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PubMed2003

Reduced exposure to organic solvents by use of water-based paint systems in car repair shops.

OBJECTIVE: The objective of this study was to determine to what extent the substitution of solvent-based paint by water-based paint has reduced potential exposure to organic solvents for spray painters in car repair shops. METHODS: Full-shift personal air sampling (n=79) was carried out over 3 consecutive days in eight car repair shops. Blood samples on the Monday morning (n=26) and at the end of the shift on the Wednesday (n=26), were analysed for organic solvents by headspace techniques. RESULTS: Toluene was the organic solvent detected at the highest geometric mean concentration in air samples when solvent-based paint systems were used (0.8 ppm), whereas xylene was found at the highest level when water-based systems were used (0.25 ppm). Toluene, isopropanol, acetone and butyl acetate were detected at higher concentrations when solvent-based paint was used than when water-based paint was employed. The additive factor, based on Norwegian limit values, was three-times higher for the painters using solvent-based paint (0.15) than for those using water-based paint (0.05). On Wednesday after shift the geometric mean of toluene in blood was significantly higher for the painters using solvent-based paint (0.044 microg/ml) than for the painters using water-based paint (0.007 microg/ml). There was a significant correlation between toluene in personal air samples and toluene in blood samples taken at the end of the shift on the same day. CONCLUSIONS: When solvent-based paint systems were used the additive factor for organic solvent exposure was three-times higher than when water-based systems were employed. The exposure levels of the organic solvents were well below the Norwegian limit values. The significant correlation between the toluene concentration in air and blood samples indicated that the uptake of organic solvents was correspondingly reduced. At the levels of organic solvents presently described the risk of acute and chronic health effects caused by organic solvents is low.

Air Pollutants, Occupational↗
PubMed2005

Occupational noise exposure assessment in intensive swine farrowing systems: dosimetry, octave band, and specific task analysis.

The scientific literature is lacking in published agricultural noise assessments for employees of swine confinement facilities that have included dosimeter data, octave band analysis, or specific task exposure assessments. This study reports on the former three types of noise assessments in the farrowing stage of swine. Dosimeter data on workers revealed all assessments to be greater than 90 decibels measured on the A-scale (dBA), which exceeds the 85 dBA National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL). RELs were exceeded for all of the employees monitored in the swine facility, as well as the part-time employees who power-washed the farrowing rooms. The recorded time-weighted values were actually underestimated slightly because the dosimeters were set to record only noise at 85 dBA and higher.

Agricultural Workers' Diseases↗
PubMed2005

Acute inhalative exposure assessment: derivation of guideline levels with special regard to sensitive subpopulations and time scaling.

Risk assessment for acute airborne exposure to volatile organic compounds (VOCs), including exposure to chemical warfare agents, requires consideration of local and systemic effects at high concentrations. The operating procedure developed by the US Acute Exposure Guideline Level (AEGL) committee has gained special attention, in part because of the international collaboration in the project. The procedure defines three levels (AEGL-1: discomfort; AEGL-2: irreversible or other serious, long-lasting adverse effects; AEGL-3: life-threatening effects or death) for different exposure times (10 and 30 min, and 1, 4 and 8 h). In this article, the methodology for deriving AEGL values is reported. Extending the areas covered by the existing AEGL methodology, sensitive subpopulations are dealt with in more detail. Sensitive persons are expected to suffer from stronger effects when exposed to a given external concentration. Using a kinetic model with the sample substance dichloromethane (DCM), the higher internal exposure of children is quantified and compared to a healthy, young adult. The difference is shown to depend on age, on dose, and on duration of exposure. Furthermore, several ways are presented to derive AEGL values for exposure times which differ from the exposure duration in animal studies ('time scaling'). In comparison to the conventional procedure, the alternative approaches are based on mechanistic models of the toxicodynamic effect. Use of these models results in AEGL values which are biologically justified.

Air Pollutants↗
PubMed2006

The development and regulation of occupational exposure limits in Japan.

