This report describes a linked environmental dispersion, exposure, and health effects model, known as the Spreadsheet Microbial Assessment of Risk: Tool for Biosolids ("SMART Biosolids") which has been developed to assess the relative risk of human infection from direct or indirect exposure to land-applied biosolids. 

SMART Biosolids assesses risk associated with land-applied biosolids through five pathways: (1) inhalation of aerosols from land application sites, (2) consumption of groundwater contaminated by land-applied biosolids, (3) direct ingestion of biosolids-amended soils, (4) ingestion of plants contaminated by land-applied biosolids, and (5) consumption of surface water contaminated by runoff from a land application site. SMART Biosolids focuses on risk to highly exposed individuals who are land application field workers, or residents of homes adjacent to sites. 

The SMART Biosolids model enables wastewater utilities, land applicators, and regulators, to estimate the exposure to pathogenic microorganisms from biosolids land application under a variety of scenarios and thereby gain insight into effective management practices. This report describes how to use SMART Biosolids and provides technical documentation for the mathematical methods used by the model.