unit 8 pt.2 Flashcards
(20 cards)
Explain the oxygen sag curve in polluted streams and its biological impact.
DO drops downstream due to bacteria using oxygen to break down waste; harms fish.
Why are lakes more vulnerable to pollution compared to rivers?
Lakes have less mixing and flow, so pollution builds up more easily.
How does cultural eutrophication lead to hypoxic zones?
Too many nutrients → algae → bacteria decompose it → oxygen drops.
What is the role of aerobic bacteria in secondary sewage treatment?
They eat organic waste, lowering BOD in sewage treatment.
How do POPs move through the food web and affect top predators?
POPs build up in fat and magnify up the food chain; harm top predators.
Why is groundwater contamination often irreversible?
Groundwater moves slowly, so pollution stays for decades or longer.
Describe the difference between primary, secondary, and tertiary sewage treatment.
Primary: solids out. Secondary: bacteria clean. Tertiary: chemicals remove nutrients.
What are the main ecological risks of thermal pollution in aquatic ecosystems?
Warmer water = less oxygen + more stress on aquatic life.
Why does the Ogallala Aquifer have such a slow recharge rate?
It’s deep, old water with little rainfall or soil that lets water in.
What are the pros and cons of using bioremediation to clean oil spills?
Good for nature, but slow and doesn’t work well in poor conditions.
What factors influence porosity and permeability in soil during landfill investigations?
Porosity = space between particles. Permeability = how easily water flows.
How does the structure of confined aquifers protect water quality?
Protected by layers above = less pollution risk.
What mechanisms contribute to saltwater intrusion in coastal aquifers?
Too much pumping lowers pressure, so saltwater moves into aquifers.
What are the major environmental trade-offs of large dam construction?
Helps water supply and power but destroys habitats and displaces people.
Explain how greywater reuse helps reduce strain on municipal water systems.
Cuts demand for clean water by reusing safe household water.
Why do estuaries like Chesapeake Bay face higher risk of eutrophication?
Estuaries collect runoff + nutrients, making them prone to algae blooms.
How can arsenic naturally enter groundwater supplies, and where is this most common?
Arsenic leaks from bedrock; big issue in Bangladesh, India, parts of U.S.
Explain how combined sewer overflows occur and why they’re a public health risk.
Old systems overflow during rain, dumping raw sewage into waterways.
What is the importance of Natural Resource Damage Assessment (NRDA) after oil spills?
NRDA tracks damage after spills and makes polluters pay for cleanup.
How can nutrient trading policies help reduce water pollution from agriculture?
Farms can buy/sell credits to reduce nutrient runoff more efficiently.
