Preshift Values Research Articles

To Study Acute Changes in Brain Oxygenation on MRI in Healthcare Workers Using N95 Mask and PPE Kits for Six Hours a Day.

Background Due to long working hours wearing an N95 mask and PPE kit during the COVID-19 pandemic, the healthcare workers (HCWs) complained of headaches, confusion, and exhaustion. This study was therefore performed to study the changes in brain oxygenation. Aim To compare brain oxygenation in health care workers wearing an N95 mask with a PPE kit versus a three-ply mask during an intensive care setting for 6 hours. Materials and Methods Thirty clinicians and 30 paramedical staff participated in the study. The control (three-ply mask) and subject (N95 mask with PPE) groups included 15 clinicians and 15 paramedical staff. A comparative analysis of brain oxygenation using a 3T magnetic resonance imaging (MRI) machine was performed in these two groups at the beginning and the end of their work shift. Results The mean age of the individuals in the control and subject groups was 30.8 and 30.13 years, respectively. The median value of brain oxygenation in the control and subject groups in the pre-shift was between 33 and 31 and post-shift was 30 and 24. The drop in brain oxygenation in subjects was more than the controls ( p = 0.004) in the post-shift assessments. The cerebral blood flow (CBF) in the bilateral middle cerebral artery (MCA) using arterial spin labeling (ASL) showed a rise in CBF in both groups post-shift as compared with the pre-shift values. The median values of the right and left MCA in the control and subject groups pre-shift were 82.75/83.45 and 89.75/106.65. The post-shift median values of both MCAs of the control and subject groups were 115.65/115.55 and 109.60/119.49. Conclusion MRI-BOLD imaging revealed a significant drop in brain oxygenation in the subject group as compared with the control group. Multiphasic-ASL showed a compensatory rise in CBF in both groups.

Molybdenum Occupational Study in a French Cohort of Workers.

Occupational exposure to molybdenum has been poorly documented to date. Here, we present a retrospective study evaluating urinary molybdenum concentration before and after shift over a period of 2 years in exposed workers. This retrospective study was conducted across eight industrial sites in France and included all workers undergoing medical follow-up for occupational molybdenum exposure. A mean of six sequential samples (before and after shift) was performed for each worker. The urinary molybdenum concentration was determined using a validated method of inductively coupled plasma-mass spectrometry. A mixed linear model was built and linear regression was used to verify the extent to which the urinary molybdenum concentration depends on the age of the workers and the sampling period. Additionally, an analysis based on individual trajectory was also performed. Seventy-seven workers were included in the present study. Post-shift urinary molybdenum concentrations were significantly higher than pre-shift values [median (95th percentile) 37.9 (91.1), versus 60.6 (190.0) µg g-1 creatinine, respectively, P < 0.009]. No accumulation of molybdenum over time was observed. The urinary molybdenum concentrations were not influenced by age. Four workers presented high post-shift values as a result of not adhering to protection measures (maxima of 529.8, 359.7, 386.3, and 1459.7 µg g-1 creatinine, respectively). To our knowledge, this is the first study of occupational molybdenum exposure in France to include an individual trajectory analysis. No accumulation of molybdenum was seen but high post-shift molybdenum urinary concentrations were observed for some workers. The study emphasizes the importance of molybdenum monitoring in exposed workers.

Urinary biomonitoring of occupational exposures to Bisphenol A Diglycidyl Ether (BADGE) - based epoxy resins among construction painters in metal structure coating.

Epoxy resin systems based on Bisphenol A Diglycidyl Ether (BADGE) monomer and its higher oligomers are important commercial formulations used widely in construction for protective coating of steel structures, such as bridges. The literature on occupational exposures and biomonitoring of BADGE-based epoxies among construction painters is remarkably limited. In this first occupational biomonitoring study of epoxies, 44 construction painters performing mid- and top-coating were recruited from 12 metal structure coating sites in New England. Cross-shift changes in the urinary levels of total BADGE and its three major hydrolysis derivatives - BADGE·2H2O, BADGE·H2O, BADGE·HCl·H2O - were assessed. Results for 81 urine samples collected from coating workers were compared with 28 urine samples of a reference group of 14 spray polyurethane foam (SPF) insulation workers. The highest concentrations of all biomarkers were found in the urine samples of mid-coat applicators. The major urinary biomarker of BADGE in this cohort of workers, BADGE·2H2O, was detected in 100% of urine samples. The post-shift BADGE·2H2O (specific gravity normalized data) in mid-coat applicators had a geometric mean (GM) of 1.46ng/mL and a geometric standard deviation (GSD) of 3.6 (range, 0.2-18.7ng/mL). The second most abundant biomarker in urine, BADGE·HCl·H2O, was measured in 84% of samples, and had a post-shift GM(GSD) of 0.17 (2.3) ng/mL (range, <0.025-0.59ng/mL). BADGE·2H2O was 8.6 times more abundant than BADGE·HCl·H2O. BADGE·H2O was quantified only in 10% of the samples (range, 0.11-0.41ng/mL). Free BADGE in post-shift urine, corrected for background, had GM (GSD) of 0.04 (2.5) ng/mL (range, <0.025-0.16ng/mL). Urinary BADGE·2H2O were significantly higher (p=0.01) in mid-coat applicators compared to top-coat and SPF workers. Post-shift urinary BADGE·2H2O in mid-coat applicators increased by ~2.9× (p=0.02) and 1.36× in top-coat applicators (p=0.18) compared to pre-shift values, but not in SPF workers (0.95×; p=0.40). In conclusion, we demonstrate that (i) significant BADGE uptake occurs via inhalation and skin exposures during application of epoxy-containing paintings (mid-coat), suggesting the need for improvements in hygiene practices and personal protective measures; (ii) BADGE·2H2O is a robust and sensitive biomarker for biomonitoring of exposures to BADGE-based epoxies in occupational settings; and (iii) widespread occurrence of BADGE and BADGE·2H2O in the urine of all workers, including SPF workers, suggest common exposures from non-occupational sources, such as ingestion or do-it-yourself consumer applications of epoxy resins. In light of this observation, establishing a reliable biological monitoring guidance value (BMGV) for BADGE·2H2O will require more background biomonitoring and health effect data. An initial reference value for BADGE·2H2O of 0.5ng/mL (SG-normalized) or 180nmol/mol creatinine is being proposed as the threshold to discriminate occupational from non-occupational exposures based on the maximum values observed in the reference SPF group.

Biological monitoring of urinary lead: Preshift and postshift sampling detects efficiently recent lead exposure and signals the need to review and possibly improve controls at work

The objective of this study is to highlight the effectiveness of urinary lead as an index of recent lead exposure. In the past scientific literature urinary lead has been studied as a parameter for recent lead exposure. It is a reliable indicator for occupational lead exposure. But, strangely enough, nowadays is scarcely used in the Netherlands and worldwide. We performed six field biological monitoring studies of preshift and postshift urinary lead tests during tank maintenance and bridge repair work. Highest values occurred during bridge repair. Mean urinary values were postshift 1,6−5 times higher than preshift values, indicating clearly recent lead exposure and failing protective measures. This is so far we know the first study combining preshift and postshift sampling of urinary lead. We compared our studies with crossectional and follow-up studies in occupational medicine. Our conclusion is that preshift and postshift urinary lead testing is a worker friendly test, ideally for detecting recent lead exposures in the field. It signals the need to review or possibly improve controls at work.There are no safe lead levels, so we recommend to use a target value for urinary lead of <3 μg/g creatinine for all lead workers in the Netherlands.

