please read carefully ..

Biology 140 Instructor: Dr. Franklin Quarcoo

Office Location: 115 Henderson Hall Phone: 727-8792

Office Hours: MWF 3.00 – 5.00 pm Email: [email protected]

¨ Pests (in Part 1) ¨ Pesticides ¡ Benefits (in Part 1) ¡ Problems (some in Part 1) ¡ Categories ¡ Chemical types ¡ Regulation of Pestitcides

¨ Alternatives to Pesticides ¨ Reducing Pesticide Exposure

¨ Effects on non-target species (in Part 1) ¨ Pesticide resistance and pest resurgence

(in Part 1) ¨ Creation of new pests (in Part 1) ¨ Concentration in food chains ¨ Persistence and mobility in the environment ¨ Human health problems

¨ Bioaccumulation: ¡ Occurs in individual organisms. ¡ Many pesticides are fat-soluble. ¡ Small, harmless amounts of pesticide ingested . ¡ Pesticides bind with body fats (lipids). ¡ Pesticide not excreted or broken down. ¡ Over time pesticide builds up to high levels in

body -- higher than what is in it’s food source = bioaccumulation.

¡ May or may not reach toxic levels..

¨ Biomagnification ¡ Occurs in food chains. ¡ Each organism in food chain concentrates

pesticide in its body through bioaccumlation. ¡ Next organism up the food chain has more

contaminated food; concentrates pesticide to a greater level.

¡ Concentration of pesticide in organisms increases as you move up the food chain = biomagnification.

¡ Top carnivores most susceptible to pesticide poisoning..

¨ DDT = dichloro-diphenyl-trichloroethane. ¨ 1874 -- first synthesized by Othmar Zeidler ¨ 1939 -- Paul Müller discovered insecticidal

properties of DDT. ¨ 1943 -- DDT marketed as first commercial

synthetic pesticide. ¨ Highly toxic to insects, but relatively non-toxic

to humans. ¨ Heavily used in 1940s and 1950s on crops,

livestock, homes and people. ¨ Very effective in controlling insect pests. ¨ 1948 -- Müller wins Nobel prize..

¨ DDT very persistent -- half life in soil of decades.

¨ Biomagnifies in food chains. ¨ High concentrations in top predator birds

(eagles, hawks, falcons, pelicans). ¨ Inhibits deposition of calcium carbonate in

eggshells. ¨ Thinner eggshells break easily -- reduced

reproduction. ¡ Bald eagles reduced to about 400 pairs (lower 48

states). ¡ Peregrine falcons reduced to 120 birds (lower 48

states)..

DDT Use

¨ 1962 -- Rachel Carson wrote Silent Spring. ¨ Book described harmful effects of pesticides

on environment, especially birds. ¨ Helped trigger start of environmental

movement. ¨ 1972 -- DDT banned in U.S. ¨ Now banned world-wide for agricultural use. ¨ But still allowed for use for control of disease

vectors in tropical countries (e.g. mosquitoes for malaria control)..

¨ Banning of DDT and other chlorinated hydrocarbons has led to recovery of populations of top predator birds.

¨ Peregrine falcons have recovered from 120 to 1400 birds (lower 48 states).

¨ Bald eagles have recovered from 400 to 9800 pairs (lower 48 states).

¨ Both birds were removed from the endangered species list in 1994..

DDT

¨ Some pesticides persist for decades before breaking down.

¨ Persistent pesticides move by wind, water and animals far from original application site.

¨ Pesticides tend to evaporate in warm areas and accumulate in polar regions.

¨ Inuits of northern Canada have highest levels of pesticide residues of any human population.

¨ Inuit breast milk contains 5 times as much pesticide residues as the breast milk of women from Canada’s industrial cities to the south.. ICA

¨ In the food chain: Plankton --> Fish --> Seal -- > Killer Whale, the greatest concentration of pesticide residue is expected in the Killer Whale. This is due to the process of:

¨ (a) Bioaccumulation ¨ (b) Biomagnification ¨ (c) Biomass accumulation ¨ (d) Biopersistence and Mobility ¨ (e) Bioremediation

¨ In the food chain: Plankton --> Fish --> Seal -- > Killer Whale, the greatest concentration of pesticide residue is expected in the Killer Whale. This is due to the process of:

¨ (a) Bioaccumulation ¨ (b) Biomagnification ¨ (c) Biomass accumulation ¨ (d) Biopersistence ¨ (e) Bioremediation

¨ Acute effects: ¡ Short-term illness. ¡ One or a few exposures (often accidental). ¡ High doses.

