Neurotoxicity of solvent mixtures in spray painters

A multidisciplinary cross-sectional study was carried out in 105 spray painters with long-term solvent exposure (10-44 years) and in 58 control subjects not exposed to solvents. By means of air monitoring the solvent concentrations in the ambient air during spray painting were determined using charcoal and silicagel tubes with pumps and passive samplers. In general, the air concentrations of the individual compounds did not exceed the current limit values (MAK values). Aromatic hydrocarbons like toluene, xylene, ethylbenzene, trimethylbenzene, aliphatic hydrocarbons (e.g., heptane) and acetates (ethylacetate, butylacetate) were determined to be important components of paint solvents. However, in unfavorable work conditions the "exposure index" could exceed the permissible limits two or three times. To assess the body solvent load at the time of examination, biological monitoring (BM) was performed. The main finding was that there was no evidence of neurotoxicologically relevant solvent exposure. Only in the case of methyl hippuric acid in urine spot samples did the spray painters show a higher mean value (80 mg/l) than control subjects (below 20 mg/l), indicating recent xylene exposure. Elevated urinary chromium concentrations (maximum value 29 micrograms/l) were found in 28 spray painters as a result of using zinc chromate-containing wash primers without taking protective measures. To assess the degree of past solvent exposure a special questionnaire was used. This included variables like duration and amount of solvent exposure, the presence of a technical ventilation system, health complaints during painting, etc. Additionally, three "solvent exposure indices' (SEI) were calculated and used for evaluation of "dose-effect relationships.'(ABSTRACT TRUNCATED AT 250 WORDS)     

Individual serum bile acids in apprentice spray painters in association with solvent exposure

The effects of exposure to solvents on serum bile acids were investigated by comparing a group of apprentice vehicle spray painters (exposed group) with one of apprentice electricians. Apprentice spray painters from the study were subdivided into high-and low-solvent-exposure groups. Concentrations of individual serum bile acids (SBA) were measured and compared with conventional liver function tests (LFTs). Total, free, glycine-and taurine-conjugated SBA were consistently found to be present at higher levels in the spray painters than in the electricians, even at the beginning of the apprenticeship. Total SBA tended to increase in spray painters with increasing years of exposure during the apprenticeship, but this was significant at only one time point. No rises were observed over the sampling period in electricians. The mean values of individual and total SBA concentrations were all found to be higher in the high-exposure group than in the low-exposure group, with some differences reaching statistical significane. None of the routine liver biochemistry parameters was different between spray painters and electricians. γ-Glutamyl transferase (GGT) was the only enzyme found to be significantly different between the high-and low-exposure groups, but all values were within the normal range. This study suggests that occupational exposure even to low levels of solvent mixtures results in increases in SBA. The increased SBA may be indicative of a subclinical liver dysfunction. Alternatively, they may reflect solvent exposure only, with the raised levels having no pathologic implication or consequence. The views expressed in this article are those of the authors and do not necessarily reflect those of the National Occupational Health and Safety Commission     

Development of solvent exposure index for construction painters

This article describes methodological approaches for reconstructing long-term occupational exposure to organic solvents among construction painters. A detailed exposure questionnaire was administered to 125 painters to develop a job exposure matrix (JEM). The questionnaire inquired about painting activities with solvent-based paints and use of protection equipment for the previous 25 years in 5-year intervals. Current and historical distributions of solvent air concentrations were assessed for the same time period based on the following information: industrial hygiene measurements, paint composition changes, and VOC emission rate changes from architectural and industrial maintenance coatings. Changes in protection factors of respirators were also assessed. A cumulative solvent exposure index was calculated for each painter through Monte Carlo simulations by combining appropriate input distributions of solvent air concentrations and protection factors of respirators with JEM. Sensitivity simulations revealed that the historical variations in solvent air concentrations had a higher impact on the cumulative solvent exposure index than changes in protection factors for respirators. Fifty-eight percent of painters were classified with a different exposure quartile when the solvent exposure index was used vs. an exposure based only on years using solvent-based paints, suggesting the need for more detailed exposure analysis than just years working when conducting epidemiologic studies for this worker population.     

