Elsevier

Chemosphere

Volume 47, Issue 1, April 2002, Pages 57-64
Chemosphere

Chromosomal damage in peripheral blood lymphocytes of traffic policemen and taxi drivers exposed to urban air pollution

https://doi.org/10.1016/S0045-6535(01)00185-0Get rights and content

Abstract

Urban air contains a diversity of chemical compounds, some of which are genotoxins. An increased risk of cancer has also been reported in occupations with heavy exposure to traffic-related pollution. The aim of this study was to assess the cytogenetic effects of urban air pollution by analyzing the chromosomal aberration (CA) frequencies in lymphocytes and to estimate the polycyclic aromatic hydrocarbons (PAHs) exposure by measuring urinary 1-hydroxypyrene (1-OHP) levels. A total of 15 traffic policemen and 17 taxi drivers working in the city of Ankara were the exposed groups and 23 healthy men working in the office departments were the control group. The overall mean±S.D. values of 1-OHP excretions of traffic policemen, taxi drivers and control subjects were 0.59±0.40μmol/mol creatinine, 0.32±0.25μmol/mol creatinine and 0.57±0.36μmol/mol creatinine, respectively. Urinary 1-OHP levels of nonsmoking policemen were significantly greater than those of nonsmoking control subjects (p<0.05). The overall mean±S.D. values for CA frequencies (%) from policemen, taxi drivers and control group were 1.29±1.59, 1.81±1.79, and 0.26±0.73, respectively. There was a significantly greater frequency of CAs in exposed groups relative to the matched control population (p<0.05;p<0.01). Age, sex and smoking habits have not influenced the cytogenetic end-point in this study. Our results demonstrate that occupational exposure to urban air pollutants leads to a significant induction of cytogenetic damage in peripheral lymphocytes of traffic policemen and taxi drivers.

Introduction

Air pollution has been generally recognized as a health hazard. A number of epidemiological studies have shown that people living in urban areas have an increased risk of lung cancer compared to people living outside metropolitan areas (Hemminki and Pershagen, 1994). An increased risk of cancer has also been reported in occupations with heavy exposure to traffic-related air pollution (Hayes et al., 1989; Guberan et al., 1992).

Urban air contains a diversity of chemical compounds, some of which are genotoxins. The most important source of genotoxins in air pollution is incomplete combustion of fossil fuels, e.g., automobile exhaust, residential heating and industrial emissions (Lewtas, 1993; Nielsen et al., 1996a, Nielsen et al., 1996b). The composition of automobile exhaust is complex and generally contains carbon monoxide, nitrogen oxides, particulates and hydrocarbons – especially the polycyclic aromatic hydrocarbons (PAHs), nitroaromatics, benzene, 1,3-butadiene, sulfur dioxide and lead (IARC, 1989). Heavy diesel engines, buses, and trucks contribute approximately 50–60% of the traffic emissions in urban areas, and exhaust from diesel-powered engines has been classified as a Group 2A carcinogen according to the International Agency for Research on Cancer (IARC), whereas gasoline-engine exhaust has been classified as a Group 2B carcinogen (IARC, 1989; IPCS, 1996).

Local residents and special occupational populations, such as bus drivers, street policemen and street vendors, have been studied as model populations to assess the contribution of urban air pollution to DNA damage of urban residents (Anwar and Kamal, 1988; Bostrom et al., 1994; Hemminki et al., 1994; Nielsen et al., 1996a, Nielsen et al., 1996b; Pastorelli et al., 1996; Peluso et al., 1998; Autrup et al., 1999; Knudsen et al., 1999).

Different biomarkers have been used to assess exposure to genotoxic compounds in general and occupational environment, ranging from the presence of mutagenic activity in urine to the induction of chromosomal damage in target and surrogate tissues (Sram and Binkova, 2000). PAHs are a major group of carcinogenic compounds in ambient urban air, and most recent biomarker studies have focused on assessing PAH exposure. Urinary 1-OHP, a metabolite of pyrene estimating the total uptake of PAHs, has been proposed as a biological marker of individual internal dose (Merlo et al., 1998). Increased urinary levels of 1-OHP have been reported in human biomonitoring studies including subjects occupationally exposed to bitumen fumes, coal tar ointments, workers in engine repair workshops and so on (Jongeneelen et al., 1985; Burgaz et al., 1992, Burgaz et al., 1998; Karahalil et al., 1998; Merlo et al., 1998).

