Upper reference limits for biomarkers of exposure to aromatic diisocyanates

Objectives: The objectives of this study were to determine the levels of 2,4-toluenediamine, 2,6-toluenediamine, 1,5-naphthtalenediamine and 4,4-methylenediphenyldianiline in hydrolyzed urine and plasma for occupationally unexposed workers and to calculate upper reference limits (URLs). These analytes are biomarkers of exposure to 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (2,4-TDI and 2,6-TDI), 1,5-naphtalene diisocyanate (NDI) and 4,4-methylenediphenyl diisocyanate (MDI), respectively. Methods: The biomarker levels were determined in urinary and plasma samples obtained from 121 occupationally unexposed workers. Based on these biomarkers levels and the biomarker levels in an occupationally exposed group of workers, URLs were calculated. The method used for these calculations was based on the receiver operator characteristic (ROC) curve method technique, and the URLs were set at the optimum of sum of sensitivity and specificity. Results: The URLs for the different diisocyanates were calculated to be in the range of 0.1–0.5 g/L. Occupationally unexposed workers had detectable biomarker levels of the diisocyanates investigated. Especially abundant was the biomarkers of MDI which were found in 97% of both urinary and plasma samples. For the other biomarkers, 0–15% of the unexposed workers had detectable levels. The detected levels were mostly close to the limit of detection (LOD), but urinary levels of biomarkers of MDI up to 60 times the LOD were found. The sensitivities and specificities for classification of the workers as occupationally exposed or not, were in the range of 88–100% and 97–100%, respectively. Conclusions: The URLs were calculated that may be applicable when screening for occupational exposure. A worker with a biomarker level above the URL will be classified as occupationally exposed. Biomarkers of aromatic diisocyanates, especially biomarkers of MDI, were present among occupationally unexposed workers, but the source and nature of the exposure is unknown.     

Validity of new biomarkers of internal dose for use in the biological monitoring of occupational and environmental exposure to low concentrations of benzene and toluene

Objectives

This study analyzes the validity of new, more sensitive and specific urinary biomarkers of internal dose, namely, urinary benzene for benzene and urinary toluene and S-benzylmercapturic acid (SBMA) for toluene, to assess their efficacy when compared to traditional biomarkers for biological monitoring of occupational exposure to low concentrations of these two toxic substances.

Methods

Assessment was made of 41 workers occupationally exposed to benzene and toluene, 18 fuel tanker drivers and 23 filling-station attendants, as well as 31 subjects with no occupational exposure to these toxic substances (controls). Exposure to airborne benzene and toluene was measured using passive Radiello^® personal samplers worn throughout the work shift. In urine samples collected from all subjects at the end of the workday, both the traditional and the new internal dose biomarkers of benzene and toluene were assessed, as well as creatinine so as to apply suitable adjustments.

Results

Occupational exposure to benzene and toluene resulted significantly higher in the fuel tanker drivers than the filling-station attendants, and higher in the latter than in controls. Significantly higher concentrations of t,t-muconic acid (t,t-MA), S-phenylmercapturic acid (SPMA), urinary benzene, SBMA and urinary toluene were found in the drivers than the filling-station attendants or the controls. Instead, urinary phenol and hippuric acid were not different in the three groups. In the entire sample, airborne benzene and toluene values were significantly correlated, as were the respective urinary biomarkers, showing coefficients ranging from 0.36 to 0.98. Subdividing the subjects by smoking habit, higher coefficients were evident in non-smokers than in smokers; at multiple regression analysis t,t-MA, SPMA and urinary benzene and toluene were dependent on the number of cigarettes smoked daily and on airborne benzene and toluene, respectively. Instead, SBMA was dependent only on airborne toluene.

Conclusions

Our research confirmed the validity of t,t-MA and SPMA for use in the biological monitoring of exposure to low concentrations of benzene. Urinary benzene showed comparable validity to SPMA; both parameters are affected by smoking cigarettes in the hours before urine collection, so it is best to ask subjects to refrain from smoking for 2 h before urine collection. Urinary toluene was found to be a more specific biomarker than SBMA.     

