Unit C – How molecules move through Nature

Transport of Materials through Air, Soil and Water

I Can… State that wind, ocean currents, and rivers carries pollutants from one area to another

Questions When pollution is found far from where it was produced it brings up many questions 1) Where was the source? 2) Who is to blame for it spreading? 3) Who should pay for the spread of pollutants?

Transport in the Air There are 3 parts to the transport of substances in the air 1) Release of the chemical at the source 2) Dispersion of the chemical in the atmosphere 3) Deposition of the chemical in soil or water

Quick Lab Complete the Quick Lab Activity Sheet with your table partner

Factors that Affect Dispersion Wind Precipitation The pollutants properties This can make it impossible to find where the pollutant came from Makes this issue an international one What does that mean?

Transport in Groundwater Groundwater is a zone in the soil where all the spaces in the soil are filled with water The water table is the top level of the groundwater zone

Speed of Groundwater Movement Groundwater can move as quickly as 1 m per day or as slow as 1 m per year If the water is moving slowly then there can be a concentration of contaminants in that area

Types of Soils Soils can be made of many different things Packed clay- impermeable to water Sandy soil- easy for water to move through Soil with organic material- can slow the movement of water through it Pores are the tiny spaces between the soil Permeable soil has lots of spaces in it. Example: soil mainly made with sand Impermeable soil has little to no spaces in it. Example: soil mainly made with clay

Groundwater Zones – Label your Picture!

Substances that Contaminate Water

Transport in Surface Water Surface water can be contaminated from the air, groundwater, runoff from fields, and outflow from the storm sewers and sewage treatment plants. Contaminants in the surface water can be dangerous when it is a drinking water source Needs to be monitored

Transport in Soil When water comes down in precipitation it can do four things 1) Some evaporates 2) Some soaks into the soil and is taken in by plants 3) Some runs onto the street or into a stream 4) Some soaks through the soil and moves downwards

Leachate Leachate is water that has dissolved minerals in it and it carries the minerals with it- usually downwards

Transport of Hydrocarbons in Soil There are many sites in Canada where contamination of the soil by hydrocarbons is an issue. Where could this be a problem? Some contamination is difficult to clean up because it isn’t water soluble

Think about it! Lead from a car battery has been detected in a lake far where the battery was discarded. How did the lead get there? One water well is located in sandy soil, and another well is in soil that is mainly clay. Which well should be monitored more often? Why is this?

Acids and Bases We will talk about acids and bases in more detail in our chemistry unit We need to be familiar with pH for this unit

What is pH pH demo activity What do you observe? What are some patterns you notice? What do you find interesting?

The pH Scale pH stands for the Power of Hydrogen The pH scale measures how much hydrogen there is to react or how much a substance wants a hydrogen Acids are on the low end of the pH scale (0-6.9) and bases are on the high end (7.1-14) A substance with a pH of 7 is neutral Substances at both ends of the scale are dangerous. (Strong Acids and Strong Bases)

pH Numbers The difference between one number and the next on the pH scale is a 10x difference For example: a substance with a pH of 3 is 10x more acidic than a substance with a pH of 4 How much more acidic is a substance with a pH of 5 to one with a pH of 8?

Measuring pH We use 3 types of tests to check for the pH of a substance 1) Indicator- a liquid that changes colour dependent on the pH of a solution 2) Indicator paper- paper changes colour dependent on the pH 3) Litmus paper- changes colour (red or blue) dependent on if it is an acid or a base

Acid Rain When pollution is put into the environment the rain water can collect those substances and become very acidic This occurs more in Eastern Canada than Western Canada because there is more manufacturing in Eastern Canada https://www.youtube.com/watch?v=Nc6j7zz1_do

Consequences of Acid Rain It makes our rivers and lakes very acidic which can kill organisms It can cause destruction of limestone buildings and structures

Liming Liming is adding a base (lime) to a lake to try and return the lake to a health pH

Neutralization Neutralization occurs when an acid and a base react to form a salt and water Think of your Vinegar and Baking Soda Experiment! Acidification is the process where the pH of a body of water drops over a period of time due to meltwater

Think about it! You are at a pond which is near a factory. The pond’s pH is 5.3. Due to the pH, the fish in the pond are not repopulating. How can you change the pH so that the fish can reproduce? Note: pH 4.1 - 9.5 = Range tolerated by trout

Acidity Read page 220 as a class What is the issue with our water systems becoming more acidic? Spring acid shock is where the pH of a body of water drops over a period of time due to meltwater. What is the issue of this?

