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Questions and Answers
What is the effect of chlorinated parabens on wastewater treatment plants?
What is the effect of chlorinated parabens on wastewater treatment plants?
Which chemical is known to act as a mimic of estrogen and disrupt endocrine function?
Which chemical is known to act as a mimic of estrogen and disrupt endocrine function?
How do persistent organic pollutants (POPs) affect thyroid function?
How do persistent organic pollutants (POPs) affect thyroid function?
What role do thyroid hormones play in early development?
What role do thyroid hormones play in early development?
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What is the function of an antagonist in biochemistry?
What is the function of an antagonist in biochemistry?
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Which of the following chemicals is a known endocrine disruptor affecting thyroid systems?
Which of the following chemicals is a known endocrine disruptor affecting thyroid systems?
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What is the potential impact of increased ester chain length in parabens?
What is the potential impact of increased ester chain length in parabens?
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What is a common consequence of exposing laboratory animals to Triclosan?
What is a common consequence of exposing laboratory animals to Triclosan?
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What is a major consequence of increased atmospheric carbon dioxide on ocean chemistry?
What is a major consequence of increased atmospheric carbon dioxide on ocean chemistry?
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How much did the pH of the oceans decrease between 1751 and 1996?
How much did the pH of the oceans decrease between 1751 and 1996?
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Which group of organisms is particularly affected by ocean acidification due to its impact on calcium carbonate?
Which group of organisms is particularly affected by ocean acidification due to its impact on calcium carbonate?
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What significant finding did WWF's 2014 Living Planet Report reveal about wildlife populations?
What significant finding did WWF's 2014 Living Planet Report reveal about wildlife populations?
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Which substance forms when carbon dioxide dissolves in water and contributes to ocean acidification?
Which substance forms when carbon dioxide dissolves in water and contributes to ocean acidification?
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What is the average annual decline of ozone observed since the 1970s?
What is the average annual decline of ozone observed since the 1970s?
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Who first discovered the ozone hole and in what year?
Who first discovered the ozone hole and in what year?
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Which substance is identified as a major source of ozone depletion?
Which substance is identified as a major source of ozone depletion?
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What is the expected recovery period for holes in polar regions if Ozone Depleting Substances are no longer released?
What is the expected recovery period for holes in polar regions if Ozone Depleting Substances are no longer released?
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What is a significant harmful effect of increased UV-B radiation due to ozone depletion?
What is a significant harmful effect of increased UV-B radiation due to ozone depletion?
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Which component is NOT a contributor to photochemical smog?
Which component is NOT a contributor to photochemical smog?
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What causes the majority of photochemical smog production?
What causes the majority of photochemical smog production?
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What type of compounds result from incomplete combustion of carbon-based fuels?
What type of compounds result from incomplete combustion of carbon-based fuels?
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What was the targeted reduction of SO2 emissions in the 1990 amendments to the Acid Deposition Act?
What was the targeted reduction of SO2 emissions in the 1990 amendments to the Acid Deposition Act?
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Which gas is primarily responsible for the increase in global warming since the industrial revolution?
Which gas is primarily responsible for the increase in global warming since the industrial revolution?
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What is the Global Warming Potential (GWP) of CO2 considered to be?
What is the Global Warming Potential (GWP) of CO2 considered to be?
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What percentage of anthropogenic greenhouse gas emissions is attributed to livestock?
What percentage of anthropogenic greenhouse gas emissions is attributed to livestock?
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What major factor contributes to global dimming since the 1950s?
What major factor contributes to global dimming since the 1950s?
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By what percentage did SO2 emissions drop in the US since 1990?
By what percentage did SO2 emissions drop in the US since 1990?
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What event was significantly impacted by pollution-driven artificial clouds according to the content?
What event was significantly impacted by pollution-driven artificial clouds according to the content?
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What is one consequence if pollutant aerosols are cleaned from the atmosphere while greenhouse emissions continue?
What is one consequence if pollutant aerosols are cleaned from the atmosphere while greenhouse emissions continue?
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What is the primary health risk associated with PM2.5 particles?
What is the primary health risk associated with PM2.5 particles?
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Which historical incident is noted for causing numerous deaths due to air pollution?
Which historical incident is noted for causing numerous deaths due to air pollution?
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What was the estimated number of deaths worldwide due to PM2.5 in 2015?
