Let’s Go Swimming!

Friday, July 17, 2009

According to the Centers for Disease Control, bacterial, viral, and parasitic organisms found in recreational water in the United States sicken thousands of people every year, and even result in deaths. We’ll speak with chemist and industrial hygienist Monona Rossol about the protozoa, amoebas and other things that love to go swimming with us. Monona is also founder and President of Arts, Crafts and Theater Safety.


Monona Rossol

Comments [33]

cynthia Newman from central N J

Hi - my son surfed all last winter at the jersey shore and picked up something - he was well one day, went surfing and the next day he was ER sick - We had 4 ER visits during his illness. He lost 3o lbs, couldn't eat, was almost bedridden and had numerous outpatient tests (colonoscopy, endoscopy, etc) - all finding nothing.It took 4 months and he slowly got well - it was pretty upsetting..I begged one of the doctors to give him cipro and he was better over night - but "it" came back when the cipro ran out...My greatest upsetment - NONE of the doctors seemed interested in articles I had from the CDC talking about water quality - runoff from roads and sewers into the ocean...the local and state health depts were useless - only help was NYNJ Surfriders - This is a wonderful group and said surfers get sick all the time and are as concerned about water quality as we are...My son was so shook up by this incident he was going to sell all his surf boards - but I told him not to give up a sport he loves and is great at - Hope I did't make a mistake by telling him to get back in the water...PS - if it was well known that the ocean water quality isn't so wonderful it would impact on tourism -so maybe that is why nobody wants to discuss it except the surfers!

Sep. 07 2009 02:27 PM
Kenny from Queens

Does a Brita need to be refrigerated?

Jul. 19 2009 11:34 AM
Riva from Brooklyn

does a heated pool present more danger in the growth of bacteria than a cooler one?

Monona Rossol responds: In general, the warmer the water, the faster the growth of microbes. I say "in general" though, because there are few species that thrive better at cooler temperatures.

Jul. 17 2009 03:58 PM
mariam from nyc

I stopped entering the swimming pool at this Manhattan Health Club because I began to see people entering into the pool without taking a shower. And if they did, their shoulders were the only portion of their body showing signs of taking "a good shower".

Shouldn't private swimming clubs be monitored by the City of New York so the attendant in the pool does not allow people without showers entering the pool?

Monona Rossol responds: I agree. The City should have some standards for employees who take the job of attendant or pool manager. It is their job to educate the users and enforce the safety rules.

Jul. 17 2009 02:58 PM
Melody from NYC

A friend and I were planning to participate in the Brooklyn Bride Swim in the East River. My friend decided not to do it due to concerns of water quality. Over 300 people plan to do this race and they do test the water before the race and will cancel if water quality is a concern (i.e. due to a recent storm). Is there anything that one should do before or after the swim? Some recommend a gamma globulin or hepatitis A shot. A listener today mentioned 50/50 drop of rubbing alcohol/vinegar in the ear - would you recommend this before or after swimming? I'd also heard of gargling with alcohol. Do you have any other suggestions? Thanks!

Monona Rossol responds: If the health department says to stay out of the water---stay out of the water. If they say it's OK, then I'd also ask them about precautions such as shots as well. I think they will not recommend this. The alcohol/vinegar is put in the ears right after you come out of the water. I've not heard of gargling with alcohol, but it couldn't hurt. Maybe taking some alcohol beverages internally might be indicated as well!!

Jul. 17 2009 02:41 PM
Jenny from NYC

mosquitos never bite me if there are other people around to bite. however, tics always gravitate to me. is there an explanation for this? Thank you.

Monona Rossol responds: There were studies that determined reasons why mosquitoes prefer to bite certain people, but I've never seen a similar study on ticks. There probably is a good reason why ticks go for you, but the ticks aren't talking.

Jul. 17 2009 01:51 PM
burtnor from Manhattan

Ms. Rossol said that the risk of HIV in swimming pools is not "the major problem," implying that it could still be some kind of problem. In fact, there has NEVER been any documented transmission of HIV from pools or drinking water fountains or from sharing eating and drinking utensils or any other casual contact. HIV transmission requires that body fluids (blood, semen, breast milk, or vaginal fluids) from an infected person enter your body. That requires sexual activity (anal, vaginal, or, in rare and special circumstances, oral fluid exchange), needle injection, or contact of infected fluids with an open cut or mucous membrane (possible between HIV patients and health care workers not wearing gloves or taking other precautions). Saliva, tears, sweat, feces, and urine cannot transmit HIV. Please do NOT leave the erroneous impression that HIV infection is possible through everyday public activities.