Evaluation of heat stress and cumulative incidence of acute kidney injury in sugarcane workers in Guatemala

ObjectiveAgricultural workers worldwide exposed to heat stress could be at the risk of kidney injury, which could lead to chronic kidney disease of an unknown origin (CKDu). Hydration has been promoted as a key measure to reduce kidney injury. In the presence of a hydration intervention, the incidence of acute kidney injury (AKI) was calculated in a sugarcane worker population in Guatemala and several risk factors were evaluated.MethodsWe measured kidney function at the beginning and end of the work shift at three time points in 517 sugarcane workers. We defined AKI as an increase in serum creatinine of 26.5 µmol/L or 50% or more from the pre-shift value. Associations between AKI and risk factors were examined, including interactions with hydration status.ResultsThe prevalence of dehydration post-shift (> 1.020 specific gravity) was 11% in February, 9% in March, and 6% in April. Cumulative incidence of AKI was 53% in February, 54% in March, and 51% in April. AKI was associated with increasing post-shift specific gravity, a dehydration marker, (OR 1.24, 95% CI 1.02–1.52) and with lower electrolyte solution intake (OR 0.94, 95% CI 0.89–0.99).ConclusionsDehydration and insufficient electrolyte consumption are risk factors for AKI. However even well-hydrated sugarcane workers routinely experience AKI. While hydration is important and protective, there is a need to understand other contributors to risk of AKI and identify prevention strategies with these workers.

Intrusion of chlorinated hydrocarbons and their degradation products from contaminated soil. Measurement of indoor air quality and biomonitoring by analysis of end-exhaled air

A historic soil contamination of chlorinated hydrocarbons from a former dry cleaning shop caused intrusion of vapors into a building currently used as bookshop. The aim of this study was to determine the indoor air quality and the uptake of soil contaminants and their degradation products. Samples of indoor air were collected over one week in the warm and one week in the cold season. Pre-shift and post-shift samples of end-exhaled air were collected from two employees. Chlorinated hydrocarbons were analyzed in indoor air and exhaled air samples using thermal desorption gas chromatography mass spectrometry (TD-GC–MS). Tetrachloroethylene (PER), and its degradation products trichloroethylene (TRI), 1,1-dichloroethylene (1,1-DCE), 1,2-cis-dichloroethylene (1,2-cis-DCE), 1,2-trans-dichloroethylene (1,2-trans-DCE), methylene chloride (MC) and vinyl chloride (VC) were determined in ambient air. PER was the prime contaminant with a week average (±sd) of 805.2 ± 598.6 μg/m3 in June 2016 and 1031 ± 499.3 μg/m3 in December 2017. MC, 1,2-cis-DCE and TRI were detected at concentrations below 2.3 μg/m3. 1,1-DCE and VC were not detected. In exhaled air PER, 1,1-DCE, and MC were detected in both June and December, whereas TRI, 1,2-cis-DCE and 1,2-trans-DCE were only detected on one or two days in the cold season. VC was not detected in exhaled air. For PER, the mean concentrations (±sd) in end-exhaled air increased from a five days (Mon-Fri) average pre-shift value of 22.2 ± 8.0 to a post-shift value of 52.6 ± 15.5 ng/L in the male shop owner (p < 0.01) and in the female cashier these values were 26.0 ± 3.6 and 63.6 ± 12.7 ng/L, respectively (p < 0.01). Intrusion of chlorinated soil contaminants resulted in contamination of indoor air above the current accepted indoor air level for PER of 250 μg/m3. For PER in end-exhaled air an accumulation over the workweek was not observed.

Exposure to Cooking Fumes and Acute Reversible Decrement in Lung Functional Capacity.

