Subtopic Number |
Subtopic |
AP Points to understand |
8.1 |
Sources of Pollution |
Point Source Pollution: This type of pollution comes from a single, identifiable source, such as a factory or sewage treatment plant. Point source pollution can be easier to control and regulate than non-point source pollution.
Non-Point Source Pollution: This type of pollution comes from diffuse sources, such as agricultural runoff, urban runoff, and atmospheric deposition. Non-point source pollution is often more difficult to identify and control than point source pollution. |
8.2 |
Human Impacts on Ecosystems |
- Habitat Destruction: Habitat destruction is the process of changing natural habitats into modified or degraded landscapes. It is one of the primary causes of biodiversity loss and occurs due to human activities such as deforestation, mining, urbanization, and agricultural expansion.
- Habitat Fragmentation: Habitat fragmentation occurs when large, contiguous habitats are broken up into smaller, isolated patches due to human activities such as road construction and urbanization. Fragmentation can lead to decreased genetic diversity, increased predation, and decreased migration among species.
- Pollution: Pollution refers to the introduction of harmful substances into the environment that can cause harm to living organisms. Pollution can occur in many forms, including air pollution, water pollution, and soil pollution. Human activities such as burning fossil fuels, industrial activities, and agricultural practices are the primary sources of pollution.
- Overexploitation: Overexploitation occurs when humans use natural resources at a rate that exceeds their ability to replenish themselves. This can lead to depletion of resources and ultimately result in the collapse of ecosystems. Examples of overexploitation include overfishing, overhunting, and deforestation.
- Climate Change: Climate change is the long-term alteration of temperature and typical weather patterns in a place. It is primarily caused by human activities such as burning fossil fuels, deforestation, and agriculture.
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8.3 |
Endocrine Descriptors |
- Endocrine Disruptors: Chemicals or mixtures of chemicals that can interfere with the endocrine (hormonal) system of animals and humans, causing developmental, reproductive, neurological, and immune effects. They can be found in pesticides, plastics, flame retardants, pharmaceuticals, and personal care products.
- Examples of Endocrine Disruptors: Bisphenol A (BPA), Dioxins, PCBs, Phthalates, Triclosan, and Atrazine.
- Effects of Endocrine Disruptors: Endocrine disruptors can cause a wide range of adverse effects in humans and wildlife, including altered reproductive function, developmental abnormalities, immune suppression, and increased incidence of cancer.
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8.4 |
Human Impacts on Wetlands and Mangroves |
- Wetland and mangrove loss: Human activities such as agriculture, urbanization, and infrastructure development have led to the destruction and fragmentation of wetlands and mangroves, resulting in their loss and degradation.
- Wetland and mangrove restoration: Restoration of degraded or destroyed wetlands and mangroves is a vital process to bring back the ecological services provided by these ecosystems. Restoration activities include the removal of invasive species, the creation of new wetlands and mangroves, and the reintroduction of native flora and fauna.
- Wetland and mangrove conservation: The conservation of wetlands and mangroves involves the protection of these ecosystems from further degradation and destruction. Conservation activities include the creation of protected areas, regulation of activities that may damage these ecosystems, and the promotion of sustainable practices that take into account the value of wetlands and mangroves.
- Eutrophication: Excess nutrients from human activities such as agricultural runoff and sewage can cause eutrophication in wetlands and mangroves. Eutrophication leads to the growth of harmful algal blooms, which can be toxic to aquatic life and humans.
- Overfishing and destructive fishing practices: Overfishing and destructive fishing
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8.5 |
Eutrophication |
- Eutrophication: Eutrophication is a process in which an aquatic ecosystem becomes enriched with nutrients, particularly phosphorus and nitrogen, resulting in increased growth of algae and other aquatic plants. This increased growth can have negative impacts on the ecosystem, such as reduced oxygen levels, fish kills, and changes in the composition of the ecosystem.