Monona Rossol responds: Listen again. I said people thought there might be a problem when the disease was still new to people. But I clearly stated that it could only be transmitted by exchange of body fluids.

Jul. 17 2009 01:01 PM
andrew lowry from New Jersey

I have an indoor endlesss pool. I use an ozonator and a little chlorine. No one told me there was any danger with Ozone. Is there a way to measure the concentration? Should I have a fan running? Do I need to keep the windows open - even in winter?

I measure for the chlorine content. Is there a simple test for bacteria content? I have seen it used at pools I believe.

Monona Rossol responds: You are measuring the chlorine which is important. But you should also be measuring the pH and total alkalinity. Contact your pool chemical company and ask about a more complete test kit. Once you have those measures, you can be pretty sure the environment is not conducive to growing bugs.

The ozonator is another matter. There are no nice neat regulations or tests for whether or not this is putting ozone into the air. Since it is a gas, a small amount of ventilation might be a good idea.

Jul. 17 2009 12:53 PM
Richard Stelnik from NY, NY

I swim laps about three time per week. Is there any danger of constantly breathing chlorine gas that rises above the surface of the water in a chlorinated pool? I read somewhere online that there is some gas above the water surface in chlorinated pools and it can cause problems, especially in children. But I found very little online on this. My second question is if I have a small cut, such as one from shaving, does that expose me to danger of some kind of additional infection, such as bacteria or Aids? My third question is what is the ideal temperature for a swimming pool for safety from disease/infection?

Monona Rossol responds: Great three questions.
1. Just above the water there is very little chlorine gas, but there is much more chloramine which smells like chlorine and to which many people are allergic. If there are other chemicals such as stabilizers for the chlorine in the pool, these also can be inhaled. As you would expect, asthma and related respiratory symptoms are documented in frequent swimmers.

2. Breaks in the skin such as cuts always increase the likelihood of developing infections.

3. The ideal water temperature to control disease and infection would be would be boiling hot or just above freezing!! That's not practical. So the temperature of pools is dictated by people's comfort and the chlorine and other chemicals are adjusted accordingly.

Jul. 17 2009 12:50 PM
Ron Bashford from New York, NY

Maybe what is causing the chlorine smell the caller from Chelsea experiences after a heavy rain is a reaction between the chlorine in the water and extra nitrogen in the air that is the result of lightning.

Monona Rossol responds: Lightening does some interesting things to our air. Most notably it makes ozone (O3) out of oxygen (O2). But there can be some nitrogen oxides formed as well. They don't really smell like chlorine to a chemist, but they do have an acrid chemical smell that could be mistaken for chlorine.

Jul. 17 2009 12:43 PM
Amy from Manhattan

Ms. Rossol said that washing machines are effective for getting rid of pathogens in clothes. Does that apply to washing w/cold or warm water, or does the water have to be hot?

Monona Rossol responds: Hot water is better. But even cold water with strong soap and bleach is a pretty good disinfectant.

Jul. 17 2009 12:38 PM
markBrown from

Notes on Chlorine and Mikvahs.

A mikvah does use rainwater. There is a percentage (not sure offhand of % required).

This water is mixed with "regular" water.

Then the public pool is chlorinated. So long as that rainwater does mix, it is 'kosher'.

and yes, every mikvah I've seen used by men and women, IS chlorinated in this country.

Monona Rossol responds: Thanks for clearing this up. It's appreciated.

Jul. 17 2009 12:37 PM
Mary from Westchester

In Europe, my parents have a well that collects
rainwater they use without treating. It's been in use for over 100 years and as far as I know no problems arose. Should I be concerned
when we visit?

Monona Rossol responds: Those are called cisterns, and they were used in this country for years, too. They start out with rain that doesn't have bugs, but in time, they do grow organisms. It's one reason it's not done here anymore. When you visit, drink tea and coffee made from water that has boiled!!!

Jul. 17 2009 12:37 PM
Jaimee from Brooklyn

Really? Is this program turning into a "What is under your kitchen sink that will kill you?" sort of show.
People - microbes are all over the place, they have BEEN all over the place. You live in NYC for crying out loud. Suck it up, wash yours hands and keep swimming - the people who die who from swimming in public pools is so small that this segment isn't even warranted.

Monona Rossol responds: Sorry you feel that way. Only a few people die, you are right. But thousands get sick. Simple precautions and awareness of the hazards can keep people from getting sick. I think that's worth a show. And if you had a child at the pool, I wonder if you would feel that way.

Jul. 17 2009 12:37 PM
Joel from Briarcliff, NY

How careful do I have to be about the water from a drilled well (artesian) I have at a cabin in NH? It's about 700 ft. deep.

