Unit 8 Notes: Aquatic & Terrestrial Pollution

8.1 Sources of Pollutants

Point Source Pollutants:
- Pollutants from a single, identifiable location.
- Examples:
 - Animal waste runoff from a CAFO.
 - Emissions from a smokestack of a coal power plant ( $CO2$ , $NOx$ , $SO_2$ , PM).
 - BP Oil Spill (hydrocarbons, benzene).
Nonpoint Source Pollutants:
- Pollutants from multiple sources, making them difficult to pinpoint.
- Examples:
  - Urban runoff (motor oil, nitrate fertilizer, road salt, sediment).
  - Pesticides sprayed on agricultural fields carried by wind into bodies of water.
  - Estuaries and bays are affected by nonpoint pollution from large watersheds.
Pollutants vs. Pollution:
- Pollutants are specific chemicals from specific sources with specific environmental and human health effects.
- Pollution is a vague term for any harmful substance.
- On FRQs, use specific pollutant names, sources, effects, and mitigation strategies.
- Exceptions: categories like thermal, noise, and sediment pollution.

8.2 Human Impacts on Ecosystems

Range of Tolerance:
- Organisms have a range of tolerance for abiotic conditions (pH, temperature, salinity, sunlight, nutrient levels).
- Organisms also have a range of tolerance for pollutants.
- Pollutants lead to physiological stress:
  - Limited growth and reproduction.
  - Difficulty respiring, potentially asphyxiation.
  - Hormonal disruption.
  - Death (if concentration is high enough).
pH Tolerance:
- As pH decreases outside a species' optimal range, its population declines.
- When pH leaves range of tolerance, species cannot survive due to:
 - Aluminum toxicity.
 - Disrupted blood osmolarity (Na+/Cl- balance).
- Aquatic species have different pH tolerances.
- Indicator species (e.g., whitemoss/filamentous algae for pH < 6.0, crustaceans for pH > 6.0) are used to determine ecosystem conditions.
Temperature Tolerance of Reef Algae:
- Coral reefs have a mutualistic relationship with zooxanthellae algae, where algae supply sugar and coral supply $CO_2$ + detritus.
- Algae have a narrow temperature tolerance; they leave the reef when temperature rises.
- Coral loses color, becomes stressed, and vulnerable to disease without algae.
- Pollutants from runoff (sediment, pesticides, sunscreen) can force algae from the reef.
Human Impacts on Coral Reef:
- Greenhouse gas emissions warm ocean temperature, leading to coral bleaching.
- Urban and agricultural runoff damages coral reef ecosystems.
  - Sediment pollution reduces sunlight, inhibiting photosynthesis.
  - Toxicants from sunscreen, oil, and pesticides.
  - Nutrients (P/N) from animal waste and fertilizers.
- Overfishing decreases fish populations, and bottom trawling breaks reef structure and stirs up sediment.
Oil Spill Effects:
- Hydrocarbons in crude oil are toxic to marine organisms, especially upon ingestion or absorption.
  - Decreased visibility and photosynthesis.
  - Oil sticks to bird feathers.
  - Oil sinking kills bottom-dwellers via direct toxicity or suffocation.
- Oil washing ashore decreases tourism and fishing industry revenue.
- Oil in estuary habitats can kill salt marsh grasses, leading to coastline erosion and loss of breeding grounds.
Oil Spill Clean Up:
- Oil spills occur from underwater oil well explosions or tanker punctures.
- Cleanup involves:
  - Booms on the surface and ships with vacuum tubes or skimmers.
  - Physical removal of oil from beaches.
  - Chemical dispersants to break up and sink oil.
  - Burning oil off the surface.
- Dispersants can smother bottom-dwellers, and dispersant chemicals may be harmful.

8.3 Endocrine Disruptors & Industrial Water Pollutants

Endocrine Disruptors:
- Chemicals that interfere with hormonal systems.
- Bind to cellular receptors, blocking or amplifying hormone effects.
- Human medications that pass through urine into sewage are a common source.
  - Example: Atrazine herbicide leads to high estrogen in male frogs, low sperm count, and feminization.
Examples of Endocrine Disruptors:
- Atrazine: herbicide used to control weeds, contaminates water and produce.
- DDT: insecticide, phased out but still persists in the environment.
- Phthalates: compounds in plastic and cosmetics, enter water via waste disposal and landfill leaching.
- Lead, arsenic, mercury: heavy metals.
- Many human medications entering sewage.
Mercury:
- Naturally occurring in coal, released by combustion, incineration, and heating limestone.
  - Attaches to PM and deposits in soil/water.
- Endocrine disruptor: inhibits estrogen and insulin.
- Teratogen: accumulates in the fetus brain.
- Bacteria convert mercury to methylmercury, a neurotoxicant that damages the central nervous system.
Arsenic & Lead:
- Arsenic: naturally in rocks, can dissolve into drinking water, worsened by mining.
  - Formerly in pesticides, wood treatment chemicals, coal combustion.
  - Carcinogenic and endocrine disrupting.
- Lead: found in old paint, water pipes, and contaminated soils.
  - Released in fly ash of coal combustion.
  - Neurotoxicant and endocrine disruptor.
- Both can be removed with water filters.
Coal Ash:
- Source of mercury, lead, and arsenic.
- Can attach to fly ash (PM) and be deposited far away.
- Stored in ponds on site, which can leach into groundwater or runoff into nearby surface waters.

