This glossary includes definitions of terms and acronyms that are mentioned within this website and documents that appear in the document library. Glossary terms can be searched by clicking on the first letter of the term.

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  • Bathymetry

    The varying physical characteristics–including depth, contour, sediment and shape–of the bottom of bodies of water. The bathymetry of the Gowanus varies greatly among the three reaches.

  • Benthic Community

    The group of organisms living at the bottom of a pond, river, lake or ocean.

  • Bulkhead

    A man-made structure to retain land from sliding into the waterway.

  • Dense Non-Aqueous Phase Liquid (DNAPL)

    A Dense Non-Aqueous Phase Liquid (DNAPL) that is heavier than water. These will sink to the bottom of a waterway as opposed to light Non-Aqueous Phase Liquid (NAPL)s, like oil or gasoline, that may float. NAPLs can appear as sheens on top of water.

  • Dissolved Oxygen (DO)

    A measurement of the amount of oxygen that is dissolved in water and an indicator of the quality of water. Higher levels of DO indicate better water quality.

  • Feasibility Study (FS)

    A phase in the Superfund process done following the Remedial Investigation (RI). This study develops and evaluates alternative remedial actions based upon the data collected from the RI.

  • Flushing Tunnel

    Installed in 1911, the flushing tunnel is a large propeller that brings water into the Gowanus Canal from Buttermilk Channel (between lower Brooklyn and Governor’s Island through a brick-lined 1.2-mile (1.9-km) tunnel. Rehab of the tunnel began in 1994 and it was then reactivated in 1999. An upgrade began in 2010 and it was once again reactivated in 2014.

  • In-Situ Stabilization (ISS)

    A remediation process by which contaminants are rendered immobile through reactions with stabilizing compounds mixed directly into the soil or sediment.

  • Oleophilic Clay

    A modified clay specially designed to trap contaminants through adhesion while allowing water to pass through. This material is effective in many multi-layer engineered capping applications to prevent transport of contaminants into the water column, particularly Non-Aqueous Phase Liquid (NAPL)s. Commonly found bentonite or hectorite clay is altered to produce the oleophilic clay.

  • Polychlorinated Biphenyls (PCBs)

    Polychlorinated biphenyls have a range of toxicity and vary in consistency from thin, light-colored liquids to yellow or black waxy solids. PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer and hydraulic equipment; as plasticizers in paints, plastics and rubber products; in pigments, dyes and carbonless copy paper; and many other industrial applications.

  • Polycyclic Aromatic Hydrocarbons (PAHs)

    These organic chemicals are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances. They are found in crude oil, creosote and roofing tar and are common in areas with high rates of development and motor vehicle traffic.

  • Potentially Responsible Parties (PRPs)

    Parties that may have contributed waste to the site. The United States Environmental Protection Agency (EPA) uses document reviews, site investigations, interviews, information supplied in response to information request letters, and title searches to determine a party’s liability for cleanup at a Superfund site. Contaminants on site may be due to historical, predecessor company actions over the many years of industry along the canal and not solely due to the current PRP.

  • Preliminary Assessment

    The process used by the United States Environmental Protection Agency (EPA) based on readily available information to determine if a particular site poses any threat to human health or the environment. It also makes recommendations where appropriate about possible further investigation or evaluation for corrective actions.

  • Proposed Remedial Action Plan (PRAP)

    A study of alternatives considered for remediation of a hazardous waste site and the rationale for selecting a recommended alternative. The PRAP is based on the site’s Remedial Investigation (RI) and Feasibility Study (FS). The PRAP is reviewed by the public, state agencies, and other parties and is a precursor to the Record of Decision (ROD).

  • Volatile Organic Compounds (VOCs)

    Organic compounds that can become a gas at room temperature. VOCs are the leading cause of ground-level ozone. Common sources which may emit VOCs into the air include housekeeping and maintenance products; paints, coatings, and inks; and building and furnishing materials.