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Objective: Between 1995 and 2003 a longitudinal study on miners in two German potash mines was planned and performed by BAuA in collaboration with K+S and IGF. Aim was to correlate exposure data to the results of medical examination of the miners in the respective mines' workforce and to use the detailed exposure investigation as a tool for risk assessment by the company. In this time period a discussion about health effects and the corresponding necessity to lower the existing threshold limits for the components NO and NO(2) was started as well. Whereas the epidemiological aspects of this study are reported elsewhere (Lotz et al., in Int Arch Occup Environ Health, 2006), we discuss the exposure situation in detail in this paper., Methods: In two potash mines in Germany the shift and short time exposure for the components respirable dust, inhalable dust, diesel particulate matter, nitrogen monoxide, nitrogen dioxide, and carbon dioxide was investigated in four separate campaigns. The results are reported and discussed., Results: The miners especially in the production areas of the mines are exposed to a highly correlated mixture of the components though the exposure situation can be regarded as state of the art and representative for the industry., Conclusion: All dose-response discussions must take into account that never only one of the components can be made responsible for an eventually occurring respiratory effect. For reasons of availability of proper measurement equipment limitations for a possible lowering of indicative limit values of the EU are to be observed.

Objectives: The European Co-ordination on Diesel Soot Exposure (ECDSE) working group organised a laboratory inter-comparison which integrated both the sampling and the analytical determination. The aim was to gain more information on the performance of the methods for the determination of diesel particulate matter at workplaces and on their comparability, and to also confirm that the requirements of the European standard EN 482 are fulfilled for this analytical procedure., Methods: Sampling was carried out in a diesel aerosol test chamber where participants used their own sampling devices. Overall, ten sampling exercises at two different concentration levels were performed and both personal air sampling systems and stationary samplers were used. The analytical determination was performed according to the laboratory's own standard procedure., Results: There was good agreement between the laboratories for the determination of organic carbon (OC), elemental carbon (EC) and total carbon (TC). Almost all the results when expressed as a coefficient of variation were in the range +/-30% of the overall means. The results also showed that the coefficient of variation for OC was approximately twice the coefficient of variation for EC. This is not too critical, because existing occupational exposure levels (OELs) are based on the measurement of EC., Conclusions: The inter-comparison showed that existing analytical procedures for the determination of diesel particulate matter at workplaces fulfil the requirements of European standard EN 482. Both personal air samplers and stationary samplers give comparable results. The parameters for the analytical determination are not critical within the range of parameter values presented in this article. Additionally, it may be concluded that the diesel aerosol test chamber used in this exercise is well suited for producing an atmosphere containing a constant and reproducible level of diesel particulate matter.

Methods for the assessment of exposures to diesel exhaust were evaluated, including various biomarkers of internal exposure and early biological effects. The impact of possible biomarkers of susceptibility was also explored. Underground workers (drivers of diesel-powered excavators) at an oil shale mine in Estonia were compared with surface workers. Personal exposures to particle-associated 1-nitropyrene (NP) were some eight times higher underground than on the surface. Underground miners were also occupationally exposed to benzene and polycyclic aromatic hydrocarbons, as indicated by excretion of urinary metabolites of benzene and pyrene. In addition, increased O(6)-alkylguanine DNA adducts were detected in the white blood cells of underground workers, suggesting higher exposure to nitroso-compounds. However, no differences between underground and surface workers were observed in the levels of other bulky DNA adducts determined by 32P-postlabelling, or in DNA damage. The study indicated that smoking, diet and residential indoor air pollution are important non-occupational factors to consider when interpreting biomonitoring results.

Diesel exhaust is considered a probable human carcinogen by the IARC. Biomonitoring of workers occupationally exposed to diesel exhaust was performed to determine their internal burden of diesel associated aromatic compounds. Personal air sampling also allowed to determine the exposure of the miners at their work place towards several polycyclic aromatic hydrocarbons (PAH) and nitro-arenes, the latter of which are thought to be specific constituents of diesel exhaust. For biomonitoring the urine of 18 underground salt miners was collected during and after their shift for 24-hours. half of the 18 miners were smokers. The urinary levels of 1-hydroxypyrene and hydroxylated phenanthrene metabolites were determined as biomarkers of PAH exposure, whereas urinary levels of some aromatic amines were chosen to monitor exposure towards specific nitro-arenes from diesel exhaust like 1-nitropyrene and 3-nitrobenzanthrone and to monitor the human burden by these compounds from inhaled cigarette smoke. Non-smoking workers exposed to diesel exhaust excrete an average level of about 4 micrograms phenanthrene metabolites, whereas the urinary levels in smokers were up to 3-fold higher. In summary the results indicate that (i) diesel exposure led to an increase of PAH metabolism in the workers examined, most probably by an induction of cytochrome P450 (ii) smokers could be identified in accordance with earlier studies by their increased ratio of phenanthrene metabolites derived from 1,2- and 3,4-oxidation and their higher amounts of excreted 1-naphthylamine, and (iii) the excreted amounts of aromatic amines found as metabolites of the nitro-arenes were about 5- to 10-fold higher as one might expect from the levels determined by personal air sampling at the workplace of the individuals.

