Determining Which Combinatorial Combat-Relevant Factors Contribute to Heterotopic Ossification Formation in an Ovine Model.

Traumatic heterotopic ossification (HO) is frequently observed in Service Members following combat-related trauma. Estimates suggest that ~65% of wounded warriors who suffer limb loss or major extremity trauma will experience some type of HO formation. The development of HO delays rehabilitation and can prevent the use of a prosthetic. To date there are limited data to suggest a standard mechanism for preventing HO. This may be due to inadequate animal models not producing a similar bone structure as human HO. We recently showed that traumatic HO growth is possible in an ovine model. Within that study, we demonstrated that 65% of sheep developed a human-relevant hybrid traumatic HO bone structure after being exposed to a combination of seven combat-relevant factors. Although HO formed, we did not determine which traumatic factor contributed most. Therefore, in this study, we performed individual and various combinations of surgical/traumatic factors to determine their individual contribution to HO growth. Outcomes showed that the presence of mature biofilm stimulated a large region of bone growth, while bone trauma resulted in a localized bone response as indicated by jagged bone at the linea aspera. However, it was not until the combinatory factors were included that an HO structure similar to that of humans formed more readily in 60% of the sheep. In conclusion, data suggested that traumatic HO growth can develop following various traumatic factors, but a combination of known instigators yields higher frequency size and consistency of ectopic bone.

Occupational exposures of firefighting and urinary tract cancer risk among men in the Norwegian Fire Departments Cohort.

OBJECTIVES: Increased risks of bladder cancer and mesothelioma were the strongest evidence for the recent reclassification of firefighting as carcinogenic (Group 1) by the International Agency for Research on Cancer. Our study aim was to develop indicators for specific firefighting exposures and examine associations with urinary tract cancer (UTC), including bladder cancer. METHODS: We developed indicators for exposure from employment at a fire department or in firefighting jobs, to fire and smoke, and to diesel exhaust for men in the Norwegian Fire Departments Cohort (n=4250). Incident UTC cases were obtained from the Cancer Registry of Norway (1960-2021). Poisson regression was used to estimate incidence rate ratios (IRR) with cumulative exposures grouped into tertiles (reference: lowest exposed tertile) with 0-year, 10-year and 15-year lagging of exposures. RESULTS: During 125 090 person-years of follow-up, there were 76 cases of UTC. IRRs were mostly non-significantly increased in the middle tertile and at or below 1 in the highest tertile for total duration of employment, number of fires attended and fire exposure score with and without lags. In the middle tertile for diesel exhaust exposure, UTC risk was elevated over twofold with 10-year (IRR 2.27, 95% CI 1.22 to 4.20) and 15- year (2.21, 1.18 to 4.16) lags, and near 1 in the highest tertile. Findings for bladder cancer were similar to those for UTC. CONCLUSIONS: Dose-response associations between the exposure indicators and UTC were not observed. Future studies using the indicators with more cases are needed.

Chloroform exposure in air and water in Swedish indoor swimming pools-urine as a biomarker of occupational exposure.

INTRODUCTION: Disinfection by-products are produced in water disinfected with chlorine-based products. One such group is trihalomethanes, and chloroform is the most abundant trihalomethane in swimming pool areas. Chloroform can be absorbed by inhalation, ingestion, and dermal absorption, and is classified as possibly carcinogenic. AIM: To investigate if chloroform concentrations in air and water affect the chloroform concentration in urine samples of exposed swimming pool workers. METHODS: Workers from 5 adventure indoor swimming pools carried personal chloroform air samplers and provided up to 4 urine samples during one workday. Chloroform concentrations were analyzed with a linear mixed model analysis to investigate a possible correlation between air and urine concentrations. RESULTS: The geometric mean chloroform concentration was 11 µg/m3 in air and 0.009 µg/g creatinine in urine among individuals with ≤2 h at work, 0.023 µg/g creatinine among those with >2-5 working hours, and 0.026 µg/g creatinine in the group with >5-10 working hours. A risk of higher levels of chloroform in urine was associated with longer hours at work (≤2 h versus >5-10 h, odds ratio [OR] 2.04, 95% confidence interval [CI] 1.25-3.34), personal chloroform concentrations in air (≤17.00 µg/m3 versus >28.00 µg/m3, OR 9.23, 95% CI 3.68-23.13) and working at least half the working day near the swimming pools (OR 3.16, 95% CI 1.33-7.55). Executing work tasks in the swimming pool water was not associated with higher chloroform concentrations in urine compared to only working on land (OR 0.82, 95% CI 0.27-2.45). CONCLUSION: There is an accumulation of chloroform concentrations in urine during a workday and a correlation between personal air and urine concentrations of chloroform among workers in Swedish indoor swimming pools.

