Selenium pollution
Encyclopedia
In high concentrations, selenium
acts as an environmental contaminate. Sources of pollution include waste materials from certain mining, agricultural, petrochemical, and industrial manufacturing operations. In Belews Lake
North Carolina, 19 species of fish were eliminated from the lake due to 150-200 ug Se/L wastewater discharged from 1974 to 1986 from a coal-fired power plant. At the Kesterson National Wildlife Refuge in California, thousands of fish and waterbirds were poisoned by selenium in agricultural irrigation drainage.
Substantial physiological changes may occur in fish with high tissue concentrations of selenium. Fish affected by selenium may experience swelling of the gill lamellae, which impedes oxygen diffusion across the gills and blood flow within the gills. Respiratory capacity is further reduced due to selenium binding to hemoglobin
. Other problems include degeneration of liver tissue, swelling around the heart, damaged egg follicles in ovaries, cataracts, and accumulation of fluid in the body cavity and head. Selenium often causes a malformed fish fetus which may have problems feeding or respirating, distortion of the fins or spine is also common. Adult fish may appear healthy despite their inability to produce viable offspring.
Selenium is bioaccumulated
in aquatic habitats, this results in higher concentrations in organisms than the surrounding water. Organoselenium compounds can be concentrated over 200,000 times by zooplankton
when water concentrations are in the .5 to .8 ug Se/L range. Inorganic selenium bioaccumulates more readily in phytoplankton
than zooplankton. Phytoplankton can concentrate inorganic selenium by a factor of 3000. Further concentration through bioaccumulation occurs along the food chain, as predators consume selenium rich prey.It is recommended that a water concentration of 2 ug Se/L be considered highly hazardous to sensitive fish and aquatic birds. Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations.Reproduction of mallard ducks is impaired at dietary concentrations of 7 ug Se/g. Many benthic invertebrates can tolerate selenium concentrations up to 300 ug Se/g in their diet.
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
acts as an environmental contaminate. Sources of pollution include waste materials from certain mining, agricultural, petrochemical, and industrial manufacturing operations. In Belews Lake
Belews Lake
Belews Lake is a reservoir in Stokes, Rockingham, Guilford and Forsyth counties of North Carolina, near the towns of Stokesdale and Pine Hall. It was created in 1973 by the Duke Energy corporation to provide cooling water for the corporation's Belews Creek Steam Station, a coal-burning power...
North Carolina, 19 species of fish were eliminated from the lake due to 150-200 ug Se/L wastewater discharged from 1974 to 1986 from a coal-fired power plant. At the Kesterson National Wildlife Refuge in California, thousands of fish and waterbirds were poisoned by selenium in agricultural irrigation drainage.
Substantial physiological changes may occur in fish with high tissue concentrations of selenium. Fish affected by selenium may experience swelling of the gill lamellae, which impedes oxygen diffusion across the gills and blood flow within the gills. Respiratory capacity is further reduced due to selenium binding to hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
. Other problems include degeneration of liver tissue, swelling around the heart, damaged egg follicles in ovaries, cataracts, and accumulation of fluid in the body cavity and head. Selenium often causes a malformed fish fetus which may have problems feeding or respirating, distortion of the fins or spine is also common. Adult fish may appear healthy despite their inability to produce viable offspring.
Selenium is bioaccumulated
Bioaccumulation
Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost...
in aquatic habitats, this results in higher concentrations in organisms than the surrounding water. Organoselenium compounds can be concentrated over 200,000 times by zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
when water concentrations are in the .5 to .8 ug Se/L range. Inorganic selenium bioaccumulates more readily in phytoplankton
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
than zooplankton. Phytoplankton can concentrate inorganic selenium by a factor of 3000. Further concentration through bioaccumulation occurs along the food chain, as predators consume selenium rich prey.It is recommended that a water concentration of 2 ug Se/L be considered highly hazardous to sensitive fish and aquatic birds. Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations.Reproduction of mallard ducks is impaired at dietary concentrations of 7 ug Se/g. Many benthic invertebrates can tolerate selenium concentrations up to 300 ug Se/g in their diet.