the creatinine levels were too low, and finally because of absenteeism of the pupils during urine collection. In this sense, the minimal compliance was obtained in February (17 subjects) and the maximal in January (29 subjects). Only seven children participated in all the determinations. The values of UT obtained in each determination as well as the number of subjects are shown in Table 1. In January (at the end of the study) the mean value of UT was 8 ¿imol SH/mmol creatinine, with a maximal value of 20.4 in one of the children. These values are significantly higher than those obtained in March (maximal value 11.8) or November (maximal value 6.3), with a mean value for both months of 3.7 /¿mol SH/mmol creatinine. Correlations of UT with SO2 and UT with NSP were significantly positive for the group of seven TABLE 1. Mean Values ± SD for Air Pollutants and Urinary Thioethers (UT) in the Whole Sample Month
SO2
February March April May November January
59.5 21.2 28.1 36.4 38.7 92.3
UT
NSP ± ± ± ± ± ±
30.7 13.2 15.6 25.8 27.2 36.3
89 49.4 82.2 72.4 77.6 139
± + ± + + +
72.7 33.1 55.1 55.9 68.9 85.4
7.2 3.7 4.5 4.4 3.7 8
n ± ± ± ± ± ±
2.2 2.4 1.6 2.5 1.9 3.6
17 23 24 26 27 29
Note. SO2 and nonsedimentable particles (NSP) are reported in uglm3. UT are reported in /¿mol SH/mmol creatinine; n = number of cases.
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J. MALLOL AND M. R. NOGUES
children who participated in all determinations as well as for the whole population (Fig. 1). The peaks of AP and UT that were found in February and January are statistically significant (Mann-Whitney CZ-test) with the following p values: (1) for SO2,1.6 x 10~3 in February and 2.2 x 1(T3 in January, (2) for NSP, 0.03 in January, and (3) for UT, 4.8 X 10~5 in February and 3.6 x 10~7 in January. Many reports have been published about the advantages and disadvantages of using UT as biological markers of exposure and impact on humans (Lauwerys and Bernard, 1985; Vermeulen, 1989). The analysis of UT gives nonspecific information about the chemical nature of the EC, but in contrast it is a useful method to measure exposure to heterogeneous and unknown compounds, especially in large groups of individuals. It is widely accepted that in controlled groups the increase of UT correlates well with the presence of pollutants in the environment. On the other hand, it is also clearly demonstrated that the increase of AP, especially in industrial areas and in big cities, has detrimental effects on the health. One of these aspects that has been extensively studied is the relationship between AP and pulmonary diseases, because the main target organs are the lungs (Cohen et al., 1972; Perry et al., 1983; Schrenk et al., 1949; Villalbí et al., 1984). From our results, we can conclude that the increase in UT observed during the periods of maximal contamination must be due to the presence in the air of EC or PEC that are neutralized by GSH, either spontaneously or by the GST system. We do not know the precise chemical nature of these AP responsible for the increase of UT, but PAH are probably involved together with the other pollutants detected. It is well known that in big cities PAH are found in the NSP, and it has been demonstrated that the presence of PAH correlates with the values found for SO2, NSP, and other AP that are currently detected (Aceves et al., 1989). We previously reported the UT values that can be found in smokers and nonsmokers living in a nonpolluted environment (Lafuente and Mallol, 1986). The amount of UT detected in the present study during the periods of maximum contamination is similar to that observed in smokers of 10-20 cigarettes/d. In addition, the increase of UT found during the contamination peaks is higher than that described by other authors in subjects exposed to anesthetics (Pasquini et al., 1989) or to chemical incinerators (Van Doom et al., 1981). Regulations concerning the "safe limits" of AP are complex, depending on whether we consider the median values for 1 yr or the maximum values accepted in a 24-h period for 3 consecutive days; these limits can also be higher in winter. As an example, in the European Economic Community (EEC) the maximum values accepted in winter are 130 fig/m3 for SO2 and NSP as a mean, but values of 250 ^g/m3 are accepted for a 3-d period. In the United States the maximum values permitted are 365 ¡xg/vn3
AIR POLLUTION AND URINARY THIOETHERS
193
Limol SH/mmol creatinine 12r 10 8 6
Downloaded by [University of Florida] at 15:44 10 November 2015
4 2
20
40
60 80 100 SO2 (ug/m3)
120
140
120
140
(a)
Limol SH/mmol creatinine
20
40
60 80 100 NSP (gg/m3) (b)
FIGURE 1. Correlations between UT and air pollutants, for the whole sample (•) and for the seven cases that participated in all determinations (•). (a) Correlation of UT with SO2 is positive for r - .53, p < .01 in (•) and for r - .61, p < .01 in (•). (fa) Correlation of UT with NSP is positive for r - .5, p < .01 in (•) and for r - .56, p < .01 in (•).