Developing a combat-relevant translatable large animal model of heterotopic ossification.

Heterotopic ossification (HO) refers to ectopic bone formation, typically in residual limbs following trauma and injury. A review of injuries from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) indicated that approximately 70% of war wounds involved the musculoskeletal system, largely in part from the use of improvised explosive devices (IED) and rocket-propelled grenades (RPG). HO is reported to occur in approximately 63%-65% of wounded warriors from OIF and OEF. Symptomatic HO may delay rehabilitation regimens since it often requires modifications to prosthetic limb componentry and socket size. There is limited evidence indicating a mechanism for preventing HO. This may be due to inadequate models, which do not produce HO bone structure that is morphologically similar to HO samples obtained from wounded warfighters injured in theatre. We hypothesized that using a high-power blast of air (shockwave) and simulated battlefield trauma (i.e. bone damage, tourniquet, bacteria, negative pressure wound therapy) in a large animal model, HO would form and have similar morphology to ectopic bone observed in clinical samples. Initial radiographic and micro-computed tomography (CT) data demonstrated ectopic bone growth in sheep 24 weeks post-procedure. Advanced histological and backscatter electron (BSE) analyses showed that 5 out of 8 (63%) sheep produced HO with similar morphology to clinical samples. We conclude that not all ectopic bone observed by radiograph or micro-CT in animal models is HO. Advanced histological and BSE analyses may improve confirmation of HO presence and morphology, which we demonstrated can be produced in a large animal model.

Occupational Exposure during Asphalt Paving-Comparison of Hot and Warm Mix Asphalt in Field Experiments.

OBJECTIVES: Several studies have demonstrated an increased risk of adverse health effects, including reduced lung function and lung cancer among asphalt pavers, which has been related to occupational exposure to contaminants during asphalt paving. Consequently, occupational exposure among asphalt pavers must be reduced. The aim of this study was to compare the impact of hot mix asphalt (HMA) and warm mix asphalt (WMA) paving on occupational exposure levels during road paving in field experiments. Asphalt temperatures when paving with WMA are usually lower than when paving with HMA due to differences in the asphalt's composition and method of application. METHODS: On 11 different road sections, one lane was paved with WMA and one with HMA during the same work shift under approximately identical weather conditions. The weather conditions and asphalt surface temperature were monitored during paving. Fifty-seven samples of fumes and vapor, organic and elemental carbon, amines, and respirable, thoracic, and inhalable particulate matter (PM) fractions were collected by stationary sampling. In addition, 30 samples of fumes and vapor were collected by personal sampling. RESULTS: Compared to paving with HMA, paving with WMA significantly (P < 0.05; paired Student's t-test) reduced the geometric mean (GM) air concentration of asphalt vapor (0.04 versus 0.08 p.p.m.), organic carbon (OC; 0.09 versus 0.18 mg m-3), and respirable PM (0.12 versus 0.22 mg m-3). Additionally, the air concentration of OC correlated strongly with the respirable fraction of PM (Pearson's correlation coefficient 0.83). CONCLUSIONS: Measured airborne concentrations of respirable PM, OC, and asphalt vapor were lower when paving with WMA than with HMA. Because exposure to airborne contaminants generated during asphalt paving is believed to be responsible for the adverse health effects observed among asphalt pavers, paving with WMA rather than HMA may have health benefits.

