Assessment of environmental tobacco smoke and respirable suspended particle exposures for nonsmokers in Prague using personal monitoring

Objective: Exposures to respirable suspended particles (RSP) and environmental tobacco smoke (ETS) were assessed in Prague, Czech Republic, to determine the range and degree of personal exposure by means of personal monitoring over a 24-h period. Design: Self-reported nonsmokers were randomly selected from a representative sample of the population of Prague. Housewives were recruited into one group, primarily for assessment exposures in the home, and office workers were recruited into a second group for assessment of the contribution from the workplace. Methods: A total of 238 randomly selected nonsmoking subjects collected air samples near their breathing zone by wearing personal monitors for 24 h. Samples collected were analyzed for RSP, nicotine, 3-ethenylpyridine, and ETS particles (using ultraviolet absorbance, fluorescence, and solanesol measurements). Saliva cotinine analyses were also undertaken to confirm the nonsmoking status of the subjects. Results: The most highly exposed subjects in this study were office workers both living and working with smokers. Median time-weighted average exposure concentrations of 60 μg m⁻³ RSP, 16 μg m⁻³ ETS particles, and 1.6 μg m⁻³ nicotine were determined for these subjects, who also had the highest median saliva cotinine level of 2.4 ng ml⁻¹. Housewives living in nonsmoking households were the least exposed subjects in this study, showing levels of 32 μg m⁻³ RSP, 0.17 μg m⁻³ ETS particles, and 0.15 μg m⁻³ nicotine. As based upon median levels of ETS particles and nicotine, no group would potentially inhale or be exposed to more than 10 cigarette equivalents per year (CE/y) and the least exposed would inhale less than 1 CE/y. The most highly exposed (90th percentile levels) nonsmokers in this study, who both worked and lived with smokers, would potentially inhale up to 29 CE/y. Overall, the workplace was estimated to contribute between 45% and 49% of the annual exposure to nicotine and ETS particles, respectively. On the basis of determined saliva cotinine concentrations, a misclassification rate of between 1.7% and 2.5% was calculated. Conclusions: Highest exposures were apparent for office workers both working and living in smoking environments, and our findings suggest a significant contribution to overall ETS particle and nicotine levels from the workplace where smoking takes place. Overall, the rates at which subjects were determined to have misclassified their smoking status in this study were the lowest observed in any of the European cities investigated to date. Clearly, a more sensitive method of analysis for cotinine in body fluids is needed for more accurate determination of the levels expected for nonsmokers. Received: 19 November 1997 / Accepted: 26 February 1998     

Sick-building symptoms in office workers in northeastern France: a pilot study

Study objectives: To verify that sick building symptoms are present in north-eastern France office workers; to try to identify new confounding factors. Methods: The design was that of a cross-sectional study with control group.We studied with the same methods the personnel of an air-conditioned building (n = 425), and of a naturally ventilated building (n = 351). Air temperature and humidity, bacterial and fungal densities were measured by the same technical staff in the two buildings. A standard questionnaire on irritative and respiratory symptoms, personal and family history, and lifestyle was completed by the participants. Results: In univariate analysis, exposure to air-conditioning was associated with an increased prevalence of symptoms (odds ratios-OR-between 1.54 and 2.84). A significant increase in sickness absence was also found among subects working in air-conditioned offices. As a series of factors were suspected to interfere with these associations, logistic regression was applied. This method confirmed exposure to be an independent determinant of 7 symptoms, and also identified two determinants not previously described: a family history of respiratory diseases and “do-it-yourself” activities. In Conclusion: we found the sick building symptoms to be present in a group of French office workers exposed to air-conditioning. We confirmed the influence of a number of confounding factors and described two further confounders – do-it-yourself activities at home and a history of familial respiratory disease.     

