Bioconcentration factor

Bioconcentration factor (BCF) is the concentration of a particular chemical in a biological tissue per concentration of that chemical in water surrounding that tissue. That is, a dimensionless number representing how much of a chemical is in a tissue relative to how much of that chemical exists in the environment.

$BCF = \frac{Concentration_{Organism}}{Concentration_{Environment}}$

This physical property characterizes the accumulation of chemicals, including pollutants, through chemical partitioning from the aqueous phase into an organic phase. This may occur as in gills of a fish, or cell walls of aqueous plants.

In the context of setting exposure criteria it is generally understood that the terms "BCF" and "steady-state BCF"' are synonymous. A steady-state condition occurs when the organism is exposed for a sufficient length of time that the ratio does not change substantially.

Tissues with BCF greater than 1,000 are considered high, and under 250 low, with those between classified as moderate.

See also

• Bioaccumulation
• Biomagnification

BCF is correlated to the Partition coefficient via a logarithmic equation of the form $\log BCF = Y \times \log KOW - Z$ where Y ranges from 0 and 1 depending on the compound.