Bioaccumulation

About Bioaccumulation and Metabolism:

Measurements of bioaccumulation and metabolism obtained from standardized laboratory studies play a critical role in understanding the risks posed by chemicals to the environment and humans.  Persistent chemicals can accumulate in aquatic organisms through the direct uptake from water (bioconcentration) or through the consumption of contaminated food (biomagnification). 

Test species usually include a variety of cold and warm water fish species (trout, bluegill, carp) as well as invertebrates such as oysters, aquatic worms, and earthworms.

Bioaccumulation in Fish: Aqueous and Dietary Exposure (determination of BCF and BMF):

Aqueous bioconcentration studies are conducted to assess bioaccumulation of potentially toxic chemicals in aquatic organisms, measured  by a chemical’s bioconcentration factor (BCF) in fish.  Fish are usually exposed to the chemical dissolved in water and the BCF is calculated as the ratio of the concentration in the fish to the dissolved concentration in water at “steady-state”, or by the ratio of the uptake and depuration rate constants.  For poorly soluble substances where stable and measurable concentrations are difficult to obtain in the exposure medium,  bioaccumulation can be assessed  using adosing method involving test substance spiked feed, resulting in a dietary biomagnification factor orBMF (the ratio of the substance in the animal’s body to the concentration in food).  For a majority of chemicals, kinetic bioconcentration factor (BCFk) can be estimated from a BMF study, where fish andfish food are collected and analyzed during the course of the test.  

Typically a flow-through test system is used to expose fish to test chemicals in aqueous solution for both tests.  Fish and water samples are collected and analyzed at certain intervals during the course of thetest to ultimately determine uptake and depuration rate constants or bioconcentration factors. .  In addition, metabolism of chemicals can be conducted by quantifying and identifying residues in test organisms. If necessary, fish in both BCF and BMF tests can be divided into edible and non-edible fractions for analysis.

 

Bioaccumulation in Sediment-dwelling Benthic Oligochaetes (determination of BAF and BSAF):

These tests are designed to assess bioaccumulation of sediment-associated chemicals in endo benthicoligochaetes.  The test organisms are exposed to chemicals via multiple uptake routes, including direct ingestion of sediment, surface contact and ingestion of pore water.  Oligochaetes, sediment and overlying water samples are collected analyzed at specified intervals during the course of the test. The primary endpoints are a bioaccumulation factor (BAF) and a biota-sediment accumulation factor (BSAF).

 

Bioaccumulation in Terrestrial Oligochaetes (BAF and BSAF):

These tests are designed to assess bioaccumulation of soil-associated chemicals in terrestrial oligochaetes.  The test organisms are exposed to soil dosed with the test chemicals and oligochaetes and soil are collected and analyzed at certain intervals during the course of the test.  The primary endpoints are a bioaccumulation factor (BAF) and a biota-soil accumulation factor (BSAF).

 

Smithers Viscient’s Bioaccumulation and Metabolism Study Expertise:
Our team has decades of experience in bioaccumulation testing of various test chemicals including agrochemicals, pharmaceuticals and industrial compounds.  Our scientific experts can offer customized studies to meet specific regulatory needs for difficult to test chemicals, and consulting in support of overall environmental risk assessment.

 

Guidelines:

OECD.  (2012), Test No. 305: Bioaccumulation in Fish: Aqueous and Dietary Exposure, OECD Guidelines for the Testing of Chemicals, Section 3, OECD Publishing, Paris.

U.S. EPA. (1996), Office of Prevention, Pesticides and Toxic Substances. Ecological Effects Guideline, OPPTS 850.1730.  Fish BCF.  "Public Draft". EPA 712-C-96-129. April 1996.  U.S. Environmental Protection Agency, Washington, D.C.

OECD.  (2008), Test No. 315: Bioaccumulation in Sediment-dwelling Benthic Oligochaetes, OECD Guidelines for the Testing of Chemicals, Section 3, OECD Publishing, Paris.

OECD.  (2010), Test No. 317: Bioaccumulation in Terrestrial Oligochaetes, OECD Guidelines for the Testing of Chemicals, Section 3, OECD Publishing, Paris

 

Equipment and Instrumentation includes:

  • Flow-through test systems
  • Agilent, Shimadzu, and Waters HPLC systems
  • Metabolite characterization and identification instrumentation: Sciex 4000 QTRAP® and accurate mass Sciex Triple TOF 5600 Q® mass spectrometers