Man-made vitreous fibers in office buildings in the Helsinki area.

Several sources of man-made vitreous fibers (MMVFs) may exist in an office environment causing irritation symptoms among occupants. In 258 office buildings, the occurrence and density of settled MMVFs on surfaces were measured by two sampling methods. Altogether, 1113 samples of settled dust were collected from surfaces with plastic bags and gelatine tape and were analyzed with a scanning electron microscope and a stereomicroscope, respectively. Tape samples from 68 buildings were collected from frequently cleaned (n = 162) and seldom cleaned (n = 57) room surfaces in 56 and 29 offices, respectively, and from supply air ducts (n = 24) in 10 offices. MMVFs longer than 20 microm were counted with a stereomicroscope. Irritation symptoms were recorded with a questionnaire. More than 60% of the surface dust and almost 90% of the samples collected from supply air ducts contained MMVFs. The density of MMVFs longer than 20 microm ranged from < 0.1 to 5 fiber cm(- 2). The mean density of the MMVFs was about two times higher on the seldom cleaned surfaces than on the frequently cleaned surfaces. The density was usually under 0.2 MMVF cm(- 2) in surface dust of offices without emission sources of MMVFs. The measurements combined with qualitative analysis of settled dust can help to localize relevant sources of fiber emissions. Altogether, in 40% of the buildings, several occupants had repeated irritation symptoms that were verified by occupational health care personnel.

Asbestos fibers in para-aortic and mesenteric lymph nodes.

BACKGROUND: Asbestos fibers are known to accumulate in lung parenchyma and thoracic lymph nodes, but their presence and translocation into the extrapulmonary tissues need clarification. We assessed the presence of asbestos in the para-aortic (PA) and mesenteric (ME) lymph nodes. METHODS: PA and ME lymph nodes and lung tissue from 17 persons who underwent medicolegal autopsy for suspicion of asbestos-related disease and from five controls were analyzed for asbestos fibers using transmission electron microscopy. RESULTS: High concentrations of amphibole asbestos fibers were detected in several lung tissue samples and in the respective PA and ME lymph nodes. The mean concentration for the 10 persons with a lung asbestos content of >/=1 million fibers/g of dry tissue (f/g) was 0.85 (<0.05-4.36) million f/g in the PA lymph nodes and 0.55 (<0.02-2.86) million f/g in the ME lymph nodes. The respective mean values for the 12 persons with a lung asbestos concentration of <1 million f/g were 0.07 for the PA lymph nodes and 0.03 million f/g for the ME nodes. The lung asbestos burden that predicted the detection of asbestos in abdominal lymph nodes was 0.45 million f/g. CONCLUSIONS: In addition to their accumulation in lung tissue, asbestos fibers also collect in the retroperitoneal and the mesenteric lymph nodes. Even low-level occupational exposure results in the presence of crocidolite, amosite, anthophyllite, tremolite, or chrysotile in these abdominal lymph nodes. Our results support the hypothesis of lymph drainage as an important translocation mechanism for asbestos in the human body.

Retroperitoneal and pleural fibrosis in an insulator working in power plants.

We describe a case history of a former insulator who developed concomitant retroperitoneal and pleural fibrosis. In his work, the patient had been exposed on a daily basis to asbestos dust while demolishing and installing pipeline insulations. The heavy asbestos exposure was confirmed by a high level of asbestos content in his autopsy lung sample. We propose that both retroperitoneal fibrosis and diffuse pleural thickening were induced in our patient by an abundant amount of amphibole asbestos fibres found in his lung and retroperitoneal tissues.

El asbesto en el mundo: producción, uso e incidencia de las enfermedades relacionadas con el asbesto / Asbestos in the world: production, use and incidence of asbestos-related diseases

Hasta 20.000 cánceres pulmonares relacionados con el asbesto y 10.000 mesoteliomas se producen anualmente en Europa Occidental, Escandinavia, América del Norte, Japón y Australia. La incidencia del mesotelioma fluctúa entre 14 y 45, con una media de 22 casos/ millón/año en toda la población (sobre los 15 años de edad). En la década de 1970 estos países industrializados habían empleado asbestos entre 2,0 y 5,5 kg/per cápita/año. La mayoría de las muertes por mesotelioma se registra entre trabajadores de la construcción y de astilleros navales. Además, aproximadamente un 5 por ciento de todos los cánceres pulmonares puede atribuirse a exposición ocupacional al asbesto. Aunque los mesoteliomas son normalmente diagnosticados como enfermedades ocupacionales, solamente unos pocos países reconocen los cánceres pulmonares relacionados con el asbesto en la legislación y prácticas de indemnización. No se dispone de datos confiables de Europa Oriental o países en desarrollo de Asia, África o América del Sur.

