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COMPOSTING facilities have been the target of public scrutiny stemming from the concern with nuisance factors as well as perceived health hazards. In many cases, neighborhood complaints regarding odors can escalate into an organized community protest against an existing or sited facility as the concerned public becomes aware of potential negative health effects. Airborne contaminants, particularly Aspergillus fumigatus (AF), have recently become the focus of many of these groups. Several high profile community protests have attempted to identify composting facilities as the cause of a variety of ailments ranging from respiratory distress to nausea to illness in neighborhood pets.
There is a general consensus among experts that exposure to AF at levels in the area surrounding composting facilities poses no risk to otherwise healthy individuals. Workers at compost sites are the most exposed individuals. To date, studies of over several thousand yard trimmings, biosolids, and municipal solid waste composting facilities show no evidence of worker health impact (Millner, et al., 1994). However, as is inherent in risk assessment, there is a level of uncertainty, and as acknowledged by John Haines (BioCycle, April 1995), there is no dose response relationship which delineates a safe concentration of AF.
This lack of certainty, however, is not to imply that testing for AF or other airborne contaminants holds no significance. Testing will not necessarily answer the question regarding the public health implications of AF concentrations, but can determine if the levels of spores in the vicinity are comparable to background levels or if they are indeed elevated. While the composting community continues to study the issue and debate the significance of research results, numerous communities have chosen not to tolerate elevated levels of aerospores.
Although studies have shown that the levels of AF return to background levels within 500 feet of site activity, specific site design, operations, topography, and prevailing winds determine the impact of a particular site. Furthermore, many activities and operations (e.g. farming, landscaping, etc.) produce high levels of AF spores. Ideally, monitoring should be performed in an area in the absence of any site effects -- before site construction and prior to the initiation of composting. This data can be used to establish background or base levels of potential contaminants.
For facilities already in operation, the...