Respiratory symptoms among waste-picking child laborers: a cross-sectional study.

This study evaluates respiratory symptoms, lung function, and exposure to airborne particles among waste-picking children. We enrolled 103 waste-picking children at a dump in Managua, Nicaragua and 103 children who do not pick waste. Exposure to airborne particles was assessed by area sampling. Health data were obtained from a questionnaire, clinical examination, and spirometry. Exposure effects were evaluated with multivariate regression analysis. Exposure to particles exceeded national and international standards. Wheezing among children was related to exposure status, with waste-picking children who are both "never highly exposed" and "ever highly exposed" having greater prevalence of wheezing compared to the children who do not pick waste. FEV1 among "ever highly exposed" waste-picking children with wheeze was 13% lower than non-waste-picking children with wheeze. Exposure to small particles was unacceptably high and associated with wheeze and decreased lung function.

Exposure-response relationships for hexahydrophthalic and methylhexahydrophthalic anhydrides with total plasma protein adducts as biomarkers.

OBJECTIVES: This study investigated the exposure-response relationships of hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) and evaluated the applicability of the total plasma protein adducts (TPPA) of these anhydrides as biomarkers of exposure and risk. METHODS: In a cross-sectional study of 139 workers in a plant manufacturing electrical capacitors, the long-term exposure to HHPA and MHHPA was assessed through the quantification of TPPA using gas chromatography-mass spectrometry. Smoking and medical histories were obtained through questionnaires. Work-related symptoms of the eyes and airways were recorded. Specific immunoglobulin (Ig) E (radioallergosorbent test) and IgG (enzyme-linked immunosorbent assay) were determined in serum. RESULTS: The mean level of the TPPA of HHPA was 840 fmol/ml and that of the TPPA of MHHPA was 1700 fmol/ml. There was no correlation between the TPPA of HHPA and the TPPA of MHHPA. Of all the workers, 19% were found to be positive for specific IgE and 17-19% for IgG. Positive associations were observed between HHPA exposure and specific IgE and IgG and between MHHPA exposure and specific IgG. Regarding work-related symptoms, 27% of the workers had symptoms of the nose, 21% had symptoms of the eyes, 11% had symptoms of the lower airways, and 8% had nose bleeding. There were significant exposure-response relationships for symptoms of the eyes and nose for HHPA exposure. CONCLUSIONS: The results show that there is an exposure-response relationship for HHPA both with specific antibodies and with work-related symptoms and down to adduct levels of 40 fmol/ml plasma. In addition, the results elucidate the potential power of TPPA as a relevant index of exposure and risk.

Biological monitoring of exposure to toluene diisocyanate.

OBJECTIVES: Toluene diisocyanate (TDI) is used in the manufacture of polyurethane and is a potent inducer of diseases of the airways. In this study, 2,4- and 2,6-toluenediamine in hydrolyzed urine and plasma were evaluated as biomarkers of exposure to 2,4- and 2,6-TDI, respectively. METHODS: For 81 exposed workers from nine different plants, the personal 8-hour time-weighted-average exposure to TDI was monitored by a filter method with 1-(2-methoxyphenyl)piperazine. In parallel, urinary samples (U1) were collected during the last 4 hours of the workshift. On a different occasion, blood samples and additional urinary samples (U2) were collected from the exposed workers, and also from a reference group consisting of 121 unexposed workers. The biomarker levels were determined in urine and plasma by the use of alkaline hydrolysis. RESULTS: There were strong associations between the personal air and biomarker levels, with correlation coefficients in the range of 0.75-0.88 for the U1 samples and in the range of 0.50-0.78 for the plasma samples. By weighted linear regression, the relations were calculated between the air and biomarker levels. The slopes of the obtained regression curves ranged from 1.8 to 2.7 m3/1 for air-urine and from 2.2 to 2.9 m3/1 for air-plasma, and the intercepts were all close to the origin of the coordinates. Through the extrapolation of these regression curves, biological exposure limits were calculated. CONCLUSIONS: The biological monitoring methods and strategies presented in this report are useful for assessing exposure to TDI in practice.

Cytogenetic and morphologic subgroups of myelodysplastic syndromes in relation to occupational and hobby exposures.

OBJECTIVES: This study investigated the association between occupational and hobby exposure and the risk of myelodysplastic syndromes (MDS) while focusing on differential patterns of clonal chromosome aberrations and morphologic subgroups. METHODS: A case-referent study was conducted with 330 MDS patients investigated cytogenetically in 1976-1993 (cases) and matched referents. Telephone interviews with either the person or a next-of-kin were used. The participation rate of the cases and referents was 85% and 60%, respectively. Information was obtained from the next-of-kin more often for the cases (88%) than for the referents (26%). Occupational hygienists assessed the exposure using interview data on worktasks and hobbies. Associations with disease risk were evaluated for 10 exposures with a logistic regression analysis. RESULTS: The investigated exposures were generally not associated with cytogenetically abnormal MDS. Effect estimates for specific cytogenetic or morphologic subgroups were generally imprecise. Occupational exposure to extremely low-frequency magnetic fields (EMF) was associated with MDS with a normal karyotype [odds ratio (OR) 2.0, 95% confidence interval (95% CI) 1.0-4.0]. The exposure-response association was consistent for intensity but inconclusive for duration. A decreased risk was observed for MDS, irrespective of karyotypic pattern, among farmers and farmhands (OR 0.53, 95% CI 0.35-0.81). CONCLUSIONS: Cytogenetically abnormal MDS was generally not associated with occupational or hobby exposure to known or suspected genotoxic agents. However, exposure prevalences and intensities were low for several agents. An association was suggested between occupational exposure to EMF and MDS with a normal karyotype. Biases due to differential information quality and selective participation cannot be ruled out.

Airways symptoms, immunological response and exposure in powder painting.

OBJECTIVES: Powder painting is an alternative to solvent-based spray painting. Powder paints may contain organic acid anhydrides (OAAs), which are irritants to the airways and may cause sensitisation. The aim of this study was to determine the prevalence of respiratory symptoms and immunological response among powder painters and to describe the exposure to OAAs. METHODS: In all, 205 subjects in 32 enterprises participated: 93 exposed and 26 formerly exposed workers in 25 powder paint shops and 86 unexposed workers. They completed a questionnaire about working conditions and symptoms and took part in a medical examination, which included a lung function test. Urine samples, for determination of two OAAs, and blood samples, for analysis of specific antibodies against the OAAs, were taken. In addition, 33 paint samples were analysed for nine OAAs. RESULTS: The powder painters reported more work-related respiratory symptoms than unexposed subjects did. The prevalence of three or more symptoms was 24% in subjects with low exposure, 44% in highly exposed individuals, 46% in formerly exposed subjects and 19% in unexposed workers. Asthma symptoms were frequent, 7%, 40%, 15% and 2%, respectively. Regression analyses of the lung volumes did not show any influence of exposure. IgG, but not IgE, against the OAAs and metabolites of OAAs was found in some subjects, but no associations with the exposure could be observed. OAAs were found in only small amounts in the paint samples. CONCLUSIONS: The exposure to organic acid anhydrides was estimated to be low, and yet, IgG antibodies to OAA were observed in some subjects. The prevalence of work-related symptoms from the eyes and the airways was relatively high among the powder painters, and these symptoms, but not the lung volumes, were clearly related to exposure. The symptoms were probably caused by irritative properties of the powder paint dust.

Exposure and nasal inflammation in workers heating polyurethane.

OBJECTIVE: To test the hypothesis that exposure to thermal-degradation products of polyurethane (PUR), particularly isocyanates, induced nasal inflammation. METHODS: Thirty-eight workers -14 with a history of work-related nasal symptoms (WRS/Nose), and 15 referents without such history - exposed to sprayed and heated PUR glue, were studied with regard to biomarkers of isocyanate exposure [4,4'-diphenylmethane diisocyanate (4,4'-methylenediphenyl diisocyanate; MDI) and 2,4- and 2,6-toluene diisocyanate (TDI), determined as 4,4'-diphenylmethane (U-MDX) and 2,4- and 2,6-toluene (U-2,4 and U-2,6-TDX) diamine in hydrolysed urine and nasal lavage fluid (NAL)], inflammation [albumin; eosinophilic cationic protein (ECP); myeloperoxidase (MPO) and cells in NAL], serum IgG specific for MDI (S-IgG-MDI) and TDI (S-IgG-TDI), and nose symptoms. Nine unexposed office workers were also examined. RESULTS: The exposure to sprayed and heated PUR glue, especially when heated by gun, was associated with the presence of biomarkers of isocyanate exposure in urine; after work the levels [median (range)] in all workers were: U-MDX 0.32 (

Development, validation and characterization of an analytical method for the quantification of hydrolysable urinary metabolites and plasma protein adducts of 2,4- and 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate and 4,4'-methylenediphenyl diisocyanate.

Occupational exposure to diisocyanates within the plastic industry causes irritation and disorders in the airway. The aim of this study was to develop, validate and characterize a method for the determination of 2,4-toluenediamine (2,4-TDA), 2,6-toluenediamine (2,6-TDA), 1,5-diaminonaphthalene (1,5-NDA) and 4,4'-methylenedianiline (4,4'-MDA) in hydrolysed urine and plasma, and to study the correlation between the plasma and urinary levels of these potential biomarkers of 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 1,5-naphthalene diisocyanate (1,5-NDI) and 4,4'-methylenediphenyl diisocyanate (4,4'-MDI), respectively. Samples were hydrolysed with 0.3 M NaOH at 100 degrees C for 24 h. The diamines were extracted, derivatized with pentafluoropropionic acid anhydride, and quantified by selected ion monitoring on gas chromatography-mass spectrometry. The repeatability and reproducibility of the method were 7-18% and 7-19%, respectively. Dialysis experiments showed that the metabolites of 2,4-TDI, 2,6-TDI, 1,5-NDI and 4,4'-MDI in plasma were exclusively protein adducts. No free diamines were found in urine, indicating that all diisocyanate-related metabolites were in a conjugated form. For each diisocyanate-related biomarker, there were strongly significant correlations (p<0.001) between individual levels of metabolites in plasma and urine, with Spearman's rank correlation coefficient (rs) values of 0.74-0.90. The methods presented here will be valuable for the development of biological monitoring methods for diisocyanates.

A survey of airborne isocyanate exposure in 13 Swedish polyurethane industries.

Exposure to isocyanates can be harmful to workers by causing different disorders of the airways. The main objectives of this study were to survey the personal 8 h time-weighted average exposure to isocyanates at 13 Swedish plants that handled either polyurethane, diisocyanates or both, including four types of manufacturing processes: moulding, continuous foaming, flame lamination and low or no heating processes. A total of 223 air samples were collected for 111 workers with personal air monitoring using a dry filter method with 1-(2-methoxyphenyl)piperazine (2MP) as derivatization reagent. A further 272 stationary samples were collected, using the 2MP method, a modified 2MP method and an impinger method using dibutylamine in toluene. With the applied strategy, a large number of workers were monitored and four industrial environments were compared regarding the isocyanate exposure. All workers were found to be exposed to isocyanates in the range 0.004-5.2 p.p.b. On average, the personal exposure levels in the different types of manufacturing processes were, in decreasing order: continuous foaming > flame lamination > moulding >> low or no heating processes. However, there were variations in exposure levels in plants with similar processes and also between different shifts performing the same tasks. Isocyanic acid, which could not be sampled by the 2MP method used for personal monitoring, was found by short-term stationary monitoring in levels up to 38 p.p.b. in the flame lamination plants.

Determination of isocyanates in air using 1-(2-methoxyphenyl)piperazine-impregnated filters: long-term sampling performance and field comparison with impingers with dibutylamine.

Isocyanates may be harmful to workers and methods for monitoring air exposure in the field are necessary. The main aim of this study was to study the field performance of a method using 1-(2-methoxyphenyl)piperazine (2MP)-impregnated filters, by side-by-side comparison of long-term sampling with consecutive short-term samplings and also by short-term comparisons with other methods. Apart from using 2MP-impregnated filters, air monitoring was also performed by a modified 2MP method (FINMP) and by an impinger method using dibutylamine (DBA), which was the reference method. For short-term sampling the compared methods performed equally well for 2,6-toluenediisocyanate (2,6-TDI) and for isocyanic acid. For 2,4-toluenediisocyanate (2,4-TDI), the DBA method gave approximately 10% higher results according to linear regression than the 2MP method and for phenyl isocyanate, the DBA method gave significantly higher results than both the 2MP and FINMP methods. During long-term sampling (2-4 h) of TDI with the 2MP method, significantly lower levels were found compared with parallel sampling with consecutive short-term samplings. A time-dependent correction factor for long-term sampling was calculated to be 1.7 for 2,4-TDI and 1.5 for 2,6-TDI for 4 h sampling. The long-term sampling performance for other isocyanates was not studied. In conclusion, short-term monitoring shows that the 2MP method slightly underestimates the true air concentration for some of the isocyanates studied, but the error is relatively small considering the variation in exposure. For long-term monitoring the 2MP method can be applied for TDI but, since the method underestimates the concentrations, a correction factor is needed which needs to be corroborated further.