6.3 - Hazards and Benefits of compounds

Mercury - Description An element present naturally in the environment at low levels. Added to the environment by burning coal. Mercury becomes concentrated (more in a smaller space) in the environment. Bacteria in the environment change mercury into a more dangerous chemical (METHYLMERCURY)

Mercury – helpful characteristics Useful in pulp and paper mills (used to manufacture chlorine to bleach paper). Used in some thermometers

Mercury – harmful characteristics Toxic – causes mercury poisoning (rashes, numbness, tremors, slurred speech, tooth loss, reproductive issues and birth defects) Can build up to dangerous levels in food in the environment (e.g. fish) Lasts a long time in the environment (spills are hard to clean up)

CFC’s (Chlorofluorocarbons) – description Gases that are not harmful to humans (non-toxic and nonflammable), but can do damage to the environment (the ozone layer).

CFC’s – Helpful characteristics Was used in refrigeration units (fridges and air conditioners) Was used in aerosol spray cans and some asthma medications (propellant)

CFC’s – harmful characteristics Destroys the ozone layer (a layer of protective gases surrounding the Earth that prevents UV rays from reaching the Earth). Created a hole in the ozone layer that may take until 2025 to completely close.

Benzene - Description A hazardous chemical that is both toxic can flammable Can be used safely with precautions A regulated substance (special permits must be obtained for its use).

Benzene – helpful characteristics Used to make dyes, detergents, medications (e.g. aspirin), acetate

Benzene – harmful characteristics Toxic (cancer hazard) Flammable

Pesticides (and POP’s (persisitant organic pollutants)– Description Any chemicals used to control a “pest” – e.g. herbicides, insecticides. POP’s do not break down in the environment and can build up in body tissues

Pesticide and POP’s – helpful characteristics Pesticides are used to eliminate unwanted organisms from an area in which they can cause problems – e.g. DDT is an insecticide that is used to kill mosquitoes and is effective in helping to prevent the spread of diseases like malaria that are transmitted by mosquitoes.

Pesticides – harmful characteristics Persistant organic pollutants build up in the environment and can reach toxic levels in animals Pesticides can harm potentially useful organisms in the environment if not specific to the pest

1. Is water a chemical? explain All matter is made of chemicals. If it contains atoms, it is a chemical.

4. List 3 reasons why hazardous chemicals continue to be produced in our society. They are useful for an important process There is no other alternate chemical that can be used When used carefully and under controlled conditions, their hazards can be controlled.

5. How can mercury in a dry cell end up in the environment? When dry cells are thrown into the garbage, their outer casings can begin to break down. The mercury inside the cells can then seep out and get into the water or soil around the landfill area. If water from the landfill is able to reach a waterway, the mercury can then move to different areas.

9. What are 3 uses of benzene? Used to make acetate Used in dyes Used in detergents Used to make aspirin

10. Benzene is a regulated substance. What does this mean? A ‘regulated substance’ is one that must be used according to strict guidelines that are regularly reviewed and revised.

11. What ways of handling benzene help it to be used safely? It must be kept in sealed systems, and workers must wear masks with activated charcoal filters.

14.In the future, will you recycle cellphone batteries or throw them out? Cellphone batteries may contain hazardous chemicals (e.g. mercury, cadmium, lead) which can escape from the casing of the battery and enter the atmosphere. These chemicals can reach toxic levels in organisms in the environment.

15. How are pollution in the environment and human health related? Pollutants in the environment can build up in organisms in the environment. As animals that are higher on the food chain eat these organisms, the toxins build up in larger levels. Humans are the top of our food chain. Eating organisms with pollutants in them can lead to poisoning.