Neurobehavioral effects and hormones profile among spray painters

A cross-sectional study was conducted in 25 spray painters and 35 control subjects to evaluate neurobehavioral function, and thyroid and reproductive hormones profile. This study indicated higher prevalence of psychological and neurological symptoms, and clinical findings among spray painters when compared with controls. Levels of TSH were significantly (p<0.01) elevated in spray painters over the control group (3.04 +/- 1.53 vs 1.88 +/- 1.07 microIU/ml, mean +/- SD), respectively. Two of the 25 spray painters acquired sub-clinical hypothyroidism, and one subject was detected with overt hypothyroidism. T4 levels were significantly (p<0.05) suppressed in spray painters while T3 was not changed significantly in both the groups. Reproductive hormones (LH, FSH, and testosterone) showed no significant changes in control and spray-painting group. However, two spray painters had abnormally high level of LH (26.43 and 12.22 IU/l; normal range 0.5-10 IU/l). These subjects were also found to have abnormally higher level of FSH (38.63 and 14.11 IU/l; normal range 1.3-11.5 IU/l). An isolated higher level of FSH (39.94 IU/l) was also observed in one spray painter. No abnormality in the level of LH was observed in control group while 3 subjects from this group had abnormally high level of FSH. Testosterone levels were under the normal range (3-12 ng/ ml) in both the groups. This study might suggest that spray painters are at risk of developing neurobehavioral, thyroid and reproductive problems.     

Work-related asthma in automobile spray painters: two case reports

This report describes two patients who had developed asthma after working as automobile painters with isocyanate-based aerosol paint for two years or over. In both patients asthma was confirmed using the standard diagnostic procedure. One of the subjects was atopic. One was ex-smoker and the other had never smoked. Neither had a family history of asthma. The symptoms occurred after workplace exposure lasting two years in one patient and three in the other. As both reported work-relatedness of the symptoms, they underwent serial peak expiratory flow rate (PEFR) measurement and bronchoprovocation testing. Significant work-related changes in PEFR diurnal variations and in non-specific bronchial hyperresponsiveness (NSBH) were observed in one patient, suggesting allergic occupational asthma (OA), while the other patient was diagnosed work-exacerbated asthma (WEA). Our data confirm that spray painting is an occupation with increased risk of respiratory impairment and asthma.     

A dermal model for spray painters. Part I: subjective exposure modelling of spray paint deposition

The discriminative power of existing dermal exposure models is limited. Most models only allow occupational hygienists to rank workers between and within workplaces according to broad bands of dermal exposure. No allowance is made for the work practices of different individuals. In this study a process-based, structured approach has been used to estimate dermal exposure from overspray generated by a spray painting process. Factors for spray technique, object shape and workers' individual work practices involved in the processes of droplet formation and deposition were incorporated into the model. The model was applied to predict dermal exposure of airless spray painters and the results were compared with exposure data. The predicted levels of exposure showed reasonable rank correlation with the measured exposure, although the model tended to over-predict the actual level of exposure. It was concluded that a structured, process-based approach has the potential to produce reliable estimates of dermal exposure. The reliability of exposure models of this type should be explored further and the relationship between the determinants of exposure should be validated by additional field studies.     

Children of male spray painters: weight and length at birth.

The course and outcome of the pregnancies of the wives of 80 spray painters and 80 electronics workers were recorded from birth registers, hospital records, and a questionnaire. The two groups of men had previously been subjected to psychological, psychiatric, neurophysiological, and neurological tests. The variables recorded were occupational exposure to solvents; number of births, ectopic pregnancies, and miscarriages; weight, length, and malformations of the newborn children; duration of the pregnancies; birth complications; and neonatal hospital treatment. The mean length and weight of the children of spray painters at birth were slightly lower than those of the children of electronics workers. No differences were recorded for serious complications of pregnancy, malformations, or clinical course after birth.     

