University of Arizona (UA) research group says properly treated biosolids pose little if any health risk to the public.Study focused on 19-year analysis tracking pathogens in biosolids from the wastewater stream in Tucson, Ariz.Class A biosolids are treated to the point where pathogens are undetectable and there are no restrictions for fertilizer use.Study's authors include the UA’s Ian Pepper and Charles Gerba, plus researchers from USDA, Loma Linda University, and Drexel University.