¨ Chronic effects: ¡ Long-term illness. ¡ Repeated exposure. ¡ Low-level doses. ¡ Cancer, sterility, birth defects, neurological

problems, immune system problems, Parkinson’s disease..

¨ Acute poisoning (WHO and EPA): ¡ 3 million cases of acute poisoning per year (300,000 in

U.S.). ¡ 18,000 deaths per year (25 in U.S.). ¡ Highest risk = agricultural workers, children. ¡ In U.S., 250,000 people per year become ill from

household pesticides (bait boxes, pest strips, bug bombs, flea collars, pesticide pet shampoos, week killers)..

¨ Chronic Poisoning: ¡ Hard to separate pesticides from other causes. ¡ Estimates of 2,000-10,000 premature deaths per year

due to legal pesticide residues in food..

¨ Mothers who ate lake Michigan fish (high levels of PCBs) regularly had children with learning and attention problems (lower IQ scores, below average reading, poor memory).

¨ Missouri children from homes with “no-pest strips” had higher rates of leukemia and brain cancer than similar children from home without “no-pest strips”..

¨ Foothill ranches: ¡ Low pesticide use.

¨ Valley ranches: ¡ High pesticide use.

¨ Valley children: ¡ Decreased memory, physical stamina, hand-eye

coordination; greater irritability..

Low Pesticide

Use

High Pesticide

Use ¨ Insecticides kill insects ¨ Herbicides kill plants ¨ Fungicides kill fungi ¨ Rodenticides kill rodents ¨ Miticides kill mites ¨ Nematocides kill nematodes (roundworms)

¨ Inorganic ¨ Botanicals ¨ Chlorinated hydrocarbons (organochlorides) ¨ Organophosphates ¨ Carbamates ¨ Pyrethroids

¨ First pesticides: ¡ ~3000 BC -- Sumarians -- sulfur (insects, mites) ¡ ~500 BC -- China -- arsenic, mercury (body lice) ¡ ~1400 AD -- arsenic, lead, mercury applied to crops ¡ ~1920 -- most use discontinued due to increasing

fatalities and poisonings. ¨ Currently-used inorganic insecticides: ¡ Boric acid (roaches). ¡ Lime sulfur (tree spray for bacteria, fungi, insects)..

¨ Extracted from plants. ¨ Plants’ natural defenses against insects. ¨ Commonly used before 1940 (when synthetic

pesticides were first developed). ¨ Examples: pyrethrum (chrysanthemum),

nicotene (tobacco), rotenone..

¨ Also called organochlorides. ¨ First synthetic pesticides. ¨ Kills by disrupting signal transmission along

nerve cells. ¨ Widely used from 1940s into 1970s. ¨ Many now banned; few still used today. ¨ Toxicity to mammals: relatively low. ¨ Persistence: high (years); biomagnified in food

chains. ¨ Examples: DDT, toxaphene, dieldrin,

chlordane, lindane, mirex, paradichlorobenzene (mothballs)..

¨ Similar to nerve gas. ¨ Highly toxic, but short-lived. ¨ Kills by blocking signal transmission between

nerve cells. ¨ Toxicity to mammals: high ¨ Persistence: low (days). ¨ Examples: malathion, parathion, diazinon..

¨ Kills by blocking signal transmission between nerve cells.

¨ Toxicity to mammals: moderate. ¨ Persistence: low (days). ¨ Examples: carbaryl (Sevin), aldicarb (Temik)..

¨ Synthetics based on pyrethrum (botanical). ¨ Fastest developing group. ¨ Very effective and safe. ¨ Kills by disrupting signal transmission along

nerve cells. ¨ Toxicity to mammals: low. ¨ Persistence: low (days). ¨ Examples: allethrin (Raid), bifenthrin..

ICA

¨ The first group of synthetic pesticides that was widely used was:

¨ (a) Botanicals ¨ (b) Chlorinated hydrocarbons ¨ (c) Inorganic compounds ¨ (d) Organophosphates ¨ (e) Pyrethroids

¨ The first group of synthetic pesticides that was widely used was:

¨ (a) Botanicals ¨ (b) Chlorinated hydrocarbons ¨ (c) Inorganic compounds ¨ (d) Organophosphates ¨ (e) Pyrethroids

¨ Which group of insecticides has the highest toxicity to mammals?

¨ (a) Carbamates ¨ (b) Chlorinated hydrocarbons ¨ (c) Organophosphates ¨ (d) Pyrethroids

¨ Which group of insecticides has the highest toxicity to mammals?

¨ (a) Carbamates ¨ (b) Chlorinated hydrocarbons ¨ (c) Organophosphates ¨ (d) Pyrethroids