Environmental and biological monitoring of benzene in traffic policemen, police drivers and rural outdoor male workers

False positives and false negatives in benzene biological monitoring

Benzene is a commonly used industrial chemical that is a significant environmental pollutant. Occupational health specialists and industrial toxicologists are concerned with determining the exact amount of exposure to chemicals in the workplace. There are two main approaches to assess chemical exposure; air monitoring and biological monitoring. Air monitoring has limitations, which biological monitoring overcomes and could be used as a supplement to it. However, there are several factors that influence biological monitoring results. It would be possible to assess exposure more accurately if these factors were taken into account. This study aimed to review published papers for recognizing and discussing parameters that could affect benzene biological monitoring. Two types of effects can be distinguished: positive and negative effects. Factors causing positive effects will increase the metabolite concentration in urine more than expected. Furthermore, the parameters that decrease the urinary metabolite level were referred to as false negatives. From the papers, sixteen influential factors were extracted that might affect benzene biological monitoring results. Identified factors were clarified in terms of their nature and mechanism of action. It is also important to note that some factors influence the quantity and quality of the influence of other factors. As a result of this study, a decision-making protocol was developed for interpreting the final results of benzene biological monitoring.

Biological exposure indices of occupational exposure to benzene: A systematic review

The current study aimed to systematically review the studies concerning the biological monitoring of benzene exposure in occupational settings. A systematic literature review was conducted in Scopus, EMBASE, Web of Science, and Medline from 1985 through July 2021. We included peer-reviewed original articles that investigated the association between occupational exposure to benzene and biological monitoring. We identified 4786 unique citations, of which 64 cross-sectional, one case-control, and one cohort study met our inclusion criteria. The most studied biomarkers were urinary trans-trans muconic acid, S- phenyl mercapturic acid, and urinary benzene, respectively. We found the airborne concentration of benzene as a key indicator for choosing a suitable biomarker. We suggest considering urinary benzene at low (0.5-5.0 TLV), urinary SPMA and TTMA at medium (5.0-25 and 25-50 TLV, respectively), and urinary phenol and hydroquinone and catechol at very high concentrations (500 and 1000 TLV ≤, respectively). Genetic polymorphism of glutathione S-transferase and oral intake of sorbic acid have confounding effects on the level of U-SPMA and U-TTMA, respectively. The airborne concentration, smoking habit, oral consumption of sorbic acid, and genetic polymorphism of workers should be considered in order to choose the appropriate indicator for biological monitoring of benzene exposure.

Cadmium and lipid balance in outdoor workers exposed to urban stressor

The aim of our study was to evaluate the association between levels of blood and urinary cadmium and lipid balance in a group of outdoor workers. The study was conducted on a group of 146 individuals (average age 45,1 ± 8,5). Blood and urinary samples were collected for the detection of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, blood cadmium and urinary cadmium. We divided the group of workers into two subgroups according to the task:75 traffic policemen and 71 police drivers. Gender differences were found. The Pearson correlation coefficient showed a positive association between blood and urinary cadmium levels and total cholesterol, LDL and triglycerides levels. Total cholesterol, LDL cholesterol and triglycerides were significantly higher in the group of traffic policemen than in police drivers. In conclusion, the results suggest a statistically significant association between blood and urinary cadmium levels and lipid balance contributing to an increase of the cardiovascular risk.

Health impact assessment of auto rickshaw and cab drivers due to exposure to vehicular pollution in Delhi: an integrated approach

