Bathing water guide

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How to asses the microbiological risks of natural bathing waters, and the health effects they have? Data on the water and bathing behaviour must be possible to give to the model as input.


The model below is already functional. However, there is still work to do to ensure that the input data the model uses is accurate.

The contamination classes used in the model are not comparable to the bathing water classification used by the EU. To see the microbe concentrations for each of the contamination classes, see page Pathogen concentrations in raw water.


Bathing water contamination:

Beach goers per day:

Microbe concentration of bathing water

Campylobacter concentration (microbes/l):

E.coli O157:H7 concentration (microbes/l):

Rotavirus concentration (microbes/l):

Norovirus concentration (microbes/l):

Cryptosporidium concentration (microbes/l):

Giardia concentration (microbes/l):

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Pages containing the data and codes used by the model
Page What data or code the page has What is it used for Other observations
Op_en7961 Bathing water guide (this page) Data on time spent in water and amount of water swallowed during bathing, as well as the age distribution of beach-goers. The amount of water swallowed per hour is multiplied by time spent in water to find the total water swallowed per bathing event. The age distribution is used, because people of different ages swallow different amounts of water and spend different lengths of time in water. Also susceptibility to diseases and their severity changes with age, so burden of disease and cases of illness are calculated for each age group.
Op_en7953 Pathogen concentrations in raw water The amounts of pathogens in different (raw) water classes If the user has chosen a water contamination class, the amounts of each pathogen in water of that contamination class is found here. If the user has given the amounts of pahtogens by hand, the data on this page isn't used and the given values are used instead. The data on this page is also used in Water guide, and it is better suited to be used as data on rawa water for drinking water than for bathing water. This is alos why the classification does not match the bathing water classification used by the EU.
Op_en7947 Case burden of waterborne microbes Case burdens of different pathogens, or how severe and long-lasting the diseases caused by them are This data is used to calculate the health detriments caused by the pathogens in bathing water.
Op_en7957 Health impacts of waterborne microbes Doesn't contain data, only code
Op_en7948 ERF of waterborne microbes Describes the exposure-response functions for the pathogens These functions tell how likely an individual is to get sick with different exposures. This and the exposure are used to estimate the cases of illness.
Op_en2261 HIA Code that combines all of the above The code on the page uses exposure, exposure-response functions and the case burdens to calculate the total burdens caused by pathogens in bathing water. From here it is also possible to calculate the number of people getting ill from bathing water. These are the final results of the model.


Amount of water swallowed, ml/h

Reference Adults Children Notes
Dufour et al. 2006 [1] 0 - 70,67 (avg 21,33) 0 - 205,33 (avg 49,33) They measured cleaning chemicals added to the pool water from the bathers' urine
Dufour et al. 2017 [2] 12,4 (CI95 11-14) 6-10-year-olds: 23,9 (CI95 17-33)

11-15 vuotiaat: 23,7 (CI95 19-30)

Same as previous, but with a bigger sample size
Suppes et al. 2013 [3] 0 - 50,9 (avg 3,5) 0,9 - 105,5 (avg 25,7) Also measuring chemicals in urine
Suppes et al. 2016 [4] 0 - 60,6 (avg 6,3) 0 - 105,5 (avg 24,2) Same methods as the previous one
Schets et al. 2011 [5] 20 - 30 28 Questionnaire. These values are for fresh water, but the study also looked at values for sea and pool water. Values are averages (20 for women, 30 for men).
DeFlorio-Barker et al. 2018 [6] n. 0 - 114 (keskiarvo n. 16) n. 0.7 - 144 (keskiarvo n. 27) Quistionnaire, simulations of amounts of swallowed water based on behavior and Dufour (2017) values.

Time spent in water (min)

Reference Adults Children Notes
Dufour et al. 2017 50,3 (CI95 49-52) 6-10-year.olds: 95,9 (CI95 88-104)

11-15-year-olds: 55,8 (CI95 55-59)

The study participants were asked to stay in the water for approximately one hour
Suppes et al. 2016 20 - 240 (avg 72) 30 - 480 (avg 114)
Schets et al. 2011 54 (CI95 6-220) 79
DeFlorio-Barker et al. 2018 1-360 (avg 45,4-47) 0-3-year-olds: 2 - 300 (avg 56-66,7)

4-18-year-olds: 1 - 360 (avg 64-93)

The data for the tables below is from DeFlorio-Barker et al. 2018, and is the data the model uses.

Swallowed water(l/h)
Bathing time(h)

The table below shows an estimate of the age distribution of beachgoers. The data in the table is provided by Finnish Swimming Teaching and Lifesaving Federation, and is a very, very rough estimate of the age distribution. No data is currently collected of the age distribution of beachgoers.

Some arguments for this distribution:

  • 0-4-year-olds only go to the beach with 25-64-year-olds (also to a much lesser extent with the 65-79-year-olds).
  • 25-64-year-olds cover 40 years, so even though this is a group of people working and spending time at summer cottages, the total proportion is probably 0.2
  • Due to the lack of any real statistics, there is nothing to suggest differences in proportions between the age groups covering 5-64-year-olds.
  • The children and young adults between ages 5-24 might well cover 60% of the beachgoers, also depending on any possible activities on the beach, such as a tower with diving platforms.
Data updated successfully!
Beachgoers' age distribution(-)


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See also

  • Water guide
  • Quality classification of bathing waters based on an EU-directive [7] (An appendix of decree of the ministry of social affairs and health)
  • A Randomized Controlled Trial Assessing Infectious Disease Risks from Bathing in Fresh Recreational Waters in Relation to the Concentration of Escherichia coli, Intestinal Enterococci, Clostridium perfringens, and Somatic Coliphages [8]
  • Detection of Cryptosporidium, Giardia and Enterocytozoon bieneusi in surface water, including recreational areas: a one-year prospective study [9]
  • WHO: Quantitative Microbial Risk Assessment: Application for Water Safety Management


  1. Dufour et al. 2006. Water ingestion during swimming activities in a pool: a pilot study. J Water Health (2006) 4 (4): 425-430. [1]
  2. Dufour et al. 2017. Ingestion of swimming pool water by recreational swimmers. J Water Health (2017) 15 (3): 429-437. [2]
  3. Suppes et al. 2013. Assessment of swimmer behaviors on pool water ingestion. J Water Health (2013) 12 (2): 269-279. [3]
  4. Suppes et al. 2016. Cryptosporidium risk from swimming pool exposures. International Journal of Hygiene and Environmental Health 219(8):915-919 [4]
  5. Schets et al. 2011. Exposure assessment for swimmers in bathing waters and swimming pools. Water Research 45:2392-2400. [5]
  6. DeFlorio-Barker et al. 2018. Child environmental exposures to water and sand at the beach: Findings from studies of over 68,000 subjects at 12 beaches. Journal of Exposure Science and Environmental Epidemiology 28:93–100 [6]