The Ministry of Health, Labor and Welfare, on an administrative basis, establishes and supervises the Administrative Concentration Level, which can be viewed as an Occupational Exposure Limit (OEL) legally binding employers to maintain a good working environment. The Japan Society for Occupational Health, on a scientific basis, establishes the Recommended OELs, which can be viewed as a reference value for preventing adverse health effects on individual workers. In the case of carcinogens, Reference Values are recommended instead of OELs, corresponding to lifetime excessive risk of 10(-3) and 10(-4). The former is based on monitoring of the ambient working environment (area monitoring) while the latter is based on the monitoring of the individual worker. The two OELs influence each other in the course of establishment.

Government Regulation↗
PubMedDate not supplied

Applying mathematical modeling to create job rotation schedules for minimizing occupational noise exposure.

This research developed worker schedules by using administrative controls and a computer programming model to reduce the likelihood of worker hearing loss. By rotating the workers through different jobs during the day it was possible to reduce their exposure to hazardous noise levels. Computer simulations were made based on data collected in a real setting. Worker schedules currently used at the site are compared with proposed worker schedules from the computer simulations. For the worker assignment plans found by the computer model, the authors calculate a significant decrease in time-weighted average (TWA) sound level exposure. The maximum daily dose that any worker is exposed to is reduced by 58.8%, and the maximum TWA value for the workers is reduced by 3.8 dB from the current schedule.

Computer Simulation↗
PubMed2001

Aluminum balance in intensive care patients.

Aluminum (Al) is a well known contaminant of intravenous solutions. The aim of the present study was the estimation of the aluminum load in patients of an intensive care unit (ICU). 15 patients with normal renal function took part. The study period was 15 days. Al was measured in serum, 24 h-urine and 132 samples of parenterals. Daily Al doses were recorded. Al balance was calculated on the basis of the iatrogenic Al dose and renal Al excretion. Al analysis was performed by graphite furnace atomic absorption spectrometry (AAS) with Zeeman background correction under careful quality control. Solutions with Al levels >100 microg/l were: calcium salts, additives for parenteral nutrition solutions, antibiotics, acetylcysteine, triflupromazine, catecholamines and colloids. The Al content of solutions for parenteral nutrition ranged from 4.3 to 69 microg/l. Al doses amounted to 46-456 (median 119) microg/d, equivalent to 0.7 to 6.5 (median 1.7) microg/kg b.w. Renal Al excretion ranged from 10.5 to 723.1 microg/d (median 53 microg/d). These amounts partly exceeded the maximal dose (2 microg/kg b.w. per day), recommended by ASPEN/ASCN. Despite of the highly elevated renal Al excretion the median serum concentration of Al was only moderately increased (6.1 microg/l; range: <1.5 to 23.6 microg/l). However, calculations on the basis of the iatrogenic Al dose and renal Al excretion resulted in a net Al uptake (median) of 61 microg/d (maximum: 291 microg/d). Al amounts of this magnitude must be considered potentially harmful in ICU patients, especially with impaired renal function. Parenteral therapy resulted in a considerable Al dose with a positive Al balance in ICU patients. Threshold values for Al contamination of parenterally administered drugs and solutions should be established.

Adolescent↗
PubMed2002

Effects of an external exposure to 200 ppm methyl ethyl ketone on nasal mucosa in healthy volunteers.

OBJECTIVES: To investigate the effects of an acute exposure to 200 ppm methyl ethyl ketone on the nasal mucosa of healthy volunteers. METHODS: Nineteen healthy non-smoking men were exposed to 200 ppm methyl ethyl ketone and to a sham exposure in an exposure chamber, using a cross-over design. Mucociliary transport time was determined with the saccharine test. Interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor-alpha (TNFalpha) were measured in nasal secretions. Subjective symptoms were assessed by questionnaire. RESULTS: Mucociliary transport time was significantly higher (660 vs. 600 s (medians), P = 0.01) after solvent exposure. Concentrations of IL-1beta and IL-8 were insignificantly elevated after exposure (IL-1beta: 83.8 pg/ml vs. 48.1 pg/ml, medians, P = 0.11; IL-8: 14471 pg/ml vs. 11080 pg/ml, P = 0.12), whereas those of IL-6 and TNFalpha remained unchanged. Subjects did not feel any irritation of nasal mucosa. CONCLUSION: Concentrations of organic solvents not exceeding their MAK values can cause subclinical rhinitis. The secretion of proinflammatory cytokines and impairment of mucociliary transport can explain the development of clinical rhinitis in highly exposed subjects.

