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Pesticide, Bioaccumulation and Biomagnification

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Presentation on theme: "Pesticide, Bioaccumulation and Biomagnification"— Presentation transcript:

1 Pesticide, Bioaccumulation and Biomagnification

2 A. Pesticides A1. Pesticides are chemicals that kill pests
A million tonnes of pesticides used yearly A3. 75% used in agriculture

3 B-Types of pesticides B1. Insecticides: kill insects by attacking their nervous system B2. Herbicides: kill undesirable plants (weeds) B3. Bateriocides: kill bacteria. B4. Fungicides: kill fungi, mold

4 C-Benefits of using pesticides?
C1- Protect, thus protecting industries’ and farmers’ profits C2- Prevent epidemic outbreak Discuss in pair

5 D- Problems with Pesticides
Let’s brainstorm in pairs, with whiteboard

6 D- Problems with Pesticides?
D1. Mutation randomly occur allows pest to develop resistance to pesticides D2. Costs lots of time and resources to constantly develop new poisons D3. They are often toxic substances and can accumulate and magnify in the food chain


You are what you eat!!! FOOD FOR THOUGHT ACTIVITY Due Monday Sep

9 E-Bioaccumulation E1. refers to an increase in the concentration of a chemical in an organism over time.

10 F- Biomagnification (=bioamplification)
F1. Biomagnification is the increase concentration of toxic chemicals, such as pesticides as it is passed upwards and maximized to the top predator of the food chain Bioaccumulation worsens biomagnification

11 TROPHIC LEVEL Trophic level is the position that an organism occupies in a food chain - what it eats, and what eats it.

12 G- Meet a pesticide DDT: (stands for Dichlorodiphenyltrichloroethane)
- First produced in 1939 a highly potent, fat soluble insecticides Tobacco extract (i.e. nicotine sulfate) as insecticides Plants themselves developed chemicals that can kill animals that graze on them a DDT molecule

13 H- Case study 1: DDT and the bald eagle
Bald eagles feed on fish They disappear for many reasons: H1. Loss of habitat (industrialization, deforestation) H2. Hunting H3.Toxins in lake in lake

14 I-DDT in the Great Lakes
I1. How DDT enter the Great Lakes? I2. In this food chain, what type of consumer is the bald eagle? I3. tertiary (top) consumer I4.How could DDT end up in the bald eagle with highest concentration?

15 J-Impacts of DDT on birds
double-crested cormorant DDT was banned in Canada in 1971 Egg shell thinning

16 K-DDT and Human Health K1. Concentration of 6-10 mg/kg leads to such symptoms as headache, nausea, vomiting K2. Lethal (=deadly) dose :236 mg DDT per kg of body weight

17 L-Discussion L1.There still countries haven’t banned DDT. Why would this be of concern to Canadians? L2. Breast milk contains fat. How breast-feeding might affect the concentration of DDT in a mother and in her baby? Throw in questions of scavenger (vulture)

18 M-Recent pesticide development
-Water soluble pesticides -animals can remove them in livers -break down quickly -therefore need to apply them more frequently

19 R- Mercury Poisoning- Minamata disease
Choose the most correct statement(s) The residents of Minamata have bioaccummulated mercury in their body The residents of Minamata have biomagnified mercury in their body The residents of Minamata display both bioaccummulation and biomagnification The residents of Minamata have also suffered from lead poisoning

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