Bioaccumulation

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Definition of Bioaccumulation

Bioaccumulation is the process by which toxic substances build up in the tissues of organisms over time.
Toxic substances include pesticides, heavy metals (e.g., mercury, lead), and other pollutants.
These toxins enter the environment through air, water, or soil.
Once in an ecosystem, toxins move through the food chain and become more concentrated in animals higher up.

Example: Mercury

Mercury is a heavy metal released from industrial processes like coal burning.
In aquatic ecosystems, mercury is absorbed by plankton.
Small fish eat plankton and accumulate mercury in their bodies.
Larger fish (e.g., tuna, trout) eat smaller fish, increasing mercury concentration.
Top predators (including humans) can have dangerously high mercury levels, leading to neurological disorders.

Example: DDT

DDT was a pesticide used extensively in agriculture.
It accumulated in the environment, especially in aquatic ecosystems.
Small organisms absorbed DDT; it became highly concentrated in birds of prey (e.g., eagles, ospreys).
High DDT levels caused birds to lay eggs with very thin shells, which often broke before hatching.
This led to a significant decline in bird populations, and DDT was banned in many countries.

Preventing Bioaccumulation

Reduce the release of harmful chemicals and pollutants into the environment.
Use less toxic alternatives to pesticides.
Enforce stricter regulations on industrial waste.
Ensure proper disposal of toxic materials.

Key Points

Bioaccumulation leads to higher toxin concentrations in organisms at higher trophic levels.
Human activities (e.g., industry, agriculture) contribute to the release of toxins.
Health risks include neurological disorders (mercury) and reproductive failure (DDT).
NHS advises limiting tuna consumption to 2 steaks per week due to mercury bioaccumulation.

Energy pyramid showing bioaccumulation: toxin concentration increases at higher trophic levels.

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1.What is bioaccumulation?
Easy
- AThe increase in concentration of a toxic substance in the tissues of organisms over time
- BThe breakdown of toxic substances in the environment
- CThe movement of organisms from one habitat to another
- DThe process by which organisms produce toxins
2.Which of the following is an example of a toxic substance that can bioaccumulate?
Easy
- AOxygen
- BWater
- CMercury
- DCarbon dioxide
3.Bioaccumulation occurs when toxic substances build up in which part of an organism?
Easy
- AThe digestive system only
- BThe tissues
- CThe fur or feathers
- DThe external environment
4.A small fish in a polluted river absorbs 2 units of a toxin. If a larger fish eats 10 of these small fish, how many units of toxin does the larger fish accumulate?
Medium
- A2 units
- B10 units
- C20 units
- D12 units
5.A top predator in a food chain eats 15 animals, each with 10 units of toxin. How many units of the toxin does the predator accumulate from eating these animals?
Medium
- A10 units
- B15 units
- C150 units
- D25 units
6.Why is it advised that adults eat no more than 2 tuna steaks per week?
Easy
- ATuna is low in protein
- BTuna may contain high levels of mercury due to bioaccumulation
- CTuna is difficult to digest
- DTuna is an endangered species
7.Why was the pesticide DDT banned in many countries?
Easy
- AIt was ineffective against insects
- BIt caused birds to lay eggs with thin shells that broke easily
- CIt increased crop yields too much
- DIt was too expensive to produce
8.Which of the following best explains why top predators are most affected by bioaccumulation?
Medium
- AThey eat only plants
- BThey are at the highest trophic level and accumulate toxins from all lower levels
- CThey have larger bodies that produce more toxins
- DThey are exposed to toxins directly from the environment

