Exposure to Wood Dust, Microbial Components, and Terpenes in the Norwegian Sawmill Industry

Abstract

Sawmill workers are exposed to wood dust (a well-known carcinogen), microorganisms, endotoxins, resin acids (diterpenes), and vapours containing terpenes, which may cause skin irritation, allergy, and respiratory symptoms including asthma. The health effects of most of these exposures are poorly understood as most studies measure only wood dust. The present study assessed these exposures in the Norwegian sawmill industry, which processes predominantly spruce and pine. Personal exposures of wood dust, resin acids, endotoxin, fungal spores and fragments, mono-, and sesquiterpenes were measured in 10 departments in 11 saw and planer mills. The geometric mean (GM) and geometric standard deviation (GSD) thoracic exposures were: 0.09 mg m−3 dust (GSD 2.6), 3.0 endotoxin units (EU) m−3 (GSD 4.9), 0.4 × 105 fungal spores m−3 (GSD 4.2), 2 × 105 fungal fragments m−3 (GSD 3.2), and 1560 ng m−3 of resin acids (GSD 5.5). The GM (GSD) inhalable exposures were: 0.72 mg m−3 dust (2.6), 17 EU m−3 (4.3), 0.4 × 105 fungal spores m−3 (3.8), and 7508 ng m−3 (4.4) of resin acids. The overall correlation between the thoracic and inhalable exposure was strong for resin acid (rp = 0.84), but moderate for all other components (rp = 0.34–0.64). The GM (GSD) exposure to monoterpenes and sesquiterpenes were 1105 µg m−3 (7.8) and 40 µg m−3 (3.9), respectively. Although mean exposures were relatively low, the variance was large, with exposures regularly exceeding the recommended occupational exposure limits. The exposures to spores and endotoxins were relatively high in the dry timber departments, but exposures to microbial components and mono-and sesquiterpenes were generally highest in areas where green (undried) timber was handled. Dust and resin acid exposure were highest in the dry areas of the sawmills. Low to moderate correlation between components (rp ranging from 0.02 to 0.65) suggests that investigations of exposure–response associations for these components (both individually and combined) are feasible in future epidemiological studies.

Assessment of airborne endotoxin in sandstorm dust and indoor environments using a novel passive sampling device in Al Zulfi city, Saudi Arabia – Establishing threshold exposure levels

“…Further, a report by Basinas et al (2017) collected 38 personal exposure measurements from dairy farmers and reported that dairy farm workers can be exposed to high and variable levels of inhalable dust and endotoxin (900 EU/m 3 ) and consequently such workers may be at risk of respiratory disease. Similarly research into such diverse working environments as greenhouses with plants, sawmill industries, waste composting plants, poultry farming and metalworking industries, show comparable airborne endotoxin ranges ( Dahlman-Höglund et al, 2016 , Gioffrè et al, 2018 , Gutarowska et al, 2015 , Straumfors et al, 2018 , Thilsing et al, 2015 ).…”

The Inhalable Mycobiome of Sawmill Workers: Exposure Characterization and Diversity

“…Fungal diversity in relation to traditional exposure measurements. Measurements of dust masses and fungal spore counts in microscopy are common methods in occupational exposure assessments and have been published for the same workers evaluated in the present study (1). The HTS technology provides a further, more detailed picture of the exposure, and it is interesting to compare the fungal community pattern (richness, diversity, abundance) of the personal samples with air sample volume, dust masses, and fungal spore counts.…”

“…The flow rate was calibrated and recorded using a digital flow meter (Defender; SKC Inc., Eighty-Four, PA, USA) before and after sampling. The workers carried two sampling cassettes loaded with a polycarbonate (PC) filter (pore size, 1.0 m) in parallel, one for microscopic spore counts in field emission scanning electron microscopy (FESEM), as described previously (1,37), and one for DNA isolation and sequencing. Other workers carried sampling cassettes with a polyvinylchloride (PVC) filter (pore size, 5 m) for measurement of the aerosol mass by gravimetric analyses, as described previously (1).…”

“…The workers carried two sampling cassettes loaded with a polycarbonate (PC) filter (pore size, 1.0 m) in parallel, one for microscopic spore counts in field emission scanning electron microscopy (FESEM), as described previously (1,37), and one for DNA isolation and sequencing. Other workers carried sampling cassettes with a polyvinylchloride (PVC) filter (pore size, 5 m) for measurement of the aerosol mass by gravimetric analyses, as described previously (1). The mean of the dust masses by department, season, company, and day was used to allocate representative dust mass values to the workers selected in the present study (see Table S1 in the supplemental material).…”

“…Fungal spore exposure in the Norwegian sawmill industry was recently shown to be highly variable and exceeded the recommended OEL of 1 ϫ 10 5 fungal spores/m 3 for 38% of the workers (1), suggesting that fungal exposure may contribute to adverse health effects in this industry. The microbial complexity of the exposure, such as variations in fungal species domination, composition, and richness, is, however, unknown.…”