Acids Bases and pH Lab Complete lab

Pesticides Some pesticides do not break down and they can be harmful many years after they have been applied to a crop A toxic substance is a poisonous substance Toxicity measures how poisonous a substance is

LD50 Toxicity is measured using LD50 LD50 is lethal dose 50 It is a measurement of how much of a chemical needs to be applied before 50% of the population dies NOTE: the more toxic a substance is the LOWER the LD50 (takes less to kill off 50% of the population)

LD50 Examples Substance LD50 Subject/ How it was delivered Table Salt 3000 mg/kg Rat- by mouth Caffeine 192 mg/kg DDT (pesticide) 87 mg/kg

Heavy Metals Heavy metals are a category of metals that are 5x or more heavy than water Heavy metals damage living things Some examples: lead, mercury, copper, zinc and nickel Water can be used to test for these metals

Think about It! Explain the following statement: the LD50 is 3000mg/kg for rats.

Monitoring Air Quality https://www.youtube.com/watch?v=IjpKnoHOu8M Why is it important to monitor air quality?

2 Ways of Monitoring Air Quality 1) By measuring the levels of pollutants in the air 2) By estimating the amount of emissions from pollution sources Which way of monitoring air quality would be more accurate?

Make Up of our Atmosphere Nitrogen- 78% Oxygen- 21% Argon- less than 1% Carbon Dioxide- 0.03% Traces of hydrogen and neon

Sulfur Dioxide These chemicals are sources of air pollution They are formed by burning fuels such as fossil fuels Industrial and electrical generating plants use “scrubbers” to remove as much as 99% of the sulfur dioxide Sulfur dioxide can be used to make a useful product- calcium sulfate

Nitrogen Oxides Nitrogen oxides are created mainly from combustion in cars and from some manufacturing plants Nitrogen oxides are a large part of smog

Carbon Monoxide CO is created when there is not enough oxygen for combustion What is that called again? CO can be produced by car emissions, forest fires, and industrial processes A catalytic converter attached to vehicles converts CO into CO2

Ozone Ozone is a molecule made up of 3 oxygen atoms It provides a protective layer and blocks the earth from UV rays It can be damaging to the respiratory tract of people who have asthma, etc. Can be beneficial or harmful

Think About It! https://www.youtube.com/watch?v=tztGWe08NbA Does the air quality in China affect people in North America? Explain how by creating a suggestion for improving air quality https://www.youtube.com/watch?v=85nPyj6ANgs&t=44s

Monitoring the Atmosphere https://www.youtube.com/watch?v=3v-w8Cyfoq8 https://www.youtube.com/watch?v=0SYpUSjSgFg (Futurama) What is the greenhouse effect?

What does the Greenhouse Effect look like?

Greenhouse Gases Atmospheric gases that trap heat around the earth are called greenhouse gases Greenhouse gases include water vapour, carbon dioxide, methane and nitrogen oxides Are greenhouse gases necessary?

The Enhanced Greenhouse Effect and Global Warming People are concerned that the enhanced greenhouse effect can cause the temperature around the globe to rise If this happens- people worry that global warming can cause erratic weather patterns, polar ice caps melting, etc.

Global Warming/ Carbon Emissions/ Carbon Footprint/ Carbon Tax Some countries are reacting extremely to the concern of global warming- they are trying to cut down carbon emissions What have you heard about carbon footprint? Do you think it is fair to charge a carbon tax?

Ozone Layer and CFC’s Read page 232 as a class CFC’s (chloroflurocarbons) which are released from old air conditioners and fridges can cause a break down of ozone in the troposphere

Think about It! Look at the infographic in your notes. Should we be doing more to about CO2 Levels globally? Create a list of suggestions with your neighbor in class.