Pesticides

Overview V0nSVU&feature=related V0nSVU&feature=related V0nSVU&feature=related V0nSVU&feature=related

What Are Pesticides? Chemicals designed and used to kill “pests” (as defined by humans) Chemicals designed and used to kill “pests” (as defined by humans) These chemicals are hard to get rid of and cycle through ecosystems These chemicals are hard to get rid of and cycle through ecosystems

Types of Pesticides Early pesticides included arsenic, lead, mercury, and plant extracts (such as nicotine). Early pesticides included arsenic, lead, mercury, and plant extracts (such as nicotine). In the early 20 th century, we started manufacturing synthetic chemicals, such as DDT. In the early 20 th century, we started manufacturing synthetic chemicals, such as DDT. The more organisms that were considered “pests” to humans, the more we created different pesticides. The more organisms that were considered “pests” to humans, the more we created different pesticides.

Types of Pesticides Pesticide Type Target Pest InsecticideInsects HerbicideWeeds Fungicide Moulds, Mildew, and Fungi BactericideBacteria

Forms of Pesticides Taken many forms, such as sprays, lotions, powders, pet collars, kitchen, laundry, and bathroom disinfectants and sanitizers, swimming pool chemicals… Taken many forms, such as sprays, lotions, powders, pet collars, kitchen, laundry, and bathroom disinfectants and sanitizers, swimming pool chemicals…

Pesticides in Africa TP3Wk&feature=related TP3Wk&feature=related TP3Wk&feature=related TP3Wk&feature=related

Why Use Pesticides? Protect crops from weeds, insects and moulds Protect crops from weeds, insects and moulds Prevent disease (eg West Nile Virus and Malaria) Prevent disease (eg West Nile Virus and Malaria) Cosmetic reasons (lawns and golf courses) Cosmetic reasons (lawns and golf courses)

Bioamplification Is the increase of concentration of a substance that occurs in a food chain as a consequence of: Is the increase of concentration of a substance that occurs in a food chain as a consequence of: –Persistence (can’t be broken down by environmental processes) –Low rate of internal degredation –Low rate of excretion of the substance

Bioamplification Occurs Because: Consumers ingest toxic prey Consumers ingest toxic prey The concentration of the pesticide increases the higher up the food chain The concentration of the pesticide increases the higher up the food chainRESULT: The more trophic levels in a food web, the greater the amplification of the pesticide toxin

Mercury in Our Fish C8Lldk&feature=related C8Lldk&feature=related C8Lldk&feature=related C8Lldk&feature=related

dichlorodiphenyltrichloroethane (DDT) DDT was banned in North America in the 1970’s, but it is still used in many developing countries in the world. DDT was banned in North America in the 1970’s, but it is still used in many developing countries in the world. Newer pesticides are somewhat safer: Newer pesticides are somewhat safer: –Water-soluble – can be excreted and broken down in soil –Less bioamplification BUT BUT –More doses needed to be effective –Not selective – will kill/harm anything

Pesticide Resistance gNS54 gNS54 gNS54 gNS54

Pesticide Resistance Organisms can adat to changes and/or threats in order to ensure their survival. Organisms can adat to changes and/or threats in order to ensure their survival. Pests have developed a resistance to pesticides. Pests have developed a resistance to pesticides. The surviving pests pass those resistant genes on to their offspring, and soon the entire population is resistant to the pesticides. The surviving pests pass those resistant genes on to their offspring, and soon the entire population is resistant to the pesticides. New pesticides have to be created New pesticides have to be created With each ne pesticide, resistant pests will survive With each ne pesticide, resistant pests will survive

Pesticide Movement in Ecosystems Not only do pesticides travel through an ecosystem by the biotic factors, but by abiotic factors as well. Not only do pesticides travel through an ecosystem by the biotic factors, but by abiotic factors as well.

Environmental Law It is interesting that we humans seem to only stop using pesticides when they affect or pose a threat to us. It is interesting that we humans seem to only stop using pesticides when they affect or pose a threat to us. We are finally now seeing laws put into place in Ontario prohibiting the purchase of cosmetic pesticides We are finally now seeing laws put into place in Ontario prohibiting the purchase of cosmetic pesticides