Background: Being exposed to cooking fumes, kitchen workers are occupationally at risk of multiple respiratory hazards. No conclusive evidence exists as to whether occupational exposure to these fumes is associated with acute and chronic pulmonary effects and symptoms of respiratory diseases. Objective: To quantify the exposure levels and evaluate possible chronic and acute pulmonary effects associated with exposure to cooking fumes. Methods: In this cross-sectional study, 60 kitchen workers exposed to cooking fumes and 60 unexposed employees were investigated. The prevalence of respiratory symptoms among these groups was determined through completion of a standard questionnaire. Pulmonary function parameters were also measured before and after participants' work shift. Moreover, air samples were collected and analyzed to quantify their aldehyde, particle, and volatile organic contents. Results: The mean airborne concentrations of formaldehyde, acetaldehyde, and acrolein was 0.45 (SD 0.41), 0.13 (0.1), and 1.56 (0.41) mg/m3, respectively. The mean atmospheric concentrations of PM1, PM2.5, PM7, PM10, and total volatile organic compounds (TVOCs) was 3.31 (2.6), 12.21 (5.9), 44.16 (16.6), 57 (21.55) µg/m3, and 1.31 (1.11) mg/m3, respectively. All respiratory symptoms were significantly (p<0.05) more prevalent in exposed group. No significant difference was noted between the pre-shift mean of spirometry parameters of exposed and unexposed group. However, exposed workers showed cross-shift decrease in most spirometry parameters, significantly lower than the pre-shift values and those of the comparison group. Conclusion: Exposure to cooking fumes is associated with a significant increase in the prevalence of respiratory symptoms as well as acute reversible decrease in lung functional capacity.

Thermal Stress in North Western Australian Iron Ore Mining Staff

Demand for Australian mined iron ore has increased employment within this sector, thus exposing increased numbers of workers to the harsh Australian climate. This study examined the influence of hot (>30°C wet bulb globe temperature) environmental temperatures, consistent with working in North Western Australia, on iron ore mining staff. Core temperature, hydration status, perceived exertion, mood, and fatigue state were measured in 77 participants at three time points (pre-, mid-, and post-shift) during a normal 12-h shift at an open-cut iron ore mining/processing site (n = 31; Site1) and an iron ore processing/shipping site (n = 46; Site2). A significant effect for time was observed for core temperature with greater mean core temperatures measured mid-shift (37.5±0.4°C) and post-shift (37.6±0.3°C) compared with pre-shift values (37.0±0.5°C). All mean core temperature measures were lower than ISO7933 thresholds (38°C) for thermal safety. Mean hydration measures [urine-specific gravity (USG)] were greater at Site1 (1.029±0.006) compared with those at Site2 (1.021±0.007). Furthermore, both pre- and post-shift measures from Site1 and the post-shift measures from Site2 were greater than the threshold for dehydration (USG = 1.020). No differences were observed for mood or perceived exertion over time; however, measures of fatigue state were greater post-shift compared with pre- and mid-shift values for both sites. Our findings indicate that the majority of mine workers in North Western Australia are able to regulate work rate in hot environments to maintain core temperatures below ISO safety guidelines; however, 22% of workers reached or exceeded the safety guidelines, warranting further investigation. Furthermore, hydration practices, especially when off-work, appear inadequate and could endanger health and safety.

Modulation of Oxidative DNA Damage by Repair Enzymes XRCC1 and hOGG1

The influence of DNA repair gene polymorphisms (XRCC1: Arg194Trp, Arg280His, Arg399Gln; APE1: Asp148Glu; hOGG1: Ser326Cys) on oxidative DNA damage is controversial and was investigated in 214 German workers with occupational exposure to vapors and aerosols of bitumen,compared to 87 German construction workers without exposure, who were part of the Human Bitumen Study. Genotypes were determined by real-time polymerase chain reaction (PCR), and actual smoking habits by a questionnaire and cotinine analysis. Oxidative DNA damage in white blood cells (WBC) collected pre- and postshift was measured as 8-oxodGuo adducts/106 dGuo by a hjigh-performance liquid chromatography electron capture detection (HPLC-ECD) method, followed by calculation of the difference between post- and preshift values (Δ8-oxodGuo/106 dGuo). The 214 bitumen exposed workers showed higher median Δ8-oxodGuo values than the 87 references. In the whole study group (n = 301) there was a trend for increasing adduct values for XRCC1 Arg(GG)399Gln(AA) during a shift, especially in nonsmokers (n = 108. Referents (n = 87) displayed a similar trend for hOGG1 Ser(CC)326Cys(GG). In contrast, XRCC1 Arg(GG)280His(AA) showed a decrease of median Δ8-oxodGuo/106 dGuo values in workers with exposure to vapors and aerosols of bitumen (n = 214), especially in smokers (n = 145). XRCC1 Arg194Trp and APE1 Asp148Glu displayed no marked association with Δ8-oxodGuo levels. Data indicate that the combination of different variants in DNA damage repair enzymes may modulate the production of 8-oxoguanine adducts in WBC produced by xenobiotics during a shift.