- Sources of eutrophication: Eutrophication can be caused by both natural and human-induced factors. Natural sources include weathering of rocks and soil erosion, while human-induced sources include agricultural runoff, wastewater discharge, and fertilizer application.
- Effects of eutrophication: Eutrophication can lead to harmful algal blooms, which can produce toxins that are harmful to humans and aquatic life. It can also lead to hypoxic conditions, where there is a lack of oxygen in the water, resulting in fish kills and other negative impacts on aquatic life.
- Prevention and control of eutrophication
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8.6 |
Thermal Pollution |
- Thermal pollution refers to the increase or decrease in temperature of water bodies, which can occur due to human activities. This can have significant impacts on aquatic ecosystems, including changes in dissolved oxygen levels, nutrient availability, and the distribution of aquatic organisms.
- The impacts of thermal pollution can include reduced oxygen levels in the water, which can lead to fish kills and other disruptions to aquatic ecosystems.
- Management strategies for thermal pollution
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8.7 |
Persistent Organic Pollutants (POPs) |
- Persistent Organic Pollutants (POPs) are toxic chemicals that are released into the environment, often through human activities such as industrial processes and agriculture. They are highly resistant to degradation and can persist in the environment for many years, even traveling long distances through air and water. Examples of POPs include PCBs (polychlorinated biphenyls), dioxins, and certain pesticides.
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8.8 |
Bioaccumulation and Biomagnification |
- Bioaccumulation: This process refers to the buildup of pollutants or toxins in an organism’s tissues over time. Organisms can absorb pollutants from their environment, such as water or air, through ingestion or absorption. Once absorbed, these pollutants can accumulate in the organism’s tissues, and the concentration of the pollutant can increase as it moves up the food chain.
- Biomagnification: This process refers to the increasing concentration of pollutants or toxins as they move up the food chain. As predators eat prey, they accumulate the pollutants or toxins that are present in their prey’s tissues. The concentration of these pollutants can increase as the predator eats more prey, leading to a higher concentration of pollutants in their tissues.
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8.9 |
Solid Waste Disposal |
- Solid Waste Disposal refers to the management and disposal of solid waste materials, such as trash, garbage, and other refuse generated by human activities.
- Landfills: Landfills are designated areas where solid waste is dumped and buried. They are lined with barriers to prevent contamination of groundwater and other environmental impacts.
- Incineration: Incineration is the process of burning solid waste to reduce its volume and weight. It can generate energy in the form of heat and electricity, but also releases pollutants into the air.
- Recycling: Recycling is the process of converting waste materials into new products. This can help to reduce the amount of waste that ends up in landfills or incinerators.
- Hazardous Waste: Hazardous waste refers to waste materials that are dangerous or potentially harmful to human health or the environment. They require special handling and disposal procedures.
- E-waste: E-waste refers to electronic waste, such as old computers, cell phones, and other electronic devices. These items contain hazardous materials and require special handling and disposal procedures.
- Waste Reduction: Waste reduction refers to efforts to reduce the amount of waste generated in the first place. This can include practices such as composting, using reusable products, and avoiding single-use items.
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8.10 |
Waste Reduction Methods |
- Source Reduction: Source reduction or waste prevention is the practice of designing, manufacturing, using, and consuming products in a way that reduces the amount of waste generated. It includes practices like reusing and recycling, but emphasizes on preventing waste in the first place.
- Recycling: Recycling is the process of converting waste materials into new products to prevent the waste of potentially useful materials. This process involves collecting, sorting, cleaning, and processing materials such as paper, plastics, glass, and metals into raw materials for manufacturing new products.
- Composting: Composting is the process of converting organic waste, such as food scraps and yard waste, into nutrient-rich soil by breaking down the waste through a natural process of decomposition. This process not only reduces waste, but also produces a valuable product for gardening and agriculture.
- Energy Recovery: Energy recovery involves the use of waste materials as a fuel source to produce electricity, heat, or other forms of energy. This process can reduce the amount of waste going to landfills while also providing an alternative energy source.