Renal impairment caused by chronic occupational chromate exposure

Purpose

To determine the nephritic toxicity of chromate after chronic occupational exposure.

Methods

The environmental contamination was assessed by measuring the chromium (Cr) in 8-h airborne sampler. The integrated level of Cr was determined by Cr concentrations in the whole blood (WB-Cr) and the urine (U-Cr). The renal glomerular and tubule impairment was evaluated by determination of cystatin C (Cys-C) in the serum and microalbumin (mALB), urinary beta₂-microglobulin (??₂M), N-acetyl-beta-d-glucosaminidase (NAG) activity in the urine.

Results

The mean occupational exposure time to Cr was 12.86?years with average daily air level of 27.13???g/m³ comparing to 0.11???g/m³ of the background level. The WB-Cr and U-Cr were 23.49???g/L and 17.41???g/g creatinine (Cre), respectively in the chromate-exposed workers comparing to 3.32???g/L and 1.52???g/g Cre in the controls. The serum Cys-C and urinary mALB were significantly increased in the chromate-exposed workers. Exposure to Cr seems to induce an enhanced level of urinary NAG activity and ??₂M concentration. The increased serum Cys-C concentration was positively correlated with the level of serum Cre. The U-Cr was positively correlated to the concentrations of urinary mALB, ??₂M, and the activity of NAG.

Conclusions

Chronic occupational exposure to chromate causes comprehensive renal impairment though more severity could occur in the tubule than in the glomeruler.     

Electronic noses for monitoring benzene occupational exposure in biological samples of Egyptian workers

Objectives

Benzene is commonly emitted in several industries, leading to widespread environmental and occupational exposure hazards. While less toxic solvents have been substituted for benzene, it is still a component of petroleum products and is a trace impurity in industrial products resulting in continued higher occupational exposures in industrial settings in developing countries.

Materials and Methods

We investigated the potential use of an electronic nose (e-nose) to monitor the headspace volatiles in biological samples from benzene-exposed Egyptian workers and non-exposed controls. The study population comprised 150 non-smoking male workers exposed to benzene and an equal number of matching non-exposed controls. We determined biomarkers of benzene used to estimate exposure and risk including: benzene in exhaled air and blood; and its urinary metabolites such as phenol and muconic acid using gas chromatography technique and a portable e-nose.

Results

The average benzene concentration measured in the ambient air of the workplace of all studied industrial settings in Alexandria, Egypt; was 97.56±88.12 μg/m³ (range: 4.69–260.86 μg/m³). Levels of phenol and muconic acid were significantly (p < 0.001) higher in both blood and urine of benzene-exposed workers as compared to non-exposed controls.

Conclusions

The e-nose technology has successfully classified and distinguished benzene-exposed workers from non-exposed controls for all measured samples of blood, urine and the exhaled air with a very high degree of precision. Thus, it will be a very useful tool for the low-cost mass screening and early detection of health hazards associated with the exposure to benzene in the industry.     

Association between a biomarker of exposure to polycyclic aromatic hydrocarbons and semen quality

Objectives

Growing evidence supports the reproductive and developmental toxicity of polycyclic aromatic hydrocarbons (PAHs) from prenatal and postnatal exposure, but the results of epidemiological studies regarding harmful effects of PAHs exposure on male reproductive system still remain limited and inconclusive. The aim of the present study was to investigate the relationship between 1-hydroxypyrene, a biomarker of polycyclic aromatic hydrocarbons exposure and semen quality.

Materials and Methods

The study population consisted of 277 men attending an infertility clinic for diagnostic purposes and having normal semen concentration of 20–300 mln/ml or slight oligozoospermia (semen concentration: 15–20 mln/ml) (WHO 1999). All the men were healthy and under 45 years of age. All participants were interviewed and provided a semen sample. The interview included questions concerning demographics, socio-economic status, medical history related to past diseases which may have an impact on semen quality, lifestyle factors and occupational information. Concentrations of 1-hydroxypyrene (1-OHP) in the urine samples were analyzed using high performance liquid chromatography (HPLC).