Work Conditions and Practices in Norwegian Fire Departments From 1950 Until Today: A Survey on Factors Potentially Influencing Carcinogen Exposure.

BACKGROUND: Meta-analyses have shown firefighters to be at an increased risk of several cancer types. Occupational carcinogen exposure may explain these increased risks. This study aims to describe Norwegian fire departments' work conditions from 1950 until today, focusing on factors relevant for potential occupational carcinogen exposure. METHODS: With the help of a reference group, we developed a questionnaire on topics related to occupational exposure to carcinogens for the period 1950-2018. Selected Norwegian fire departments provided department-specific responses. RESULTS: Sixteen departments, providing fire services for 48% of the Norwegian population as of 2019 and mainly consisting of professional firefighters, responded to our questionnaire. The introduction of synthetic firefighting foams, more regular live fire training, the introduction of chemical diving, and a higher number of diesel-driven fire service vehicles were identified as changes thought to increase exposure to occupational carcinogens. Changes thought to decrease exposure included the switch from negative to positive pressure self-contained breathing apparatuses, the use of self-contained breathing apparatuses during all phases of firefighting, the use of ventilating fans during firefighting, increased attention to flammable materials used during live fire training, increased attention to handling and cleaning of turnout gear and other equipment, and installment of exhaust removal systems in apparatus bays. CONCLUSION: Norwegian fire departments' work conditions have seen several changes since 1950, and this could influence firefighters' occupational carcinogen exposure. A peak of carcinogen exposure may have occurred in the 1970s and 1980s before recent changes have reduced exposure.

Biomonitoring of the benzene metabolite s-phenylmercapturic acid and the toluene metabolite s-benzylmercapturic acid in urine from firefighters.

The aim of this study was to determine firefighter's exposure to benzene and toluene during a fire drill by monitoring air benzene and toluene, and their corresponding urinary metabolites. A liquid chromatography mass spectrometry (LC-MS) method with a minimal of sample preparation steps was developed for the benzene metabolite s-phenylmercapturic acid (SPMA) and the toluene metabolite s-benzylmercapturic acid (SBMA) in urine. Urine samples and air samples were collected from nine firefighters during and after a fire drill in a non-environmentally refurbished house. Benzene and toluene were detected in the air samples with a median concentration of 15.5 ppm and 3.2 ppm, respectively. The metabolites SPMA and SBMA was also detected in all urine samples donated ≥ three hours after the fire drill with a median concentration of 0.6 µg/g creatinine and 5.9 µg/g creatinine, respectively. By our knowledge, this is the first study detecting SPMA in urine from firefighters.

Exposure Determinants of Wood Dust, Microbial Components, Resin Acids and Terpenes in the Saw- and Planer Mill Industry.

