Topic 3.0 harmful substances are spread in the environment Flashcards
Factors of the direction and distance of airborne pollutants
Pollutants properties, wind speed, and the direction of prevailing winds
Transport in air
Release of the chemical at the source
Dispersion if chemical in the atmosphere
Deposition if the chemical in soil or water
The distribution of airborne pollutants may be limited by lack of wind, precipitation.
The pollutant will be depositors closer to its source if it is carried to the ground by rain or snow
It is hard to identify a pollutant that had travelled thousands of kilometres. Due to the movement of these chemicals it has become an international problem in which they are signing agreements to limit the amount of airborne pollutants.
Transport in groundwater
Water that soaks into soil moves first into a zone near the surface where the soil grains contain both air and water (water table) Next it will move deeper and enters a zone where all the spaces are filled with water (groundwater)
Groundwater can move sideways, up and down
The water can exonerate concentrated with substances such as lead and creates problems to drink the water and use for other purposes
Factors that affect the rate of groundwater
The soil had pores.. These pores are tiny spaces between soil grains that are sometimes tightly packed that the pores are not connected. In this case the water cannot flow through the soil as easily. If the pores are connected the soil is permeable and transports pollutants through the water more easily.
Some substances that contaminate groundwater
Minerals in rocks and soil: iron, calcium
Organic substances ( natural or human made): pesticides, solvents
Leached from landfill sites: heavy metals (mercury)
Leak from underground storage or pipelines: gasoline, oil
Inorganic substances( industrial processes ect.): salt, fertilizers
Improper micro-organisms: bacteria, viruses
Household chemicals: detergents, nitrates
Transport in surface water
Potentially hazardous chemicals can enter the surface water from different sources such as air, groundwater, runoff from different sites, and the outflow from sewage treatment plants
These chemicals can be dispersed throughout the surface water by these sources becoming attached to solids and can build to in lakes or river bottoms, affecting organisms
We need to track and monitor the water continually due to this issue
Transport in the soil
Water landing on a field or your yard does four things:
Some evaporates
Some soaks into the soil and is taken by plants
Some runs into the street or stream
Some soaks though the soil, moves downwards, dissolves substances in the soil and carries them along
These substances are called leachate
Composition of soil can affect this: if packed closely- harder to leachate, if not packed- most likely to leachate compared to packed clay
Acids or other hazardous chemicals in the soil can neutralize organic substances such as broken down leaves that become organic material
Transport of hydrocarbons in soil
Contamination of soul by hydrocarbons is a problem throughout Canada
Hydrocarbons are from vehicles and in industry… They contaminate by being carried through water in the soil and spread over a wide area. They can concentrate inside the pores of the grains and not travel very far but cause a difficulty to clean up
Most hydrocarbons are toxic to plants, animals and humans
Concentration of pollutants in the environment can be changed using different techniques such as..
Dispersion, dilution, biodegratuon, phytoremediation and photolysis
Dispersion
The scattering of a substance away from its source
Ex. If you spilled to much fertilizer on your lawn you could disperse it throughout the soil
Dilution
Reduces the concentration of a pollutant by mixing the polluting substance with large quantities of air or water
Ex. If you drip some bleach into a sink of water it will dilute into the water and spread the molecules
What dilutes or disperses a chemical quickly?
