APES Unit 8 test review
Unit 8 APES Notes
Topic 8.1: Sources of Pollutants
Differences in Pollution Sources
Point Source Pollution:
Definition: A point source refers to a single, identifiable source of pollution (e.g., smokestack, waste discharge pipe).
Nonpoint Source Pollution:
Definition: Nonpoint sources are diffused, making them hard to identify (e.g., pesticide spraying, urban runoff).
Examples of Point Sources
Concentrated Animal Feeding Operations (CAFOs): Discharge pipes release ammonia (nitrogen source) from animal waste and fecal coliform.
Coal Power Plant: Emits CO2, NOx, SOx, and particulate matter (PM).
Leaking Underground Gas Storage Tanks:
Wastewater Treatment Facilities:
Electronic & Automobile Manufacturers:
Oil Refineries:
Oil Spills: Notable incidents include the BP spill in 2010 (Gulf of Mexico) and the Exxon Valdez spill in 1989 (Alaska).
Clean Water Act
Requirement: Industries classified as point sources must obtain a permit from the state or EPA prior to discharging effluent into any body of water.
Mandate on Treatment: Effective technology must be employed to treat effluent before discharge.
Nonpoint Sources of Pollution
Types of Nonpoint Sources:
Agriculture: Includes pesticides, fertilizers, herbicides, insecticides, and animal waste.
Sediment: Arises from improperly managed construction sites or agricultural fields as well as eroding stream beds.
Urban Runoff:
Consists of motor oil, road salt, sediments, leaking chemicals from vehicles, and grease.
Pesticides can be carried by wind or rain into other areas.
Challenges in Identifying Nonpoint Sources
Difficulty in pinpointing specific sources in urban areas due to the nature of runoff and the variety of pollutants.
Hydrological Impacts
Pre-Development vs. Post-Development:
Increase:
Impervious surfaces → Increase in drainage slope and direct runoff.
Decrease:
Evapotranspiration and groundwater recharge.
Managing Nonpoint Sources
Collaborative Efforts: Private landowners, businesses, and state/local governments must work together to manage and maintain clean areas.
Effects of Sediment Pollution
Low Dissolved Oxygen Levels:
Can suffocate fish (29259 fish reportedly affected).
Alters food webs and decreases fish populations.
Impact of Sediment:
Stable soil prevents runoff into water, whereas unstable soil contributes to sediment pollution.
Clear, cooler water supports spawning, while sediment covers spawning areas and inhabits insect habitats.
Specific Pollutants and Their Ecosystem Impacts
Studying Specific Pollutants: Aim for clarity and precision in detailing sources and impacts on ecosystems.
Study Recommendations
Action Items:
Watch AP Classroom Videos.
Read specified pages in the Withgott Book.
Competencies to develop:
Define and identify point source and nonpoint source pollution.
State how the EPA regulates point source pollution.
Identify management strategies for nonpoint source pollution.
Topic 8.2: Human Impacts on Ecosystems
Marine Challenges
Statistics:
30% of mangroves and seagrasses lost.
90% decline in large predatory fish stocks due to overfishing.
Ocean acidification linked to carbon emissions.
An estimated 100 million sharks targeted by humans annually.
Rising sea levels resulting from a 0.7°C increase in global temperatures.
Approximately 300,000 whales and dolphins killed annually as bycatch.
8-12 million tonnes of plastic enter the ocean each year.
19% of coral reefs lost and 75% of global reefs threatened.
Mass coral bleaching events, notably 93% of the Great Barrier Reef have experienced bleaching due to increased ocean temperatures.
Topic 8.3: Endocrine Disruptors & Industrial Water Pollutants
Understanding Endocrine Disruptors
Definition: Chemical compounds that interfere with endocrine systems in animals, binding to cellular receptors meant for hormones, thereby blocking hormone activity.
Examples of Sources: Birth control and other medications can enter waterways through sewage or improper disposal.
Impact on Ecosystems
Endocrine disruptors can significantly disrupt animal endocrine systems and overall ecosystem health.
Examples of Endocrine Disruptors
Heavy Metals as Endocrine Disruptors
Coal Ash and Heavy Metal Contamination
Pathways: Arsenic, lead, and mercury can attach to fly ash carried by wind, affecting regions far from the source.
Environmental Concerns: Bottom ash may leach or overflow, contaminating water sources or agriculture.
4.6- Watersheds
What is a Watershed?