OBJECTIVES: Sawmill workers have an increased risk of adverse respiratory outcomes, but knowledge about exposure-response relationships is incomplete. The objective of this study was to assess exposure determinants of dust, microbial components, resin acids, and terpenes in sawmills processing pine and spruce, to guide the development of department and task-based exposure prediction models. METHODS: 2474 full-shift repeated personal airborne measurements of dust, resin acids, fungal spores and fragments, endotoxins, mono-, and sesquiterpenes were conducted in 10 departments of 11 saw- and planer mills in Norway in 2013-2016. Department and task-based exposure determinants were identified and geometric mean ratios (GMRs) estimated using mixed model regression. The effects of season and wood type were also studied. RESULTS: The exposure ratio of individual components was similar in many of the departments. Nonetheless, the highest microbial and monoterpene exposure (expressed per hour) were estimated in the green part of the sawmills: endotoxins [GMR (95% confidence interval) 1.2 (1.0-1.3)], fungal spores [1.1 (1.0-1.2)], and monoterpenes [1.3 (1.1-1.4)]. The highest resin acid GMR was estimated in the dry part of the sawmills [1.4 (1.2-1.5)]. Season and wood type had a large effect on the estimated exposure. In particular, summer and spruce were strong determinants of increased exposure to endotoxin (GMRs [4.6 (3.5-6.2)] and [2.0 (1.4-3.0)], respectively) and fungal spores (GMRs [2.2 (1.7-2.8)] and [1.5 (1.0-2.1)], respectively). Pine was a strong determinant for increased exposure to both resin acid and monoterpenes. Work as a boilerman was associated with moderate to relatively high exposure to all components [1.0-1.4 (0.8-2.0)], although the estimates were based on 13-15 samples only. Cleaning in the saw, planer, and sorting of dry timber departments was associated with high exposure estimates for several components, whereas work with transportation and stock/finished goods were associated with low exposure estimates for all components. The department-based models explained 21-61% of the total exposure variances, 0-90% of the between worker (BW) variance, and 1-36% of the within worker (WW) variances. The task-based models explained 22-62% of the total variance, 0-91% of the BW variance, and 0-33% of the WW variance. CONCLUSIONS: Exposure determinants in sawmills including department, task, season, and wood type differed for individual components, and explained a relatively large proportion of the total variances. Application of department/task-based exposure prediction models for specific exposures will therefore likely improve the assessment of exposure-response associations.

Occupational exposure during treatment of offshore drilling waste and characterization of microbiological diversity.

The exposure for workers handling and recycling offshore drilling waste are previously not described, and given the potential for exposure to hazardous components, there is a need for characterizing this occupational exposure. In this study five plants recycling offshore drilling waste with different techniques were included. Measurements were conducted in both winter and summer to include seasonal exposure variations. Altogether >200 personal air-exposure measurements for oil mist, oil vapor, volatile organic compounds (VOC), hydrogen sulfide (H2S) and solvents were carried out respectively. Microorganisms related to drilling waste were identified in bulk samples and in stationary air measurements from two of the plants. The exposure to oil mist and oil vapor were below 10% of the current Norwegian occupational exposure limits (OEL) for all measured components. The plants using the Resoil or TCC method had a statistically significant higher exposure to oil vapor than the plant using complete combustion (p-value <0.05). No statistically significant difference was found between the different treatment methods for oil mist. The exposure to solvents was generally low (additive factor < 0.03). Endotoxin measurements done during winter showed a median concentration of 5.4 endotoxin units (EU)/m3. Levels of H2S above the odor threshold of 0.1 ppm were measured at four plants. Both drill mud and slop water contained a high number and diversity of bacteria (2-4 × 104 colony forming unit (CFU)/mL), where a large fraction was Gram-negative species. Some of the identified microorganisms are classified as potentially infectious pathogens for humans and thus might be a hazard to workers.

In vivo analysis of a first-in-class tri-alkyl norspermidine-biaryl antibiotic in an active release coating to reduce the risk of implant-related infection.

Prosthetic joint infection (PJI) is a well-known and persisting problem. Active release coatings have promise to provide early protection to an implant by eradicating small colony biofilm contaminants or planktonic bacteria that can form biofilm. Traditional antibiotics can be limited as active release agents in that they have limited effect against biofilms and develop resistance at sub-lethal concentrations. A unique first-in-class compound (CZ-01127) was assessed as the active release agent in a silicone (Si)-based coating to prevent PJI in a sheep model of joint space infection. Titanium (Ti) plugs contained a porous coated Ti (PCTi) region and polymer-coated region. Plugs were implanted into a femoral condyle of sheep to assess the effect of the Si polymer on cancellous bone ingrowth, the effect of CZ-01127 on bone ingrowth, and the ability of CZ-01127 to prevent PJI. Microbiological results showed that CZ-01127 was able to eradicate bacteria in the local region of the implanted plugs. Data further showed that Si did not adversely affect bone ingrowth. However, bacteria that reached the joint space (synovium) were not fully eradicated. Outcomes suggested that the CZ-01127 coating provided local protection to the implant system in a challenging model, the design of which could be beneficial for testing future antimicrobial therapies for PJI. STATEMENT OF SIGNIFICANCE: Periprosthetic joint infection (PJI) is now commonplace, and constitutes an underlying problem that patients and physicians face. Active release antibiotic coatings have potential to prevent these infections. Traditional antibiotics are limited in their ability to eradicate bacteria that reside in biofilms, and are more susceptible to resistance development. This study addressed these limitations by testing the efficacy of a unique antimicrobial compound in a coating that was tested in a challenging sheep model of PJI. The unique coating was able to eradicate bacteria and prevent infection in the environment adjacent to the implant. Bacteria that escaped into the joint space still caused infection, yet benchmark data can be used to optimize the coating and translate it toward clinical use.

