Unit C: Environmental Chemistry (Social and Environmental Contexts emphasis)
Overview:
Environments are often viewed from a physical and biological perspective, but to fully understand how they function,
it is important to view them from a chemical perspective as well. A study of environmental chemistry helps students
become aware that chemical substances make up the underlying fabric of the world and are part of the process in
all natural cycles and changes. Through this unit students also become aware of human-produced chemical substances
that enter and interact with environments, and investigate potential impacts of different substances on the distribution
and abundance of living things.
This unit builds on ideas introduced in Science 8 Unit A: Cells and Systems, Unit B: Mix and Flow of Matter, Unit
E: Fresh and Saltwater Systems, and Science 9 Unit B: Matter and Chemical Change. The unit introduces ideas that
will be developed further in Science 10 Unit C: Flow ofMatter in Living Systems and in Science 20 Unit B: Changes
in Living Systems.
Focussing Questions: What substances do we find in local and global environments?
What role do they play?
How do changes in their concentration and distribution affect living things?
Key Concepts
Students will: Investigate and describe, in general terms, the role of different substances
in the environment in supporting or harming humans and other living things
Identify common organic and inorganic substances
that are essential to the health and growth of humans and other living things and illustrate the roles served by
these materials (e.g., identify calcium as an essential materialfor bones; identify minerals that are known to
enhance plant growth-but that limit growth if too little or too much is available).
Describe, in
general terms, the forms of organic matter synthesized by plants and animals.
Describe and
illustrate processes by which chemicals are introduced to the enviromnent or their concentration is changed (e.g.
dilution in streams, biomagnification throughfood chains)
Describe the
uptake of materials by living things through ingestion or absorption.
Investigate
and describe evidence that some materials are difficult for organisms to break down or eliminate (e.g., DDT mercury)
Identify questions
that may need to be addressed in deciding what substances, in what amounts, can be safely released into the environment
(e.g., identify questions and considerations that may be important in determining how much phosphate should be
released into river water).
Students will: Identify processes for measuring the quantity of different substances in the
environment, and for monitoring air and water quality
Identify substrates and nutrient sources for
living things within a variety of environments.
Describe and
illustrate the use of biological monitoring as one method for determining enviromnental quality (e.g. assess water
quality, by observing the relative abundance of various vertebrate and invertebrate species)
Identify chemical
factors in an environment that might affect the health and distribution of living things in that environment (e.g.
available oxygen, pH, dissolved nutrients in soil).
Apply and interpret
measures of chemical concentration in parts per million, billion or trillion. [Prerequisite Skills: Grade 8 Matbematics,
Number Operations, SO 14, 15] Identify acids, bases and neutral substances
based on measures of their pH (e.g., use indicator solutions or pH meters to measure the pH of water samples)
Investigate
safely and describe the effects of acids and bases on each other and on other substances (e.g., investigate and
describe the reaction that results when baking powder is dissolved)
Describe the
role of acids and bases in neutralizing each other.
Describe effects
of acids and bases on living things (e.g., acid rain in lakes, antacids for upset stomachs; pH in shampoos and
conditioners)
Students will: Analyze and evaluate mechanisms affecting the distribution of potentially
harmful substances within an environment
Describe mechanisms for transfer of materials
through air and water.
Identify factors
that may accelerate or retard their distribution (e.g., wind speed, soil porosity).
Describe mechanisms
for biodegradation, and interpret information on the biodegradability of different materials.
Comprehend
and interpret information on the biological impacts of hazardous chemicals on local and global environments (e.g.,
interpret evidencefor environmental changes in the vicinity of a substance release, interpret LD50 data) [LD50 refers to the amount of a substance found to be lethal to 50% of a population,
if ingested] Identify concerns with disposal of domestic
wastes such as paints and oils, and industrial wastes.
Describe and
evaluate methods used to transport, store and dispose of hazardous household chemicals. (e.g. Swan Hills, Alberta)
Investigate
and evaluate potential risks resulting from consumer practices and industrial processes.
Identify processes
used in providing information and setting standards to manage these risks (e.g., interpret and explain the significance
of manufacturer's information on how wood preservatives can be safely applied, recognize that individuals may have
greater sensitivity to particular chemical substances than do others in the general population).
Identify and
evaluate information and evidence related to an issue in which environmental chemistry plays a major role (e.g.
evaluate evidence that the use of insecticides to control mosquitoes has an effect/has no effect on bird populations)