(完整版)环境科学交叉关系学科课后题答案第十七、十八章

CHAPTER 17

1. As illustrated in figure 17.2, the waste generation rates of people are directly related to their economic condition.

Nation with high standards of living and productivity tend to have more municipal solid waste per person than less-developed countries.

3.

1)The remaining numbers of landfills in US are declining as some small, poorly run landfills are

closed as they fail to meet regulations. Others are closed due to full capacity. Therefore, new, modern landfills are in urgent need, especially in metropolitan cities(LA, NY, Toronto).

However, it is difficult to find a geologically suitable site and building new ones often receive local opposition.

2)What’s more, a modern landfill is becoming increasingly more complex and expensive, and it

is sometimes no more cost effective compared to incineration. Experts also suggest that unless further steps are taken to detoxify landfilled materials, they will place burden on upcoming generations to address future impacts.

3)Landfills may present long-term threats to groundwater and surface water that are

hydrologically connected. Leachate is of particular concern, if the landfill system is not properly sealed, the rain or connected water source may leak through buried trash, dissolving and carrying hazardous materials with it, and pose the major threat to the current and future quality of groundwater.

4)There is a problem about the air pollution too. Methane produced by decomposing waste

should be collected and treated, and they can be used to produce heat or to generate electricity, or they might enter atmosphere and become a kind of greenhouse gas.

5.

1)Design changes to soft drink bottles and milk jugs can keep out more than one hundred

million kg of plastic out of the waste stream per year.

2)Manufacturing processes have been changed in many industries to reduce the amount of

waste produced. This kind of change could be done by paying more attention to incidence like leaks, spills and accidents.

3)Purchasing decisions can significantly reduce the amount of waste produced. Choosing to

purchase things that have reduced packaging waste, not only could this reduce the amount of waste , but also might it encourage the producer to use less in packaging.

4)Using materials in such a way that waste is not generated is an important means of curbing

waste. Using less-hazardous alternatives and sharing products that contains hazardous chemicals, following the label directions and using the smallest amount necessary are way to reduce waste or its toxicity

5)Reusing items is a way to reduce waste at the source because it delays or prevents the entry

of reused items into the waste collection and disposal system.

7.Several kinds of program have contributed to the increase in recycling rate.

Container laws and mandatory recycling laws in many states provide an incentive to recycle and