Results

A positive association was found between the level of 1-OHP in urine and sperm neck abnormalities as well as the percentage of static sperm cells (p = 0.001, p = 0.018, respectively). Additionally, exposure to PAHs measured by 1-OHP in urine decreased semen volume and the percentage of motile sperm cells (p = 0.014, p = 0.0001, respectively).

Conclusions

Presented findings indicate that the environmental level of PAHs exposure adversely affects male semen quality. The future large-scale studies should incorporate different biomarkers to generate a more accurate and full assessment of the effects of PAHs exposure on male fertility.     

Accidental exposure to polychlorinated biphenyls (PCB) in waste cargo after heavy seas. Global waste transport as a source of PCB exposure

Objectives

After cargo with PCB-containing transformer oil waste was damaged in heavy seas, the vessel crew exposed to PCB developed itching and acne-form eruption of the skin. The objective of our study was to analyse this work-related incident and its effects on health.

Methods

Air and wipe test samples were taken in the ship for analysis of PCB (28/52/101/138/153/180); clinical investigations of all seafarers (n = 6) included lung function, chest X-ray, clinical chemistry and biomonitoring (plasma PCBs, chlorophenols in urine) measured after a latency of 7 weeks. The biomonitoring data were adjusted according to age-related reference values and validated against controls (n = 96).

Results

Biomonitoring showed elevated PCB-28-/52/-102/-138 congeners (mean 1.16/0.91/136, ∑PCB: 5.82 μg/l), which correlates with the dust samples from the cargo hold (∑PCB. 9,440 mg/m²) and with 6.1 and 5.0 μg/m³ in stern and bow cargo air samples. IgE elevation in two seafarers and substantial blood sedimentation rate increase with anaemia or pulmonary emphysema were unlikely to be caused by PCB exposure. Although two members showed slightly elevated airway resistance values, other lung function parameters were normal and reactive airways dysfunction syndrome due to PCBs could be excluded. Elevated chlorophenols in urine could contribute to the manifestation of chloracne.

Conclusions

PCB-52/-101/-138 found in plasma and in air samples confirm exposure to PCB. Acne-form skin eruptions were from occupational exposure to polychlorinated biphenyls in the spilt transformer oil. There were no other abnormal findings in medical and clinical examinations that could be attributed to PCBs. This does not exclude possible long-term effects.     

Medicine students and exposure to environmental tobacco smoke

Objective

Although medicine students express positive attitudes toward providing lifestyle counseling, they require more instruction in many areas of health behavior in order to be helpful to their patients. The presented study included the students’ questionnaires analysis regarding their lifestyle and exposure to tobacco smoke. The aim of this study was to examine students’ exposure to chosen xenobiotics by determination of selected biomarkers in urine samples, which underlay the basis for exposure assessment towards tobacco smoke.

Materials and Methods

The investigated group consisted of first- and second-year medicine students from the Silesian Medical University (N = 133). Data obtained from a questionnaire survey was compared with the results of chosen biomarkers determined in urine samples. The analyses of the main nicotine metabolites were carried out firstly with use of ELISA, followed by the TLC technique with densitometry.

Results

According to questionnaires, every third student examined was exposed to passive smoking. The mean concentration of the main nicotine metabolites determined by ELISA in urine samples of smoking students was 1293.52±396.70 μg/g creatinine. The results of the TLC analysis in the group of smoking students were as follows: for cotinine ? 523.10±68.10 μg/g creatinine and for trans-3’-hydroxycotinine ? 653.81±62.30 μg/g creatinine.

Conclusions

Medicine students, regardless of their area of study, are a highly-exposed part of the population to tobacco smoke, not only actively but also passively. Tobacco smoke exposure can be assessed by ELISA as a screening method as well as by more specific TLC technique with densitometry.     

