Unit 8: Aquatic and Terrestrial Pollution

Question 1

Point Sources of Pollution

Answer 1

Pollution that enters the environments from a single source and is clearly identified.

Ex:
1. Wastewater treatment plants
2. Electronic or automobile manufacturers
3. Paper or pulp mills
4. Oil refineries
5. Concentrated animal feeding operations (CAFO)
6. Leaking underground gasoline storage tanks

Question 2

How is point source pollution controlled?

Answer 2

The Clean Water Act requires industries of point sources to get a permit from the state and/or EPA before they can discharge any effluent into a body of water. Will also have to use effective technologies to treat the effluent before it can be discharged

Question 3

Effluent

Answer 3

liquid waste or sewage discharged into a river or the sea

Question 4

Nonpoint Sources of Pollution

Answer 4

Pollution that cannot be traded back to a single point or property (not from a single pipe). Contributions of contaminants come from many sources accumulating over a wide area and eventually reaching a level that impairs water quality

Ex:
1. Agricultural/residential areas can have excess chemicals: Fertilizers, herbicides, insecticides
2. Water from rain and snowmelt, and irrigation running off can be a source of: oil, grease, and toxic chemicals
3. Sediment from improperly managed: construction sites, crop/forest lands, eroding stream banks. It is the most significant nonpoint source

Question 5

How is nonpoint source pollution managed?

Answer 5

Nonpoint sources are not regulated through permitting but managed through programs that encourage partnerships between private landowners and businesses with local and state governments working together

Question 6

How do levels of dissolved oxygen (DO) and biological oxygen demand (BOD) change with respect to the distance from a pollution source?

Answer 6

An oxygen sag curve is used to depict the relationship between dissolved oxygen (DO) and biological oxygen demand (BOD).

Clean Zone: Biologically diverse and rich ecosystem and there is a balance of oxygen and biology oxygen demand

Decomposing: Then a pollution event that pours nutrients and phosphates into an aquatic system. Therefore the population of microorganisms that consume oxygen will rise significantly as they digest the overgrowth of algae. Increases the biological oxygen demand and the dissolved oxygen decreases rapidly.

Septic Zone: at first there is a very high biological oxygen demand and very low dissolved oxygen. But then organisms leave the area or die so the biological oxygen demand starts to decreases therefore the dissolved oxygen starts to increase slowly.

Recovery Zone: When biological oxygen demand is getting lower and dissolved oxygen is increasing until in clean zone again.

Question 7

Thermal Pollution

Answer 7

power plants or industrial factories raise the temperature of natural water bodies (by by discharging heated water — usually used for cooling machinery — directly back into rivers, lakes, or oceans without cooling it down first), which can harm aquatic ecosystems by reducing oxygen levels and stressing or killing sensitive organisms

Question 8

Warm Water and DO

Answer 8

Warm water holds less dissolved oxygen (DO) compared to cold water

Question 9

What are the ecological impacts of thermal pollution?

Answer 9

1. Slight variations in temperature can impact the survival of eggs & larvae of aquatic organisms w/ narrow ranges of tolerance → biodiversity can decline in the area
2. Die-offs can occur when DO levels are too low → decrease in biodiversity
3. Feeding, breeding, and migration behaviors can be altered → biodiversity can decline in the area

Question 10

Eutrophication

Answer 10

1. Excess nitrates and phosphate run off into a body of water; algae grow and reproduce → algal bloom
2. Algae die and get decomposed by bacteria → DO is used up by the bacteria (NOT THE ALGAE) during decomposition
3. Die-offs of aquatic organisms occur b/c of low DO levels → these areas are known as dead zones

If a body of water is described as “hypoxic” this means: low levels of
DO are present

Question 11

Eutrophic

Answer 11

High levels of algae are present due to excess nutrients

Question 12

Oligotrophic

Answer 12

Low amount of nutrients present

Question 13

What are endocrine disruptors?