Pneumoproteins in Offshore Drill Floor Workers.

The aim was to assess pneumoproteins and a certain biomarker of systemic inflammation in drill floor workers exposed to airborne contaminants generated during drilling offshore, taking into consideration serum biomarkers of smoking, such as nicotine (S-Nico) and cotinine. Blood samples of club cell protein 16 (CC-16), surfactant protein D (SP-D) and C-reactive protein (CRP) were collected before and after a 14-day work period from 65 drill floor workers and 65 referents. Air samples of oil mist, drilling mud components and elemental carbon were collected in person. The drill floor workers were exposed to a median air concentration of 0.18 mg/m³ of oil mist and 0.14 mg/m³ of airborne mud particles. There were no differences in the concentrations of CC-16 and SP-D across the 14-day work period and no difference between drill floor workers and referents at baseline after adjusting for differences in sampling time and smoking. CRP decreased across the work period. There was a strong association between the CC-16 concentrations and the time of sampling. Current smokers with S-Nico > detection limit (DL) had a statistically significantly lower CC-16 concentration, while smokers with S-Nico

Characterization of air contaminants emitted during laser cutting of carbon fiber-reinforced composite materials.

The emission of ultrafine carbonaceous particles during the laser cutting of fiber-reinforced polymer (CFRP) composite materials was investigated. The study was based on characterization of air contaminants emitted during laser cutting of an epoxy-based CFRP material with respect to particle size distribution, particle morphology, and chemical composition. Results indicate that about 90% of the total particulate mass is present as fine particulate matter with an aerodynamic cut-off diameter of 0.25 µm, and considerable amounts of ultrafine carbonaceous particulate matter dominated by organic carbon are emitted during high-power laser cutting of CFRP.

Exposure to Wood Dust, Microbial Components, and Terpenes in the Norwegian Sawmill Industry.

Sawmill workers are exposed to wood dust (a well-known carcinogen), microorganisms, endotoxins, resin acids (diterpenes), and vapours containing terpenes, which may cause skin irritation, allergy, and respiratory symptoms including asthma. The health effects of most of these exposures are poorly understood as most studies measure only wood dust. The present study assessed these exposures in the Norwegian sawmill industry, which processes predominantly spruce and pine. Personal exposures of wood dust, resin acids, endotoxin, fungal spores and fragments, mono-, and sesquiterpenes were measured in 10 departments in 11 saw and planer mills. The geometric mean (GM) and geometric standard deviation (GSD) thoracic exposures were: 0.09 mg m-3 dust (GSD 2.6), 3.0 endotoxin units (EU) m-3 (GSD 4.9), 0.4 × 105 fungal spores m-3 (GSD 4.2), 2 × 105 fungal fragments m-3 (GSD 3.2), and 1560 ng m-3 of resin acids (GSD 5.5). The GM (GSD) inhalable exposures were: 0.72 mg m-3 dust (2.6), 17 EU m-3 (4.3), 0.4 × 105 fungal spores m-3 (3.8), and 7508 ng m-3 (4.4) of resin acids. The overall correlation between the thoracic and inhalable exposure was strong for resin acid (rp = 0.84), but moderate for all other components (rp = 0.34-0.64). The GM (GSD) exposure to monoterpenes and sesquiterpenes were 1105 µg m-3 (7.8) and 40 µg m-3 (3.9), respectively. Although mean exposures were relatively low, the variance was large, with exposures regularly exceeding the recommended occupational exposure limits. The exposures to spores and endotoxins were relatively high in the dry timber departments, but exposures to microbial components and mono-and sesquiterpenes were generally highest in areas where green (undried) timber was handled. Dust and resin acid exposure were highest in the dry areas of the sawmills. Low to moderate correlation between components (rp ranging from 0.02 to 0.65) suggests that investigations of exposure-response associations for these components (both individually and combined) are feasible in future epidemiological studies.