Phthalate exposure during cold plastisol application—a human biomonitoring study

The phthalates DEHP (Diethylhexyl phthalate), DiNP (Diisononyl phthalate) and DiDP (Diisodecyl phthalate) are constituents of plastisols. We sought to obtain first data on occupational exposures to the above phthalates by analyzing their metabolites in pre- and post-shift urine samples from 5 workers in a car manufacturing plant engaged in seam sealing with a DINP based plastisol. Pre-shift samples were collected after a work-free period of at least 2 days. As a comparison group we investigated 10 employees from the same plant.The comparison group had phthalate exposures in the range of the general German population. All plastisol workers had post shift values of DiNP and DiDP metabolites that were approx. 20-times higher, and pre-shift values that were approx. 5–10 times higher than those of the general background exposure. Post-shift values of DiNP metabolites were (median [maximum]: OH-MiNP: 117 [442]μg/L; oxo-MiNP: 44.3 [175]μg/L; carboxy-MiNP: 57.8 [286]μg/L), pre shift values were (OH-MiNP: 26 [164]μg/L; oxo-MiNP 12.9 [68.6]μg/L; carboxy-MiNP: 32.3 [103]μg/L), compared to the comparison group (OH-MiNP: 6.2 [33]μg/L; oxo-MiNP: 2.8 [16]μg/L; carboxy-MiNP: 6.5 [31]μg/L). DiDP values were generally lower. Regarding DEHP we found no significant work related exposure. The dermal exposure route might play an important role for phthalates in plastisols, with possible influences on distribution and elimination kinetics and therefore data interpretation.

Respiratory Morbidity Induced by Occupational Inhalation Exposure to Formaldehyde

The potential of formaldehyde to produce chronic respiratory tract disease remains a controversial issue. The main purpose of this study was to investigate the respiratory effects, if any, of long term occupational exposure to formaldehyde. This cross-sectional study was carried out at a local melamine-formaldehyde resin producing plant. The study population consisted of seventy exposed and 24 non-exposed (referent) employees. Using respiratory questionnaire, data on respiratory symptoms were gathered. Atmospheric concentrations of formaldehyde were measured at different contaminated areas of the plant. Similarly, the parameters of pulmonary function were measured at the beginning (preshift) and at the end (postshift) of the first working day of the week. The results showed that airborne concentrations of formaldehyde exceeded current permissible levels. Additionally, significant decrements in some preshift and postshift parameters of pulmonary function of exposed workers were noted. However, a relative recovery in lung functional capacity observed following temporary cessation of exposure (preshift values). Furthermore, exposed workers had higher prevalence rates of regular cough, wheezing, phlegm, shortness of breath, chest tightness and episodes of chest illness associated with cold. The findings of this study collectively indicate that exposure to formaldehyde may induce respiratory symptoms, acute partially reversible and chronic irreversible functional impairments of the lungs.

Ergonomics

Changes in heart rate variability (HRV) have been linked with cardiac disease and death. Exposure to particulate matter from various sources such as tobacco smoke has been shown to cause alterations in HRV. This study investigated the effects of occupational exposure to environmental tobacco smoke (ETS) on HRV. Air monitoring was conducted in three bars in which smoking was permitted and one bar where smoking was not permitted. Pre- and post-work shift heart rate monitoring was conducted on volunteer staff from the establishments. Heart rate variability parameters, including SDNN and RMSSD, were calculated, and the differences between pre- and post-shift values were plotted and analyzed with respect to ETS exposure. Post-shift minus pre-shift values of SDNN and RMSSD significantly decreased with exposure to ETS (p < 0.05). Occupational exposure to ETS may decrease heart rate variability.

