Environmental Encyclopedia

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Environmental Encyclopedia 3

Recyclables

adults hunted in 2001, with overall hunting participation

dropping about 7% from 1996 to 2001. Wildlife watching

remained a popular outdoor activity and more than 66 milion

people age 16 or older fed, photographed, or observed wild-

life in 2001, spending some $40 billion on their wildlife

activities.

More adults participate in walking for pleasure than

any other recreational activity. Driving for pleasure, sightsee-

ing, picnicking, and swimming are also among top recre-

ational activities. Canoeing has been the fastest growing

activity over the past 30 years.

Outdoor recreation also stimulates tourism. In 2001,

almost 300 million recreation visits were made to our na-

tional parks. The United States has more than 778 million

acres (314 million ha) of publicly-owned recreation lands,

more than any other nation. Over one-third of the contigu-

ous United States is public recreation land; however, these

lands are not evenly distributed. Most of these lands are in

the sparsely populated western states. There are 8,373 acres

(3,391 ha) of public recreation lands per 1,000 people in the

West, whereas there is only 294 acres (119 ha) per 1,000

people in the northeastern states. Almost 91% of the public

lands area is administered by the federal government; 8%

by states, 0.7% by counties, and 0.4% by municipalities.

However, when number of sites, rather than acres, is consid-

ered, the recreation supply picture changes considerably.

Almost 62% of all recreation sites are municipal, whereas

only 1.6% of the sites are federal.

The private sector is also a major recreation supplier,

particularly for certain activities. For example, there are more

than 10,000 private campgrounds, 600 ski resorts, and 4,789

privately-owned

golf courses

in the United States.

Several important trends will affect the supply and

demand of future recreation opportunities in the United

States. Increasing populations, increasing ethnic diversity,

the aging of the population, changes in leisure time, dispos-

able income, and mobility will affect the demand for recre-

ation. The loss of open spaces;

pollution

of our lakes, rivers,

and coastlines; increasingly limited access to private lands;

and increasing liability concerns will make the task of meet-

ing future demand for recreation more difficult.

[Ted T. Cable]

ESOURCES

OOKS

Kelly, J. R. Recreation Business. New York: Wiley, 1985.

Kraus, R. Recreation and Leisure in Modern Society. 3rd ed. Dallas, TX:

Scott, Foresman, 1984.

The Report of the President’s Commission on Americans Outdoors, The Legacy,

The Challenge. Washington, DC: Island Press, 1987.

1177

THER

“National Park 2001 Visitor Use Summary.” National Park Service. [cited

July 9, 2002]. <http://www2.nature.nps.gov/stats>.

U.S. Fish and Wildlife Service. 2001 National Survey of Fishing, Hunting,

and Wildlife Associated Recreation. Washington, DC: U.S. Government

Printing Office, 2002.

Recyclables

Recyclables are products or materials that can be separated

from the

waste stream

and used again in place of raw

materials. Since colonial times, Americans have recycled a

host of materials, ranging from corn husks used for mattress

stuffing to old clothes used for quilts. Today, household

recyclables include newspapers, mixed waste paper, glass, tin,

aluminum

, steel,

copper

plastics

, batteries, yard debris,

wood, and used oil. Commercial recyclables include scrap

metals, concrete, plastics, corrugated cardboard, and other

nonferrous scrap material. The list of recyclables will likely

expand as technology meets a growing demand for more

recycling

in response to increased consumer awareness and

waste disposal costs, dwindling

landfill

space, and more

stringent

waste management

regulations. The

Environ-

mental Protection Agency

(EPA) has emphasized the im-

portance of diverting recyclables from the waste stream by

endorsing integrated waste management, in which

munici-

pal solid waste

is managed according to a hierarchy of

source reduction, recycling,

solid waste incineration

, and

landfilling.

Programs to divert household recyclables from the

waste stream are typically developed and implemented at

the local or community level, while commercial recyclables

are usually collected by private industry. Collection and prep-

aration methods vary among recycling programs. Some com-

munities have implemented curbside collection programs

that require households to separate recyclables from their

waste and sort them into segregated containers. Other curb-

side collection programs pick up recyclables separated from

household waste

but commingled together. Still other

communities are responsible for picking out recyclables

mixed in the waste stream. In some municipalities, recycla-

bles are sorted and prepared for processing or market at a

Materials Recovery Facility (MRF). Most MRFs rely on

workers to hand-sort recyclables, though some also use sort-

ing equipment, including magnets for removing metals and

blowers for sorting plastics. Plastics are also hand-sorted

according to resins identified by a voluntary coding system

consisting of a triangular arrow stamp with a number in the

center and letters underneath that identify the seven major

types of plastic resins used in containers. Other equipment

exists for size reduction (shredding or grinding), weighing,

and baling recyclables.

Environmental Encyclopedia 3

Recycling

Increasing both the type and quantity of recyclables

are goals of many states. In 1999, recycling (including

com-

posting

) diverted 64 million tons of material away from

landfills and incinerators. That’s nearly double the amount

diverted in 1990 of 34 million tons. Batteries had the highest

recovery rate of any recyclable; almost 97% of all batteries

were recycled. Slightly more than 41% of all paper and

paperboard products were recycled and almost 40% of all

plastic drink containers made their way to recycling centers,

a major improvement over the last decade or so. An estimated

27% of glass was recovered from the waste stream. Approxi-

mately 54% of aluminum packaging was recovered for recycl-

ing. Recyclables also exist in the form of durable goods,

which are products that have a lifetime of over three years.

These are usually bulky items, such as major appliances,

which are not mixed with the rest of the waste stream.