A fast flowing river or air mass
Dilution or dispersion combined with another clean-up process such as biodegration can be very effective
Biodegration
Nature uses living things to clean up the environment
Organisms such as earthworms, bacteria and Fungi help the biodegration of most organic substances degrade
Algae live at the soil surface can use the broken down substance as organic compounds through photosynthesis for food
Carbon atoms in these molecules can be used to build compounds such as carbohydrates and protein
Aerobic and anaerobic biodegration
Aerobic: uses oxygen in the air to grow and produce bacteria for breakdown
Anaerobic: without oxygen in the air to thrive the breakdown with bacteria
Factors affecting biodegration
Slow biodegration in the winter due to little bacteria growth
Other factors other than temp are soil moisture, pH, oxygen supply and nutrient availability
You can plant vegetation to help with the biodegration process
Phytoremediation
Green plants can be used to remove or degrade hazardous materials
It reduces the concentration of harmful chemicals in the soul or groundwater
Plants can be used to clean up metals, hydrocarbons, solvents, pesticides, radioactive materials, explosives and landfill leachates
Photolysis
The breakdown of compounds by sunlight. Some substances degrade from exposure to light
Ex. Photodegradable plastic: problem is that it will not break down if buried and out of sight from sunlight
Biomagnification
Increase in concentration of a chemical or element as it moves up the food chain
Ex. Mercury: comes from emissions from coal-fires power plants ect. The mercury falls into fresh or salt water where bacteria join it to an organic molecule that alga can absorb
After this point mercury enters the good chain through the alga and leads to insects, green plants and fish. Eventually making it onto our plates and harming humans
Mercury contaminated water is a problem in Canada’s Great Lakes
Crude oil
A mixture of many chemicals
Contains hundreds of different molecules in all shapes and sizes
Some in crude oil contain nitrogen, oxygen and sulfur
Crude oil cannot be used right when bit comes out from the ground.. It had to be refined through a process
Crude oil spills
Exxon Valdez is a good example…
Occurred in prince William sound and changed the beauty of the lake
The small molecules oil spilled and dispersed into the air and water
Tar balls of heavy hydro garçons were washed ashore or sank into the sediment under the water
This is a long term problem and caused a major impact on the environment
Impact of oil spills on plants and animals
Floating algae can be killed, invertebrates near shore could not survive due to decreased oxygen, loss of food and the toxic effect of hydrocarbons
Fish eggs and young fish were sensitive to the oil and died
Adult fish could escape by swimming away but the lost their habitat and good resources
Seabirds and mammals can become covered in oil so many of them would die as well
Impact of the oil spill on people
Many commercial fishers could no longer sell fish
People who relied on wildlife for food ha to purchase food instead
Tourism decreased due to loss of recreation in an oil spill area
All of these effects caused a long term clean up to fully repair most of the damages done by the spill
Oil spill clean up
Booms am be used to clean up and obtain the spills in water
Ground spills occur too and have different procedures to clean up the spills
Hazardous chemicals include
Household cleaners Personal hygiene products Pet-care products Paint and paint products Pesticides and fertilizers Automotive fluids
Government regulations
Designed to protect consumers and reduce the risks of transporting,storing,using and disposing of hazardous materials
MSDS’s
Material safety data sheets
They are a form of label that gives information about the harmful substance to the buyer of the product
If describes precautions that should be taken when handling, using, transporting and disposing of the product
It also provides details about heal effects and how to contain or store the product
New product regulations
Intended use, physical and chemical properties and active ingredient(s)
Instructions for use, safety precautions
Heal effects, environmental effects, toxicity to humans and first aid instructions in case of poisoning
Storage of hazardous chemicals
Leave all products in organizational containers (secured lids) and labels
In a location out of reach from children
Store in cool, dry, ventilated places
Don’t store flammable substances in glass containers or substances such as gasoline should be stored outside of the house
Store different substances on separate shelves from each other
Discard of containers that are leaking or substances that are old
Transportation of consumer goods
Should be placed in the trunk of a car where they will not fall over (secure)
Do not mix together hazardous household wastes when bringing to a collection site
Disposal if hazardous chemicals
Never pour wastes down the drain or into the soil
Do not throw them away in the garbage
If you do pour the substance down the drain it can enter into the sewage system it septic tanks and not be filtered, therefor they are entering into the surface water and harming the soil water, drinking water and even air
Hazardous waste collection sites
Found in almost all of Alberta communities
Wastes such as paints and fertilizers will be taken to theses sites for disposal
Materials that cannot be recycled will be safely packaged in large containers where they are sealed with later
Solid waste garbage
Some substances such as gasoline and oil can be recycled at a hazardous waste collection site
Take antifreeze to a recycling centre and don’t out it into the ground or drain where it will enter into your septic tank
Never place car batteries in a home garbage. They can be recycled
Take care or aresol cans, syringes, fertilizers, pesticides and paint products by putting them in a hazardous materials collection site