Orbital tuning as an inverse problem: Chronology of the early Aptian oceanic anoxic event 1a (Selli Level) in the Cismon APTICORE

[1] Orbital tuning, the process of fitting sedimentary cycles to orbital periodicities, can estimate with high resolution the timing and duration of key events in the geological record. We formulate here orbital tuning as the inverse problem of finding the variation in sedimentation rate that matches sediment cycles with orbital periodicities. Instead of obtaining a single best estimate, we apply a Bayesian formulation and define a probability distribution of sedimentation rate variations that result in powerful orbital periodicities. By sampling this distribution with a Monte Carlo method, we quantify the uncertainty in the inferred sedimentation rates due to uncertainties in the tuning periods and to components of the sedimentary signal that are unrelated to orbital cycles. The method is applied to the chronology of a 30 m interval in the Cismon APTICORE borehole (Southern Alps, Italy) that includes the early Aptian oceanic anoxic event 1a (Selli Level), estimated to last 1.11 ± 0.11 Ma (95% interval). The δ13C record shows a sudden negative shift of about −1‰ at the base of the Selli Level (22–47 ka) followed by a recovery to preshift values in ∼240 ka, consistent with a scenario where light carbon is quickly added and then flushed out of the ocean-atmosphere system.

Biological monitoring of tungsten (and cobalt) in workers of a hard metal alloy industry

To evaluate a combined biomonitoring approach based on both cobalt and tungsten determination in workers of the hard metal alloy sector. We enrolled 55 workers from a factory producing cutting tools for carpentry. Combined workroom air and biological monitoring of both cobalt and tungsten relied on inductively coupled plasma mass spectrometry determinations. Metals were determined on plasma, blood and urine samples. Urine samples from 34 unexposed subjects were also analyzed. Tungsten was determined in every collected sample. Workers showed significantly higher urinary tungsten levels than controls (pre-shift values of 4.12 vs. 0.06 microg/l on average; P < 0.0005). Both airborne and biological levels of tungsten prevailed among workers involved in wet-grinding activities. The element was excreted at higher urinary levels than cobalt and showed lower circulating (blood, plasma) concentrations. Exposure-dose relationships were apparent for tungsten biomarkers. Obtained results may contribute to the development of biomarkers of exposure to tungsten. The association of such biomarkers to traditional determinations of cobalt in blood and/or urine may substantially improve the exposure assessment of workers employed in cemented carbide industries.

Correlation between urinary methoxyacetic acid and exposure of ethylene glycol dimethyl ether in a lithium battery plant

To examine the correlation between airborne ethylene glycol dimethyl ether (EGdiME) exposures and the urinary methoxyacetic acid (MAA) and to approach the issue of a permissible exposure limit for EGdiME. The survey was conducted on Thursday. Workers occupationally exposed to EGdiME, as well as nonexposed controls, were studied in combination with one of the authors, who was coincidentally exposed to EGdiME while carrying out the study. Air levels of EGdiME were determined by personal sampling on passive gas tubes. Urine was collected from nine control subjects and ten workers immediately before and after the shift, and from one of the authors at intervals during 12 h. The analyses of EGdiME in air and MAA in urine were performed by gas chromatography with flame ionization detection. The time-weighted average (TWA) air levels of EGdiME ranged from 0.7 to 10.5 ppm during 8 h work shifts. The urinary levels of MAA in one of the authors increased continuously during exposure and after the end of exposure. The levels of urinary MAA in the exposed workers were significantly higher than those in the control subjects. On the other hand, the postshift values were higher than the preshift values in the exposed workers, but the difference was not significant. A linear correlation was found between the TWA air levels of EGdiME and creatinine-adjusted MAA levels in urine collected at the end of the shift (r = 0.933; P < 0.0001). According to our equation, a linear extrapolation to the biological limit value recommended by Shih et al. (1999) of 40 mg MAA/g crea indicated an average inhalation exposure to EGdiME over the workweek of 12 ppm. These results indicate that the determination of MAA in urine is suitable for use in the biological monitoring of EGdiME exposure.