Answer 13

• Chemicals that interfere (or disrupt) with the production, transport, metabolism, or function of hormones in living things
• blocks the receptor protein binding site of a hormone so that the cell cannot receive a signal
• Hormones help regulate homeostasis, reproduction, and development in the body.
• Estrogen, testosterone, insulin, serotonin (so many more!)
• lead to reproductive abnormalities, developmental defects, and possible behavioral changes

Question 14

Endocrine Disrupters are Found in:

Answer 14

They are synthetically in:
- Industrial solvents/lubricants (PCBs, dioxins)
- Plastics/plasticizers (BPA - bisphenol A, phthalates)
- Pesticides
- Pharmaceuticals
Found naturally in:
- Phytoestrogens in soy

Question 15

How do endocrine disruptors impact ecosystems?

Answer 15

Bioaccumulate in organisms then biomagnify in a food chain → top-level consumers are most impacted → they may die due to exposure to toxin → biodiversity declines

Question 16

Persistent Organic Pollutants (POPs)

Answer 16

• They are persistent → they remain present in the environment for a LONG TIME (a.k.a. “forever chemicals”)
• They are organic → composed of carbon atoms
• They are synthetic (human-made in a lab)
• They are nonpolar (not water soluble) → can be stored in fat tissue of organisms
• POPs can travel long distances via wind and water
• REMEMBER Fertilizers runoff into bodies of water; pesticides DO NOT! Pesticides build up in body tissues!

Question 17

Examples of POPs

Answer 17

1. DDT (dichloro diphenyl trichloroethane):
   - Insecticide used to kill mosquitos that transmit malaria
   - Banned in the U.S. due to biomagnification impacts on food webs
2. PCBs (polychlorinated biphenyls)
   - Industrial fluid
   - Banned in the U.S. (suspected carcinogen; causes adverse skin & liver effects)

Question 18

Clean Water Act

Answer 18

Mandates the restoration and maintenance of the chemical, physical, and biological integrity of the nation’s waters

Question 18

Safe Drinking Water Act

Answer 18

Requires minimum safety standards for community water supplies

Question 19

Resource Conservation and Recovery Act (RCRA)

Answer 19

Establishes “cradle-to-grave” tracking of hazardous materials

Question 20

Comprehensive Environmental Response, Compensation, Liability and Recovery Act (CERCLA)

Answer 20

otherwise known as CERCLA or Superfund – provides a Federal “Superfund” to clean up uncontrolled or abandoned hazardous-waste sites as well as accidents, spills, and other emergency releases of pollutants and contaminants into the environment

Question 21

Municipal solid waste (MSW)

Answer 21

refers to any waste that is generated and discarded by homes, businesses, and other entities in a given area/municipality.

MSW can be landfilled or incinerated for disposal

Question 22

Modern Sanitary Landfills

Answer 22

• Plastic or clay liner (why clay?)
  Clay because it has the lowest permeability (between the types of things in soil: clay silt and sand)
• Leachate collection system
  Leachate: forms when rainwater comes in contact with buried wastes created draws out chemicals from wastes
• Methods to trap both the leachate & methane exist! The Fresh Kills Landfill
• Leachate treatment system
• Methane collection/recovery system (due to anaerobic respiration)
• Clay cap + vegetation
• Groundwater and stormwater monitoring

Question 23

Incineration

Answer 23

Pros:
- Reduced volume of waste
- Energy generated can be used to power nearby homes and businesses (cogeneration)

Cons:
- There is still some solid waste at the end that goes into the landfill
- Emissions of NOx and PM (smog) and CO2 (climate change); respiratory issues (coughing, irritation) may arise

Question 24

Illegal dumping on land and in the ocean

Answer 24

- some items are not accepted in landfills, so people resort to dumping them illegally. - items that are dumped directly in the ocean results in large floating islands of trash that accumulate in the ocean gyres → then broken down by sunlight, the wind, and ocean waves into microplastics → “The Great Pacific Garbage Patch” is an infamous example

Question 25

Reduce, Reuse, Recycle

Answer 25

Pros: - Extends the life cycles of materials so that they get maximum use before landfilled or incinerated Cons: - There’s a limited number of times you can reuse certain materials before they degrade - Recycling requires energy and resources (+ time, money, etc.)

