It attacks the disease-causing microorganisms that may be hanging out in the water and prepares a pool for swimming. However, that is not all the chemical does. Chlorine may be a long-standing disinfection success story, but the reality is that the very process that delivers such good results has an irritating downside: byproducts that are harmful to the skin and the rest of your body.
When chlorine contacts water, a reaction occurs that forms hypochlorous acid. During this process of chlorination, the hypochlorous acid breaks down the cellular components of pathogens to eliminate them. That process is what is supposed to happen when a pool is treated with chlorine. Chloramines not only smell awful, but they also reduce the potency of the free chlorine remaining in the pool, which in turn, hinders the chlorines ability to further disinfect the water.
This reaction makes it easier for pathogens to survive in the pool and contaminate any swimmers. In addition to potentially causing illness, chloramines are also among the components that cause harm and irritation to the skin. Chlorine itself as well as its byproducts can have a dramatic impact on the outer layer of your skin. Some of the most common issues associated with chlorine exposure include:. While avoiding chlorinated pools and hot tubs is the easiest preventative measure in theory, it may not be quite as easy in practice if you generally rely on a traditionally chlorinated facility.
The distribution of the three types of chloroamines is a function of pH 5. Chloroamines are combined chlorine residuals and the concentration of chloroamine in the water can easily be calculated using;. As there are simple tests using small tablets that dissolve in the pool water producing colours - the colours relate to concentration for the amounts of free chlorine and total chlorine in the water the combined chlorine concentration can be calculated by subtracting the amount of free Cl from the total amount of Cl.
Dichloroamine has a disagreeable taste and odour - the characteristic 'chlorine' smell of swimming pools. In order to break down chloroamines more chlorine must be added. The UV radiation breaks nitrogen-chlorine bonds in some DBPs, producing radicals that can help form even nastier by-products such as cyanogen chloride, a toxic agent that can attack respiratory organs Environ.
Overall, the radiation improves the chemistry and microbiology of swimming pools, but there are certain chemicals that you still need to worry about, he adds. And those chemicals have a chance to accumulate because pools generally recirculate their water. The only water that regularly gets replaced in pools is the water lost to evaporation and the water used to flush out the sand filter in the recirculation system, Zwiener explains.
The analogous voluntary standard in the U. That means it takes about days for much of the water in a pool to be replaced— days during which DBPs are accumulating. But how do those DBPs form in the first place? But most of them are brought along for the ride on or in people using the pool. Some DBP precursors are on the skin: Think hair, skin cells, dirt, or personal care products. Others are in sweat. But the biggest contributor to DBPs in pools is urine.
Some of that is released accidentally or without the person realizing. But for elite swimmers, peeing in the pool is an accepted part of the culture. Eldridge, the Masters swimmer, confirms that peeing in pools is commonplace in elite competitive swimming. Practices can last for hours, Eldridge says, and swimmers chug water during stops between intervals.
Swimmers rarely leave the pool during that time. Olympic swimmers Michael Phelps and Ryan Lochte have both been captured on video admitting to peeing in the pool and seeing nothing wrong with it. A quick YouTube search turns up multiple such videos highlighting their cavalier attitudes. That urine contains a lot of urea, a nitrogen-laden molecule that reacts with chlorine in pool water to form a DBP called trichloramine.
This resultant chemical—not the chlorine itself—helps give indoor pools their distinctive odor and has been associated with respiratory symptoms. The second category is sweat. The amount that people sweat in pools depends on both the water temperature and their level of activity. In one study, Keuten tested the effect of water temperature on sweating by measuring the sweat production of people wearing water-filled rain suits and exercising on a submerged cross-trainer Water Res.
The concept is similar to the activity known as aquaspinning, in which people ride a stationary bicycle submerged in water. In another experiment in the same study, Keuten studied sweat production in swimmers. One group was composed of recreational swimmers exercising at light to moderate levels. In the other group, triathletes swam vigorously. The amount of sweating was measured by weighing the swimmers before and after swimming.
The third major category is urine. This one is the hardest to pin down because people can be cagey when asked about it. In another study, Keuten provided a shower cabin for people at an outdoor pool to use. People coming straight from home showered in the cabin for two or five minutes, and Keuten collected and analyzed the water that rinsed off participants and drained from the cabin floor Water Res.
Later in the day, he asked people lying around the pool to shower again. Participants had been lying around the pool or on the grass, where they had been sweating and picking up dirt. Outdoor pools really should focus on the personal hygiene of swimmers, not just the first time they jump in, but every time they jump in. Complicating matters is the fact that the level of chlorine needed throughout the day can fluctuate.
There are literally hundreds of—maybe even more—different DBPs in swimming pools. The most abundant of these are trihalomethanes, such as trichloromethane, more commonly known as chloroform; haloacetic acids; and chloramines, especially trichloramine.
Haloacetic acids are not volatile, but the rest of the DBPs can be found in the air around swimming pools. Blatchley uses a method called membrane-introduction mass spectrometry MIMS to measure volatile DBPs from the air around swimming pools and at the air-water interface.
In MIMS, the compounds undergo a process called pervaporation that allows them to diffuse through the membrane and be swept straight into the mass spectrometer. MIMS can detect compounds only at microgram-per-liter or higher concentrations, so anything it detects is at a pretty high concentration compared with other DBPs. Blatchley points to the heavy corrosion of stainless steel and other metals around pools. Volatile DBPs such as trichloramine are the compounds most likely to contribute to respiratory problems in swimmers—if those problems are indeed caused by chemical exposure.
Better instruments are allowing scientists to see more and more of those other DBPs. Susan D. Richardson , a water chemistry expert at the University of South Carolina, uses two-dimensional gas chromatography coupled with quadrupole time-of-flight mass spectrometry to identify those DBPs. In one case of water from a brominated pool, the researchers saw more than 19, resolved peaks in their chromatogram. But Richardson and her colleagues can identify only a fraction of the compounds represented by those peaks.
She did, however, identify previously unknown DBPs, including two new brominated imidazoles and other nitrogen-containing DBPs. Some of the DBPs causing the multitude of chromatogram peaks may be never-before-seen contaminants from new drugs that are peed out by swimmers or new personal care products that rinse off their skin. The question was where they were coming from. The concentrations in the pool were significantly higher than those in either the input tap water or urine from swimmers.
That meant halobenzoquinones must be coming from somewhere else. When Li and her group did laboratory disinfection studies of several widely available lotions and sunscreens, they found that high levels of halobenzoquinones would accumulate, making those personal care products the likely culprits. The benzoquinones likely come from phenyl-containing molecules in the personal care products. Benzoquinone is a known carcinogen. Toxicity data collected from cell-based assays show that halobenzoquinones are more damaging than benzoquinones, Li says.
They produce a much greater amount of reactive oxygen species in cells, resulting in damage to DNA and proteins, she says. But the nature of the association is harder to determine. Did those swimmers develop asthma because they swim, or do they swim because they have asthma? One of the complicating factors is that doctors recommend swimming as a sport suitable for people with asthma. And the effects on children are even less clear. Belgian researchers have shown in a series of studies that swimming as a young child is related to increases in respiratory symptoms and asthma for example, Environ.
Health Perspect.
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