Effects of PesticidesDiscuss the effects continually

introducing new pesticides into the environment

Pesticides• All pesticides are toxic to some living thing• Herbicides• Fungicides• Insecticides Synthetic pesticides are lab made and generally take longer to

break down. Due to this they can accumulate in the environment. Natural pesticides tend to break down quicker, and are less harmful to the environment.

Effects on non-target species

• Pesticides have direct or indirect effects on other living things. They do so by;

• Changing food webs• Direct or indirect poisoning• Chemical biomagnification and • habitat changes.

Bioaccumulation

• Accumulation of chemicals in the tissue of organisms

“an increase in the concentration of a chemical in an organism over time compared to the chemicals conc in the environment.”

• Is the net result of a chemicals Uptake…….storage…….elimination

Biomagnification

Is the increase in concentration of a bio-accumulated chemical as it moves through the food web

Example of biomagnification the Bald Eagle was severely affected in

the mid-20th century by a variety of factors, among them thinning of egg shells, attributed to the use of the pesticide DDT. Bald Eagles, like many birds of prey, were especially affected by DDT due to biomagnification. DDT itself was not lethal to the adult bird, but it interfered with the bird's calcium metabolism, making the bird either sterile or unable to lay healthy eggs. Female eagles laid eggs that were too brittle to withstand the weight of a brooding adult, making it nearly impossible to produce young.

Effects on humansDangers of pesticide use. WWF Australia You Tube

Include•Asthma•Skin conditions•Birth defects•Neurological effects•Cancer•Hormone disruptionetc

Prolonged exposure to pesticides in humans can lead to severe disorders in our reproductive, nervous and immune system, also been linked to cancer.

DDT

• Dichlorodiphenyltrichloroethane (DDT) was first synthesised in 1874 but its power as an insecticide was not reported until 1939

DDT

• It is a cheap chemical, highly toxic to insects but with extremely low toxicity to mammals and humans. Was widely used during the 1950s to treat crops