Adult↗
PubMed2002

Ambient and biological monitoring of coke plant workers -- determination of exposure to polycyclic aromatic hydrocarbons.

OBJECTIVES: The aims of this study were to determine external and internal polycyclic aromatic hydrocarbon (PAH) exposure in a coke plant and to contribute to the evaluation of biological limit values. METHODS: Personal air sampling was carried out on a study population of 24 coke plant workers. In detail, 16 PAHs were determined, among them phenanthrene, pyrene and benzo[ a]pyrene. For the determination of internal exposure, post-shift urine samples from the workers were examined for hydroxylated metabolites of pyrene (1-hydroxypyrene, 1-OHP) and phenanthrene (1-, 2+9-, 3-, 4-hydroxyphenanthrene, 1-, 2+9-, 3-, 4-OHPhe). In both cases, approved HPLC methods were used. RESULTS: The workers were classified into three groups. The group most exposed was that on the top side of the coke oven, with a mean value of 491.2 microg/m(3) for the sum of all sixteen PAHs. The mean value at the bench side was 26.61 microg/m(3), while it was 76.18 microg/m(3) in the group of workers with no dedicated location (=complete area). Both the excretion of 1-OHP and the sum of hydroxyphenanthrenes had the highest mean levels in the top side group of workers (mean: 19.70 microg/g creatinine (crea.) and 39.18 microg/g crea.), followed by the bench-side workers (mean: 7.01 microg/g crea. and 12.95 microg/g crea.) and the whole-area workers (mean: 3.57 microg/g crea. and 8.70 micorg/g crea.). The concentrations of all urinary metabolites correlated significantly with benzo[ a]pyrene (BaP) in the air. CONCLUSIONS: According to these correlations, urinary concentrations of 8 and 11 microg 1-OHP/g crea., respectively 16 and 23 microg/g crea. for the sum of hydroxyphenanthrenes, correspond to BaP concentrations in air of 2 and 5 micorg/m(3), the German technical guiding concentration (TRK value). Our results are in line with others reported in the literature. That means that it should be possible today to define a standard of occupational hygiene and medicine in coke plants using the elimination of hydroxyphenanthrenes and hydroxypyrene in urine as markers for internal PAH exposure.

Adult↗
PubMed2006

Generalized P-values and confidence intervals: a novel approach for analyzing lognormally distributed exposure data.

The problem of assessing occupational exposure using the mean of a lognormal distribution is addressed. The novel concepts of generalized p-values and generalized confidence intervals are applied for testing hypotheses and computing confidence intervals for a lognormal mean. The proposed methods perform well, they are applicable to small sample sizes, and they are easy to implement. Power studies and sample size calculation are also discussed. Computational details and a source for the computer program are given. The procedures are also extended to compare two lognormal means and to make inference about a lognormal variance. In fact, our approach based on generalized p-values and generalized confidence intervals is easily adapted to deal with any parametric function involving one or two lognormal distributions. Several examples involving industrial exposure data are used to illustrate the methods. An added advantage of the generalized variables approach is the ease of computation and implementation. In fact, the procedures can be easily coded in a programming language for implementation. Furthermore, extensive numerical computations by the authors show that the results based on the generalized p-value approach are essentially equivalent to those based on the Land's method. We want to draw the attention of the industrial hygiene community to this accurate and unified methodology to deal with any parameter associated with the lognormal distribution.

Air Pollutants, Occupational↗
PubMed2003

The effect of seat design on vibration comfort.

A field study was done to evaluate different seat designs in the aspect of minimizing vibration transmission and reducing the level of discomfort experienced by drivers subjected to transient vibration. Two seat designs (sliding or fixed in the horizontal direction) were compared in an experiment based on variation of sitting posture, speed, and type of obstacle. The comparison was done by assessing discomfort and perceived motion and by vibration measurement. Ten professional drivers were used as participants. Maximum Transient Vibration Value and Vibration Dose Value were used in the evaluation. The results showed that a sliding seat is superior in attenuating vibration containing transient vibration in the horizontal direction. It was also perceived as giving less overall and low back discomfort compared to a fixed seat.

Automobile Driving↗
PubMed2002

Discriminatory ability of quantitative ultrasound parameters and bone mineral density in a population-based sample of postmenopausal women with vertebral fractures: results of the Basel Osteoporosis Study.

The discriminatory potential to classify subjects with or without vertebral fractures was tested cross-sectionally with different methods for the measurement of bone status in a population-based sample of postmenopausal women. Quantitative ultrasound (QUS) measurement at the calcaneus (Lunar Achilles, Hologic Sahara), the proximal phalanges (Igea Bone Profiler), and measurement of bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA; Lunar Expert) at several anatomic sites was performed in 500 postmenopausal women (aged 65-75 years) randomly selected from the population. In addition, 50 young female subjects (20-40 years old) had QUS measurements and served as controls to express QUS results as T-score values. Radiographs of the lumbar and thoracic spine were performed in the elderly women. Two independent radiologists reviewed the X-rays for the presence of vertebral fractures. Of 486 eligible study participants, no fracture was seen in 396 participants. Single vertebral fractures were observed in 71 subjects; 19 individuals presented multiple fractures. The overall prevalence of vertebral fractures was 18.5%. Participants without vertebral fractures were compared with subjects with vertebral fractures. Normal statistical distributions were found for all bone measurement results. Risk of vertebral fracture in subjects with no and multiple vertebral fracture was estimated using age adjusted odds ratios (ORs) for QUS and dual-energy X-ray absorptiometry (DXA) values. Each SD decrease in bone measurement increased the risk of multiple vertebral fracture by 3.0 (95% CI, 1.6-5.6) for the Achilles stiffness, by 3.8 (95% CI, 1.8-8.2) for the Sahara QUI, 2.1 (95% CI, 1.3-3.4) for the Bone Profiler amplitude-dependent speed of sound (AD-SOS), and 2.1 (95% CI, 1.2-3.9) and 2.4 (95% CI, 1.3-4.3) for DXA lumbar spine and for DXA total hip, respectively. Results of a discriminant analysis showed sensitivities between 84% and 58% and specificities between 72% and 58% for the respective DXA and QUS parameters. Optimum fracture thresholds for QUS measurements derived from this analysis were calculated also. Optimum T-score threshold values for QUS measurements tended to be higher than those for DXA measurements. However, the performance of QUS measurements is at least comparable with DXA measurements in identifying subjects with multiple vertebral fractures randomly selected from the population.

Aged↗
PubMed2000

Indoor viable mold spores--a comparison between two cities, Erfurt (eastern Germany) and Hamburg (western Germany).

BACKGROUND: In eastern Germany, the prevalence of allergies is lower than in western Germany for both children and adults. Several reasons for this fact have been discussed, although it is still not completely understood. One purpose of the epidemiologic study "Indoor and genetic factors in asthma and allergy" (INGA) is to compare exposure to mold spores in two German cities. Therefore, 405 homes in Erfurt (east) and Hamburg (west) were visited twice by trained investigators between June 1995 and May 1997. METHODS: Samples of settled dust were taken by vacuuming from the carpet in the living room. Sieved house dust was diluted and plated on DG18 agar. The analyses were carried out in duplicate in the same laboratory. RESULTS: No significant difference could be shown for the total and for single genera (Alternaria, Aspergillus, Cladosporium, and Penicillium) in concentration of spores of viable fungi in settled house dust between Erfurt and Hamburg. Seasonal variation of the mold picture, with highest values in August, could be identified both indoors and outdoors. CONCLUSIONS: Because outdoor concentration is the main influence on indoor concentration of mold spores from June to October, we recommend sampling from November to May to evaluate exposure to indoor mold spores.