Also known as a drainage basin.
Defined as: An area of land that is drained by a water system such as a river or bay.
Question: What watershed are we in?
What determines a Watershed?
Key Factors:
Slope:
Ridges divide watersheds, causing runoff to flow in different directions.
Vegetation, soil composition, and slope significantly influence how watersheds drain.
Increased Vegetation = Increased Infiltration
Slows rainwater, absorbs water, and plant roots enhance soil permeability.
Increased Slope = Faster runoff velocity = More soil erosion.
Soil Permeability: Determines the balance between runoff and infiltration of water.
Human Activities Impacting Watersheds:
Agriculture
Clearcutting
Urbanization
Dam Construction
Mining
Characteristics of a Watershed
A watershed's characteristics persistently include:
Area
Length
Slope
Soil & Vegetation types
Divides with adjoining watersheds.
Drainage Basins and Watersheds of Virginia
Mapping and understanding the geographic context of watersheds in Virginia, along with specific drainage basins:
BIG SANDY: Covers significant area in Virginia.
Smaller scale mapping indicates:
SHENANDOAH
POTOMAC
RAPPAHANNOCK
Other notable drainage basins include Chesapeake Bay, Albemarle Sound, Yadkin River, York, James, Chowan.
Our Watershed: The Chesapeake Bay Watershed
Area: 2,577 square miles
Major Tributaries: Chesapeake Bay, Piankatank
Note: Contains more than 18 trillion gallons of water - equivalent to about 27 million Olympic-sized swimming pools worth of water.
Fun Fact: The immense size of the Chesapeake Bay supports various ecological and human activities.
Chesapeake Bay Watershed Ecosystem Services
Watch the Mr. Smedes 4.6 Video to gain insights on the Ecosystem Services offered by estuaries, specifically like Chesapeake Bay.
These services are crucial for maintaining ecological balance.
Human Impacts on Watersheds
Nutrient Pollution
Leads to Eutrophication: A process encouraging excessive plant growth and decay that harms aquatic systems.
Major Sources of Nutrient Pollution:
Discharge from sewage treatment plants
Animal waste from Concentrated Animal Feeding Operations (CAFOs)
Manure lagoons can overflow or flood, contributing to nutrient loads.
Synthetic fertilizers from agricultural fields and lawns rinse into waterways during excess rain or irrigation.
Other Pollutants
Endocrine Disruptors: From sewage treatment.
Sediment Pollution: Caused by deforestation, urbanization, and tilling of agricultural fields, leading to an increase in turbidity and a decrease in photosynthesis.
Solutions to Decreasing Nutrient Loads:
A. Cover Crops: Used in farming to prevent nutrient runoff.
B. Riparian Buffers: Vegetated areas near water bodies that help to filter pollutants.
C. Managing Animal Waste: Proper care and management of manure lagoons.
D. Septic Tank and Drainfield Maintenance: Ensuring functionality to reduce leakage into watersheds.
E. Biological Waste Removal: Educating on methods to reduce waste pollution.
F. Enhanced Nutrient Removal from Sewage Treatment Plants: Upgrading facilities for better effluent quality.
Topic 8.4 Human Impacts on Wetlands and Mangroves
G. Importance of Wetlands: Wetlands serve as critical ecosystems that provide numerous benefits, including water filtration, flood protection, and habitat for diverse wildlife.
Wetlands are defined as areas where water covers the soil, either part or all the time.
They provide multiple ecological services, including:
Water purification
Flood protection
Water filtration
Habitat for diverse species.
Threats to Wetlands and Mangroves include:
Commercial development
Dam construction
Overfishing
Pollutants from agriculture and industrial waste.
Learn More About Wetlands
Wetlands defined by the University of Maryland:
Areas where the soil is submerged or saturated in water for part or all of the year but shallow enough for emergent plants.
Specific plants are adapted to withstand their roots submerged in water.
Learn More About Mangroves
Further exploration into the ecology and importance of mangroves is necessary.
Ecosystem Services of Wetlands
Groundwater Flow: Allows for recharge and distribution of groundwater.
Energy Dissipation: Wetlands dissipate stream energy to reduce erosion.
Contaminant and Sediment Filtering: Wetlands filter out pollutants, leading to cleaner outflow of water to streams.
Wildlife Habitat: Supports diverse flora and fauna.
Bacteria Role: Bacteria in the wetland ecosystem help to breakdown contaminants.
