WESTPORT — Health officials in Westport, Darien and Branford recently completed a study focusing on the source of E. coli and other bacteria in water streams, using a new method called DNA source tracking, also known as microbial source tracking.
One of the areas of study was Sasco Brook in Westport under the guidance of Darien Health Director David Knauf, Westport-Weston Health Director Mark Cooper and Michael Pascucilla, health director of the East Shore District that includes Branford, East Haven and North Branford.
Researchers are interested in tracking the source of the bacteria, which is present in fecal matter. Although they weren’t able to determine the exact source of the contamination, they said their work was still relevant in drawing attention to the issue and the limitations of current research methods.
“DNA source tracking could be a tool to provide that needed information to public health officials to make scientifically supported decisions and public advisories,” the health directors said in a joint statement.
Cooper said the project started around 2009 with the Westport-Weston Health District and the Sasco Brook Pollution Abatement Committee, as part of the Sasco Brook Watershed Based Plan.
Cooper said the plan called for the microbial source tracking analysis because he questioned the “assumption that most of the pollution is from leaky septic systems.”
He said that the modeling used for computer-based watershed planning doesn’t “provide definitive results nor sufficient confidence to gain citizen support or the allocation of municipal funds for targeted best management practices for pollution reduction.”
“As much as computer modeling can be a valuable tool to estimate the relative contribution of different sources of pollution, every computer model is limited by the assumptions used to develop the estimate,” he added.
After reading several studies, Cooper said he “was convinced that wild and domestic animal contributions to the bacterial loading in Sasco Brook Watershed was being discounted.”
A grant application was submitted in March 2011 to fund the study, but it wasn’t approved, Cooper said. The grant was then reformatted for three watersheds — Sasco Brook, the lower Farm River and Goodwives River.
He said this was because the other health directors had similar concerns about their nearby streams.
He added, “It should also be noted that the East Shore District Health Department, in partnership with Yale University conducted the first known Connecticut DNA study using this non-approved, EPA experimental technology in 2010 on the East Haven/Branford’s town boundaries in Farm River.”
In their joint statement, the health directors said they were curious to know if the bacteria in the streams was coming from humans, animals, birds or somewhere else. They felt the DNA source tracking could help pinpoint ‘actual contributors’ to the high bacteria counts.
The December 2022 edition of the Journal of Environmental Health published the study, in which the researchers collected samples once a month near the end of each watershed and analyzed them for E. coli, which is a traditional indicator for fecal matter, as well as other genetic markers.
These markers can identify sources of contamination like domestic animals, humans and wildlife.
The health directors explained the concerns with fecal matter in the waterways, saying it “is related to the risk it would pose to people swimming in those waters, especially if the source is human. If the source is found to be human, it poses a significant human health hazard, as well as to the shellfishing industry multi-million-dollar economy in Connecticut and beyond our state boundaries.”
The conclusion said that the study confirmed past findings that the three watersheds “were consistently affected by elevated levels of fecal contamination after a rainfall event.”
However, the researchers were not able to make a “conclusive determination” of the actual sources with their tools, despite finding elevated E. coli levels in each of the three watersheds.
“When it rains,” the health directors said, “a significant portion of that rainfall runs across the surface of the ground, across streets, parking lots, farm fields into brooks and streams — this is commonly referred to as a ‘first flush.’ Anything on the ground, including domestic animal waste, can wash away.”
They also said that rainfall can affect sewer systems, where human sewage overflows into it. The researchers noted that the levels of indicator organisms, like E. coli, that show the presence of fecal matter also seemed to conflict, making it important to evaluate the accuracy of these types of indicators and to develop “other methodologies for assessing actual sources of bacterial contamination.”
The health directors said that the study was important because “understanding the source of bacteria would help assess the risk the bacteria found in the waters pose to human health, and if we know the sources of bacteria, efforts to reduce the bacteria load can be undertaken if there is a risk to human health.”
“Specifically, our end goal as local public health officials is to identify and remediate the root cause of water quality contamination as efficiently and effectively as possible,” they also said.
The health directors said they were disappointed that they didn’t have more definitive results.
“However it did highlight what we need to do in the future to achieve better outcomes and obtain more meaningful information,” they said. “In fact, the point of epidemiological research is to identify the distribution of disease, factors underlying their sources and the methods of control, and it’s a process that requires trial and error.”
They said that their published research in the journal “has fostered a national/international conversation to better refine the MST methodology as a public health tool.”
The health directors said that unless they can receive additional funding, this is the end of their research.
“Anyone responsible for ensuring the health of people utilizing our beaches, fresh and salt water, including the consumption of raw shellfish should be aware of this initiative,” they said. “Perhaps interest could be generated to further foster the conversation to enable funding to expand this water quality pioneering research among all stakeholders — governmental, businesses and community alike. In short, Long Island Sound is a Connecticut (and New York) gem, and we are quite lucky to have this beautiful estuary in our backyard.”
“Frankly, it’s all hands-on deck to protect this fragile natural resource for future generations,” they said.
kayla.mutchler@hearstmediact.com
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