4.6 Watersheds

All of the land that drains into a specific body of water.
Determined by slope; ridges divide watersheds.
Vegetation, soil composition, and slope influence drainage.
- More vegetation increases infiltration and groundwater recharge.
- Greater slope increases runoff velocity and soil erosion.
- Soil permeability determines runoff vs. infiltration rates.
Human activities impact water quality.
- Examples: agriculture, clearcutting, urbanization, dams, mining.
Chesapeake Bay Watershed:
- 6-state region draining into Chesapeake Bay.
- Mix of fresh and salt water + nutrients make estuary habitats productive.
- Ecosystem services:
  - Tourism revenue.
  - Water filtration.
  - Habitats for food sources.
  - Storm protection.
Direct Effects of Clearcutting:
- Soil erosion due to loss of stabilizing root structure.
- Increased soil and stream temperature due to loss of tree shade and increased turbidity.

Solutions to Watershed Pollutants

Cover crops: absorb nutrients.
Riparian buffers.
Animal manure management.
Septic tank upgrades.
Enhanced nutrient removal.

8.4 Human Impacts on Wetlands and Mangroves

Wetlands:
- Areas with soil submerged/saturated in water for part of the year with shallow water for emergent plants.
- Ecosystem Services:
  - Provisioning: habitat for foods.
  - Regulating: groundwater recharge, floodwater absorption, $CO_2$ sequestration.
  - Supporting: water filtration, pollinator habitats, nutrient cycling, pest control.
  - Cultural: tourism revenue, fishing license, research.
Threats to Wetlands:
- Pollutants (N/P), sediment, motor oil, pesticides, endocrine disruptors.
- Water diversion reduces water flow and dries wetlands.
- Dam construction reduces water and sediment flow.
- Overfishing disrupts food webs.
- Development fills or drains wetlands.
Benefits of Mangroves:
- Timber and fuel source.
- Support livelihoods of 120 million people
- Climate regulation: high carbon storage in the soil
- Coastal protection
- Water filtration
- Tourism.
- Fisheries.

8.5 Eutrophication

Eutrophication:
- Extra input of N & P leads to excess nutrients, fueling algae growth.
- Algae bloom blocks sunlight, killing plants below.
- Algae die-off, bacteria use up $O_2$ , killing aquatic animals.
- Creates positive feedback loop: less $O2$ → more dead organic matter → more bacterial decomposition → less $O2$ .
Cultural Eutrophication:
- Algae bloom due to increase of N/P → decreased sunlight → plants die → bacteria use up $O_2$ for decomp. → hypoxia & dead zones.
Major N/P Sources:
- Discharge from sewage treatment plants.
- Animal waste from CAFOS.
- Synthetic fertilizer from ag. fields & lawns.
Oligotrophic Waterways:
- Low nutrient (N/P) levels, stable algae population, and high dissolved oxygen.
- Aquatic ecosystems naturally undergo succession; sediment buildup leads to higher nutrient levels.
Dissolved Oxygen & Dead Zones:
- Decrease in dissolved oxygen (hypoxia) causes a dead zone.
- Aquatic life requires DO for respiration.
- As DO decreases, fewer species can be supported.

8.6 Thermal Pollution

Solubility of Oxygen & Temperature:
- Inverse relationship between water temperature and oxygen solubility.
- As water तापमान⬆, DO तापमान⬇
- Thermal pollution: heat released into the water has negative effects on organisms.
  - Heat increases respiration rate.
  - Hot water also has less $O_2$ .
Sources of Thermal Pollution:
- Power plants cooling steam.
- Steel mills, paper mills, and other manufacturing plants cooling machinery.
- Nuclear power plants use large amounts of cool water.
- Urban stormwater runoff.
Cooling Towers:
- Used to cool steam back into water & to hold warmed water before returning to local surface water

