Bioconcentration, definition

US Geological Survey. 2013. Bioconcentration - Definitions. Web page last updated... 

By definition a bioconcentration in the organisms are relevant, if the bioconcentration factor (BCF) is higher than 100. 

To indicate the transfer of chemicals in a biogeochemical food web, both bioaccumulation factors (BAFs) and bioconcentration factors (BCFs) are used. The following definitions can be applied (de Vries and Bakker, 1998a, 1998b) ... 

Using ku as the rate constant for uptake and ke as the rate constant for elimination leads to the following definition of bioconcentration factor ... 

The definition of bioconcentration has to be distinguished from the terms of indirect contamination such as biomagnification, bioaccumulation, and ecological magnification [12,19]. 

Bioconcentration and bioaccumulation (in its more restricted definition) can operate together, and determining their precise contributions can be extremely difficult. For example, tributyl tin (TBT) is relatively soluble in water, so the dog whelk absorbs it across its gills and mantle tissue, but it can also absorb a significant proportion from its food (Section 7.5.1 Bryan et al. 1989 Langston 1996). Throughout this book bioaccumulation is used in its most general sense. 

By rearrangement of equation (4), we can relate the bioconcentration factor to the rate constants for uptake and clearance of the toxicant. This may be compared with the earlier definition ofBCF based on equilibria the advantage of the kinetic definition is that the BCF may be deduced in cases where equilibration has not been achieved, provided that the rate constants can be estimated... 

Bioaccumulation in aquatic species is essentially bioconcentration plus uptake by any other process such as ingestion of food, and usually applies to field observations where the routes of exposure are not known. The quantitative definition again is the ratio of the concentrations of the chemical in the... 

If the rate of entry of the chemical into the the resident biota exceeds the rate at which it can be excreted, two evenmalities occur. The first is that the chemical can be transformed into another one that can be dealt with more easily. On the other hand, if the chemical cannot be transformed, then it will accumulate with the organism s tissues, increasing the bioconcentration of the compound. Bioconcentration, like bioavailability, has a very specific definition, as it is the process by which a chemical directly enters into aquatic organisms from water. Often it is presented in terms of a bioconcentration factor, which relates the concentration of a chemical in the organism relative to the concentration of the chemical in the water. For chemicals that tend... 

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