Water Pollution (Cambridge (CIE) IGCSE Environmental Management): Flashcards
Exam code: 0680
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Define water pollution.
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Cards in this collection (55)
Define water pollution.
Water pollution occurs when substances enter rivers, lakes, groundwater or oceans and make the water unsafe for drinking, farming, fishing or wildlife.
How can toxic chemicals in detergents affect a river?
Toxic chemicals in detergents can kill fish or contaminate drinking water.
Medicines, shampoos and cosmetics flushed down drains add chemicals and that can affect fish reproduction.
Medicines, shampoos and cosmetics flushed down drains add chemicals and hormones that can affect fish reproduction.
What do cooking oils washed down sinks do to water?
Cooking oils form greasy layers on water surfaces and can clog drainage systems.
Define biological oxygen demand (BOD).
Biological oxygen demand (BOD) is a measure of how much oxygen microorganisms need to break down organic waste in water.
True or False?
Untreated sewage in a river can spread disease-causing bacteria and viruses.
True.
Sewage contains pathogens, so people who wash in or drink the water can catch diseases such as cholera.
Why can a high BOD kill fish?
A high BOD makes oxygen levels drop, so fish can suffocate.
Plastic bags, bottles and packaging take of years to break down.
Plastic bags, bottles and packaging take hundreds of years to break down.
How can plastic waste kill wildlife?
Wildlife may mistake plastic for food, which can block the digestive system and cause death.
Define microplastics.
Microplastics are tiny pieces of plastic, formed when larger plastics break apart, that aquatic organisms can ingest.
True or False?
Warm water holds more dissolved oxygen than cool water.
False.
Warmer water holds less oxygen, which stresses fish.
Define thermal pollution.
Thermal pollution is the warming of a water body by warm water released from industrial cooling systems.
Which two heavy metals from factories can poison aquatic life?
Mercury and lead are toxic heavy metals that can poison aquatic life.
Fertiliser run-off adds nitrates and phosphates to water, which causes algae growth and can lead to .
Fertiliser run-off adds nitrates and phosphates to water, which causes algae growth and can lead to eutrophication.
Which organisms can pesticide run-off poison?
Pesticide run-off can poison aquatic insects, fish and other wildlife.
How does animal waste from farms reduce water quality?
Animal waste washing into rivers increases bacteria levels in the water.
What type of pathogen is Vibrio cholerae, the cause of cholera?
Vibrio cholerae is a bacterium.
True or False?
Cholera spreads mainly through mosquito bites.
False.
Cholera spreads when people drink or use untreated water contaminated with sewage.
Severe diarrhoea from cholera makes the body lose large amounts of water and , so tissues and organs stop working properly.
Severe diarrhoea from cholera makes the body lose large amounts of water and ions, so tissues and organs stop working properly.
Where is cholera most common?
Cholera is most common where sewage systems are poor or after floods mix human waste with drinking water.
Define bioaccumulation.
Bioaccumulation is the gradual build-up of a toxic substance in a single organism over time.
Why does bioaccumulation happen?
Bioaccumulation happens because organisms absorb toxins faster than they can remove them.
Define biomagnification.
Biomagnification is the increase in the concentration of a toxin as it passes up the food chain.
Why do predators build up more of a toxin than their prey?
Predators build up more toxin because they eat many contaminated organisms.
True or False?
The insecticide DDT breaks down quickly once it reaches waterways.
False.
DDT is persistent, so it keeps accumulating in animals at higher trophic levels, such as birds of prey.
How did DDT affect birds of prey?
DDT caused thinning of eggshells and reduced reproductive success in birds of prey.
What damage does mercury from industry cause in humans and wildlife?
Mercury causes nerve damage and serious health problems in humans and wildlife.
Acid rain forms when sulfur dioxide and from burning fossil fuels mix with rainwater.
Acid rain forms when sulfur dioxide and nitrogen oxides from burning fossil fuels mix with rainwater.
