OECD 305 – Bioaccumulation in Fish: Aqueous and Dietary Exposure

OECD 305 is a bioaccumulation test performed with freshwater, estuarine, or marine fish species.

The OECD 305 method measures the residues of a test substance in fish after exposure to the test substance in an aqueous environment.  There are three different methods within the OECD 305 methodology:

  • Part I: Aqueous Exposure Bioconcentration Test
  • Part II: Minimized Aqueous Exposure Test
  • Part III: Dietary Exposure Bioaccumulation Test

Each method consists of two phases: the uptake phase and depuration phase.

Bioaccumulation rate is assessed after both phases are complete. OECD 305 testing is useful for any chemical that may come into contact with an aqueous environment.

Test Organisms

Danio rerio (zebra fish) is the most commonly used test organism.

A variety of freshwater, estuarine and marine fish species are acceptable according to OECD 305; please inquire with the lab for any project specific species requirements prior to project initiation.

Method Summary

In the OECD 305, fishes are exposed to the test substance in water from 7- 28 days, depending on which method is executed; this is known as the uptake phase. At the end of the uptake phase, the fish from remaining test units are transferred to untreated water for up to 28 days, depending which method is executed; this is known as the depuration phase.

Measurements of the fish are recorded a number of times throughout the uptake and depuration phase.


Three parameters determine the sample’s bioaccumulation: bioconcentration factor (BCF), uptake rate constant (ks) and elimination rate constant (ke).

Information on the toxicity of the sample to the test fish is required prior to testing. Determination of the LC50 is recommended in order to determine the test concentration to use for bioaccumulation testing.

For more information on OECD 305, contact the lab at 847-483-9950 or info@situtest.com