Bioaccumulation refers to the accumulation of substances in living organisms.  Many organisms may be exposed to toxic substances that find their way into sediment or aqueous environments. It is important to test chemicals and formulations for their bioaccumulation potential, as it offers valuable information on their ecotoxicological properties.  Regulatory agencies monitor bioaccumulation to determine whether chemicals are associated with or responsible for adverse effects on the environment.

Any substance with low biodegradation potential that is released into the environment has the potential to bioaccumulate.  Perhaps the most concerning substances are the persistent organic pollutants (POPs) that exhibit endocrine-disrupting properties in organisms. POPs are inherently lipophilic, meaning these compounds readily bioaccumulate in organisms, and increase cumulatively at each trophic level. POPs are often released into the environment through industrial accidents and discharges, landfill leakage, or incomplete incineration. These substances do not naturally degrade so they may persist in the environment potentially indefinitely.

Regulatory Information

Bioaccumulation in aquatic species is a standard information requirement under Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Annex IX, 9.3.2.

For REACH compliance, information on bioaccumulation is used in:

  • Persistence, Bioaccumulative and Toxic Substances (PBT) assessment
  • Hazard classification
  • Chemical safety assessment (food chain exposure modeling)
  • Additionally, information on bioaccumulation is also a key factor in deciding if it is necessary to perform long-term ecotoxicity testing

For Reach compliance, Bioaccumulation studies generally do not need to be conducted if the following criteria are met (

  • The substance has a low potential for bioaccumulation (for instance *log KOW =< 3) and/or a lower potential to cross biological membranes, or
  • Direct and indirect exposure of the aquatic compartment is unlikely

* n-Octanol-water partition coefficient (OECD 107, OECD 117 and OECD 123)

Either exception requires reports of reliable data submitted.  For example, if claiming no direct or indirect exposure of aquatic compartments, there must be a reliable demonstration supporting that there is no release to the environment at any stage in the substance’s life cycle.

Testing Options

Bioaccumulation testing is commonly performed with Oligochaetes or Fish.

Customers Commonly request the following methods:

Bioaccumulation Methods:
OECD 305: Bioaccumulation in Fish: Aqueous and Dietary Exposure
OECD 315: Bioaccumulation in Sediment-dwelling Benthic Oligochaetes
OECD 317: Bioaccumulation in Terrestrial Oligochaetes

Another commonly requested study analyzing a material’s Environmental Fate is Biodegradation Testing.

For more information on Environmental Fate & Toxicology testing, contact the lab at 847-483-9950 or