1. Toxicology of Animals in the Wild

2. Effects of DDT Invertebrates Fish Birds Mammals
(Dichlorodiphenyltrichloroethane)
Invertebrates
Fish
Birds
Mammals

3. Terrestrial Invertebrates
Mollusks & Earthworms
Are not affected very much by DDT
Can be tolerated for a long period of time
Will be retained in their bodies which will lead to biomagnification

4. Aquatic Invertebrates
Very sensitive to DDT
Reproductive / development impairment
Nervous system disorders
Used one as a sea crustacean control because it’s so effective against aquatic invertebrates

5. Biomagnification: Increase in concentration of a pollutant from one link in a food chain to another
PPM: Parts Per Million:A unit of concentration often used when measuring levels of pollutants in air, water, body fluids, etc. One ppm is 1 part in 1,000,000. The common unit mg/liter is equal to ppm. Four drops of ink in a 55-gallon barrel of water would produce an "ink concentration" of 1 ppm.

6. Biomagnification

7. Fish
DDT causes many problems in fish (So many, in fact, that it has been difficult to study DDT in fish. We can't seem to find where the DDT is doing the most damage.)
Probably involves DDT's presence in the fish's plasma membrane, an area where important biological processes are occuring
There are a few trends that we've noticed with DDT and fish. Smaller fish are usually more sensitive, and for same species of fish, DDT becomes less toxic at higher water temperatures

8. Birds
DDT is most famous for its effect on birds. Some research have shown that for certain species, DDT causes the thinning of eggshells Some species affected by DDT:
osprey
eagles
pelicans
falcons
hawks

9. Eggshell Thinning
DDT can change into many different forms that are only slightly different from the original. We call these new forms metabolites. We think that one of these metabolites, abbreviated DDE, interferes with certain reproductive enzymes in birds
Enzymes act as helpers for certain chemical reaction. They can speed up biological processes, slow them down, etc.. In birds, certain reproductive enzymes affect how much calcium is deposited in eggshells. DDE probably gets in the way of some of these enzymes. Consequently, eggshells have less calcium, which makes them easier to break

10. Mammals In the past, we have used DDT to control mice, rats, and bats
Bats are especially sensitive to DDT. Very low doses of DDT can affect them severely
Current research deals with DDT's effects on larger mammals

11. How DDT Kills
The plasma membrane is made up mostly of lipids (fats). Remember that DDT is fat soluble, and so it will dissolve easily into the plasma membrane. In order to get into the plasma membrane, the DDT must open up the membrane slightly to make room for itself. DDT, unfortunately, opens up the membrane a little too much and causes the cell to leak.
Two things which will slip through these leaks are sodium ions and potassium ions.

12. Environmental Estrogens
Endocrine-disruptors
Endocrine-modulators
Ecoestrogens
Environmental hormones
Xenoestrogens
Hormone-related toxicants
Endocrine-active compounds
Phytoestrogens

13. Endocrine Distributors
Synthetic chemicals and natural plant compounds that may affect the endocrine system (the communication system of glands, hormones and cellular receptors that control the body's internal functions)
Many of these substances have been associated with developmental, reproductive and other health problems in wildlife and laboratory animals

14. Substances can:
Mimic or partly mimic the sex steroid hormones estrogens and androgens (the male sex hormone) by binding to hormone receptors or influencing cell signaling pathways. Those that act like estrogen are called environmental estrogens.
Modify the making and function of hormone receptors.
Block, prevent and alter hormonal binding to hormone receptors or influencing cell signaling pathways. Chemicals that block or antagonize hormones are labeled anti-estrogens or anti-androgens.
Alter production and breakdown of natural hormones.