Saturated Peat: Stores and gradually releases water, providing steadier water flow.
Threats to Wetlands
Major Threats to consider:
Pollutants: Nutrients (Nitrogen, Phosphorus), sediments, motor oil, pesticides, and endocrine disruptors.
Development: Wetlands can be filled or drained for the purpose of infrastructure and urban expansion.
Water Diversion: Upstream water usage for agriculture, flood control, or drinking can lead to reduced water flow and can dry up wetlands.
Dam Construction: Reduces nutrient (N/P) flow to wetlands, which is essential for their health.
Overfishing: Alters the food web dynamics within the wetlands.
Benefits of Wetlands
Provisioning Services: Provide habitats for organisms that are utilized by humans for food and resources.
Regulating Services: Recharge groundwater, absorb floodwaters, filter water, and sequestrate carbon.
Supporting Services: Water filtration, nutrient cycling, habitats for pollinators.
Cultural Services: Linked to tourism, educational outreach, and medicinal research.
Threats to Mangroves
Drivers of Mangrove Loss:
Climate Change: The alteration in temperature and rainfall patterns adversely affect mangrove distributions; sudden sea-level changes cause local extinctions.
Logging: Results in species composition changes and fragmentation of mangrove forests.
Agricultural Conversion: Rice paddies contribute significantly to mangrove loss, particularly noted in Myanmar.
Aquaculture: Contributes to more than half of global mangrove losses, notably due to shrimp farming.
Pollution: The aerial roots of mangroves, crucial for respiration, can be smothered by sediment and solid waste.
Coastal Development: Urbanization in coastal areas accelerates mangrove degradation, with coastal populations being substantially higher than the global average.
Topic 8.5
Anthropogenic Causes of Eutrophication
Agricultural runoff
Wastewater release
The discharge of:
Untreated municipal sewage (contains nitrates and phosphates)
Nitrogen compounds from cats and factories
Treated municipal sewage (from primary and secondary treatment containing nitrates and phosphates)
Detergents (which contain phosphates)
Natural runoff (that contains nitrates and phosphates)
Manure runoff from feedlots (containing nitrates, phosphates, ammonia)
Runoff from streets, lawns, and construction lots (containing nitrates and phosphates)
Inorganic fertilizer runoff (containing nitrates and phosphates)
Runoff and erosion from activities such as cultivation, mining, construction, and poor land use.
The Phosphorus Cycle
Phosphate extraction from mines
Runoff in rivers and streams
Erosion from phosphate rocks
Fertilizer phosphate uptake by plants
Uptake by algae and other photosynthetic organisms
Organic decomposition of animal waste and decaying plants and animals
Uptake by aquatic and marine animals
Marine sedimentation
The Eutrophication Process
Nutrient load up: Excessive nutrients from fertilizers are flushed from the land into rivers or lakes by rainwater.
Plants flourish: Pollutants lead to the growth of aquatic plants such as algae and duckweed.
Algae blooms: Algal blooms block sunlight from reaching other plants, causing them to die and deplete oxygen in the water.
Decomposition further depletes oxygen: Dead plants are decomposed by bacteria, which use up even more oxygen.
Death of the ecosystem: Oxygen levels fall to a point where life is unsustainable, leading to the death of fish and other organisms.
Natural vs. Cultural Eutrophication
Natural eutrophication: A gradual process occurring over centuries as the basin fills with nutrients and sediments.
Cultural eutrophication: A rapid process occurring over decades due to human disturbances and nutrient inputs.
Hypoxic Waterways
Hypoxic waterways are those with low dissolved oxygen levels.
Comparison with eutrophic waterways:
Oligotrophic waterways have low nutrient levels, stable algae populations, and high dissolved oxygen.
Methods to Reduce Cultural Eutrophication
Remove nitrates and phosphates from water sources.
Diversion of lake water.
Clean up lakes.
Use herbicides and algaecides (noted downside).
Increase oxygen levels by adding air.
Cover Crops to the Rescue!
Importance of cover crops in managing dead zones.
Additional Materials
Add to your topic notes:
Watch the Mr. Smedes 8.5 Video
Watch AP Classroom Topic 8.5 Video
Read Withgott Associated pages noted on handouts for this topic
Topic 8.6 - Thermal Pollution
Understand the causes and effects of thermal pollution on aquatic ecosystems. Take notes on examples of thermal pollution, its sources, and the measures that can be implemented to mitigate its impacts.
