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Biomagnification, also known as bioamplification, or biological magnification is the increase in concentration of a substance, such as the pesticide DDT, that occurs in a food chain as a consequence of:

Although sometimes used interchangeably with 'bioaccumulation,' an important distinction is drawn between the two, and with bioconcentration. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at ftudruinsubstance is lost

Thus bioconcentration and bioaccumulation occur within an organism, and biomagnification occurs across trophic (food chain) levels. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at ftudruinsubstance is lost

Lipid soluble (lipophilic) substances cannot be excreted in urine, a water-based medium, and so accumulate in fatty tissues of an organism if the organism lacks enzymes to degrade them. Lipids are broadly defined as any fat- Soluble ( lipophilic) naturally-occurring Molecule, such as fats oils waxes cholesterol sterols fat-soluble Lipophilicity, fat-liking, refers to the ability of a Chemical compound to dissolve in fats oils lipids and non-polar solvents such as Hexane or Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. "Adipose" redirects here For the Doctor Who monster see " Partners in Crime " Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins When eaten by another organism, fats are absorbed in the gut, carrying the substance, which then accumulates in the fats of the predator. Since at each level of the food chain there is a lot of energy loss, a predator must consume many prey, including all of their lipophilic substances.

For example, though mercury is only present in small amounts in seawater, it is absorbed by algae (generally as methylmercury). Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Seawater is Water from a Sea or Ocean. On average seawater in the world's oceans has a Salinity of about 3 Methylmercury (sometimes methyl mercury) is an Organometallic Cation with the formula + It is efficiently absorbed, but only very slowly excreted by organisms (Croteau et al, 2005). Bioaccumulation and biomagnification result in buildup in the adipose tissue of successive trophic levels: zooplankton, small nekton, larger fish etc. Zooplankton are the Heterotrophic (sometimes detritivorous) type of Plankton. Nekton refers to the aggregate of actively swimming aquatic organisms in a body of water (usually oceans or lakes able to move independently of water currents Anything which eats these fish also consumes the higher level of mercury the fish have accumulated. This process explains why predatory fish such as swordfish and sharks or birds like osprey and eagles have higher concentrations of mercury in their tissue than could be accounted for by direct exposure alone. Swordfish ( Xiphias gladius) are large highly migratory Predatory Fish characterized by a long flat bill. Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body The Osprey (Pandion haliaetus, also called Sea Hawk, is a diurnal, fish-eating Bird of prey. Eagles are large birds of prey which are members of the Bird order Falconiformes and family Accipitridae, and belong to several genera For example, herring contains mercury at approximately 0. 01 ppm and shark contains mercury at greater than 1 ppm (EPA 1997).

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Current status

In a review of a large number of studies, Suedel et al (1994) concluded that although biomagnification is probably more limited in occurrence than previously thought, there is good evidence that DDT, DDE, PCBs, toxaphene, and the organic forms of mercury and arsenic do biomagnify in nature. DDT (from its trivial name D ichloro- D iphenyl- T richloroethane is one of the best known synthetic Pesticides It is a chemical with a long Dichlorodiphenyldichloroethylene (11- bis -(4-chlorophenyl-22-dichloroethene is the full name of DDE Polychlorinated biphenyls ( PCB s are a class of Organic compounds with 1 to 10 Chlorine atoms attached to Biphenyl which is a molecule composed Toxaphene is an Organic compound with the approximate Empirical formula C10H10Cl8 and average Molecular mass of 414 Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Arsenic (ˈɑrsənɪk is a Chemical element that has the symbol As and Atomic number of 33 For other contaminants, bioconcentration and bioaccumulation account for their high concentrations in organism tissues. More recently, Gray (2002) reached a similar conclusion. However, even this study was criticized by Fisk et al. , (2003) for ignoring many relevant studies. Such criticisms are spurring researchers to study carefully all pathways, and Croteau et al. (2005) recently added Cadmium to the list of biomagnifying metals.

The above studies refer to aquatic systems. In terrestrial systems, direct uptake by higher trophic levels must be much less, occurring via the lungs.

This critique of the biomagnification concept does not mean that we need not be concerned about synthetic organic contaminants and metal elements because they will become diluted. Bioaccumulation and bioconcentration result in these substances remaining in the organisms and not being diluted to non-threatening concentrations. The success of top predatory-bird recovery (bald eagles, peregrine falcons) in North America following the ban on DDT use in agriculture is testament to the importance of biomagnification. The Bald Eagle ( Haliaeetus leucocephalus) is a Bird of prey found in North America that is most recognizable as the national bird and The Peregrine Falcon ( Falco peregrinus) also known simply as the Peregrine, and historically as the "Duck Hawk" in North America is a

Substances that biomagnify

There are two main groups of substances that biomagnify. Both are lipophilic and not easily degraded. Novel organic substances are not easily degraded because organisms lack previous exposure and have thus not evolved specific detoxification and excretion mechanisms, as there has been no selection pressure from them. eVolution is the third Album by eLDee, it was due to be released in 2008 These substances are consequently known as 'persistent organic pollutants' or POPs. Persistent organic pollutants ( POP s are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic

Metals are not degradable because they are elements. Organisms, particularly those subject to naturally high levels of exposure to metals, have mechanisms to sequester and excrete metals. Problems arise when organisms are exposed to higher concentrations than usual, which they cannot excrete rapidly enough to prevent damage. These metals are transferred in an organic form.

Novel organic substances

Further information: Persistent Organic Pollutant

Inorganic substances

References

Dictionary

biomagnification

-noun

  1. (biology) The process, in an ecosystem, in which a higher concentration of a substance in an organism is obtained higher up the food chain
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