Kari Kulvik Heldal

Upper airway inflammation in waste handlers exposed to bioaerosols

Aims: To examine work associated upper airway inflammation in 31 waste handlers, and to correlate these findings with personally monitored exposure to different bioaerosol components. Methods: Cell differentials, interleukin 8 (IL-8), myeloperoxidase (MPO), and eosinophilic cationic protein (ECP) were examined in NAL (nasal lavage), and swelling of the nasal mucosa was determined by acoustic rhinometry before work start on Monday and the following Thursday. Bioaerosol exposure was determined by personal full shift exposure measurements on Monday, Tuesday, and Wednesday and analysed for total bacteria, fungal spores, endotoxin, and β(1→3)-glucans. Results: The increased percentage of neutrophils from Monday (28%) to Thursday (46%) correlated with increases in ECP (rS = 0.71, p < 0.001) and MPO (rS = 0.38, p < 0.05), and showed a close to significant correlation with nasal swelling (rS = −0.55, p = 0.07). The Thursday levels of neutrophils, MPO, and IL-8 were associated with the exposure to fungal spores (range 0–2.0 × 106/m3) and endotoxin (range 4–183 EU/m3) measured the day before, and the median exposure to β(1→3)-glucans (range 3–217 ng/m3), respectively (rS = 0.47–0.54, p < 0.01). Swelling of the nasal mucosa was associated with the fungal spore and β(1→3)-glucan exposure (rS = 0.58–0.59, p < 0.05). Conclusion: These results are based on a relatively small population, and conclusions must be drawn with care. The results suggested that a moderate exposure to fungal spores, endotoxins, and β(1→3)-glucans during waste handling induced upper airway inflammation dominated by neutrophil infiltration and swelling of the nasal mucosa.

Airway inflammation in waste handlers exposed to bioaerosols assessed by induced sputum

Work-associated lower airway inflammation in waste collectors was examined by induced sputum and correlated with the bioaerosol exposure. Organic waste collectors (n=25) underwent induced sputum collection and spirometry before work on Monday and the following Thursday. Total cells, cell differentials, interleukin (IL)-8 and eosinophilic cationic protein were determined. Personal full-shift exposure measurements were performed Monday, Tuesday and Wednesday and analysed for total bacteria, fungal spores, endotoxins and β(1–3)-glucans. The percentage of neutrophils (46–58%) and the IL-8 concentration (1.1–1.4 ng·mL−1) increased from Monday to Thursday. Forced expiratory volume in one second (FEV1) was significantly reduced on Thursday, and the decrease in FEV1/forced vital capacity correlated with the increase in the percentage of neutrophils. The median exposure to endotoxin (range 7–180 EU·m−3) and β(1–3)-glucan (range 5–220 ng·m−3) was correlated with the increase in IL-8. Bioaerosol exposure during waste collection induced an inflammatory response in the lower airways, characterised by neutrophils and interleukin-8 secretion, that influenced the lung function. The inflammatory response was related to microbial components in the bioaerosol and was more pronounced for endotoxin than β(1–3)-glucan exposure. No associations were found for mould spores or bacteria.

Hazardous peak concentrations of hydrogen sulfide gas related to the sewage purification process.

The concentration of hydrogen sulfide in the atmosphere of a sewage purification plant in Norway was studied. Continuous measurements over several 3-week periods showed that the concentrations generally were lower than 2 ppm, but peak concentrations over 100 ppm were discovered. Rapid onset and decline characterized these peak concentrations, which occurred at regular intervals. Through evaluation of the time pattern of these peaks compared with plant operations, a specific process was identified as the likely causative factor of the spikes. Through simple remedial actions the hydrogen sulfide concentration associated with this activity was reduced from above 100 ppm to less than 2 ppm. Olfactory fatigue to hydrogen sulfide and strong offensive odors from other compounds in the sewage makes smell ineffective for signaling high concentrations. Peak concentrations may therefore pass unnoticed unless detected with continuous measuring equipment. The risk for exposure may be reduced by enclosing processes and through the use of spot extraction ventilation in areas with compacted anaerobic waste material.

Work Tasks as Determinants of Grain Dust and Microbial Exposure in the Norwegian Grain and Compound Feed Industry