Thêm câu hỏi

9.A lake is contaminated with a toxin that does not break down easily. Which organism would likely have the highest concentration of the toxin?
Medium
- APlankton
- BSmall fish that eat plankton
- CLarge fish that eat small fish
- DAquatic plants
10.Which human activity contributes to bioaccumulation of mercury in aquatic ecosystems?
Easy
- APlanting trees
- BBurning coal
- CUsing solar panels
- DRecycling paper
11.Which of the following is a way to reduce bioaccumulation?
Easy
- AIncreasing the use of pesticides
- BReleasing more industrial waste into rivers
- CUsing less toxic alternatives to pesticides
- DBurning more fossil fuels
12.In a food chain: plankton → small fish → large fish → bird. If the plankton contains 0.01 ppm of a toxin, and each step concentrates the toxin 10 times, what is the concentration in the bird?
Medium
- A0.1 ppm
- B1 ppm
- C10 ppm
- D100 ppm
13.In an aquatic food chain, plankton contain 0.02 ppm of a toxin. If each trophic level concentrates the toxin by a factor of 10, what is the concentration in a large fish that eats small fish that have eaten plankton? Assume the chain: plankton → small fish → large fish.
Medium
- A2 ppm
- B0.2 ppm
- C20 ppm
- D0.02 ppm
14.A lake is contaminated with a non-biodegradable pesticide. Which graph best shows how the concentration of the pesticide changes with trophic level?
Medium
- AIncreasing steadily
- BDecreasing steadily
- CRemaining constant
- DFluctuating randomly
15.In a food web, the concentration of a heavy metal in the tissues of different organisms is measured. The results are shown in the table. Which organism is most likely the top predator?
Medium
- AOrganism D: 15 ppm
- BOrganism C: 5 ppm
- COrganism B: 1 ppm
- DOrganism A: 0.1 ppm
16.Which of the following is a reason why DDT caused a decline in bird populations?
Easy
- AIt caused birds to lay eggs with thin shells that broke easily.
- BIt killed the insects that birds eat.
- CIt made birds more vulnerable to predators.
- DIt caused birds to migrate earlier.
17.A study measured mercury levels in fish from a river. The data shows: plankton: 0.01 ppm; small fish: 0.1 ppm; larger fish: 1.0 ppm; top predator fish: 10 ppm. What is the approximate biomagnification factor per trophic level?
Medium
- A10
- B100
- C0.1
- D1
18.Which of the following is NOT an example of a toxic substance that can bioaccumulate?
Easy
- AOxygen
- BMercury
- CDDT
- DLead
19.A farmer uses a pesticide that does not break down easily. Which of the following would be most affected by bioaccumulation of this pesticide?
Medium
- ABirds of prey that eat mice that ate the crops
- BEarthworms in the soil
- CCrop plants themselves
- DInsects that are targeted by the pesticide
20.In an experiment, 1000 kg of a lake's plankton contains 1 g of a toxin. If a small fish eats 10 kg of plankton, how much toxin does the fish accumulate?
Medium
- A0.01 g
- B0.1 g
- C1 g
- D10 g
21.Which human activity directly contributes to bioaccumulation of mercury in aquatic ecosystems?
Easy
- ABurning coal in power stations
- BPlanting trees along riverbanks
- CUsing solar panels
- DRecycling paper
22.A food chain consists of: algae → water flea → small fish → pike. The algae contain 0.005 ppm of a toxin. If each level concentrates the toxin 10 times, what is the concentration in the pike?
Medium
- A5 ppm
- B0.5 ppm
- C50 ppm
- D0.05 ppm
23.Why is it advised that adults eat no more than two tuna steaks per week?
Easy
- ATuna may contain high levels of mercury due to bioaccumulation
- BTuna is high in fat and calories
- CTuna is an endangered species
- DTuna farming uses antibiotics
24.In an experiment to study bioaccumulation, a researcher measures the concentration of a toxin in organisms from a lake. She finds that water fleas contain 0.02 ppm, small fish contain 0.2 ppm, and large fish contain 2.0 ppm. What is the most likely reason for this pattern?
Medium
- AThe toxin breaks down faster in larger fish
- BThe toxin is excreted by small fish more efficiently
- CThe toxin accumulates and magnifies as it moves up the food chain