Ferrous metals can be recycled from refrigerators, washing

machines, and other major appliances, known as “white

goods.”

Recyclables are commodities, and markets for these

commodities fluctuate dramatically. The dynamic nature of

markets is a key factor in whether a recyclable is actually

recycled instead of being disposed in a landfill or combusted

in an incinerator. Municipalities involved in recycling pro-

grams must deal with rapid shifts in the market for recycla-

bles. For example, the demand for a particular recyclable

may drop, reducing the price and forcing the municipality

to pay for the material to be taken away for recycling or

disposal. Consequently, recycling must compete with raw

material markets, as well as waste disposal methods.

An additional advantage of recycling is that it helps

reduce greenhouse gas emissions. These emissions can im-

pact the earth’s

climate

. In 1996, it was estimated that

recycling of

solid waste

in the United States alone may

have prevented the release of 33 million tons of

carbon

into

the air, about the same amount as emitted by 25 million

cars in one year. See also Garbage; Green packaging; Munici-

pal solid waste; Solid waste incineration; Waste reduction

[Marci L. Bortman]

ESOURCES

ERIODICALS

Pollock, C. S. “Building a Market for Recyclables.” World Watch 1 (May–

June 1988): 12–18.

THER

“Basic Facts, Municipal Solid Waste” U.S. Environmental Protection Agency.

[cited July 8, 2002]. <http:www.epa.gov/epaoswer/non-hw/muncpl/

facts.htm>.

U.S. Environmental Protection Agency. Characterization of Municipal Solid

Waste in the United States: 1990 Update. Washington, DC: U.S. Govern-

ment Printing Office, 1990.

1178

U.S. Office of Technology Assessment. 1989. Facing America’s Trash: What

Next for Municipal Solid. Washington, DC: U.S. Government Printing

Office, 1989.

Recycling

Recycling waste is not a new idea. Throughout history,

people have disposed

garbage

in myriad ways. They fed

household garbage to domestic animals. Scavengers gleaned

the

waste stream

for usable items that could be fixed, then

sold or traded for other goods and services. Homemakers

mended clothing, and children grew up in hand-me-downs.

Durable goods were just that; goods that could be reused

until their durability wore out. These practices were not due

to a desire to reduce the waste stream, but rather a need to

produce products from all available resources. Modern soci-

ety has moved away from such straightforward recycling

practices, choosing instead to toss out the old and buy new

goods. This throwaway society now faces a trash crisis.

The volume of

solid waste

generated in the United

States has continued to increase, along with the cost of

building landfills and

incineration

facilities. Recycling some

of this material into new uses saves existing

landfill

space,

conserves energy and

natural resources

, reduces

pollution

and saves tax money. Recycling can provide new jobs, create

new industries, and contribute to the increase in the GNP.

Instead of referring to what people discard every day as

garbage, advocates of recycling emphasize the need to refer

to waste products as Post Consumer Materials (PCMs) and

consider them renewable resources for various manufacturing

processes.

The challenge of collecting adequate volumes of recy-

clable materials in a form ready for manufacturing into new

products is a formidable task. Unlike raw materials that are

extracted from the earth or manufactured in a lab, PCMs

are mixed materials, and are sometimes contaminated with

toxic and non-toxic residue. PCMs must be cleaned and

source-separated at the individual household and business

level. Once the materials are made available at the point

of generation, they must be collected and transported to a

collection site, usually referred to as a Materials Recycling

Facility (MRF). At this location, materials are processed to

make

transportation

easier and increase their value. Glass

is separated by color,

plastics

are pelletized, and paper is

baled. Other materials may be cleaned and reduced in vol-

ume, depending on the equipment available. The exceptions

to this rule are single materials collected and transported

directly to the point of use, such as newspaper collected at

a drop off site and transported to a local insulation manufac-

turer. The existence of an MRF enhances the recycling

process because it allows large volumes of materials to be

amassed at a single location, making marketing of PCMs

Environmental Encyclopedia 3

Recycling

more profitable. If manufacturers know that there are ade-

quate volumes of high-quality raw material consistently

available, they are more likely to agree to long-term purchas-

ing contracts.

Manufacturers are being encouraged to retrofit, or re-

tool, their manufacturing processes in order to use PCMs

instead of raw materials. Many glass manufacturers now use

cullet (cut glass) instead of silica and sand to make new glass

containers, and some paper manufacturers have installed de-

inking equipment in order to manufacture paper from used

newsprint instead of wood pulp. Once the initial expense of

equipment change has been absorbed, such changes can

reduce costs. But these are long-term investments on the part

of manufacturers, and they must be ensured that recycling is

a long-term commitment on the part of consumers and

communities.

Recycling begins with people, and the biggest chal-

lenge for recycling lies in educating and motivating the public

upon whom successful

source separation

depends. Except

in rare circumstances recycling is a voluntary act, so the

attitudes, knowledge, and feelings of the participants are the

key to sustained recycling behavior. It has been found that

people will change their behavior to protect the health of

their families, the value of their property, and their own

self-image, and recycling has often been justified in these

terms. Once the rationale to begin recycling has been shared

with community residents, a program for making recycling

convenient and inexpensive must be institutionalized.

Curbside recycling is currently the most desirable re-

cycling option, primarily because of its convenience. Bio-

Cycle Magazine reported in April of 1999 only nine states

with fewer than 10 curbside recycling programs. These are

usually commingled, or mixed, systems. Residents clean and

prepare glass, cans, paper, and plastic, before putting them

together in a container and placing them at the curb. Most

waste haulers pick up the

recyclables

on the same day as

the rest of the waste, separating them into bins on the truck

right at the curb. In more rural areas, where homes are too

far apart, recycling often takes place at a drop off center.

