Warmer temperatures and sunshine usher in those beautiful spring and summer days we all love. Many of your community residents have not been swimming since last summer and have forgotten about preventing little incidents that can close the pool.

Despite our best attempts to educate community residents about proper precautions for using the pool area, we will without a doubt have some type of contamination incident each season.

When you think about water safety, what comes to mind?

* Drowning?
* Slipping?
* Lightning?

All are very important, but did you know that germs are one of the most dangerous aspects of using public or semi-public facilities?

Recreational water illness (RWI)
RWIs are illnesses that are spread by swallowing, breathing or having contact with contaminated water from swimming pools, spas, lakes, rivers or oceans. Recreational water illnesses can cause a wide variety of symptoms, including gastrointestinal, skin, ear, respiratory, eye, neurological and wound infections. The most commonly reported RWI is diarrhea. Diarrheal illnesses can be caused by germs such as Crypto, short for Cryptosporidium, Giardia, Shigella, norovirus and E. coli.

Contamination of pools, spas and wading pools can come from several sources:

Vomit in pool water
Vomiting while swimming appears to be a common event. Often, vomiting is a result of swallowing too much water and, therefore, the vomit is probably not infectious. However, if the full contents of the stomach are vomited, the most common virus that can be in the vomit is Norovirus (also known as Norwalk-like viruses).
Respond to the vomit accident as you would respond to a formed fecal accident (see below), (this is the 2nd box) using CDC’s (Center for Disease Control) recommendations. The time and chlorine level combinations needed to kill noroviruses and Giardia are similar. Since killing Giardia is the basis of CDC’s formed fecal accident response recommendations, this protocol should be adequate for disinfecting a potentially infectious vomit accident.

Blood in pool water
Germs (e.g., Hepatitis B or HIV) found in blood are spread when infected blood or certain body fluids get into the body and bloodstream (e.g., by sharing needles and by sexual contact). CDC is not aware of any of these germs being transmitted to swimmers from a blood spill in a pool.

Q: Does chlorine kill the germs in blood?
A: Yes. These germs do not survive long when diluted into properly chlorinated pool water.
Q: Swimmers want something to be done after a blood spill. Should the pool be closed for a short period of time?
A: There is no public health reason to recommend closing the pool after a blood spill. However, some pool staff choose to do so temporarily to satisfy patrons.

Free chlorine at neutral pH kills most bacteria such as E. coli in less than a minute if the free chlorine is maintained at proper disinfection levels throughout the pool. However, a few germs are moderately (Giardia, Hepatitis A) to highly (Cryptosporidium) chlorine-resistant. The table below shows the approximate disinfection times for these germs in chlorinated water.

Agent                         Disinfectant Times for Fecal Contaminants in Chlorinated Water*
E. coli 0157:H7
Bacterium                                     < < 1 minute
Hepatitis A
Virus                                           Approximately 16 minutes
Giardia
Parasite                                       Approximately 45 minutes
Cryptosporidium
Parasite                                       Approximately 9,600 minutes (6.7 days)

1 mg/L (1ppm) free chlorine at pH 7.5 and 25o C (77o F)

These disinfectant times are only for pools that do not use chlorine stabilizers such as cyanuric acid. Disinfection times would be expected to be longer in the presence of a chlorine stabilizer.

Rodent contamination including mice, rats, possum, squirrels, rabbits
Respond to the rodent contamination as you would respond to a formed fecal accident (see below), using CDC’s recommendations. The time and chlorine level combinations needed to kill noroviruses and Giardia are similar.

Formed stool fecal accidents
In February of 2008, the CDC released new Giardia Inactivation time recommendations for formed stool contamination. The new minimum closure times are listed in the following table.

Chlorine Level at time of incident (ppm)   Disinfectant Times for Fecal Contaminants in Chlorinated Water*

1.0                                                                45 minutes
2.0                                                                25 minutes
3.0                                                                19 minutes

*These closure times are based on 99.9% inactivation of Giardia cysts by chlorine at pH 7.5 @ 77 degrees F. The closure times were derived by the United States EPA disinfection profiling and benchmarking guidance manual. These closure times do not take into account “dead spots” or other causes of pool water circulation.

The recommended procedure for a formed stool contamination event is as follows:

* Immediately direct everyone to leave the pool.
* Remove the contamination without breaking it apart.
* Dispose of the contaminated material in an appropriate receptacle (toilet).
* Sanitize the net used to remove the contamination. (Pool operator should use rubber gloves.)
* Test the current chlorine level and raise to 3 ppm.
* Test the pH and adjust to 7.2 to 7.4.
* Check the filtration systems (pumps and filters) to insure proper operation.
* Keep the pool closed and filtration systems on for a minimum of 25 minutes.
* Retest the pool water (safe to reenter if free chlorine and pH are within limits).
* Backwash the filter.
* Log the incident in the pool log book.
* Allow swimmers back into the pool.

Loose or diarrheal fecal accidents
This is the most difficult type of contamination to control. The CDC has also updated the minimum recommended closure times per the following table.

Chlorine level at time of incident (ppm)    Disinfectant times for fecal (loose ) contaminants in chlorinated water*

1.0                                                            255 hours or 10.6 days
10.0                                                          25.5 hours or one day
20.0                                                          12.75 hours or overnight

*Raising the free chlorine level to 20 ppm may require an additional 12-24 hours for levels to return to a high normal range (FC of 3-5 ppm for pools/waders and FC of 5-10 for spa).

The body of water may need to be partially drained to reduce the Free Chlorine (FC) level to less than 20ppm if this method is selected.

These closure times are based on 99.9% inactivation of Giardia cysts by chlorine at pH 7.5 @ 77 degrees F. The closure times were derived by the United States EPA disinfection profiling and benchmarking guidance manual. These closure times do not take into account “dead spots” or other causes of pool water circulation.

The recommended procedure for a loose or diarrheal fecal contamination event is as follows:

* Immediately direct everyone to leave the pool.
* Remove as much of the fecal material as possible.
* Do not vacuum stool or diarrheal material from the pool.
* Dispose of the contaminated material in an appropriate receptacle (toilet).
* Sanitize the net used to remove the contamination. (Pool operator should use rubber gloves.)
* Test the current chlorine level and raise to a minimum of 10 ppm (20 ppm is recommended for smaller bodies of water).
* Test the pH and adjust to 7.2 to 7.4.
* Check the filtration systems (pumps and filters) to insure proper operation.
* Keep the pool closed and filtration systems on for a minimum of 24 hours.
* Retest the pool water (safe to reenter if free chlorine and pH are within limits).
* Backwash the filter completely (if sand filtration), or disassemble and disinfect each component (D.E. and cartridge filters).
* Log the incident in the pool log book.
* Allow swimmers back into the pool.

Plan of action for your community
This is the time of year to educate and remind residents of their role in preventing contamination events. The following are some simple recommendations:

* Require all infants and small children to wear waterproof diapers designed specifically for swimming and wading pools.
* Prohibit swimming for persons with open sores or cuts.
* Limit or prohibit consumption of alcoholic beverages.
* Request that persons with cold, flu or other symptoms confine their activities to the area around the pool and refrain from entering the pool or spa water.
* Require that all swimmers shower before entering the pool/spa.
* When calling your pool service to handle a contamination incident, please ask residents to provide as much detail as possible about the event.

Following these simple rules and recommendations can reduce the risk of recreational water illnesses and insure your community has a safe and enjoyable swimming season.

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Author : Fred Ross
Company : Deckside Pool Service
Fred Ross is the president of Deckside Pool Service.

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