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Environmental Toxicology > Lecture 1-3 > Flashcards

Lecture 1-3 Flashcards

1
Q

what is a pollutant?

A

chemical which causes environmental harm

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2
Q

what is a contaminant?

A

chemical present at harmful levels

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3
Q

what is a biomarker?

A

biological response to a toxic compound -Molecular, cellular, organismal

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4
Q

describe xenobiotic and what it means

A
  • Anthropogenic products, do not play a functional biochemical role
  • “xeno”= new/outside/novel
  • “genic” to produce/make
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5
Q

what are toxins effects on evolution? (2)

A
  • Arms race

- Resistance

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6
Q

page 14 on first lecture

A

yay last thing:)

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7
Q

describe inorganic metals (4)

A
  • Good conductor of electricity (enters reaction as a cation)
  • Present on Earth since its formation (natural, essential, hazardous)
  • Often enter the ecotox world through mining activities
  • Form covalent bonds and can transfer electrons 
  • ->∙O2- ∙OH
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8
Q

for inorganic metals, bonding to organic groups makes ________. ______ properties can …….

A
  • lipophilic compounds
  • Lipo
  • alter chemical activity of the ionic form of the same element e.g. methylated arsenic
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9
Q

describe how the term “heavy metals” has changed from its previous meaning to its present meaning

A

Previously: density (relative to water) > 5

Now: chemical activity
e.g. Aluminum
• Fish gills in acidified lakes: causes lesions, disrupts oxygen uptake
• Deposits in human brains implicated in Alzheimer’s

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10
Q
  1. ) Metals can ……

2. ) Metals differ in their _______

A
  1. ) move freely from association to association

2. ) toxicity

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11
Q

why can metals not biodegradable

A

because they are elements; they cannot be broken down into simpler substances because they are already in the simplest form. They cannot even be broken down by chemical means

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12
Q

what are trace elements?

A

a chemical element required only in minute amounts by living organisms for normal growth.

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13
Q

give some example of trace elements

A

Fe, I, Cu, Mn, Zn, Co, Mo, Se, Cr, Ni, V, Si, As

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14
Q

Only plants need….

A

Boron (B)

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15
Q

Some metals can induce a ______ of others. Example?

A

–e.g. low [Mo] can cause Cu deficiency in cattle

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16
Q
  1. ) By themselves, 3 three compounds are not toxic

2. ) However, excessive amounts lead to _______________

A
  1. ) PO4-, NO3-, NH4+

2. ) Eutrophication

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17
Q

what is eutrophication?

A

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen

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18
Q

what is Methemoglobinemia

A

“Blue Baby Syndrome”

a blood disorder in which an abnormal amount of methemoglobin – a form of hemoglobin – is produced. With methemoglobinemia, the hemoglobin can carry oxygen but is unable to release it effectively to body tissues.

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19
Q

what are oxyradicals?

A
  • Free Radicals and Reactive Oxygen. A radical is an atom or group of atoms that have one or more unpaired electrons. -Radicals can have positive, negative or neutral charge.
    ie: O2- and OH-
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20
Q

what is an organic molecule?

A

a molecule that has a carbon

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21
Q

what is a hydrocarbon ?

A

a compound of hydrogen and carbon, such as any of those that are the chief components of petroleum and natural gas

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22
Q

what are alkanes?

A

hydrocarbons with only single bonds between the atoms.

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23
Q

what are alkenes?

A

hydrocarbons with at least one double bond.

24
Q

what are alkynes?

A

hydrocarbons with at least one triple bond

25
Q

what are aromatics? describe them (4)

A

A substance or plant emitting a pleasant and distinctive smell.

  • Base is Benzene ring
  • Can be saturated or unsaturated
  • Not always Hydrogens
  • Polycyclic aromatic hydrocarbons (PAHs)
26
Q

Hydrocarbons are typically found in…..(2)

A

Fossil Fuels

Byproducts

27
Q

describe PCBs (6)

A
  • Polychlorinated Biphenyls
  • Anthropogenic: many industrial uses
  • Stable, viscous
  • 120 present in commercial products
  • High lipid solubility
  • One of the main players in SS
  • What are the components of a PCB? Eg: dichloro-diphenyl-trichloroethane
28
Q

what are 3 other Polychlorinated Compounds?

A
  1. ) Benzodioxins (PCDDs)
  2. ) Dibenzofurans (PCDFs)
  3. ) Polybrominated Biphenyls (PBBs)
29
Q

describe Benzodioxins (PCDDs) (2)

A
  • Leftover reaction of PCBs

* Dioxin: “rat poison”

30
Q

describe Dibenzofurans (PCDFs)

A
  • Similar leftover PCB reaction

- Few commercial applications/environmental attention

31
Q

describe Polybrominated Biphenyls (2)

A
  • Fire-retardants

- Highly lipophilic

32
Q

what compounds are the primary focus of Silent Spring?