Thermal pollution occurs when excess heat is released into water, causing negative effects on organisms in that ecosystem.
Variations in water temperature affect the concentration of dissolved oxygen, as warm water holds less oxygen than cold water.
Solubility of Oxygen and Temperature
A graph displaying the relationship between dissolved oxygen (in mg/liter) and temperature (°C).
General trend identified:
As temperature increases, the solubility of oxygen decreases.
How Cooling Towers Lead to Thermal Pollution
Diagram of an induced draft cooling tower:
Hot water enters the cooling tower and is cooled via air exchange facilitated by a fan and other products.
Cooled water is then distributed back into the ecosystem.
TOPIC 8.7 - Persistent Organic Pollutants (POPs)
Toxicity:
POPs can be toxic to organisms due to their fat solubility, allowing them to accumulate in the fatty tissues of living organisms.
Origin of Persistent Organic Pollutants (POPs)
Sources of POPs:
Industrial processes: Production of pesticides, plastics, and other chemicals.
Waste disposal: Burning of garbage, industrial waste, and medical waste.
Agricultural use: Pesticides, herbicides, and insecticides.
Consumer products: Flame retardants, electronics, and building materials.
Accidental spills: Leakage from transformers, capacitors, and other industrial equipment.
Byproducts of combustion: Emissions from burning fossil fuels, wood, and biomass.
Characteristics of Persistent Organic Pollutants (POPs)
Properties:
Synthetic or human-made, produced in laboratories or factories.
Fat-soluble (non-polar), meaning they dissolve in fat tissue but are not water-soluble, preventing them from being filtered through the kidneys for excretion.
POPs can travel long distances via wind and through aquatic systems, particularly in fish.
They are long-lasting and organic (composed of carbon).
POPs can be gradually released from fatty tissues into the bloodstream, potentially affecting brain and reproductive system functions over time.
Examples of Persistent Organic Pollutants (POPs)
DDT:
A synthetic organic compound used as a pesticide; it is now outdated and banned in the U.S. and many countries, but still used in some developing countries to control mosquito populations that transmit malaria.
Rachel Carson's book, "Silent Spring," highlighted the issue of DDT's impact on raptor eggs, resulting in thinning eggshells.
Phthalates:
A group of chemicals used as plasticizers in various products, including cosmetics, food packaging, and medical devices; linked to endocrine disruption and reproductive health issues.
PCBs:
Man-made chemicals that were used as industrial fluids (coolants, lubricants, etc.) until banned due to their toxicity and environmental persistence. PCBs accumulate in the food supply through fish, meat, and dairy products, leading to negative health effects including reproductive failure and cancer.
PBDEs:
Chemicals used for fireproofing in furniture and clothing.
BPA:
Bisphenol A, used in the production of polycarbonate plastics and epoxy resins found in food containers and baby bottles, with potential hormone-disrupting effects.
Perchlorates:
Used as rocket and missile fuel; they can interfere with thyroid hormone production and pose health risks, especially to vulnerable populations like fetuses and children.
Transport of Persistent Organic Pollutants (POPs)
Processes:
POPs frequently travel long distances.
They enter soil and water systems, passing through the food chain and accumulating in fatty tissues before potentially being ingested by humans or entering drinking water supplies.
Legislation to Protect against POPs
Clean Water Act:
This act regulates and controls pollution in the nation's waters, including efforts to manage POPs, through the requirement of permits for pollutant discharges, establishing water quality standards, and implementing pollution prevention programs.
Safe Drinking Water Act:
Authorizes the EPA to set national drinking water standards to protect against contaminants, including POPs, requiring public water systems to comply with these standards.
RCRA (Resource Conservation & Recovery Act):
While it does not specifically address POPs, this act provides a framework for managing hazardous waste that may contain POPs throughout its lifecycle.
CERCLA (Comprehensive Environmental Response, Compensation & Liability Act):
Also known as Superfund, this act empowers the EPA to investigate and clean up hazardous substances, including POPs, and holds responsible parties accountable for cleanup costs.
Stockholm Convention
International Treaty:
Established in 2001, designed to reduce or eliminate the production, use, and release of POPs globally to protect human health and the environment.
Acknowledges that local use leads to global effects.
Note: The USA has not ratified this treaty; thus, it is not formally bound by its terms.
POPs Summary
Protecting Resources:
It is essential to protect environmental and human health by:
Avoiding the burning of waste.
Characteristics of POPs:
POPs remain intact for longtime periods; they can become widely distributed throughout the environment and are toxic to both humans and wildlife.
Alternative Solutions:
Alternatives should not exhibit characteristics of POPs and should present a lower risk than their use in order to protect human and environmental health.
TOPIC 8.8 - Bioaccumulation & Biomagnification
Bioaccumulation
Definition:
Bioaccumulation occurs when chemicals in the environment build up in an organism’s body over its lifetime, particularly fat-soluble compounds such as DDT, methylmercury, and PCBs.
Process:
Contaminants are ingested and stored in fat tissues over time.
Biomagnification
Definition:
Higher concentrations of pollutants are found in organisms at higher trophic levels in an ecosystem.
Process:
POPs and methylmercury enter sediments/water/soil.
Producers absorb these chemicals.
Primary Consumers (e.g., zooplankton and bottom-feeding fish) ingest POPs by consuming producers, bioaccumulating them in their fatty tissues.
Secondary Consumers take in POPs when they consume primary consumers, resulting in higher concentrations.
Tertiary Consumers (largest predators) have the highest concentration due to their position in the food chain.
Example of Biomagnification
Concentration Calculation:
If the concentration in producers is 1 unit, then:
Primary Consumer: 10 units
Secondary Consumer: 100 units
Tertiary Consumer: 1000 units
Case Study: Biomagnification of DDT
Historical Context:
DDT usage was phased out in the U.S. in 1972 due to its carcinogenic properties and harmful effects on raptor egg development.
Thinning eggshells led to higher breakage rates and reduced population viability due to increased chick deformities.
DDT Timeline
Key Dates:
1930s: 600 to 800 breeding pairs of bald eagles in Chesapeake Bay.
1940s: DDT introduced widely in the U.S.
1959: Peak usage of nearly 80 million pounds.
1972: Most DDT applications banned.
2001: 646 breeding pairs of bald eagles found in the Bay.
2016: 2,000 breeding pairs found.
2020: 3,000 breeding pairs recorded.
Biomagnification of Methylmercury
Source:
Methylmercury formed from mercury in coal combustion and volcanic eruptions, attaching to particulate matter and entering aquatic ecosystems.
Effects:
Methylmercury is a neurotoxin, damaging the nervous system and causing issues like impaired communication skills, involuntary muscle movements, and reproductive, circulatory system, kidney, and liver dysfunctions.
TOPIC 8.9 Solid Waste Disposal
Understanding Solid Waste:
Definition: Solid waste refers to unwanted material or substance resulting from human activities or processes.
Distinction: The terms "decompose" and "biodegrade" are often used interchangeably; however, decomposition refers to breaking down into smaller pieces physically, while biodegradation implies a biological process usually associated with organic materials.
Caution: Claims of decomposition times by industries should be researched for accuracy.
Types of Solid Waste:
Municipal Solid Waste (MSW):
Includes non-liquid waste from homes, institutions, and small businesses; commonly known as trash or garbage.
Composition: Paper, food scraps, old appliances, furniture.
Industrial Solid Waste:
Waste from the production of consumer goods, mining, agriculture, and petroleum extraction/refining.
Hazardous Waste:
Toxic, chemically reactive, flammable, or corrosive waste, including items such as paint, household cleaners, medical waste, and industrial solvents.
E-Waste:
Electronic waste containing hazardous chemicals (e.g., heavy metals) requiring proper disposal.
Solid Waste Disposal:
Definition & Context: MSW is solid waste from domestic, industrial, business, and agricultural sectors. Common names include trash, litter, rubbish, garbage, and refuse.
Waste Stream:
Describes all production and flow of solid waste.
Composition of MSW:
Includes paper, organic compostable waste, plastic, etc.
Importance of Waste Management:
Waste management is responsible for protecting water, soil, and air quality. It serves as a measure of efficiency in industrial processes.
Components of Waste Management:
Source reduction
Recycling
Safe waste disposal
Nature automatically recycles through the decomposition of organic material, but human activity interrupts this cycle with non-biodegradable materials.
Landfill vs. Dump:
Landfills are not dumps; methods like open dumping and burning were once acceptable but became problematic due to population growth and waste generation in the late 20th century.
Issues with Open Landfills:
Odors, poor containment of leachate, risk of fire, pest disturbances, and low aesthetic value.
Illegal Dumping Concerns:
People often dump unwanted items (e.g., tires, furniture) for convenience, which can contaminate soil and water.