Vehicular emission is an important contributor to air pollution in the urban environment and impacts the health of commuters as well as drivers. The in-vehicle concentration of pollutants is known to be higher than the ambient environment and varies with the mode of transport. Thus, this study attempts to assess the health impacts of air pollution exposure on auto rickshaws and cab drivers. The study was conducted in Delhi using a triangular approach involving a health perception survey, lung function test and in-vehicle monitoring of particulate matter (PM₁, PM_2.5, PM₁₀) concentration to assess the health impacts of air pollution on auto rickshaw and cab drivers. A total of 150 respondents (75 from each occupation) were surveyed, and spirometry was performed for 40 respondents (20 from each occupation). Binary logistic regression showed auto rickshaw drivers were exposed to significantly higher in-vehicle PM concentrations in summers and winters and, thus, had a significantly higher risk of developing respiratory, ophthalmic and dermatological health symptoms (p< 0.05 and relative risk >1). Pulmonary function test showed obstructive lung impairment was reported only among auto rickshaw drivers (6%) and restrictive lung impairment was also more prevalent among auto rickshaw drivers (48%) than cab drivers (33%), suggesting a greater vulnerability of auto rickshaw drivers to respiratory health issues. Lung function impairment was associated with age (p= 0.002). The health and well-being of individuals is a matter of global concern, also highlighted in sustainable development goal no. 3. However, it was observed that neither auto rickshaw drivers nor cab drivers used formal/standard protective measures mainly due to unawareness or unaffordability. The study suggests increasing awareness and formulating guidelines to highlight the use of proper protective measures by these vulnerable groups and specific policy measures to protect outdoor workers like auto rickshaw drivers.

Urinary Mercapturic Acids to Assess Exposure to Benzene and Other Volatile Organic Compounds in Coke Oven Workers

Coke production was classified as carcinogenic to humans by the International Agency for Research on Cancer. Besides polycyclic aromatic hydrocarbons, coke oven workers may be exposed to benzene and other volatile organic compounds (VOCs). The aim of this study was to assess the exposure to several VOCs in 49 coke oven workers and 49 individuals living in the same area by determining urinary mercapturic acids. Active tobacco smoking was an exclusion criterion for both groups. Mercapturic acids were investigated by a validated isotopic dilution LC-MS/MS method. Linear models were built to correct for different confounding variables. Urinary levels of N-acetyl-S-phenyl-L-cysteine (SPMA) (metabolite of benzene), N-acetyl-S-(2-hydroxy-1/2-phenylethyl)-L-cysteine (PHEMA) (metabolite of styrene), N-acetyl-S-(2-cyanoethyl)-L-cysteine (CEMA) (metabolite of acrylonitrile), N-acetyl-S-[1-(hydroxymethyl)-2-propen-1-yl)-L-cysteine and N-acetyl-S-(2-hydroxy-3-buten-1-yl)-L-cysteine (MHBMA) (metabolites of 1,3-butadiene) were 2-10 fold higher in workers than in controls (p < 0.05). For SPMA, in particular, median levels were 0.02 and 0.31 µg/g creatinine in workers and controls, respectively. Among workers, coke makers were more exposed to PHEMA and SPMA than foremen and engine operators. The comparison with biological limit values shows that the exposure of workers was within 20% of the limit values for all biomarkers, moreover three subjects exceeded the restrictive occupational limit value recently proposed by the European Chemicals Agency (ECHA) for SPMA.

Blood pressure in indoor and outdoor workers

INTRODUCTION

The aim of our study is to evaluate the changes in systolic and diastolic blood pressure in two occupational categories: outdoor workers (traffic policemen and environment technicians) and indoor workers.

MATERIALS AND METHODS

The study was conducted comparing the results obtained from three samples of male workers: 175 outdoor traffic policemen, 175 outdoor environment technicians and 175 indoor workers. The outdoor and indoor groups were made comparable by age, length of service, body mass index, alcohol consumption, smoking status.

RESULTS

The mean values of systolic and diastolic blood pressure were found higher in traffic policemen and technicians than in indoor workers, as well as higher values of systolic blood pressure in traffic policemen than in technicians.

CONCLUSIONS

The results suggest that outdoor working affects the blood pressure, contributing to an increased cardiovascular risk.