Correction: Comparison of air samplers for determination of isocyanic acid and applicability for work environment exposure assessment.

Correction for 'Comparison of air samplers for determination of isocyanic acid and applicability for work environment exposure assessment' by Mikolaj Jan Jankowski et al., Environ. Sci.: Processes Impacts, 2017, 19, 1075-1085.

Correction: The stability and generation pattern of thermally formed isocyanic acid (ICA) in air - potential and limitations of proton transfer reaction-mass spectrometry (PTR-MS) for real-time workroom atmosphere measurements.

Correction for 'The stability and generation pattern of thermally formed isocyanic acid (ICA) in air - potential and limitations of proton transfer reaction-mass spectrometry (PTR-MS) for real-time workroom atmosphere measurements' by Mikolaj Jan Jankowski et al., Environ. Sci.: Processes Impacts, 2016, 18, 810-818.

Correction: The applicability of proton transfer reaction-mass spectrometry (PTR-MS) for determination of isocyanic acid (ICA) in work room atmospheres.

Correction for 'The applicability of proton transfer reaction-mass spectrometry (PTR-MS) for determination of isocyanic acid (ICA) in work room atmospheres' by Mikolaj Jan Jankowski et al., Environ. Sci.: Processes Impacts, 2014, 16, 2423-2431.

Pulmonary function and high-resolution computed tomography examinations among offshore drill floor workers.

PURPOSE: The aim of this study was to assess short-term changes in pulmonary function in drill floor workers currently exposed to airborne contaminants generated as a result of drilling offshore. We also aimed to study the prevalence of pulmonary fibrosis using high-resolution computed tomography (HRCT) scans of another group of previously exposed drill floor workers. METHODS: Pulmonary function was measured before and after a 14-day work period in a follow-up study of 65 drill floor workers and 65 referents. Additionally, 57 other drill floor workers exposed to drilling fluids during the 1980s were examined with HRCT of the lungs in a cross-sectional study. RESULTS: The drill floor workers had a statistically significant decline in forced expiratory volume in 1 s (FEV1) across the 14-day work period after adjustment for diurnal variations in pulmonary function (mean 90 mL, range 30-140 mL), while the small decline among the referents (mean 20 mL, range - 30 to 70 mL) was not of statistical significance. Larger declines in FEV1 among drill workers were associated with the fewer number of days of active drilling. There were no signs of pulmonary fibrosis related to oil mist exposure among the other previously exposed drill floor workers. CONCLUSION: After 14 days offshore, a statistically significant decline in FEV1 was observed in the drill floor workers, which may not be related to oil mist exposure. No pulmonary fibrosis related to oil mist exposure was observed.

Transcortical or intracondylar? Which model is accurate for predicting biomaterial attachment in total joint replacement?

Despite four decades of research on material and porous coatings intended for cementless fixation in total joint replacement (TJR), aseptic mechanical loosening unrelated to particulate disease remains a concern. One main question asked is how translational are the animal models used to screen material and porous coatings intended for TJR fixation? Another question is how specific are the translational models at targeting the cementless TJR components that have the highest loosening rates? The hypothesis tested was that the bone response would be different between the two bone types-cortical and cancellous-used in translational animal modeling. The osteoblastic jumping distance (OJD), percent ingrowth, and appositional bone response were measured to assess the response between cancellous and cortical bone at two different anatomical locations, within the same limb. With 500 µm inset, titanium porous coated implants and negative control dinosaur (coprolite) implants were investigated. The data demonstrated that cortical bone had 7 times OJD than cancellous bone. The bone ingrowth data demonstrated 16 times higher bone ingrowth than the cancellous bone. Light microscopy showed predominately fibrous tissue attachment (98%) in cancellous bone. Screening of materials intended for TJR require a translational model predictive of the clinical condition. The results demonstrated that the transcortical model rendered false-positive data. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 578-588, 2018.

