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BIOL 381 > 5 - Pollutants/Chemical pollution > Flashcards

5 - Pollutants/Chemical pollution Flashcards

1
Q

What is an environmental stressor?

A

Factors that constrain productivity, reproductive success, and ecological development

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2
Q

What is a disturbance?

A

Episodic, but intense influence that causes severe biological and ecological damage

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3
Q

What is pollution?

A

Exposure to chemicals or energy (or potentially other stressors) at an intensity that exceeds the tolerance of organisms

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4
Q

When is pollution judged to occur? How is it different from contamination?

A

Judged to occur when toxicity or other kinds of ecological damage to organisms and ecosystems can be measured (i.e. quantified)

Contamination is when potentially damaging stressors are present in the environment, but intensities are too low to cause damage

All pollutants are contaminants, but contaminants must reach a certain threshold to be considered pollutants

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5
Q

Pollution can be either…

A

natural or anthropogenic

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6
Q

Types of pollution (6)

A
  1. Chemical pollution
  2. Thermal pollution
  3. Biological pollution
  4. Noise pollution
  5. Light pollution
  6. Aesthetic pollution
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7
Q

What is chemical pollution?

A

When one or more substances occur in concentrations high enough to prompt negative physiological responses in organisms, potentially causing toxicity and/or ecological change

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8
Q

What is a chemical substance

A

Any material with a definite chemical composition

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9
Q

Examples of chemical pollution

A

Pesticides, smog, petroleum

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10
Q

What is secondary pollution? e.g.

A

The release of substances that react in the environment, to synthesize chemicals of greater toxicity

E.g. Nitrogen oxides and volatile organic compounds react with sunlight to create tropospheric ozone

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11
Q

What is thermal pollution? e.g.

A

When the release of heat into the environment results in ecological stress, due to variations in species tolerance of temperature extremes
e.g. powerplants, hot springs, urban heat islands

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12
Q

What is biological pollution? e.g.

A

When humans release organisms beyond their natural range:
- non-native (invasive) species
- pathogens

e.g. Lupine (invasive flower. Brought several pathogens. Brought by european settlers in 1800s. Will kill off/outcompete the other flowering plants by taking all available N

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13
Q

What is noise pollution

A

When the level of ambient sound becomes distracting to the normal activities of humans or are detrimental to wildlife

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14
Q

What is light pollution

A
  • when artificial light levels are detrimental to wildlife
  • often occurs when excess light is bright enough to obscure starts in the night sky
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15
Q

Examples of light pollution

A
  • search lights interfering with bird migration
  • moths attracted to light (heat = thermal and light pollution) affects their migration, where they settle for reproduction
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16
Q

What is aesthetic pollution? How is it different

A
  • visual images or environments that are displeasing to many (but not necessarily) all people
  • culture-based
  • different because it only impacts humans, but we are a part of the environment
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17
Q

What is environmental toxicology?

A

The study of the environmental factors that can influence the exposure of organisms to potentially toxic chemicals
- how toxic chemicals cycle through/react to the environment
- where chemicals may occur
- more organism based

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18
Q

What is ecotoxicology

A

The study of the directly poisonous effects of chemicals, in addition to their indirect ecological effects
- how chemicals alter the species composition
- how chemical accumulation influences ecosystem processes
- impacts of chemicals on the environment and its inhabitants
- more ecosystem based

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19
Q

Acute vs chronic toxicity

A

Acute = short-term exposure to a chemical in a high enough concentration to cause biochemical or anatomical damages, or even death

Chronic = long-term exposure to low or moderate concentrations of a chemical. Over time, chronic exposure may cause biochemical or anatomical damage, or become lethal

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20
Q

What is LD50? Measurement

A

“Lethal dose 50,” the amount of a compound required to kill half of a population of experimental animals

Usually measured in amount of chemical per unit body weight

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21
Q

Chemicals with lowest LD50? Highest?

A

Lowest = botulinum toxin, dioxin, cyanide

Highest = water, vitamin C

22
Q

ED50? TD50?

A

Effective does 50 (dose producing specific effect in 50% of pop)

Toxic dose 50

23
Q

What is the relationship between survival of juvenile salmon and concentration of selenium in their tissues?

A

Selenium improves survival rate of salmon up to a point, but eventually becomes harmful and hinders survival

24
Q

What are synergistic effects?

