Printer Friendly

The water quality in RIO highlights the global public health concern over untreated sewage.


From the spread of the Zika virus, to the polluted waters in Rio de Janeiro, media reports have highlighted health concerns in Brazil. An editorial in the New York Times (Cox 2016), along with other media reports of high levels of sewage contamination in Rio's recreational waters, caused wide-ranging concerns about the safety of sailing, rowing, and other open-water events at the 2016 Olympic Games (Brooks and Barchfield 2015). Such concerns seemed well grounded, because in August 2015, members of the U.S. rowing team reported stomach illness following a trial competition on a Rio lake that the team doctor suspected was due to water pollution (Mazloumsaki and Brocchetto 2015). For both Zika and water quality, media attention has focused on athletes and the role of the International Olympic Committee. However, exposure goes beyond athletes to everyone who uses water, including tourists and most importantly local residents. That much of Rio's human sewage goes untreated is in no way unusual for urban environments, especially in low- and middle-income countries (LMICs). It is estimated that 1.5 billion people worldwide have sewage connections with no treatment (Baum et al. 2013). Even in higher-income countries where sewage is often treated to a high degree, environmental contamination from sewage occurs when treatment is bypassed, for example, during storm water overflows, which are frequent in some settings (Sato et al. 2013).

Monitoring Recreational and Drinking Water

The news coverage about Rio highlights the need for a better understanding of exposures and risks associated with untreated or partially treated sewage that exposes billions to dangerously high levels of pathogens worldwide. Sewage-contaminated waters contain a wide range of potentially pathogenic bacteria, protozoa, and viruses. The World Health Organization (WHO 2003) and the U.S. Environmental Protection Agency (U.S. EPA 2012) provide general recommendations for monitoring drinking water and recreational waters, largely based on data from developed countries in temperate climates. These include simple as well as targeted tests for bacteria commonly found in human feces, such as Escherichia coli or Enterococcus, which are used to gauge the level of contamination and to infer potential health risks (Wade et al. 2003). However, the use of these bacteria as markers has been questioned in tropical environments because of a concern that they tend to grow or have more prolonged survival in warm environments than in the climates the recommendations are based on (Byappanahalli and Fujioka 2004; Stewart et al. 2008).

In a rare study in a tropical developing country, a recent analysis found that the bacterial indicators used by the WHO and other agencies were, in fact, a good measure of human risk for locations like Rio, because many of the popular beaches in Rio and in other cities in developing countries worldwide are often directly affected by untreated sewage (Lamparelli et al. 2015). In this prospective cohort study, Lamparelli et al. (2015) conducted a study of beach goers (N = 16, 637) who were exposed to sewage-contaminated waters on five beaches in Sao Paulo, Brazil. The research team recruited families during a 1-month period (9 January through 6 February 1999) who were then followed up through a telephone interview. The evidence provided by Lamparelli et al. (2015) that currently used bacterial indicators are appropriate in tropical beaches under the influence of untreated sewage, where their validity has been questioned, has important implications for regulation and practice worldwide.

However, recent media reports from Rio, as well as at least one scientific study, have suggested that not only are standard bacterial indicators inadequate, but that there may be a need to test for specific viral pathogens in Rio waters (Brooks 2015; Victoria et al. 2014). In our view, the proposed focus on testing for a relatively narrow range of viral pathogens is misguided, because the most critical factor in preventing health risks under conditions of untreated-sewage discharges is to identify the degree of sewage contamination rather than the presence of a small subset of the wide range of pathogens of potential concern. To identify the degree of sewage contamination, standard tests for bacterial or viral indicator organisms, which are commonly found in high densities in sewage are just as good, cheaper, and more reliable in settings where resources are limited (WHO 2003). These tests can usefully be combined with sanitary surveys to understand the source and nature of discharges to the water bodies and to inform decision-making about remediation.

