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Engineering inputs: pesticides and herbicides. First generation pesticides Arsenic, hydrogen cyanide. Many of these were abandoned because they were ineffective and/or too toxic to humans S econd generation pesticides Developed for WWII and used as part of the Green Revolution. POPs.
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Engineering inputs: pesticides and herbicides • First generation pesticides • Arsenic, hydrogen cyanide. Many of these were abandoned because they were ineffective and/or too toxic to humans • Second generation pesticides • Developed for WWII and used as part of the Green Revolution
POPs • Killed pests and boosted food production • Remain intact in the environment for long periods • Become widely distributed geographically, accumulate in the fatty tissue of humans and wildlife • Have harmful impacts on human health or on the environment. • Aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene
DDT: a second generation pesticide • Effectiveness discovered in 1930's • Persistent and versatile • Fatal on contact in extremely minute quantities to wide range of insects, less acutely toxic to humans • Pervasive damage began to be recognized in late 1950’s. • Publication of Rachel Carson’s book “Silent Spring” in 1962 galvanized public support for better regulation of pesticides
DDT and the environment • DDT bioaccumulates and can be highly concentrated in the tissues of organisms high on the trophic pyramid • Bird populations declined because DDE (a breakdown product of DDT) interferes with calcium metabolism. Eggs were thin-shelled and young did not hatch. Eggshell thickness Year 1947
DDT and the environment • Phased out by EPA in 1970’s • By 2004, over 100 nations had signed an international treaty, the Stockholm Convention on Persistent Organic Pollutants , which aims to phase out Persistent Organic Pollutants (POPs), including DDT. • As of 2011, 176 nations were parties to this convention; the US is not a party to this convention.
DDT in the developing world • Last DDT manufacturing plant in the US was dismantled in 1983 and sold to Indonesia, where it continued to manufacture DDT until Indonesia ratified the Stockholm Convention in 2009 • Approximately 17 developing countries, however, continue to use DDT
DDT and public health • DDT is inexpensive and accessible defense against malaria-transmitting mosquitoes. • Death toll from malaria approximately 1 million or more people each year • Chemical control being replaced by bed nets, antimalarial prophylactics, and reduction of mosquito breeding habitats around humans
The need for a second Green Revolution? • Two billion more people coming to dinner by 2050
Third generation pesticides and herbicides • GMOs and transgenic crops • Inserting genes from other organisms into plants through recombinant DNA technology. • Crops contain genes to produce pesticides needed to repel pests • Genes are also engineered to produce resistance to weed killers
Use of GMO crops increasing globally • Chiefly monoculture crops like corn, soybeans, canola Millions of hectares
Bt Corn • Bacillus thuringiensis, a naturally occurring soil bacteria produces a protein that repels insects • Gene that produces this protein spliced into DNA of corn to make it repel moth larvae of the European corn borer and other pests.
Cons of GMOs • Organic and subsistence farmers will increase dependence upon technology and the consumerism around transgenic crops • Non-target organisms may be effected by pesticides • Concern over genetic pollution and creation of superweeds • Pests develop resistance to the toxins produced by a GMO plant
Terminator seeds • Genetic use restriction technology (GURT) • Plants do not produce seeds that can be planted to grow more individuals
Pros of GMOs • Decreased application of pesticides and herbicides • Targeted efficiency • Resistance to pesticides produced by GMOs have been found, and genes that provide resistance to herbicides have been found in other plants – but impacts are minimal • Incorporation of medicines and vitamins into crops
Great Yellow Hype or Lifesaver? • Critics of golden rice refer to its as the Great Yellow Hype. • In this view, golden rice is Trojan horse for the biotechnology industry • However, supports say it could save millions of lives and prevent unneccesary blindness
GMO…OMG!! • Its not natural, its Frankenfood • Profits go to agribusiness • Patenting of nature is a dangerous precedent • Critics of GMOs invoke the Precautionary Principle
GMO, WC and NVM. • All of nature are GMOs • Lateral gene transfer in bacteria • Incorporation of bacterial and viral genomes in our DNA, the microbiome • Broad scientific consensus is that GMOs are not inherently more risky than other crops
Citrus greening • GMO orange tree • No orange juice (or very expensive) • Orange juice advertised as 100% natural • “The public will never drink G.M.O. orange juice” • “The public is already eating tons of G.M.O.’s,” • “This isn’t like a bag of Doritos”
Not all industrial food is evil • Local is better, but this view can become fetishized • Appeals to a romanticized rural past not tenable for the entire population of Earth • Mix of agricultural types necessary for different circumstances that arise