Effects of exposure to carbon disulfide (CS2) on electrocardiographic features of ischemic heart disease among viscose rayon factory workers

The objective of the study was to evaluate viscose plant workers for electrocardiographic manifestations resulting from exposure to carbon disulfide (CS₂). A total of 162 workers (118 in an exposure group and 44 in a reference group) were evaluated using a health questionnaire, physical check-up, biochemical analysis of blood samples and electrocardiograms (ECG). The exposure group consisted of workers in the following areas: viscose manufacturing, cellophane processing, ripening, and filament spinning. Reference group workers were from the administrative office, rolling area, pulp processing, and testing office. Only slight differences were found in the biochemical analyses of the two groups, with the exception of sodium (Na) levels. Personal and area sampling results were found to have a high variation due to different locations within the plant and a wide range of manufacturing processes. Highest CS₂ concentrations were found in the ripening area (54.60 ppm) and the filament spinning area (19.60 ppm). Using a multiple logistic regression model to control variables (age, gender, body mass index, duration of employment, cholesterol, smoking, and alcohol), we found a relative risk for ECG abnormalities 4.18 times significantly higher for the exposure group. The authors feel that the installation of an adequate ventilation system could greatly reduce the risk of workers developing CS₂-induced cardiovascular abnormalities. Received: 29 August 1995 / Accepted: 17 January 1997     

Urinary excretion of phenols as an indicator of occupational exposure in the coke-plant industry

Objective: In the present study the relationship between the level of exposure to o-cresol and of 2,4- +2,5-, 3,4-, and 3,5-xylenols and the urinary excretion of their metabolites was examined. The mixed exposure to phenolic derivatives of exposed workers during their work shift was monitored by personal air sampling of the breathing-zone air and by measurements of phenol, o-cresol, and xylenol isomer concentrations in shift-end urine. Methods: The study subjects were 76 men working at a coke plant who were 22–58 years old and 34 nonexposed subjects. Concentrations of phenolic compounds were determined in the breathing-zone air during the work shift, whereas concentrations of phenol, cresol, and xylenol isomers were measured in urine collected after the work shift. Concentrations of phenols in air and urine were determined by gas chromatography with flame-ionization detection. Urine samples were extracted after acid hydrolysis of glucuronides and sulfates by solid-phase extraction. The gas chromatography-mass spectrometry method was applied to identify metabolites in urine samples. Results: The time-weighted average concentrations of phenol, cresol, and xylenol isomers detected in breathing-zone air showed that the exposure level of the workers was relatively low. The geometric mean values were as follows: 0.26 mg/m³ for phenol, 0.09 mg/m³ for o-cresol, 0.13 mg/m³ for p- and m-cresol, and 0.02–0.04 mg/m³ for xylenols at the tar-distillation process. Corresponding urinary concentrations were 10.39, 0.53, and 0.25–0.88 mg/g creatinine for phenol, o-cresol, and xylenol isomers, respectively. The correlation coefficients between the o-cresol and 2,4-, 2,5-, 3,4-, and 3,5-xylenol concentrations measured in urine and in the breathing-zone air were statistically significant, varying in the range of 0.54–0.74 for xylenol isomers and being 0.69 for o-cresol. Conclusion: We have found that the presence of o-cresol and xylenol isomers in urine can be used as a biomarker for phenol exposure. Analysis performed on workers at the tar-distillation process showed that they were exposed to relatively low concentrations of phenolic compounds. Received: 15 October 1996 / Accepted: 5 May 1997     

The integrity of the liver among people environmentally exposed to cadmium at various levels

The objective of the present study was to examine if environmental exposure to cadmium (Cd) had any impact on the integrity of the liver among the general Japanese population. A nationwide survey was conducted in the winter seasons of 1991–1995 in 15 prefectures in Japan to collect 24-h food duplicates, peripheral blood samples, and morning spot urine samples from healthy nonsmoking adult women. The samples were analyzed for Cd by automated graphite furnace atomic absorption spectrometry. In total, 371 women offered food duplicate, blood, and urine samples. The dietary Cd intake was 17.3–79.4 μg/day, the level of Cd in blood was 1.58–3.82 ng/ml, and the urinary Cd concentration was 1.06–4.74 μg/g creatinine as geometric means calculated on a regional group basis. Analyses for correlation with liver function showed no Cd-exposure-related elevation in enzyme levels or reduction in albumin levels' in serum. The distribution of cases with enzyme levels above normal ranges (or below normal in the case of albumin) did not show any dose-related bias. The age of the subject, not the exposure to Cd, was the most influential factor in determining serum enzyme levels. Environmental exposure to Cd has not affected the integrity of the liver among the general population in Japan. Received: 8 August 1996 / Accepted: 8 November 1996     