Monona Rossol responds: I have a well below bed rock on my property in Wisconsin. Water from these sources usually has no bugs whatever. But we still had to have it chlorinated when there was a well-casing failure. Make sure your well is maintained and serviced properly, or bugs will get down there!

Jul. 17 2009 12:37 PM
Yvonne Simons from New York City

Would your guest know about the communal baths in places such as Budapest? Where people hand around for hours and almost days in warm water?

Monona Rossol responds: What an interesting question. I certainly don't know, but now that you've asked that, I'll keep my eyes open for papers from Budapest on infection control.

Jul. 17 2009 12:37 PM
David from Astoria

In response to Lea...they do chlorinate the water in mikvahs.

Monona Rossol responds: Good news. Thanks for checking this out.

Jul. 17 2009 12:35 PM
nora from Brooklyn

What about bleach?
I feel like bleach is everywhere, in just about every cleaning product. What does it do to us/ the environment?
What's the value of chlorine-free bleach?

Monona Rossol responds: There is no perfect disinfectant for water. But bleach gets a bad rap. It doesn't cause cancer. It degrades primarily to salt and other simple compounds in water treatment. Some of the complex organic chemicals it reacts with may be harmful, but they are in low concentrations.

Chlorine-free bleaches may rely on hydrogen peroxide which is unlikely to be strong enough for pool disinfection, or other compounds such as perborates, persulfates, etc., each of which has its own drawbacks.

Jul. 17 2009 12:34 PM
Evelyn from NJ

Too many people regard a shower before swimming as just getting oneself slightly wet. I swam at a very good club and I was the only one using soap in the shower.

Monona Rossol responds: I heard the same comment from another listener. This is really the fault of the pool manager who should be putting up posters, providing handouts, and educating the users.

Jul. 17 2009 12:33 PM
MS from Long Island

My issue is with folks who ignore the instructions at pools and don't shower, swim with an infection, allow their kids into the pool with diapers, etc. I wish there was a way to screen people before they go in....

Monona Rossol responds: I'm with you. I would run like a tattletale to the pool manager every time I observed this kind of behavior. If the pool manager is worth his salt, he would be very quick to speak to the people who are putting his/her clients at risk of disease. If the manager shrugs and does nothing, I'd find another place to swim.

Jul. 17 2009 12:29 PM
YourGo from Astoria

I recently got into a jacuzzi that had a heavy smell of bromine. My friend said it was OK.

i havnt noticed any side effects except it heavily tarnished all the silver jewelery of whoever got in the jacuzzi.

Was it safe to go into a stinky bromine jacuzzi?

Monona Rossol responds: I'm a chemist, and I can smell the difference between chlorine and bromine compounds. I'm going to assume you can, too, and that your observation is accurate. There are bromine bleaches used in the paper industry that could be used in a pool or Jacuzzi. Maybe this is one of these new disinfectants. But I wouldn't get into a Jacuzzi without knowing what was in the water with me no matter who said it was "OK."

Jul. 17 2009 12:27 PM
Terry Kardos from Westchester

Most pools that I have seen that require showers before entering the pool are outdoor showers; pool users stay in their bathing suits and do not use soap. This does not seem like it would help remove many microbes, or am I wrong?

Monona Rossol responds: Good thinking. The CDC suggests actual shower rooms where people can soap up. And they have a poster they recommend for pool areas and one of the suggestions is "Wash your child thoroughly (especially the rear end) with soap and water before swimming." It should be the same for adults.

Jul. 17 2009 12:25 PM
Richard Johnston from Upper West Side

Is it true that because New York's municipal water is not filtered it can carry cryptosporidium, and conversely if it were filtered would it not?

Monona Rossol responds: Almost all municipal water supplies that originate in reservoirs carry a few cryptospores. The only ones that don't are those handful that come from deep wells. And filtering won't remove cryptosporidium. But if you only drink only one or two organisms, you aren't going to notice them. It's when you get enough of the little buggers to start a convention in your gut that they will get your full attention.

Jul. 17 2009 12:25 PM
JP from Garden State from NJ

How come most people don’t get sick swimming in a pool? What are your actual chances of getting sick or is it that some people are more susceptible then others?

Monona Rossol responds: Actually getting sick depends on many factors. Your personal susceptibility to a particular organism is one of those factors. However, a high enough exposure can overwhelm the best of defenses. So it is important to know when infection control is not being practiced at a facility and to listen to the health officials when they close a beach.

The almost 5000 cases reported in 2005-2006 by the CDC probably represents a small fraction of the actual number of illnesses. Using the CDC's own estimates of failure to report, the figure is probably closer to 70,000 cases. But millions of people swim in lakes, pools, and the ocean without incident. May you be one of these lucky people forever.

