A new study suggests that the chemicals used in wastewater treatment plants may be linked to the growth of a rare, cancer-causing bacteria.
The study, published in the journal Environmental Science & Technology, looked at how the chemicals in wastewater are disinfected and how their presence affects a variety of organisms in the environment, including fish and other animals.
The findings could provide more information on how wastewater treatment works and help scientists understand the possible links between disinfection and other human health risks, such as cancer.
The research was done in a lab with wastewater treatment plant wastewater collected from wastewater treatment facilities across the country.
“We were looking for evidence that a chemical in wastewater was affecting some organisms that live in wastewater, like bacteria and algae,” said senior author Michael T. Czeisler, a professor of biological sciences and biochemistry at the University of Southern California, in a statement.
“Our lab is one of the largest in the world and it’s been doing these kinds of studies for more than a decade.”
What we found was that the levels of a particular disinfectant in the wastewater were correlated with the growth rate of the bacteria in that wastewater, which is a big finding,” he said.
The researchers found that the concentration of chlorine in the sewage treated with chloramine was correlated with growth of the highly pathogenic bacteria Escherichia coli, which was also linked to a decrease in the growth in the animals tested.
The chemicals disinfected in wastewater include disinfectants like chloramine, hydrogen peroxide and chlorine dioxide, which have been shown to be carcinogenic and toxic.
But the researchers found a surprising correlation between disinfectants and the growth rates of a strain of algae known as Escherithiasis.
This type of algae is known to be a problem in wastewater plants, but scientists have not been able to definitively link the growth to disinfectant levels in wastewater.
The algae has been implicated in water contamination in other parts of the world, but has never been found in wastewater treated with chlorine.”
These findings may shed light on how disinfection processes work, which could be relevant for water treatment and wastewater treatment, where some of the contaminants are actually contaminants in the water, like chloramines and chloramines are very volatile,” Czezowski added.””
There are some studies that have shown that certain disinfectants can increase the growth and activity of these organisms, but the exact mechanism is not fully understood.”
“These findings may shed light on how disinfection processes work, which could be relevant for water treatment and wastewater treatment, where some of the contaminants are actually contaminants in the water, like chloramines and chloramines are very volatile,” Czezowski added.
“But it’s a very complex problem, and we need to find a better understanding of it,” said lead author and professor of microbiology at the UC Davis School of Medicine, Jennifer D. DeAngelis.
The bacteria responsible for the algae growth in wastewater is called Pseudomonas aeruginosa, which can be found in drinking water supplies, but is often difficult to isolate and identify in human specimens.
While the researchers did not test the presence of Pseudomonas in humans, they did find that the organism can be detected in wastewater samples.
“This is the first time that we have found a strain associated with wastewater disinfection, and that is really exciting,” said co-senior author Eric A. Dennison, a researcher at UC Davis.
“It’s a really exciting result, because the growth has been found before, and it may also be associated with other disinfection systems in wastewater facilities, such a chloramine disinfectant,” Dennions said.
It’s possible that the algae strain may also infect humans when they use wastewater treated at wastewater treatment sites, because it can survive in the presence and pH of wastewater, Dennisons said.
“In addition, we know that this strain can cause problems with human skin, so it could potentially be a concern,” Domenos said.
A number of chemicals that are commonly used in sewage treatment are known to increase the activity of Pseudo-Aeruginophora, a type of bacteria.
While it’s possible the algae could be growing in wastewater after treatment, the researchers caution that the findings do not prove that the organisms are growing there.
“If the algae is growing there, then there is no reason to assume that it’s going to be able to escape from the wastewater treatment facility and colonize the human body,” Czjkowski said.
“We don’t know exactly what happens when this occurs, and there are still lots of unknowns in this area.”
The researchers hope that their findings will help in future research on the effects of disinfection in wastewater systems.