What was the estimated number of deaths worldwide due to PM2.5 in 2015?
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What is the primary source of acidity in acid rain?
What is the primary source of acidity in acid rain?
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How much does complete cessation of fossil fuel emissions potentially increase life expectancy, according to estimates?
How much does complete cessation of fossil fuel emissions potentially increase life expectancy, according to estimates?
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What was the reported number of premature mortalities in India attributed to PM2.5 exposure in 2011?
What was the reported number of premature mortalities in India attributed to PM2.5 exposure in 2011?
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What were the total deaths reported in Europe due to PM2.5 in 2012?
What were the total deaths reported in Europe due to PM2.5 in 2012?
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What is the typical pH level of natural rain?
What is the typical pH level of natural rain?
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What characterizes halogen bonds in the context of protein-ligand interactions?
What characterizes halogen bonds in the context of protein-ligand interactions?
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What is the cocktail effect in toxicology?
What is the cocktail effect in toxicology?
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Which of the following statements about epigenetics is true?
Which of the following statements about epigenetics is true?
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Which substance would likely lead to thyroid health problems?
Which substance would likely lead to thyroid health problems?
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What consequence can result from high concentrations of pesticides in soil?
What consequence can result from high concentrations of pesticides in soil?
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Which epigenetic modification is commonly discussed?
Which epigenetic modification is commonly discussed?
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What is a significant limitation in understanding the cocktail effect?
What is a significant limitation in understanding the cocktail effect?
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Which of the following is NOT a symptom related to thyroid health problems?
Which of the following is NOT a symptom related to thyroid health problems?
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What can contribute to a change in gene expression without altering the gene sequence?
What can contribute to a change in gene expression without altering the gene sequence?
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What is primarily studied in the context of organochlorine and organophosphorus pesticides?
What is primarily studied in the context of organochlorine and organophosphorus pesticides?
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What is a common feature of charge-transfer bonds involving halogens in biology?
What is a common feature of charge-transfer bonds involving halogens in biology?
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What best describes the relationship between epigenetics and genetic inheritance?
What best describes the relationship between epigenetics and genetic inheritance?
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Which of the following is a potential health impact of pesticide toxicity?
Which of the following is a potential health impact of pesticide toxicity?
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Study Notes
Parabens
- Found in about half of personal care products
- Released heavily from wastewater effluents
- Chlorinated parabens are difficult to remove from wastewater treatment plants (WWTPs)
- Endocrine disrupting potential increases with longer ester chains
- Harmful to aquatic life
Polyfluorinated Organic Substances (PFOS)
- Extremely persistent
- Absorbed in the body, increasing cell permeability
- Some are endocrine disruptors (e.g., affecting the thyroid)
Other Ubiquitous Anthropogenic Chemicals
- Methyl-tert-butyl ether (MTBE): Affects the nervous system and can cause cancer (effects depend on the dose).
- Alkyl Phenols (e.g., Nonylphenol): Mimics estrogen hormone, an endocrine disruptor.
- Bisphenol-A (BPA): Used in plastic production, has high endocrine disrupting chemical (EDC) activity at very low doses.
Chemical Structure of PFOS and PFOA
- Both are perfluorinated compounds (PFCs)
- PFOA and PFOS are thyroid hormone disruptors
- They lack structural similarity to thyroid hormones
Thyroid Gland and Hormones
- Thyroid glands regulate the production and balance of thyroid hormones
- Crucial for brain development in babies during prenatal stages and early years
- Several persistent organic pollutants (POPs), with similar structures to PCBs and dioxins, impair thyroid function by:
- Impairing iodine uptake by the gland
- Blocking hormone production enzymes
- Displacing natural hormones in blood proteins, affecting distribution and entry
Iodine Deficiency
- Global statistics on iodine deficiency are documented in WHO 2004.
- Levels are categorized as: Severe, Moderate, Mild, Optimal, Risk of iodine induced hyperthyroidism, and Risk of Adverse consequences (Based on median UI values).
Agonist/Antagonist
- Agonist: Endogenous or exogenous chemical that binds to a specific receptor, activating the receptor and producing a biological response.
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Antagonist: Chemical that blocks the biological response or activity of an agonist by binding to and blocking the target receptor (also called a "blocker").
- Example: Triclosan, a common antibacterial agent, can disrupt thyroid systems in lab animals, potentially through agonist or antagonist pathways involving specific nuclear receptors regulating catabolic and transport activity.