A critical review of epidemiology studies of trichloroethylene and perchloroethylene and risk of renal-cell cancer

The epidemiology studies of trichloroethylene (TCE) and perchloroethylene (PCE) as they relate to risk of renal-cell cancer are critically reviewed. The studies fall into two basic groups: cohort studies of workers who use TCE or PCE and community-based case-control studies. Issues of bias, confounding, and chance are examined in relation to the studies. There is little evidence of an increased risk of renal-cell cancer and exposure to TCE or PCE. The few studies with elevations in risk suffer from important methodologic shortcomings. Although it is virtually impossible using epidemiology data to rule out conclusively a small increase in risk of renal-cell cancer, the totality of epidemiologic evidence clearly does not support a causal association with TCE or PCE. Future studies of these chemicals must include quantitative evidence of exposure and proper methodologic design, be large-scale in nature to detect small increases in risk, and provide a coherent interpretation of all epidemiology data on these solvents and risk of renal-cell cancer. Received: 17 March 1997 / Accepted: 19 June 1997     

Exposure to extremely-low-frequency electromagnetic fields and radiofrequency radiation: cardiovascular effects in humans

Cardiovascular changes in humans exposed to nonionizing radiation [including extremely-low-frequency electromagnetic fields (ELF EMFs) and radiofrequency radiation (RFR)] are reviewed. Both acute and long-term effects have been investigated. In general, if heating does not occur during exposure, current flow appears to be necessary for major cardiovascular effects to ensue, such as those due to electric shock. Whereas most studies have revealed no acute effect of static or time-varying ELF EMFs on the blood pressure, heart rate, or electrocardiogram waveform, others have reported subtle effects on the heart rate. The possible health consequences of these results are unknown. Regarding long-term effects of ELF EMFs, reports from the former Soviet Union in the early 1960s indicated arrhythmias and tachycardia in high-voltage-switchyard workers. Subsequent studies in Western countries, however, did not confirm these findings. These studies are limited by uncertainties regarding exposure durations and appropriate control groups. Investigations of acute cardiovascular changes in humans purposely exposed to RFR have been limited to studies of magnetic resonance imaging (which, in addition to RFR, involves static and time-varying magnetic fields). It has been concluded that such exposures, as presently performed, are not likely to cause adverse cardiovascular effects. Reports of hypertension in workers potentially exposed to high levels of RFR during accidents are considered to be incidental (due to anxiety and posttraumatic stress). Soviet investigators have also indicated that long-term RFR exposure may result in hypotension and bradycardia or tachycardia. Other researchers, however, have been incapable of replicating these results, and some scientists have attributed the effects to chance variations and mishandling of data. In summary, studies have not yielded any obvious cardiovascular-related hazards of acute or long-term exposures to ELF EMFs or RFR at levels below current exposure standards. Received: 18 July 1996 / Accepted: 29 November 1996     

Urinary cotinine concentration in flight attendants, in relation to exposure to environmental tobacco smoke during intercontinental flights

Objectives: To measure and compare the urinary cotinine concentration (U-cotinine) in non-smoking cabin attendants (C/A) working with the Scandinavian Airlines System, before and after work on intercontinental flights with exposure to environmental tobacco smoke (ETS). Methods: The study material consisted of 24 cabin attendants and one pilot, all volunteers and all without exposure to ETS in the home, working on 15 intercontinental flights. Information on age, gender and occupation was gathered, as well as possible sources of ETS exposure in other places, outside work and during previous flights, during a 3-day period prior to the investigation. Urine samples were taken before departure and after landing, on board, and were kept frozen (−20 °C) until analysis. Cotinine was analyzed by a previously developed gas chromatographic method, using mass spectrometry (MS) with selected-ion monitoring (SIM). The difference in U-cotinine before and after the flight was compared. Moreover, the change in U-cotinine during the flight was related to occupation (work in the forward or aft galley) and observed degree of smoking during each flight. Results: The median U-cotinine was 3.71 μg/g crea; 2.4 μg/l (unadjusted) (interquartile range 2.08–8.67 μg/g crea) before departure, and 6.37 μg/g crea; 7.1 μg/l (interquartile range 3.98–19 μg/g crea) after landing, a significant difference (P < 0.003). C/A in the aft galley had a significantly higher concentration of U-cotinine after landing than subjects working in the front of the aircraft (P=0.01). In C/A working in the aft galley, the median increase of U-cotinine was 3.67 μg/g crea; 3.2 μg/l (interquartile range 0.04–13.8 μg/g crea) during flight. In contrast, those seven subjects working in the forward part of the aircraft had no increase in U-cotinine during the flight (median increase 0.97 μg/g crea; 0.5 μg/l interquartile range 0.27–2.65 μg/g crea). Conclusion: Tobacco smoking in commercial aircraft may cause significant exposure to environmental tobacco smoke among C/A working in the aft galley, despite high air exchange rates and spatial separation between smokers and non-smokers. This agrees with earlier studies, as well as measurements on the aircraft, showing a higher degree of ETS-related air pollution in the aft galley than in the forward galley. The average cotinine concentration in urine was similar to that in other groups with occupational exposure to ETS, e.g., restaurant staff, police interrogators and office workers. Since smoking in commercial aircraft may result in an involuntary exposure to ETS among non-smokers, it should be avoided. Received: 1 February 1999 / Accepted: 29 May 1999     