This is usually a tractor trailer with separate bins, which is

hauled directly to an MRF when it is full and replaced by

an empty trailer. Research has shown that the best system

is one where curbside recycling is offered, but a drop-off

site is also available as a backup in case residents miss their

recycling day. In some communities there is a weekly or

monthly drop-off. Trucks from different industries use a

convenient parking lot and residents are encouraged to bring

their recyclables to company representatives. Some commu-

nities also have buy-back centers where residents can sell

PCMs to a broker who in turn sells the material to manufac-

turers.

1179

Many towns now have curbside recycling pro-

grams with trucks picking up recyclables on a

weekly basis. (Photograph by Robert J. Huffman. Field

Mark Publications. Reproduced by permission.)

In addition to residential recycling there is office or

business recycling. Office paper recycling programs are usu-

ally set up so office workers separate the paper at their desks.

The paper is taken regularly to a location where it is either

baled or picked up loose and transported to a manufacturing

plant. Offices that generate a large amount of white office

paper can collect and market the paper directly to paper

manufacturers. Smaller offices can cooperate with other busi-

nesses, contracting with paper manufacturers to pick up

paper at a central location. Another example of business

recycling is the recycling of corrugated cardboard by groceries

and clothing stores. These businesses have been breaking

down boxes and baling them on site for pickup by collection

trucks.

Dry cleaning

establishments are currently taking

back hangers and plastic bags from their customers for recycl-

ing. Businesses of many kinds have begun to realize that

positive publicity can be achieved through their recycling

efforts, and they have been increasingly inclined to partic-

ipate.

One of the biggest challenges to recycling in the future

is market development. For communities near to cities that

have major manufacturers taking PCMs, marketing is not

a problem. For smaller more rural communities, however,

different strategies must be developed. In some cases a well

Environmental Encyclopedia 3

Red tide

run MRF that brokers recycled materials is adequate. In

other cases, it may be necessary to search for local markets

to utilize PCMs, such as the use of newspaper as animal

bedding. Newspaper collected and processed within the

community can be sold to local farmers at a lower cost less

than straw or sawdust. Another approach is encouraging a

niche industry to locate nearby, such as a small insulation

contractor who is promised all the post-consumer newsprint

from the community. Ultimately, recycling will not be suc-

cessful unless consumers buy products made from PCMs.

Products made from these materials are becoming easier to

find, and they are more clearly marked than in the past,

though some green or earth-friendly product labeling has

been controversial. Recycling advocates have argued that

such labeling should not only say that the product is made

from recycled material, it should also note what percentage

of the material is post consumer waste, as opposed to manu-

facturing waste.

Many states are encouraging recycling through legisla-

tion. According to the Container Recycling Institute in 1999

10 states had bottle bills requiring stores to take back beer and

soft drinkbottles and cans, giving consumers a refund. Certain

states have banned all compostable materials from landfills in

order to force

composting

. In some states, daily newspapers

are required to use a certain percentage of recycled paper in

order to publish. These and other legislative steps have en-

hanced the recycling movement nationwide. States with the

highest recycling rate of 40% or higher include Maine, Min-

nesota, New York, South Carolina, South Dakota, and Vir-

ginia according to a report in BioCycle magazine in 1999.

Alaska, Montana, and Wyoming have the lowest recycle rate

of 9% or less according to the report. The majority of states

(40) recycle between 10 and 39% of materials. No data was

available for Idaho.

According the

Environmental Protection Agency

(EPA) in 2002, U.S. consumers recycle approximately 28%

of all waste. The highest recycle rate is for steel packaging,

with 57% being recycled.

Aluminum

drinking cans are recy-

cled at a rate of 55%, compared to 40% of plastic soft drink

bottles. The paper recycling rate is 42%, and 52% of appli-

ances meet with the recycler. The EPA sponsors a free

voluntary program to all U.S. organizations, called

WasteWise, to encourage and track the results of corporate

recycling programs.

The growing tonnage of computers, computer moni-

tors, and television sets that overpower municipal landfills

is an increasing problem that demands resolution. An esti-

mated 70% of

heavy metals

found in third millennium

landfills comes from digital hardware. Eight pounds (3.6

kg) of

lead

are contained in a single cathode ray tube (CRT)

monitor, contributing to the threats of lead contamination.

In May of 2002 the EPA proposed a recycling program to

1180

control this high-tech waste, including a provision to classify

CRT computer monitors as reusable waste products. The

necessity for these measures is evident in consideration of

the 500 million computers in use worldwide, which contain

an estimated 1.58 billion lb (716 million kg) of lead and

632,000 lb (287,000 kg) of

mercury

. According to EPA

estimates the number of discarded computers between 2002

and 2007 might reach 250 million units in the United

States alone.

Equally critical is the problem of

battery recycling

Growing concerns over poor battery recycling practices by

consumers are well founded because they are classified as

toxic waste, with mercury and lead contamination the most

serious problems caused by improper battery disposal. Yet

rarely are batteries disposed of accordingly. Most nonre-

chargeable batteries are tossed in the trash where they end

up in the landfills. The use of rechargeable batteries offers

a very effective solution to alleviate much of this problem,

because each rechargeable battery has a life cycle equal to

hundreds of nonrechargeable batteries; some rechargeables

have a life cycle of 1,000 recharges. Because of poor disposal

practices, every rechargeable battery protects the landfill

from potential contamination by hundreds of batteries.