- DThe toxin is absorbed directly from the water by large fish only
25.A student wants to test whether a pesticide bioaccumulates in a simple food chain: grass → grasshopper → frog. Which experimental setup would best demonstrate bioaccumulation?
Hard
- AFeed the pesticide directly to the frog and measure its concentration
- BSpray the pesticide on the grass, then measure concentrations in grass, grasshoppers, and frogs over time
- CMix the pesticide into the soil and measure its concentration in the air
- DInject the pesticide into the grasshoppers and measure frog behavior
26.In a study, scientists added a known amount of a non-biodegradable chemical to a pond. After one month, they measured the concentration in the water, in algae, in small fish, and in large fish. Which set of results would most clearly indicate bioaccumulation?
Medium
- AWater: 0.1 ppm, Algae: 0.2 ppm, Small fish: 0.4 ppm, Large fish: 0.8 ppm
- BWater: 0.1 ppm, Algae: 0.1 ppm, Small fish: 0.1 ppm, Large fish: 0.1 ppm
- CWater: 0.1 ppm, Algae: 0.01 ppm, Small fish: 0.001 ppm, Large fish: 0.0001 ppm
- DWater: 0.1 ppm, Algae: 0.5 ppm, Small fish: 0.3 ppm, Large fish: 0.2 ppm
27.A scientist wants to determine if a new pesticide is likely to bioaccumulate. Which property of the pesticide would be most important to investigate?
Medium
- AHow quickly it kills insects
- BHow easily it dissolves in water
- CHow long it takes to break down in the environment
- DWhat color it is
28.In a laboratory experiment, a food chain is set up: algae → daphnia (water flea) → small fish. A non-biodegradable toxin is added to the water at a concentration of 1.0 ppb. After two weeks, the concentration in the algae is 10 ppb, in daphnia is 100 ppb, and in fish is 1000 ppb. What is the biomagnification factor from daphnia to fish?
Medium
- A10
- B100
- C1000
- D0.1
29.A researcher collects samples from a marine food chain: phytoplankton → zooplankton → small fish → large fish → tuna. She measures mercury concentration (ppm) in each. Which sampling method would be most appropriate to ensure reliable data?
Medium
- ATake one sample from each organism at the same time and location
- BTake multiple samples from different individuals of each species over several months and average the results
- CTake samples only from the largest tuna because they are top predators
- DTake samples from the water only and estimate the concentrations in organisms
30.Which of the following is a valid method to reduce bioaccumulation of mercury in aquatic ecosystems?
Medium
- AAdding more mercury to the water to dilute it
- BUsing less toxic alternatives to pesticides and reducing industrial emissions
- CFeeding fish more food to flush out the mercury
- DHeating the water to break down mercury
31.Why did DDT cause a decline in bird populations?
Easy
- AIt poisoned the birds directly
- BIt caused birds to lay eggs with thin shells that broke easily
- CIt reduced the number of insects available for birds to eat
- DIt made birds migrate to different areas
32.A food chain consists of: algae → insect larvae → small fish → large fish → bird. The algae contain 0.005 ppm of a toxin. If the concentration multiplies by 10 at each trophic level, what is the concentration in the bird?
Medium
- A0.5 ppm
- B5 ppm
- C50 ppm
- D500 ppm
33.Which of the following is a reason why top predators are most affected by bioaccumulation?
Medium
- AThey eat a large number of organisms, accumulating toxins from each
- BThey are larger and can tolerate more toxins
- CThey excrete toxins more slowly
- DThey are exposed to toxins directly from the environment
34.In a lake contaminated with mercury, plankton contain 0.02 ppm of mercury. If each trophic level concentrates the toxin by a factor of 10, what is the concentration in a top predator fish that is three trophic levels above the plankton?
Medium
- A0.2 ppm
- B2 ppm
- C20 ppm
- D200 ppm
35.A researcher measures the concentration of a non-biodegradable pesticide in a food chain: algae (0.001 ppm), water fleas (0.01 ppm), small fish (0.1 ppm), large fish (1.0 ppm). What is the concentration factor per trophic level?