Breeding Grounds for Disease:
Items like rubber tires can become breeding grounds for mosquitoes, leading to health risks.
Ocean Dumping of Solid Waste:
Trash is sometimes illegally dumped into oceans, leading to dangerous concentrations in gyres due to ocean currents.
Impact on Marine Life:
Animals can become entangled, suffocate, or inadvertently consume waste, affecting food chains.
Microplastics:
Small plastic pieces can carry persistent organic pollutants (POPs) that accumulate and magnify in marine ecosystems.
Classroom Activity for Understanding Waste:
Sort through items in a trash bag, ranking biodegradability.
Estimate how long it takes for each item to biodegrade under natural conditions.
Categorize items as D (Decomposable), R (Recyclable), U (Reusable), or C (Compostable).
TOPIC 8.10 Waste Reduction Methods
Key Principles of Waste Reduction:
Reduction:
Requires less energy input for extraction, production, packaging, transport, etc.
Reuse:
Doesn’t require additional energy to produce new items (e.g., reusing furniture, containers).
Recycling:
The least sustainable of the “R”s because it requires energy to process waste into new products.
Closed Loop Recycling: Glass recycled back into new glass products.
Open Loop Recycling: Plastic bottles turned into new materials like nylon fibers.
Endless Reuse Ideas Include:
Shopping at thrift stores, using durable coffee mugs, refilling water bottles, donating surplus items, and utilizing reusable containers.
Recycling Process and Challenges:
Recycling can be confusing for consumers due to various complexities and the necessity for proper sorting.
Pros of Recycling:
Reduces demand for new resources and energy overall.
Cons of Recycling:
Costs and energy required for collection and processing; improper recycling can contaminate batches.
Composting:
Pros:
Reduces organic waste entering landfills, controlled decomposition, enriches soil, and decreases landfill volume.
Cons:
If done improperly, can create foul odors and attract pests; industrial compostable materials may not break down effectively in home setups.
E-Waste Issues:
Contains hazardous chemicals like heavy metals that can contaminate groundwater.
Legislation for Waste Management:
Clean Water Act, Safe Drinking Water Act, RCRA, and CERCLA work to manage e-waste and hazardous materials effectively, ensuring public health and environmental safety.
Legislation Relevant to Waste Management:
RCRA: Resource Conservation and Recovery Act
Regulates hazardous waste from cradle to grave.
CERCLA: Comprehensive Environmental Response, Compensation, and Liability Act
Establishes funds for cleaning hazardous waste sites (Superfund).
Brownfields: Contaminated sites needing cleanup before redevelopment.
Waste-to-Energy Plants:
Convert methane from waste into electricity, reducing landfill volumes.
Solutions for Waste Reduction:
Assignment: Track trash for 7 days to analyze type and amount of waste generated, create a visual representation (graph), and reflect on potential reduction strategies.
Zero Waste Inspiration Ideas Include:
Buy less, refuse straws, bring reusable items, reduce waste across various life areas, and engage in local environmental initiatives.
Topic 8.11: Sewage Treatment
Best Practices in Sewage Treatment
Focus on efficient sewage treatment processes to minimize environmental impact and maintain public health.
Water Flow in Sewage Systems
Sewer systems (City sewer): Channel wastewater to treatment facilities rather than employing septic systems.
Water Treatment Process
Stages of Treatment:
Primary Treatment: Initial phase for physical removal of solids.
Secondary Treatment: Biological breakdown of organic materials.
Tertiary Treatment: Advanced purification to eliminate remaining pollutants.
Detailed Stages in Sewage Treatment
Primary Treatment:
Process: Screening to filter debris (e.g., plastics, leaves, sticks).
Objective: Allow sedimentation to settle solid waste and separate lightweight materials.
Secondary Treatment:
Process: Involvement of microbes in decomposing organic matter (e.g., fecal matter, ammonia).
Removal Efficiency: Approximately 70% of phosphorus (P) and 50% of nitrogen (N) removed, but Persistent Organic Pollutants (POPs) remain.
Environmental Impact: Aimed to reduce nutrient pollution, which can trigger cultural eutrophication.
Tertiary Treatment:
Methods: May utilize both ecological and chemical processes that chemically treat water.
Disinfection Techniques: Use of UV light, ozone, or chlorine to eliminate harmful pathogens (e.g., E. coli).
Sewage Treatment Process Flow
Wastewater transported via underground pipes to treatment plant.