The

National Recycling Coalition

is a nonprofit orga-

nization that provides leadership and coordination at the na-

tional level, sponsoring events, scholarships, and educational

programs to encourage effective recycling practices. See also

Container deposit legislation; Municipal solid waste; Solid

waste recycling and recovery; Solid waste volume reduction;

Transfer station; Waste management; Waste reduction

[Cynthia Fridgen]

ESOURCES

OOKS

BioCycle: Journal of Composting and Recycling. JG Press.

Carless, J. Taking Out the Trash: A No-Nonsense Guide to Recycling. Washing-

ton, DC: Island Press, 1992.

Coming Full Circle: Successful Recycling Today. New York: Environmental

Defense Fund, 1988.

Pollock, C. Mining Urban Wastes: The Potential for Recycling. Washington,

DC: Worldwatch Institute, 1987.

Recycling and recovery, solid waste

see

Solid waste recycling and recovery

Red tide

Red tide is the common name for phenomenon created

when toxic algal blooms turn seawater red, killing marine

life and making water unsuitable for human or animal use.

Environmental Encyclopedia 3

Red tide

Red tides are caused by several

species

of dinoflagellates

and diatoms, microscopic unicellular

phytoplankton

that

live in cold and warm seas. A red pigment, called peridinin,

which collects light during

photosynthesis

, colors the water

red when large numbers of the

plankton

populate an area.

Red tides are a danger because the

toxins

released

by large numbers of these plankton can paralyze fish and

bioaccumulate in the tissues of shellfish and filter-feeding

mollusks. Predators of the shellfish, including humans, con-

sume the toxins causing paralysis and death.

Species of dinoflagellates that cause red tides generally

belong to the “red tide genera,” Gymnodinium and Gonyau-

lax. Though several are known to cause red tides, a single

red tide is nearly always tied to a specific species. This may

be the result of three factors. First, the conditions responsible

for the bloom may also cause the red tide species to reproduce

more rapidly than other phytoplankton, thus outcompeting

them for available nutrients. Second, the toxins excreted

may prevent the growth of other species. Or, behavioral

differences may give them competitive advantages.

Red tides have occurred periodically through recorded

history in seas around the world. The Red Sea is thought

to have been named for algal blooms back in biblical times.

However, in recent decades red tides have been more fre-

quent in areas where algal blooms have never been a problem.

The coast of Chile has reported red tides since the

beginning of the nineteenth century, and the Peruvian coast

has recorded red tides, which they named aguajes, since 1828.

They appear more frequently in the summer months when

the water becomes warmer, and they also seem to be associ-

ated with the

El Nin

current. Coastal up-welling events are

also known to be essential for the occurrence of Gonyaulax

tamarensis blooms in the Gulf of Maine.

Red tides have been plaguing the east and west coasts

of Florida on a nearly annual basis since at least 1947. Blooms

on the west Florida shelf are initiated by the Loop Current,

an annual intrusion of oceanic waters into the Gulf of Mex-

ico. Here, the toxic dinoflagellate Gymnodinium breve pro-

duces rather predictable blooms. The red tide is transported

inshore by winds, tides, and other currents where it may be

sustained if adequate nutrients are available.

In 1987 and 1988, red tide spread northward from

the Gulf Coast of Florida as far as North Carolina, where

it caused a loss of $25 million to the shellfish industry due

to brevetoxin contamination. This was the first time that G.

breve blooms were reported so far north, and it raises the

question of whether blooms will occur annually in this re-

gion. Also during the 1987–88 blooms, 700 bottlenose

dol-

phins

washed ashore along the United States Atlantic coast.

Red tides commonly occur along the northwest coast of

British Columbia, Canada, and as far north as Alaska and

along the Russian coast of the Bering Sea.

1181

Researchers blame the recent spread of red tides and

the occurrence of algal blooms, which ordinarily occur in

harmless low concentrations, on the increasing amount of

coastal

water pollution

. Sewage and agricultural

runoff

increase concentrations of nutrients, such as

nitrogen

and

phosphorus

, in coastal waters. This increase in nutrients

may create favorable conditions for the growth of red tide

organisms.

In April 1992, two fishermen suffered paralytic shell-

fish

poisoning

(PSP) within several minutes of eating a few

butter clams from Kingcome Inlet, British Columbia. In

August 1992, saxitoxin, another dinoflagellate toxin associ-

ated with PSP, was found in the digestive systems of dunge-

ness crabs caught in Alaskan waters. On Prince Edward

Island, Canada, in 1987, three people died and more than

100 others became ill from domoic acid-contaminated mus-

sels. Some of those who became ill from this toxin developed

amnesic shellfish poisoning, which still causes short-term

memory loss.

It is difficult to accurately predict when and where red

tides may occur, and how seriously they will contaminate

shellfish. Monitoring levels of toxins in shellfish meat and

population sizes of the dinoflagellates is important in pre-

venting widespread poisoning of humans. Any detectable

level of brevetoxin in 3.5 oz (100 g) of shellfish meat is

potentially harmful to humans. The U.S.

Food and Drug

Administration

(FDA) does not inspect shellfish growing

areas regularly, but relies on state agencies to monitor toxin

levels. In selected states, surveillance programs have been

established that randomly examine shellfish that have been

harvested in natural shellfish beds. Florida is the only state

that has a constant monitoring and research program for

both shellfish poisoning and dinoflagellate blooms that cause

poisoning. Monitoring for shellfish poisoning is costly, but

the expense may increase if red tides become more frequent

due to deteriorating coastal

water quality

. In April and

May of 1996, 158

manatees

in southwest Florida died from

an unusual type of red tide. In China from 1997 until 1999,

there were 45 red tides which wiped out 75% of the entire

stock of Hong Kong’s fish farms. This was an estimated

$240 million loss to Hong Kong’s ecomonic system. See

also Agricultural pollution; Bioaccumulation; Competition;

Marine pollution; Sewage treatment

[William G. Ambrose and Paul E. Renaud]

ESOURCES

OOKS

Taylor, D., and H. Seliger, eds. Toxic Dinoflagellate Blooms. Vol. 1. New

York: Elsevier North Holland, 1979.

