treatment may also lead to the formation of new antibiotics and contribute to antibiotic resistance.
The research will be presented at the 249th National Meeting &
Exposition of the American Chemical Society, a meeting
featuring almost 11,000 presentations on a wide range of
different scientific topics. The findings suggest a re-evaluation
of how wastewater is treated is required.
"Treated wastewater is one of the major sources of
pharmaceuticals and antibiotics in the environment," says Olya
Keen, PhD. "Wastewater treatment facilities were not designed to remove these drugs. The molecules are typically very stable and do not easily get biodegraded. Instead, most just pass through the treatment facility and into the aquatic environment."
Chlorine is a disinfectant with a long history of effective water treatment. The US Environmental Protection Agency (EPA) describe it as reliable and effective against a wide spectrum of pathogenic organisms, and more cost-effective than other forms
of disinfectant.
There are also a number of disadvantages that come with using chlorine, however, such as its toxicity and the effect that it has on certain forms of matter in wastewater, potentially creating more hazardous substances.
The new study adds another disadvantage to the EPA's list,
suggesting that chlorine may be failing to eliminate
pharmaceuticals from wastewater, with potentially serious
repercussions for the environment. "Pharmaceuticals that get out into the environment can harm aquatic life, making them react slowly in the wild and disrupting their hormone systems," states Keen.
But there may be an even more dangerous consequence of
treating wastewater with chlorine. The researchers found that exposing doxycycline - a common pharmaceutical pollutant
found in wastewater - to chlorine increased the antibiotic properties of their samples.
"Surprisingly, we found that the products formed in the lab
sample were even stronger antibiotics than doxycycline, the parent and starting compound," says Keen. She adds that the compounds formed could potentially be previously unidentified antibiotics.
Reducing amount of pharmaceuticals that reach
water treatment plants is 'best solution'
Increased exposure to antibiotics in the environment, even at low levels, can result in the development of antibiotic-resistant microbes, leading to an overall weakening of the capacity of antibiotics to fight bacterial infections.
Antibiotic resistance is a major public health concern at
present. The Centers for Disease Control and Prevention (CDC) state that each year in the US, at least 2 million people develop bacterial infections from antibiotic-resistant bacteria. At least 23,000 people die each year as a result of these infections.
Keen suggests that the best solution to the problem presented in the research would be to reduce the amount of pharmaceuticals that reach treatment plants altogether. At present, the disposal of pharmaceuticals is not regulated.
By placing a greater emphasis on collecting and incinerating old
and unused pharmaceuticals, the amount that would be disposed of in drains or with regular garbage would be decreased, subsequently reducing the risk of harmful environmental exposures.
The findings also have implications for drinking water
treatment systems which also frequently use chlorine as a
disinfectant. Chlorine must remain in the piping system of
treatment facilities for several hours, Keen explains, which
affords plenty of time for the disinfectant to interact with any pharmaceuticals that may be present and potentially develop
new antibiotic compounds.
Funding for the research was provided by the University of
North Carolina at Charlotte and the National Science Foundation.
Recently, Medical News Today reported on a study that raised
concerns about whether current water treatment facilities can
adequately remove engineered nanoparticles from the water
supply.
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