Urine + chlorine may equal health risks
at pools
Lian, L, E Yue, J Li,
ER Blatchley. 2014. Volatile
disinfection byproducts resulting from chlorination of uric acid: Implications
for swimming pools. Environmental Science & Techology. Synopsis
by EHN Staff
Peeing in swimming
pools may be hazardous to your health. That’s the message from scientists who
have found that compounds in urine mix with chlorine to form chemicals that
have been linked to respiratory effects in swimmers.
Peeing in swimming
pools may be hazardous to your health. That’s the message from scientists who
have found that compounds in urine mix with chlorine to form chemicals that
have been linked to respiratory effects in swimmers.
Researchers in recent
years have been trying to determine whether breathing disinfection byproducts
in the air at indoor pools can lead to asthma or other respiratory problems.
In a series of
laboratory experiments, the scientists combined water collected from swimming
pools in China with mixtures meant to mimic the chemical composition of sweat
and urine. Chlorine, used to disinfect pools, reacts with a number of chemicals
found in human sweat and urine.
Uric acid, found in
urine, accounted for 24 to 68 percent (depending on temperature, water pH and
chlorine condition) of the byproduct cyanogen chloride in the pool water
samples. Cyanogen chloride can affect multiple organs, including the lungs,
heart, and central nervous system via inhalation.
This is the first time
uric acid has been identified as a major cyanogen chloride precursor in
swimming pools, the researchers noted. Roughly 93 percent of uric acid in
swimming pools comes from human urine. Sweat also contributes a small amount.
Uric acid also
accounted for about 3 to 4 percent of another byproduct, trichloramine, in pool
water. Previous studies have found that urea, another urine compound, converts
readily to trichloramine.
Exposure to
trichloramine at pools has been linked to reduced
lung function in adult
swimmers, and itchy
eyes, runny nose and voice loss in lifeguards.
Swimming pools also
might affect the airways of competitive swimmers. Bronchial biopsies of
swimmers showed airway changes, including Inflammation, similar to those
seen in people with mild asthma, although the changes weren’t associated with
asthma symptoms.
Some studies have
suggested a
connection between
childhood asthma and swimming in indoor pools, while others have found no
connection.
The average swimmer
introduces the equivalent of up to two shot glasses of urine into a pool each
time he or she takes a dip, according to previous research.