Environmental Encyclopedia 3

Redwoods

ERIODICALS

Culotta, E. “Red Menace in the World’s Oceans.” Science 257 (1992):

1476–1477.

Konovalova, G. V. “Harmful Dinoflagellate Blooms Along the Eastern

Coast of Kamchatka.” Harmful Algae News 4 (1993): 2.

Taylor, F. J. R. “Artificial Respiration Saves Two From Fatal PSP in

Canada.” Harmful Algae News 3 (1992): 1.

Redwoods

There are three genera of redwood trees, each with a single

species

. The native range of the coast redwood (Sequoia

sempervirens) is a narrow 450-mi (725-km) strip along the

Pacific Ocean from central California to southern Oregon.

The giant sequoia (Sequoiadendron giganteum) is restricted

to about 75 groves scattered over a 260-mi (418-km) belt,

nowhere more than 15 mi (24 km) wide, extending along

the west slope of the Sierra Nevadas in central California.

The third species, dawn redwood (Metasequoia glyptostro-

boides), was described first from a fossil and was presumed

to be extinct. However, in 1946 live trees were discovered

in a remote region of China. Since then, seeds have been

brought to North America, and this species is now found

in many communities as an ornamental planting. Unlike

the coast redwoods and giant sequoias, dawn redwoods are

deciduous.

Redwoods are named for the color of their heartwood

and bark. The thick bark protects the trees from fires which

occur naturally throughout their ranges. Their wood has a

high tannin content which makes it resistant to

fungi

and

insects, making redwood a particularly desirable building

material. This demand for lumber was responsible for most

of the destruction of the original redwood forests in North

America. In 1918, the

Save-the-Redwoods League

was

formed to save redwoods from destruction and to establish

redwood parks. This organization has purchased and pro-

tected over 280,000 acres (113,400 ha) of redwood forests

and was instrumental in the establishment of the Redwoods

National Park

. The term Sequoia used in the generic names

of these species, and in the common name giant sequoia,

honors the Cherokee Chief Sequoyah who developed an

alphabet for the Cherokee language.

Coast redwoods

Coast redwoods are the tallest and one of the longest

living tree species. Average mature trees are typically 200–

240 ft (61–73 m) tall, although some trees exceed 360 ft

(109 m). The world’s tallest known tree is a coast redwood

that stands 368 ft (112 m) tall on the banks of Redwood

Creak in Redwood National Park. In some areas coast red-

woods can live for more than 2,000 years. They are evergreen,

1182

Coast redwoods. (Photograph by Jack Dermid. Photo

Researchers Inc. Reproduced by permission.)

with delicate foliage consisting of narrow needles 0.5–0.75 in

(1.3–2 cm) long, growing flat along their stems and forming a

feathery spray.

Coast redwoods are prolific. Their cones are about an

inch long and contain from 30 to 100 seeds. They produce

seeds almost every year with maximum seed production oc-

Environmental Encyclopedia 3

Refuse-derived fuels

curring between the ages of 20–250 years old. They also

have an advantage over other species in that new trees can

sprout from the roots of damaged or fallen trees.

Unlike the other two species of redwoods, coastal red-

woods cannot tolerate freezing temperatures. They thrive in

areas below 2,000 ft (607 m), with summer fog, abundant

winter rainfall, and moderate temperatures. Although coast

redwoods are often found in mixed evergreen forest commu-

nities, they can form impressive pure stands, especially on

flat, riparian areas with rich soils.

Giant sequoia

The giant sequoia, although not as tall as the coast

redwood, is a larger and more long-lived species. Giant

sequoias can attain a diameter of 35 ft (10.6 m); whereas

the largest Coast redwood has a 22-ft (6.7-m) diameter.

The largest tree species by volume, giant sequoias the trees

through which roads were built and rangers’ residences hol-

lowed out. The most massive specimen, the General Sher-

man tree, located in Sequoia National Park, has a bole vol-

ume of 52,500 ft

(1,575 m

)

The oldest giant sequoia is 3,600 years old, compared

with 2,200 years old for the oldest coast redwood. This

makes the giant sequoia the second oldest living thing on

earth (the bristlecone pine is the most long-lived).

Giant sequoias can be found between elevations of

5,000 and 8,000 ft (1,517 and 2,427 m), growing best on

mesic sites (such as bottomlands) with deep, well-drained

sandy loam soil. Unlike coast redwoods, mature trees of this

species cannot sprout from the roots, stumps, or trunks of

injured or fallen trees (young trees can produce stump sprouts

subsequent to injury). It is paradoxical that one of the largest

living organisms is produced by one of the smallest seeds.

Three thousand seeds would weigh only an ounce. Typically,

cones bearing fertile seeds are not produced until the tree

is 150–200 years old. The cones are egg-shaped and 2.0–

3.5 in (5–9 cm) in length. Once cones develop they may

continue to grow without releasing the seeds for another 20

years. A typical mature tree may produce 1,500 cones each

year, and because they are not dropped annually, a tree may

have 30,000 cones at one time, each with about 200 seeds.

Two species of animals, a wood-boring beetle (Phymatodes

nitidus) and the chickaree or Douglas squirrel (Tamiasciurus

douglasii), play important roles in dislodging the seed from

the cones. Fire is also important in seed release as the heat

drys the cones. Fire has the added advantage of also preparing

a seed bed favorable for germination. The light seeds are

well-adapted for wind dispersal, often travelling up to a

quarter mile away from the source tree.

