The exposure to organic dust at workplaces of composting facilities is associated with adverse acute and chronic respiratory health effects, including MMI, chronic bronchitis, and an accelerated decline of FVC%. The pattern of health effects differs from those at other workplaces with exposures to organic dust possibly due to high concentrations of thermo-tolerant/thermophilic actinomycetes and filamentous fungi at composting plants.
Objectives-In a cross sectional study, work related health complaints and diseases of 58 compost workers and 53 biowaste collectors were investigated and compared with 40 control subjects. Levels of specific IgG antibodies to moulds and bacteria were measured as immunological markers of exposure to bioaerosols. Methods-With a standardised protocol, the participants of the study were interviewed for work related symptoms, conditions of exposure to bioaerosols at their workplaces, exposure to bioaerosols from other sources, atopic diseases, and smoking habits. They were clinically examined by physicians specialised in occupational medicine. Also, concentrations of specific IgG antibodies against antigens of moulds and actinomycetes occurring regularly at these workplaces were measured and compared with the health complaints of the workers. Results-Compost workers had significantly more symptoms and diseases of the airways (p=0.003) and the skin (p=0.02) than the control subjects. Health complaints of biowaste collectors did not diVer significantly from those of the control group. Subjects with atopic diseases were underrepresented in the compost workers (p=0.003). Significantly increased antibody concentrations against fungi and actinomycetes were measured in workers at composting plants. The concentrations in biowaste collectors did not diVer significantly from those in the control subjects. A significant association between the diseases and increased antibody concentrations were found in the compost workers. Conclusion-The high exposure to bioaerosols of compost workers is significantly associated with a higher frequency of health complaints and diseases as well as higher concentrations of specific antibodies against moulds and actinomycetes. A healthy worker eVect is indicated by the underrepresentation of atopic diseases among the compost workers compared with biowaste collectors and the control group.
BackgroundInhalation of high concentrations of zinc oxide particles (ZnO) may cause metal fume fever. In an earlier human inhalation study, no effects were observed after exposure to ZnO concentrations of 0.5 mg/m3. Further data from experimental studies with pure ZnO in the concentration range between 0.5 and 2.5 mg/m3 are not available. It was the aim of this experimental study to establish the concentration-response relationship of pure nano-sized ZnO particles.MethodsSixteen healthy subjects were exposed to filtered air and ZnO particles (0.5, 1.0 and 2.0 mg/m3) for 4 h on 4 different days, including 2 h of cycling with a low workload. The effects were assessed before, immediately after, and about 24 h after each exposure. Effect parameters were symptoms, body temperature, inflammatory markers and clotting factors in blood, and lung function.ResultsConcentration-dependent increases in symptoms, body temperature, acute phase proteins and neutrophils in blood were detected after ZnO inhalation. Significant effects were detected with ZnO concentrations of 1.0 mg/m3 or higher, with the most sensitive parameters being inflammatory markers in blood.ConclusionA concentration-response relationship with nano-sized ZnO particles in a low concentration range was demonstrated. Systemic inflammatory effects of inhaled nano-sized ZnO particles were observed at concentrations well below the occpational exposure limit for ZnO in many countries. It is recommended to reassess the exposure limit for ZnO at workplaces.
Diesel engine exhaust particles (DEP) contribute substantially to ambient air pollution. They cause acute and chronic adverse health effects in humans. Biodiesel (rapeseed oil methyl ester. RME) is used as a "green fuel" in several countries. For a preliminary assessment of environmental and health effects of RME, the particulate-associated emissions from the DEP of RME and common fossil diesel fuel (DF) and their in vitro cytotoxic and mutagenic effects were compared. A test tractor was fuelled with RME and DF and driven in a European standard test cycle (ECE R49) on an engine dynamometer. Particle numbers and size distributions of the exhausts were determined at the load modes "idling" and "rated power". Filter-sampled particles were extracted and their cytotoxic properties tested using the neutral red assay. Mutagenicity was tested using the Salmonella typhimurium/microsome assay. Despite higher total particle emissions, solid particulate matter (soot) in the emissions from RME was lower than in the emissions from DF. While the size distributions and the numbers of emitted particles at "rated power" were nearly identical for the two fuels, at "idling" DF emitted substantially higher numbers of smaller particles than RME. The RME extracts caused fourfold stronger toxic effects on mouse fibroblasts at "idling" but not at "rated power" than DF extracts. The extracts at both load modes were significantly mutagenic in TA98 and TA100. However, extracts of DF showed a fourfold higher mutagenic effect in TA98 (and twofold in TA100) than extracts of RME. These results indicate benefits as well as disadvantages for humans and the environment from the use of RME as a fuel for tractors. The lower mutagenic potency of DEP from RME compared to DEP from DF is probably due to lower emissions of polycyclic aromatic compounds. The higher toxicity is probably caused by carbonyl compounds and unburned fuel, and reduces the benefits of the lower emissions of solid particulate matter and mutagens from RME.
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