By Jim Cowan

Clark County Health Dept. Health Environmentalist

Memorial Day Weekend, the unofficial beginning of summer, is fast approaching, bringing with it the start of pool season. And in these hot months, pools not only offer enjoyable ways to cool off but also great health benefits because of increased physical activity in the water.

However, there are also some health concerns swimmers need to be aware of as they enjoy the water.  

Specifically, pools provide an easy way to spread disease causing germs to anyone who enters them. 

Pool operators must maintain adequate levels of sanitizing chemicals in the water to prevent this transmission of illnesses.

The greatest concerns are with those diseases that are the result of a fecal-oral connection when contaminated pool water is inadvertently swallowed.  These include diseases caused by Cryptosporidium, Giardia, E. coli and Norovirus.  

Because the symptoms for these are all similar, and typically include diarrhea, nausea, stomach cramps and vomiting, many people will mistakenly assume they have food poisoning.  Few will ever realize they may be victims to poor pool management.

To properly sanitize the water in which we swim, Kentucky commercial pool operators are required to maintain a minimum of 1.0 parts per million (ppm) concentration of free chlorine or 2.0 ppm for free bromine.  

Even at that, germs are not killed instantaneously.

The time it takes to kill or inactivate germs in minimally chlorinated water varies, depending upon the disease agent:

— E. coli 0157:H7 takes less than a minute

— Hepatitis A virus takes about 16 minutes

— Giardia takes about 45 minutes

— Cryptosporidium takes more than 10 days

If there is a fecal event at a pool, the recommendation is to close the pool and superchlorinate the water to at least 10.0 ppm.  

By increasing the chlorine concentration by a factor of 10, the time required to kill the germs is reduced by a factor of 10. 

So instead of closing the pool for 10 days waiting to kill the Crypto parasite, the pool needs to be closed for only one day.

But chlorine and bromine are not the only chemical considerations to which operators need to pay attention.  

A measurement designated by pH indicates how acidic or basic the water is.  A pH of 7.0 indicates a neutral (not acidic or basic) substance, such as pure water.  Battery acid, with a pH around 0.0, and lye (found in liquid drain cleaners), with a pH around 14.0, are both extremely dangerous.

The germ-killing ability of free chlorine is affected by the water’s pH; the acceptable range being 7.2 to 7.8.  

At a pH of 7.8, the free chlorine can only kill half as many germs as it can at 7.2.  Above 7.8, not only is the sanitizing ability poor, but the water will greatly irritate the swimmers’ eyes.  (Some think there is too much chlorine, when it is actually the pH that is too high.) 

Below a pH of 7.2, the metal components of the circulation system will start to corrode (e.g. rust).

Because the available free chlorine and pH in a pool can change rapidly because of bather load and sun exposure, Kentucky commercial pool operators must test and record the water chemical levels at least three times each day.  In so doing, they can make adjustments to maintain the appropriate sanitizing levels of the chemicals in a timely manner.

In order to enjoy a healthy and safe swimming season, the Centers for Disease Control and Prevention encourage families to use the following checklist:

— Check the pool’s latest inspection results.

— Make sure the drain at the bottom of the deep end is clearly visible.

— Check that the drain covers at the bottom appear to be secured and in good repair.

— Check to make sure the pool chemicals are within appropriate ranges: Free Cl 1.0 ppm to 2.5 ppm. or Free Br 2.0 ppm to 5.0 ppm and pH 7.2 to 7.8

— Check for a lifeguard: If on duty, a lifeguard should be focused on the swimmers and not distracted.

If no lifeguard is on duty, a “No Lifeguard on Duty” sign should be posted.

If no lifeguard is on duty, check to see where safety equipment, such as a ring buoy or shepherd’s hook, is available.

— Make sure no chemicals are out in the open.

Parents should also follow healthy swimming practices with their children by observing the following tips:

— Don’t swim or let children swim when sick with diarrhea.

— Don’t swallow the water.

— Take kids on bathroom breaks every hour.

— Check diapers, and change them in a bathroom or diaper-changing area, not poolside, to keep germs away from the pool.

— Shower before you get in the water.  Rinsing off in the shower for just one minute helps get rid of any germs that might be on your body.

Other health considerations include sun safety, since the ultraviolet (UV) radiation can damage your skin within 15 minutes.  Protection can be achieved by seeking shade, wearing hats, long-sleeved shirts and long pants, sunglasses and using a broad-spectrum sunscreen with at least SPF 15 before going out.

Of course, any swimming safety issues must include drowning prevention.  Tips from the CDC include ensuring everyone knows the basics of swimming (i.e. floating, moving through the water) and CPR.  

Also, children must be watched constantly by a non-distracted adult any time they are near a body of water (including the bathtub).  

And though it is a requirement for commercial facilities, all pools, residential included, should have a four-sided isolation fence with a self-closing and self-latching gate.

For more information, contact Jim Cowan at the Clark County Health Department evironmental office by email at jamesm.cowan@ky.gov.