Evaluation of dermal absorption and protective effectiveness of respirators for xylene in spray painters

Objectives To determine the contribution of dermal absorption on the total exposure dose and the performance of respirators in the field for xylene in spray painters. Methods Eighteen male spray painters worked at shipyard were recruited for this study. The subjects were monitored during a 3-day-work period using a repeated-measures study design. Personal exposure to xylene outside and inside mask were collected using two 3 M model 3500 organic vapor monitors, respectively. Urine was collected before and after the work shift and urinary methyl hippuric acid (MHA) was determined. Total 98 of air and urine samples were obtained, respectively. Results Air sampling results showed that workers were primarily exposed to xylene and ethyl benzene. Xylene and ethyl benzene concentrations outside the mask were 52.6 ± 63.7 (mean ± SD) and 33.2 ± 32.4 ppm, and concentrations inside the mask were 2.09 ± 2.74 and 1.79 ± 2.16 ppm, respectively. The median workplace protection factors of respirators for xylene and ethyl benzene were 25.0 and 17.4, respectively. On average, workers could reduce xylene inhalation by 96% and ethyl benzene inhalation by 94% for wearing respirators. A significant correlation (R ² = 0.935; P < 0.001) was found between the WPFs for xylene and ethyl benzene. Total urinary MHA concentration was 240.2 ± 42.3 (mean ± SE) mg/g creatinine, whereas urinary MHA via skin absorption was estimated to be 202.1 ± 40.1 mg/g creatinine. The contribution of dermal absorption to the total exposure dose of xylene was 64 ± 4.3%. Conclusion The present study showed that inhalation of solvent vapors in workers decreased as a result of wearing respirators and dermal exposure became the main contributor to the total body burden of solvents. Because workers had different attitude and behavior to wear respirators, the measured workplace protection factors varied. It is therefore equally important to prevent from being exposed to solvents through skin for shipyard spray painters.     

Children of male spray painters: weight and length at birth.

The course and outcome of the pregnancies of the wives of 80 spray painters and 80 electronics workers were recorded from birth registers, hospital records, and a questionnaire. The two groups of men had previously been subjected to psychological, psychiatric, neurophysiological, and neurological tests. The variables recorded were occupational exposure to solvents; number of births, ectopic pregnancies, and miscarriages; weight, length, and malformations of the newborn children; duration of the pregnancies; birth complications; and neonatal hospital treatment. The mean length and weight of the children of spray painters at birth were slightly lower than those of the children of electronics workers. No differences were recorded for serious complications of pregnancy, malformations, or clinical course after birth.     

Health effects of solvent exposure among dockyard painters: mortality and neuropsychological symptoms

OBJECTIVES: To study mortality and prevalence of neuropsychological symptoms among a cohort of painters known to have been heavily exposed to organic solvents. METHODS: A mortality study of 1292 male painters who had worked in a dockyard in Scotland for > or = 1 year between 1950 and 1992 comprised a nested cross sectional study of 953 surviving painters from the cohort and 953 male non-painters randomly selected from the local population and a case-control study of those with high symptom scores. Mortality, symptoms, and risks associated with painting, adjusting for age, education, smoking, alcohol, and personality were measured. RESULTS: The proportional mortality ratio for all cancers was not increased significantly (110 (95% confidence interval (95% CI) 84 to 143), except for a possible excess of deaths from ischaemic heart disease (132, 105 to 164). Standardised mortality ratios were not significantly increased. Among the 260 surviving painters and 539 community controls who responded to the questionnaire there was a significant excess of symptoms among painters; adjusted relative risk (RR) increased significantly with increasing symptom score. These RRs suggested an exposure-response relation; for a high score (12-22) for all symptoms RR was 2.27 (1.20 to 4.30) for 1-4 years of exposure, 2.42 (1.18 to 4.95) for 5-9 years, 2.89 (1.42 to 5.88) for 10-14 years, and 3.41 (1.82 to 6.36) for 15-41 years, compared with controls. In multivariate analyses, painting exposure, and aging were associated with high symptom scores and there was again an increased risk relative to time worked as a painter. CONCLUSION: This study supports the hypothesis that heavy and prolonged exposure to paint solvents leads to neuropsychological ill health.

 

     

Inhalation exposure to isocyanates of car body repair shop workers and industrial spray painters

As part of a large-scale epidemiological study, occupational isocyanate exposure was assessed in spray-painting environments. The aim was to assess which compounds contribute to isocyanate exposure in car body repair shops and industrial painting companies, and to identify tasks with high risk of isocyanate exposure. Mainly personal task-based samples (n = 566) were collected from 24 car body repair shops and five industrial painting companies using impingers with DBA in toluene. Samples were analysed by LC-MS for isocyanate monomers, oligomers and products of thermal degradation. From the 23 analysed compounds, 20 were detected. Exploratory factor analysis resulted in a HDI, TDI and MDI factor with the thermal degradation products divided over the TDI and MDI factors. The HDI factor mainly consisted of HDI oligomers and was dominant in frequency and exposure levels in both industries. Spray painting of PU lacquers resulted in the highest exposures for the HDI factor (相似文献   

Exposure to lead, cadmium and chromium among spray painters in automobile body repair shops

Environmental and biological monitoring of lead, cadmium and chromium levels in spray painters is reported. All of the study subjects worked in automobile body repair shops that had no standard spraying room. They were divided into 2 groups, those who wore an aerosol-removing respirator while spraying (n=20) and those who did not wear the respirator (n=50). Air in the breathing zone of each subject was sampled and analyzed for lead, cadmium and chromium levels. The subjects' blood lead levels and urinary cadmium and chromium levels were also measured along with those of a control group. The mean environmental and biological levels of these metals between the two groups of the painters were not significantly different (p>0.05). However, the biological levels of the metals were significantly higher in the study groups than in the control group (p<0.01). On-site observations revealed that improper use of an aerosol-removing respirator, lack of an isolated spraying room and poor personal hygiene habits caused the failure to prevent heavy metal exposure among the automobile spray painters.     

Dermal absorption of solvents as a major source of exposure among shipyard spray painters

OBJECTIVE: The purpose of this study was to evaluate the relevance of inhalational and dermal exposure to solvents in shipyard spray painters. Special emphasis was placed on the spatial distribution of dermal exposure and absorption across different regions of the body. METHODS: Fifteen male spray painters were recruited for this study. The subjects were monitored during a 3-day work period using a repeated-measures study design. Air and dermal exposure of solvents were collected each day. Urine was collected before and after the work shift. RESULTS: Air samples showed that the workers were primarily exposed to ethylbenzene and xylene. The concentrations of ethylbenzene and xylene outside the workers' masks were 59.2 +/- 10.4 (mean +/- standard error [SE]) ppm and 29.4 +/- 4.70 ppm, whereas those inside the masks were 7.91 +/- 17.4 ppm and 3.83 +/- 8.22 ppm, respectively. The average mass of ethylbenzene and xylene across the different body regions inside the block units of assembled ships were 305.1 +/- 63.9 mg and 165.6 +/- 34.1 mg. The quantity was, on average, 5.8 and 5.1 times higher than those collected outside the blocks. In both measurements, the highest exposure mass was found on the upper legs, and the lowest exposure mass was found on the back. Principal component analysis (PCA) was used to transform the variables of dermal exposure for all investigated body regions into only one principal component. Multiple regression analyses revealed a significant relationship between dermal exposure to xylene (PCA dermal xyl) and urinary methylhippuric acid (MHA) levels, adjusting for air xylene exposure (R2=0.491, P<0.05). CONCLUSIONS::The present study indicated that dermal exposure to xylene significantly increased the urinary levels of MHA, suggesting that dermal exposure to solvents was an important route among spray painters.     

Solvent exposure and related work practices amongst apprentice spray painters in automotive body repair workshops.

As part of a multidisciplinary study into the health effects of solvents, workplace assessments and airborne solvent vapour monitoring was conducted in 46 spray painting workshops in the Sydney metropolitan area. Breathing-zone samples were taken from 50 apprentices and 14 experienced spray painters. An interview schedule was developed to obtain information about the use of acrylic or two-pack paint systems, the use of engineering controls, the use of personal protective equipment and the availability of material safety data sheets. Contaminants typical of the chemical products used in this industry were encountered (aromatic hydrocarbons, C5-C7 aliphatic hydrocarbons, ketones, esters). The results of airborne solvent monitoring indicate a total solvent exposure in the range 1-99% of a combined Worksafe Australia exposure standard, with a mean of 19%. Solvent exposure was highest when spraying acrylic paint in the open workshop and lowest when spraying two pack paint in a spray booth. Much the same personal protective equipment was available in all workshops, but wide variation in its use was observed. Material safety data sheets were not observed in any of the workshops.     

Influence of organic solvent mixtures on biological membranes

A simple experimental model was used to study the influence of organic solvents and solvent mixtures on the integrity of biological membranes. Radiolabelled membranes were prepared biosynthetically by growing Escherichia coli in the presence of 14C-oleic acid; the bulk of the radioactivity was incorporated into 14C-phosphatidylethanolamine, the predominant phospholipid species in E coli membranes. The radiolabelled bacteria were incubated at 37 degrees C in the presence of solvent, and the mixture filtrated through a Millipore 0.45 micron filter. This filtration retained radiolabel associated with the bacteria, and only radiolabel released as a result of solvent action was allowed through the filter. The radioactivity in the filtrate was then counted and expressed as a percentage of the total radioactivity. Results showed that aliphatic alcohols released membrane constituents in relation to their hydrocarbon chain length (1-propanol greater than 2-propanol greater than ethanol greater than methanol); the effects of aliphatic alcohols were potentiated by acetone, ethyl methyl ketone, ethylene glycol, and N,N'-dimethylformamide, and the effects of ethanol were potentiated by 1-butanol, benzyl alcohol, and ethylacetate. These findings point to the possibility that certain mixtures of organic solvents are more damaging to membranes than the components of the mixture would indicate, and suggest that the experimental model used might help in showing mixtures that are particularly harmful.     

A dermal model for spray painters. Part II: estimating the deposition and uptake of solvents

The contribution of dermal exposure to the total body burden of a given chemical is difficult to assess. However, it is possible that as regulatory pressures lead to reductions in inhalation exposure, the proportion of uptake via the dermal route will increase. This study brings together recent work in the field of dermal exposure to provide a model to estimate both exposure and uptake of solvents through the skin. Using spray painters as an example, the process of modelling exposure is described from identifying the determinants of exposure through to calculating the flux of solvent through the stratum corneum and thus the total dermal uptake. Results from a range of exposure scenarios are presented and areas requiring further research and validation are highlighted. The model should allow the estimation of combined dermal and inhalation exposure to solvents in both current work situations and retrospective epidemiological studies. Furthermore, it is envisaged that the model may provide the basis for generic assessment of dermal exposure and uptake.     

Increased uptake of serotonin in platelets from car painters occupationally exposed to mixtures of solvents and organic isocyanates

Twelve car painters occupationally exposed to mixtures of solvents and organic isocyanates were investigated concerning serotonin uptake in platelets. The data from the exposed workers were compared to data from a reference group consisting of 50 nonexposed volunteers. The mean platelet count in whole blood of the exposed workers was markedly lower than the corresponding value of the reference group. Three workers had values below the lower limit of the 95% tolerance interval of the referents. In both groups the serotonin transport strictly obeyed Michaelis-Menten's simple saturation kinetics. Nine of the twelve exposed workers had uptake rates which were significantly higher (p = 0.05) than those of the referents. The obtained data suggest that the present method may be used to reveal early organ damage, prior to the appearance of clinical symptoms, due to intermittent exposure to organic solvents and isocyanates.     

Influence of organic solvent mixtures on biological membranes.

A simple experimental model was used to study the influence of organic solvents and solvent mixtures on the integrity of biological membranes. Radiolabelled membranes were prepared biosynthetically by growing Escherichia coli in the presence of 14C-oleic acid; the bulk of the radioactivity was incorporated into 14C-phosphatidylethanolamine, the predominant phospholipid species in E coli membranes. The radiolabelled bacteria were incubated at 37 degrees C in the presence of solvent, and the mixture filtrated through a Millipore 0.45 micron filter. This filtration retained radiolabel associated with the bacteria, and only radiolabel released as a result of solvent action was allowed through the filter. The radioactivity in the filtrate was then counted and expressed as a percentage of the total radioactivity. Results showed that aliphatic alcohols released membrane constituents in relation to their hydrocarbon chain length (1-propanol greater than 2-propanol greater than ethanol greater than methanol); the effects of aliphatic alcohols were potentiated by acetone, ethyl methyl ketone, ethylene glycol, and N,N'-dimethylformamide, and the effects of ethanol were potentiated by 1-butanol, benzyl alcohol, and ethylacetate. These findings point to the possibility that certain mixtures of organic solvents are more damaging to membranes than the components of the mixture would indicate, and suggest that the experimental model used might help in showing mixtures that are particularly harmful.