Adult↗
PubMedDate not supplied

[Assessment of cumulative risk of mixtures with multiple target organs].

Humans are exposed to very complex environmental mixtures. In contrast to this reality, most laboratory investigations of mixtures, with exception of mutagenicity assays, have focused on mixtures comprised of a few chemicals. Component-based approaches that use information on the individual chemical contained in the mixture are not by themselves sufficient for complex, environmental mixtures because significant portions of the mixtures mass are unidentified. Assessment of the cumulative risk posed by exposure to multiple chemicals is a problem the USEPA's and FDA's program discuss regularly. In USA the Food Quality Protection Act of 1996 directs the Office of Pesticide Programs to include in its assessments the risk associated with the cumulative effects of pesticides that have a common mode of action. organophosphorus pesticides (OPs) have been the first class addressed, based on the common mechanism of acetylcholinesterase inhibition. Interestingly toxicity studies focussing on component-based analysis of mixtures indicated that for chemicals not sharing the same target and mechanism, the type of combined action or interaction found when each chemical in the mixture was present at clearly toxic effect levels did not predict the response observed when each chemical was present at or below the lowest observed adverse effect level (LOAEL). Moreover, mixtures of chemicals produced toxicity only for those chemicals that showed the same toxic effect on the same target organ when given singly at dose above the LOAEL values. However, end-points chosen in routine toxicity studies do not offer a wide dynamic range of testable, significant responses around and above the NOAEL. So far sensitive methods that detect low level changes have not yet been employed in mixtures testing protocol. Toxicogenomics integrated functional genomics with classical toxicology and we believe that it has great potential to revolutionize mixtures research.

Environmental Exposure↗
PubMed2004

Development of an occupational exposure limit for n-propylbromide using benchmark dose methods.

This paper presents the development of an occupational exposure level (OEL) for n-propylbromide (nPB) using benchmark dose methods. nPB is a non-ozone depleting solvent, proposed under the Significant New Alternatives Policy (SNAP) for use as a precision vapor degreaser. OELs have generally been developed on the basis of a NOAEL or LOAEL and application of uncertainty factors; this paper represents a departure from historic methods. Six recently completed toxicological studies were critically reviewed to identify (1) toxicologically significant endpoints, (2) dose-response information on these endpoints, and (3) uncertainties and limitations associated with the studies. Dose-response data were compiled and entered into the USEPA's benchmark dose software for calculation of a benchmark dose (BMD) and a benchmark dose low (BMDL). Once values were estimated for all relevant studies, they were then incorporated into a weight-of-evidence approach to develop a single BMD and BMDL representative of nPB. This approach is similar to that recently taken by USEPA to develop their own recommended OEL for nPB. USEPA's approach is compared and contrasted with ours, particularly in relation to the application of uncertainty factors (UFs) to generate a final OEL. There are no published criteria for application of UFs in developing an OEL. Although USEPA recommends utilizing a UF of 9, based on intraspecies variability and pharmacokinetic differences between rats and humans, to meet the goal of protecting healthy adult in a workplace setting, no uncertainty factor was deemed necessary for nPB in this paper. Therefore, the BMDL was recommended as the OEL.

Animals↗
PubMed2001

[The new German decree on drinking water].

The Second European Guideline of Drinking Water was published on 3rd November 1998. Notwithstanding good German drinking water standards, as a member country of the European Union, Germany had to transfer this guideline to German law. Therefore the new German decree on drinking water (Trinkwasserverordnung - TrinkwV 2001) was published on 21st May 2001. Basing on recent toxicological findings some of the borderline values have been lowered compared to the previous version. There are problems to realize the new low borderline value for lead; therefore full realization will be ordered not till 2013. The main responsibilities as to the hygienic inspection of water-supplying installations are assigned to the Public Health Office. The owners of water supply installations are notifiable to the Public Health Office. The District with the District Community Physician is the responsible administrative authority to take measures for good and healthy drinking water quality.