Toxicokinetic study of pyrrole adducts and its potential application for biological monitoring of 2,5-hexanedione subacute exposure

Purpose

The formation of pyrrole adducts might be responsible for peripheral nerve injury caused by n-hexane, but there is not an effective biomarker for monitoring occupational exposure of n-hexane. The current study was designed to investigate the changes of pyrrole adducts in serum and urine of rats exposed to 2,5-hexanedione (2,5-HD) and analyze the correlation between pyrrole adducts and 2,5-HD.

Methods

Two groups of male Wistar rats (n = 8) were administered a single dose of 200 and 400 mg/kg 2,5-HD (i.p.), and another two groups (n = 8) were given daily dose of 200 and 400 mg/kg 2,5-HD (i.p.) for 5 days. Pyrrole adducts and 2,5-HD in serum and urine were determined, at different time points after dosing, using Ehrlich’s reagent and gas chromatography, respectively.

Results

The levels of pyrrole adducts in serum accumulated in a time-dependant manner after repeated exposure to 2,5-HD, while pyrrole adducts in urine, and 2,5-HD in serum and urine were kept stable. The half-life times (t _1/2) of 2,5-HD and pyrrole adducts in serum were 2.27 ± 0.28 and 25.3 ± 3.34 h, respectively. Furthermore, the levels of pyrrole adducts in urine were significantly correlated with the levels of 2,5-HD in serum (r = 0.736, P < 0.001) and urine (r = 0.730, P < 0.001), and the levels of pyrrole adducts in serum were correlated with the cumulative dosage of 2,5-HD (r = 0.965, P < 0.001).

Conclusion

The results suggested that pyrrole adducts in serum and urine might be markers of chronic exposure to n-hexane or 2,5-HD.     

Environmental cadmium exposure and osteoporosis: a review

Objectives

To review the published literature investigating the association between cadmium exposure and osteoporosis.

Methods

A review of published peer-reviewed literature based on a priori criteria was completed. Odds ratios (OR) were abstracted or estimated from observational studies to calculate a pooled OR using inverse variance weighted random effects models.

Results

The review identified seven studies with a pooled OR of OR = 2.22 (95 % CI: 1.16, 4.28) [I ² = 54.8 % (p < 0.05)] (comparing highest urine cadmium category to lowest). In women over the age of 50 years, the pooled OR was 1.82 (95 % CI: 1.63, 2.02) [I ² = 73.1 % (p < 0.05)]. A dose response evaluation (six studies) suggested increasing odds for osteoporosis with increasing urine cadmium levels.

Conclusions

This review detected an association between cadmium exposure and the occurrence of osteoporosis in a small number of cross-sectional studies which requires confirmation in using prospective study design.     

Prevalence of exposure to occupational risks during pregnancy in Spain

Objectives

We describe reported exposures to main categories of occupational agents and conditions in Spanish pregnant workers.

Methods

Women were recruited at 12th week of pregnancy from main public gynaecological consults to be included in the INMA Spanish cohorts study (n?=?2,058). Through personal interviews with structured questionnaires, information on working situation and working conditions during pregnancy was obtained.

Results

Fifty percent of the women reported frequent exposure to physical load (standing, heavy lifting) and 45?% reported exposure to three or more indicators of job strain. Exposure to at least one physical agent (noise, vibrations, etc.) affected 25?% of the women. Exposure to chemicals was reported by 20?% of the women, mostly including solvents and cleaning products. Eight percent of the women worked at night shifts. Job strain was more prevalent in office workers and industrial operators. Industrial workers showed the highest prevalence of exposure to chemical and physical pollutants.

Conclusions

Our data suggest that working conditions of pregnant women may need increased control in Spain.     

