Bioaccumulation the accumulation of a contaminant or toxin in or on an organism from all sources eg food water air An increase in the concentration of a chemical in a biological organism over time compared to the chemicals concentration in the environment Compounds acc ID: 272836
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Slide1
What is bioaccumulation?
Slide2
Bioaccumulation
= the accumulation of a contaminant or toxin in or on an organism from all sources (e.g., food, water, air). An increase in the concentration of a chemical in a biological organism over time, compared to the chemical's concentration in the environment. Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted.
Slide3
What is
biomagnification
? Slide4
Biomagnification
= the increase in concentration of toxin as it passes through successive levels of the food webDDE accumulates at higher levels in organisms that are higher in the food chain Slide5
In the body of an animal, DDT is changed (metabolized) to DDE.
DDE dissolves in fat, not in water, and is stored in fatty tissues. Thus, DDE tends to remain in the body and can cause several problems. Slide6
How does DDT move into lakes, streams and oceans?
Slide7
After DDT is applied, some DDT volatizes, some remains on the plant, and some washes off the plant into the soil, eventually making its way to a
a stream, river, or lake. The DDT that remains on the leaves of plants may be ingested by primary consumers such as insects and rodents. DDT that has washed into a waterbody, remains in the sediment or is consumed by bottom-feeding organisms or absorbed by fish gills and skin. Slide8
Is DDT still used today?
Slide9
YES
DDT is still used in some countries for insect control on crops.In countries where mosquitoes carry malaria, DDT is currently used for mosquito control.Slide10
Biomagnification
of DDE in Aquatic Environment
Tertiary Consumer 3-76 µg/g ww(fish eating birds)LevelAmount of DDE in Tissue
Secondary Consumers
1-2
µg/g ww
(large fish)
Primary Consumers
(small fish)
0.2-1.2
µg/g ww
Primary Producers
(algae and aquatic plants)
0.04
µg/g wwSlide11
What kind of damage can DDT cause to birds?Slide12
DDE: Kinds of Damage
Reproductive failure (in birds- eggshell thinning)
Immune system problemsNervous system damageDeathSlide13
High levels of DDE cause the female ospreys to lay eggs with thin eggshells.
Thin eggshells have a greater chance of breaking, leading to embryo death.
With high levels of DDE, female ospreys can also lay eggs that contain high enough concentration of DDE to prevent embryo development. Slide14
How is the impact of DDE on osprey and eagle reproduction measured?Slide15
One Method for Measuring the Impact of DDE on Osprey Reproduction
Collect eggs from abandoned osprey nests.
Measure the thickness of the eggshells.Measure the amount of DDE in the egg.Determine the association between eggshell thickness and DDE residue.Slide16
Visualizing the Data
Slide17
If increased DDE concentrations causes increased eggshell thinning, how would you draw a graph showing the relationship between eggshell thinning and DDE concentration?
Slide18Slide19
If DDE has no impact on eggshell thickness, what relationship would you expect to see between DDE levels and eggshell thickness?
Slide20