Large debris screened and disposed of in landfills.
Solid waste settles in tanks, forming sludge.
Aeration promotes bacterial activity converting organics into CO2 and inorganic nutrients.
Sludge managed through thickening and removal: incineration, landfill, or use in fertilizers.
Disinfection via ultraviolet light or chemicals to kill remaining pathogens.
Treated water released into nearby waterways (rivers, lakes).
Water Quality Monitoring
Conducted at each treatment stage to ensure compliance.
Legislation Impact:
Clean Water Act (CWA): Establishes standards for wastewater discharge.
Safe Drinking Water Act (SDWA): Ensures quality of drinking water and mandates permits for discharges.
Funding aid for water treatment infrastructure improvements.
Sewage Treatment Issues
Combined Sewage and Storm Water Systems: Risk of overflow during heavy rain, which can lead to untreated wastewater entering waterways.
Environmental Concerns of Overflow: Potential introduction of pathogens, ammonia, nitrates, and phosphates into local water systems.
Even treated water can have elevated nutrient levels and endocrine disruptors.
Topic 8.12: Lethal Dose 50% (LD50)
Definition of LD50
Lethal Dose 50% (LD50): The specific dose of a chemical that causes death in 50% of a given population (typically of a particular species).
Application of LD50 and ED50
Example: Comparison involving tarantulas and their prey.
Median Effective Dose (ED50): Measure of the dose that achieves a therapeutic effect in 50% of the population; synonymous with sublethal dose.
ED50 and Dose-Response Relationships
Definition: Broad application in assessing responses to various stimuli, including drugs and environmental factors.
The concept extends to fields like epidemiology for risk assessment and materials science for testing strength.
Any measurable effect in an organism can form a basis for constructing dose-response curves.
Topic 8.13: Dose Response Curve
Overview of Dose Response Curves
A tool to represent the relationship between the dose of a substance and its effect on organisms or mortality rate within a population.
Graphical Representation:
Typically plots dose on a logarithmic scale against the percentage of the population responding to the treatment.
Example of a Dose Response Curve
Visualization of effects at varying doses from 0 to 10000, displaying the mortality rate, with a notable point at LD50 indicating 50% response.
Chemical Production and Environmental Impact
Industries Contributing to Pollution
Major Industries:
Petroleum, paper production, soap, fertilizers, pesticides, paints, dyes, pigments.
Heavy Metal Pollution Sources
Sources of Heavy Metal Contamination:
Mining, metallurgy (including electronics, jewelry, and mineral processing).
Associated problems such as electroplating and wastewater management leading to bioaccumulation in aquatic food chains.
Impact on Ecosystems and Human Health:
Heavy metals present risks including cancer and organ damage, primarily affecting fish populations and subsequently, human health through consumption of contaminated seafood.
Ethical Considerations in Dose-Response Research
Use of Model Organisms
Due to ethical constraints preventing testing on humans, model organisms (e.g., mice and rats) are employed to gather data regarding potential human effects.
Types of Studies:
Acute Studies: Evaluate immediate impacts in isolated scenarios but may not reflect ecological relationships.
Chronic Studies: Assess long-term effects of substances on adult organisms.
8.14- Pollution and Human Health
Difficulty in Establishing Cause and Effect
Establishing a direct cause-and-effect relationship between pollutants and health issues is challenging due to:
Human exposure to a diverse array of chemicals and pollutants.
Synergism
Definition: Synergism refers to the interaction of two or more substances combined causes a greater effect than the effect of each individual substance or situation.
Examples of Synergism:
Asthma caused by particulate matter (PM) from coal mining combined with COVID-19 leads to greater lung damage.
Lung damage from smoking combined with the carcinogenic effect of exposure to asbestos can intensify health risks.
Routes of Exposure and Health Effects
Major routes of exposure contribute to various health issues, including:
Air Pollution:
Leads to respiratory problems and diseases such as asthma and lung cancer.
Chemical Poisoning:
Exposure to toxic substances leading to acute liver failure and various cancers.
Heavy Metal Pollution:
Linked to neurodegenerative and cognitive diseases, fertility problems, and skin lesions.
Noise Pollution:
Associated with cardiovascular diseases and other health emergencies.
Soil and Water Pollution:
Connection to endemic diseases and overall health deterioration.
Specific health issues include:
Heart rhythm problems
Diabetes and obesity
Thyroid diseases
Decreased semen quality
Polycystic ovary syndrome.
