Week 8: Pest Control and Radiation Flashcards
Give 5 details about the history of pest control.
Pest control old as history (e.g., Book of Exodus locusts)
Paris green (copper acetoarsenite) one of 1st used widely in agriculture (1860s), insecticide, fungicide; lead
arsenate popular late 19th c.
1939 Paul Müller found DDT (dichlorodiphenyltrichloro-
ethane) an effective insecticide; became widely used for vector control (e.g., malaria mosquitoes)
DDT, other chlorinated pesticides changed food
production worldwide; Rachel Carson’s Silent Spring (1962) alerted public to risks associated with their use
Env. and societal cost of pesticide use in U.S. $12 billion
(Pimentel 2009): public health, livestock, pesticide resistance, honeybee/wildlife losses, gov’t expenditures
List the 7 U.S. EA Health Pest categories.
- Cockroaches
- Body, head, and crab lice
- Mosquitoes
- Rats and mice
- Microorganisms (bacteria, viruses, protozoa)
- Reptiles and birds
- Various mammals
Give 6 details about mosquitos and other common insect pests.
Mosquitoes: vector for numerous human diseases
Bedbugs: prefer human blood; hide in mattresses
Fleas: common, can carry plague, murine typhus
Sand flies: leishmaniases
Termites: $ millions in wood damage
Ticks (insect relatives): Lyme disease, many others
Give 7 details about insect repellants.
Insect repellents come in many forms, including aerosols, sprays, liquids, creams, and sticks. Some
are made from chemicals and some have natural ingredients.
DEET is a chemical used in insect repellents. Studies show that products with higher amounts of
DEET protect people longer
The American Academy of Pediatrics (AAP) recommends that repellents should contain no more than 30% DEET when used on children. Insect repellents also are not recommended for children
younger than two months.
The Centers for Disease Control and Prevention (CDC) has also recommended other repellents that
may work as well as DEET, repellents with picaridin and repellents with oil of lemon eucalyptus or 2% soybean oil. Currently these products have a duration of action that is comparable to that of about 10% DEET.
Is DEET safe? Once applied to the skin it is absorbed, in quantities that have ranged between 5% and 15% in different studies (Antwi, Shama, & Peterson, 2008; Osimitz, Murphy, Fell, & Page, 2010).
Acute toxicity is extremely rare; fewer than fifty cases of serious toxic effects have been documented in the medical literature (Fradin & Day, 2002).
Animal testing has suggested that high dose DEET may cause neurological effects (Antwi et al.,
2008).
What are the 4 common pesticide classes? How are they classified?
4 common insecticide classes:
Organophosphates (OPs)
Carbamates (like OPs)
Organochlorines
Pyrethroids
Classified according to target pests, or mode of action
What are 4 details about organophosphates?
Mode of action: inactivate acetylcholinesterase
Unlike DDT/organochlorines, degrade in environment after a few days, acutely toxic (produce cholinergic crisis, can be fatal)
Chronic low-level exposure (e.g., in food, farmworkers) may affect neurological function
Many uses eliminated in U.S. but used globally, poisoning risk
What are 5 details about organochlorine pesticides?
Persistent organic pollutants (POPs): highly lipophilic (fat soluble), stable, mobile, resistant to breakdown
Widely used 1st half 20 c. (DDT, aldrin, dieldrin, heptachlor, chlordane, endosulfan): effective, cheap
Bioconcentrate (animal, human fatty tissues) and biomagnify up food chain; all are exposed to low levels,
especially in high fat foods (meat, dairy, fish, etc.)
Acute human toxicity low but chronic exposure assoc. w/liver, kidney, thyroid, bladder, CNS damage; eggshell thinning, reproductive failure in birds (Silent Spring)
Stockholm Convention on POPs (2004): national OC bans, except in public health emergencies; WHO (2006) now supports use in high malaria regions
Give 1 detail about pyrethroids.
Synthetic version of pyrethrin in chrysanthemums, modified to increase stability; less toxic than OPs; allethrin, permethrin, resmethrin, etc.
Give 5 details about biopesticides.
Derived from natural materials
Microbial pesticides, e.g., Bacillus thuringiensis (Bt)
Plant-incorporated protectants, e.g., GM plants w/ Bt protein
Biochemical pesticides, insect pheromones, interfere w/mating
Botanical pesticides, derived from plants, low toxicity
Give 2 details about herbicides.
Mostly widely used pesticide type agric. and residential sectors
Most used: glyphosate (Roundup), atrazine, 2,4-D, other herbicides and fumigants (methyl bromide, chloropicrin, other
Give 5 details about pesticide exposure and public health concerns.
Residential exposure common (80% U.S. households use pesticides, Damalas & Eleftherohorinos 2011)
Semivolatile pesticides used indoors can vaporize, distribute to non-targeted surfaces, expose children
Occupational exposure common among farmworkers, especially among pesticide sprayers and handlers, workers entering fields after spraying
Unintentional poisonings: workers in agriculture, pet groomers, etc.; ~10,000-20,000 cases/year in U.S. (CDC)
Self-poisonings: pesticides ~1/3 of ~ 1 million suicides/year globally (Gunnell et al. 2007; Wu et al. 2012); especially rural areas in developing countries
Give 6 details about pesticide toxicity categories and labeling requirements.
WHO and EPA have similar classification systems to alter people to the relative danger of different pesticide products;
Toxicity category I: must say “danger” and “poison” if assigned on the basis of oral, inhalation, or dermal toxicity with a skull and crossbones
Toxicity category II: must say “warning”
Toxicity category III: must say “caution”
Toxicity category IV: must say caution
Every pesticide category must have a child hazard warning
What are the 3 U.S. acts that regulate pesticides?