True or False?
Acid rain raises the pH of rivers and lakes.
False.
Acid rain lowers the pH of water, and many fish and aquatic insects cannot survive in acidic conditions.
How does acid rain harm fish directly?
Acid rain damages fish gills and kills fish eggs.
Which toxic metal can acid rain leach from soil into rivers?
Acid rain can leach aluminium from the soil into rivers and lakes.
Define leaching of nutrients.
Leaching is when rainwater dissolves nitrates and phosphates from fertilisers and carries them into rivers and lakes.
What do excess nutrients in a lake first lead to?
Excess nutrients first lead to algal blooms, a rapid growth of algae.
Algae cover the water surface and block , so aquatic plants below cannot photosynthesise and die.
Algae cover the water surface and block sunlight, so aquatic plants below cannot photosynthesise and die.
Why do oxygen levels fall during eutrophication?
Oxygen levels fall because decomposers use up oxygen as they break down dead plants and algae.
True or False?
Eutrophication increases biodiversity in rivers and lakes.
False.
Eutrophication creates low-oxygen (hypoxic) water, which can cause ecosystem collapse and loss of biodiversity.
Define improved sanitation.
Improved sanitation is the use of facilities that separate human waste from human contact, which reduces the spread of pathogens into water sources.
How do flush toilets protect wells and streams?
Flush toilets connect to safe sewage systems that move waste away from homes, so less waste contaminates wells and streams.
True or False?
Composting toilets use large volumes of water to flush waste away.
False.
Composting toilets use dry material to break down waste into compost, so they reduce water use.
Where are sealed pit latrines most suitable?
Sealed pit latrines suit places where no sewer network exists.
Good sanitation prevents diseases such as cholera, and diarrhoea.
Good sanitation prevents diseases such as cholera, dysentery and diarrhoea.
Define sewage treatment.
Sewage treatment is the process of removing solids, organic matter, nutrients and pathogens from wastewater so the water can safely return to the environment or go back into use.
What is the purpose of primary treatment of sewage?
Primary treatment removes large solid materials and some suspended solids from wastewater.
What does a comminutor do in primary treatment?
A comminutor grinds up remaining large solids to prevent pipe blockages.
During primary treatment, workers or machinery remove floating grease and oil by the water surface.
During primary treatment, workers or machinery remove floating grease and oil by skimming the water surface.
True or False?
Secondary treatment removes all nutrients and pathogens from wastewater.
False.
After secondary treatment, water may still contain some nutrients, such as nitrates and phosphates, and pathogens; tertiary treatment removes these.
Why do treatment plants pump oxygen into wastewater in secondary treatment?
Pumping in oxygen encourages bacteria to break down organic pollutants, such as human waste and food.
Define activated sludge.
Activated sludge is sludge containing aerobic bacteria that decompose organic matter; plants reuse part of it in the aeration tank.
Which two methods disinfect water in tertiary treatment?
Tertiary treatment uses chlorine or ultraviolet (UV) light to kill pathogens.
Why does tertiary treatment remove nitrogen and phosphorus?
Tertiary treatment removes nitrogen and phosphorus because they can cause eutrophication if released into water bodies.
Define effluent.
Effluent is treated water that is clean enough to discharge safely into rivers and lakes or to reuse.
Which type of fuel helps power stations produce less sulfur dioxide?
Burning low-sulfur fossil fuels produces less sulfur dioxide during combustion.
Legislation may require companies to the pollutant levels in their factory emissions or wastewater discharge.
Legislation may require companies to measure the pollutant levels in their factory emissions or wastewater discharge.
True or False?
A company that exceeds its legal pollutant limits can only receive a warning.
False.
The company can face fines or legal penalties, and in extreme cases prosecution or forced closure.
Which incentives can governments offer organisations that reduce pollutant emissions?
Governments can offer grants or tax relief to organisations that reduce pollutant emissions.
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