Jul. 17 2009 12:24 PM
Keri from brooklyn

how safe is the mediteranian sea?

Monona Rossol responds: In general, the closer the body of sea water is to human settlement, the worse the water quality. The Mediterranean is surrounded by settlements, many of which cannot manage their waste very well. So they have the same problems we do on the Eastern seaboard with water quality on our beaches.

Jul. 17 2009 12:21 PM
JT from Long Island

What about pools that use ozone to treat the water. Is that any better or safer than chlorine?

Monona Rossol responds: Ozone is actually more toxic than chlorine. We like the smell of ozone because it smells like fresh air. And chlorine has a nasty odor. Regardless of which is used, the system in which it is used must guarantee that significant amounts don't get airborne around the pool to harm respiratory systems.

Jul. 17 2009 12:20 PM

If a clean chlorinated pool doesn't have a smell, like the guests says, why does a bottle of bleach have such a strong (pool-like) smell? I am confused.

Monona Rossol responds: It's a matter of concentration. Chemicals are detectable at different concentrations. The concentration of chlorine bleach in a pool is many magnitudes lower than the concentration in the bottle of bleach. It's below the level at which most people can detect the odor. Imagine what would happen if you swam in pure Clorox bleach!!

Jul. 17 2009 12:20 PM
Laura from Upper West Side

Off topic...picking up from previous conversation online with Ms. Rossol.

Cleaning with steam instead of chemicals. I just blasted off some crud stuck on a refrigerator shelf with my Bissell machine.

Bissell® Steam Shot™ Handheld Steamer
Item: 358-683


There are other machines, including this:

Haan Handheld Sanitizing Steam Cleaner w/ Accessories


I think Zabar's Housewares sells a hand-held steam cleaner.

For top-of-the-line machines and good advice:

Search for steam cleaners.

Many thanks.....I love these shows.

Monona Rossol responds: Thanks for the tips. I'll check those out. I love doing the shows, too!

Jul. 17 2009 12:18 PM
Mike from Brooklyn

Its rare that I am glad that I can't swim, but right now I am definitely glad.

Monona Rossol responds: Well, it's really a good thing to know how to swim. It doesn't take long to learn. Once you've learned, you don't need to keep doing it. Like riding a bike, you really don't forget how. You never know when you just may have to keep afloat in some emergency.

Jul. 17 2009 12:16 PM
Linda Griggs from Lower East Side, Manhattan

I can't go to the Pitt St. pool anymore.
If I got water in my mouth the excessive chorine (I assume) would through off my digestive tract and I'd get a yeast infection. If water got in my nose I got a sinus infection.

The last time I went there weren't many people in pool so I got. I came out and there was a LOOOGIE stuck on the stomach of swimsuit.
Chinese people expectorate in the pool and there are no signs in Chinese telling them not to.

Also, the pool water is cleaned in the morning AFTER the adult swim, BEFORE the children go in. There is no time I can go without swimming in snot and Band-Aids.

Monona Rossol responds: A LOOOGIE! Gross! Clearly there is a problem with pool management there. I'd go to and download the 12 page document called "For Aquatics Staff: Twelve Steps for Prevention of Recreational Water Illnesses." It explains clearly that part of pool management is proper education of the patrons in pool etiquette and safety. I'd attach it to an email to the people who run the Pitt Street pool. And I'd do it every week from that point on until I got an answer.

Jul. 17 2009 12:16 PM
judy from NYC

I'm getting ready to go swimming at my healthclub as i listen. Maybe I should go to the movies instead!

Monona Rossol responds: This is a good time to go to the movies. It's cool and H1N1 is not peaking yet!

Jul. 17 2009 12:16 PM
harshada wagner from uws

I love this guest! My wife is a tropical medicine specialist- she is in Africa right now- but would enjoy this interview like watching and action flick!

Monona Rossol responds: I treasure that comment. I love you back!

Jul. 17 2009 12:15 PM
Anne from NYC

How concerned should we be about pools in private health clubs? What precautions can we take?

Monona Rossol responds: The best precaution is to talk to the pool manager after you have done some homework. Go to Look for a 12-page document called "For Aquatics Staff: Twelve Steps for Prevention of Recreational Water Illnesses." This is what the manager of your pool should know. It tells you clearly what you should expect that the health club to do for you and the other patrons. If you don't get satisfactory answers from the manager, you smell strong chloramine around the pool, the posters about showering before entering the pool are not up, etc., I'd look for another "health" club. This one is unhealthy.

Jul. 17 2009 12:08 PM

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