A

Organoclorine Insecticides

33
Q

describe 3 different organoclorine insecticides and say something about each

A
  1. ) DDT
    - Developed in 1939
    - Banned in 1972
    - Exported until 1985
  2. ) Aldrin/Dieldrin
    - Cyclodienes
    - introduced in the 1950s
    - Lower vertebrate toxicity (40 mg / kg body wt)
    - Crop pests, disease vectors
  3. ) Hexachlorocyclohexane
    - Somewhat polar
34
Q

Organophosphorous Insectcicides function by inhibiting _____________

A

acetylcholinesterase

35
Q

state how inhibiting acetylcholinesterase works as an insecticide and states some things about organophosphorous insecticides (5) (page 14)

A
  • “Nerve gas”: weaponized
  • Volatile and lipophilic
  • Short-lived in the environment
  • Can accumulate in phloem to target crop pests
  • Also targets vertebrate pests
36
Q

slide 17 and 18

A

Make sure to look at!:)

37
Q

describe Carbamate Insecticides (6)

A
  • Derived from Carbamic acid
  • Inhibit acetylcholinesterase
  • Usually solids
  • More water soluble than organochlorines
  • Break down readily in the environment -Typically target molluscs (but there are plant-specific carbamates)
38
Q

describe Pyrethroid Insecticides

A
  • Derived from chrysanthemum flowers
  • Inhibit insect muscle action -Photodegraded
  • Can persist in soil particles
  • Generally not toxic to humans*
  • Typical uses: vector insects (flies and mosquitos)
  • Resistance
39
Q

describe Neonicotinoids (6)

A

“Neonics”

  • Similar to nicotine
  • Less polar (probably some lipophilia)
  • Insects more sensitive than verts
  • Many chemical companies manufacture lots of neonics
  • Proposed bans in Europe
  • Associated with colony collapse disorder
40
Q

Page 6 in lecture 3

A

:) Bees

41
Q

Describe Phenoxy Herbicides (3)

A 
-Same pathway as plant growth inhibitor
(alkali salts = water soluble
esters=lipophilic)
-Control dicot weeds in monocot crops* (Dicots “grow to death”) 
-Agent Orange

*monocot crops= corn, wheat, rice, oats

42
Q

describe Anticoagulant Rodenticide

A

Blood thinner & rat poison

  • Antagonist to Vitamin K
  • Many rats have resistance
  • Lots of structurally similar compounds now used
  • Accumulate in the liver
  • Can also be biomagnified
43
Q

describe detergents

A

-Typically act as surfactants
-Polar: anionic or cationic. Or totally non polar
-Endocrine disruptors
-have the same phospholipid bilayer (or similar to) as our cells
(slide 9)

44
Q

describe chlorophenols (3)

A
  • Chlorine + wood phenols = polychlorinated phenols
  • Different from PCP the drug (Phencyclidine)
  • Acidic properties, water soluble = chemically reactive
45
Q

describe Ethinylestradiol (3)

A
  • Common in oral contraceptives (the Pill)
  • Enters through waste water
  • Cause of intersex sturgeons in Missouri River
46
Q

page 12

A

:)

47
Q

what are 3 Organometallic Compounds?

A
  1. ) Mercury (methylmercury)
  2. ) Arsenic (methylarsenic)
  3. ) Tin (tributyl tin)
48
Q

describe the organometallic compound methylmercury (2)

A
  • Becomes lipophilic, interferes with internal chemical reactions
  • Thimerosal contains ethylmercury and is cleared from the body metabolically, extremely low toxicity
49
Q

describe the organometallic compound methylarsenic

A

herbicide and defoliant

50
Q

describe the organometallic compound tributyl tin

A
  • preventing boring invertebrates in wood

- devastating dog whelks

51
Q

name and describe the four different radiation particles

A
  1. ) Alpha (a) – discharged He+, biologically damaging
  2. ) Beta (b) – e-, less biologically damaging
  3. ) Gamma (g) – electromagnetic radiation, pervasive, similar to b
  4. ) Neutron – no charge particles, liberated by a or b. Basis for nuclear fission
52
Q

what is half life? (3)

A
  • How long does it take for half of atoms to decay?
  • After 10 half-lives, considered “not different” from background
  • Safety and storage depends on the half-life
53
Q

name some radioactive isotopes that are relevant to Biochemistry?

A
  • 131I – Concentrated in the thyroid
  • 90Sr – Follows Ca pathways and accumulates in bones
  • 137Cs – Follows Fe pathways, blood
54
Q

what are the 2 Gaseous Pollutants?

A

Greenhouse Gases and Air Pollutants

55
Q

describe Greenhouse Gases (2)

A
  • CO2, CH4, O3, CFC

* Global warming, Ozone destruction, Smog, Ocean acidification

56
Q

describe Air Pollutants (2)

A
  • NOX, SOX

* Acid rain–>aquatic and soil degradation

Environmental Toxicology (6 decks)

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