Objectives: An informal European coordination group organized two round-robin tests on filters collected from environmental, workplace and diluted diesel emissions. Previous inter-laboratory comparisons have shown that experimental samples give reasonably good results in terms of the dispersion around the mean, from all the participating laboratories. However, there were significant differences between the laboratories owing to a narrow distribution of the results within a single laboratory. In order to gain a better understanding of the differences obtained between the laboratories, it was decided to carry out more round-robin tests and to investigate further the possible factors which may influence the results., Methods: The first round-robin (RRT3) was performed on six different samples (eight replicates) analyzed by ten laboratories. The range of loading was 40 to 138 micrograms cm-2 of total carbon (TC). Laboratories used their own thermal procedure parameters. The second round-robin test (RRT4) was performed on three different diluted diesel emissions (two replicates) samples analyzed by 13 laboratories. The range of loading was 21 to 37 micrograms cm-2 TC. Laboratories analyzed samples using imposed temperatures (500, 650 and 800 degrees C) and imposed duration (12 min)., Results: Inter-laboratory coefficients of variation for diluted diesel emission samples were 10% for RRT3 and ranged from 6 to 19% for RRT4. The influence of the desorption temperature was clearly demonstrated and the results tended to show that a desorption temperature of 650 degrees C could be an acceptable compromise. The influence of the organic carbon/elemental carbon (OC/EC) ratio was shown to be insignificant with pure diesel soot samples., Conclusions: It was expected that a significant improvement would be seen in the inter-laboratory dispersion by the use of a common standardized thermal desorption program, but the objectives of these RRTs were only partly reached. This paper provides new information that will be useful in the elaboration of a standardized procedure for the European Normalisation Centre (CEN TC 137 WG2--General requirements for measuring procedures).

Two carbon analysis methods are currently being applied to the occupational monitoring of diesel particulate matter. Both methods are based on thermal techniques for the determination of organic and elemental carbon. In Germany, method ZH 1/120.44 has been published. This method, or a variation of it, is being used for compliance measurements in several European countries, and a Comité Européen de Normalization Working Group was formed recently to address the establishment of a European measurement standard. In the USA, a 'thermal-optical' method has been published as Method 5040 by the National Institute for Occupational Safety and Health. As with ZH 1/120.44, organic and elemental carbon are determined through temperature and atmosphere control, but different instrumentation and analysis conditions are used. Although the two methods are similar in principle, they gave statistically different results in a previous interlaboratory comparison. Because different instruments and operating conditions are used, between-method differences can be expected in some cases. Reasonable agreement is expected when the sample contains no other (i.e., non-diesel) sources of carbonaceous particulate and the organic fraction is essentially removed below about 500 degrees C. Airborne particulate samples from some mines may meet these criteria. Comparison data on samples from mines are important because the methods are being applied in this workplace for occupational monitoring and epidemiological studies. In this paper, results of a recent comparison on samples collected in a Canadian mine are reported. As seen in a previous comparison, there was good agreement between the total carbon results found by the two methods, with ZH 1/120.44 giving about 6% less carbon than Method 5040. Differences in the organic and elemental carbon results were again seen, but they were much smaller than those obtained in the previous comparison. The relatively small differences in the split between organic and elemental carbon are attributed to the different thermal programs used.

Background: Findings from experimental studies on rodents and from epidemiological studies suggest that diesel exhaust may cause lung cancer. There is evidence that in several occupations, e.g., truck drivers and railway workers, the risk of lung cancer increases with duration of employment, and exposure to diesel exhaust provides the most likely explanation for these elevations of risk., Methods: We investigated the association between lung cancer mortality and exposure to diesel exhaust in a cohort study. The cohort comprised 5, 536 male potash miners who were followed from 1970 to 1994. Exposure was assessed from concentration measurements of the total carbon (i. e., elemental and organic carbon in total) in personal dust samples. The concentration values were multiplied by years of exposure to give a quantitative exposure measure. The concentration levels ranged from 0.12 to 0.39 mg/m(3) total carbon in fine dust. Work histories and smoking habit data were obtained from medical company records. Causes of death were ascertained from death certificates., Results: During the follow-up period, 424 deaths were recorded, including 133 of cancer, 38 of lung cancer. The relative risk of lung cancer between two groups with high and low exposure was 2.2 (95% confidence interval 0.8-6.0). With Cox regression, we found a lung cancer relative risk 1.7 (0.5-5.8) after twenty years of exposure. Extensive scrutiny proved smoking not to be a confounder in this study., Conclusions: The principal finding of the study is a doubling of relative lung cancer risk after twenty years of exposure in the workplaces with highest exposure. However, the observed elevation is nonsignificant even at a 90% level. Further follow-up is intended to enhance the study power., (Copyright 1999 Wiley-Liss, Inc.)