Pathogens

The primary measures of success are to achieve a five-year rolling average of 85 percent of beaches graded B- and above based on beach data from Sound Health Explorer (starting from a baseline of 75.5 percent from 2003-2023); to complete 11,500 onsite wastewater treatment system (OWTS) replacements, upgrades, and/or removals; and increase the number of samples collected by 10 percent and increase the spatial coverage of monitoring relative to a 2023 baseline (983 samples collected at 93 sites).

Status

The five-year rolling average of beaches graded B- or above from Save the Sound’s Sound Health Explorer, pathogen detection has declined since 2007. While the overall average regional beach grades vary from year to year, recent data is relatively stable since 2019. However, grades declined from 2023 to 2024 across Connecticut and in western Suffolk County but were otherwise constant for other New York  beaches. Causes include aging wastewater and stormwater infrastructure, improperly functioning OWTS, and uncontrolled/untreated runoff from pet and wildlife waste. Furthermore, other environmental influences can impact the concentration of pathogens – increased temperatures can increase bacterial growth and intense rain events flush more pathogenic bacteria into the Sound.

Polluted runoff from developed land, leaking wastewater infrastructure, and improperly functioning OWTS can release pathogens into water bodies causing closure of beaches and restrictions on shellfish harvesting areas. The term “pathogens” is used to describe disease-causing bacteria, viruses and other micro-organisms. The Partnership monitors water for the presence of pathogens by testing for indicator bacteria. The presence of indicator bacteria at certain levels is used to presume the presence of pathogens.

This objective aims to reduce pathogen contamination from wastewater and stormwater infrastructure and onsite treatment. To track progress, the five-year rolling average of beaches graded B- and above based on beach data from Sound Health Explorer will be monitored, with a goal of 85 percent of beaches graded B- or above. The number of OWTS replaced will also be tracked to monitor progress. Another aspect of this objective aims to enhance our understanding and to better inform the management of pathogen contamination through increased monitoring. Number of samples collected, and temporal and geographic distribution relative to a 2023 baseline will be analyzed to track progress of this objective. The 2023 baseline is 983 samples collected at 93 sites based on data provided by the Interstate Environmental Commission and Save the Sound. Data from 2025 will be available soon.

Challenges

Sufficient funding for needed wastewater (including OWTS) and stormwater, upgrades is a major challenge as funding is limited and much of this infrastructure is decades old. It is difficult to pin-point the locations of failing systems as they are diffuse sources.  The impacts of the changing climate including increasing temperatures, sea level rise, and more severe storms will further challenge this aging infrastructure.

Importance

The presence of pathogens is a major factor in beach and shellfish area closures and can therefore significantly inhibit some of the major human uses of Long Island Sound if not sufficiently controlled.