Is recreation along the Hudson still safe? Assessing the risks from the COVID-19 virus
April 10, 2020
Riverkeeper Team
In a series of posts, Riverkeeper compiles the available information – and unanswered questions – on the possible risks the COVID-19 virus may pose via sewage-contaminated water.
New York is at the center of the COVID-19 pandemic, and it’s urgent that we stay focused on preventing transmission through the known routes – interpersonal contact and contact with surfaces contaminated with the COVID-19 virus.
At the same time, Riverkeeper is actively studying the available information on the risks the COVID-19 virus may pose to individuals or communities via sewage-contaminated water. Riverkeeper recognizes that our organization is not expert in epidemiology or infectious diseases. Click the links below to explore this topic further.
Q. Are people who enjoy recreation in or on the Hudson River or its tributaries at risk of exposure to the COVID-19 virus?
A. Based on available evidence, Riverkeeper recommends that people avoid contact with water that may be affected by sewage that is untreated or which has been treated without disinfection. If people do come into contact with river or tributary water, Riverkeeper recommends taking reasonable precautions, such as avoiding ingestion of water and full immersion in water, avoiding hand-to-face contact during recreation, and thoroughly washing after contact.
There is no data yet available about whether the COVID-19 virus can be detected in the Hudson River or its tributaries, or if it is viable at levels that present an infectious risk to recreational users. We know much more about other pathogens associated with sewage. If sewage proves to be an important vector for COVID-19, then we would expect that the Hudson River and its watershed will be affected, as New York City is the center of the global pandemic.
The Hudson River and several of its tributaries are significantly affected by sewage. On a typical day, 349 million gallons of treated wastewater are discharged to the Hudson River or its tributaries upstream of New York City, and another 1.3 billion is discharged by New York City’s 14 treatment plants into the Hudson, East River and other waters. Treatment of this sewage is critical for protecting public health.
The fact is, not all sewage is treated adequately – or at all. Millions of gallons are discharged from combined sewer systems when it rains, leaks and overflows from our aging infrastructure are common, and not all treatment plants are required to disinfect effluent at all times of year (and some aren’t required to do so at any time of year).
Since 2006, Riverkeeper has gathered water quality data from the Hudson River Estuary in collaboration with Columbia University’s Lamont-Doherty Earth Observatory and CUNY Queens College, and from many of the Hudson River’s tributaries with a wide range of partners and community scientists. Our analysis of these data reveal patterns that illuminate where and when this wastewater is effectively treated, and where it is not.
We measure a group of bacteria called enterococci (Entero). While Entero are not likely to make you ill, they are known as fecal indicator bacteria. The purpose of measuring them is to define where pathogens associated with sewage or other fecal contamination may be present in water. Pathogens may include harmful bacteria, viruses or other disease-causing microbes. Thus, while we have no data on COVID-19 in water, we have learned important facts about where and when pathogens associated with sewage are more likely to be a risk.
Our data show that most of the Hudson River is safe for recreation most of the time. The data also give us important insights into the risks associated with the potential to be exposed to pathogens in water:
• Higher risk near many communities with combined sewer overflows (CSOs), particularly after rain. Communities with CSOs include New York City, the Capital District, Yonkers, Newburgh, Poughkeepsie, Kingston, Hudson, Catskill, West Point, Glens Falls, Fort Edward, Hudson Falls, Utica, Little Falls and Amsterdam.
• Higher risk, particularly after rain, near Hudson River shorelines, as compared to the river farther from the shoreline.
• Higher risk, particularly after rain, in tidal tributaries of the Hudson River, including the Rondout Creek, which is also affected by combined sewer overflows from Kingston.
• Wide variation in contamination levels in Hudson River tributaries, based on sampling of many but not all Hudson River tributaries, over different lengths of time. Some tributaries show persistently higher risk (including Wallkill River, Saw Mill River, Sparkill Creek, Bronx River and Pocantico River). Others show frequent but less extreme or more variable risks (including Rondout Creek and Esopus Creek). Others show generally lower risks (including Roeliff Jansen Kill, Saw Kill, Catskill Creek). All tributaries show variability from site to site along their lengths, and all show higher levels of contamination after rain.
Data on the Hudson River and its tributaries are summarized in these reports, which can provide information to guide people’s decisions about recreation in or on the river where and when there is least likelihood of risk.
Published scientific research we have contributed to has also demonstrated that:
• contaminated sediment can be an important source of fecal indicator bacteria at shorelines;
• contaminated water can aerosolize and affect air quality near highly polluted water; and
• other infectious viruses can be detected in parts of our watershed.
Research has also identified some relevant uncertainties. Does contaminated sediment harbor pathogens, like viruses, or only fecal indicator bacteria? Where birds are an important source of fecal contamination, relative to humans, as is the case in at least some Hudson River tributaries, what is the relative risk to human health?
Based on this body of evidence about the presence of pathogens from sewage in the Hudson River and its tributaries, and the potential for COVID-19 to be present in water contaminated by sewage, Riverkeeper recommends that people avoid contact with water that may be contaminated by untreated sewage or sewage has been treated without disinfection. We are not alone in making this kind of recommendation. Chicago, for instance, has warned residents of the potential risk of contact with waters affected by that city’s combined sewer overflows.
The bottom line: The Hudson River and some of its tributaries are affected by sewage contamination, including sewage that is untreated or treated without disinfection. While any potential exposure risk is likely to be substantially lower than for other modes of transmission (such as interpersonal contact), the available evidence suggests a potential risk of exposure to COVID-19 virus in sewage-contaminated water. Riverkeeper recommends people avoid contact with water that may be affected by untreated sewage or sewage that has been treated without disinfection.
More:
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Water quality monitoring
Riverkeeper is the go-to source for information about the quality of the water along the Hudson River and its tributaries
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