Ermittlung der inhalativen Belastungen durch Biostoffe im Garten- und Landschaftsbau sowie Anwendung des Risikokonzeptes nach TRBA 400/Determination of inhalation exposure to biological agents in horticulture and landscaping and application of the risk concept according to the TRBA 400

In Germany, around 130,000 people are employed in around 19,600 commercial gardening and landscaping businesses (GaLaBau). Due to the natural microbiological colonization, activities with plants and soil inevitably lead to the exposure of employees to bacteria or moulds or their metabolites. However, qualitative and quantitative exposure data on bioaerosols are hardly available so far, so that a risk assessment for biological substances can hardly be carried out. The measurements therefore focused on activities involving equipment such as lawn mowers, brush cutters, leaf blowers and chainsaws in comparison to background exposure in order to collect relevant data for the industry. The total cell count, the number of cultivable bacteria and mesophilic moulds and the LAL-reactive endotoxins were measured quantitatively and, where possible, qualitatively after stationary and/or personal collection. The inhalation exposure to the parameter total cell count was moderate during lawn mowing, clearing and leaf removal and was 10 times higher than the natural background concentration of 5 x 104 cells per m3 of air. The analysis of the more specific parameters showed a clearer exposure to biological agents. Applying the conventions of TRBA 400, the exposure levels determined and the frequency and duration of activities typical for the sector can be used to derive risks from biological agents. Based on the conventions for lawn mowing and cutting free, an “increased risk” to toxic biological agents and a “high risk” to sensitizing biological agents can be determined for employees. In the activities of leaf removal and tree care, the average exposure to toxic biological agents is below the measured values defined in TRBA 400 for an increased risk, whereas the classification of “increased risk” to sensitizing biological agents is given. Using the convention defined in TRBA 400 for assessing the risk of infection, the statement “no or negligible risk of infection” can be derived. This can be justified by the low incidence of biological agents classified in risk group 2 and the lack of occupational health findings on the incidence of infection in landscaping in connection with inhalation exposures. However, a conclusive statement on the health risk with regard to the risk of infection, the sensitizing and toxic risk due to the higher respiratory exposure is only possible to a limited extent, as no occupational health data has yet been compiled for these activities.