The quality of recreational water in Rio de Janeiro, including in the venues hosting Olympic and Paralympic Games events, has been suboptimal because of sewage contamination. – WHO health advice for tourists to the 2016 Olympic and Paralympic games

With the 2016 Rio Olympics in full swing, the indisputably poopy water in which the world’s top athletes are competing has gotten a lot of attention. In the days leading up to the games, in a bid to quiet the global angst for the health of our beloved Olympians, Rio’s waters were deemed “as safe” as Canada’s by Canada’s Chief Medical Officer for the Olympics, Dr. Bob McCormack .

Canadian athletes were quick to point out that this isn’t exactly a high bar, especially in places like Vancouver and Toronto. Canada’s recreational waters have plenty of sewage problems of their own, and many athletes are quite used to training and competing in poo. Athletes face recreational water quality challenges not just in Brazil, but around the world.

Also in the spotlight are the conflicting messages about the quality of Rio’s water. There is not always a consensus on what the acceptable water quality standard is for human contact. The WHO recommends that Olympians and the estimated 500,000 people that came to cheer them on swim at beaches that are classified under Brazilian legislation as Própria (suitable). But there is a lot of confusion surrounding the guidelines that governing bodies use to determine what is Própria and what is not. Some authorities say there is 100% risk of getting violently ill from contact with Rio’s water. Rio state authorities are saying water quality tests of Olympic venues and popular beaches have met state standards.

Let’s take a closer look at international recreational water quality guidelines, and examine how the risk water quality can pose to our health is calculated.

Photo by Bruno Barreto

How do recreational water quality standards minimize the risk of getting sick?

Recreational water quality standards are the minimum protective standard water must meet in order to be considered acceptable for human contact. Standards are established in order to protect people from getting sick from faecal pollution and other contaminants in the water. There are standards for primary contact, such as swimming, secondary contact, like rowing, and non-contact, like riding your bike along the lake shore. Enteric illness (intestinal) is the most frequent adverse health outcome to contact with contaminated water. However, contracting viruses, such as human adenovirus, and other illnesses is also possible, especially in waters that are heavily contaminated with raw or partially treated sewage.

Who sets the bar for water quality at the Olympics?

The World Health Organization (WHO) advises both the International Olympic Committee (IOC) and the Local Olympic Committee (LOC) on water quality. The WHO and PAHO (the WHO’s Pan American Regional Health Organization) also provide technical advice to Brazil. However, Brazil has the last word on determining its own water quality standards, based on the resolution from its National Environmental Council, CONAMA: Conshelo Nacional do Meio Ambiente.

Does water have to meet standards for athletes to compete?


How is the risk of contact with polluted water calculated?

Adequate water quality is still dependent on on-going sanitation investments – Olympic Games Impact Study – Rio 2016

The minimum protective standard for recreational water quality is determined based on a risk factor. Basically, this is the acceptable limit of how many people could get sick from going in the water. Different countries have a different acceptable risk tolerances.

It is currently impossible, epidemiologically-wise, to determine individual risk of infection. So, risk is usually calculated based on how many swimmers per 1000 will get sick. Countries set a limit of how many people per thousand can get sick before the water quality is deemed too polluted and therefore not acceptable for swimming. It is important to note that around the world guidelines for recreation water contact always allow for a degree of health risk.

Brazil: According to the Brazilian legislation specified in CONAMA’s Resolution No. 274/2000, water bodies intended for primary contact (i.e. swimming, and other full body contact activities) are classified as própria (suitable) or imprópria (not suitable) for bathing depending on whether they met or exceeded water quality standards. CONAMA does not clearly define the minimum protective standard used to determine its water quality guidelines.

Canada: Canadian Recreational Water Quality Guidelines are meant to help prevent illness among people in contact with water polluted with faeces. Both fresh and marine water quality guidelines in Canada tolerate a gastrointestinal illness rate of 1-2%. In other words, the minimum protective standard in Canada is: for every 1000 swimmers 10 to 20 people will get tummy troubles following their swim. More than that is considered unacceptable.