OBJECTIVES The grain and compound feed industry entails inevitable risks of exposure to grain dust and its microbial content. The objective of this study was therefore to investigate task-dependent exposure differences in order to create knowledge basis for awareness and exposure reducing measures in the Norwegian grain and compound feed industry. METHODS A total of 166 samples of airborne dust were collected by full-shift personal sampling during work in 20 grain elevators and compound feed mills during one autumn season and two winter seasons. The personal exposure to grain dust, endotoxins, β-1→3-glucans, bacteria, and fungal spores was quantified and used as individual outcomes in mixed models with worker nested in company as random effect and different departments and tasks as fixed effects. RESULTS The exposure levels were highest in grain elevator departments. Exposure to endotoxins was particularly high. Tasks that represented the highest and lowest exposures varied depending on the bioaerosol component. The most important determinants for elevated dust exposure were cleaning and process controlling. Cleaning increased the dust exposure level by a factor of 2.44 of the reference, from 0.65 to 1.58mg m(-3), whereas process controlling increased the dust exposure level by a factor of 2.97, from 0.65 to 1.93mg m(-3). Process controlling was associated with significantly less grain dust exposure in compound feed mills and the combined grain elevators and compound feed mills, than in grain elevators. The exposure was reduced by a factor of 0.18 and 0.22, from 1.93 to 0.34mg m(-3) and to 0.42mg m(-3), respectively, compared with the grain elevators. Inspection/maintenance, cleaning, and grain rotation and emptying were determinants of higher exposure to both endotoxin and β-1→3-glucans. Seed winnowing was in addition a strong determinant for endotoxin, whereas mixing of animal feed implied higher β-1→3-glucan exposure. Cleaning was the only task that contributed significantly to higher exposure to bacteria and fungal spores. CONCLUSION Cleaning in all companies and process controlling in grain elevators were the strongest determinants for overall exposure, whereas seed winnowing was a particular strong determinant of endotoxin exposure. Exposure reduction by technical intervention or personal protective equipment should therefore be considered at work places with identified high exposure tasks.

Long-term occupational outcomes of endotoxin exposure and the effect of exposure cessation

Objective To study the possible respiratory and haematological effects of endotoxin exposure to bacterial single-cell protein (BSCP) in workers during a follow-up period of 5 years including 4 years of exposure and 1 year without exposure. Methods The study included 28 workers examined in 2002–2005 and 1 year after exposure termination in 2007. The arithmetic mean endotoxin exposure was 5800–11 000 EU/m3 among the high exposure group and 390 EU/m3 in the low exposure group. Assessment of lung function included spirometry and gas diffusion in 2003, 2004 and 2007. Rhinometry was performed in 2004 and 2007. Blood analysis included leukocyte cell count and measurement of the acute phase proteins: C-reactive protein, interleukin-6, eosinophilic cationic protein, macrophage inflammatory protein-1α, monocyte chemoattractant protein-1, chemoattractant protein RANTES, platelet-derived growth factor BB, fibrinogen and D-dimer. Results In the low exposure group, but not in the high exposure group, there were significant improvements in both forced vital capacity (FVC) (290 ml) and forced expiratory volume in 1 s (FEV1) (180–210 ml) (p=0.004–0.03) 1 year after the end of exposure. The number of leukocytes and eosinophilic cationic protein and D-dimer levels increased significantly with increasing endotoxin exposures and decreased significantly 1 year after exposure termination. Changes in acute phase proteins suggested exposure-related tolerance. Conclusions An inflammatory tendency during an exposure period of 4 years seems to reverse 1 year after cessation of exposure to endotoxins from a single species. Lung function improved significantly among workers exposed to low levels of endotoxin but not among the highly exposed workers.

Mycotoxins and other fungal metabolites in grain dust from Norwegian grain elevators and compound feed mills

Employees at grain elevators and compound feed mills are exposed to large amounts of grain dust during work, frequently leading to airway symptoms and asthma. Although the exposure to grain dust, microorganisms, β-1→3-glucans and endotoxins has been extensively studied, the focus on the mycotoxin content of grain dust has previously been limited to one or few mycotoxins. Our objective was therefore to screen settled grain dust from grain elevators and compound feed mills for fungal metabolites by LC/MS-MS and explore differences between work places, seasons and climatic zones. Seventy fungal metabolites and two bacterial metabolites were detected. Trichothecenes, depsipeptides, ergot alkaloids, and other metabolites from Fusarium, Claviceps, Alternaria, Penicillium, Aspergillus, and other fungi were represented. The prevalence of individual metabolites was highly variable, and the concentration of each metabolite varied considerably between samples. The prevalence and concentration of most metabolites wer...

Respiratory Effects of Bioaerosols: Exposure-Response Study Among Salmon-Processing Workers

OBJECTIVES The aim of the study was to determine exposure-response relationships in salmon-processing workers. METHODS Cross-shift FEV1, acute respiratory symptoms, and exposure to total protein, parvalbumin and endotoxin were main variables measured during one workweek. Exposure-response relationships were analyzed by Generalized Estimation Equations of cross-week data and by multiple regressions of day-to-day data. RESULTS Exposure levels were higher in those workers who reported use of water hose. GEE showed negative coefficients for interaction between TP exposure and time (days) on cross-week change of FEV1. Multiple regressions showed significant associations between TP levels and cross-shift change of FEV1 and symptoms (cough, chest tightness) only for Monday shifts. CONCLUSIONS A tolerance effect during the course of a workweek is suggested. Use of water hose is a risk process with regard to the liberation of measured components of bioaerosols.