Effects of air pollution on human health and practical measures for prevention in Iran

Air pollution is a major concern of new civilized world, which has a serious toxicological impact on human health and the environment. It has a number of different emission sources, but motor vehicles and industrial processes contribute the major part of air pollution. According to the World Health Organization, six major air pollutants include particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Long and short term exposure to air suspended toxicants has a different toxicological impact on human including respiratory and cardiovascular diseases, neuropsychiatric complications, the eyes irritation, skin diseases, and long-term chronic diseases such as cancer. Several reports have revealed the direct association between exposure to the poor air quality and increasing rate of morbidity and mortality mostly due to cardiovascular and respiratory diseases. Air pollution is considered as the major environmental risk factor in the incidence and progression of some diseases such as asthma, lung cancer, ventricular hypertrophy, Alzheimer's and Parkinson's diseases, psychological complications, autism, retinopathy, fetal growth, and low birth weight. In this review article, we aimed to discuss toxicology of major air pollutants, sources of emission, and their impact on human health. We have also proposed practical measures to reduce air pollution in Iran.

Spinal and temporo-mandibular disorders in male workers of the State Police

OBJECTIVE

The aims of this study are to evaluate the prevalence of disorders of the lumbar region and the temporo-mandibular district co-morbidity in drivers and workers of the State Police employed for different office activities.

MATERIALS AND METHODS

The study population included 103 drivers as cases and 100 police officers as controls. The study was carried out through questionnaire and clinical evaluation of the spine and temporo-mandibular region.

RESULTS

At clinical examination, the drivers were found to have a higher prevalence (p < 0.05) of both symptoms and clinical signs at the spine and temporo-mandibular joint (TMJ), when compared with the controls. The results also showed a higher prevalence (p < 0.05) of co-morbidity in the two districts among the drivers, when compared with the controls.

CONCLUSIONS

These results confirm that morbidity related to back and TMJ and increase in co-morbidity between the two districts are higher in professional drivers.

Exposure to cadmium in male urban and rural workers and effects on FSH, LH and testosterone

OBJECTIVE

This cross-sectional study was conducted to assess the relationship between exposure to cadmium and circulating reproductive hormone levels in urban and rural male workers.

MATERIALS AND METHODS

Urinary cadmium, blood cadmium, luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone were obtained from 86 non-smoking traffic policemen and 86 subjects working as roadmen in a rural area. All subjects were monitored to evaluate airborne exposure to cadmium.

RESULTS

The mean value of exposure to cadmium was 1.3 ng m(-3) in traffic policemen, while the mean value was less than 0.5 ng m(-3) in roadmen. The mean concentrations of urinary cadmium (1.4 vs. 0.9 μg g(-1) creatinine; p=0.001), blood cadmium (1.1 vs. 0.7 μg l(-1); p=0.000), FSH (2.6 vs. 3.2 μlU ml(-1); p=0.02) and LH (2.6 vs. 3.1 μlU ml(-1); p=0.03) were significantly different between traffic policemen and roadmen. No differences were found in the mean values of testosterone between the two groups. Multiple linear regression models showed associations between (a) urinary cadmium, airborne cadmium, working life, job category and consumption of water from water supply (b) blood cadmium, airborne cadmium and job category (c) the values of FSH and age, working life, job category, urinary cadmium and blood cadmium (d) the values of LH and both the age and working life.

CONCLUSION

The above results must be confirmed by further studies, but they indicate the influence of exposure to the cadmium present in urban air on the circulating FSH, even at low doses.

Correlation between total blood lead values and peripheral blood counts in workers occupationally exposed to urban stressors

The aim of the study was to assess the relationship between occupational exposure to airborne lead (Pb) and alterations in peripheral blood counts in workers of the Municipal Police assigned to different types of outdoor tasks. Then, 337 both male and female subjects were enrolled and divided on the basis of sex, cigarette smoking habit and kind of task. Exposure to airborne Pb, dosage of total blood Pb and peripheral blood count were carried out. A significant positive correlation was detected between the values of total blood Pb and values of plasma reticulocytes (%RET) both in the total sample and for all the classes of the subdivision except for police drivers. Some statistically significant correlations were present but discontinuous for other variables of peripheral blood counts. Results suggest that occupational exposure to low doses of airborne Pb is able to influence lines of the hematopoietic system in exposed workers, with special reference to %RET.