Topic 2.0: quality of chemicals im environment can be monitored Flashcards Preview

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Flashcards in Topic 2.0: quality of chemicals im environment can be monitored Deck (30):

Water quality is determined according to the 5 categories:

Human drinking water
Livestock drinking water
Protection of aquatic life


Lakes change due to...

They become cloudy in the summer because of excessive algae growth
It reduces the oxygen content in the lake, effects the types of organisms that live there
Ex. Trout is one of the first fish to die when the concentration of dissolved oxygen decreases


Not a good indicator of water quality:

Clarity is not a good indicator of water quality because clear water can sometimes be harmful to humans and other organisms
Ex: lakes affected by acid rain are crystal clear and lifeless


Biological indicators

Scientists use organisms that live in water to help determine water quality
These indicators can be:
Microbiological indicators
Aquatic invertebrates


Microbiological indicators

Organisms such as bacteria cause serious health problems if they are present in large numbers
Samples of water are taken and tested for microorganisms... If the count is high the water requires additional treatment before it is considered for for humans


Aquatic invertebrates

Invertebrates are animals without backbones are one group of indicator organisms
Crustaceans, worms, insects and mollusks are invertebrates


Aquatic environments

Diversity of all organisms decreases as acidity increases and dissolved oxygen decreases
If the pH in the water is below 5.0 there will not be many fish
Few insects and many worms may mean that the water contains little dissolved oxygen


What factors affect aquatic organisms

Chemical factors:
These are indicators if water quality-
Dissolved oxygen
Heavy metals
Plant nutrients such as nitrogen & phosphorus
Salts such as sodium chloride and magnesium sulfate
The concentration if chemicals in the environment is usually measured in parts per million (ppm)


Dissolved oxygen

Is essential for the health if aquatic life such as fish, insects and micro-organisms
Levels of dissolved oxygen depend on:
Turbulence due to wind or speed of water
Amount of photosynthesis by plants and algae in water
The number of organisms using up oxygen
5 milligrams per litre (5ppm) of dissolved oxygen will support most aquatic organisms


Factors that can affect the amount of dissolved oxygen is an increase in...

Phosphorus and nitrogen in the water
This can cause increased growth of algae and green plants
As most algae in green plants grit more die
Bacteria is decomposing the dead material
The bacteria increases the usage of dissolved oxygen in the water
When the dissolved oxygen decreases many aquatic organisms decrease


Spring acid shock

The Canadian Shield has been affected by acid precipitation which causes acid deposition
In areas where acid precipitation is a problem it deposits into snow and ice in the winter. In the winter the snow and ice melt, therefor the water flows into streams and lakes... This is known as spring acid shock


Pesticides have changed:

Because pesticides may be toxic scientists are designing new ones that last only one growing seasons and are broken down by bacteria
Some insects have become resistant to pesticides and build their generation to e resistant as well
Not all pesticides break down entirely in the environment, this causes the tissues of organisms to accumulate and cause serious health problems



Used to compare toxins...
LD stands for lethal does and 50 stands for 50%
It is the amount of a substance that causes 50% of a group of test animals to die if they are given a specified does if a substance


Heavy metals

They can be toxic
Mercury belongs to this group
They are called heavy metals because they have a density greater than 5g/cm3 this means they are five times more heavier than an equal volume of water
These metals accumulate into the bodies if organisms and cause health problems


Monitoring air quality

Determined in two ways:
Measuring levels of pollutants in the air
Estimating the amount of emissions from pollution sources


Sulfur dioxide

Is an air pollutant that forms smog and acid rain
Can affect respiratory system and irritate eyes
Major source is industrial processes such as oil and gas industry, burning fuels such as coal, oil and natural gas
Combine with oxygen to form nitrogen which is harmful to plants, animals and non living objects (major air pollutants)



Are used on industrial and electrical generating plants to reduce sulfur dioxide emissions
Use limestone (calcium carbonate) to convert sulfur dioxide to gypsum
Combine with oxygen to form nitrogen which is harmful to plants, animals and non living objects (major air pollutants)
Remove up to 99% of sulfur dioxide emissions



A useful product that is recovered and used in manufacturing


Nitrogen oxides

Also air pollutants which form smog and acid rain
Like sulfur dioxide that affect our health by irritating the respiratory system and eyes
Formed mainly from the combustion in vehicles


Carbon monoxide

A colourless and odour less gas and is known as the silent killer
Main source is form human activity in noter vehicles
Other sources include: combustion of wood, natural gas, industrial processes, airplanes and forest fires
Dangerous because it reduces the amount of oxygen carried by the blood if inhaled and may result in headaches, sleepiness, chest pains, brain damage and even death


Catalyst converters

Are used in vehicles to convert carbon monoxide into carbon dioxide
This creates a problem in the high levels of carbon dioxide being released, in increasing greenhouse gases and global warming


Ground level ozone

Layers of ozone in the upper atmosphere protect the earths surface from harmful chemicals
However ground level ozone is a harmful pollutant
Ozone is a odourless and colourless gas made up of 3 oxygen atoms
At ground level the ozone reacts with oxygen, nitrogen oxides and volatile organic compounds
Ozone pollution is a problem mainly in larger cities during the summer where there are many automobiles and industries
Ozone is harmful to people with lung diseases ( asthma)
Ground level ozone can seriously affect crops such as wheat, soybeans and onions
Ozone can also cause materials such as plastic to deteriorate more rapidly


Carbon dioxide

Is naturally present in the air so it is not normally considered a pollutant


The greenhouse effect

When radiant energy from the sun reached earths surface much of it is reflected back into space. Some of the energy is trapped near the Earths surface by a layer of gases that act like glass in a green house


Greenhouse gases

Gases in the upper atmosphere which trap the heat are called greenhouse gases
Water vapour, carbon dioxide, methane and nitrogen oxides are all greenhouse gases


The enhanced greenhouse effect

Effect that is made greater by human activities such as burning fossil fuels and clearing land that add the gases in more concentrated amounts to the atmosphere
Water vapour and then carbon dioxide contribute most to the enhanced greenhouse effect


Global warming

When greenhouse gases accumulate in the atmosphere the overall temp of the earths surface
Caused by:
Human activities- Burning fossil fuels ect.
Natural events-volcanic eruptions, forest fires ect.
Some countries are attempting to reduce carbon dioxide emissions:
Windmill farms- use power turbines rather than burning fossil fuels
Forest projects- growing trees absorb the C02, reduces in environment


The ozone layer

Occurs in high in the earths atmosphere15-20 km above the surface
This ozone absorbs ultraviolet radiation which is a good thing
As the ozone layer became thinner over the years, more UV radiation is allowed to reach the earths surface, which is a bad thing. This can cause a harmful effect in organisms:
Increased risk if skin cancer in the cataracts in humans
Plankton in the sea are sensitive to UV radiation could die off of exposed to large amounts. This would affect all the animals that feed on plankton



Scientist Believe that the thinning of the ozone layer is a result of chemicals humans call chlorofluorocarbons (CFC's)
Have been used in refrigerators, aerosol cans ect.
When CFC's reach the upper atmosphere, UV radiation breaks chemicals down into substances such as chlorine that destroys the ozone. One chlorine atom can destroy 100000 ozone molecules
International agreements have been signed by many countries in an attempt to reduce CFC's


Parts per trillion

(ppt) is difficult and requires special costly equipment
Only extremely hazardous substances are measured to this level of concentration

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