Like the other redwoods, the wood of the giant sequoia

is extremely durable. Because of this durability and the ornate

designs in the wood, this species was harvested extensively.

One tree can produce up to 600,000 board feet of lumber,

1183

enough to fill 280 railroad freight cars or build 150 five-

room houses. Unfortunately, because of the enormous size

of the trees and the brittle nature of the wood, when a tree

was felled, as much as half would be wasted because of

splintering and splitting. Now that virtually all giant trees

have been protected from

logging

, the greatest threats from

humans are

soil compaction

around their bases and the

elimination of fire which allows fuels to accumulate, thereby

increasing the chances of deadly crown fires. Toppling over

is the most common natural cause of death for mature giant

sequoia trees. Weakening of the shallow roots and lower

trunk by fire and decay, coupled with the tremendous weight

of the trees, results in the tree falling over. Sometimes wind,

heavy snows, undercutting by streams, or water-soaked soils

contribute to the toppling. In its natural range this species

is now valued primarily for its aesthetic appeal.

[Ted T. Cable]

ESOURCES

OOKS

Burns, R. M., and B. H. Honkala. Silvics of North America. Vol. 1, Conifers.

Washington, DC: U.S. Dept. of Agriculture, 1990.

Dewitt, J. B. California Redwood Parks and Preserves. San Francisco: Save-

the-Redwoods League, 1985.

Walker, L. C. Trees: An Introduction to Trees and Forest Ecology for the

Amateur Naturalist. Englewood Cliffs, NJ: Prentice-Hall, 1984.

Refuse-derived fuels

The concept of refuse-derived fuels (RDFs) is one that has

the potential for addressing two of the most troubling envi-

ronmental problems in the world at the same time:

solid

waste

disposal and a source of energy. The term refuse-

derived fuel refers to any process or method by which waste

materials are converted into a form in which they can be

burned as a source of energy.

In regions of the world characterized by a throw-

away ethic and swamped with essentially non-degradable

materials, accumulation and disposal of solid waste continue

to be a growing problem. In 1960, each American generated

2.7 lb (1.2 kg) of solid waste. This grew to 4.3 lb (1.9 kg)

per person by 1990. Americans continue to generate more

solid waste each day but the rate of growth has decreased.

In 2002, every man, woman, and child in the United States

produced an average of 4.5 lb (2.0 kg) of waste each day.

Materials are labeled wastes because they tend to have

no future use once they are discarded. Yet, by their very

Environmental Encyclopedia 3

Refuse-derived fuels

nature, most solid wastes are potentially valuable as fuels. A

typical sample of municipal waste in the United States, for

instance, may consist of about 30–40% paper, 5% textiles,

5% wood, and 20–30% organic material. All of these materi-

als are combustible. Metals, glass,

plastics

, sand, and other

non-combustible materials constitute the remaining portion

of a waste sample. Each of these non-combustible materials

is potentially recyclable.

Even though 70% or more of municipal wastes appear

to have potential value as sources of fuel, that potential has

not, as yet, been extensively developed. In most countries,

solid wastes are mainly disposed of in landfills. A small

fraction is incinerated or used for other purposes. However,

conversion of solid wastes to a useable fuel is still an experi-

mental process.

The primary roadblock to the commercial develop-

ment of RDFs is the economic cost of preparing such fuels.

Given that most RDFs produced have only about half the

energy value of a typical sample of industrial

coal

and given

the relatively low price of coal, there is little economic incen-

tive for municipalities to build energy systems based on

refuse-derived fuels.

Many scientists, engineers, and environmentalists see

a positive future for refuse-derived fuels. They argue that as

fossil fuel reserves are consumed, the cost of traditional fuels

such as coal, gas, and oil will inevitably increase. In addition,

RDFs tend to burn more cleanly and have a significant

environmental advantage over coal and other

fossil fuels

Research must continue, therefore, to develop more efficient

and less expensive RDFs and associated processes to obtain

and use them.

One of the fundamental problems in the development

of refuse-derived fuels is obtaining the raw materials in a

physical condition that will allow the extraction of combusti-

ble organic matter. The solid waste material entering most

landfills consists of a complex mixture of substances. Some

of these are combustible while others are not. Some have

other commercial values while others have none. Plastics

provide a convenient example that illustrates both of these

aspects.

The first step in preparing wastes for the production

of refuse-derived fuels is known as size reduction. In this

step, waste materials are shredded, chopped, sliced, pulver-

ized, or otherwise treated in order to break them up into

smaller pieces. Most methods for separating combustible

from non-combustible materials require that waste particles

be small in size. Both

magnetic separation

and air classifi-

cation will work only with small particles.

Size reduction also serves a number of other functions.

For example, it breaks open plastic and glass bottles, releasing

any contents that may still be in them. It also reduces clump-

ing and tangling that often occurs with larger particles. Fi-

1184

nally, when used as a fuel, particles of small size burn more

efficiently than larger particles.

One indication of the importance of size reduction in

the production of RDFs is the number of different machines

that have been developed to accomplish this step. Bag break-

ers are used to tear open plastic bags and cardboard boxes.

Machines called chippers reduce cut wood into small pieces.

Granulators have sharp knives on rotating blades. These

devices cut materials against a stationary blade, somewhat

similar to a pair of scissors. Flail mills are rotary machines

that swing hammers around in a circle to smash materials.

Ball and rod mills consist of cylindrical drums that hold

balls or rods. When the drums spin, balls or rods smash

against the inside of the drum, crushing solid wastes also

present in them.