Carbon and nitrogen isotopic ratios of urine and faeces as novel nutritional biomarkers of meat and fish intake

Purpose

Meat and fish consumption are associated with changes in the risk of chronic diseases. Intake is mainly assessed using self-reporting, as no true quantitative nutritional biomarker is available. The measurement of plasma fatty acids, often used as an alternative, is expensive and time-consuming. As meat and fish differ in their stable isotope ratios, δ¹³C and δ¹⁵N have been proposed as biomarkers. However, they have never been investigated in controlled human dietary intervention studies.

Objective

In a short-term feeding study, we investigated the suitability of δ¹³C and δ¹⁵N in blood, urine and faeces as biomarkers of meat and fish intake.

Methods

The dietary intervention study (n = 14) followed a randomised cross-over design with three eight-day dietary periods (meat, fish and half-meat–half-fish). In addition, 4 participants completed a vegetarian control period. At the end of each period, 24-h urine, fasting venous blood and faeces were collected and their δ¹³C and δ¹⁵N analysed.

Results

There was a significant difference between diets in isotope ratios in faeces and urine samples, but not in blood samples (Kruskal–Wallis test, p < 0.0001). In pairwise comparisons, δ¹³C and δ¹⁵N were significantly higher in urine and faecal samples following a fish diet when compared with all other diets, and significantly lower following a vegetarian diet. There was no significant difference in isotope ratio between meat and half-meat–half-fish diets for blood, urine or faecal samples.

Conclusions

The results of this study show that urinary and faecal δ¹³C and δ¹⁵N are suitable candidate biomarkers for short-term meat and fish intake.     

A review of mercury exposure among artisanal small-scale gold miners in developing countries

Purpose

Extraction of gold using mercury has been a way out of poverty for millions of people in developing countries. Artisanal small-scale gold mining (ASGM) has expanded during the last decades and is often carried out under primitive conditions. Thus, workers in this industry may be exposed to high levels of mercury and suffer from toxic effects from mercury exposure. The objective of this review was to provide an outline of the studies available on elemental mercury exposure among artisanal small-scale gold miners.

Methods

Searching the PubMed and Embase databases, 26 studies with a total of 3,005 exposed subjects and 442 controls across 14 different developing countries were found. Urine mercury levels were used as biomarkers of exposure.

Results

In general, the urine mercury levels were elevated and a considerable proportion of workers had urine mercury levels above existing guidelines. Exposed subjects were stratified into residents, miners, millers, smelters, and refiners, who by work task content were expected to be increasingly exposed to mercury. This group order did show a clear trend of increasing mercury levels. Mercury levels differed substantially between studies. Possible explanations include dissimilarities in gold extraction methods, use of protective devices, and selection of participants.

Conclusions

This review provides evidence that artisanal gold miners and residents of the mining sites are exposed to mercury vapour to an extent where acute and long-term toxic effects of mercury are likely. Interventions aimed at reducing exposure and emission of mercury from ASGM are needed.     

Biomarkers of chlorpyrifos exposure and effect in Egyptian cotton field workers

Background

Chlorpyrifos (CPF), a widely used organophosphorus pesticide (OP), is metabolized to CPF-oxon, a potent cholinesterase (ChE) inhibitor, and trichloro-2-pyridinol (TCPy). Urinary TCPy is often used as a biomarker for CPF exposure, whereas blood ChE activity is considered an indicator of CPF toxicity. However, whether these biomarkers are dose related has not been studied extensively in populations with repeated daily OP exposures.

Objective

We sought to determine the relationship between blood ChE and urinary TCPy during repeated occupational exposures to CPF.

Methods

Daily urine samples and weekly blood samples were collected from pesticide workers (n = 38) in Menoufia Governorate, Egypt, before, during, and after 9–17 consecutive days of CPF application to cotton fields. We compared blood butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) activities with the respective urinary TCPy concentrations in each worker.

Results

Average TCPy levels during the middle of a 1- to 2-week CPF application period were significantly higher in pesticide applicators (6,437 μg/g creatinine) than in technicians (184 μg/g) and engineers (157 μg/g), both of whom are involved in supervising the application process. We observed a statistically significant inverse correlation between urinary TCPy and blood BuChE and AChE activities. The no-effect level (or inflection point) of the exposure–effect relationships has an average urinary TCPy level of 114 μg/g creatinine for BuChE and 3,161 μg/g creatinine for AChE.