Environmental and biological monitoring of benzene exposure in a cohort of Italian taxi drivers

An integrated approach based on ambient and biological monitoring, the latter including both biomarkers of exposure and susceptibility, was applied to characterize benzene exposure in a group of 37 taxi drivers of the city of Parma (Italy). Airborne benzene concentrations were assessed by 24 h personal sampling and work-shift sampling inside the taxicab using passive samplers (Radiello ®). Benzene metabolites, trans, trans-muconic acid ( t, t-MA) and S-phenylmercapturic acid ( S-PMA), and urinary cotinine as biomarker of smoking habits were measured by isotopic dilution liquid chromatography tandem mass spectrometry in both pre-shift (PS) and end-of-shift (EOS) samples. Urinary benzene (U-B) levels were determined by solid-phase microextraction gas chromatography–mass spectrometry in EOS samples. Relevant polymorphisms of microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, glutathione S-transferases M1-1 ( GSTM1), T1-1, and A1 were characterized by PCR-based methods. Mean airborne benzene concentration was 5.85 ± 1.65 μg/m 3, as assessed by 24 h personal sampling integrating for work-shift, indoor or general environment activities. Significantly, higher benzene concentrations were detected in the taxicab during the work-shift (7.71 ± 1.95 μg/m 3, p < 0.005). Smokers eliminated significantly higher concentrations of U-B and S-PMA than non-smokers in EOS samples [geometric mean (geometric S.D.): 2.58 (4.23) versus 0.44 (1.79) μg/l for U-B; 3.79 (1.50) versus 2.14 (1.87) μg/g creat. for S-PMA, p < 0.002]. Within smokers, S-PMA concentrations significantly increased at the end of the work-shift compared to pre-shift values ( p < 0.05). t, t-MA showed a similar behaviour, although differences were not significant. In the narrow range examined, no correlation was observed between air benzene concentration and urinary biomarkers. All benzene biomarkers but EOS t, t-MA were correlated with U-cotinine ( p < 0.05). GSTM1 polymorphism significantly modulated S-PMA excretion, as subjects bearing the GSTM1pos genotype [3.61 (1.15) μg/g creat.] excreted significantly higher S-PMA concentrations than GSTM1null subjects [2.19 (1.18) μg/g creat., p < 0.05].

3-Hydroxybenzo[a]pyrene in the urine of smokers and non-smokers

The people studied were male volunteers without occupational and dietary exposure to PAH: 27 smokers (10 cigarettes or more) and 27 non-smokers matched for age and socio-professional category. For each person, all the 24 h voided urine samples were reassembled in a single sample. 1-Hydroxypyrene (1-OHPy) and 3-hydroxybenzo[a]pyrene (3-OHBaP) were then determined by automated column-switching high-performance liquid chromatography. Urinary 1-OHPy ranged from 0.041 to 0.530 μmol/molCreatinine (arithmetic mean 0.144, median 0.115) for smokers and from 0.01 to 0.148 μmol/molCreatinine (arithmetic mean 0.044, median 0.032) for non-smokers. These values are close to those of some other studies. Urinary 3-OHBaP ranged from <0.01 to 0.084 nmol/molCreatinine (arithmetic mean 0.030, median 0.023) for smokers and from <0.01 to 0.045 nmol/molCreatinine (arithmetic mean 0.014, median 0.011) for non-smokers. Considering more particularly the urinary 3-OHBaP values, the influence of smoking could be important among workers exposed to low levels of BaP (<100 ng/m 3) and the concentrations for smokers were equivalent to most of the preshift values of exposed workers. The dietary BaP intake was slightly lower than the BaP intake for an average smoker. From the present study, temporary basic reference levels may be proposed for urinary 3-OHBaP.

