Bioaccumulation and biotransformation

1. Bioaccumulation and
biotransformation
By
Pavankumar.mj

2. INTRODUCTION
• The accumulation of a substance like pesticides methyl mercury or other organic chemicals in an
organism or part of an organism is called bioaccumulation.
• Bioaccumulation refers to the gradual build-up of pollutants in living organisms.
• It is increase in concentration of a pollutant from the environment to the first organism in a food
chain.
• Organisms at any trophic level may be capable of bioaccumulation.
• The affected organism has a higher concentration of the substance than the concentration in the
organism surrounding environment.
• The substances enter the organism through respiration, food intake ,epidermal contact with
substances and other means.

3. • Kinds of Bioaccumulation
o Organismal bioaccumulation
o Trophic transfer
o Soil bioaccumulation

4. Organismal bioaccumulation
Compoundspresent in an organisms environment may concentratein the
body over time.
Example: fish that swim frequentlyin contaminated water may build up
pollutantsin their fatty tissue.
Trophic transfer
The accumulated substancetransfer from one trophiclevel to other.
Higher the trophiclevel, higher the concentrationof pollutant.
Example: organisms at the top of the food chain as humans or polar bears can
receive the highest concentration.

5. Soil accumulation
Accumultants, toxic substances that are dumped into surrounding from specific
waste site, bind to soil particles and persist until they are removed through erosion,
uptake by plantsor microorganism.

6. • Factors on which bioaccumulation depends
• Uptake of substance
• Storage of substance, storage capacity
• Elimination of substance
• Hydrophobicity
• Concentration of pollutant in water
• Age, sex and type of organism

7. • Important pollutants
o POP
o PCB
o Heavy metals

8. BIOTRANSFORMATION
• Biotransformation is the process by which a substance changes from one
chemical to another by a chemical reaction within the body.
• Metabolism or metabolic transformations are terms frequently used for
the biotransformation process.
• Biotransformation is the chemical modification made by an organism on a
chemical compound.
• If this modification ends in mineral compounds like CO2, NH4+, or H2O,
the biotransformation is called mineralisation.

9. • Phase І Reaction
o Oxidation
o Reduction
o Hydrolysis

13. • Phase II Reaction
o Conjugation
o Modification
o Modification and Excretion