Comprehensive Study Notes on Biomagnification and Waste Management

8.8 Biomagnification

Overview of Biomagnification

  • Definition: Biomagnification is the increase in concentration of substances per unit of body tissue that occurs in successively higher trophic levels of a food chain or food web.

Suggested Skill 4.A - Scientific Experiments

  • Purpose: Identify a testable hypothesis or scientific question for an investigation.

Learning Objectives and Essential Knowledge for STB-3.1: Bioaccumulation and Biomagnification

Learning Objective STB-3.1: Describe bioaccumulation and biomagnification.

Essential Knowledge

  • STB-3.1.1: Bioaccumulation

    • Definition: Bioaccumulation is the selective absorption and concentration of elements or compounds by cells in a living organism, most commonly observed with fat-soluble compounds.

  • STB-3.1.2: Biomagnification

    • Description: Biomagnification refers to how the concentration of substances increases at each successive trophic level due to the consumption of organisms that have bioaccumulated these substances.

Effects of Bioaccumulation and Biomagnification

  • STB-3.J: Describe the effects of bioaccumulation and biomagnification.

    • STB-3.J.1: Ecosystem effects include:

    • Eggshell thinning in birds due to DDT.

    • Developmental deformities in higher trophic level carnivores.

    • STB-3.J.2: Human health impacts:

    • Harmful effects include neurological, reproductive, and circulatory system issues.

    • STB-3.J.3: Examples of substances:

    • DDT, mercury, and PCBs have significant environmental impacts.

Bioaccumulation Process

  • Fat-soluble compounds, such as persistent organic pollutants (POPs) and methylmercury, are absorbed and concentrated in the cells and fat tissues of organisms.

    • Since these compounds do not dissolve easily in water, they accumulate in the fat tissues rather than being excreted via urine.

    • This leads to increasing concentrations within the organism over time, contributing to bioaccumulation.

Biomagnification Process

  • Mechanism:

    • Biomagnification starts with the uptake of POPs or methylmercury from sediments or plants (e.g., phytoplankton, grass) in an ecosystem.

    • Primary Consumers (e.g., zooplankton) ingest these compounds by consuming producers, resulting in bioaccumulation in their bodies.

    • Secondary Consumers then eat these primary consumers, accumulating more POPs in their tissues, leading to even higher concentrations due to cumulative dietary intake.

    • The 10% Rule illustrates that organisms must consume more biomass (10 times more) at each trophic level to obtain the same amount of energy, which results in increasingly high concentrations of contaminants over lifetimes.

    • Apex Predators like salmon, dolphins, and whales exhibit the highest levels of POPs and methylmercury.

Case Study: DDT and Biomagnification

  • DDT usage has been banned in many developed nations due to its lasting presence in the environment.

  • It accumulates in the tissues of bottom feeders and zooplankton, subsequently biomagnifying up the food chain, particularly affecting top predators such as predatory birds, causing eggshell thinning and population declines (e.g., the bald eagle).

  • This decline prompted legislation such as the Endangered Species Act of 1973.

Case Study: Methylmercury

  • Methylmercury originates from mercury released from coal combustion and natural sources such as volcanic eruptions, where it is converted into toxic forms by bacteria in aquatic ecosystems.

  • Phytoplankton absorb methylmercury, leading to biomagnification in predators like tuna and sharks, and ultimately affecting human health through seafood consumption.

  • Neurological effects and reproductive system disruption are notable human health risks linked to methylmercury exposure, especially for developing fetuses.

Understanding Long-Term Pollutant Effects

  • Pollutants may not cause immediate animal mortality but can have long-term adverse effects on food webs through bioaccumulation and biomagnification processes.

  • Example of PCBs: These pollutants enter the ocean primarily as industrial waste, absorbed by phytoplankton and propagated through the food web, leading to high concentrations in apex predators like killer whales.

Practice FRQ 8.8

  • Scenario: Scientists suspect that a compound named smedsium, released from bike tires, biomagnifies in aquatic organisms in a nearby lake.

  • Required Task: Identify a testable hypothesis that the scientists may use in their study.

8.9 Solid Waste Disposal

Suggested Skill 7.D - Environmental Solutions

  • Objective: Utilize data and evidence to support potential solutions for waste disposal problems.

Learning Objectives and Essential Knowledge for STB-3.K: Solid Waste Disposal Methods

  • STB-3.K.1: Solid waste definition and sources include domestic, industrial, commercial, and agricultural sectors.

  • STB-3.K.2: Landfills as primary disposal method for solid waste, their potential for groundwater contamination and harmful gas emissions.