Occupational and environmental medicine in New York State

New York State (NYS) is home to 7.2% of the population and producer of 8.4% of the gross domestic product of the United States. The history and the current status of occupational and environmental medicine (OEM) research, educational resources, clinical practice patterns, and regulatory framework in NYS are reviewed. Changes anticipated or already taking place in health care financing, clinical practice patterns, occupational safety and health regulations and enforcement, and funding for research and medical education at the national level, are already having an impact in OEM activities in NYS. Received: 11 December 1996 / Accepted: 20 December 1996     

Respiratory health and fluoride exposure in different parts of the modern primary aluminum industry

Objective: The aim of this cross-sectional study was to investigate possible acute and long-term respiratory health effects of work at different working places in the primary aluminum industry. Method: A cross-sectional study was carried out on 78 potroom workers, 24 foundry workers, and 45 carbon-plant workers (n = 147, exposed group), and 56 control workers (watchmen, craftsmen, office workers, laboratory employees) of a modern German prebake aluminum plant. The survey consisted of pre- and postshift spirometric and urinary fluoride measurements. Results: Potroom workers had significantly lower preshift results with regard to forced vital capacity (FVC, 99.5% versus the 107.2% predicted; P < 0.05) and peak expiratory flow (PEF, 85.2% versus the 98.4% predicted; P < 0.01) as compared with controls. In a multiple regression model a small but significant negative correlation was found between postshift urinary fluoride concentrations and FVC, FEV₁, and PEF. Across-shift spirometric changes were observed only in FVC among carbon-plant workers (103.0 ± 13.3% predicted preshift value versus 101.2 ± 13.6% predicted postshift value; P < 0.05). Conclusions: The results suggest that lung function impairment in the modern primary aluminum industry may be only partly due to fluoride exposure and that working in aluminum carbon plants may cause acute lung function changes. Received: 8 July 1998 / Accepted: 31 October 1998     

Benzene in environmental air and human blood

To study the blood benzene levels resulting from environmental and occupational benzene exposure. Methods: Benzene in venous blood was measured in 243 nonoccupationally exposed subjects (“normal” people) and in 167 workers occupationally exposed to benzene. All exposed workers gave blood samples at the end of the work shift and on the following morning before resuming work. Blood benzene was assayed by gas chromatography (GC)-mass spectrometry. Occupational benzene exposure was monitored by environmental personal samplers and measured by GC analysis. Results: The mean occupational benzene exposure for all 167 workers studied was 186 ng/l (58 ppb; range 5–1535 ng/l, 2–500 ppb). Overall, the mean blood benzene level of all workers was 420 ng/l at the end of the shift and 287 ng/l on the morning thereafter. The blood benzene levels measured the morning after turned out to be significantly lower (t = 3.6; P < 0.0001) than those measured at the end of the shift. The mean blood benzene level of the 243 “normal” subjects was 165 ng/l, which was significantly lower than that measured in the workers on the morning thereafter (t=5.8; P < 0.0000001). The mean blood benzene concentration was significantly higher in smokers than in nonsmokers in both the general population (264 versus 123 ng/l) and in the exposed workers. In the group of nonsmoking workers, whose workplace exposure to benzene was lower than 100 ng/l, blood benzene levels were similar (210–202 ng/l) to those measured in the nonsmoking general population (165 ng/l). End-of-shift blood benzene correlated significantly with environmental exposure (y=0.91x + 251; r=0.581; n=162; P < 0.00001). Finally, there was also a significant correlation between blood benzene measured at the end of the shift and that determined on the morning thereafter (y=0.45x + 109; r=0.572; n=156; P < 0.00001). Conclusion: Nonsmoking workers occupationally exposed to benzene at environmental levels lower than 100 ng/l (mean 35 ng/l) and the nonsmoking general population exposed to ubiquitous benzene pollution have similar blood benzene concentrations. This suggests that it is impossible to distinguish between occupational and environmental exposure when the benzene level in the workplace is less than 100 ng/l. Received: 31 December 1997 / Accepted: 4 August 1998     