Effects of Carbohydrate Supplementation on Salivary Immunoglobulin- A During Long Duration Arduous Work

2191 Prior short-term exercise studies have shown no effect of carbohydrate (CHO) supplementation on post-exercise suppression of salivary Immunoglobulin-A (sIgA). PURPOSE: This study evaluated the effects of CHO supplementation in wildland. re. ghters (WLFF) over an extended work shift on post-exercise and 12 hr recovery sIgA values. METHODS: Subjects were 29 WLFF evaluated during an extended shift of firefighting. In a single blind, random crossover design, WLFF on subsequent days received either a CHO [200ml/hr, 20% maltodextrin (160 kcal/hr)] or placebo (PLA) drink each hour. At the completion of the shift the CHO group received an additional bolus of 400 kcal CHO. Four minute forced salivary samples were collected pre- and post-shift and the morning after each treatment. Samples were analyzed using an Elisa assay. A two-way repeated measures ANOVA was used to evaluate the salivary data. RESULTS: Immediately post-shift both groups had a significant decrease in sIgA content over pre-shift values while the CHO group had significantly less sIgA suppression compared to the PLA group (pre-shift: CHO = 429 ± 139, PLA = 437 ± 159; post-shift: CHO = 290 ± 160, PLA = 230 ± 111, p<0.05). Following 12 hours of rest the CHO groups had returned to pre-shift values, while the PLA group remained significantly immune depressed (CHO = 442 ± 171, PLA = 337 ± 136, p<0.05). Additionally, during the final 6 hours of the CHO trial the subjects performed 23% more work (CHO = 486 ± 36, PLA = 395 ± 28 kcal/hr, p<0.01) and maintained higher blood glucose values compared to PLA, but there were no differences in RPE across trials. CONCLUSION: Exercise has been shown to cause a decrease in sIgA and is associated with increased incidence of upper respiratory tract infection. CHO supplementation during long shifts of arduous work in WLFF enhances maintenance of immune function and improved recovery after extended arduous work in spite of the greater self-selected work with CHO. The mechanism for the improved immune function is unknown but may be related to increased cortisol concentrations associated with longer duration exercise. Supported by the U.S. Forest Service, Missoula Technology Development Center.

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

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. 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. 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, FEV(1), 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). 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.

N,N-dimethylformamide--influence of working conditions and skin penetration on the internal exposure of workers in synthetic textile production.

This study examined the external and internal exposure to the solvent N,N-dimethylformamide (DMF) of 126 workers from a factory producing synthetic fibers. Air measurements were carried out using personal air samplers with diffusion tubes (Drager, ORSA 5). For the purpose of biological monitoring the levels of N-methylformamide (NMF) in urine were measured in preshift and postshift samples. Determinations were carried out using gas chromatography. Anamnestic data were collected with standardized questionnaires, including personal data, working history and current working conditions, and former and current illness with regard to the effects of DMF. Skin diseases were documented by a dermatologist. DMF concentrations measured in the air ranged between <0.1 and 37.9 ppm (median 1.2 ppm). Concentrations of NMF varied from 0.05 to 22.0 mg/l (preshift values) and from 0.9 to 100.0 mg/l (postshift values). The creatinine-related values (0.02-44.6 mg/g preshift; 0.4-62.3 postshift) were subject to less variation and therefore represented the level of exposure better than the values related to volume. Additional investigation of a subcollective (n=31) over a period of 4 days showed that NMF did not accumulate in the organism. The positive but relatively weak association observed between the DMF concentrations measured in the workplace air and the values recorded for internal exposure in this study can be explained by influencing factors such as dermal absorption or protective clothing. Interindividual differences in internal exposure were found for the specific work areas. The German BAT value (15 mg NMF/l urine) was exceeded in 36 persons (29%) despite the use of breathing protection and protective gloves, without increased values being measured in the air. Increased absorption without higher-level exposure could particularly also be observed in employees with eczema. From the point of view of the prevention of disease, biological monitoring is the best instrument for exposure assessment of workers exposed to DMF.