By Noa Climor
UConn Journalism
Combined sewer overflows are unhealthy for people and the environment in a few ways. They can pour bacteria into water where people swim or go boating, and regular flooding from sewage backups can form mold inside buildings, which is linked to illness.
One of the most dangerous of the bacteria found in untreated water is E. coli. It can reach surface water through untreated wastewater, broken or leaky sewer pipes, and failing or poorly sited septic systems. If it enters a person’s body it can cause mild illness like diarrhea, but some strains can make people gravely ill with bloody diarrhea, infections, vomiting, blood poisoning, and kidney failure, the Mayo Clinic reports.
According to the Environmental Protection Agency, E. coli can enter water through various means, including leaks from wastewater treatment plants or damaged or broken pipes. This is why the state of Connecticut and many of the cities and towns routinely test swimming water for E. coli during the summer. It is measured by analyzing water samples and checking bacterial growth in laboratory analyses.
People come in contact with bacteria wading through contaminated water in their homes, if they touch their pets that have been exposed to it, or if they make direct contact with it, said Dr. Mark Mitchell, a medical doctor and environmental justice leader who co-chairs the Connecticut Equity and Environmental Justice Advisory Council. Mitchell is also a former director of health in Hartford.
The most worrisome diseases one can get in contaminated water include diarrheal diseases from E. coli, salmonella, or other pathogens, Mitchell said.
People and animals are the biggest source of harmful bacteria in water,” said Kendra Maas, a facility scientist specializing in microbial analysis at the University of Connecticut’s Center for Open Research Resources and Equipment. She explained that wastewater treatment plants use microscopic organisms to “out-compete most pathogenic bacteria, which don’t survive well in cool/oxygenated environments like wastewater treatment pools.”
But, “if sewage is untreated and released into other water, the risks are much the same as shaking hands with someone who used the bathroom and didn’t wash their hands,” she said.
Bacteria that cause human disease do so by entering the body and growing in people’s guts, Maas said. “Most bacteria that are harmful to humans aren’t harmful to the environment at large. Pathogenic bacteria tend to be very picky about where they grow. If they grow in our guts, they don’t grow well in the environment.”
Mitchell said that flooding and related health effects are worse in recent decades as rainfall has increased and storms have become more intense.
When he was an associate professor of climate change, energy, and environmental health equity at George Mason University, Mitchell created a mnemonic, HEATWAVE, to signify the health effects of climate change: Heat illness, Exacerbation of heart and lung conditions, Asthma, Traumatic injury, Water/food-borne illness, Allergies, Vector-borne disease, and Emotional stress.
“With the increase in rain, downpours, and floods, we get increased mold, and that leads to allergies and asthma,” said Mitchell. He continues to discuss the different types of bacteria and what each one causes.
“There are millions and millions of types of bacteria, but only a small number of them cause disease in humans, and a lot of those diseases can be gastrointestinal, both bacteria and viruses, things like Hepatitis B, which is commonly spread through sewage. And when you drink or are exposed to sewage, you can get those diseases. That is what we see in the sewage and combined sewer overflows, and that is where people get exposed,” said Mitchell.
Maas noted that “one of the amazing accomplishments of humans is that we have now contained our sewage, and we stopped dying of dysentery and cholera in huge numbers where we have sewers.”
“As long as you can keep the sewage contained, get it to the wastewater treatment plant, you're great,” she said.
At the plant, most of the disease-causing bacteria are removed, so the problem comes when those systems fail.
Resources
Mayo Clinic on E.coli: https://www.mayoclinic.org/diseases-conditions/e-coli/symptoms-causes/syc-20372058
Kendra Maas: https://mars.uconn.edu/about-us/
CEEJAC: https://portal.ct.gov/DEEP/Environmental-Justice/CEEJAC-Members
Dr. Mark Mitchell’s mnemonic, HEATWAVE: https://www.ncbi.nlm.nih.gov/books/NBK611582/#:~:text=HEATWAVE%20serves%20as%20a%20useful,Emotional%20stress%20(Mark%20Mitchell).
Water quality testing at Connecticut state parks: https://ctparks.com/water-quality-report
TOP IMAGE: Microscopic view of E. Coli bacteria. Photo courtesy of CDC via Unsplash.