1. Environmental Chemistry
Chapter Two

2. Review Why are we so concerned about environmental quality?
Where do pollutants fit into this?

3. Monitoring Water Quality
Section 2.1

4. Would you swim here?

5. Water Quality
Monitoring water quality is an ongoing process carried out by governments and industry
Water quality is measured based on clarity, biological and chemical indicators

6. Water Quality
There are 5 category guidelines for water quality, based on their use:
Human drinking water
Recreation such as swimming
Livestock drinking water
Irrigation
Protection of aquatic life
These guidelines are designed to protect all organisms living in or near water ecosystems
They are measured using both biological and chemical indicators

7. Biological Indicators
Biological indicators include fish, plants, worms, insects, plankton, protozoa, bacteria and viruses
Microbial Indicators
These include the number and type of microscopic organisms
E. coli is the main indicator used for drinking water

8. Aquatic Invertebrates
These indicators may not be harmful in themselves, but can show the effects of pollution
Invertebrates are organisms without a backbone
These are used for monitoring because each organism has its own niche and preferred water conditions

9. Aquatic Invertebrates and other Biological Indicators
Why might we not get as good of an idea about water quality when using biological indicators?
What other ways do we have to measure water quality?

10. Measuring Chemicals in the Environment
The concentration of chemicals in the environment (water, air, etc.) is usually done in parts per million or mg/L
parts per million (ppm) – a unit of concentration describing how many particles of compound are present for every million parts of solution
Demo
Food colouring
Dilute solution of food colouring while reading over as a class

11. Practicing ppm, ppb, and ppt
How do we calculate ppm?
Work through the ex. on pg. 216 as a class
Skills Practice – Pg. 217
With a partner work through the skills practice
We will go over them as a class in about 5 min

12. Measuring Chemicals in the Environment
Why might it be worth it for us to measure concentrations in ppb or ppt?
Some substances, once in the food chain, can increase in concentration in animal tissues as they move higher in the food chain (we will discuss this in section 3.3)

13. Chemical Factors that Affect Organisms
The following factors affect all organisms in aquatic ecosystems
Dissolved oxygen
Acidity
Heavy metals
Plant nutrients
Pesticides
Salts

14. Dissolved Oxygen
Oxygen is dissolved into water, and this oxygen is essential to the health of aquatic organisms such as fish, insects, and micro-organisms
The level of dissolved oxygen depends on the following factors:
Temperature (abiotic)
Turbulence (abiotic)
Amount of photosynthesis (abiotic)
Number of organisms using oxygen (biotic)

15. Dissolved Oxygen
Most organisms need 5 milligrams per Litre (5 ppm) of dissolved oxygen to survive
The diversity of species often gives us a relative idea of the amount of dissolved oxygen present
A large number of different species means a high level (likely 8 ppm or more) of dissolved oxygen, whereas a few species indicates a low level (below 5 ppm) of dissolved oxygen

16. Dissolved Oxygen (ppm or mg/L)
Invertebrates 8
Large numbers of diverse invertebrates 6
Mayflies, stoneflies, and beetles begin to disappear 4
Freshwater shrimp, midge larvae, and worms can survive 2
Midge larvae and some worms can survive

17. Phosphorous and Nitrogen Content
Phosphates and Nitrates often enter the water supply by sewage and runoff
They increase the growth of algae and weeds in the water
This then increases the food supply for bacteria, which decompose the plants, as they die
The presence of more and more bacteria uses up the available supply of dissolved oxygen and many of the aquatic organisms die as a result

18. Phosphorous and Nitrogen Content

19. pH Testing, Acid Rain and Acid Shock
Sulfur and nitrogen oxides emitted from industries (such as smelters) combine with water vapor in the air to produce sulfuric and nitric acid.
These pollutants then fall to the ground as acid rain (with a pH lower than normal rain - which is about 5.6)

20. Acid Rain
... causes chemical changes in the soil reduces soil fertility
... retards tree growth
... kills organisms in lakes & streams
... corrodes exposed metal surfaces
... breaks down stone and limestone
... leaches toxic chemicals from the soil

21. pH Testing, Acid Rain & Acid Shock

22. Acidity
Acidity is measured on the pH scale with 7.0 being neutral and anything below 7 is acidic
A decrease of one unit indicates the acidity has been multiplied by a factor of 10
Periods of extreme acidity (like in the spring when the acid snow melts and the acidic water enters the waterways) are called acid shock

23. Pesticides
Some insects have become pesticide-resistant and so, new pesticides have to be developed
When these chemicals remain in the environment, a toxin is created
Several pesticides mixed together can have a cumulative effect and become very toxic
A toxic substance is poisonous

24. Pesticides
Today, pesticides are designed to only last one growing season, to reduce their toxic effects and build-up
They are broken down by bacteria so they are no longer toxic

25. Biomagnification
Biomagnification is the increase in concentration of a chemical or element as it moves up the food chain
Demo

26. Measuring Toxicity
Toxins, or poisons are substances that produce serious health problems, or death when introduced into an organism
Scientist measure toxins in LD50 amounts
LD stands for Lethal Dose; and 50 represents 50% of the subject group that will die if they are given the specified dose, all at once