8.7 Persistent Organic Pollutants (POPs)

Synthetic compounds that do not easily break down in the environment and accumulate in water and soil.
Fat-soluble, accumulate in animals’ fat tissue.
Can be released from fatty tissue over time.
Examples & Sources of POPs:
- Pesticides (DDT), PCBs (plastic/paint additive), PBDEs (fire-proofing), BPA (plastic additive), Dioxins (fertilizer production & combustion of waste and biomass).
- Medications (pharmaceutical compounds) persist in streams/rivers & disrupt aquatic organisms’ endocrine function.
Examples & Transport of POPs:
- PCBs: additives in paint and plastics, leading to spawning failure and endocrine disruption.
- Perchlorates: given off by rockets or fireworks, remain in soil, and can leach into groundwater.
- POPs travel long distances through wind and water.

8.8 Biomagnification

Bioaccumulation:
- Absorption and concentration of compounds in the cells & fat tissues of organisms.
- Fat-soluble compounds build up in fat tissue.
Biomagnification:
- Increasing concentrations of fat-soluble compounds in each level up the trophic pyramid or food web/chain.
- Starts with POPs or methylmercury in sediments or plants.
- Primary consumers take in POPs by eating producers, causing bioaccumulation.
- Secondary consumers eat primary consumers and take in POPs.
- Large predators have highest POP methylmercury levels.

8.9 Solid Waste Disposal

Solid Waste Types and Sources:
- MSW (Municipal Solid Waste): trash from cities.
- E-Waste: old electronics, considered hazardous waste due to metals.
Sanitary Landfills:
- Clay/plastic bottom liner: prevents* pollutants from leaking out into soil/groundwater.
- Leachate Collection System: system of tubes/pipes at bottom to collect leachate for treatment & disposal.
- Methane Recovery System: system of tubes/pipes to collect methane gas
- Clay Cap: Clay-soil mixture used to cover the landfill.
Landfills Contents & Decomposition:
- Low rates of decomposition due to low $O_2$ , moisture, and organic material.
- Things that should NOT be landfilled: hazardous waste, metals, old tires.
- Things that SHOULD be landfilled: cardboard/food wrappers, rubber, plastic films/wraps, Styrofoam.
Landfill Issues:
- Groundwater contamination with heavy metals ,acids, medications, and bacteria if leachate leaks through lining into soil/groundwater beneath.
- Greenhouse gases ( $CO2$ and $CH4$ ) are released from landfills due to decomposition, which contribute to global warming & climate change.
- NIMBY = idea that communities don’t want landfills near them for a number of reasons.
Waste Incineration & Ocean Dumping:
- Waste can be incinerated to reduce volume (reduces volume by 90%, but releases $CO2$ and air pollutants (PM, $SOx$ , $NO_x$ ). Bottom ash may contain toxic metals stored in ash ponds.
- Illegal ocean dumping suffocates animals if they ingest (eat) it or entangle them so they can’t fly or swim and may starve.

8.10 Waste Reduction

The Three Rs:
- Reducing consumption is the most sustainable b/c it decreases natural resources harvesting and the energy inputs to creating, packaging, and shipping goods.
- Reusing = the next most sustainable b/c it doesn’t require additional energy to create a product.
- Recycling = processing and converting solid waste material into new products (least sustainable of the three Rs due to the amount of energy it requires to process and convert waste materials).
Recycling Pros and Cons:
- Pros: Reduces demand for new materials/energy, reduces landfill volume.
- Cons: Costly, citizens recycle what shouldn’t be.
Composting:
- Organic matter decomposed under controlled conditions. Reduces landfill volume and produces rich organic matter.
E-Waste:
- Waste from electronics often contains heavy metals Can be recycled and reused to create new electronics but often sent to developing nations for recycling due to health hazards
Waste to Energy:
- Waste can be incinerated to reduce the volume & also generate electricity.

8.11 Sewage Treatment

Water Treatment Process:
- Primary Treatment: Physical removal of large debris.
- Secondary Treatment: Biological breakdown of organic matter
- Tertiary Treatment: Ecological or chemical treatments to reduce pollutants.
- Disinfectant: UV light, ozone, or chlorine is used to kill bacteria.
Primary Treatment Detail:
- Screens filter out large solids. Grit chamber allows sediment to settle out & be removed.
Secondary Treatment Detail:
- $O2$ is bubbled into aeration tank filled with bacteria to break down organic matter into $CO2$ and nutrients.
- Removes 70% of P and 50% of N.
Tertiary Treatment Detail:
- uses chemical filters to remove more of the nitrates & phosphates from secondary treatment discharge
Sewage Treatment Issues:
- Combined sewage and storm water runoff systems can cause wastewater treatment plants to flood, rereleasing raw sewage
- Even treated wastewater effluent released into surface water often has elevated N/P levels and endocrine disruptors

