Biomagnification, described

Describe in words, the parameters (1) bioconcentration factor, (2) biomagnification factor, (3) biota-sediment- and biota-soil- accumulation factor, and (4) bioaccumulation factor. 

Biomagnification can be described by a biomagnification factor (BMF), which is the ratio of the chemical concentration in the organism to the concentration in the organism s diet ... 

Bioaccumulation is the result of simultaneous bioconcentration and biomagnification. It usually is observed under field conditions but can be measured in laboratory experiments, as well. In terms of a toxicokinetic model, where the organism is presented as a single compartment, addition of equations (13) and (25) can describe the bioaccumulation of a chemical in an organism ... 

Several terms have been used to describe this phenomenon, namely, biomagnification, bioconcentration, and bioaccumulation. However, the pesticide is not always concentrated or magnified as it moves up to the food chain, so the latter term is preferable (Nakatsugawa and Nelson, 1972). For example, dieldrin residue in cod at 0.009 ppm (whole fish bases) was less than in the sand eel, the major diet of the cod, at 0.016 ppm. Dieldrin residue in a macrozooplankton (crustacea) at 0.16 ppm was higher than in any of the fish examined... 

Bioaccumulation The accumulation of xenobiotic substances in organisms and the food chain is important in the assessment of the harmfiilness of a substance in the environment. The accumulation of organic substances in organisms occurs often in accordance with their lipophilicity (Figure 9.29) A ow often serves as a measure of lipophilicity and as a predictive parameter for bioaccumulation in the food chain. One also speaks of biomagnification to describe progressive accumulation of xenobiotic substances in the food chain. 

In the present study, bioconcentration, biomagnification and bioaccumulation models are presented using models which describe the concentrations of chemicals in the organisms and environment and food. Other models use fugacities to describe the bioaccumulation processes [e.g. 19,20]. For the sake of simplicity, however, we continue with describing the models based on concentrations. 

The term bioaccumulation is often used to describe the overall build-up of contaminants within the tissues of an organism. However, sometimes more specific terminology is used to reflect the different routes for absorption of contaminants, with bioconcentration used to denote passive absorption through skin or gills, while bioaccumulation is reserved for ingestion of particulates (feeding) and biomagnification is used to describe the cumulative effects over successive trophic levels in a food chain (Franke et al. 1994). 

Xenobiotics enter in the bloodstream, following one of the described absorption routes, are distributed into the body and undertaken by different organs. It is possible that a part of the xenobiotics distributed into the body may be stored in tissues or even in the blood. A word commonly used to refer to storage of a pollutant at higher levels than those found in the environment is bioaccumulation, for example, PAHs, PCBs, dioxins and some organometallic forms of metals bioaccumulate in fat, fluoride and lead in bones etc. Sometimes biomagnification takes place, as a bioaccumulation process within the trophic chain, in indirect relationship with biota. 

To date, no sign of essentiality for plants, animals, and humans have been reported for cesium neither has any biomagnification by fauna been described, and soil concentrations of cesium are always much higher than that of both plants and animals. Cesium bioconcentration has not been observed in any specialized parts of plants, except for the skin of the hats of certain types of mushrooms, wherein cesium (detected as radiocesium) accumulates to high levels. In this situation it is thought that the cesium is enriched in the color pigments of the hat skin (Kalac, 2001). The potassium content of the mushroom was also found to relate inversely to the cesium content in other words, the higher the potassium content, the lower the cesium content (Marin et al., 1997). 

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