Pesticide, Bioaccumulation and Biomagnification

A. Pesticides

A1. Pesticides are chemicals that kill pests

A2. 2.3 million tonnes of pesticides used yearly

A3. 75% used in agriculture

B-Types of pesticidesB1. Insecticides: kill insects by attacking their

nervous system

B2. Herbicides: kill undesirableplants (weeds)

B3. Bateriocides: kill bacteria.

B4. Fungicides: kill fungi, mold

C-Benefits of using pesticides?

C1- Protect, thus protecting industries’ and farmers’ profits

C2- Prevent epidemic outbreak

D- Problems with PesticidesLet’s brainstorm in pairs, with whiteboard

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 THOUGHTACTIVITY

Due Monday Sep 29 2014

E1. refers to an increase in the concentration of a chemical in an organism over time.

E-Bioaccumulation

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

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

TROPHIC LEVEL

G- Meet a pesticide

a DDT molecule

DDT:(stands for

Dichlorodiphenyltrichloroethane) 

- First produced in 1939-a highly potent, fat soluble insecticides

H- Case study 1: DDT and the bald eagle

Bald eagles feed on fishThey disappear for many reasons:H1. Loss of habitat (industrialization, deforestation)H2. HuntingH3.Toxins in lakein lake

I-DDT in the Great LakesI1. How DDT enter the Great Lakes?I2. In this food chain, what type of consumer is the bald eagle? I3. tertiary (top) consumerI4.How could DDT end up in the bald eagle with highest concentration?

J-Impacts of DDT on birds

double-crested cormorant

Egg shell thinning

DDT was banned in Canada in 1971

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

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?

M-Recent pesticide development

-Water soluble pesticides

-animals can remove them in livers

-break down quickly

-therefore need to apply them more frequently

R- Mercury Poisoning- Minamata diseasehttps://www.youtube.com/watch?v=oxB_SXbxY28

Choose the most correct statement(s)

a.The residents of Minamata have bioaccummulated mercury in their body

b.The residents of Minamata have biomagnified mercury in their body

c.The residents of Minamata display both bioaccummulation and biomagnification

d.The residents of Minamata have also suffered from lead poisoning