Ethnic differences in biological monitoring of several organic solvents II. A simulation study with a physiologically based pharmacokinetic model

To improve the reliability of biological monitoring and the development of biological limit values, ethnic differences in the biological monitoring of several organic solvents were studied in Orientals and Caucasians. Six Caucasian and six Oriental volunteers were exposed to each organic solvent in an exposure chamber for 6 h at rest. The exposure concentrations were 50 ppm for perchloroethylene, 50 ppm for styrene, and 100 ppm for m-xylene, respectively. Experimental results were compared with simulation results of a physiologically based pharmacokinetic (PB-PK) model. Differences between Orientals and Caucasians under occupational exposure were also estimated by extrapolation. The simulation results obtained for the Caucasian group showed good agreement with the experimental results. However, the Oriental group did not show good agreement when the same metabolic parameters values applied to Caucasians were used in the PB-PK model. By modification of the metabolic parameters it was possible to get a good fit between the model and the results of the Oriental group. The simulation results obtained for occupational exposure also showed differences in biological levels between the two ethnic groups. Implications of these differences between experimental and simulation results are discussed in the context of the application of biological monitoring and in the development of biological limit values. Received: 14 October 1996 / Accepted: 29 November 1996     

Exposure-response relationships in rhinitis and conjunctivitis caused by methyltetrahydrophthalic anhydride

Objective: To examine exposure-response relationships in the occurrence of symptoms of the eyes and airways in workers exposed to methyltetrahydrophthalic anhydride (MTHPA). Methods: A population of 111 workers from 2 condenser plants (A and B) using epoxy resin with MTHPA underwent a questionnaire survey and serology investigations, and data obtained on 95 subjects in assembly and inspection lines were analyzed for this study. Results: In all, 24 (65%) of 37 workers in plant A and 38 (66%) of 58 workers in plant B had positive MTHPA-specific IgE. The air levels of MTHPA detected in assembly and inspection lines were higher in plant A than in plant B (geometric mean 25.5–63.9  and 4.93–5.49 μg/m³, respectively). IgE-sensitized workers in each plant had significantly (P < 0.05) more complaints regarding the eyes and nose than did unsensitized workers, suggesting that there is an IgE-mediated mechanism in most of these symptoms. The sensitized workers in plant A had higher frequencies for symptoms of the eyes, nose, and pharynx than did those in plant B (P < 0.02). Furthermore, only 15% of persons often displayed work-related symptoms among the 20 symptomatic workers in plant B as compared with 73% of the 26 symptomatic workers in plant A (P < 0.0001). These results can be explained by the difference in the MTHPA levels measured in the lines between the two plants. In plant B the minimal level of MTHPA that was associated with work-related symptoms was 15–22 μg/m³, which was lower than the geometric mean levels detected in assembly and inspection lines in plant A. Conclusions: These results suggest that MTHPA exposure at levels above 15 μg/m³ should be avoided to prevent the development of occupational allergic diseases in most workers. Received: 4 May 1998 / Accepted: 4 August 1998     

Biological monitoring of workers exposed to 4,4′-methylene-bis-(2-orthochloroaniline) (MOCA)

