The Bronx River, which flows through urban areas of Westchester County and the Bronx until it reaches the East River, has been significantly impacted by anthropologic influences. The entirety of this river is classified as “impaired” according to New York State water quality classifications. Stormwater runs down through urban areas in this watershed and may collect pollutants, including pathogens, that are discharged directly into the Bronx River through Municipal Separate Storm Sewer System (MS4) outfalls, potentially contributing to these water quality impairments.

The New York State Department of Health Environmental Laboratory Accreditation Program has just approved two new laboratory certifications for IEC’s laboratory: Determination of Total Microcystins and Nodularins in Drinking Water and Ambient Water by Adda Enzyme-Linked Immunosorbent Assay (ELISA) and Determination of Total Organic Carbon (TOC) and Dissolved Organic Carbon in Non-Potable Waters. With these new certifications, IEC will be able to expand its abilities to include more comprehensive testing of water quality and health.

During the winter months when temperatures drop and recreational water uses decrease, water quality data is generally taken less frequently. Freezing conditions can pose many challenges for sampling in this season. During this colder-than-average winter, which produced large amounts of snow and ice, data has been especially difficult to collect. Thick sheets of ice occasionally prevented boats from getting out on the New York-New Jersey Harbor, the Long Island Sound, or the Hackensack River, where IEC does the majority of our boat-based sampling.

IEC's annual State Summaries are now published, providing an overview of the organization's work and impact in its three member states throughout the fiscal year 2024-2025. In addition to water quality programs, collaborative activities are shared, including workgroups and committees, public education and outreach.

IEC’s annual open house was a success! Thank you to everyone who stopped by and took the time to explore our programs and the work that we have been doing this past year. For those who could not attend, check out our posters below! Click on any of the snapshots of posters to enlarge them or scroll to the bottom of the page and scroll through the PDF with all of the posters.

Pending approval by the NYSDOH Environmental Laboratory Approval Program, IEC will be certified in Standard Method 5310B-14: Determination of Total Organic Carbon (TOC) and Dissolved Organic Carbon (DOC) in Non-Potable Waters. This method uses combustion and an oxidation catalyst within a TOC analyzer machine to remove any inorganic carbon and purgeable organic carbon, isolating the organic carbon, which is then converted to CO2. The CO2 is then transported to a non-dispersive infrared detector using carrier gas and measured by software in the machine.

Check out these summer 2025 time-lapse videos depicting dissolved oxygen levels in the western Long Island Sound! These visualizations were developed using surface (1 meter depth) and bottom (1 meter above sediment) dissolved oxygen measurements taken by IEC during our weekly water quality surveys in summer 2025. Low or depleted dissolved oxygen levels in a waterbody is referred to as hypoxia. Hypoxia can result in significant adverse effects on marine life and habitats, which need sufficient dissolved oxygen (>5.00mg/L) to survive and thrive.

In conjunction with New York/New Jersey Harbor and Estuary Program (HEP), EPA, and Stony Brook University, Interstate Environmental Commission (IEC) is monitoring the success of eelgrass plants planted by Stony Brook University adjacent to the Living Breakwaters on the southern coast of Staten Island. The success of these plants is measured using both habitat and water quality parameters in the summer and fall of 2025 and the spring of 2026. Eelgrass has several vital functions in aquatic ecosystems and can improve water quality and habitat stability.

Pending approval by the NYSDOH Environmental Laboratory Approval Program, IEC will be certified for EPA Method 546: Determination of Total Microcystins and Nodularins in Drinking Water and Ambient Water by Adda Enzyme-Linked Immunosorbent Assay (ELISA). This method measures the total concentration of microcystins based on the detection of a characteristic feature common to microcystins using absorbance of the sample after it has been treated for analysis.

Through funding provided by the Long Island Sound Partnership (LISP), IEC has secured a subaward to support Coalition to Save Hempstead Harbor (CSHH), a group which conducts water-quality monitoring of physical, chemical, and biological indicators of pollution at up to 21 sites in Hempstead Harbor and Glen Cove Creek.