  • STB-3.K.3: E-waste defined as discarded electronic devices such as phones, TVs, and computers.

  • STB-3.K.4: Description of a sanitary landfill's components: bottom liner, storm water and leachate collection systems, cap, and methane collection system.

Effects & Issues with Solid Waste Disposal Methods

  • STB-3.L.1: Landfill decomposition factors depend on trash composition and conditions conducive for microbial decomposition.

  • STB-3.L.2: Incineration of waste reduces volume significantly, but involves releases of air pollutants.

  • STB-3.L.3: The illegal disposal of items such as rubber tires raises environmental health concerns, including mosquito breeding grounds.

  • STB-3.L.4: Ocean dumping exacerbates plastic pollution, leading to wildlife entanglement and ingestion issues.

Types and Sources of Solid Waste

  • Municipal Solid Waste (MSW) encompasses household and business waste.

    • E-waste constitutes about 2% of MSW but is hazardous due to metal contents.

  • The waste stream includes recycling, landfills, and incineration; compositions split into approximately 1/3 paper and 2/3 organic materials (compostable).

Sanitary Landfills

  • Sanitary landfills differ from dumps through their engineered features, including:

    • Bottom Liner: prevents pollution leakage.

    • Leachate Collection System: captures fluids draining through waste.

    • Methane Recovery System: collects gases for energy production.

    • Clay Cap: habitat restoration after landfill closure.

Landfill Contents & Decomposition Processes

  • Slow decomposition rates occur due to low oxygen and moisture conditions in landfills.

    • Items unsuitable for landfills include hazardous materials (e.g., antifreeze), metals (e.g., copper), and old tires that foment mosquito breeding.

    • Acceptable landfill items include non-recyclable cardboard, rubber, and plastic wrapping.

Landfill Environmental Impact

  • Landfills can cause significant groundwater contamination from heavy metals and toxic substances in leachate.

  • Greenhouse gases release from decomposition (CO2 and CH4) contribute to climate change.

  • Communities often oppose landfills, especially low-income areas that lack resources to contest placements, resulting in environmental injustice.

Waste Incineration & Ocean Dumping Practices

  • Incineration minimizes landfill requirements but generates air pollutants (e.g., SOx, NOx) and risks toxic material leaching.

  • Ocean dumping, often unmonitored, contributes to large oceanic trash islands and endangers marine life.

Practice FRQ 8.9

  • Task: Propose a federal government policy to decrease landfill waste by 15% using graphical evidence for support.

8.10 Waste Reduction Strategies

Suggested Skill 6.B - Mathematical Routines

  • Objective: Describe changes in practices that could minimize generated waste, outlining benefits and drawbacks.

Essential Knowledge on Waste Reduction Practices

  • Recycling: Process of converting solid waste into new products. It conserves minerals but is energy-intensive.

  • Composting: Organic waste decomposition process; can produce fertilizer, with potential odors and pest issues.

  • E-waste Reduction: Refers to recycling and reuse approaches to handle hazardous electronic waste.

  • Landfill Mitigation: Includes energy recovery methods and transforming old landfill sites into parks.

The Three Rs: Reduce, Reuse, and Recycle

  • Reducing: Most sustainable method; minimizes resource extraction and energy input.

  • Reusing: Next best choice, exemplified by using reusable items to avoid additional production energy.

  • Recycling: The least sustainable of the three; while it lessens new material demand, processing requires significant energy.

Recycling Benefits and Challenges

  • Pros:

    • Minimizes needs for new raw materials, conserving natural habitats.

    • Reduces energy and fossil fuel consumption in product creation.

    • Decreases landfill volume, extending usable landfill space.

  • Cons:

    • Costs associated with recycling processes and fluctuating market prices can lead to waste.

    • Contaminated recycling increases processing costs.

Global Plastic Waste - Disposal Methods Overview

  • Statistics show the proportions of global plastic waste outcomes by disposal method (e.g., recycling, incineration).

Composting Overview

  • Organic matter decomposition with strict aeration conditions improves soil quality.

  • Odor regulation and pest management are critical to successful operations.

E-Waste Management

  • E-waste recycling helps recover valuable metals but often results in hazardous environmental impacts if mismanaged.

Waste-to-Energy Systems

  • Incineration of waste not only reduces waste volumes but can also generate electricity. Methane from landfills can similarly produce energy, promoting sustainable energy solutions.

Practice FRQ 8.10

  • (a) Calculate the percentage increase in mobile device sales (from 30 million in 1998 to 180 million in 2007).

  • (b) Determine the total grams of gold used in devices sold in 2007, based on average device content.

