A critical analysis of recreational water guidelines developed from temperate climate data and applied to the tropics. (1st March 2020)

• Record Type: Journal Article
• Authors: Verhougstraete, Marc P.; Pogreba-Brown, Kristen; Reynolds, Kelly A.; Lamparelli, Claudia Condé; Zanoli Sato, Maria Inês; Wade, Timothy J.; Eisenberg, Joseph N.S.
• Is Part Of: Water research. Volume 170(2020)
• Publication Date: 2020-03-01
• Subjects: Escherichia coli -- Enterococci -- Quantitative microbial risk assessment -- Beaches -- South America -- Brazil; ml milliliter -- CFU colony forming units -- GI gastrointestinal illness -- WHO World Health Organization -- USEPA United States Environmental Protection Agency -- QMRA Quantitative Microbial Risk Assessment -- CETESB São Paulo State Environmental Company -- NGI NEEAR Gastrointestinal Illness -- NEEAR National Epidemiological and Environmental Assessment; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2019.115294
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Recreational water epidemiology studies are rare in settings with minimal wastewater treatment where risk may be highest, and in tropical settings where warmer temperature influences the ecology of fecal indicator bacteria commonly used to monitor recreational waters. One exception is a 1999 study conducted in São Paulo Brazil. We compared the risk and exposure characteristics of these data with those conducted in the United Kingdom (UK) in the early 1990s that are the basis of the World Health Organization's (WHO) guidelines on recreational water risks. We then developed adjusted risk difference models (excess gastrointestinal illness per swimming event) for children (<10 years of age) and non-children (≥10 years of age) across five Brazil beaches. We used these models along with beach water quality data from 2004 to 2015 to assess spatial and temporal trends in water quality and human risk. Risk models indicate that children in Brazil have as much as two times the risk of gastrointestinal illness than non-children. In Brazil, 11.8% of the weekly water samples from 2004 to 2015 exceeded 158 enterococci CFU/100 ml, the highest level of fecal streptococci concentration measured in the UK study. Risks associated with these elevated levels equated to median NEEAR-Gastrointestinal Illness (NGI) risks of 53 and 96 excess cases per 1000 swimmers in non-children and children, respectively. Two of the five beaches appear to drive the overall elevated NGI risks seen during this study. Distinct enteric pathogen profiles that exist in tropical settings as well as in settings with minimal wastewater treatment highlight the importance of regionally specific guideline development. Highlights: Enterococci are higher in Brazil than UK study, which informed WHO beach guidelines. In Brazil, 11.8% of samples exceeded the highest contamination levels in the UK study. Elevated enterococci levels equates to 96 additional NGI cases in children. Brazil children have twice the risk of gastrointestinal illness than non-children.