Question 26

Composting

Answer 26

Pros: - Enhances soil quality by adding nutrients to the soil and improving moisture and nutrient retention - Offsets methane gas generation in a landfill Cons: - Requires patience and proper technique! - If not done properly, compost piles can attract rats, bugs, etc. - Unpleasant odor (sometimes)

Question 27

Sewage Treatment: Preliminary/Primary Treatment

Answer 27

- physical - Large objects are removed via bar screens & grates - Solid waste and “grit” settles at the bottom of tanks - Items are landfilled or incinerated upon removal

Question 28

Sewage Treatment: Secondary Treatment

Answer 28

- biological - Bacteria break down organic matter → CO2 + “activated” sludge that settles in a tank - The tank is aerated to accelerate rate of decomposition by bacteria

Question 29

Sewage Treatment: Tertiary Treatment

Answer 29

- chemical - Chemical processes are applied to remove pollutants (ex: nitrates, phosphates) - Before water is pumped out/discharged, it is disinfected with UV light, ozone, chlorine, or hypochlorite to kill pathogens

Question 30

Toxicity

Answer 30

To quantify how toxic a substance is to an organism, we must consider two factors: - The dose administered (amount of the substance taken in a given amount of time) - The body weight of an organism

Question 31

How do we quantify the “toxicity” for any substance?

Answer 31

We conduct experiments to measure the Lethal Dose 50 (LD50), Effective Dose 50 (ED50), and the “Threshold” for a particular substance. Units: mg of the substance/kg of body mass Lethal Dose 50 (LD50): - This dose of the substance was measured to be acutely lethal to 50% of the animals to whom the chemical was administered under controlled laboratory conditions Effective Dose 50 (ED50): - At this dose, 50% of the animals tested displayed harmful, but not lethal effects (a.k.a. sub-lethal effects) Threshold: - the dose at which an effect can be detected

Question 32

Dysentery

Answer 32

- Inflammation of the intestines; leads to bloody diarrhea and abdominal pain - Caused by using water that has untreated sewage in it (due to lack of adequate sanitation) → presence of fecal coliform bacteria indicates contamination

Question 33

Mesothelioma

Answer 33

- Type of cancer that develops in the thin layer of tissue (mesothelium) that covers many of your internal organs - Linked to asbestos exposure (asbestos is a mineral found in insulation materials, flooring, etc.)

Question 34

Tropospheric Ozone

Answer 34

- Formed via reactions of NOx, VOCs, and sunlight - When inhaled, ozone impairs lung function → shortness of breath, inflammation of lung tissue → exacerbation or development of asthma and other respiratory illnesses

Question 35

Pathogens

Answer 35

- things that can produce an infectious agent - Pathogens are opportunistic → They take advantage of any situation (sometimes regardless of sanitary conditions) where they can infect and spread through populations (especially humans) Ex: - Viruses - Fungi - Bacteria - Parasitic Worms - Protozoa

Question 36

What leads to a more rapid spread of pathogens?

Answer 36

- Contaminated water (due to poor sanitation techniques) is consumed - Airborne droplets & aerosols are transmitted from an infected person into shared air space - Pathogen “spillover” → a disease “jumps” or “spills over” from its animal host to humans

Question 37

Climate Change and Pathogens

Answer 37

- With accelerating climate change, more situations are created for these pathogens to move and spread out further, across the globe. - Vectors (organisms that can transmit infectious agents) can now exist in areas they once could not. - The vectors are carrying these pathogens further north and south from the Equator (because these places are warmer than usual, for longer periods of time)