[Exposure of children to benzene and other motor vehicle emissions]. / Belastung von Kindern durch Benzol und andere verkehrsbedingte Immissionen.

The concentrations of benzene, toluene, and lead and the percentage of carboxyhemoglobin (COHb) were measured in the venous blood of 48 children living in a central urban area with high traffic density (Cologne, FRG). The same parameters were also evaluated in a reference group of children (n = 72) living in a small city located in a rural area of West-Germany (Borken, Münsterland). The above named parameters could be quantitated in all blood samples. The children living in the central urban area had, on average, significantly higher concentrations of benzene, toluene, lead, and COHb in blood than the children of the reference group. The blood benzene concentrations were, on average, 71% and the toluene concentrations 56% higher in the urban children when compared to the reference group. The median values of the urban group/reference group were: benzene, 115/70 ng/l; toluene, 545/370 ng/l; lead, 5.2/4.7 micrograms/dl; COHb, 0.9/0.6%. It is concluded that the higher levels of benzene, toluene, lead, and COHb found in the blood of the urban children result from the higher atmospheric concentrations of these pollutants generally found in central urban areas with high traffic density.

[Lung function and carboxyhemoglobin during the smog episode of January 1987]. / Lungenfunktion und Carboxyhämoglobin in der Smogsituation des Januar 1987.

During a phase of elevated ambient air pollution in January 1987 the alert level of the smog alarm recommendation in Northrhine Westfalia (FRG) was reached. The average concentrations during examinations were 0.255 mg/m3 SO2 and 3.2 mg/m3 CO at the closest station. In 111 healthy persons in Cologne and Düsseldorf, resistance measured by oscillatory method was elevated during this period compared to control examinations. In 59 patients with moderate airway-obstruction from different parts of West Germany lung function showed further deterioration during the smog phase: Airway resistance measured by body-plethysmography was higher than during a control period, FVC, FEV1, PEF and MEF75 were decreased. Finally levels of carboxyhemoglobin in blood also were increased in 46 healthy nonsmokers. The investigation shows, that even in moderate smog episodes (compared to earlier years) small, but consistent changes of lung function parameter can be measured.

[Carboxyhemoglobin levels of selected population segments in variously structured and polluted areas of North Rhine-Westphalia]. / Untersuchungen zum Carboxyhämoglobingehalt ausgewählter Bevölkerungsgruppen in unterschiedlich strukturierten und belasteten Gebieten Nordrhein-Westfalens.

Measurements of carboxyhemoglobin (COHb)-content from about 13,000 inhabitants of various sites in western North Rhine-Westphalia are presented. Analyses were part of surveys on the effects of air pollution conducted between 1975 and 1980 in five designated, polluted areas. Determinations were executed in the Medical Institute for Environmental Hygiene, Duesseldorf, on behalf of the Ministry of Labour, Health and Social Administration. Analysis of blood samples for CO-content was performed by gas chromatography. Carboxyhemoglobin levels were calculated by reference to the individual hemoglobin levels. Our surveys have been conducted during several years and included different seasons. Before 1977, fifty years old men were investigated. Until 1978, sixty years old men were studied. In 1979 and 1980, sixty years old women and ten years old children were additionally incorporated into the survey. Statistical analysis of data included variables which influence personal CO-burden such as smoking, and in the case of non-smokers indoor air exposure through passive smoking, use of gas facilities and heating in the flat, as well as occupational exposure. Besides, the influence of age, sex and location was considered. The average COHb-level of the populations under study was expressed as the median of the distribution. The distribution-free Mann-Whitney U-test served for assessment of differences between groups. As a further parameter, the percentage of the measurements greater than 2,5% COHb was chosen, because it was thought to be more relevant to risk populations, i.e. people suffering from Angina pectoris. As expected, tobacco smoking exerted the greatest influence on COHb-level. In non-smokers a trend, indicating a relationship between indoor air pollution and COHb-content could be observed. If high CO gas such as coke gas was used in flats with gas facilities COHb-levels were significantly raised. Surveys performed in 1979 and in 1980 showed a sex-dependent difference between median COHb saturations, women having lower values than men. The difference of these figures between adults and children is statistically significant. Comparisons between adult nonsmokers from various sites prompted a significant difference only in the case of the Oberbergischer Kreis (County), having the lowest median COHb-value. The highest COHb-levels by far were encountered in the city of Duisburg in January 1979, when very unfavourable meterological conditions (Smog alarm, degree 1) were present. The median COHb saturations reached on this occasion were very near to the limits considered to be critical for populations at special risk.

[Increased blood-CO-content in humans and animals by incorporated halogenated hydrocarbons (author's transl)]. / Erhöhter Blut-CO-Gehalt bei Mensch und Tier durch inkorporierte halogenierte Kohlenwasserstoffe

Contrarily to the general opinion about the harmlessness of dichloromethane, clear functional disturbances of the central nervous system could be recorded by means of effect investigations as well in humans as in animals. The depressive effect on the REM-sleep of albino rats was especially well recognisable, similarly as with carbon monoxide exposure. Surprisingly the analytical investigations of the blood of these animals showed a clearly elevated blood-CO-content after exposure to dichloromethane. Further experiments during which albino rats were exposed three hours along to a dichloromethane-concentration equal to the TLV (1750 mg/m3!!) resulted in a blood-COHb-level of about 13%, corresponding to over 30 mug CO/ml blood. So high blood-COHb-levels are obtained after a three-hour-exposure to 120 ppm CO. Following these findings, a number of halogenated and oxygenated hydrocarbon compounds of the methane and ethane series were investigated relatively to their CO-forming capacity. Only the di- and trihalogenated methane derivatives were found leading to an increased blood-COHb-level. After a three hours-exposure to 1000 ppm respectively the jodoalkanes yielding about 23% COHb were strongestly, the bromoalkanes with about 20% COHb more strongly and the chloroalkanes with about 12% COHb strongly implicated in the endogenous CO-formation. By means of detailed experiments with human volunteers (non-smokers) it resulted that after eight-hours-exposure to 500 ppm dichloromethane (TLV) a mean value for CO-content in blood of about 30 mug/ml corresponding to 12% COHb was obtained, in one case raising as high as 60 mug CO/1 ml blood or 24% COHb. After an eight-hours-exposure to 100 ppm of the halocarbon, the blood-COHb-level reached 5%. The elimination was very slow, so that 24 to 26 hours were necessary to reestablish the original blood-COHb-level. These results show that the actually TLV for dichloromethane e.g. 1750 mg/m3 has to be revised, because a fifth of this value already leads to a blood-COHb-content equal to that produced by the TLV for carbon monoxide and that also eventually arising problems due to gas mixtures have to be considered and thoroughly investigated.