Comparison of air samplers for determination of isocyanic acid and applicability for work environment exposure assessment.

Isocyanic acid (ICA) is one of the most abundant isocyanates formed during thermal decomposition of polyurethane (PUR), and other nitrogen containing polymers. Hot-work, such as flame cutting, forging, grinding, turning and welding may give rise to thermal decomposition of said polymers potentially forming significant amounts of ICA. A newly launched dry denuder sampler for airborne isocyanates using di-n-butylamine (DBA) demonstrated build-up of background ICA-DBA over time. Build-up of background ICA-DBA was not observed when stored at inert conditions (Ar atmosphere) for 84 days. Thus, freshly prepared denuders were used. The sampling efficiency of ICA using freshly prepared denuder samplers (0.2 L min-1), impinger + filter samplers (0.5 L min-1) using DBA and 1-(2-methoxyphenyl) piperazine (2MP)-impregnated filter cassette samplers (1 L min-1) was investigated. PTR-MS measurements of ICA were used as a quantitative reference. Dynamically generated standard ICA atmospheres covered the range 5.6 to 640 ppb at absolute humidities (AH) 4.0 and 16 g m-3. Recovered ICA was found to be 73-115% (denuder), 89-115% (impinger + filter) and 62-100% (2MP filter cassette). The method limit of detection (LOD) was equal to an amount of ICA of 24 ng (denuder), 8.9 ng (impinger + filter) and 9.4 ng (2MP filter cassette). The PTR-MS LOD for ICA was 1.8 and 2.8 ppb in atmospheres with an AH of 4 and 16 g m-3. Denuder samplers were used for personal (n = 176) and stationary (n = 31) air sampling during hot-work at six industrial sites (n = 23 workers). ICA was detected above method LOD in 66% and 58% of the personal and stationary samples, respectively. ICA workroom air concentrations were determined to be 1.8-320 ppb (median 12 ppb) (personal samples), and 1.5-44 ppb (median 6.6 ppb) (stationary samples).

Tremor and hand-arm vibration syndrome (HAVS) in road maintenance workers.

OBJECTIVES: The aim of this study was to evaluate postural and rest tremor among workers using vibrating hand tools, taking into account the possible effects of toxicants such as alcohol and tobacco. A further aim was to study workers diagnosed with hand-arm vibration syndrome (HAVS) at the time of examination. METHODS: This study comprises 103 road maintenance workers, 55 exposed to vibrating hand tools (age 41.0 years; range 21-62) and 48 referents (age 38.5 years; range 19-64). They were examined with the CATSYS Tremor Pen®. Exposure to vibrating tools and serum biomarkers of alcohol and tobacco consumption were measured. RESULTS: Cumulative exposure to vibrating tools was associated with increased postural (p < 0.01) and rest tremor (p < 0.05) and with a higher Center Frequency of postural tremor (p < 0.01) among smokers and users of smokeless tobacco. Rest tremor Center Frequency was higher than postural tremor frequency (p < 0.001). CONCLUSIONS: The main findings indicate an association between cumulative exposure to hand-held vibrating tools, tremor parameters and consumption of tobacco products. The hand position is important when testing for tremor. Rest tremor had a higher Center Frequency. Postural tremor was more strongly associated with exposure than rest tremor. The finding of increased tremor among the HAVS subjects indicated that tremor might be a part of the clinical picture of a HAVS diagnosis. As with all cross-sectional studies, inferences should be made with caution when drawing conclusions about associations between exposure and possible effects. Future research using longitudinal design is required to validate the findings of the present study.