Benchmark 8B
The Designed World: Materials and Manufacturing
Grades 3-5, page 189

Discarded products contribute to the problem of waste disposal. Sometimes it is possible to use the materials in them to make new products, but materials differ widely in the ease with which they can be recycled.

NSES Content Standard F 
Science in Personal and Social Perspectives: Types of resources
Grades K-4, page 140
The supply of many resources is limited. If used, resources can be extended through recycling and decreased use.