What kind of damage can DDT cause to birds?

1. What kind of damage can DDT cause to birds?

2. 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.

3. DDT: Kinds of Damage • Reproductive failure (in birds- eggshell thinning) • Immune system problems • Nervous system damage • Death

4. How does DDT move into lakes, streams and oceans?

5. 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.

6. Is DDT still used today?

7. 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.

8. What is a Food Web?

9. Food Web=A summary of the feeding relationships within an ecological community. Osprey Sucker Trout Silverside Bay Shrimp Water Plants ORGANIC DEBRIS Plankton

10. Food Chain= One thread of the food web Osprey Large Mouth Bass Crayfish ORGANIC DEBRIS

11. Cast of Food Web Characters • Tertiary Consumers – Animals that eat animals that eat animals • Secondary Consumers – Animals that eat animals that eat plants • Primary Consumers – Animals that eat plants • Primary Producers – Plants and Phytoplankton: organisms using the sun for energy

12. Why is food web knowledge important for understanding the impact of DDT on ospreys and eagles?

13. Ospreys and eagles are tertiary consumersand this makes them particularly vulnerable to DDT because of bioaccumulation and biomagnification.

14. What is bioaccumulation?

15. 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.

16. What is biomagnification?

17. 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

18. Biomagnification of a DDE in Aquatic Environment Amount of DDE in Tissue Level Tertiary Consumer 3-76 µg/g ww (fish eating birds) 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 ww

19. Considering biomagnification, how could DDT harm an osprey?

20. Osprey Food Web DDT Concentration 3-76 µg/g Osprey Large Mouth Bass 1-2 µg/g 0.2- 1.2 µg/g Crayfish Plant material and algae 0.04 µg/g

21. Units of Measurement 1 gram = 1000 milligrams (mg) = 1,000,000micrograms (µg) microgram (µg) = one millionth of a gram To describe concentrations:µg/g = number of micrograms (of toxin) per gram (of tissue) 2 µg/g DDE in egg content means there is 2 parts of DDE in 1,000,000 parts of an egg contents

22. The Effects of DDT on Reproduction • Wiemeyer, S.N. et al., 1984. Organochlorine pesticide, polychlorobiphenyl, and mercury residues in bald eagles, 1969-1979, and their relationship to shell thinning and reproduction. Arch. Environ. Contam. Toxicol., 13, 529. • Johnson, D.R. et al., 1975. DDT and PCB levels in Lake Coeur d’Alene, Idaho osprey eggs, Bull. Environ. Contam. Toxicol., 13, 401.

23. High levels of DDT 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 DDT, female ospreys can also lay eggs that contain high enough concentration of DDT to prevent embryo development.

24. How is the impact of DDT on osprey and eagle reproduction measured?

25. One Method for Measuring the Impact of DDT on Osprey Reproduction • Collect eggs from abandoned osprey nests. • Measure the thickness of the eggshells. • Measure the amount of DDT in the egg. • Determine the association between eggshell thickness and DDT residue.

26. Visualizing the Data

27. If increased DDT concentrations causes increased eggshell thinning, how would you draw a graph showing the relationship between eggshell thinning and DDT concentration?

29. If DDT has no impact on eggshell thickness, what relationship would you expect to see between DDT levels and eggshell thickness?

31. If increased levels of DDT are associated with increased eggshell thickness, how would you make a graph showing the relationship between eggshell thickness and DDT concentration?

33. DDT reduces reproductive rates at moderate concentrations. At high concentrations it causes total reproductive failure. How would you make a graph showing the relationship between DDT concentration and reproductive success?