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NRSC 333 > 2. Intro to Ecotoxicology > Flashcards

2. Intro to Ecotoxicology Flashcards

1
Q

What is ecotoxicology?

A

“Ecotoxicology is concerned with the study of the fate and effects of toxic substances in ecosystems, but its essential characteristic is to look at levels of biological organization (from molecular level to the biosphere) and the associated effects, or space-time continua (contaminant dispersion, interaction with ecological dynamics).”

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2
Q

What is a chemical?

A

Any substance consisting of atoms or molecules (liquid, gas, or solid)

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3
Q

What is a contaminant?

A

A substance present in greater than natural concentration as a result of human activity

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4
Q

What is a pollutant?

A

A substance present in greater than natural concentration as a result of human activity, and which has a deleterious effect on living organisms

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5
Q

What is xenobiotic?

A

A chemical that is foreign to a biological organism

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6
Q

What is a toxicant?

A

Any toxic substance

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7
Q

What is a toxin?

A

A toxicant produced by a living organism

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8
Q

How did the US EPA count the amount of chemicals in commerce today?

A

risk based approach
(less cautious approach)

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9
Q

How did the EU count the amount of chemicals in commerce today?

A

hazard based approach
(most cautious approach)

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10
Q

How did Canada count the amount of chemicals in commerce today?

A

mixed approach

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11
Q

How do we determine if chemicals are safe?

A

Standardized toxicity tests

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12
Q

Characteristics of standardized toxicity tests (3)

A
  • Facilitates comparisons
  • Credibility
  • Share data between countries
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13
Q

What do these tests on animals use?

A

Key species per taxa

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14
Q

What do animal testing usually test for?

A

LD50

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15
Q

Types of tests (6)

A
  • acute toxicity
  • chronic toxicity
  • genotoxicity
  • carcinogenicity
  • multi-generational
  • development / reproduction
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16
Q

What is an acute toxicity test? (4 points)

A
  • Acute = short term
  • Toxicity testing usually takes hours or days
  • Often a high single dose
  • Effects occur soon after exposure
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17
Q

What is a chronic toxicity test? (4 points)

A
  • Chronic = long term
  • Toxicity testing usually >10% of an organism’s lifespan
  • Often a lower dose or mixture
  • Effects take place over a long period (years)
18
Q

What is a multi-generational toxicity test?

A

You expose one generation and study the effects on subsequent generations

19
Q

What term in the risk = exposure x hazard paradigm is LD50 associated to?

A

hazard

20
Q

How many animals are used in toxicity tests

A

1500-3000 animals for a single pharmaceutical compound related to human health

21
Q

When was the first pollution related to human activity? (aka fire)

A

125,000 years ago

22
Q

What contaminants were distributed throughout the environment during the Metal Age (approx 3000 BC)? (3)

A
  • lead
  • mercury
  • nickel
23
Q

In 400 BC and the Middle Ages (5th-15th c.), what was the main contaminant?

A

Urban air pollution

24
Q

What was released into the atmosphere during the Industrial Revolution (1760-1840)? (4)

A
  • SO2
  • NO2
  • smoke
  • HCl
25
Q

What caused the release of those gases into the atmosphere during the Industrial Revolution?

A

Large scale burning of coal

26
Q

What was another issue during the industrial revolution?

A

The great manure crisis: 1,000,000 horses in New York City producing 1000 tonnes of manure daily

27
Q

What was an issue related to rivers during the Industrial revolution?

A

Rivers became conduits for human waste, leading to cholera and typhoid

28
Q

Why was the 1930s-1950s considered as the age of darkness for environmentalism?

A

because people were not aware of the vastness of the problems of chemicals

29
Q

When was the Great Smog of London

A

1952

30
Q

What was the Great Smog of London?

A
  • Severe pollution event
  • So thick it was indoor as well as outdoors
  • 5 days of ‘pea-soup’ like smog blanketed the city
31
Q

What were contributing factors to the Great Smog of London? (3)

A
  • heavy use of coal for heating homes
  • period of cold weather
  • windless conditions
32
Q

How many people died during the Great Smog of London?

A

4000-12,000

33
Q

What did the Great Smog of London lead to?

A

The British Clean Air Act (1956) to limit emissions.
First clean air act.

34
Q

What is Silent Spring (Rachel Carlson) about?

A

How there were less birds (chicks) than in the past.

35
Q

What was associated with cross-bill in double cormorants?

A

Organochlorines

36
Q

How do contaminants change over time after bans?

A

they decrease, but there always remains a background level.

37
Q

April 22nd 1970

A

First Earth Day

38
Q

What happens in 1970-1971

A
  • US EPA and Environment Canada are founded
  • Major Clean Air and Clean Water Acts established in both countries
39
Q

What happened in 1972?

A
  • Canada/US agreement on Great Lakes Water Quality
  • DDT banned (insecticide)
40
Q

What is Our Stolen Future about?

A

Endocrine disruption

41
Q

What are some current trends in ecotoxicology? (4)

A
  • Focus away from animal testing towards New Approach Methodologies (NAMs)
    ○ E.g. in vitro or in silico tests
  • Molecular Approaches
    ○ Rapid screening
    ○ Determining mechanism of action
    ○ Capturing more subtle effects
  • New chemical methods enable non-targeted screening and detection of Emerging Contaminants
  • OneHealth approach

NRSC 333 (23 decks)

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