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Ecotoxicology > Lecture 4 - DA > Flashcards

Lecture 4 - DA Flashcards

1
Q

What is the problem with organic toxicants? Why are organisms more susceptible to industry manufactured organic toxicants?

A

Organisms didn’t evolve to be resistant to organic toxicants, especially industry manufactured ones.

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2
Q

Define an organic toxicant, and inorganic toxicant.

A

Organic - chemical with carbon as the main structural element
Inorganic - chemical without carbon as the main structural element

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3
Q

Name 6 examples of organic toxicants.

A 
Hydrocarbons
Halogenated hydrocarbons
Endocrine disrupting chemicals
Pharmaceuticals
Detergents
Effluents
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4
Q

What is the polarity and solubility (water and lipid) of hydrocarbons?

A

Low polarity
High lipid solubility
Low water solubility

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5
Q

What enzyme pathway do hydrocarbons have a biological effect on? Give 2 specific examples.

A

Detoxifying enzyme pathways

Cytochrome P450 enzymes (CYP) and EROD enzyme pathway

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6
Q

What are halogenated hydrocarbons?

A

Hydrocarbons with halogens such as fluorine, bromine, and iodine.

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7
Q

What physical properties do halogenated hydrocarbons have?

A

Stable, uncreative, and viscous.

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8
Q

Are halogenated hydrocarbons soluble in water? What about oil?

A

Not soluble in water, but is in oil.

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9
Q

Name 3 general halogenated hydrocarbons. Are they very toxic or moderate?

A

Organochlorines
Organobromines
Organofluorines
Very toxic, have been blacklisted.

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10
Q

How are halogenated hydrocarbons taken in by aquatic organisms? What about terrestrial?

A

Aquatic - uptake from diet, and surrounding water.

Terrestrial - uptake from diet, dermal, and inhalation.

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11
Q

How do algae handle halogenated hydrocarbons? Are they susceptible to it?

A

Algae adsorb them, they arent susceptible, but still pool it.

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12
Q

What are two major pools of halogenated hydrocarbons?

A

Algae and sediment.

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13
Q

Where do halogenated hydrocarbons go once taken in?

A

Goes to the blood, then skeletal muscle. Is metabolised there, and redistributed to fat. If the organism is able, it will excrete it instead of fat storage.

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14
Q

Name a major route of metabolising halogenated hydrocarbons. Name an example of a pathway using this.

A

Hydroxylation, done by liver microsomal mixed function oxidase - MFO.
EROD pathway uses this.

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15
Q

Where are unmetabolised high chlorine content halogenated hydrocarbons stored?

A

In lipids.

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16
Q

Can unmetabolised halogenated hydrocarbons cross the placental barrier? Is it present in breast milk?

A

Can cross the barrier.

Is present in breast milk.

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17
Q

What is a cumulative toxicant? Are halogenated hydrocarbons a cumulative toxicant?

A

Repeated doses are additive. Halogenated hydrocarbons are cumulative.

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18
Q

What effect do halogenated hydrocarbons have on liver weight? What organelle proliferates? What effect does it have on steroid hormones?

A

Increases liver weight
Smooth ER proliferates
Degrades steroid hormones

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19
Q

What is a characteristic response to halogenated hydrocarbons from all animals?

A

Reproductive problems.

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20
Q

What are dioxins?

A

Extremely toxic compounds, formed as unwanted byproducts during synthesis of other compounds.

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21
Q

What interaction do dioxins have with soil? Is this a problem for plants?

A

Binds tightly to soil, therefore not a problem.

22
Q

Do dioxins leach? Can they be degraded?

A

They do not leach.

Can be degraded, but has a long half-life.

23
Q

What effect do dioxins have, and where does it accumulate?

A

Teratogenic effects, deformities, and reproductive problems.

Slowly accumulates in the liver.

24
Q

Are endocrine disrupting chemicals natural or synthetic?

A

Can be both.

25
Q

Name 5 endocrine disrupting chemicals.

A

Some pesticides, metals, some halogenated hydrocarbons, oestrogen, and androgen.

26
Q

Where do endocrine disrupting chemicals come from?

A

Domestic sewage, cattle feedlot, agricultural runoff, effluents, landfills, mining activity.

27
Q

What are thyroid hormones responsible for?

A

Metabolism and metamorphosis.

28
Q

Name 3 sex hormones.

A

Oestrogen, progesterone, and testosterone.

29
Q

What does an oestrogenic disruption cause?

A

Feminisation of males, reduced fertility.

30
Q

What is does an anti-oestrogenic disruption cause?

A

Altered maturation, reproductive problems

31
Q

What does an androgenic disruption cause?

A

Masculinisation of females.

32
Q

What does an anti-androgenic disruption cause?

A

Reproductive problems

33
Q

What are pharmaceuticals?

A

Synthetic compounds developed to treat diseases, are targeted and specific.

34
Q

How do pharmaceuticals enter the environment?

A

After passing through humans, into sewage.

35
Q

What are three types of detergents?

A

Anionic
Cationic
Non-ionic

36
Q

What do anionic detergents contain?

A

Sulphate, sulphonate, carboxylate ions.

37
Q

What do cationic detergents contain?

A

Ammonium salts.

38
Q

What do non-ionic detergents contain?

A

Alkylphenol ethoxylates - APEs

39
Q

What is nonylphenol? How is it released?

A

Common non-ionic detergent. Released in industrial effluents.

40
Q

What is nonylphenol similar in structure to? What does this lend it?

A

Similar to oestrogen, binds to oestrogenic receptors - is oestrogen mimmicking.

41
Q

What endpoint is useful for measuring nonylphenol?

A

Meaure vitellogenin in male fish. Is normally found in female fish.
Oestrogen mimicking effects of nonylphenol will cause vitellogenin presence in male fish.

42
Q

What are effluents?

A

Cocktail of chemicals.

43
Q

The ability of a chemical to bioconcentrate is related to what? What is a major factor influencing this?

A

Rate of uptake vs rate of elimination.

Affected by lipid solubility.

44
Q

Define bioconcentration.

A

Process by which chemicals enter the organism from the environment.

45
Q

Define bioaccumulation.

A

Like bioconcentration, along with accumulation of chemicals from diet.

46
Q

Define biomagnification.

A

Like bioconcentration and bioaccumulation, tissue concentration of chemicals increase at higher trophic levels - ie mercury in sea creatures.

47
Q

What is the bioconcentration factor?

A

The ability of an organism to accumulate a toxicant from the environment.

48
Q

How is the bioconcentration factor calculated?

A

Take the concentration of the chemical in the tissue, divided by the concentration in the environment (water or soil).

49
Q

What is the octanol-water partition coefficient?

A

Kow. Is a chemical method of expressing the lipophilicity of a chemical.

50
Q

How is Kow calculated, and what is done to linearise it?

A

Is logged to linearise.

Log Kow = log ([toxicant in octanol] / [toxicant in H2O])

Ecotoxicology (22 decks)

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