Conclusions

Our findings demonstrate a dose–effect relationship between urinary TCPy and both plasma BuChE and red blood cell AChE in humans exposed occupationally to CPF. These findings will contribute to future risk assessment efforts for CPF exposure.     

Lack of association between occupational exposure to diesel exhaust and risk of pancreatic cancer: a systematic evaluation of available data

Purpose

To review epidemiologic studies on risk of pancreatic cancer and occupational exposure to diesel exhaust.

Methods

A literature search was conducted, and data were abstracted in a systematic fashion. Comparable results were combined using a random-effects meta-analysis.

Results

Twenty-six studies were included in the review, including five studies based on routine statistics, 11 case–control studies [meta-relative risk (RR) of three estimates for diesel exhaust exposure 0.9; 95 % confidence interval (CI) 0.5, 1.6] and ten cohort studies (meta-RR of their results: 1.03; 95 % CI 0.93, 1.13). Few studies reported results according to duration of exposure or other quantitative measures; no consistent pattern emerged.

Conclusions

The overall evidence from studies on occupational exposure to diesel exhaust and risk of pancreatic cancer leads to the conclusion of the absence of such association.     

Occupational Lead Exposure and Associations with Selected Cancers: The Shanghai Men’s and Women’s Health Study Cohorts

Background

Epidemiologic studies of occupational lead exposure have suggested increased risks of cancers of the stomach, lung, kidney, brain, and meninges; however, the totality of the evidence is inconsistent.

Objective

We investigated the relationship between occupational lead exposure and cancer incidence at the five abovementioned sites in two prospective cohorts in Shanghai, China.

Methods

Annual job/industry-specific estimates of lead fume and lead dust exposure, derived from a statistical model combining expert lead intensity ratings with inspection measurements, were applied to the lifetime work histories of participants from the Shanghai Women’s Health Study (SWHS; n = 73,363) and the Shanghai Men’s Health Study (SMHS; n = 61,379) to estimate cumulative exposure to lead fume and lead dust. These metrics were then combined into an overall occupational lead exposure variable. Cohort-specific relative hazard rate ratios (RRs) and 95% confidence intervals (CIs) comparing exposed and unexposed participants were estimated using Cox proportional hazards regression and combined by meta-analysis.

Results

The proportions of SWHS and SMHS participants with estimated occupational lead exposure were 8.9% and 6.9%, respectively. Lead exposure was positively associated with meningioma risk in women only (n = 38 unexposed and 9 exposed cases; RR = 2.4; 95% CI: 1.1, 5.0), particularly with above-median cumulative exposure (RR = 3.1; 95% CI: 1.3, 7.4). However, all 12 meningioma cases among men were classified as unexposed to lead. We also observed non-significant associations with lead exposure for cancers of the kidney (n = 157 unexposed and 17 ever exposed cases; RR = 1.4; 95% CI: 0.9, 2.3) and brain (n = 67 unexposed and 10 ever exposed cases; RR = 1.8; 95% CI: 0.7, 4.8) overall.

Conclusions

Our findings, though limited by small numbers of cases, suggest that lead is associated with the risk of several cancers in women and men.

Citation

Liao LM, Friesen MC, Xiang YB, Cai H, Koh DH, Ji BT, Yang G, Li HL, Locke SJ, Rothman N, Zheng W, Gao YT, Shu XO, Purdue MP. 2016. Occupational lead exposure and associations with selected cancers: the Shanghai Men’s and Women’s Health Study cohorts. Environ Health Perspect 124:97–103; http://dx.doi.org/10.1289/ehp.1408171     

Occupational exposure to airborne mercury during gold mining operations near El Callao, Venezuela

