Untitled Document PDF - Environmental Science

1. What information can you find in a MSDS? An MSDS (Material Safety Data Sheet) provides essential information about chemical substances, including: ​ Chemical identity (name, formula, CAS number) ​ Hazards identification (fire, reactivity, toxicity) ​ Safety precautions (handling,...

1. What information can you find in a MSDS? An MSDS (Material Safety Data Sheet) provides essential information about chemical substances, including: ​ Chemical identity (name, formula, CAS number) ​ Hazards identification (fire, reactivity, toxicity) ​ Safety precautions (handling, storage, and disposal instructions) ​ Personal protective equipment (PPE) requirements ​ First aid measures and emergency response ​ Fire-fighting instructions (e.g., suitable extinguishing media) 2. Why must students consult the MSDS of the chemical substances they will work on in a laboratory experiment? Students need to consult the MSDS to: ​ Understand risks associated with the chemicals (e.g., toxic effects) ​ Know emergency procedures, including first aid and spill response ​ Learn proper handling and storage to prevent accidents ​ Ensure compliance with safety regulations and use of PPE 3. Define “Food Chain” A food chain shows the transfer of energy and nutrients through different levels of organisms in an ecosystem. ​ Producers (plants, algae) capture energy from the sun. ​ Primary consumers (herbivores) eat producers. ​ Secondary and tertiary consumers (carnivores) eat other animals. ​ Decomposers break down dead organisms and recycle nutrients. 4. Define Toxicology Toxicology is the study of the harmful effects of chemicals on living organisms. It includes: ​ Identifying toxic substances ​ Understanding exposure pathways (inhalation, ingestion, absorption)  ​ Determining safe exposure levels ​ Developing treatments for poisonings 5. What is a “hazard”? A hazard is any situation or substance that can cause harm or damage to: ​ Human health (e.g., exposure to toxic chemicals) ​ Property (e.g., fire hazards) ​ The environment (e.g., chemical spills) 6. What is a “risk”? Risk is the probability that a hazard will cause harm under specific circumstances. It involves: ​ Exposure to the hazard ​ Severity of consequences if harm occurs​ For example, a chemical may be hazardous but pose low risk if handled with proper precautions. 7. “Risks are usually expressed as probabilities.” What does this statement mean? This statement means that risk is quantified in terms of likelihood that harm will occur.​ Example: ​ If a chemical has a 1 in 1,000 chance of causing injury per exposure, the risk is expressed as 0.1%. 8. A person working near a busy roadway is exposed to what kind of hazards? Hazards include: ​ Air pollution (vehicle emissions like carbon monoxide, nitrogen oxides) ​ Noise pollution (which can cause hearing loss or stress) ​ Physical hazards (e.g., risk of accidents)  ​ Long-term health risks (respiratory diseases from prolonged exposure to pollutants) 9. What is a carcinogen? A carcinogen is a substance or agent that can cause cancer by: ​ Damaging DNA ​ Disrupting cell growth and division​ Examples: Asbestos, benzene, and tobacco smoke. 10. What is a teratogen? A teratogen is a substance that can cause birth defects by interfering with fetal development.​ Examples: Alcohol, thalidomide, and certain medications. 11. What is a neurotoxin? A neurotoxin is a substance that disrupts or damages the nervous system, leading to: ​ Nerve damage ​ Muscle weakness, cognitive impairment​ Examples: Lead, mercury, and pesticides. 12. How does a toxin enter the food chain? Toxins enter the food chain through: ​ Pollutants absorbed by producers (e.g., plants, algae) ​ Bioaccumulation in herbivores and predators as they consume contaminated food​ Example: Methylmercury builds up in fish and is passed on to humans. 13. How do bushfires impact the environment? Bushfires can: ​ Destroy habitats and biodiversity  ​ Cause soil erosion and loss of nutrients ​ Release large amounts of carbon dioxide and other pollutants ​ Disrupt ecosystems and food chains 14. What are some symptoms of lead poisoning? Symptoms include: ​ Abdominal pain, headaches, fatigue ​ Memory loss, irritability, and difficulty concentrating ​ Developmental delays and learning difficulties in children 15. What fish species (commercial) are found to have mercury contamination? Common species include: ​ Tuna ​ Swordfish ​ King mackerel ​ Shark 16. In what form is mercury found in aquatic animals? Mercury is found as methylmercury, a highly toxic compound that accumulates in fish tissues through the food chain. 17. What is DDT? DDT (dichlorodiphenyltrichloroethane) is a synthetic insecticide used to control pests but banned in many countries due to: ​ Environmental persistence ​ Bioaccumulation ​ Toxic effects on wildlife 18. What is the connection between Rachel Carson and DDT? Rachel Carson's book Silent Spring exposed the environmental damage caused by DDT, leading to: ​ Public awareness of its dangers ​ Policy changes and bans on its use in many countries 19. Where is BPA found (household)? BPA (bisphenol A) is found in: ​ Plastic containers and water bottles ​ Food can linings ​ Thermal paper receipts 20. What are some alternatives to BPA? Alternatives include: ​ BPA-free plastics ​ Glass, stainless steel, and silicone containers ​ Polymers such as polyethylene and polypropylene 21. What is LD50? LD50 (Lethal Dose 50%) is the dose of a substance that causes death in 50% of a test population. It is a measure of toxicity. 22. What is a “Persistent Organic Pollutant”? Persistent Organic Pollutants (POPs) are toxic compounds that: ​ Resist degradation ​ Accumulate in living organisms ​ Travel long distances through air and water​ Examples: DDT, dioxins, and PCBs. 23. What is an “acute effect”? An acute effect is a sudden and severe reaction to exposure to a toxic substance, such as: ​ Difficulty breathing ​ Dizziness, nausea, or vomiting 24. What is the “Precautionary Principle”? The precautionary principle suggests taking preventive action when: ​ There is scientific uncertainty about potential risks.​ Example: Limiting the use of a new chemical until its safety is confirmed.