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Env. Science (Sec.4) > Ecotoxicology > Flashcards

Ecotoxicology Flashcards

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1
Q

What is a toxicant?

A

chemical that has an effect on an organism

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2
Q

What is a toxin?

A

substance produced by a living organism which is poisonous at a certain level

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3
Q

What does hydrophobic mean?

A

substance that repels water or will not dissolve in water

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4
Q

What does hydrophilic mean?

A

substance that will easily dissolve in water

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5
Q

What does xenobiotic mean?

A

man-made chemical found in a biological system that is not naturally found there

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6
Q

What is poison?

A

substance that can cause biological disturbances to a living organism at a certain dosage

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7
Q

What is a dose?

A

quantity of drug to be administered all at one time or over a given period of time

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8
Q

What makes a chemical poisonous?

A

the dosage

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9
Q
  1. Lethal Dose Fifty (LD50) is one way the _____ of chemicals are measured.
  2. What is LD50?
  3. How is LD50 measured?
A
  1. toxicity
  2. amount of a toxicant required to kill half (50%) of a population
  3. mg of toxicant/kg of animal’s body weight
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10
Q
  1. What is Lethal Concentration 50 (LC50)?

2. How is LC50 measured?

A
  1. Concentration of a toxicant in an environment which produces death in 50% of a population
  2. mg of substance/L of air or water
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11
Q
  1. What is Toxic Dose 50 (TD50)?
  2. The _______ the TD50, the more toxic the chemical is.
  3. What does NOEL stand for and what does it mean?
A
  1. dosage that produces toxic effects in 50% of the population
  2. lower
  3. No Observable Effect Level: highest dose of a toxicant that produces no noticeable toxic effect on animals
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12
Q

What are the three ways chemicals can enter the body?

A
  1. Ingestion
  2. Inhalation
  3. Absorption
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13
Q

The skin is a major barrier that protects agaisnt chemicals. What is its main layer of defense?

A

Stratum corneum

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14
Q
  1. What is the stratum corneum?

2. Why is it used as a defense agaisnt chemicals?

A
  1. Thick layer of dead and flattened skin cells

2. Water-proof, contains the protein keratin which allows for protection agaisnt damage

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15
Q

What do the kidneys do to prevent toxicity?

A

Allows toxicants to be excreted via the urine

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16
Q

What does the liver produce and how does this help to prevent toxicity?

A

Bile. Toxicants get stored into the bile and released in the feces

17
Q

What is the “first pass effect”?

A

When a toxicant absorbed by the gastrointestinal tract must first go to the liver before it enters the body circulation

18
Q

How do proteins help prevent toxicity?

A

bind to toxicants and eliminate them

19
Q

What is bio accumulation?

A

the degree to which a toxicant can accumulate in a living organism (through inhalation, ingestion, and dermal exposure).
when an organism takes in a toxic substance faster faster than it is expelled and it accumulates in tissue

20
Q

The degree of bio accumulation depends on the rate of _____ versus the rate at which an organism is capable of _____ and _____ the toxicant.

A

intake
breaking down
eliminating

21
Q
  1. What does Kow stand for?
  2. What is it used for?
  3. What is the formula?
  4. Why octanol?
A
  1. Octanol-Water Partition Coefficient
  2. Used in environmental studies to determine the fate of chemicals in the environment
  3. How well the toxicant dissolves in octanol/how well the toxicant dissolves in water
  4. octanol is similar to fat tissues (the more it dissolves in fat the more it bio acumulates)
22
Q
  1. What is bio concentration?

2. What is a bio concentration factor?

A
  1. the uptake of a substance to concentrations in the tissues of an organism that are greater than in the surrounding
    environment
  2. concentration of chemical in tissue/concentration in water
23
Q

What is bio magnification?

A

The increase in concentration of a toxicant as it passes through to higher levels of a food web

24
Q

DDT was the first insectice to come into widcespread agricultural use. What were the benefits of it?

A
  1. Penetrates the insect
  2. Enters the cells, binds to nerves, causes death
  3. Toxicity low in humans and animals because tissues absorb less
  4. Does not wash away easily
25
Q

How did DDT impact ecosystems?

A
  1. Kill mosquito=> parasitic wasp died=> overpopulation of caterpillars=> caterpillars ate the roofs off the villagers houses
  2. DDT accumulated in geckos=> cats ate geckos and died=> rat population flourished=> outbreak of plague
26
Q

What is environmental remediation?

A

process of decontaminating soil or water

27
Q

What is mechanical remediation?

A

excavating (pumping) all the soil in an area so that it can be filtered or chemically treated

28
Q

What is biodegration?

A

breaking down of organic matter into inorganic matter by microorganisms and fungi

29
Q

What is bioremediation?

A

use of microorganisms to clean up a polluted site

30
Q

What is phytoremediation?

A

use of plants to eliminate contaminants from a polluted site

Env. Science (Sec.4) (3 decks)

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