Medium
- A10
- B100
- C0.1
- D1
36.Which of the following graphs best represents the concentration of a bioaccumulating toxin as it moves up a food chain?
Easy
- AA bar chart with decreasing heights from producers to top predators
- BA bar chart with increasing heights from producers to top predators
- CA line graph showing a constant concentration across trophic levels
- DA pie chart showing equal distribution among trophic levels
37.In a study of a marine food web, mercury levels (ppm) were measured: phytoplankton 0.005, zooplankton 0.05, small fish 0.5, large fish 5.0, shark 50.0. Which statement best explains this pattern?
Medium
- AMercury is broken down by each organism
- BMercury is excreted efficiently by top predators
- CMercury accumulates and is passed along the food chain
- DMercury is produced by larger fish
38.A lake contains 1000 kg of plankton with a total of 1 g of a toxin. If a small fish eats 10 kg of plankton, how much toxin does the fish absorb?
Medium
- A0.01 g
- B0.1 g
- C0.001 g
- D1 g
39.Which of the following is an example of a heavy metal that can bioaccumulate?
Easy
- AOxygen
- BMercury
- CCarbon dioxide
- DNitrogen
40.In an experiment, a food chain is set up: algae → daphnia → small fish. A non-biodegradable toxin is added to the water at 0.1 ppm. After one week, the concentration in algae is 0.5 ppm, in daphnia is 5 ppm, and in small fish is 50 ppm. What does this demonstrate?
Medium
- AThe toxin is broken down by algae
- BThe toxin is excreted by fish
- CBioaccumulation is occurring
- DThe toxin is diluted in the water
41.Bioaccumulation only occurs in aquatic ecosystems.
Easy
True or false?
42.Which of the following is a heavy metal that can bioaccumulate?
Easy
- AMercury
- BOxygen
- CCarbon
- DNitrogen
43.DDT caused birds to lay eggs with thin shells.
Easy
True or false?
44.Match each toxic substance to its source or effect.
Medium
- Mercury
- DDT
- Released from coal burning
- Caused thin eggshells in birds
45.Arrange the following steps in the bioaccumulation of mercury in an aquatic food chain in the correct order, starting with the first step.
Medium
- Mercury is absorbed by plankton
- Small fish eat plankton and accumulate mercury
- Large fish eat small fish and concentrate mercury
- Mercury is released from industrial processes
- Top predators eat large fish and have highest mercury levels
46.Which of the following are ways to reduce bioaccumulation? (Select all that apply)
Medium
- AUse less toxic alternatives to pesticides
- BIncrease industrial waste dumping
- CEnforce stricter regulations on industrial waste
- DProperly dispose of toxic materials
- EBurn more coal
47.In a food chain, which trophic level is most likely to have the highest concentration of a bioaccumulating toxin?
Easy
- AProducers
- BPrimary consumers
- CSecondary consumers
- DTertiary consumers
48.Match each toxic substance to its typical source or effect.
Medium
- Mercury
- DDT
- Lead
- Causes thin eggshells in birds
- Released from coal burning
- Can cause neurological disorders
49.Arrange the following steps in the bioaccumulation of DDT in an aquatic food chain, starting with the first step.
Medium
- DDT is sprayed on crops and runs into water
- Small organisms absorb DDT
- Small fish eat the organisms and accumulate DDT
- Birds of prey eat the fish and have high DDT levels
- DDT causes thin eggshells in birds
50.Which of the following are toxic substances that can bioaccumulate? (Select all that apply)
Medium
- AMercury
- BOxygen
- CDDT
- DLead
- ECarbon dioxide
51.State two examples of toxic substances that can lead to bioaccumulation.
Easy
52.Complete the sentence.
Easy
Bioaccumulation is the process by which ____ substances build up in the tissues of organisms over time.
53.Describe why the pesticide DDT has been banned in many countries.
Medium
54.Define bioaccumulation and describe how it occurs in an ecosystem.
Medium
55.Describe how human activities contribute to bioaccumulation and suggest ways to reduce its impact on ecosystems.
Hard

