Environmental Flashcards
How is glass recycled?
Crushed, melted, molded into new products.
What are the advantages of recycling glass?
Reduces energy costs
How are plastics recycled?
- heated in absence of air
- split up into monomers (pyrolysis)
- separated by fractional distillation
What are the benefits of recycling plastics?
- Reduce the amount made
* save crude oil reserves
What are the drawbacks of recycling plastics?
- Mixtures of plastics are weaker
* Cost in sorting and melting
How are metals recycled?
• sorted, melted, reused as alloys
How is paper recycled?
- cleaned from ink and additives
- added to water to form slurry
- repulping: cellulose fibers separated
- bleached (for white paper), but causes reduced strength
What are the benefits of using landfills for waste disposal?
• it is efficient with large volumes
What are the drawbacks of using landfills?
- requires maintenance
* material dumped must be controlled
What are the benefits of open dumping?
- convenient
* inexpensive
What are the drawbacks of open dumping?
- air and ground pollution
* rodents and insects
What are the benefits of ocean dumping?
- source of nutrients
* convenient and inexpensive
What are the drawbacks of ocean dumping?
- pollutes the sea
* danger to marine animals
What are three organic soil pollutants and their sources?
- Hydrocarbons/VOCs: transportation, industrial processes.
- Agrichemicals: pesticides, herbicides, etc.
- PCBs: insulator in electrical equipment
What are some properties of Soil Organic Matter (SOM)?
- organic constituents of soil
- consists of plant/animal tissues; soil biomass
- serves as food for microorganisms
- humus
What are some properties of Humus?
- it is residue left after decomposition of organic material
- Biological: source of energy, nutrient elements
- Physical: humus helps the soil return moisture; provides good soil structure; dark color; absorbs heat
- Chemical: cation exchange capacity (bonds to nutrient cations); good for plants, not washed away; constant pH; metal ions don’t spread through ecosystem
What causes salinization in soil?
- through excess irrigation
* dissolved salts accumulate to toxic levels; prevent roots from taking up enough water
What are the constituents of soil?
• organic and inorganic matter
How is nutrient depletion created in soil?
- nutrients are absorbed while growing
- over-harvesting without letting soil recover nutrients
- use of fertilizers/ manure
How is soil pollution created?
- oil from transportation/ illegal dumping of engine oil
* use of pesticides/fertilizers reduces soil biodiversity
What are the advantages and disadvantages of using CFC alternatives?
- HFCs: non-flammable; non-toxic
* Hydrocarbons: flammable; toxic
What chemical reactions take place under UV light in the atmosphere with oxygen?
- O(2) [yields] 2O•
- O• + O(2) [yields] O(3)
- O(3) [yields] O(2) + O•
- O(3) + O• [yields] 2O(2)
What affects ozone concentration?
• Oxides of Nitrogen and CFCs
What are the effects of decreased ozone levels?
- increase in sunburn
- growth of plants inhibited
- increase in eye cataracts