Biomonitoring studies of human populations environmentally and/or occupationally exposed to high levels of complex mixtures of urban air pollutants reveal a genotoxic risk in humans in terms of DNA adducts (Hemminki et al., 1994) and increased incidence of chromosomal damage (Bolognesi et al., 1997a, Bolognesi et al., 1997b).

With the increasing number of vehicles in the capital city of Turkey, Ankara, the urban air pollution is also increasing. There have been about 800 000 motor vehicles in the city of Ankara (Atimtay et al., 2000). As the population group under risk due to their jobs, traffic policemen and taxi drivers are presumably exposed to air pollution at busy locations of Ankara city. The aim of this study was to assess CA levels in peripheral blood lymphocytes of traffic policemen and taxi drivers exposed to urban air pollution and to investigate whether there is an association with the exposure to PAHs typically found in urban air.

Section snippets

Subjects

The study group consisted of 15 male traffic policemen and 17 male taxi drivers potentially exposed to automobile exhaust on the heavy traffic roads in the city of Ankara. The working schedule of traffic policemen was 8 h per day 6 days per week. Taxi drivers were driving all day long 6 days a week. The 23 office workers having no occupational exposure to automobile exhaust or other chemicals were the control group.

A questionnaire requesting information about the lifestyle and health status of

Results

As can be seen in Table 1, no statistically significant differences were detected concerning age between the exposed groups and the control group. The proportion of current smokers in both exposed groups and in control subjects was similar. Among current smokers, the number of cigarettes smoked per day was also relatively homogenous in exposed and control subjects. Both exposed and control groups included moderate smokers. The number of heavy smokers (more than 20 cigarettes a day) in taxi

Discussion

Ankara is the capital city of Turkey with a population of approximately 4 million. There have been about 800 000 motor vehicles in the city of Ankara (Atimtay et al., 2000). It is known that about 8000 of these vehicles are taxis. In this study, traffic policemen and taxi drivers occupationally exposed to urban air pollution were monitored for CA frequencies.

Evaluation of human exposure to PAHs by carrying out only environmental monitoring may be inadequate due to the strong adsorption of some

Acknowledgements

The authors wish to thank all the workers who volunteered to participate. This research was financially supported by the Research Fund of the Gazi University (Grant 02/99-10).

Sema Burgaz (PhD) received her PhD degree from Ankara University, Department of Toxicology, Turkey (1983). She is the recipient of the İbrahim Etem Ulagay Drug Company prize in toxicology (1989). She has given undergraduate and graduate training courses. She has educational experience from tutoring master's and doctoral dissertations and is also conducting research. She has authored and co-authored 35 peer-reviewed in international journals and 14 publications in local journals and has four

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    Sema Burgaz (PhD) received her PhD degree from Ankara University, Department of Toxicology, Turkey (1983). She is the recipient of the İbrahim Etem Ulagay Drug Company prize in toxicology (1989). She has given undergraduate and graduate training courses. She has educational experience from tutoring master's and doctoral dissertations and is also conducting research. She has authored and co-authored 35 peer-reviewed in international journals and 14 publications in local journals and has four book chapters. She is the scientific committee member of national and international toxicology congresses organized in Turkey. She is general secretary of the Turkish Society of Toxicology.

    Gonca Çakmak Demircigil (MSc) received her MSc from Gazi University, Dept. of Toxicology, Turkey (2000). She has co-authored two peer-reviewed articles in international journals and several poster presentations in international meetings. She participated in European Societies of Toxicology Education Course on Principles of Risk Assessment in 1999 in Varna, Bulgaria. She has been at the Medical Institute for Environmental Hygiene, Toxicology of Fibers and Particles, Duesseldorf, Germany for two months for research.

    Bensu Karahalil (PhD) received her PhD degree from Gazi University in Toxicology, Turkey (1996). Following post-doctoral studies at the National Institute of Standards and Technology USA, she joined the Gazi University, Department of Toxicology. She has authored and co-authored 12 peer-reviewed articles in international journals and three publications in local journals. She has been at the NIH Aging Institute, Baltimore, USA for 3 months for post-doctoral studies.

    Ali Esat Karakaya currently holds the Chair of the Department of Toxicology at the Gazi University, Turkey. He is a fellow of the Academy of Toxicological Sciences. Dr. Karakaya is the President of the Turkish Society of Toxicology and he has organized several international meetings. Dr. Karakaya has authored and co-authored 64 peer-reviewed articles in international journals and 34 publications in local journals. He published two international books as co-editor and he has five book-chapters. He has taught Toxicology at both the graduate and the under graduate levels. He has successfully supervised three PhD and 12 MSc students.

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