27. LD50 Testing LD50 testing is usually done on rats and mice
Substance
LD50
Subject/How delivered
Table Salt
3000 mg/kg
Rat, by mouth
Caffeine
192 mg/kg
DDT (pesticide)
87 mg/kg
LD50 testing is usually done on rats and mice
It is stated as the amount of chemical given per unit of body mass

28. Heavy Metals Heavy metals have a density of 5g/cm3 or more
Examples include: mercury, copper, lead, zinc, cadmium and nickel
These metals occur naturally and are also processed into a wide variety of products
Heavy metals can be toxic to a wide range of organisms, so concentrations are constantly monitored

29. Heavy Metals
Heavy metals can enter the water supply by the action of acid rain and improper solid waste disposal (which can leach heavy metals into the groundwater)
Heavy metals are especially toxic to children cause abnormal development, brain damage or even death

30. Assignment
Check and Reflect Pg. 224
#1-12

31. Check and Reflect Pg. 224 Categories of water use are:
Human drinking water
Recreation
Livestock drinking water
Irrigation
Protection of aquatic life
Four groups organisms that can be found in freshwater ecosystems are: insects, crustaceans, worms, and mollusks
Five chemicals regularly monitored are: dissolved oxygen, acids, heavy metals, plant nutrients, pesticides
Spring acid shock reduces the numbers and diversity of aquatic organisms because it harms their eggs as well as young offspring.
Mayflies and stoneflies do not tolerate acidic conditions.

32. Check and Reflect Pg. 224 30 ppm 1500 ppm
Concentrations are: 2000 ppm, 9 ppm, 62 ppm.
Water from sample B will support the greatest diversity of organisms because sample A has too low a dissolved oxygen count, a slightly acidic pH, and a high level of phosphates that will encourage plant and algal growth.
According to this statement, salt will kill half of a population of test animals at dosages of 3000 mg per kilogram of body mass. This dosage was determined from studies done with rats.
Excess phosphorous supports growth of algae and other plants. When these plants die, they are food for bacteria. The bacteria thrive because food is available, and they use up the oxygen in the water for cellular respiration. When the dissolved oxygen count in the water goes down, fish, amphibians, and many insects cannot survive.
Monitor more locations to determine the source, remove contamination, to alert and educate the people affected by the contamination, and to impose stricter guidelines.

33. Check and Reflect Pg. 252
Answers will vary. Mercury is the example used in the text. Mercury is attached to an organic molecule in water to become organic mercury. This is taken up by algae. Insects may eat many algae. The fish that east insects containing mercury takes in a large quantity of mercury and stores it in its tissue. People who eat the fish containing the mercury may take in enough to harm various organs

34. Monitoring Air Quality
Section 2.2

35. Monitoring Air Quality
Take a deep breath…

36. Monitoring Air Quality
Air quality can be determined in two ways
By measuring the levels of pollutants in the air
2. By estimating the amount of emissions from pollution sources

37. Sulfur Dioxide (SO2(g))
Sulfur dioxide (SO2(g)) is a major air pollutant that forms both smog and acid rain
It can affect your respiratory system and irritate your eyes
The major source of SO2(g) is from industrial processes
Ex. Alberta’s oil and industry

38. Sulfur Dioxide (SO2(g))
In industries, scrubbers are used to reduce sulfur dioxide emissions up to 99%
They use limestone to convert it to a useful product

39. Nitrogen Oxides (NOx(g))
Nitrogen oxides (NOx(g)) are also major air pollutants that form both smog and acid rain
They affect the respiratory system and eyes
The major source of nitrogen oxides is from the combustion in cars as well as generating plants and industrial processes

40. Nitrogen Oxides (NOx(g))
Both sulfur dioxide and nitrogen oxides are carefully monitored, especially in cities and areas where industrial processes may release these pollutants

41. Carbon Monoxide CO(g)
Often referred to as the silent killer because it is colourless and odourless gas
Carbon monoxide is formed when chemicals contained carbon burn and there is not enough oxygen to form carbon dioxide (CO2(g))
The main source of carbon monoxide from human activities is from motor vehicles
Carbon monoxide is also produced from forest fires, natural gas, industrial processes, airplanes, and cigarettes

42. Carbon Monoxide CO(g) Health effects:
If inhaled, carbon monoxide reduces the amount of oxygen in the blood and can cause
Headaches
Sleepiness
Chest pains
Brain damage
Death
Catalytic converters are used to convert carbon monoxide into carbon dioxide

43. Ground-Level Ozone What is Ozone?
Ozone ( O3(g) ) is an odorless, colorless gas that has 3 oxygen atoms.
It protects us from harmful ultraviolet rays from space, but at ground-level it can be harmful, because it can affect the respiratory system, deteriorate plastics and can have serious effects on crops.

44. Ground-Level Ozone
Ground-level ozone forms from reactions between oxygen, nitrogen oxides and compounds that are volatile organic compounds (VOC’s), in the presence of sunlight and heat.
Fuel combustion is the major source.