Sources of Specific Pollutants
Lead:
Found in lead pipes and old paint chips.
Mercury:
Methylmercury from seafood and tuna, linked to bioaccumulation and biomagnification.
Carbon Monoxide:
Emitted from indoor biomass combustion in developing nations and incomplete combustion from fossil fuels.
Particulate Matter:
Derived from pollen, dust, and various combustion processes.
Arsenic:
Often found in groundwater and rice, particularly from flooded fields where rice plants absorb arsenic efficiently.
Specific Health Issues Linked to Pollution
Various health issues are clearly linked to environmental conditions or exposures:
Dysentery:
Caused by untreated sewage in streams and rivers, leading to intestinal inflammation and severe dehydration. Kills approximately 1.1 million people annually in developing countries.
Symptoms: Bloody diarrhea due to intestinal swelling; can be tested for through fecal coliform bacteria.
Treatment: Early treatment with antibiotics and hydration; prevention is crucial.
Mesothelioma:
A type of cancer primarily caused by exposure to asbestos. Asbestos is a natural mineral composed of glass-like fibers that, when inhaled, damage the cellular lining of the respiratory tract and potentially the heart and abdominal cells.
Tropospheric Ozone:
A secondary air pollutant created from VOCs and NOx in the presence of sunlight; can inflame and damage airways and lungs.
Worsens existing respiratory conditions such as COPD and emphysema, and is linked to asthma, bronchitis, and other lung diseases.
Key Points Summary on Pollution and Health
Humans experience exposure to a variety of chemicals, making it difficult to establish direct cause-and-effect relationships.
Dysentery, mesothelioma, and exposure to tropospheric ozone are key health risks linked to pollution.
8.15-Pathogens and Infectious Diseases
Overview of Pathogens
Definition: Pathogens, also known as germs or infectious agents, can be viruses, bacteria, fungi, protists, protozoans, or worms that cause infectious diseases and are capable of spreading between humans.
Examples include: HIV, Ebola, COVID-19.
Transmission Methods:
Airborne, skin contact, bodily fluid contact, contact with contaminated surfaces, contact with feces, and bites from vectors.
Vectors
Definition: A vector is a living organism (e.g., mosquito, rat) that carries and transmits an infectious pathogen to other organisms.
Pathogen Spillover Event: This occurs when a disease that originates in animals spreads to humans (e.g., SARS CoV and MERS-CoV originating from bats).
Adaptation of Pathogens
Pathogens are capable of adapting to exploit new opportunities for infection, spreading through human populations.
Certain pathogens are common in various environments, regardless of sanitary conditions.
Infectious Disease in Less-Developed Nations
Higher Disease Rates: Less-developed nations often experience a higher incidence of infectious diseases due to:
Inadequate sanitary waste disposal.
Limited access to healthcare and medications.
Lack of appropriate treatment or filtration of drinking water leading to exposure to bacterial and viral pathogens.
Tropical climates and open-air living conditions increase exposure to vectors like mosquitoes.
Climate Changes and Disease Spread
As equatorial climates expand into subtropical and temperate zones, previously unknown pathogens and their vectors are emerging in these new regions.
Specific Examples of Infectious Diseases
Plague:
Caused by bacteria spread through flea bites or contact with infected animal tissues.
Tuberculosis:
A bacterial infection attacking the lungs, transmitted via air particles from infected individuals amplification of deaths primarily in poorer regions.
Malaria:
Caused by a parasitic infection from mosquito bites; significantly lethal for children under five.
West Nile Virus:
Transmitted by mosquitoes that previously bit infected birds; manifests as fever or severe neurological impacts such as meningitis or encephalitis.
Zika Virus:
Transmitted by mosquitoes and sexually; linked to birth defects like microcephaly. Prevention focuses on mosquito control and protection methods.
SARS and MERS:
Types of pneumonia caused by coronaviruses, highly infectious, particularly prevalent in specific regions, and showing severe respiratory distress.
Cholera:
Bacterial disease contracted via contaminated water, leading to severe dehydration and high mortality rates, especially in areas with poor sanitation.
Summary Points on Pathogens and Infectious Diseases
Pathogens adapt to new conditions, promoting spread and infection capabilities.
Pathogens can exist even in environments with seemingly adequate sanitary conditions.
Climate shifts lead to the emergence of diseases typical of equatorial regions into new geographic areas.