USA: The US Environmental Protection Agency’s (EPA) recreational water quality guidelines for both fresh and marine water have two minimum protective standards. In Recommendation 1 the estimated notifiable gastrointestinal illness rate (NGI) per 1,000 primary contact recreators is 36 people. Recommendation 2’s estimated illness rate (NGI) is 32 people per 1,000 primary contact recreators.

What do water quality tests tell us about the risk of illness?

Sewage and stormwater contain many things that can make people sick, including disease-causing pathogens, pharmaceuticals, heavy metals, chemicals, and plastics. However, it is very expensive to test and difficult to analyze all the crap that can be found in sewage and storm water. Testing needs to be done frequently and rapidly in order to be efficient in identifying a problem and therefore warn people about the risk.

The solution, world wide, has been to test for indicator bacteria. All indicator bacteria are faecal (poop) and they are meant to serve as surrogates to the bigger, badder stuff found in sewage. E.coli is considered the best indicator of faecal pollution in freshwater. Intestinal enterococci is the best indicator of contamination in marine water. When levels of indicator bacteria are higher than the minimum protective standard, that translates to an increase in the number of people who will get sick.

However, measuring indicator bacteria isn’t a perfect science as fecal coliforms breakdown quickly in water, whereas viruses can survive for weeks, and even months. This is particularly true in warm climates, such as Brazil. Human adenorivus is of particular concern in recreational waters contaminated with human waste. Adenoviruses are responsible for enteric illnesses and respiratory and eye infections. However, their presence in the water is not directly related to the amount of indicator bacteria present. In other words, recreational water can meet bacterial standards, yet contain dangerous levels of viruses, such as human adenovirus. This is the case in Brazil.

Recently breakthroughs have be made in cost and speed of testing for viruses in recreational water, and many countries are making the move to include the quantification of human adenovirus as an indicator of the virological water quality.

Overview of Recreational Water Quality Standards

The WHO established an international standard for measuring recreational water quality. However, countries have their own national recreational water quality guidelines. Even states and provinces sometimes adopt standards that differ from their national guidelines if they find guidelines that better corresponds to local conditions.

There are standards for fresh, marine, and brackish water. And there are standards for different types of contact with the water: primary (full body contact, like swimming) and secondary (limited water contact, like paddling or sailing).


The WHO provides guideline values for determining the microbiological health of recreational waters. The WHO recommends both sanitary inspection and microbiological water quality assessment are needed to describe the quality of water. However, WHO does not offer universal fresh and marine water quality guidelines, as this is best determined by a nation’s local health authorities. As the WHO states:“There is no universally applicable risk management formula.”


Brazil’s recreational water quality is measured by rate of fecal coliforms and enterococci. E.coli levels are also sometimes measured.

Brazil’s Institute of the Environment (INEA) classifies bathing water quality as própria (suitable) when it meets water quality standards in 80 percent or more of a set of water samples. There is a maximum of 1,000 MPN/100mL faecal coliform average for a series of 5 tests. The single sample maximum is 2500 NMP/100 mL of Thermotolerant (fecal) coliforms. The standard for enterococci is 100 MPN/100mL. Where E.coli is measured, such as at Copacabana Beach, the standard maximum for E.coli is 400 NMP E.coli/100mL.

INEA Recreational Water Quality, August 2016, Rio De Janeiro south and western beaches

The INEA has the following guidelines, based on CONAMA regulations, for categorizing the status of primary contact recreational waters at its beaches. Beaches are assigned a category based on annual test results.

ÓTIMA (optimal/great): max 250NMP/100mL fecal coliforms OR 25 NMP/100 enterococci at least 80% of the time.
BOA (good): max 1000NMP/100mL fecal coliforms OR 100 NMP/100 enterococci at least 80% of the time.
REGULAR (average): max 1000NMP/100mL fecal coliforms OR 100 NMP/100 enterococci between 70% to 80% of the time.
MÁ (bad): max 1000NMP/100mL fecal coliforms OR 100 NMP/100 enterococci between 50% to 70% of the time.
PÉSSIMA (terrible):Does not meet the standards in any of the previous categories.