A

Interactive impacts of toxins that are more than, or different from, the simple sum of their constituents effects
Two compounds ‘amplify’ each other together and can be harmful, despite being harmless on their own e.g. vinegar and baking soda explode when mixed

25
Q

Types of toxins

A
  • carcinogens (cancer causing; cigarettes)
  • mutagens (DNA mutations; xray radiation)
  • teratogens (sedatives)
  • allergens (over-active immune response)
  • neurotoxins
  • endocrine disruptors
26
Q

How to decrease water pollution

A
  • reduce agricultural runoff
  • improve wastewater management
  • stricter cooling regulations for power plants
27
Q

What is the global distillation effect

A

“Grasshopper effect”
At low latitudes, evaporation of pollutants exceeds deposition
Pollutants are transported by atmosphere and ocean current
Pollutants enter the polar food web and accumulate in biota

e.g. pesticide contamination in antarctic

28
Q

What are persistent organic pollutants

A

Organic compounds that are resistant to degradation/decomposition via biological, chemical and photolytic processes

29
Q

POPs include…

A

Pesticides, industrial chemicals, by-products

30
Q

Bioaccumulation vs biomagnification

A

Bioaccumulation: build up of a toxin in the tissues of animals. Animal directly consuming or exposed to something that is contaminated

Biomagnification: magnification of concentration of toxin as we move up the food chain. Uncontaminated organism consumes contaminated orgnism

31
Q

Biomagnification of Mercury in aquatic ecosystems

A

Hg and SO2 from coal-burning plant moved by wind. Inorganic Mercury and acids runoff into lake. Taken up by zooplankton, phytoplankton, small fish, large fish. Birds, humans eat fish

Slide 47

32
Q

Quantitative environmental risk assessment? Three factors

A

Evaluation of the risks associated with some sort of hazard in the environment

  1. the likelihood of encountering the hazard
  2. the likely intensity of the hazard
  3. the biological damage that is likely to result from the predicted exposure
33
Q

Environmental impact assessment

A

A study of the potential impacts of a project/activity on the environment

34
Q

Example of short term tracking of environmental change

A

Quantifying the amount of algae in a river upstream and downstream from a pipe discharging water from a municipal treatment facility

35
Q

How do we do long term tracking of environmental change?

A

Historical datasets
Paleoecology (composition of rocks tells use the amount of different compounds present millions of years ago)

36
Q

What does environmental tracking help with?

A
  • inform conservation and restoration practices
  • guide to future decision making about the environment
37
Q

Slides 59, 60

A

Paleolimnological approach

38
Q

Environmental indicators from aquatic systems

A
  • diatoms
  • chrysophytes
  • chironomids
39
Q

Environmental indicators from the land for tracking

A
  • pollen
  • mineral particles
  • insect remains
40
Q

Environmental indicators from the atmosphere for tracking

A
  • carbon particles from carbon combustion
  • fly ash from coal combustion
  • metals and other pollutants from industry
41
Q

Slides 64-68

A

Lake cores

42
Q

Two ways of determining ecological impacts?

A
  • mesocosm approach
  • whole ecosystem approach
43
Q

What is the mesocosm approach? Example

A

Isolate part of the lake with controlled conditions

See effects of different pollutants, doses, organisms, invasive species, etc

44
Q

What is the whole ecosystem approach? Example

A

Study the effects of a factor on the entire ecosystem
e.g. Experimental Lakes Area (ELA), Hubbard Brook experimental forest

45
Q

What types of whole-ecosystem experiments were run at ELA?

A

Acidification impacts, eutrophication, habitat disruption, aquaculture, adding Phosphorous etc

46
Q

Lake 226 ELA experiment

A

Divided lake into two parts
Added nitrogen, carbon to one side
Added nitrogen, carbon, and phosphorus to the other side

P caused algae bloom. Experiment does not work in the lab bc no wind (adds oxygen to lake surface). Detergents from households contained P that was running off into the lakes.

47
Q

How long did they acidify the ELA lake? How long was recovery

A

Decreased pH over ten years

Took over ten years for pH to return to normal

48
Q

What kinds of experiments were run at Hubbard Brook experimental forest?

A

Used the forest to examine the effects of clear cutting on nutrients in the river, vertebrates and invertebrates, etc

slide 81

49
Q

What was the FACE experiment?

A

Free-air CO2 enrichment experiment
Posts in a circle releasing CO2 towards the middle of the circle. See the effects of increasing atmospheric CO2 (does it increase photosynthesis?)

50
Q

What is uniformitarianism? An analogy (for long term tracking of environmental change)

A

Uni: the present is the key to the past

Analogy: application of modern organismic features to ancient organisms

BIOL 381 (13 decks)

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