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8.11 |
Sewage Treatment |
- Sewage Treatment: Sewage treatment is the process of removing contaminants from wastewater, primarily from household sewage.
- Stages of Sewage Treatment:
- Primary Treatment: Primary treatment involves the physical separation of large solids and materials from wastewater using screens and sedimentation tanks.
- Secondary Treatment: Secondary treatment involves biological processes to remove organic matter and nutrients from wastewater. The most common method is the activated sludge process.
- Tertiary Treatment: Tertiary treatment involves advanced processes to remove remaining contaminants such as nitrogen and phosphorus. Methods include filtration, disinfection, and nutrient removal.
- Sludge Treatment: Sludge treatment involves the processing and disposal of the solid material removed during sewage treatment. Methods include digestion, dewatering, and land application.
- Disinfection: Disinfection is the process of killing harmful microorganisms in treated wastewater before it is released into the environment. Common disinfection methods include chlorination, ultraviolet light, and ozone treatment.
- Water Reuse: Water reuse is the practice of treating and reusing wastewater for non-potable purposes such as irrigation, industrial processes, and toilet flushing.
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8.12 |
Lethal Dose 50% (LD50) |
- Lethal Dose 50% (LD50) is a measure of toxicity that represents the dose of a substance required to kill 50% of a population of test animals under specific conditions. The LD50 value is typically expressed in milligrams of substance per kilogram of body weight, and it is used to compare the relative toxicity of different substances.
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8.13 |
Dose Response Curve |
- Dose-response curve is a graphical representation of the relationship between the dose or concentration of a substance and the response or effect it produces in an organism. The response can be a beneficial or adverse effect, and it can be measured in different ways, such as mortality, morbidity, growth, reproduction, behavior, or biochemical markers. The shape of the dose-response curve can vary depending on the nature of the substance and the organism, and it can be used to determine the toxicity, potency, efficacy, and safety of the substance.
- Threshold: The minimum dose or concentration at which a response or effect is first observed.
- Maximum response: The highest level of response or effect that can be achieved.
- ED50: The effective dose that produces a response or effect in 50% of the exposed population.
- LD50: The lethal dose that causes death in 50% of the exposed population.
- NOAEL: The no-observed-adverse-effect level, which is the highest dose or concentration that does not produce any significant adverse effects.
- LOAEL: The lowest observed-adverse-effect level, which is the lowest dose or concentration that produces any significant adverse effects.
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8.14 |
Pollution and Human Health |
- Air Pollution: Air pollution can cause respiratory problems, heart disease, and stroke. It can also cause cancer and birth defects.
- Water Pollution: Contaminated water can cause diseases such as cholera and typhoid. It can also lead to skin problems and other health issues.
- Soil Pollution: Soil pollution can lead to contaminated crops, which can cause health problems when consumed. It can also cause skin problems and other health issues.
- Toxic Substances: Exposure to toxic substances, such as lead, mercury, and pesticides, can cause serious health problems, including brain damage, cancer, and birth defects.
- Environmental Health: Environmental health refers to the study of how environmental factors, such as pollution, affect human health. It includes the study of air quality, water quality, and soil quality, as well as the impact of climate change on human health.
- Health Disparities
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8.15 |
Pathogens and Infectious Diseases |
- Pathogens: They are organisms or agents that cause disease, including bacteria, viruses, fungi, and parasites.
- Infectious diseases: These are diseases caused by pathogens that can spread from one individual to another through direct or indirect contact. Examples of infectious diseases include tuberculosis, measles, and COVID-19.
- Transmission modes: The different ways in which infectious diseases can spread from one individual to another. These include:
- direct contact
- droplets
- indirect contact
- Vectors: These are organisms, such as mosquitoes and ticks, that can transmit diseases from one individual to another.
- Disease outbreaks
- Epidemiology: It is the study of the distribution and determinants of disease in populations.
- One Health
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