Airway inflammation among compost workers exposed to actinomycetes spores

OBJECTIVES To study the associations between exposure to bioaerosols and work-related symptoms, lung function and biomarkers of airway inflammation in compost workers. MATERIALS AND METHOD Personal full-shift exposure measurements were performed on 47 workers employed at five windrow plants (n=20) and five reactor plants (n=27). Samples were analyzed for endotoxins, bacteria, fungal and actinomycetes spores. Health examinations were performed on workers and 37 controls before and after work on the day exposure was measured. The examinations included symptoms recorded by questionnaire, lung function by spirometry and nasal dimensions by acoustic rhinometry (AR). The pneumoproteins CC16, SP-D and SP-A were measured in a blood sample drawn at the end of the day. RESULTS The levels of endotoxins (median 3 EU/m(3), range 0-730 EU/m(3)) and actinomycetes spores (median 0.2 × 10(6) spores/m(3), range 0-590 × 10(6) spores/m(3)) were significantly higher in reactor plants compared to windrow plants. However, windrow composting workers reported more symptoms than reactor composting workers, probably due to use of respiratory protection. Exposure-response relationships between actinomycetes spores exposure and respiratory effects, found as cough and nose irritation during a shift, was significantly increased (OR 4.3, 95% CI 1.1-16, OR 6.1, 95% CI 1.5-25, respectively, p<0.05) among workers exposed to 0.02-0.3 × 10(6) actinomycetes spores/m3, and FEV1/FVC% decreased cross shift (b=-3.2, SE=1.5%, p<0.01). Effects were weaker in the highest exposed group, but these workers used respiratory protection, frequently limiting their actual exposure. No relationships were found between exposure and pneumoprotein concentrations. CONCLUSIONS The major agent in the aerosol generated at compost plants was actinomycetes spores which was associated with work related cough symptoms and work-shift lung function decrease.

Cross-shift study of exposure–response relationships between bioaerosol exposure and respiratory effects in the Norwegian grain and animal feed production industry

Objective We have studied cross-shift respiratory responses of several individual bioaerosol components of the dust in the grain and feed industry in Norway. Methods Cross-shift changes in lung function and nasal congestion, as well as in respiratory and systemic symptoms of 56 exposed workers and 36 referents, were recorded on the same day as full-shift exposure to the inhalable aerosol fraction was assessed. Exposure–response associations were investigated by regression analysis. Results The workers were exposed on average to 1.0 mg/m3 of grain dust, 440 EU/m3 of endotoxin, 6 µg/m3 of β-1,3-glucans, 17×104/m3 of bacteria and 4×104/m3 of fungal spores during work. The exposure was associated with higher prevalence of self-reported eye and airway symptoms, which were related to the individual microbial components in a complex manner. Fatigue and nose symptoms were strongest associated with fungal spores, cough with or without phlegm was associated with grain dust and fungal spores equally strong and wheeze/tight chest/dyspnoea was strongest associated with grain dust. Bioaerosol exposure did not lead to cross-shift lung function decline, but several microbial components had influence on nose congestion. Conclusions Exposure to fungal spores and dust showed stronger associations with respiratory symptoms and fatigue than endotoxin exposure. The associations with dust suggest that there are other components in dust than the ones studied that induce these effects.

Generation and homogeneity of aerosols in a human whole-body inhalation chamber.

INTRODUCTION A 16 m(3) whole-body exposure chamber for human exposure to aerosols is described. Several modifications of the aerosol generation and distribution system were needed to ensure a stable aerosol concentration in the chamber, especially when a cyclone pre-classifier was used. RESULTS After these modifications, stable aerosol concentrations of aluminium oxide with a volume median diameter of 5.7 microm, and approximately 3 microm when the cyclone was used, could be achieved after 1 h of aerosol generation. Aerosol concentrations of 1-8 mg m(-3) generated without the cyclone could be maintained for at least 2 h after the aerosol level had stabilized. The temporal variability [coefficient of variation (CV)] of the aerosol concentration was 4-6%, while concentrations <1 mg m(-3) showed greater relative variability. The spatial variability at 3.8 mg m(-3) without a volunteer in the chamber was 4.8%. With a volunteer in the chamber who performed 30 min of ergometric cycling during 2 h of aerosol exposure, the exposure estimated by personal sampling was 15-17% lower than monitored with an optical particle counter. The variability of personally measured exposure was higher than of stationary measurements showing CVs of 10-19%. CONCLUSIONS These results show that controlled exposure of human volunteers to a range of concentrations can be achieved with good accuracy in this inhalation chamber. The results compare favourably with other chambers described in the literature. Personal sampling showed lower aerosol concentrations than estimated in an empty chamber and the variability was significantly higher than measured stationary.