Under some circumstances, there may be a need for additional testing beyond fecal indicator organisms to better characterize water quality and to understand human health risks. For example, in settings where exposure to fecal contamination is low because of advanced sewage treatment, standard bacterial indicators could die off more rapidly than many viral and protozoan pathogens (Rose et al. 1996). In tropical environments with advanced sewage treatment, where water temperatures are higher, persistence or possible growth of bacterial indicators may also call for alternative measures, supplemental measures, or both. Under these conditions, alternative monitoring approaches and indicators that are a) better indicators of viral contamination, b) more resistant to advanced treatment technologies, and c) more sensitive at lower levels of pathogens, may be warranted (Savichtcheva and Okabe 2006). Also, in cases where sites are affected not by sewage point sources but by diffuse and variable non-point sources, such as where latrines and septic systems provide sanitation services to human populations, standard bacterial indicators may not be sufficient to identify pathogen contamination. Under these circumstances it may be important to determine the specific source or type of fecal contamination using source-specific genetic markers.

Exposure to Untreated Sewage is a Global Problem

Exposure to human feces, including untreated sewage and the pathogens associated with it, is a global problem and extends beyond recreational waters and the 2016 Olympics. The risks of acute and chronic disease attributable to exposure to human excreta are largely unknown. Over the past decades, there has been a dramatic increase in the number of people using improved drinking water sources (such as village wells with hand pumps) worldwide, and the Millennium Development Goal (MDG) objective to halve the proportion of those using unimproved drinking water sources was achieved ahead of the deadline. In contrast, the number of people without access to improved sanitation is high (Baum et al. 2013), and the sanitation objective fell short by a large margin as the MDGs drew to a close in 2015 (Fuller et al. 2016; WHO/UNICEF 2015). We believe that the general lack of data on the associated risks is cause for concern--especially with the global population growth and the even more rapid growth in the number of households, which are outstripping the ability to treat and manage human feces (Bartram et al. 2012).


This situation illustrates the complexity of testing and monitoring sewage in the environment. Standard bacterial indicators were predictive of gastrointestinal illness in one of the few recreational water studies that measured health risks in a tropical setting where sewage is largely untreated (Lamparelli et al. 2015). On the surface, it may seem beneficial and informative to test for viral pathogens, but the additional expertise and resources to conduct these tests may divert resources from routine monitoring without substantially increasing our understanding of the risks or improving health outcomes. The global trends toward urbanization have intensified our need for water and have created new emerging hazards such as antimicrobial resistance. We should, therefore, view the water quality issues highlighted by the media attention to the Rio Olympics as a wake-up call. The Rio condition has also reminded us that the development of the associated sewerage and sewage-treatment infrastructures is a very costly, long-term enterprise that cannot be activated for rapid effect. It is urgent that we invest in improving our management, including the treatment of human excreta and sewage and the development of tools to track and optimize these efforts.

Joseph N.S. Eisenberg, (1) Jamie Bartram, (2) and Timothy J. Wade (3)

(1) Department of Epidemiology, University of Michigan, Ann Arbor Michigan, USA;

(2) The Water Institute, Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA;

(3) United States Environmental Protection Agency, Chapel Hill, North Carolina, USA

Address correspondence to J.N.S. Eisenberg, Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Arbor MI, USA 48109. Telephone: (734) 615-1625. E-mail:

We would like to thank E. August and A. Egorov for their insightful comments on this commentary.

The views expressed in this article are those of the authors and do not represent those of the U.S. Environmental Protection Agency, the University of Michigan, or the University of North Carolina.

The authors declare they have no actual or potential competing financial interests.

Note to readers with disabilities: EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact Our staff will work with you to assess and meet your accessibility needs within 3 working days.


Bartram J, Elliott M, Chuang P. 2012. Getting wet, clean, and healthy: why households matter. Lancet 380 (9837):85-86.

Baum R, Luh J, Bartram J. 2013. Sanitation: a global estimate of sewerage connections without treatment and the resulting impact on MDG progress. Environ Sci Technol 47(4):1994-2000.

Brooks B. 2015. AP test: Rio Olympic water badly polluted, even far offshore [news story]. Associated Press, 2 December 2015.

