Envir Health - Chapter 7

Pyrethroids

manufactured chemicals that have a composition similar to pyrethrins. Synthetic.

Dioxins

A family of chemical compounds that are unintentional byproducts of certain industrial, non-industrial and natural processes usually involving combustion. "dioxin" usually means the chemical TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) which is the most toxic forms of dioxin.

Who is at risk for pesticide exposure?

Agricultural workers, animals, pets, children, livestock, and sensitive subpopulations (e.g. pregnant women)

Methyl Isocyanate (MIC)

An intermediate chemical used for the manufacture of carbamate pesticides. It is created as metam sodium breaks down.

Pesticide

Any substance or mixture of substances intended for preventing, destroying, repelling or mitigating pests. Pests can be insects, rodents, weeds, and a host of other unwanted organisms. Also, any substance or mixture intended for use as a plant regulator, defoliant, or dessicant.

Carbamates

Approved for controlling garden pests (e.g. wasps, hornets, and snails) An ingredient in some products applied to furry pets to control ticks and fleas

What are examples of Herbicides/defoliants?

Atrazine, paraquat, and AGENT ORANGE (2,3-D and 2,4,5-T).

Examples of some volatile organic compounds?

Benzene, toluene, methylene chloride, and methyl chloroform

What human activities produce dioxins?

Burning of tobacco gives rise to minute amounts of dioxin in cigarette smoke.

Agent Orange

Called agent orange because they were used in Vietnam during war (Operation Ranch hand). Applied by US to enemies to prevent the thick jungle from concealing them.

Organophosphate Pesticides (Anticholinesterases)

Can be used to control a wide range of insects, thus eliminating the need for multiple applications of different pesticides. They are related to nerve gases (e.g. sarins, soman, and tabun) Disrupt the transmission of nerve impulses. It reduce cholinesterase ability to regulate Ach. Examples: diazinon, malathion, parathion

What are two carbon containing inorganic compounds?

Carbon dioxide and carbon monoxide

What is the product of incomplete combustion?

Carbon monoxide

Examples of Carbamates

Carbyl (Sevin), Aldicarb, Fenoxycarb, Propoxur (used for bed bugs, but banned), and metam sodium

What are examples of organochlorines?

DDT, Lindane (used for lice), chlordane, Mirex, hexachlorobenzene, and methoxychlor.

Organochlorines

Derived from chlorinated hydrocarbons Assoc with suppression of the immune system and cancer Characteristically stable and fat-soluble

DDT

Dichlorodiphenyltrichloroethane; banned from the U.S. in 1972. Due to concerns about possible adverse effects upon the health of humans and wildlife

What does agent orange contain small amounts of?

Dioxins that originated from manufacture of the herbicide. They are carcinogenic, teratogenic

Spill in Sacramento River

Due to trail derailing and spilling metam sodium, eradicating aquatic life

Volatile Organic Compounds (VOCs)

Evaporate readily into the air

DDT is highly toxic

False

What natural events produce dioxins?

Forest fires and volcanic eruptions. Called "natural background" dioxins.

Polycyclic Aromatic Hydrocarbon (PAHs)

Formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charboiled meats

Paraquat

Herbicide; was applied to marijuana plants. Can contaminate and cause lung damage.

Where does DDT concentrates in the body?

In adipose (fatty) tissues

What are the major classes of pesticides?

Insecticides, herbicides, rodenticides, and fungicides.

Two common uses of Polychlorinated Biphenyls (PCBs)?

Insulating fluid in transformers and capacitors and as a lubricant. Use was terminated in 1977.

Organophosphate-induced delayed polyneuropathy (irreversible)

Manifested by numbness, loss of sensory abilities, and weakness.

Organic chemicals

Naturally occurring substances containing carbon, hydrogen, nitrogen, and oxygen (e.g. table sugar)

MIC release in Bhopal, India

Occurred in 1984; accidental release of MIC during an industrial accident. It killed more than 3,800 people.

What are the four major classes of pesticides and insecticides derived from organic chemicals?

Organophosphates (OPs), organocarbamates (carbamates), organochlorides (a.k.a organochlorines), and Pyrethroids.

Contrast insecticides with pesticides.

Pesticides are a broader category. Insecticides are pesticide compounds that are used specifically to control insects.

Biopesticides

Pesticides derived from natural materials like animals, plants, bacteria, and certain minerals Ex. microbial pesiticides, plant incorp protectants, and biochemical pesticides

Where can you find hydrocarbons?

Petroleum, natural gas, coal, and bitumens.

Pyrethrins

Refers to an organic insecticide obtained from naturally occurring sources (or botanicals); have low toxicity Come from natural sources -- certain varieties of chrysanthemum flowers Have great ability to paralyze and kill flying insects Interfere with transmission of neural impulses via action on SODIUM CHANNELS

Example of solvents

Tetrachloroethylene (dry cleaning), trichloroethane, trichloroethylene, toluene, acetone, and benzene.

What was DDT once used for?

To control insects and harmful mosquitoes that carry malaria. Once credited with saving millions of people from death due to malaria.

Persistent Organic Pollutants (POPs)

Toxic chemicals that adversely affect human health and environment around the world. An example would be the pesticide DDT

PCBs are possible human carcinogens

True

Some countries still use DDT

True

Agent orange is associated with several forms of cancer.

True (e.g. soft tissue sarcoma, non-Hodgkin's lymphoma, Hodgkin's disease, and chronic lymphocytic leukemia)

Pyrethrin insecticides have low concentrations of active ingredient

True. As a result, it's used inside the home in aerosol cans, insecticide bombs, insecticidal pet shampoos, treatments for lice applied directly to humans, and mosquito repellents.

Metam sodium is a common soil fumigant.

True. It is one of the pesticides used most frequently in the United States.

DDT has a long half life

True; 10 years

PCBs tend to persist in the environment for a very long time, and tend to bioaccumulate in fish and other animals used for food

True; hence they can impact human health

Dioxins are stable, persistent, and bioaccumulate within the food chain

True; take years to break down

Children appear to be more prone to pesticide poisoning than adults because kids have large skin-surface to body-mass ratios.

True; they also have personal hygiene deficiences

Atrazine

Weed killer. When applied on field crops, runoff from irrigation and rainfall may carry this herbicide into waterways.

Organic solvent

a liquid substance capable of dissolving other substances; the solvent does not change in forming a solution