Objective: The National Institute for Occupational Safety and Health (NIOSH) recently conducted a cross–sectional study during gold mining operations near El Callao, Venezuela. The purpose of the study was to assess mercury exposures and mercury-related microdamage to the kidneys. The study consisted of concurrent occupational hygiene and biological monitoring, and an examination of the processing techniques employed at the different mining facilities. Mercury was used in these facilities to remove gold by forming a mercury-gold amalgam. The gold was purified either by heating the amalgam in the open with a propane torch or by using a small retort. Methods: Thirty-eight workers participated in this study. Some participants were employed by a large mining company, while others were considered “informal miners” (self-employed). Mercury exposure was monitored by sampling air from the workers' breathing zones. These full-shift air samples were used to calculate time-weighted average (TWA) mercury exposure concentrations. A questionnaire was administered and a spot urine sample was collected. Each urine sample was analyzed for mercury, creatinine, and N-acetyl-ß-d-glucosaminidase (NAG). Results: The range for the 8-h TWA airborne mercury exposure concentrations was 0.1 to 6,315?μg/m³, with a mean of 183?μg/m³. Twenty percent of the TWA airborne mercury exposure measurements were above the NIOSH recommended exposure limit (REL) of 50?μg/m³, and 26% exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 25?μg/m³. The mean urine mercury concentration was 101?μg/g creatinine (μg/g-Cr), and the data ranged from 2.5 to 912?μg/g-Cr. Forty–two percent of the study participants had urine mercury concentrations that exceeded the ACGIH biological exposure index (BEI) of 35?μg/g-Cr. Urinary NAG excretion is considered a biological marker of preclinical, nonspecific microdamage to the kidney's proximal tubule cells. The mean urine NAG concentration was 3.6 International Units/g-Cr (IU/g-Cr) with a range of 0.5 to 11.5?IU/g-Cr. Three workers had urine NAG levels in excess of the reference values. Correlation analyses found statistically significant correlations between airborne mercury exposure and urine mercury level (P=0.01), and between urine mercury level and urine NAG excretion (P=0.01). In addition, the airborne mercury exposure data and urine mercury data were segregated by job tasks. A Wilcoxon rank sum test revealed significant correlations between tasks and mercury exposure (P=0.03), and between tasks and urine mercury level (P=0.02). Conclusions: The tasks with the highest mean airborne mercury exposures were “burning the mercury-gold amalgam” and “gold refining/smelting”. Recommendations were provided for improving the retort design to better contain mercury, for ventilation in the gold shops, and for medical surveillance and educational programs.     

Systematic review and quantification of respiratory cancer risk for occupational exposure to hexavalent chromium

Aim

To investigate the exposure-risk relationship for occupational chromium (VI) exposure and lung cancer in order to establish exposure limits.

Methods

We systematically searched for studies reporting on occupational Cr(VI) exposure and cancers of the respiratory tract. To be included, studies needed to provide data for more than one level of occupational Cr(VI) exposure, adequately consider the confounder smoking and be of adequate methodological quality. Because direct genotoxicity was considered the predominant mechanism of carcinogenesis of Cr(VI), linear models were applied in order to fit risk data. Relative risks were calculated based on these linear regression models and then used to estimate excess absolute risks.

Results

Five studies of two cohorts of chromium production workers in Baltimore, Maryland, and Painesville, Ohio, were included. Based on different estimates for the exposure effect, the absolute excess risk was found to be “acceptable” (less than 4 per 10,000 according to the German Committee on Hazardous Substances, “AGS”) at a Cr(VI) concentration of 0.1 μg/m³, and became “intolerable” (more than 4 per 1,000) beyond a Cr(VI) concentration of 1 μg/m³.

Conclusion

Occupational exposure limits for Cr(VI) based on excess absolute risks can be derived from published data identified by a systematic literature review.     

Smoking topography and biomarkers of exposure among Japanese smokers: associations with cigarette emissions obtained using machine smoking protocols

Objectives

Although the relative risk of lung cancer due to smoking is reported to be lower in Japan than in other countries, few studies have examined the characteristics of Japanese cigarettes or potential differences in smoking patterns among Japanese smokers.

