■ Neutralizing the soil with a basic substance such as limestone (CaCO 3 ),
lime or calcium oxide (CaO), calcium hydroxide (Ca[OH] 2 ), or calcium
silicate (Ca 2 SiO 4 )
■ Reducing infiltration by rainwater by covering the soil
■ Constructing wetlands for bioremediation
■ Utilizing ion-exchange technology to remove hazardous metals
■ Using sulfate-reducing bacteria (acidophiles) in catchment basins—these
ancient bacteria are also able to reduce some hydrocarbons (e.g., benzene)GLOBAL MINERAL RESERVES
Two billion tons (1.8 billion m.t.) of minerals are extracted and used each year in
the United States (about 10 tons [9.1 m.t.] for every American). At the same
time, the United States imports more than 50% of its most needed minerals. As
mineral reserves become depleted, lower grades of ore are mined, which causes
more processing and consequently more pollution.
The United States, Germany, and Russia represent 8% of the world’s population,
yet they consume 75% of the most widely used metals, with the United States
consuming 20%.
Future Mineral Supplies
As the global economy grows and evolves in the 21st century, emerging
technologies will require mineral commodities on a greater scale and in a larger
number of applications than ever before (e.g., advances in alternative energy
technologies, telecommunications, and in the aerospace and defense industries
have all been made possible by incorporating new applications of mineral
materials). Many mineral commodities used in emerging technologies are rare
and their known resources are limited.
As standards of living rise around the world, there is greater demand for
durable goods and products manufactured from mineral materials. Every year,
each person in the U.S. requires more than 25,000 pounds of new nonfuel
minerals to make the items we use every day.
Mineral Commodity Average Amount Required for Each American Over A
LifetimeAluminum 5,677 pounds (2,575 kg)