Environmental Problems, Their Causes, and Sustainability 1

xHOW WOULD YOU VOTE? Should households and businessesbe charged for the amount of mixed waste pickedup but not charged for pickup of materials separated forrecycling? Cast your vote online at http://biology.brookscole.com/miller14.Case Study: How Much Wastepaper Is BeingRecycled? Encouraging NewsRecycling paper has a number of environmental andeconomic benefits and is easy to do.Paper (especially newspaper and cardboard) is easy torecycle. Recycling newspaper involves removing itsink, glue, and coating and then reconverting it to pulpthat is pressed into new paper. A variety of affordablehigh-quality recycled papers are available to meetmost printing demands (including this book).About 42% of the world’s industrial tree harvest isused to make paper. With 4.6% of the world’s population,the United States consumes about 30% of theworld’s paper and buries or incinerates more than halfof this paper. Currently the United States recycles about49% of its wastepaper (up from 25% in 1989) and 70% ofits corrugated cardboard containers. At least 10 othercountries recycle 50–97% of their wastepaper and paperboard,with a global recycling rate of 43%. Bad news.Despite a 49% recycling rate, the amount of paperthrown away each year in the United States is morethan all of the paper consumed in China. Also, about95% of books and magazines produced in the UnitedStates are printed on virgin paper. Some individualsand groups have been letting magazine and book publishersknow that they will no longer buy their productsunless they greatly increase their use of recycled paper.One problem associated with making paper is thechlorine (Cl 2 ) and chlorine compounds (such as chlorinedioxide, ClO 2 ), used to bleach about 40% of theworld’s pulp for making paper. These compounds arecorrosive to processing equipment, hazardous forworkers, hard to recover and reuse, and harmful whenreleased to the environment. However, a growingnumber of paper mills (mostly in the European Union)are replacing chlorine-based bleaching chemicals withchemicals such as hydrogen peroxide (H 2 O 2 ) or oxygen(O 2 ).Environmentalists propose that governments requirepaper companies to use labels that list the recycledcontent of paper products and whether the paperwas bleached with chlorine or a chlorine-free process.In 2000, 90% of the copier paper purchased bythe U.S. government (one of the country’s largestbuyers) had 30% recycled content. In 2002, Staples, amajor office supply company, pledged to phase outpurchases of paper products from endangered forestsand achieve an average of 30% postconsumer recycledcontent in all paper products it sells. Managementwill provide annual reports on progress towardthese goals. The company adopted the goals in responseto a 2-year grassroots effort called The PaperCampaign, a coalition of dozens of citizens’ groupsdedicated to protecting forests and increasing the useof recycled paper. Bottom-up political action and usingthe power of the pocketbook work.Case Study: Is It Feasible to Recycle Plastics?Some ProblemsRecycling many plastics is chemically and economicallydifficult.Plastics are made of various types of large polymer orresin molecules made by chemically linking monomermolecules (petrochemicals) produced mostly from oiland natural gas (Figure 24-10).Currently, only about 10% by weight of all plasticwastes in the United States are recycled, for three reasons.First, many plastics are difficult to isolate fromother wastes because the many different resins used tomake them are often difficult to identify and someplastics are composites of different resins. Most plasticsalso contain stabilizers and other chemicals thatmust be removed before recycling.Blow molding(hollow objects)ProductsBottles, milk jugs,soda bottles,drums, containersSource MaterialsNatural gas Petroleum CoalRefiningFeedstocksMonomers (small molecules)Molding(solid objects)PolymerizationPolymersResins (giant molecules)ManufacturingProductsAppliancehousings, CDs,toys, plastic parts,aircraft, boatsExtrusion(flat, rolled, andtubular shapes)ProductsVinyl siding,plastic film andbags, pipeFigure 24-10 How plastics are made. (Adopted from Society ofthe Plastics Industry)http://biology.brookscole.com/miller14543