Appendix 2: Glossary of Terms

Accretion – The accumulation of sediment, deposited by natural fluid flow processes.

Anadromous fish – Fish that hatch in freshwater, migrate to the ocean to mature, then return to freshwater to spawn.

Anthropogenic – Pertains to the influence of human activities.

Atmospheric deposition – The process by which particles suspended in the air are deposited by precipitation or wind in the ocean, rivers, or on land.

Benthic – Refers to material, especially sediment, at the bottom of an aquatic ecosystem. It can be used to describe the organisms that live on, or in, the bottom of a waterbody.

Biological Nutrient Removal (BNR) – The removal of nutrients, such as nitrogen and/or phosphorous during wastewater treatment.

Biological Oxygen Demand (BOD) – A measurement of the oxygen demand of organic material which, when breaking down in water, consumes oxygen in the water column.

Catch basin – An inlet to a storm or combined sewer equipped with a sediment sump, and sometimes a hood, on its outlet pipe to the sewer. Catch basins prevent clogging of sewers by sediment and debris washed off streets, and provide a water seal against the venting of sewer gases.

Chlorophyll-a – A plant pigment whose concentration in water is used to estimate the amount of phytoplankton or algae.

Combined Sewer Overflow (CSO) – An event where the discharge of untreated human and industrial sewage and stormwater into local waterways occurs when the capacity of a combined storm/sanitary sewer system is exceeded by local runoff.

Dissolved Oxygen (DO) – Amount of oxygen gas dissolved in a given volume of water at a particular temperature and pressure. This term also refers to a measure of the amount of oxygen available for biochemical activity in a waterbody, an indicator of the quality of that water.

Effluent – Municipal sewage or industrial liquid waste (untreated, partially treated, or completely treated) that flows out of a treatment plant, septic system, pipe, etc.

Enterococcus – Common bacterial species found in the intestines of humans and animals; recently took the place of fecal coliform as the new federal standard for water quality at public beaches.

Estuary – Region of interaction between rivers and near-shore ocean waters, where tidal action and river flow mix fresh and salt water.

Eutrophication – Biological phenomenon of excessive nutrient load, heightened vegetative growth and subsequent low dissolved oxygen levels in water ecosystems.

Fecal Coliform – Indicator organisms, associated with the digestive tract, that indicate the presence of raw or partially treated sewage.

Floatables – Made up primarily of manmade debris, they contribute to beach closures, interfere with navigation, entangle wildlife and impair aesthetics.

Geometric mean – A measure of the central tendency of a data set that minimizes the effects of extreme values.

Humic material – Highly decomposed organic material.

Limiting nutrient – A nutrient, whose concentration in the environment of an organism, determines the growth and productivity of that organism.

Micrograms per Liter (ug/L) – one part per billion by weight.

Milligrams per Liter (mg/L) – one part per million by weight.

Nitrification – The process by which ammonia is changed to nitrite, then nitrate, and finally nitrogen gas.

Non-point sources of pollution (NPSP) – Contaminants and particulates that flow with rainwater runoff into waterways, or that move through the atmosphere and are deposited onto the land or water.

PCB – Polychlorinated Biphenyl, a synthetic, organic chemical once widely used in electrical equipment, specialized hydraulic systems, heat transfer systems, and other industrial products. Considered to be toxic and a potent carcinogen.

pH – Measure of the relative acidity or alkalinity of water.

Photosynthesis – a process used by plants to convert water, carbon dioxide, and sunlight into carbohydrates and oxygen.

Point source – Pollutant loads discharged at a specific location from pipes, outfalls, and conveyance channels from either municipal wastewater treatment plants or industrial waste treatment facilities. Point sources can also include pollutant loads contributed by tributaries to the main receiving water stream or river.

Primary treatment – Refers to the removal of course material through screening and settling, in wastewater treatment.

Residence time – The amount of time water remains inside a specified area, e.g., harbor, bay, etc.

Salinity – The total quantity of dissolved salts in water, usually measured by weight in milligrams per liter (mg/L) or parts per million (ppm).

Salinity gradient – A change in salinity between bodies of water or layers within a body of water.

Secchi depth – A parameter used to determine the clarity of surface waters, using a secchi disk.

Secondary treatment – Refers to the biological and chemical removal of organic matter, in wastewater treatment.

Seepage basin – Catch basins that allow collected water to eventually seep into the ground.

Superfund – Federal authority, established by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) in 1980, to respond directly to releases or threatened releases of hazardous substances that may endanger health or welfare.

Total Suspended Solids (TSS) – Solids suspended in water including a wide variety of material such as silt, decaying plant matter, industrial wastes and sewage.

Wastewater treatment – Chemical, biological, and mechanical procedures applied to an industrial or municipal discharge or to any other sources of contaminated water to remove, reduce, or neutralize contaminants.