Environmental Toxicology

Question 1

Name 3 Effects of Physical Properties of Water Bodies

Answer 1

1. Eutrophication
   -comes from sewage and nutrient overflows
2. Sediment pollution
   -Excess runoff
   -Sources: erosion from ag, logging, overgrazing, degraded stream banks, overgrazing, construction, mining
3. Thermal pollution
   -Industries and nuclear power plants
   -warmer water has less capacity to hold oxygen (leads to biological stress)

Question 2

4 Layers of the Atmosphere

Answer 2

Troposphere, Stratosphere, Mesosphere, Thermosphere

Question 3

4 Main Molecules in the Atmosphere

Answer 3

Nitrogen, Oxygen, CO2, Argon (and Water Vapor)

Question 4

Atmospheric Pollutants

Answer 4

Nitrogen oxides (NOX) –> leads to acidification of waters and soils
Particulate matter: PM 2.5 and 10
Ozone (O3)

Question 5

Metabolism

Answer 5

Chemical reactions carried out in organism– a response to intake of pollution

Question 6

Hydrophilic

Answer 6

Likes water (soluble in water)

Question 7

Hydrophobic

Answer 7

Does not like water (insoluble in water)

Question 8

Lipophobic

Answer 8

Doesn’t like fats

Question 9

Lipophilic

Answer 9

Likes fats (dissolves in fats, oils, etc.)

Question 10

Why is PFAS so pervasive in the environment?

Answer 10

It is hydrophobic (and hydrophilic?) and lipophilic (hard to break down in nature)

Question 11

Why are Novel Entities a cause for concern?

Answer 11

Their presence in nature has been relatively short, and we don’t know what their long-term evolutionary effects could be.

Question 12

Cocktail effect

Answer 12

Potentials for reactions between different chemicals. Also can make it hard to link a physiological, biochemical, or other change to a single pollutant

Question 13

What are Potentiation/synergistsic and antagonistic effects between pollutants?

Answer 13

Potentiation/Synergistic: Increasing each other

Antagonistic: Balancing each other

Question 14

What are pollutants transported by?

Answer 14

Water, air, soil, and organisms

Question 15

What does PBT stand for?

Answer 15

Persistant, Bioaccumulative, and Toxic

Question 16

What are some characteristics of a persistent pollutant?

Answer 16

-Won’t be broken down in nature (e.g. hydrophobic and lipophilic)
-Is favored by low temperatures (harder to break down)
-Allows substance to remain in nature for a long time
-Allows for non-local distribution of pollutant (via air, water, etc.)
-Long half-life (conditions also matter for half-life of pollutants)

Question 17

Bioaccumulation

Answer 17

The process through which pollutants are stored and accumulate in the fats of an animal, and enter the bloodstream. Hydrophilic molecules are more readily excreted through metabolization. Lipophilic molecules are more likely to stay in fatty tissues of organisms.

Question 18

Biomagnification

Answer 18

Concentrations of pollutants increase in higher trophic levels

Question 19

Endpoints for toxicity testing and assessment

Answer 19

Death
Biochemical (good or bad responses in organisms)
Physiological (organ damage, etc.)
Reproductive (e.g. thinning of egg shells)
Behavioral (e.g. changes to mating patters)

Question 20

What are POPs, and what are some examples of them?

Answer 20

Persistent Organic Pollutants

They contain carbon, are long-lived, and may be toxic

E.g. Pesticides (like DDT), Industrial chemicals, by-products

Question 21

Define PBT-M

Answer 21

Persistence - resistance to degradation in the environment
Bioaccumulative- Organisms storing substances + excretion/metabolization
Toxic- Detrimental effects on organisms- differs between individuals and species
Mobile- Transportation potential. Often charged, and water soluble, so can travel in aquatic environments.

Question 22

Is it the lipophilic or hydrophilic substance that is more
bioaccumulated? Explain your answer.

Answer 22

Lipophilic substances are commonly stored in fatty
tissues of organisms so they are more readily
bioaccumulated. However, hydrophilic substances
are water soluble meaning that those substances
are easily excreted.