Objective: The objective of the study was to validate a new and simple method to determine MOCA in the urine of exposed workers. Methods: The separation, identification and quantification of urinary MOCA were performed in spiked urines by a sensitive and practical high-performance liquid chromatography (HPLC) method and applied to urine samples of 11 workers occupationally exposed to MOCA; the postshift urinary levels of MOCA in their urine samples with and without hydrolysis, “total” and “free” MOCA respectively, were determined. In addition, we investigated the use of citric or sulfamic acid as preservatives of urine samples. Results: The “total” and “free” MOCA were extracted with isooctane from hydrolysed and nonhydrolysed 20-ml urine samples respectively. After evaporation, the residue was dissolved in 4 ml of 2 · 10⁻² M aqueous hydrochloric acid and analysed by an isocratic HPLC system using both ultraviolet (UV) detection at 244 nm and electrochemical detection working in oxidation mode (0.9 V) with an Ag/AgCl reference electrode. Mobile phase (50% acetonitrile in water containing 0.4% acetate buffer solution pH = 4.6) was used to complete the 20-min analysis. “Free” and “total” MOCA were chromatographed on a reversed-phase C8 column (5 μm; 250 mm × 4 mm). The standard curve of MOCA was linear over the range 5–500 μg/l in human urine. The detection limit was 1 μg/l for a 20-μl injection volume; the repeatability ranged from 5.6 to 1.3% (n = 6) for spiked urines at 5 and 500 μg/l, with a percentage recovery of 94 ± 3%. The reproducibility of the method was 7.3% (n = 4) for spiked urine at 10 μg/l. The use of sulfamic acid as a preservative of urine samples is important to improve the precision and accuracy of the analysis. Conclusion: The results indicate that these analytical procedures using conventional apparatus may be used routinely and reliably with large numbers of urine samples for biological monitoring of the exposure to MOCA. The occupational exposure to MOCA in some factories in France is studied in the second part of this work. Received: 10 November 1998 / Accepted: 25 March 1999     

Determination of N-nitrosodiethanolamine in urine by gas chromatography thermal energy analysis: application in workers exposed to aqueous metalworking fluids

 Objective: The aim of this study was to describe a detailed and validated methodology designed for the analysis of carcinogenic N-nitrosodiethanolamine (NDELA) down to sub-μg/l levels in urine and its application to a number of workers exposed to NDELA-contaminated aqueous metalworking fluids (MWF). Methods: Following a work-up procedure based on solid-phase extraction of NDELA, the urinary extracts were analysed without derivatization by gas chromatography on a polar wide-bore column with chemiluminescent detection using a thermal energy analyser (TEA). N-Nitroso-(2-hydroxypropyl)amine was used as an internal standard. The method was applied to 12 workers using “nitrite-free” or “nitrite-formulated” MWF and to 15 unexposed subjects. The NDELA content of the MWF was also determined using a similar, but simpler method able to easily quantify NDELA down to at least 0.1 mg/l. Results: Contamination by NDELA traces of some chemicals used for the sample preparation, particularly ethyl formate, must be carefully checked since it can give rise to false-positive results of up to 1 or 2 μg/l. The response was linear in the range of 0–500 μg/l. Between 0.5 and 10 μg/l, the recovery rate was close to 95%, while repeatability ranged from 12.5 to 6.4% (n = 5). The detection limit was 0.3 μg/l (Signal/noise = 3). No detectable NDELA could be observed in the control workers. There was no significant increase in NDELA levels at the end of shift spot samples from an exposed worker over 1 week. Higher NDELA concentrations were found in two workers (4.3 and 10.7 μg/l) exposed to “nitrite-formulated” fluids (contaminated with 65 and 18 mg NDELA per l, respectively) than in nine workers (range, 0.4–1.3 μg/l exposed to “nitrite-free” fluids with lower levels of NDELA (range, 0.5–6.6 mg/l). Conclusion: The detailed methodology described in this work and applied to a limited industrial situation was found to be suitable for monitoring NDELA in the urine of workers exposed to aqueous MWF. A much larger screening has been undertaken with the aim of obtaining better information on the real exposure of workers sometimes exposed to “nitrite-formulated” fluids that are still used. Received: 8 December 1998 / Accepted: 3 April 1999     

Association between blood levels of lead, blood pressure and risk of diabetes and heart disease in workers

