Risks and Benefits of Chemicals: - wsfcs.k12.nc.us
Risks and Benefits of Chemicals:
Chemicals are essential to life on Earth. Humans have developed chemicals to use for sanitation, preserving foods, treating diseases, and increasing crop yields (amount). Although many chemicals are beneficial, others are harmful to humans and other organisms.
Risks and Benefits
• The development and use of chemicals offer both benefits and risks to people, organisms, and the environment.
• Benefits are how the chemical meets the needs of society.
• Risks describe how the chemical might negatively affect the environment or create unsafe conditions for people.
• The process of weighing the potential harm of using a new technology against its benefits is called risk-benefit analysis.
Sanitation
• Sanitation involves all of the methods used for the removal, treatment, and disposal of wastes.
• Wastewater treatment is an example of sanitation.
• Charcoal, a form of carbon, is used to filter contaminants from water.
• Chlorine is used to kill bacteria and other microorganisms.
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Food Preservatives
• Chemicals used to prevent food spoilage caused by microorganisms are food preservatives.
• Salt and vinegar were the first food preservatives and inhibit the growth of microorganisms.
• Some chemicals are added to foods to slow oxidation.
• Oxidation is a chemical reaction that occurs when a substance reacts with oxygen.
• Oxidation can cause foods, such as fruits, to turn brown or black.
• Food preservatives can keep food safe for use for longer periods of time than food not treated with preservatives.
• Some people have an allergy for food preservatives, which is an immune response to proteins in certain foods.
• A food intolerance is an inability to digest a food or a food additives.
• To lower the risk of such problems, companies must list all ingredients on the label.
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Medicines
• In the late 1800’s, a German chemist isolated and identified the chemical commonly known as aspirin.
• Today, aspirin is just one of thousands of chemicals that are used as medicines to treat diseases from the common cold to cancer.
Antibiotics
- Antibiotics are a group of medicines used to kill bacteria that cause disease.
- Penicillin was the first antibiotic.
- Before antibiotics, a person could die from an infection caused by a scratch.
- Today, many different kinds of antibiotics are used to treat a wide variety of diseases caused by bacteria.
Chemicals & Crop Yields
• Two groups of chemicals are used to increase crop yields: fertilizers and pesticides
• Fertilizers are chemicals that promote plant growth and benefit plants.
• However run-off carrying fertilizers into streams and ponds can cause an excessive growth of algae that actually harms ecosystems.
• Pesticides are chemicals designed to kill organisms that are considered pests.
• Today, about 10 billion kilograms of pesticides are used each year worldwide.
• The benefit of pesticides is an increase in crop production.
• However, some pesticides such as DDT, can have harmful effects on the organisms they were not intended to kill.
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Review Questions:and COACH page 228,1-4
1. What is the benefit of adding chlorine to water before it is usable?
- To kill bacteria and other microorganisms.
2. How do food preservatives work?
- Added chemicals make food last longer.
3. Why must all ingredients be listed on food labels?
- Because people may have a food allergy or intolerance to an ingredient.
4. What do antibiotics do?
- Antibiotics kill bacteria that cause disease.
5. Explain the difference between fertilizers and pesticides.
- Fertilizers promote plant growth and pesticides kill organisms.
COACH page 228:
1. C
2. D
3. B
4. C
Ticket out the door:
Identify the risks and benefits of at least two chemicals you use daily.
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