Bioaccumulation and bioavailability

Question 1

How to assess exposure to chemicals?

Answer 1

Humans

1. Food
   - digestive track
   - blood
2. Respiration
   - lungs
   - blood circulation
3. Skin

Aquatic organisms
- Food, gills, skin

Question 2

What is bioconcentration?

Answer 2

accumulation of a chemical in or on an organism when the source of chemical is solely water.

Question 3

What is a better way to estimate bioavailability than total concentration?

Answer 3

Free, dissolved chemical concentration.

Question 4

What is desorption?

Answer 4

Desorption is the physical process where a previously adsorbed substance is released from a surface.
This happens when a molecule gains enough energy to overcome the activation barrier or the bounding energy that keeps it in the surface.

Question 5

Why is partitioning coefficient important?

Answer 5

Helps to understand chemicals environmental behavior.

They describe the chemicals tendency to divide between the two different phases:
– Sediment and water (Koc)
– Water and air (Kaw)
– Organism and water, organism and soil, organism and sediment (BCF, BAF, BSAF)
– Predator and prey (BMF)