Background: Previous studies have supported the association between high levels of blood lead levels (BLL) and elevated blood pressure. In addition, significant correlations between BLL and a variety of risk factors for blood pressure and diabetes mellitus have been well-established. Objective: To examine the relationship between BLL, blood pressure and diabetes as well as other selected social and biochemical factors, among workers in the United Arab Emirates (UAE). Methods: This comparative study included 110 industrial workers (exposed to lead in the workplace) and 110 non-industrial workers (not exposed); all were recruited in the city of Al-Ain, Abu-Dhabi Emirate, UAE and the groups were evenly matched for age, gender and nationality. Results: The industrial workers had a significantly higher mean of BLL (median 81 and geometric mean (GM) 62 μg/dl) than did non-industrial workers (median 11 and GM 13 μg/dl). In the present study, the lead-exposed group also had significantly higher blood lead levels, body-mass index (BMI), systolic and diastolic blood pressures, fasting blood glucose and plasma levels of total cholesterol, lactate dehydrogenase and uric acid than did the non-exposed group. Furthermore a significant correlation between BLL and systolic blood pressure was observed. Conclusion: The study supports the hypothesis of a positive association between lead exposure, high blood pressure and risk of diabetes and heart disease. Received: 11 July 2000 / Accepted: 5 January 2001     

Biological monitoring of environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the vicinity of a creosote impregnation plant

Objective: This study was undertaken to evaluate the environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in nonsmoking adult subjects living in the vicinity of a creosote impregnation plant in Delson, Canada. Urinary metabolites of naphthalene, α- and β-naphthol, and pyrene metabolite 1-hydroxypyrene (1-OHP), were used as biomarkers of exposure. Methods: Morning and evening urine samples were collected in mid-August from 30 exposed individuals living at a distance of 50–360 m downwind of the plant and from a control group in the adjoining municipality residing at a distance of 1.9–2.7 km upwind of the plant. Metabolites were measured by gas chromatography/mass spectrometry. Results: Excretion values of α- and β-naphthol were significantly higher in the exposed group than in controls (P < 0.04), after accounting for possible confounding variables by multivariate analyses. The respective geometric mean concentrations (5th and 95th percentiles) of α-naphthol for the exposed and nonexposed groups were 2.04 (0.55–6.00) and 1.37 (0.39–7.02) μmol/mol creatinine for evening samples, and 2.49 (0.77–8.43) and 1.17 (0.37–6.88) μmol/mol creatinine for morning samples. Corresponding values for β-naphthol were 1.78 (0.82–3.67) and 1.36 (0.63–5.07) μmol/mol creatinine for evening samples, and 1.94 (1.03–4.96) and 1.08 (0.49–5.05) μmol/mol creatinine for morning samples. On the other hand, no significant difference in 1-OHP excretion was observed between the exposed and the control group (P>0.5). The respective geometric mean concentrations (5th and 95th percentiles) of 1-OHP for these groups were 0.05 (0.01–0.17) and 0.06 (0.01–0.48) μmol/mol creatinine for evening samples, and 0.05 (0.02–0.12) and 0.05 (0.01–0.42) μmol/mol creatinine for morning samples. Conclusions: The measurement of α- and β-naphthol urinary concentrations appears to be an approach sufficiently sensitive to reveal differences in low exposure levels of volatile PAHs due to creosote impregnation plant emissions. However, uptake of pyrene due to the plant was too small to contribute significantly to 1-OHP excretion. Received: 13 June 2000 / Accepted: 21 April 2001     

Development of the fluorometric ELISA method for determination of α 1-microglobulinuria in a cadmium-polluted area in Japan