Canadian Guidelines for Primary Contact in Fresh water
For fresh recreational waters used for primary contact activities, the guideline values are as follows:
Geometric mean concentration (minimum of five samples): ≤ 200 E. coli/100 mL
Single-sample maximum concentration: ≤ 400 E. coli/100 mL

Canadian Guidelines for Primary Contact in Marine water
For marine recreational waters used for primary contact activities, the guideline values are as follows:
Geometric mean concentration (minimum of five samples): ≤ 35 enterococci/100 mL
Single-sample maximum concentration: ≤ 70 enterococci/100 mL

Canadian Guidelines for Secondary Contact in fresh and marine waters
Secondary contact guidelines are admittedly not based on hard scientific evidence. They exist because people engaged in secondary contact activities, like rowing, paddling, sailing, need protection for their health while epidemiologically based guidelines are developed.

In Canada the guidelines for secondary contact was calculated by simply multiplying the primary-contact geometric mean guideline values by 5.

So, for E. coli secondary contact guideline is 1000 per 100 millilitres. For enterococci is works out to be 175 per 100 millilitres.

Freshwater – E.coli: (5X200/100mL) = 1000 E.coli/mL
Marine water – Enterococci: (5X35/100mL) = 175 enterococci/100mL

Photo by RichardBH


The EPA has two sets of recommendations for recreational water quality standards for primary contact recreation, 2 sets of recommendations for secondary contact, and one standard for non-contact recreation.

Recommendation 1 primary contact:

  • Fresh water: Culturable E. coli at a GM of 126 cfu per 100 mL and a statistical threshold value (STV) of 410 cfu per 100 mL measured using EPA Method 1603, or any other equivalent method that measures culturable E. coli.
  • Marine water: Culturable enterococci at a geometric mean (GM) of 35 colony forming units (CFU per 100 milliliters (mL) and an STV of 130 cfu per 100 mL, measured using EPA Method 1600, or any other equivalent method that measures culturable enterococci.
  • Recommendation 2 primary contact:

  • Fresh water: E. coli: Culturable E. coli at a GM of 100 cfu per 100 mL and an STV of 320 cfu per 100 mL measured using EPA Method 1603, or any other equivalent method that measures culturable E. coli.

  • Marine water: Enterococci: Culturable enterococci at a GM of 30 cfu per 100 mL and an STV of 110 cfu per 100 mL, measured using EPA Method 1600, or any other equivalent method that measures culturable enterococci.

  • FOR BOTH RECOMMENDATIONS Duration and Frequency: The waterbody GM should not be greater than the selected GM magnitude in any 30-day interval. There should not be greater than a ten percent excursion frequency of the selected STV magnitude in the same 30-day interval.

    Beach Action Value (BAV)
    The EPA also has Beach Action Value (BAV), a conservative, precautionary tool for making beach notification decisions. This gives vulnerable members of the population, such as children, pregnant women, the elderly, tourists, and others with compromised immune systems better warning against a health risk.

  • Recommendation 1: Enterococci – culturable (fresh and marine)a 70 cfu, E. coli – culturable (fresh)b 235 cfu, Enterococcus spp. – qPCR (fresh and marine)c 1,000 cce
  • Recommendation 2: Enterococci – culturable (fresh and marine)a 60 cfu, E. coli – culturable (fresh)b 190 cfu, Enterococcus spp. – qPCR (fresh and marine)c 640 cce
  • EPA secondary contact guidelines
    Secondary contact category 1 : : 630 cfu/100 mL (E. coli) for freshwater and 175 cfu/100 mL (enterococci) for marine water. Secondary contact in this category is defined as activities, such as fishing, commercial and recreational boating, and limited body contact incidental to shoreline activity. These activities do not involve a significant risk of water ingestion.
    Secondary contact category 2 : 1030 cfu/100 mL (E. coli). Secondary contact activities where the risk of water ingestion occur less frequently than for secondary contact recreation 1 due to physical characteristics of the water body and/or limited public access.
    Non-contact recreation : 2060 cfu/100 mL (E. coli) and 350 cfu/100 mL (enterococci). Activities in this category include ship and barge traffic, birding, and the use hike and bike trails near a water body. Non-contact does not involving a significant risk of water ingestion. Waterbodies defined as non-contact are places where primary and secondary contact recreation should not occur because of unsafe conditions.

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