Up to 20 000 asbestos-related lung cancers and 10 000 mesotheliomas occur annually in Western Europe, Scandinavia, North America, Japan and Australia. The mesothelioma incidence ranges from 14 to 45 with a mean of 22 cases/million/year in the whole population (over 15 years of age). In the 1970's these industrialized countries had used asbestos 2.0 to 5.5 kg/capita/year. Most mesothelioma deaths are registered among construction and shipbuilding workers. In addition, about 5 percent of all lung cancers can be attributed to occupational exposure to asbestos. Although mesotheliomas are usually diagnosed as occupational diseases, only few countries recognize asbestos-related lung cancers in legislation or compensation practice. No reliable data are available from Eastern Europe or developing countries of Asia, Africa or South America.

Behavior of aluminum in aluminum welders and manufacturers of aluminum sulfate--impact on biological monitoring.

OBJECTIVES: The suitability of determining aluminum in serum or urine as a form of biological monitoring was critically assessed. METHODS: Airborne and internal aluminum exposure was assessed for 12 aluminum welders in a shipyard and 5 manufacturers of aluminum sulfate. Particles were characterized with X-ray diffraction and scanning electron microscopy. Aluminum in air and biological samples was analyzed using electrothermal atomic absorption spectrometry. Basic toxicokinetic features were inferred from the data. RESULTS: The mean 8-hour time-weighted average concentration of aluminum was 1.1 (range 0.008-6.1) mg/m(3) for the shipyard and 0.13 (range 0.02-0.5) mg/m(3) for the aluminum sulfate plant. Welding fume contained aluminum oxide particles <0.1 microm in diameter and their agglomerates, whereas bauxite and aluminum sulfate particles ranged from 1 to 10 microm in diameter. The shipyard welders' mean postshift serum and urinary concentrations of aluminum (S-Al and U-Al, respectively) were 0.22 and 3.4 micromol/l, respectively, and the aluminum sulfate workers' corresponding values were 0.13 and 0.58 micromol/l. Between two shifts, the welders' S-Al concentration decreased by about 50% (P<0.01), but their U-Al concentration did not change (P=0.64). No corresponding temporal changes occurred among the aluminum sulfate workers. After aluminum welding at the shipyard had ceased, the median S-Al concentration decreased by about 50% (P=0.007) within a year, but there was no change (P=0.75) in the corresponding U-Al concentration. CONCLUSIONS: About 1% of aluminum in welding fume appears to be rapidly absorbed from the lungs, whereas an undetermined fraction is retained and forms a lung burden. A higher fractional absorption of aluminum seems possible for aluminum sulfate workers without evidence of a lung burden. After rapid absorption, aluminum is slowly mobilized from the lung burden and dominates the S-Al and U-Al concentrations of aluminum welders. For kinetic reasons, S-Al or U-Al concentrations cannot be used to estimate the accumulation of aluminum in the target organs of toxicity. However, using U-Al analysis to monitor aluminum welders' lung burden seems practical.

Exposure to refractory ceramic fibres in the metal industry.

Refractory ceramic fibres (RCF) are used in thermal isolation in the metal industry where high temperatures are regularly employed. Asbestos materials were earlier commonly used for these purposes. In this work, two Finnish steel plants, three foundries and a repair shop were studied for the ceramic fibre exposure of their workers under normal production and during the replacement of oven insulation. Personal and stationary sampling was used together with a novel nasal lavage sampling for the evaluation of personal exposure. Fibres were counted with optical and electron microscopy and they were identified using an energy-dispersive X-ray analyser. Ceramic fibres were found in most production phases [range <0.01-0.29 fibres per cubic centimetre (f cm(-3))]. Considerably higher fibre counts were obtained during the maintenance work (range <0.01-14.2 f cm(-3)). Nasal sampling was found to correlate with the airborne fibre concentrations at the group level. The mean fibre concentrations varied from 34 to 6680 f ml(-1) of lavage liquid. Use of personal respiratory protectors diminished the exposure on the average as analysed in the lavage specimens, but the effect of respirator use did not appear clearly in the results. Because of the heat conditions, the workers used the respirators for a strict minimum period. A considerable exposure to RCF occurs in the studied plants. Its risk should be evaluated and managed more closely in view that the material is carcinogenic. Use of personal respiratory protectors should be encouraged. Their effective use could be verified by the nasal sampling for fibres after the work shift.