Methods

To examine tar, nicotine and carbon monoxide (TNCO) emissions from ten leading cigarettes in Japan, machine smoking tests were conducted using the International Organization for Standardization (ISO) protocol and the Health Canada Intense (HCI) protocol. Smoking topography and tobacco-related biomarkers were collected from 101 Japanese smokers to examine measures of exposure.

Results

The findings indicate considerable variability in the smoking behavior of Japanese smokers. On average, puffing behaviors observed among smokers were more similar to the parameters of the HCI protocol, and brands with greater ventilation that yielded lower machine values using the ISO protocol were smoked more intensely than brands with lower levels of ventilation. The smokers of “ultra-low/low” nicotine-yield cigarettes smoked 2.7-fold more intensively than those of “medium/high” nicotine-yield cigarette smokers to achieve the same level of salivary cotinine (p = 0.024). CO levels in expiratory breath samples were associated with puff volume and self-reported smoking intensity, but not with nominal values of nicotine-yield reported on cigarette packages.

Conclusions

Japanese smokers engaged in “compensatory smoking” to achieve their desired nicotine intake, and levels of exposure were greater than those suggested by the nominal value of nicotine and tar yields reported on cigarette packages.     

Diets high in total antioxidant capacity improve risk biomarkers of cardiovascular disease: a 9-month observational study among overweight/obese postmenopausal women

Background

Previous studies have shown that total antioxidant capacity (TAC) of typical diets is associated with higher plasma TAC and antioxidant enzyme activities. At present, however, little is known for the association between dietary TAC and inflammatory biomarkers.

Aim

The present study was designed to examine the association between dietary TAC and inflammatory biomarkers in a group of overweight/obese postmenopausal women, a population with high cardiovascular disease (CVD) risk, during a 9-month period.

Methods

Thirty-five postmenopausal, overweight or obese, but apparently healthy women aged 40–70 years were recruited for a 9-month observational study. Seven-day food records and 12-h fasting blood samples were collected at baseline and at the end of the study for dietary and plasma biomarker assessments. Dietary TAC was calculated theoretically for taking account of both diet and dietary supplements, and energy-adjusted values were obtained using residual method.

Results

At baseline, subjects consuming diets with high dietary TAC had lower levels of plasma C-reactive protein (CRP) and monocyte chemoattractant protein-1 (p < 0.05) compared with those with low dietary TAC. Over the 9-month period, change in dietary TAC had a negative partial correlation with plasma CRP levels (p < 0.01) when age, ethnicity, and changes in BMI, blood total cholesterol and triglyceride were adjusted.

Conclusions

Findings suggest that consumption of diets high in TAC are inversely associated with plasma CRP levels cross-sectionally and dynamically and may contribute to CVD protection.     

Elimination kinetics of diisocyanates after specific inhalative challenges in humans: mass spectrometry analysis, as a basis for biomonitoring strategies

Objectives

to assess environmental and biological monitoring of exposure to organic solvents in a glue-manufacturing company in Sfax, Tunisia.

Methods

Exposure of volunteer workers, in the solvented glue-work-stations, in the control laboratory and in the storage rooms of the finished products, was assessed through indoor-air and urine measurements. Informed consent of the workers was obtained.

Results and discussion

The exposure indexes were found with high values in the solvented workshop as well as in the control laboratory and were respectively, 8.40 and 3.12. These indexes were also correlated with hexane and toluene indoor air concentrations. As to urine, the obtained results for the 2,5-hexandione and hippuric acid, metabolites of hexane and toluene, respectively, were in accord with the indoor-air measurements, with an average of 0.46 mg/l and 1240 mg/g of creatinine.

Conclusion

This study assessed for the first time biological exposure to organic solvents used in Tunisian adhesive industries. Although values are likely to underestimate true exposure levels, some figures exceed European and American occupational exposure guidelines.