15. Effects of EE
Male fish living near municipal sewage outlets in England had both male and female sex characteristics and their livers produced vitellogenin, a female egg-yolk protein not normally found in males
cancers of the female and male reproductive tract
malformed Fallopian tubes, uterus and cervix
altered bone density and structure
abnormal blood hormone levels
reduced fertility
altered sexual behavior
modified immune system

16. Chemicals Related to Deformations
Aldrin
Chlordane
Endrin
Heptachlor
Mirex
Toxaphene
Hexachlorobenzene (HCB)
Polychlorinated biphenyls (PCBs)
Dioxins and Furans
Environmental Estrogens

17. Chemical Facts
60 million birds are killed annually by legal pesticide use in the US
60% of herbicides (by poundage) used in the US are endocrine disruptors
In 1996, 20,000 Swainson's hawks overwintering in Argentina were killed by the pesticide monocrotophos
Male fish in the UK and US are producing egg-yolk material at levels that only females should be producing

18. Main Contributors of Defromities

19. Persistent Organic Pollutants (POPs)
Toxic substances composed of organic (carbon-based) chemical compounds and mixtures. They include industrial chemicals like PCBs and pesticides like DDT. They are primarily products and by-products from industrial processes, chemical manufacturing and resulting wastes.

20. POPs Today
These pollutants are persistent in the environment and have the ability to travel through air and water to regions far from their original source. POPs also tend to bioaccumulate, meaning they accumulate in fatty tissue of organisms and dramatically increase in concentration as they move up the food chain.

21. Pesticides and Biodiversity
Biodiversity is threatened by pesticides in several ways. First, when pesticides reduce species diversity and population size. Secondly, non-target species can be affected when pesticides are passed on through the food chain: for example, predators ingest toxic residues in the bodies of their prey. Non-target species may also be affected indirectly, when pesticides limit the quantity and quality of food and habitat. For example, herbicides can eliminate plants and weeds which are an important food source for many birds and mammals. Reducing the abundance of plants, pollinators, insects, and fungi results in decreasing numbers of other species.

22. As agriculture has become more specialized, mechanized and commercial, crops have become more genetically homogeneous.
To guarantee continuous, high level production, farmers must eliminate pests quickly and at minimum cost - so we have looked to chemical controls.
Chemical controls are imperfect and have changed pest evolution (diversity) to produce resistant bugs and diseases, intensifying the need for stronger pesticides.

23. Principal Problems of Pesticides
Inherited resistance - the strongest pests survive, become immune.
Genetic imbalance - predators and useful insects are killed and pests can rebound subsequently.
Bioaccumulation - they are magnified up the food chain leading to mutations, cancer, etc.
Non-point source pollution - they run off or seep into groundwater affecting aquatic ecology and drinking water quality.
Risk of accidents and local effects - production accidents (Bhopal), drift from fields to schools (Hollister, Fresno).

25. Aflatoxins (A principal mycotoxin)
Aspergillus flavus
A. parasiticus
B1, B2, G1, G2
AFB1, AFB2

26. What are Aflatoxins
A group of secondary metabolites that are cancer-causing byproducts of a mold that grows on nuts and grains, particularly peanuts. Although aflatoxin is most commonly produced when the potentially affected foods are improperly stored, recent studies have documented its production in the field, particularly if severe climatic changes occur or if the plants are attacked by insects. However, many of these products are used in animal feed, and if an animal consumes infected food, the aflatoxin passes to people in contaminated milk and meat products. Aflatoxin is a carcinogenic for certain animals, particularly cattle

27. Signs of Aflatoxins
Clinical signs of aflatoxicosis in animals include gastrointestinal dysfunction, reduced reproductivity, reduced feed utilization and efficiency , anemia, and jaundice

28. Effects of Aflatoxins Aflatoxicosis is primarily a hepatic disease
The susceptibility of individual animals to aflatoxins varies considerably depending on species, age, sex, and nutrition
Aflatoxins cause liver damage, decreased milk and egg production, recurrent infection as a result of immunity suppression (eg. salmonellosis)

29. B1, M1, G1
Aflatoxin B1, aflatoxin M1, and aflatoxin G1 have been shown to cause various types of cancer in different animal species. However, only aflatoxin B1 is considered by the International Agency for Research on Cancer (IARC) as having produced sufficient evidence of carcinogenicity in experimental animals to be identified as a carcinogen.