45. Ground-Level Ozone

46. Assignment Work on Check and reflect questions Page 228

47. Check and Reflect
2) a) Scrubbers are designed to remove sulfur dioxide from emissions b) The products are gypsum and carbon dioxide 3) CO(g) is a poison that reduces the amount of oxygen that can be carried by the blood. (CO attaches to the red blood cells in place of oxygen) 5) Ozone in the upper atmosphere helps shield Earth from harmful UV rays. Ozone near the surface of Earth is a component of smog and when combined with other chemicals it can aggravate allergies, bronchitis, and asthma. 8) a) Harmful compounds from car exhausts include nitrogen oxides, carbon dioxide, and carbon monoxide. b) Catalytic converters convert carbon monoxide into carbon dioxide, hydrocarbons into carbon dioxide and water, and nitrogen oxide into nitrogen and oxygen c) Some people argue that catalytic converters increase the amount of CO2(g), a greenhouse gas, in the atmosphere

48. Monitoring the Atmosphere
Section 2.3

49. Monitoring The Atmosphere
Section Review:
What type of chemicals are harmful to the environment?
What is a pollutant?

50. Monitoring the Atmosphere
Chemicals in our atmosphere can cause mild to serious health effects in local areas
Some chemicals can have serious global effects
Examples: Ozone depletion and climate change are the primary concerns

51. Carbon Dioxide as a Greenhouse Gas
Carbon dioxide occurs naturally in our environment so it is not considered a pollutant
However, increasing amounts that are being produced by various human activities is creating a concern
The increasing population and increasing use of fossil fuels is creating issues

52. The Greenhouse Effect What is it?
The greenhouse effect is a naturally occurring event, the result of greenhouse gases trapping some of the outgoing energy
This retains heat in a way somewhat similar to the glass panels of a greenhouse

53. The Enhanced Greenhouse Effect
Human activities such as burning fossil fuels and clearing land are contributing to the enhanced greenhouse effect
This effect results from the greater concentration of gases trapping even more heat
This in turn, increases the overall temperature of the Earth which we refer to as global warming

54. Global Warming
Global warming may lead to climate change which could then dramatically affect living things all over the world
These could include:
More violent storms
Flooding of coastal areas
Spread of diseases

55. Global Warming
Monitoring stations are set up to record the higher levels and governments are trying to find ways to reduce the emissions of carbon dioxide which is fueling this enhanced greenhouse effect and depleting the ozone layer.

56. Global Warming
Scientists have concluded that global warming is taking place and that it is caused partly by human activities
Natural activities such as volcanic eruptions and forest fires may also be part of the cause

57. Global Warming
Some countries have already started to reduce their carbon dioxide emissions
Examples
Windmill farms
Forest projects

58. The Ozone Layer What is the Ozone Layer
Atmospheric ozone is the chemical that occurs high the atmosphere where it maintains a shield around the Earth protecting everyone from harmful UV radiation

59. The Ozone Layer
The ozone layer is a natural formation 15 to 50 kilometers above us.
Since the late 1970’s, Scientists who have been monitoring this protective layer, have noticed that it is becoming thinner.
They have also discovered holes in the layer. This results in more UV radiation getting through to the surface of the Earth and increasing the likelihood of more organisms getting skin cancer and cataracts.
It is also affecting the plankton population, which is an important food supply for many animals.

60. The Role of Chlorofluorocarbons
The thinning of the atmosphere is caused by our use of chlorofluorocarbons ( CFC’s ).
air-conditioning, refrigeration, blowing agents in foams, insulations and packing materials, propellants in aerosol cans.
These chemicals eventually get into the upper atmosphere where they are broken down into elements like chlorine which destroys ozone.
1 chlorine atom can destroy 100,000 ozone molecules. Many countries have signed agreements to reduce their use of these chemicals.

61. Assignment Answer Check and Reflect Questions Page 233

62. Check and Reflect
Four greenhouse gases are: water vapour, carbon dioxide, methane, and nitrogen dioxide
3) a) Our use of CFC’s has contributed to the thinning of the ozone layer
b) A thinning ozone layer allows more ultraviolet (UV) radiation to reach Earth’s surface. UV radiation causes increases in skin cancer and cataracts; an kills plankton, an this, in turn, affects food chains
4) To protect the ozone layer, countries have agreed to reduce their CFC’s. Some are monitoring the amounts of CFC’s in the environment, and they have banned the use of CFC’s in some products

63. Check and Reflect
5) CO2(g) has up over the last century; more fuel is being burned, and forests are being cut down 6) The greenhouse effect is a natural occurrence. Gases in the atmosphere such as CO2(g) trap the heat that forms when energy from the Sun reaches Earth’s surface. The enhanced greenhouse effect refers to the result of human activity causing increasing amounts of greenhouse gases such as CO2(g) in the atmosphere. These increased levels cause even more heat to be trapped. 7) Atmospheric CO2(g) levels should be lowest in Alberta in the Summer months because there is more plant growth at that time