Brooks B, Barchfield J. 2015. AP investigation: Olympic teams to swim, boat in Rio's filth [news story]. Associated Press, 30 July 2015.

Byappanahalli M, Fujioka R. 2004. Indigenous soil bacteria and low moisture may limit but allow fecal bacteria to multiply and become a minor population in tropical soils. Water Sci Technol 50(1):27-32.

Cox L. 2016. Olympians shouldn't swim through sewage [news story]. New York Times, Opinion Pages. New York, NY, 5 May 2016.

Fuller JA, Goldstick J, Bartram J, Eisenberg JN. 2016. Tracking progress towards global drinking water and sanitation targets: a within and among country analysis. Sci Total Environ 541(2016):857-864.

Lamparelli CC, Pogreba-Brown K, Verhougstraete M, Sato MI, de Castro Bruni A, Wade TJ, et al. 2015. Are fecal indicator bacteria appropriate measures of recreational water risks in the tropics: a cohort study of beach goers in Brazil? Water Res 87(2015):59-68.

Mazloumsaki S, Brocchetto M. 2015. U.S. rowers' illness highlights questions over Rio Olympics water quality [news story]. CNN World, 11 August 2015. americas/brazil-olympics-us-rowing-squad/ [accessed 11 August 2015].

Rose JB, Dickson LJ, Farrah SR, Carnahan RP. 1996. Removal of pathogenic and indicator microorganisms by a full-scale water reclamation facility. Water Res 30(11):2785-2797.

Sato T, Qadir M, Yamamoto S, Endo T, Zahoor A. 2013. Global, regional, and country level need for data on wastewater generation, treatment, and use. Agricultural Water Management 130(2013):1-13.

Savichtcheva O, Okabe S. 2006. Alternative indicators of fecal pollution: relations with pathogens and conventional indicators, current methodologies for direct pathogen monitoring and future application perspectives. Water Res 40(13):2463-2476.

Stewart JR, Gast RJ, Fujioka RS, Solo-Gabriele HM, Meschke JS, Amaral-Zettler LA, et al. 2008. The coastal environment and human health: microbial indicators, pathogens, sentinels and reservoirs. Environ Health 7(suppl 2):S3, doi: 10.1186/1476-069X-7-S2-S3.

U.S. EPA (U.S. Environmental Protection Agency). 2012. Recreational Water Quality Criteria. Report No. 820-F-12-058. Washington DC:U.S. EPA, Office of Water.

Victoria M, Fumian TM, Rocha MS, Dalmao F, Leite JP, Girones R, et al. 2014. Gastroenteric virus dissemination and influence of rainfall events in urban beaches in Brazil. J Appl Microbiol 117(4):1210-1218.

Wade TJ, Pai N, Eisenberg JN, Colford JM, Jr. 2003. Do U.S. Environmental Protection Agency water quality guidelines for recreational waters prevent gastrointestinal illness? A systematic review and meta-analysis. Environ Health Perspect 111(8):1102-1109.

WHO (World Health Organization). 2003. Guidelines for Safe Recreational Water Environments. Volume 1: Coastal and Fresh Waters. Geneva, Switzerland:WHO. water_sanitation_health/publications/srwe1/en/ [accessed 3 May 2016].

WHO/UNICEF. 2015. Progress on Sanitation and Drinking Water: 2015 Update and MDG Assessment. Geneva, Switzerland:WHO. on_Sanitation_and_Drinking_Water_2015_Update_.pdf [accessed 4 April 2016].
COPYRIGHT 2016 National Institute of Environmental Health Sciences
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2016 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Perspectives: Brief Communication
Author:Eisenberg, Joseph N.S.; Bartram, Jamie; Wade, Timothy J.
Publication:Environmental Health Perspectives
Geographic Code:3BRAZ
Date:Oct 1, 2016
Previous Article:Managing and mitigating the health risks of climate change: calling for evidence-informed policy and action.
Next Article:TSCA 2.0: a new era in chemical risk management: after decades of dysfunction, the Toxic Substances Control Act has been overhauled with provisions...

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters