Environmental Encyclopedia

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Environmental Encyclopedia 3

Passive solar design

One ppm times 10,000 equals one part per hundred or one

percent. The

nutrient phosphorus

and the contaminant

lead

found in soil are commonly measured in ppm.

Parts per trillion

A means of expressing extremely minute concentrations of

substances in water or air. In the United States, the concen-

tration is the number of units of the substance found in

1x10

units of water or air; an equivalent unit is nanograms

per kilogram. Detection of concentrations this low, which

was not possible until the late twentieth century, is limited

to only a few types of chemical compounds. For example,

one gram of sulfur hexafluoride, used as a tracer in studies

of ocean mixing, can be detected in a cubic kilometer of sea

water, a concentration of 1,000 parts per trillion.

Passenger pigeon

The passenger pigeon (Ectopistes migratorius), perhaps the

world’s most abundant bird

species

at one time, became

extinct due directly to human activity. In the mid-1800s

passenger pigeons travelled in flocks of astounding numbers.

Alexander Wilson, the father of American ornithology,

noted a flock he estimated to contain two billion birds. The

artist and naturalist John James Audubon once observed a

flock over a three-day period and estimated the birds were

flying overhead at a rate of 300 million per hour.

The species became extinct within a span of 50 years,

several factors having led to its rapid demise. The passenger

pigeon was considered an agricultural

pest

, thus providing

ample reason to kill large numbers of the birds. It was also

in demand as food, largely due to the fact that nesting

flocks were easily accessible. Young squabs were easy prey

for hunters who knocked them from their nests or forced

them out by setting fires below them. Adults were also killed

in huge numbers. They were baited with alcohol-soaked

grain or with captive pigeons set up as decoys, then trapped

and shot. A common practice of the day was to use the

live pigeons as targets in shooting galleries. In 1878, near

Petoskey, Michigan, a professional market hunter earned

$60,000 by killing over three million passenger pigeons near

their nesting grounds. Once killed, many of the birds were

packed in barrels and shipped to cities where they were sold

in markets and restaurants. The demand was particularly

high on the East Coast where forest clearing and

hunting

had already eradicated the species from the area.

By the 1880s commercial hunting of passenger pigeons

was no longer profitable, because the population had been

depleted to only several thousand birds. Michigan provided

their last stronghold, but that population became extinct in

1057

Passenger pigeon. (Photograph by John D. Cunning-

ham. Visuals Unlimited. Reproduced by permission.)

1889. The remaining small flocks of birds were so spread

out and isolated that their numbers were too low to be

maintained. The disruption of the population in the 1860s

and 1870s had been so severe that breeding success was

permanently reduced. At one time the sheer numbers of

passenger pigeons in a flock was enough to discourage poten-

tial predators. Once the population was split into small,

isolated remnants, however, natural predation also contrib-

uted to the species’ rapid decline.

The last individual passenger pigeon was a female

named Martha, which died in the Cincinnati Zoo in 1914.

It is now on display at the National Museum of Natural

History in Washington, D.C.

[Eugene C. Beckham]

ESOURCES

OOKS

Schorger, A. W. Passenger Pigeon: Its Natural History and Extinction. Nor-

man, OK: University of Oklahoma Press, 1973.

ERIODICALS

Wilcove, D. “In Memory of Martha and Her Kind.” Audubon 91 (September

1989): 52–55.

Worsnop, R. L. “Evolving Attitudes.” CQ Researcher 2 (January 24, 1992):

58–60.

Passive solar design

Looking into the sky on a sunny day, the notion that humans

could have an “energy crisis” seems absurd. Each day, the

earth receives 1.78 x 10

kilowatts of energy, more than

10,000 times the amount needed by the whole world this

year. All that is required is a way to collect and harness the

energy of sunlight.

Environmental Encyclopedia 3

John Arthur Passmore

Humans have explored systems for the capture of

solar

energy

for centuries. The Roman architect Vitruvius de-

scribed a plan in the first century

B.C.

for building a bathhouse

heated by sunlight. He explained that the building should

“look toward the winter sunset” because that would make

the bathhouse warmer in the late afternoon. More recently,

water heaters operated by solar energy were built and widely

sold in the early 1990s, especially in California and Florida.

Most historical examples illustrate the principles of

passive solar heating, namely constructing a building so that

it can take advantage of normal sunlight without the use of

elaborate or expensive accessory equipment. A home built

on this principle, for example, has as much window space

as possible facing toward the south, with few or no windows

on other sides of the house. Sunlight enters the south-facing

window and is converted to heat, which is then trapped

inside the house. To reduce loss of heat produced in this

way, the window panes are double- or triple-glazed, that is,

consist of two or three panes separated by air pockets. The

rest of the house is also as thoroughly insulated as possible.