8.12 & 8.13 $LD_{50}$ & Dose Response Curve

Dose Response Studies & $LD_{50}$ :
- Studies that expose an organism to different doses of chemicals to measure the response (effect) of the organism.
- $LD_{50}$ refers to the dose or concentration of the chemical that kills 50% of the population being studied.
- LD50 data are usually expressed as:
  - Mass/body unit mass (kg)
  - ppm - parts per million (in air)
- Mass/volume (in water of blood)
Dose Response Curve:
- The data from a dose response study, graphed with percent mortality or other effect on the y-axis and dose concentration of chemical on x-axis
Dose response curves are usually “S-shaped” - low mortality at low doses, rapid increase in mortality as dose increases, level off near 100% mortality at high dosage

8.14 Pollution and Human Health

Routes of Exposure & Synergism:
- Routes of Exposure: Ways that a pollutant enters the human body
  - Synergism: The interaction of two or more substances to cause an effect greater than each of them individually ex:*Carcinogenic effect of asbestos combined with lung damage from smoking
Dysentery:
Bacterial infection caused by food or water being contaminated with feces can be treated with antibiotics.
Mesothelioma (asbestos)
A type of cancerous tumor caused by exposure to asbestos, primarily affecting the lining (epithelium) of the respiratory tract, heart, or abdominal cavity
Tropospheric Ozone ( $O_3$ ): Worsens respiratory conditions like asthma, emphysema, bronchitis, COPD is only harmful in the troposphere.
Sources: photochemical breakdown of $NO_2$ (car exhaust, coal & NG combustion)
*8.15 Pathogens and Infectious Diseases
Pathogens & Vectors:
- Pathogen: A living organism that causes an infectious disease.
- Vector: A living organism that carry and transmit infectious pathogens to other organisms.
  expanding Aedes aegypti range
Vector for dengue fever, Zika virus, yellow fever
Infectious Disease & Development Less developed, poorer countries typically have higher rates of infectious disease
*Plague
Bacterial (pathogen) infection transmitted by fleas (vector) that attach to mice & rats (vectors as well)
Aka “bubonic” or “black” plague; modern antibiotics are highly effective against it, but some isolated instances still occur
*Tuberculosis (TB)
Bacterial (pathogen) infection that targets the lungs
Transmitted by breathing bacteria from body fluids (resp. droplets) of an infected person, which can linger in air for hoursCauses night sweats, fever, coughing blood; treatable in developed nations with access to powerful antibiotics
*Malaria
parasitic protist (pathogen) infection caused by bite from infected mosquitoes (vector)
sub-Saharan Africa (& other tropical regions of Middle East, Asia, South & Central America; recurring flu-like symptoms; kills mostly children under 5
Can be combated with insecticide spraying that kills mosquitoes; US eradicated in 1951
*West Nile
Virus (pathogen) infection caused by bite from infected mosquitoes (vector)
Birds are the main host, but the virus can be transmitted to humans by mosquitoes that bite infected birds and then bite humans *Causes brain inflammation, which can be fatal.
*Zika Virus
virus (pathogen) infection caused by bite from infected mosquitoes (vector) & sexual contactCauses babies to be born with abnormally small heads and damaged brains; Can be passed from mother to infant and has No known treatment currently
*Cholera
Bacterial (pathogen) infection caused by drinking infected waterVomiting, muscle cramps and diarrhea; can cause severe dehydration *Can be introduced by water contaminated with human feces or undercooked seafood.
*SARS (Severe Acute Respiratory Syndrome)
Coronavirus (pathogen) infection caused by respiratory droplets from infected person Causes a form of pneumonia
*MERS (Middle East Respiratory Syndrome)
Virus (pathogen) respiratory infection transmitted from animals to humans Originated on Arabian peninsula

Unit 8 Notes: Aquatic & Terrestrial Pollution

8.1 Sources of Pollutants

8.2 Human Impacts on Ecosystems

8.3 Endocrine Disruptors & Industrial Water Pollutants

4.6 Watersheds

Solutions to Watershed Pollutants

8.4 Human Impacts on Wetlands and Mangroves

8.5 Eutrophication

8.6 Thermal Pollution

8.7 Persistent Organic Pollutants (POPs)

8.8 Biomagnification

8.9 Solid Waste Disposal

8.10 Waste Reduction

8.11 Sewage Treatment

8.12 & 8.13 LD50LD_{50}LD50​ & Dose Response Curve

8.14 Pollution and Human Health

8.12 & 8.13 $LD_{50}$ & Dose Response Curve