title: Microbial risk assessment for recreational use of the Chicago area waterway system.
abstract: A microbial risk assessment was conducted to estimate the human health risks from incidental contact recreational activities such as canoeing, boating and fishing in the Chicago Area Waterway System (CAWS) receiving secondary treated, but non-disinfected, effluent from three municipal water reclamation plants. Actual concentrations of the pathogens (pathogenic E. coli [estimated], Giardia, Cryptosporidium, adenovirus, norovirus, enteric virus) detected from the waterway field data collection at locations upstream and downstream of the effluent outfall during dry and wet weather conditions within the recreation season were included in the risk assessment. The results under the current treatment scheme with no disinfection indicated that the total expected gastrointestinal illness (GI) rate per 1000 incidental contact recreational exposure events during combined weather (dry and wet) conditions ranged from 0.10 to 2.78 in the CAWS, which is below the eight illnesses per 1000 swimmers considered tolerable by the United States Environmental Protection Agency. Wet weather conditions contribute to elevated pathogen load to the CAWS; therefore this study determined that disinfecting the effluents of three major WRPs that discharge to the CAWS would result in an extremely small reduction in the aggregate recreation season risk to incidental contact recreators.
authors.affiliation: Metropolitan Water Reclamation District of Greater Chicago, Environmental Monitoring & Research Division, 6001 West Pershing Road, Cicero, IL 60804, USA. geeta.rijal@mwrd.org
authors.forename: G
authors.initials: G
authors.lastname: Rijal
authors.forename: J K
authors.initials: JK
authors.lastname: Tolson
authors.forename: C
authors.initials: C
authors.lastname: Petropoulou
authors.forename: T C
authors.initials: TC
authors.lastname: Granato
authors.forename: A
authors.initials: A
authors.lastname: Glymph
authors.forename: C
authors.initials: C
authors.lastname: Gerba
authors.forename: M F
authors.initials: MF
authors.lastname: Deflaun
authors.forename: C
authors.initials: C
authors.lastname: O'Connor
authors.forename: L
authors.initials: L
authors.lastname: Kollias
authors.forename: R
authors.initials: R
authors.lastname: Lanyon
mesh_terms: D002641:Chicago; D004784:Environmental Monitoring; D004926:Escherichia coli / Q000145:classification / Q000302:isolation & purification; D056890:Eukaryota / Q000145:classification / Q000302:isolation & purification*; D005618:Fresh Water / Q000382:microbiology* / Q000469:parasitology / Q000821:virology; D006801:Humans; D010802:Phylogeny; D011998:Recreation; D018570:Risk Assessment; D014780:Viruses / Q000145:classification / Q000302:isolation & purification*; D014872:Water Movements; D014873:Water Pollutants / Q000145:classification / Q000302:isolation & purification*; D014887:Weather
chemical_list: D014873:Water Pollutants