Ghi chú ôn tập

## Bioaccumulation **Bioaccumulation** is the process by which toxic substances build up in the tissues of organisms over time. These toxins include chemicals like pesticides, heavy metals (e.g., mercury, lead), and other pollutants that enter the environment via air, water, or soil. Once in an ecosystem, toxins move through the food chain and become more concentrated in animals higher up the chain. ### Examples - **Mercury**: Released from industrial processes (e.g., coal burning). In aquatic ecosystems, plankton absorb mercury; small fish eat plankton and accumulate mercury; larger fish (e.g., tuna) eat smaller fish, concentrating mercury further. Top predators (including humans) can suffer health risks like neurological disorders. - **DDT**: A pesticide that accumulated in the environment, especially in water. It became concentrated in birds of prey (e.g., eagles), causing thin eggshells that broke before hatching, leading to population declines. DDT is now banned in many countries. ### Prevention - Reduce release of harmful chemicals. - Use less toxic alternatives to pesticides. - Enforce stricter regulations on industrial waste. - Proper disposal of toxic materials. ### Key Points - Toxins become more concentrated at each trophic level. - Bioaccumulation can cause serious health and environmental problems. - Human activities (e.g., industry, agriculture) contribute to bioaccumulation.

Bioaccumulation: The process by which toxic substances build up in the tissues of organisms over time.
Toxin: A poisonous substance that can cause harm to organisms.
Food chain: A sequence of organisms where each is eaten by the next, showing the flow of energy and materials.
Mercury: A heavy metal that can bioaccumulate, released from industrial processes like coal burning.
DDT: A pesticide that bioaccumulates, causing thin eggshells in birds of prey; now banned in many countries.
Top predator: An animal at the top of a food chain, with no natural predators, which often has the highest concentration of toxins.

Thẻ ghi nhớ

What is bioaccumulation?

Bioaccumulation is the process by which toxic substances build up in the tissues of organisms over time.

Name three types of toxic substances that can bioaccumulate.

Pesticides, heavy metals (e.g., mercury, lead), and other pollutants.

How do toxins enter the environment?

Through air, water, or soil.

What happens to toxin concentration as you move up a food chain?

Toxins become more concentrated in the bodies of animals higher up the food chain.

Give an example of a heavy metal that bioaccumulates and its source.

Mercury, released from industrial processes like coal burning.

Describe the bioaccumulation of mercury in an aquatic food chain.

Mercury is absorbed by plankton, then small fish eat plankton and accumulate mercury, larger fish eat small fish and accumulate more mercury, and top predators (including humans) get dangerously high levels.

What health risks are associated with high mercury levels in humans?

Neurological disorders.

Why is there NHS advice to eat no more than 2 tuna steaks per week?

Because tuna are large predatory fish that can have high mercury levels due to bioaccumulation, which can be harmful to health.

What is DDT and why was it used?

DDT is a pesticide used extensively in agriculture to control insects.

How did DDT affect birds of prey like eagles and ospreys?

DDT caused them to lay eggs with very thin shells that often broke before hatching, leading to population decline.

Why was DDT banned in many countries?

Because it accumulated in the environment and caused severe harm to wildlife, especially birds of prey.

What are two ways to prevent bioaccumulation?

Reducing release of harmful chemicals and using less toxic alternatives to pesticides.

How can stricter regulations help reduce bioaccumulation?

By enforcing stricter regulations on industrial waste and ensuring proper disposal of toxic materials.

A small fish has 2 units of toxin. If a larger fish eats 10 such small fish, how many units does the larger fish have?

20 units (assuming all toxin is retained).

A top predator eats 15 animals each with 10 units of toxin. How many units does the predator accumulate?

150 units.

Name two human activities that contribute to bioaccumulation.

Industrial processes (e.g., coal burning) and use of pesticides in agriculture.

What is an example of a pollutant that bioaccumulates in aquatic ecosystems?

Mercury or DDT.

How does bioaccumulation occur in an ecosystem?

Toxins enter the environment and are absorbed by small organisms; as larger organisms eat smaller ones, the toxins accumulate and become more concentrated in higher trophic levels.

What is the difference between bioaccumulation and biomagnification?

Bioaccumulation is the buildup of toxins in an individual organism over time; biomagnification is the increase in concentration as toxins move up the food chain. (Note: Source uses bioaccumulation broadly.)

Why are top predators most affected by bioaccumulation?

Because they consume many prey animals, each with accumulated toxins, leading to the highest concentrations in their bodies.

What effect did DDT have on bird eggshells?

It caused eggshells to become very thin and fragile, often breaking before chicks could hatch.

How can using less toxic alternatives to pesticides help?

It reduces the amount of harmful chemicals entering ecosystems, thus decreasing bioaccumulation.

What is a heavy metal that can bioaccumulate and cause health issues?

Mercury or lead.

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