Assessing the probability of infection by Salmonella due to sewage sludge use in agriculture under several exposure scenarios for crops and soil ingestion Flávio Krzyzanowski Jr a, ⁎, Marcelo de Souza Lauretto b , Adelaide Cássia Nardocci c , Maria Inês Zanoli Sato d , Maria Tereza Pepe Razzolini c a Instituto Federal de Educação, Ciência e Tecnologia de Sao Paulo, R. Pedro Vicente 625, São Paulo, SP 01109-010, Brazil b EACH — Escola de Artes, Ciências e Humanidade, Universidade de Sao Paulo, R. Arlindo Bettio, 1000, São Paulo, SP 03828-000, Brazil c Faculdade de Saude Publica, Universidade de Sao Paulo, Av. Dr Arnaldo 715 1° andar, Sao Paulo, SP 01246-904, Brazil d CETESB — Companhia Ambiental do Estado de Sao Paulo, Av. Prof. Frederico Hermann Jr, 345, São Paulo, SP 05459-900, Brazil HIGHLIGHTS • Nine scenarios for evaluating Salmonella risk by using sewage sludge in soil • Regrowth of Salmonella spp. in soil and internalization in vegetables • Annual risk for consumers of vegetables and field workers • Sanitary and health measures need to be implemented. GRAPHICAL ABSTRACT abstract article info Article history: Received 12 February 2016 Received in revised form 17 May 2016 Accepted 18 May 2016 Available online xxxx Editor: D. Barcelo A deeper understanding about the risks involved in sewage sludge practice in agriculture is required. The aims of the present study were to determine the annual risk of infection of consuming lettuce, carrots and tomatoes cul- tivated in soil amended with sewage sludge. The risk to agricultural workers of accidental ingestion of sludge or amended soil was also investigated. A Quantitative Microbial Risk Assessment was conducted based on Salmonella concentrations from five WWTPs were used to estimate the probability of annual infection associated with crops and soil ingestion. The risk of in- fection was estimated for nine exposure scenarios considering concentration of the pathogen, sewage sludge di- lution in soil, variation of Salmonella concentration in soil, soil attachment to crops, seasonal average temperatures, hours of post-harvesting exposure, Salmonella regrowth in lettuce and tomatoes, Salmonella inhi- bition factor in carrots, crop ingestion and frequency of exposure, sludge/soil ingestion by agricultural workers and frequency of exposure. Annual risks values varied across the scenarios evaluated. Highest values of annual Keywords: Risk assessment Salmonella Science of the Total Environment 568 (2016) 66–74 ⁎ Corresponding author. E-mail addresses: fkjuniormeister@gmail.com (F. Krzyzanowski), marcelolauretto@usp.br (M. de Souza Lauretto), nardocci@usp.br (A.C. Nardocci), misato@sp.gov.br (M.I.Z. Sato), razzolini@usp.br (M.T.P. Razzolini). http://dx.doi.org/10.1016/j.scitotenv.2016.05.129 0048-9697/© 2016 Published by Elsevier B.V. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv