This summer, researchers from the University of Connecticut’s Department of Marine Sciences partnered with local health districts and Save the Sound to explore an untraditional method of monitoring water quality at Green Harbor Beach in New London and Rocky Neck State Park in East Lyme.
The project is funded by a 2022 Long Island Sound Study Research Program grant totaling over $450,000. From Memorial Day to Labor Day, project partners will take weekly samples at both beaches. The sites regularly experience pathogen-related advisories and closures and receive C and D grades in the Long Island Sound Beach Report published by Save the Sound each year.
“They have a history of exceedances of the pathogen indicator bacteria criterion for safe swimming,” said Peter Linderoth, Director of Water Quality at Save the Sound. “And we don’t always know the source of the bacteria. So, this project is going to be telling in helping do some source tracking. Whether it’s sewage from people or goose poop, it needs to be managed.”
Green Harbor Beach is located within an Environmental Justice community, as identified by the state’s EJ Mapping Tool. These communities are marked by their experience of “disproportionate impacts of pollution” and “chronic health conditions and social stressors.”
The project aims to address these challenges by enabling more rapid beach advisories and necessary closures. This could not only protect public health more effectively but also provide researchers with insights into the sources of the high bacteria levels. Current culture-based monitoring methods, used nationwide, often take over 24 hours to yield results, which means advisories are issued a day after the samples are collected—offering little protection to those who were exposed to the water the previous day.
“The research gets to the heart of that limitation in the current system,” said Linderoth. “It’s much more protective of human health.”
The new analysis method uses quantitative polymerase chain reaction, or qPCR, to get results by increasing the amount of DNA from indicator bacteria, specifically the tuf gene, which is a constituent of the bacterial genome. Unlike the double-stranded helix humans share, bacterial DNA is a singular circular coiled strand.
“With each cycle as the gene is amplified, the intensity of fluorescence increases, and it registers a “hit” if the fluorescence reaches a certain intensity,” said Glass.
The analysis can also detect DNA marker HF183, which is specific to human Bacteroides, or anaerobic bacteria. This capability is important for detecting potential raw sewage exposure in the water. The EPA started exploring the use of molecular genetics for beach testing back in 2012. In recent years, coastal counties nationwide have explored the feasibility of qPCR technology at beaches with historically high exceedances.
The thermocycler works by copying bacterial DNA in cycles. If there are many genes and a lot of genetic material, the PCR machine will need fewer cycles to reach the detection limit, which can be range from 12-35 cycles. The fewer the number of amplifying cycles, the higher the levels of the indicator bacteria. In addition to the PCR equipment being highly portable, which allows for more timely and efficient sampling, it can also generate results in under an hour.
“It all depends on if you’re taking the sample at high or low tide, or anywhere in between,” said Luke Glass, a second-year PhD student at UCONN working under one of the project’s principal investigators Michael Whitney, a marine sciences professor. “You sometimes don’t get the variation that could happen on a tidal cycle. But that’s why we’re getting that data. We can input these parameters and you can see what is the change of bacteria over time with a much higher temporal resolution.”
Identifying the presence and level of bacteria and pathogens in the water is just one element of the project. Tying environmental conditions of rainfall, tides, winds, and temperatures to bacteria levels will support source tracking efforts and the possibility of forecasting closures in the future. Once data gathering efforts are completed, project researchers will determine if there is potential to use the method long-term for beach closures.
Project partners also plan to engage with the communities surrounding Green Harbor and Rocky Neck beaches through public meetings, providing an opportunity for residents to participate in conversations about the quality of the water.
“We want to be protecting and restoring water quality across the Sound for everybody that wants to enjoy or use the water in these communities,” said Linderoth. “It’s valuable to connect the ins and outs of the water and how it’s evaluated in terms of health for people to interact with it.”
You can find more information about safe swimming at Connecticut state beaches here. Photo by Luke Glass