| Contents Notes |
This preliminary risk assessment focuses on the probability of human infection from protozoa and halminths, usually referred to as parasites, in municipal sewage sludge applied to land. It is based on the Pathogen Risk Assessment computer model and methodology described in Pathogen Risk Assessment for Land Application of Municipal Sludge. The report documents (1) the results of a literature review designed to find data on parasites required by the pathogens methodology, and (2) the results of numerous site-specific computer simulations, running the Pathogen Risk Assessment model with a wide range of values for the parameters required. The parameters required for parasites are density in sludge, transport and die-off rates in environmental media, and minimum infective dose. Locations selected for site-specific application of the model included counties in California, Florida, Iowa, New Mexico, Tennessee, and Washington. Model runs predicted probabilities of infection of a human receptor exposed to pathogenic parasites by a variety of pathways arising from the use of sludge-amended soil to grow vegetable crops, lawns, or forage for cattle used for meat or milk. Data gaps are identified and research priorities are recommended. |
