Bioaccumulation Flashcards
Define pollution.
Human activity that releases unwanted and damaging substances into the environment.
What does toxic pollution refer to?
Substances which are harmful to the health/toxic to organisms.
What does the toxicity or a chemical correspond to and what is it influenced by?
The damage it can do if discharged into the environment. Dose concentration and length of exposure.
What is meant by specificity?
The term refers to the fact that some chemicals cause more damage to sensitive groups of organisms.
Are specific or non-specific chemicals more hazardous?
Generally the non-specific ones are, as they can affect many types of organisms.
Define bioaccumulation.
indicates that the concentration of pollutants within an organism, trophic level or community is greater than the concentration of the pollutant in the environment.
When does bioaccumulation occur?
When the rate of absorption of a pollutant is greater than its combined rates of degradation and excretion.
Define biomagnification
the levels of a pollutant are found to be at a higher concentrations in organisms of successive trophic leves.
How does biological magnification occur
The pollutant accumulates at each trophic transfer.
What is the consequence of biological magnification?
Low or harmless initial environmental concentrations rapidly become toxic or lethal in top predators (examples are insecticide DDT and mercury).
What is biotransformation of a pollutant?
The chemical changes it may undergo once it has entered an organism. It may be transformed to a more or less harmful compound.
Define and give an example of a persistent pollutant.
Mercury and DDT, non-biodegradable.
What is the effect of mercury pollution?
Human poisoning, there was biological magnification through marine food chain.
What is the effect of DDT and DDE in birds?
Reduces calcium content of eggs of birds which have been intoxicated through biomagnification and bioaccumulation. Results in lower hatching and survival rate of large prey birds (eg osprey).
