Bio-uptake assessment

This procedure determines the uptake and elimination kinetics of ENMs or metals in test organisms, both soil and aquatic.

1. Uptake phase:

  • Sample test medium at start and end;
  • Expose test organisms to one or two selected concentrations of test chemical;
  • Include also controls without test chemical;
  • Collect organisms at different time points.
2. Elimination phase:
  • At end of uptake phase, transfer remaining animals to clean medium;
  • Sample organisms at different time points.
3. Analytical phase:
  • Analyze test medium sampled at start and end of uptake phase to check for exposure concentrations;
  • Analyze sampled organisms for uptake and elimination of the test chemical.
4. Kinetics calculation phase:
  • Calculate average measured exposure concentrations;
  • Calculate uptake and elimination rate constants;
  • Apply first-order one-compartment model.

Mechanisms & Methods

  • Prepare at least 3 replicate test containers for each sampling time;
  • Also include at least 3 replicate control containers, but only for start and end of each phase;
  • Sample t=0 organisms from batch of organisms used to start exposures;
  • In case of soil-ingesting animals, allow gut voiding using appropriate method;
  • In case of plant roots, remove adhering soil particles;
  • Store biological samples in freezer and, for metal analysis, freeze dry samples and digest in suitable acid;
  • For metal analysis, also analyze suitable certified reference material (soil, biological sample) to check for quality of analysis;
  • Calculate uptake rate constant (k1) and elimination rate constant (k2) using suitable model; include C0 in case test organisms already contain background concentration of the test chemical (e.g. metal).

Read more

Read also
 

 

OECD (2010) Guidelines for the Testing of Chemicals No. 317: Bioaccumulation in Terrestrial Oligochaetes. Organisation for Economic Co-operation and Development, Paris, France.

OECD (2012) Guidelines for the Testing of Chemicals, No. 305: Bioaccumulation in Fish: Aqueous and Dietary Exposure. Organisation for Economic Co-operation and Development, Paris, France.

 

Contact

 

Kees van Gestel

Department of Ecological Science
Faculty of Science, Vrije Universiteit

Email: kees.van.gestel@vu.nl