Organics Flashcards

1
Q

What are organic toxicants?

A

Carbon based compounds

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2
Q

Petroleum hydrocarbons (PHC)

A

Crude oil - unrefined, make of aromatic and aliphatic compounds of chains from C5 - C50, highly lipophlic

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3
Q

What is fraction 1 PHC used for?

A

Volatile fraction used for gasoline

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4
Q

What is fraction 2 PHC used for?

A

To produce kerosene, creosote, diesel

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5
Q

What is fraction 3 PHC used for?

A

Used to produce diesel and lubricating oils

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6
Q

what is fraction 4 PHC used for?

A

Used for waxes, bitumen/asphalt/tar

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7
Q

Polycyclic aromatic hydrocarbons (PAHs)

A

Two or more fused aromatic rings, produce when organic material is burned (combustion), natural and anthropogenic sources.
- Low solubility
- Lipophilic
- Some are pryogenic (pyrolytic), petrogenic or biogenic

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8
Q

How can PAHs affect vertebrates?

A

Relatively unreactive, metabolic pathways can alter reactivity, can be carcinogenic

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9
Q

Creosote

A

Derived from coal tar, made of PAHs, uned to treat against wood root, cans been used medicinally and as meat preserver

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10
Q

Where are PAHs found in the environment?

A

MAin sinks are soils and sediment

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11
Q

Polychlorinated Biphenyls (PCBs)

A

Very stable, inflammable, non conductive, man-made, insulating fluid, hydraulic fluid, flame retardant, persistent and hydrophobic, all anthropogenic, chronic effects on endocrine system, carcinogenic

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12
Q

Dixoins and Furans

A

Chlorinated organics, persistent and hydrophobic, not metabolized, some toxic to mammals, interfere with endocrine system and carinogenic
-Metal refineries, pulp and paper mills, manufacturing

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13
Q

Polychlorinated dibenzodioxins (PCDDs)

A

Dioxins

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14
Q

Polychlorinated dibenzofurans (PCDFs)

A

Furans

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15
Q

Chloracne

A

Acne-like eruption of cysts form the exposure (initially chlorine) halogenated aromatic compounds, inflammatory response to dioxins

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16
Q

Tetratogenicity

A

The ability to cause defects in fetal development (cleft palate)

17
Q

Agent orange

A

Chemical herbicide and defoliant used during Vietnam War. Dioxins have persisted in Vietnam ecosystem, biomagnifing and accumulating in groundwater

18
Q

Pesticides

A

Any biological or chemical agent that kills unwanted pests - plants or animals

19
Q

What is the ideal pesticide?

A
  • Kills quickly
  • Persistent to be effective, breakdown into non-toxic products
    -Cheap to manufacture - without unwanted contaminating compounds
  • Not yet invented
20
Q

Why are pesticides problematic?

A

Because many biological processes are highly conserved

21
Q

DDT, methoxychlor, chlorinated cylodienes and HCH are . . .

A

Neurotoxins, persistent, low water solubility, lipophilic, volatile
- Can interfere with vertebrate endocrine, nervous and immune systems

22
Q

DDT

A

First modern chemical pesticide, subject of “Silent Spring”, penetrates waxy cuticle of insects & kills nerve cells by disrupting Na+ balance.
- less bio-available to vertebrates
- still used in countries where malaria and leishmania is endemic

23
Q

What is DDT calculated as?

A

Summation of DDT isoforms, DDE and DDD

24
Q

What did WHO aim to eradicate using DDT?

A

Malaria

25
Q

What does DDT do?

A

Opens sodium ion channels in neurons, leading to spontaneous firings, resulting in spasm and eventual death

26
Q

What was DDT’s affects on birds?

A

Inhibit Ca-dependent ATPase in shell glands, resulting in thin bird shells

27
Q

Organophosphorus compounds

A

Nerve toxicants inhibit acetylcholinesterase, lipophlic, volatile, toxic to vertebrates, less persistent than organochlorine insecticides, in herbicides and chemical weapons

28
Q

Carbamates

A

Similar mode of action to organophosphorus insecticides, more diverse

29
Q

Pryethroid insectides

A

Synthetic variation based on natrual pyrethrin (from chysanthemum), neurotoxin, lipophilic, not persistant, alternate to DDT, but resistance is more widespread

30
Q

Neonicotinoids (“Neonics”)

A
  • Derived from nicotine
  • Binds to nicotine chlolinergic receptors, over-stimulation of nerve cells, paralysis, death
  • highly water soluble, persistent
  • completes with acetylocholine, doesn’t break down
31
Q

Phenoxyherbicides

A

Organochlorine that mimics plant hormones
- interfere with plant growth/regulation
- not persistent
- variable solubility

32
Q

Glyphosate

A
  • Widely used
  • Vertebrate high tolerance
  • Non-persistent, microbial degradtion