Once waste materials have been reduced in size, the

portion that is combustible must be removed from that which

is not. Several different procedures can be used. A common

process, for example, is to pass the solid wastes under a

magnet. The magnet will extract all metals containing iron

(ferrous) from the mixture.

Another technique is rotary screening, in which wastes

are spun in a drum and sorted using screens that have open-

ings of either 50 mm or 200 mm diameter. Sand, broken

glass, dust, and other non-organic materials that do not burn

tend to be removed by this procedure.

A third process is known as air classification. When

solid wastes are exposed to a blast of air, various components

are separated from each other on the basis of their size,

shape, density, and moisture content. A number of different

kinds of air classifiers exist, and all are reasonably efficient

in separating organic from inorganic materials.

One type of air classifier is the horizontal model, in

which size-reduced wastes are dropped into a horizontal

stream of air. Various types of material are separated on the

basis of the horizontal distance they travel from their point

of origin. Vertical classifiers separate on a similar principle

except that particles are injected into a rising stream of air.

The rotary classifier consists of an inclined cylindrical col-

umn into which wastes are injected and then separated by

a rotating, rising column of air.

The organic matter that remains after size reduction

and separation can be used as a fuel in four distinct ways.

First of all, it can be converted to other combustible forms

through pyrolysis. Pyrolysis is a process in which organic

materials are heated to high temperatures in an oxygen-

free or oxygen-deficient

atmosphere

. The product of this

reaction is a mixture of gaseous, liquid, and solid compounds.

The solid compounds can be used as fuels and are collectively

called char.

Two particularly valuable fuels,

methane

(a gas) and

ethanol

(ethyl alcohol, a liquid), can also be produced from

Environmental Encyclopedia 3

Tom [Thomas Howard] Regan

organic wastes. Scientists have long known that methane is

produced when

anaerobic

bacteria act on organic com-

pounds found in solid wastes. They have successfully ex-

tracted methane from landfills and used it as a fuel. However,

they have achieved only limited success in generating meth-

ane from other refuse outside of landfills.

Some success has been obtained in the production

of ethanol from wastes. This process separates materials

containing cellulose from other wastes and then hydrolyzes

them in an acidic medium. As of 2002, ethanol has not been

generated in commercially useful amounts from solid waste

streams. However, ethanol has been obtained from corn and

some other crop materials. In some states, ethanol is added

gasoline

, producing a fuel that burns more cleanly and

efficiently than pure gasoline.

Some heating systems make use of the dried material

produced as a result of size reduction and separation directly

as a fuel. The Imperial Metal Industries (IMI) company in

Birmingham, England, has operated such a plant since 1976.

Solid wastes provided by the West Midlands County Coun-

cil is delivered to the IMI plant where it is reduced in size,

separated, dried, and then fed directly into furnaces, where

it is burned. A similar plant operated by Commonwealth

Edison and run on wastes from the city of Chicago was

opened in 1978.

A convenient and popular method of handling RDFs

is to process them as pellets or briquettes. Pellets are formed

from wastes that have been size reduced, separated, and

partially dried. The material is extruded through a dye or

compacted into small nuggets in devices known as densifying

machines. An important factor in the success of this method

is keeping the wastes moist enough to stick together, but

dry enough for efficient

combustion

Finally, research has been conducted on the use of

RDFs in combustion systems, such as

fluidized bed com-

bustion

. In this process, fuel is mixed with some material

such as sand and suspended in a furnace by a stream of air.

The second material makes thorough mixing of the fuel

possible. The fuel is then burned in the air stream.

A considerable number of research and engineering

studies have been conducted on refuse-derived fuels. As

of 2002, many municipalities operate plants that generate

electricity. With the help of modest tax benefits in some

but not all areas, most of these facilities are commercially

successful. They have reduced the volume of waste entering

local landfills. In turn, the life of existing landfills has been

extended and the need to open new landfills has been re-

duced. They generate a modest but significant proportion

of electricity for customers in their municipalities.

[L. Fleming Fallon Jr., M.D., Dr.P.H.]

1185

ESOURCES

OOKS

Diane Publishing Test Firing and Emissions Analysis of Densified RDF

Combustion in a Small Power Boiler. Collingdale, PA: Diane Publishing,

1994.

Hasselriis, F. Refuse-derived Fuel Processing. Boston: Butterworth Publish-

ers, 1984.

Porteous, A. Refuse Derived Fuels. London: Applied Science Publishers,

1981.

Vesilind, P. A., J. J. Peirce, and R. Weiner. Environmental Engineering.

2nd ed. Boston: Butterworth Publishers, 1988.

ERIODICALS

Pian, C. C., and K. Yoshikawa. “Development of a High-temperature

Air-blown Gasification System.” Bioresource Technology 3, no. 79 (2001):

231–241.

THER

“Biomass.” Understanding Energy. [cited July 2002]. <http://www.energy.-

org.uk/EFBioMas.htm>.

PSC Analytical Services. [cited July 2002]. <http://www.philipanalytical.-

com/company.htm>.

Ruzic, David. Biomass. 1998 [cited July 2002]. <http://starfire.ne.uiuc.edu/

ne201/course/topics/biomass>.

Tom [Thomas Howard] Regan (1938 – )

American philosopher and animal rights activist

Regan is a well-known figure in the animal liberation move-

ment. His The Case for Animal Rights (1983) is a systematic

and scholarly defense of the controversial claim that animals

have rights that humans are morally obligated to recognize

and respect. Arguing against the views of earlier philosophers

like Rene

Descartes, who claimed that animals are machine-

like and incapable of having mental states such as conscious-

ness or feelings of pleasure or pain, Regan attempts to show

that such a view is misguided, muddled, or incorrect.