Germany↗
PubMed2005

Biological monitoring and Biological Limit Values (BLV): the strategy of the European Union.

Occupational standards concerning allowable concentrations of chemical compounds in the ambient air of workplaces have been established in several countries worldwide. With the integration of the European Union (EU), there has been a need of establishing harmonised Occupational Exposure Limits (OEL). The European Commission Directive 95/320/EC of 12 July 1995 has given the tasks to a Scientific Committee for Occupational Exposure Limits (SCOEL) to propose, based on scientific data and where appropriate, occupational limit values which may include the 8-h time-weighted average (TWA), short-term limits/excursion limits (STEL) and Biological Limit Values (BLVs). In 2000, the European Union issued a list of 62 chemical substances with Occupational Exposure Limits. Of these, 25 substances received a "skin" notation, indicating that toxicologically significant amounts may be taken up via the skin. For such substances, monitoring of concentrations in ambient air may not be sufficient, and biological monitoring strategies appear of potential importance in the medical surveillance of exposed workers. Recent progress has been made with respect to formulation of a strategy related to health-based BLVs.

Air Pollutants, Occupational↗
PubMed2006

Patch test dose-response study of p-phenylenediamine: thresholds and anatomical regional differences.

The elicitation response in allergic contact dermatitis for the hair dye substance p-phenylenediamine (PPD) is dose dependent, but threshold concentrations have not previously been investigated. 15 PPD-sensitive patients participated in a serial dilution 48-hr patch test with PPD using 8 concentrations of PPD ranging from 1 to 10 000 on the upper back. Petrolatum was applied as control. Three concentrations (50, 100 and 500 p.p.m. PPD) were also applied to the retroauricular area and on the lateral aspects of the upper arms. 14 of the 15 participants reacted to one or more of the test samples. The threshold value for 10% of the tested persons (ED10) based on+or stronger reactions for PPD on the back was 38 p.p.m. (CI: 4.3-100). There were no statistically significant differences in the sensitivity of the three anatomical regions. The upper back is a suitable region for patch testing patients with hair dye dermatitis.

Adult↗
PubMed2000

Benchmark concentrations for methylmercury obtained from the Seychelles Child Development Study.

Methylmercury is a neurotoxin at high exposures, and the developing fetus is particularly susceptible. Because exposure to methylmercury is primarily through fish, concern has been expressed that the consumption of fish by pregnant women could adversely affect their fetuses. The reference dose for methylmercury established by the U.S. Environmental Protection Agency was based on a benchmark analysis of data from a poisoning episode in Iraq in which mothers consumed seed grain treated with methylmercury during pregnancy. However, exposures in this study were short term and at much higher levels than those that result from fish consumption. In contrast, the Agency for Toxic Substances and Disease Registry (ATSDR) based its proposed minimal risk level on a no-observed-adverse-effect level (NOAEL) derived from neurologic testing of children in the Seychelles Islands, where fish is an important dietary staple. Because no adverse effects from mercury were seen in the Seychelles study, the ATSDR considered the mean exposure in the study to be a NOAEL. However, a mean exposure may not be a good indicator of a no-effect exposure level. To provide an alternative basis for deriving an appropriate human exposure level from the Seychelles study, we conducted a benchmark analysis on these data. Our analysis included responses from batteries of neurologic tests applied to children at 6, 19, 29, and 66 months of age. We also analyzed developmental milestones (age first walked and first talked). We explored a number of dose-response models, sets of covariates to include in the models, and definitions of background response. Our analysis also involved modeling responses expressed as both continuous and quantal data. The most reliable analyses were considered to be represented by 144 calculated lower statistical bounds on the benchmark dose (BMDLs; the lower statistical bound on maternal mercury hair level corresponding to an increase of 0.1 in the probability of an adverse response) derived from the modeling of continuous responses. The average value of the BMDL in these 144 analyses was 25 ppm mercury in maternal hair, with a range of 19 to 30 ppm.

Animals↗