Downloaded by [University of Florida] at 15:44 10 November 2015
194
I. MALLOL AND M. R. NOGUES
for SO2 and 150 /¿g/m3 for NSP (see EEC regulation 89/427/EEC). If the air pollution had been higher (near or above the "safe limits" established, as sometimes happens in Barcelona and other big cities) we can suppose that the levels of UT could have been much higher than those found here, probably equivalent to those existing in heavy smokers (more than 20 cigarettes/d). In any case, we can confirm that with values of air pollution above 60 ¿tg/m3 for SO2 or 80 ¿tg/m3 for NSP, the amounts of UT are higher than those found in nonsmokers and, in general, in nonexposed subjects. If the continuous impact of these pollutants leads to a nonhealthy condition, as seems well established, then health authorities must reconsider what the limits of air pollutants that are compatible with good health should be. Biological studies on the exposed subject, such as the ones we have carried out, epidemiological studies on morbidity in polluted areas, and other studies able to demonstrate the impact degree of AP on humans must replace, as soon as possible, the present arbitrary means of determining the permissible limits of these pollutants.
REFERENCES Aceves, M., Farres, E., Bustems, L., Massague, G., Montells, R., and Serena, J. M. 1989. Survey and relationships of organic and inorganic air pollutants in the Barcelona metropolitan area. 8th World Clean Air Congress, The Hague. Cohen, A. A., Bromberg, S., Buechley, R. W., Heiderscheit, L. T., and Shy, C. M. 1972. Asthma and air pollution from a coal-fueled power plant. Am. J. Public Health 62:1181-1188. Ellman, G. L. 1959. Tissue sulphydryl groups. Arch. Biochem. Biophys. 82:70-77. Habig, W. H., Pabst, M. J., and Jakoby, W. H. 1974. Glutathione S-transferases. The first enzymatic step in mercapturic acid formation. J. Biol. Chem. 249:7130-7139. Jongeneelen, F. J., Bos, R. P., Anzion, R. B. M., Thews, J. L. G., and Henderson, P. T. 1986. Biological monitoring of polycyclic aromatic hydrocarbons metabolites in urine. Scand. J. Work. Environ. Health 12:137-143. Lafuente, A., and Mallol, J. 1986. Urinary thioethers in low tar cigarette smokers. Public Health 100:392-398. Lafuente, A., Cobos, A., and Mallol, J. 1987. A pilot study of urinary thioethers as biological indicators of the urban contamination. Public Health 101:267-276. Lauwerys, R., and Bernard, A. 1985. Les marqueurs biologiques d'exposition aux agents toxiques. Rev. Epidémiol. Santé Publique 33:255-261. Mallol, J., Lafuente, A., Festy, B., Sancho-Garnier, H., Henderson, P. T., and Bos, R. P. 1987. Tioéteres y mutágenos en orina: Posibles predictores de riesgo en el cáncer de pulmón. Med. Clin. 89(suppl. 1):10-15. Pasquini, R., Monarca, S., Scassellati, G., Bauleo, F. A., Angeli, G., and Cerami, F. 1989. Thioethers, mutagens and D-glucaric acid in urine of operating room personnel exposed to anesthetics. Teratogen. Carcinogen. Mutagen. 9:359-368. Perry, G. B., Chai, H., Dickey, D. W., Jones, R. H., Kinsman, R. A., Morill, C. G., Spector, S. L., and Weiser, P. C. 1983. Effects of particulate air pollution on asthmatics. Am. J. Public Health 73:5056. Schrenk, H. N., Heimann, H., Clayton, G. D., Gafafer, W. M., and Wexler, H. 1949. Air pollution in Donora, Pennsylvania. Epidemiology of the unusual smog episode of October 1948. Public Health 306:1-171. Van Doorn, R., Borm, P. J. A., Leijdekkers, C. M., Henderson, P. T., Reuvers, J., and Van Bergen, T. J.
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1980. Detection and identification of S-methylcysteine in urine of workers exposed to methyl chloride. Int. Arch. Occup. Environ. Health 46:99-109. Van Doorn, R., Leijdekkers, C. M., Bos, R. P., Brouns, R. M. E., and Henderson, P. T. 1981. Detection of human exposure to electrophilic compounds by assay of thioether detoxication products in urine. Ann. Occup. Hyg. 24:77-92. Vermeulen, N. P. E. 1989. Analysis of mercapturic acid as a tool in biotransformation, biomonitoring and toxicological studies. Trends Pharmacol. Sci. 10:177-181. Villalbl, J. R., Marti, J., Auli, E., Conillera, P., and Milla, J. 1984. Morbididad respiratoria y contaminación atmosférica. Med. Clin. 82:695-697.
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Received June 6, 1990 Accepted January 9, 1991