Federal Insecticide, Fungicide, and Rodenticide Act: requirements for pesticide registration, toxicity data submission, labeling, training, restricted handling and use
Federal Food, Drug, and Cosmetic Act of 1938: requires EPA to set health-based tolerances (permissible levels) in food; EPA monitors residues in fruits, vegetables, seafood, USDA monitors meat, poultry, dairy, eggs
Food Quality Protection Act (1996): updated FIFRA and FFDCA mandating single health-based standard in food, to protect infants and children
Give 2 details about global pesticide regulation.
Global (1 in 4 nations lacks laws [Matthews et al. 2011]):
Developing countries use 20% of world’s agrichemicals but account for 99% of pesticide poisonings (use older, more toxic ones, black markets, unsafe storage and handling, etc.)
Explain integrated pest management (6 details).
Developed in 1960s; comprehensive approach using combination of methods (chemical and non-chemical)
Management and cultural practices, e.g., farmers: plant resistant cultivars; public health officials: avoid standing water to control mosquitoes, etc.
Structural maintenance, e.g., screens on vents, fix leaks
Regular pest population monitoring, targeted pesticide use
Control measures: physical/mechanical interventions, biological control agents, use chemicals as a last resort
Consumer education: general public and IPM users, how to reduce pest hazards
Give 5 details about the history and background of radiation.
Early discoveries: Roentgen, X-rays, 1895; Becquerel, radioactivity 1896; Curie coined “radioactivity,” 1898; Rutherford deduced structure of atom (1911);
Theoretical foundations
Radiation- Energy in electromagnetic form
Nucleus of atom packed with protons and neutrons; certain combinations stable; others unstable, spontaneous transformation/disintegration to achieve stable state
As wavelength shortens and frequency increases, more energy released at close range, potentially dangerous to living things
What are 4 details about the sources and protections of extremely low frequency EMFs (non ionizing radiations)?
Thunderstorms, power lines, household appliances, etc.
High exposures - power line workers, welders, etc.
Shock risk, “possibly carcinogenic to humans” (IARC 2012) but mechanistic data limited
Protection: exposure limits for workers and general public
Give 3 details about the sources and protections of microwave and radio frequency radiations (non ionizing radiations)?
Radar, TVs, radios, cell phones/towers, microwave ovens, etc.
Can penetrate deeply, burn dermal and subcutaneous tissue; other potential effects (e.g., DNA damage) but data limited
Protection: proper design/shielding, exposure limits (e.g., 1.6 watts/kg for cell phones, FCC 2015) based on specific absorption rate (radiofrequency energy absorbed in tissue)
Give examples and protections from non ionizing radiations (visible light and ultraviolet).
Visible light:
sun, lasers, electric welding/carbon arcs, tungsten lamps
too much: retinal injury; too little, eyestrain
protection: engineering controls, training, PPE
Ultraviolet (UVA, UVB, UVC)
sun, sunlamps/tanning/black light lamps, welding arcs, Hg vapor lamps, hot-metal operations, lasers
too much: burns, damage to skin and eyes; too little, vitamin D deficiency;
UVB in particular associated with sunburn and skin cancer
protection: engineering, administrative controls for workers; limit exposure, protection (windows, clothing, sunscreen, sunglasses) for general public
What are 3 details about the basics of ionizing radiation?
X-, gamma, cosmic rays - energy that breaks bonds
Directly ionizing particles (ionize by collision): protons, alpha particles, beta particles, electrons (sometimes)
Indirectly (only energy to liberate directly ionizing particles)
What are 3 details about natural sources of ionizing radiation?
Cosmic rays: hit Earth’s atmosphere, interact w/atoms to form particles; higher doses at higher latitudes/elevations
Terrestrial: radioactive minerals in Earth’s crust (e.g., K, thorium, uranium); doses vary geographically; radon, from decay of radium to radioactive gas, which decays to radioactive particles - accumulate in basements, etc.; inhaled radon decay products comprise >2/3rds of
Natural background radiation dose internal emitters: naturally radioactive K inside body
What are 3 details about human made sources of ionizing radiation?
Consumer products, food: small amounts, various products
Medicine: diagnostic X-rays, interventional & nuclear medicine
Accidents: highest exposures from Chernobyl (1986)
Give human health effects of acute, carcinogenic, and developing embryos.
Acute:
Exposure to > 10 Gy, fatal to all, with or w/out treatment
Lower exposures, acute effects to radiosensitive tissues, e.g., skin, bone marrow/lymphoid tissue, intestine, gonads, respiratory tract, eye lens
Whole body (radiation sickness) vs. localized radiation injury
Carcinogenic:
Epi. evidence: skin cancer, leukemia in early radiation workers; osteosarcomas, cranial tissue sarcomas in radium dial painters; respiratory carcinomas in underground hard rock miners; other: atomic bomb survivors, radiotherapy patients, people living
downwind of nuclear test and accident sites
Developing embryo:
Susceptible during pre-implantation, organogenesis
Carcinogenic, other effects (e.g., dose-dependent IQ loss)
Give 3 details about radiation protection.
Internal: engineering controls, protective measures (e.g., confinement of contaminated air, preventing ingestion, dermal contact); PPE as last resort
External: #1, eliminate source; then engineering controls to minimize exposure time, maximize distance from source, source shielding
Exposure to be kept ALARA (as low as reasonably achievable)
Give 4 details about risk assessment of low-level irradiation.
Numerous dose-effect models of radiated populations
Most assume increasing risk with increasing dose
Help establish dose limits for workers, general public
Children, people with certain hereditary disorders appear more susceptible to certain types of cancer