8.11 Sewage Treatment

Suggested Skill - Visual Representations

  • Learning Objective: Describe optimal sewage treatment practices.

Essential Knowledge on Sewage Treatment Procedures

  • Primary Treatment: Physical removal of debris with screening followed by sedimentation of solid waste.

  • Secondary Treatment: Biodegradation of organic matter by aerating tanks with bacteria.

  • Tertiary Treatment: Applications of ecological or chemical techniques to filter remaining pollutants.

Detailed Processes in Sewage Treatment

  • Primary Treatment Processes: Include filtration through screens and removal of grit, sludge formation for further processing.

  • Secondary Treatment Processes: Using bacteria to convert organic matter into less harmful outputs, with oxygenation enhancing efficiency.

  • Tertiary Treatment Needs: Essential for eliminating nitrogen and phosphorus to prevent eutrophication when discharging treated effluent.

Sewage Treatment Challenges

  • Overflow Situations: Systems may fail with heavy rain, releasing untreated sewage.

  • Macrophage Contaminants: Even treated effluents can carry elevated nitrogen and phosphorus, plus persistent endocrine disruptors.

Practice FRQ 8.11

  • Identify and justify a pollutant removal step in the sewage treatment diagram as part of the primary treatment process.

8.12 & 8.13 LD50 and Dose Response Curve

Suggested Skill - Mathematical Routines

  • Learning Objective EIN-3.A: Define lethal dose 50% (LD50).

Essential Knowledge for LD50 & Dose Response Curves

  • LD50 Definition: The dosage of a chemical lethal to 50% of a population.

  • Dose Response Curve: Graphical representation of organism response/mortality related to dose concentration.

    • Independent Variable: Dose concentration of the chemical.

    • Dependent Variable: Biological response (e.g., mortality rate).

  • LD50 Characteristics: Expressed as mass per kg or parts per million (ppm).

  • Dose Response Studies: Involves organisms exposed to varying doses to measure effects; LD50 makes estimating safe exposure levels critical.

Key Aspects of Dose Response Curves

  • Typical S-shape in mortality against dose concentrations; includes a threshold dose point.

  • Differences between acute studies (short-term exposure focus) versus chronic studies (long-term impact assessments).

  • Toxicity studies conducted on mammalian models for understanding human health risks.

Practice FRQ 8.12 & 8.13

  • Analyze polonium (PO) toxicity data, including maximum allowable levels from lab testing and establish thresholds for effect responses.

8.14 Pollution and Human Health

Learning Objective EIN-3.C

  • Identify human health issues associated with pollution.

Essential Knowledge on Pollution and Health Outcomes

  • Establishing causality between pollutants and health issues is challenging due to multifactorial exposure.

  • Specific Health Concerns:

    • Dysentery: Bacterial infection from untreated sewage in waterways.

    • Mesothelioma: Cancer resulting from asbestos exposure, affecting lung lining.

    • Tropospheric Ozone: Elevated concentrations linked to respiratory health deterioration.

Routes of Exposure and Synergism

  • Pathways through which pollutants enter the human body can complicate identification of health effects.

  • Synergistic Effects: The combined impact of multiple substances causing exacerbated health issues.

Health Problems from Specific Pollutants

  • Dysentery: High mortality rates in developing regions due to poor sanitation. Treatment includes antibiotics and hydration.

  • Mesothelioma: Associated with historical use of asbestos; mandates professional removal due to health risks.

  • Tropospheric Ozone: Respiratory impacts from ground-level ozone necessitate pollution control measures.

Practice FRQ 8.14

  • Define a control group in an experiment assessing sewage impact on a drinking water source.

8.15 Pathogens and Infectious Diseases

Suggested Skill 2.B - Visual Representations

  • Explain the cyclic nature of pathogens and their environment interactions.

Essential Knowledge for Infectious Diseases Linked to Pollution

  • Pathogens and Vectors: Defined as organisms (viruses, bacteria, etc.) propagating infections via interactions with other organisms.

    • Adaptation themes highlight the health risks of pathogens leveraging human hosts and climate trends shifting epidemiology.

Specific Infectious Diseases

  • Tuberculosis: Chronic infection targeting lungs, transmitted through respiratory exposure.

  • Malaria: Mosquito-borne infection prevalent in tropical areas; proactive mosquito control measures are necessary for prevention.

  • West Nile Virus: Transmitted via mosquito bites; affects the nervous system.

  • Cholera: Bacterial disease resulting from contaminated water sources; addresses severe dehydration risks.

Practice FRQ 8.15

  • Identify a geographical region likely to experience cholera outbreaks based on historical data assessments.