Objectives: To evaluate the usefulness of a newly developed fluorometric enzyme-linked immunosorbent assay (fluorometric ELISA) method for quantification of α1-microglobulin (α1-m, protein HC) in an epidemiological study. Methods: Urinary α1-m in 37 female inhabitants in a cadmium-polluted area, including seven cases with Itai-itai disease, and ten inhabitants in a non-polluted area in Japan were examined. The α1-m was measured by both the fluorometric ELISA and a commercially available enzyme immunoassay (EIA) method to evaluate correlation of the two measurements. Concentration of β2-microglobulin (β2-m) was also determined in the same samples. Results: The detection limit of this method was 3 ng/ml or less of α1-m. A significant, high positive correlation was obtained between the α1-m concentrations measured with the fluorometric ELISA and that of EIA (r=0.95, P < 0.0001). A significant association was also shown between the α1-m and β2-m concentrations in the urine samples. The concentrations of urinary α1-m of the inhabitants in the cadmium-polluted area (mean: 6.21 mg/l, 95% confidence interval (95% CI): 4.06–9.50 mg/l) were significantly higher than those of the reference area (mean: 2.19 mg/l, 95% CI: 1.90–2.67 mg/l). The urinary α1-m level of the Itai-itai patients was shown to be highest at 39.63 mg/l (95% CI: 28.27–55.55 mg/l). When the cut-off value of 10 mg/l was employed, α1-m had a sensitivity of 100% and specificity of 100% for Itai-itai disease. Conclusion: These results suggest that this fluorometric ELISA is a useful tool to determine urinary α1-m in the epidemiological survey of renal tubular dysfunction, especially in the cadmium-polluted area of Japan. Received: 17 July 2000 / Accepted: 12 April 2001     

Albumin, transferrin and α2-macroglobulin in bronchoalveolar lavage fluid following exposure to organic dust in healthy subjects

Objectives: The purpose of the present study was to investigate leakage of plasma proteins in connection with the inflammatory airway reaction following exposure to dust in a pig house. Inhalation of swine-house dust causes intense inflammation with influx of inflammatory cells, predominantly neutrophils, into the airways. The aim of the study was to compare the concentration of three different proteins in bronchoalveolar lavage (BAL) fluid as markers for the inflammation. Methods: In twenty healthy, non-allergic, non-smokers, not previously exposed to farm dust, BAL was performed ≈2 weeks before and 24 h after 3 h of exposure to swine dust in a swine-confinement building. Differential cell count and protein concentration were assessed in BAL fluid. Albumin (66.5 kDa) and α₂-macroglobulin (720 kDa) were quantified by the use of enzyme-linked immunosorbent assay (ELISA) techniques, and transferrin (80 kDa) by zone immunoelectrophoresis assay. The coefficient of variation for repeated protein measurements was <9%. Results: α₂-Macroglobulin concentration increased six-fold, from 68.0 (36.1–99.9) μg/l, mean (95% CI) before exposure to 411.2 (254.0–568.4) μg/l after exposure (P < 0.001). Transferrin and albumin increased from 19.7 (16.2–23.1) mg/l and 1.8 (1.4–2.2) mg/l, 2.6 and 1.9 times, respectively (P < 0.001). There was significant correlation between the exposure-induced increased protein levels in BAL fluid, although α₂-macroglobulin was a better discriminator of pre- and post-exposure concentrations than were albumin and transferrin. There was a significant correlation between the exposure-induced BAL-fluid neutrophilia and the increase in α₂-macroglobulin and transferrin, but not for albumin. This correlation was found only when pre- and post- differences, but not ratios, of plasma proteins were compared. Conclusions: The levels of plasma proteins increased in BAL fluid following exposure to swine-house dust. α₂-Macroglobulin was a better marker of this plasma leakage than were albumin and transferrin. Received: 25 July 2000 / Accepted: 10 November 2000     

Cognitive functions in workers exposed to toluene: evaluation at least 48 hours after removal from exposure

Objectives: Long-term exposure to toluene may result in subtle impairment of cognitive functions. However, it is not clear whether this impairment is due to the presence of the solvent in the body or if it persists after its elimination from blood. The aim of this study is to compare cognitive functions between toluene-exposed workers (at least 48 h after removal from exposure) and non-exposed workers. Methods: Seventy-two workers exposed for at least 5 years to toluene (9 to 467 ppm) completed a questionnaire and psychometric tests. The results were compared with those of 61 non-exposed workers. An alveolar air sample was taken just before the tests to ensure the absence of toluene. Results: Results of the vocabulary test were slightly better in exposed (correct words: 21 ± 0.6) than in non-exposed workers (19 ± 0.8) (P < 0.05). No differences were found for simple reaction time, digit symbol, digit span, continuous tracking test, color word and switching attention test. Conclusions: The results of this study do not support the notion of the persistence of cognitive effects of toluene after elimination of the solvent from blood. Received: 5 June 2000 / Accepted: 9 December 2000