Across Long Island Sound water quality is monitored by interstate, state and local agencies, academic institutions, and volunteers and community organizations. Typically, community organizations focus on rivers, bays, harbors, and inlets, while the open Sound is generally monitored by governmental agencies and academic institutions.
Monitoring consists of measuring and analyzing physical, chemical, and biological components of the Sound’s water and sediments, and its marine and plant life. Physical measurements such as temperature and salinity of water can be used to track water mass movements, which, along with levels of dissolved oxygen can indicate how suitable a particular area is for marine life. Chemical analyses of sediment and animal tissue can reveal what chemicals are present, including toxic chemicals, while data from testing of animal tissue (particularly of non-migratory organisms, such as mussels) also can be used to assess the extent to which organisms absorb contaminants.
Biological measurements, such as measuring the presence or absence of certain animal and plant life, as well as their relative numbers with respect to other organisms, also helps indicate water quality.
Monitoring can be conducted at regular sites on a continuous basis (“fixed station” monitoring); at selected sites on an ‘as needed’ basis or to answer specific questions (intensive surveys); on a temporary or seasonal basis (for example, during the summer at bathing beaches); or on an emergency basis (such as after a spill).
The Connecticut Department of Energy and Environmental Protection, on behalf of the Long Island Sound Study, conducts a Long Island Sound Water Quality
Monitoring Program. Surface and bottom waters are monitored by staff aboard the Department’s Research Vessel John Dempsey. Testing parameters include water temperature, salinity, dissolved nitrogen, particulate nitrogen, and dissolved oxygen.
The University of Connecticut Department of Marine Sciences provides real time data available on the Long Island Sound Integrated Coastal Observatory System, or LISICOS, website. Monitoring equipment affixed to four buoys in the Sound and three fixed stations on the Connecticut shoreline provides data (wave, weather and water quality) that includes water temperature, salinity, and dissolved oxygen. LISCOS also archives the cruise data described above and provides products for viewing these data. A handbook about the origins of the program, Developing and Implementing an Estuarine Water Quality Monitoring, Assessment, and Outreach Program, The MYSound Project, is available on EPA’s website. In addition, Stony Brook University, through assistance from New York Sea Grant, a few years ago operated a real time monitoring program, Sound Science aboard the Port Jefferson-Bridgeport ferry, and the University of Rhode Island, through assistance from Connecticut Sea Grant, operated a ferry-based observation program aboard the Cross Island Ferry from Orient Point in Long Island to New London. Data from these programs are still available on the Stony Brook University and University of Rhode Island websites.
The LISICOS program and the ferry monitoring programs have received financial assistance from the US EPA, through the Long Island Sound Study.
The Interstate Environmental Commission monitors dissolved oxygen conditions as well as key water quality parameters relevant to dissoloved oxygen and hypoxia in the Sound. It also coordinates with the US EPA and New York, Connecticut, and New Jersey the sampling of waste discharges from municipal and industrial plants.
New York City Department of Environmental Protection’s Harbor Water Quality Survey provides data on fecal coliform and enterococcus pathogens in the Upper East River and Western Long Island Sound that have been monitored by the DEP as well as data for water quality indicators such as dissolved oxygen levels and concentrations of microscopic plants and animals.
The US EPA’s National Coastal Condition Report assesses the coastal conditions of coastal waters from across the country derived from region by region data on water quality, sediment quality, biota, habitat, and ecosystem integrity, as they relate to ecological and human health.
In Long Island Sound, local health departments and state agencies test the water at 240 swimming beaches for disease-causing microorganisms. The most frequent sources of disease-causing microorganisms are sewage overflows, polluted stormwater runoff, sewage treatment plant malfunctions, boating wastes, and malfunctioning septic systems. Pollution in beach water most often occurs following a heavy rain when older sewage systems that have combined stormwater and sewage systems overflow, and cause untreated sewage to flow into the Sound. The US EPA’s Beaches Website provides information on whether the water at a specific beach is being monitored, who is responsible for the monitoring, the pollutants that are being monitored, and if advisories or closures have been issued. In 2015 Save the Sound also launched Sound Health Explorer, a website that grades coastal beaches by looking at high bacterial counts that lead to beach closures and comparing them to national averages. Rainfall is also featured on the site, allowing users to see which beaches suffer from bacterial contamination as a result of polluted stormwater runoff or from very local sources of fecal pollution such as a leaking municipal sewer line.