Regan was born in Pittsburgh, Pennsylvania. He at-

tended Thiel College and the University of Virginia, where

he earned his doctorate in philosophy. Before publishing

The Case for Animal Rights, Regan also edited Animal Rights

and Human Obligations (1976) and Matters of Life and Death

(1980).

Within the

animal rights

movement, Regan disagrees

with certain philosophical arguments advanced in defense

of animal liberation by, most notably, the nineteenth-century

English philosopher Jeremy Bentham and the twentieth-

century Australian philosopher

Peter Singer

. Both Bentham

and Singer are utilitarians who believe that morality requires

the pleasures of all sentient creatures—human and nonhu-

man alike—be maximized and their pain minimized. From

a utilitarian perspective, most discussions about rights are

unnecessary. Regan disagrees, arguing that sentience—the

ability to feel pleasure and pain—is an inadequate basis on

which to build a case for animal rights and against such

Environmental Encyclopedia 3

Regulatory review

practices as meat-eating, factory farming, fur

trapping

, and

the use of animals in laboratory experiments.

Regan is currently a professor at North Carolina State

University where he set up the National Bioethics Institute

in 1999. He was also the recipient of the 2000 Holladay

Medal. Regan views the case for animal rights as an integral

part of a broader and more inclusive environmental ethic.

He predicts and participates in the coming of a new kind

of revolution—a revolution of gentility and concern—made

not by a self-centered me-generation but by an emerging

thee generation of caring and concerned people from every

political party, religion, and socioeconomic class. Among

the indications of this forthcoming revolution is the growing

popularity of and financial support for the various groups

and organizations that comprise the more broadly based

environmental and animal rights movements.

[Terence Ball]

ESOURCES

OOKS

Regan, Tom. All That Dwell Therein: Essays on Animal Rights and Environ-

mental Ethics. Berkeley: University of California Press, 1982.

———, and Carl Cohen. The Animal Rights Debate. Lanham, MD: Row-

man & Littlefield, 2001.

———. The Case for Animal Rights. Berkeley: University of California

Press, 1983.

———. The Thee Generation: Reflections on the Coming Revolution. Philadel-

phia: Temple University Press, 1991.

Regulatory review

The regulatory review process allows the executive branch

of the United States federal government to ensure that the

regulations drafted by different agencies contribute to the

current administration’s overall goals. Regulatory review is

also carried on at the state level, although the organizational

structure of these councils or commissions varies somewhat

from state to state. In the past the regulatory review process

has emphasized a

cost-benefit analysis

that has tended to

delay or halt the publication of environmental regulations.

This pattern shifted after 1993 to a greater emphasis on

citizen participation in the process of rulemaking.

Executive agencies carry out congressionally enacted

laws by drafting and enforcing regulations. The

Environ-

mental Protection Agency

(EPA) has responsibility for

writing the regulations that implement environmental laws,

like the

Clean Air Act

and the Comprehensive Environmen-

tal Response, Compensation and Liability Act (Superfund).

For example, when the

Resource Conservation and Recov-

ery Act

(RCRA) called for states to protect

groundwater

from

landfill

leachate, the EPA drafted a regulation that

1186

included specifications for the kind of equipment that land-

fills should install to ensure that leachate would not leak.

An emerging concern in regulatory review is the spiral-

ing costs of regulations related to the

environment

. The

price tag on environmental regulation has tripled over the

last quarter century, from about $80 billion in 1977 to more

than $267 billion in 2000. In addition, a recent study of

regulatory review found that federal agencies involved with

environmental regulations received the largest increases in

the federal budget in recent years, the EPA in particular

receiving an increase of over $1 billion for the fiscal year

2002.

Once drafted, before being published for public com-

ment, all regulations are sent for review to the Office of

Information and Regulatory Affairs (OIRA) within the

Of-

fice of Management and Budget

(OMB). OIRA either

approves, rejects, or asks for specific changes in the regula-

tion. If a regulation is approved it can be published on the

Internet or in hard copy for public comment.

This centralization of the regulatory process was ac-

complished by Ronald Reagan’s executive orders 12291 and

12498. Executive Order 12291, issued in 1981, established

a cost-benefit review process. All federal agencies must weigh

costs and benefits for each “major” regulation and submit

these considerations to OIRA. (A “major” regulation costs

more than $100 million or is otherwise deemed major by

OIRA.) Agencies cannot publish proposed or final rules

until OIRA has ensured that the benefits of a regulation

outweigh the costs. Executive Order 12498, issued in 1984,

requires agency heads to predict their regulatory actions for

the following year. All regulations are then compiled into

the Regulatory Program. Compiling this program allows

OIRA to be involved in the early planning stages of all

regulations.

In September 1993, Executive Orders 12291 and

12498 were replaced by President Clinton with Executive

Order 12866 on regulatory planning and review. While Ex-

ecutive Order 12866 left the basic structure of OIRA in

place, including the figure of $100 million as the standard

of a major regulation, the order was intended to harmonize

federal regulations regarding the environment with related

state, local, and tribal regulations and procedures. The order

also allowed for negotiated rulemaking and other consensual

approaches to developing regulations in appropriate situa-

tions. A third important feature of Executive Order 12866

is its emphasis on transparency; that is, federal agencies are

not only required to “provide the public with meaningful

participation in the regulatory process,” but also to allow

time for comments on proposed regulations. To facilitate

citizens’ participation and response, all regulatory informa-

tion is to be provided to the public “in plain, understandable

language.”