- Triclosan may be an estrogen or androgen receptor antagonist (or a weak agonist).
Deiodinase Enzymes
- All deiodinase enzymes are selenoenzymes, meaning they contain selenium
Mercury
- Organic mercury (e.g., methyl or ethyl mercury) can be converted to inorganic mercury by microorganisms in the intestines
- Inorganic mercury can persist in the brain for long periods.
- Inorganic mercury interacts with selenium, forming mercury selenite (HgSe), which is thought to accumulate in the central nervous system
- Cadmium has similar interactions with selenium
Structural Comparison of Endocrine Disruptors (EDCs) to Thyroid Hormones
- All EDCs share strong structural homology with thyroid hormones (like T4)
- BPA is formed when TBBPA breaks down in the environment
Triclosan
- Antibacterial agent; commonly found in various products
- Banned by FDA in US for some applications (for antiseptic washes).
- Weak endocrine disruptor and allergen.
- Similar to Triclocarban, another antibacterial agent
Halogen Bonds
- Both chlorine and iodine in Triclosan and Triiodothyronine can form halogen bonds.
- Halogen bonds are strong, directional, and lead to specific binding angles in interactions (e.g. protein-ligand interactions).
- These bonds often involve polarizable halogens which interact with carbonyl or hydroxyl groups of amino acids.
Cocktail Effect
- Four chemicals tested individually below LD50 may have no harmful effect
- But when tested in combination at the same doses, they have harmful effects
Epigenetics
- Environmental factors affect gene function by activating or deactivating genes without changing the gene sequence.
- These epigenetic changes can be passed down to the next generation if the environmental factors persist.
- DNA methylation and histone modification alter gene expression without changing the underlying DNA sequence (affects how genes are read)
Air Pollution
- Ozone Depletion: Stratospheric ozone layer is declining globally at approximately 4% per decade; localized depletion, known as "ozone holes," can reach 65% of the ozone layer; - The Ozone layer shields Earth from harmful ultraviolet radiation. - Ozone depleting substances (ODS) such as CFCs, are major contributors to this issue and are responsible for increased concentrations of UV radiation reaching Earth.
- Photochemical Smog: Consists of various pollutants including aldehydes, nitrogen oxides, peroxyacetyl nitrates (PAN), volatile organic compounds, and heavy metals formed from fuel and coal burning; harmful to eyes, throat, and the respiratory systems, impacting agriculture.
- Particulate Matter (PM): Microscopic/sub-microscopic solid/liquid particles suspended in the air; causes climate and rain pattern issues, and harmful health outcomes (e.g. lung problems, exposure); sources include industries, construction sites, vehicles, and wildfires.
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Acid Rain: Acid rain is caused by the release of sulfur dioxide (SO₂) and nitrogen oxides (NOx). These gases react with water in the atmosphere to create sulfuric and nitric acids that fall to the ground with the rain. This lowers the pH of rain, increasing acidity.
- Acid rain affects both human and environmental health. Sources of these gases include fossil fuels burning. - Steps were, and continue to be taken, to reduce SO₂ emissions to mitigate the effects of acid rain.
Global Warming and Dimming
-
Global Warming: Increase in average earth temperature due to increased greenhouse gases, particularly CO2.
- CO2 concentrations have risen from 280 ppm to 400 ppm since the Industrial Revolution, primarily from the burning of fossil fuels (coal, oil, natural gas). - Many other anthropogenic gases also contribute to global warming (include N2O, CFCs, etc.) -
Global Dimming: Gradual decline in the amount of global direct solar radiation due to aerosols (e.g., industrial dust).
- Causes disruptions in weather patterns.
Ocean Acidification
- Dissolved atmospheric CO₂ forms carbonic acid in oceans, leading to increased acidity
- Impacts calcifying organisms like corals and shellfish as decreasing pH compromises minerals needed to create shells
Multi-Faceted Environmental Alterations
- WWF's Living Planet Index (LPI) shows significant population declines (birds, reptiles, mammals, amphibians and fish) by 52% since 1970. Insect declines are also notable.
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Description
This quiz explores the effects of chlorinated parabens, persistent organic pollutants, and other chemicals known to disrupt endocrine function. Test your knowledge on the role of thyroid hormones in development and the implications of exposure to various disruptors. Gain insights into biochemistry and environmental health.