Occupational asbestos exposure among respiratory cancer patients in Lithuania.

BACKGROUND: Despite intensive use of asbestos, no cancer case has ever been diagnosed as asbestos related in Lithuania. This paper attempts to estimate the proportion of those occupationally exposed to asbestos among respiratory cancer patients. MATERIAL AND METHODS: Occupational exposure to asbestos was assessed retrospectively for 298 lung cancer and four mesothelioma patients, admitted to the Institute of Oncology, Vilnius. The evaluation was based on personal interview data using an internationally established questionnaire covering most likely activities of asbestos exposure at the workplace. Cumulative exposure to asbestos at work was estimated in fiber years. Lung tissue asbestos fiber burden analysis was conducted by scanning transmission electron microscopy on 23 samples. RESULTS: A cumulative asbestos exposure of > or =25 fiber years was found for 10 lung cancer patients (3.4%). They worked in foundries, construction, installation, shipyard, power plant, railway, asbestos cement, glass and chemical industry. In a further 56 lung cancer patients (18.8%) and for one (25%) mesothelioma patient, a cumulative exposure from 5 to 24.9 fiber years was assessed. Asbestos fibers were detected in 18 cases, the burden ranged from 0.1 to 4.1 million fibers/g dry lung tissue; concentrations exceeding 1 million f/g dry lung tissue were found in four cases. All fibers were chrysotile. CONCLUSIONS: Findings indicate that a fraction (3.4%) of the lung cancer cases could be attributed to heavy occupational exposure to asbestos using the Helsinki criterion of > or =25 fiber years. Therefore, approximately 50 lung cancer cases per year in Lithuania could be asbestos-related compensable occupational diseases.

Evaluation of exposure to man-made vitreous fibers by nasal lavage.

The objectives of this study were to develop a biomonitoring method for the assessment of exposure to man-made vitreous fibers (MMVF), to examine the level of exposure to MMVF in the prefabricated house industry, and to study nasal inflammatory reactions and respiratory symptoms associated with MMVF among workers. Nasal lavage was performed on workers from two factories, and concentrations of MMVF were measured by electron microscopy. Cytokines (IL-6, IL-8, TNF-alpha, and IFN-gamma) were also assayed and inflammatory cells (lymphocytes, eosinophils, neutrophils, and macrophages) were counted microscopically. Concentrations of airborne fibers (longer than 5 microm) were measured for comparison. Moreover, the exposure to MMVF and the related symptoms were studied with a structured questionnaire. In nasal lavage samples, the mean concentration of MMVF (length >1.5 microm) was 3260 f/ mL in Factory 1, 1680 f/mL in Factory 2, and below 500 f/mL in the control group. About 52% of the retained fibers were longer than 100 microm. The group-specific mean concentrations of MMVF in nasal lavage samples correlated with production rates and airborne fiber levels in both plants. The airborne concentrations of MMVF both in the breathing zone and fixed-point samples were low (below 0.1 f/cm(3)). No significant differences in the biological response (inflammatory cells, cytokines) were found between the groups exposed and the control group. The workers complained of some irritation of the skin, eyes, and upper respiratory tract, which could be reduced by appropriate protective equipment. It is concluded that nasal lavage can be used as a biomonitoring method in the assessment of MMVF exposure.

Global use of asbestos and the incidence of mesothelioma.

In Western Europe, Scandinavia, North America, and Australia the manufacture and use of asbestos products peaked in the 1970s. Current incidences of mesothelioma range from 14 to 35 cases/million/year in 11 industrialized countries that had used asbestos 2.0 to 5.5 kg/capita/year about 25 years earlier. A significant linear correlation (r = 0.80, p 0.01) exists between the two variables. Accordingly, about 170 tons of produced and consumed asbestos will cause at least one death from mesothelioma, most often as a consequence of occupational exposure.