In some cases, a house can be built directly into a south-

facing hill so that the earth itself acts as insulation for the

north-, east-, and west-facing walls.

Adjustments can also be made to take account of

changing sun angles throughout the year. In the winter,

when the sun is low in the sky, solar heat is needed most.

In the summer, when the sun is high in the sky, heating is

less important. An overhang of some kind over the south-

facing window can provide the correct amount of sunlight

at various times of the year. Changing seasonal temperatures

can also be managed by installing insulating screens on the

south-facing window. When the screens are open, they allow

solar energy to come in. When they are closed (as at night),

they keep heat inside the building.

The primary drawback to the use of solar energy is its

variability. Often the energy supply and the energy require-

ments are out of balance for weeks or months depending

on season, amount of cloud cover, latitude, etc. Thus, there

is frequently the need for storage of energy for later use.

Several technologically-simple methods for storing solar en-

ergy are commonly used in passive solar design. A large

water tank on top of the house, for example, provides one

way to store this energy. Sunlight warms the water during

the day and the water can then be pumped into the house

at night as a heat source. A heat sink such as a dark-colored

masonry wall or concrete floor near the south facing windows

can also enhance a passive solar system by absorbing heat

during the day and slowly radiating it into the room during

the night. A Trombe wall may also be installed. This ma-

sonry wall, 6-18 inches (15-46 cm) thick with gaps at the

top and bottom, faces the sun. The space in front of the

wall is enclosed by glass. Air between the glass and the

1058

masonry wall is heated by the sun, rises and passes into the

room behind the wall through the upper gap. Cooler air is

drawn from the room into the space through the lower gap.

The masonry wall also acts as a heat sink.

[David E. Newton]

ESOURCES

OOKS

Anderson, B. Passive Solar Energy: The Homeowner’s Guide to Natural

Heating and Cooling. Amherst, MA: Brick House Publishing, 1993.

Balcomb, J. D. Passive Solar Buildings. Cambridge: MIT Press, 1992.

Mazria, E. The Passive Solar Energy Book: A Complete Guide to Passive Solar

Home, Greenhouse, and Building Design. Emmaus, PA: Rodale Press, 1979.

John Arthur Passmore (1914 – )

Australian philosopher and writer

As a philosopher, John Passmore has defended Western

civilization against the charge that such societies “can solve

their ecological problems only if they abandon the analytical,

critical approach which has been their peculiar glory and go

in search of a new ethics, a new metaphysics, a new religion.”

We do indeed face daunting ecological crises, Passmore

states, but the best hope for solving them lies in “a more

general adherence to a perfectly familiar ethic.”

Born in Manly, New South Wales,

Australia

,on

September 9, 1914, Passmore earned his B.A. and M.A.

degrees from the University of Sydney, where he taught

philosophy from 1935 to 1949. He then served on the facul-

ties of Otago University in New Zealand and the Australian

National University, holding the chair of philosophy at the

latter from 1959 to 1979. The best known of his many

publications are Hume’s Intentions (1952), A Hundred Years

of Philosophy (1957), The Perfectibility of Man (1970), and

Man’s Responsibility for Nature (1974).

Part of Passmore’s argument in Man’s Responsibility

for Nature is that people in the West, like people everywhere,

cannot simply adopt a new and unfamiliar way of thinking:

one must begin where one is at. He also insists that Western

civilization encompasses more than one way of thinking.

He argues that “central Stoic-Christian traditions are not

favourable to the solution of [the West’s] ecological prob-

lems...” but that these “are not the only Western traditions

and their influence is steadily declining.” More favorable are

traditions such as Jewish thought and, especially, modern

science. These are hospitable to two attitudes—a sense of

stewardship and a sense of cooperation with nature—that

are incompatible with the Stoic-Christian traditions, “which

deny that man’s relationships with

nature

are governed by

any moral principles and assign to nature the very minimum

of independent life.”

Environmental Encyclopedia 3

Pathogen

As a champion of stewardship and cooperation with

nature, Passmore sharply disagrees with those who see civili-

zation as an enemy of nature or a blight upon it. On the

contrary, Passmore sees in civilization “man’s great memori-

als—his science, his philosophy, his technology, his architec-

ture, his countryside...all of them founded upon his attempt

to understand and subdue nature.” He considers the transfor-

mation of the natural

environment

necessary and, when

done with care, desirable. For there is “no good ground...for

objecting to transforming as such; it can make the world

more fruitful, more diversified, and more beautiful.”

Passmore’s case for a more responsible attitude toward

nature rests, finally, on a rejection of mysticism that includes

a rejection of religion and the concept of the sacred: “To

take our ecological crises seriously...is to recognize, first,

man’s utter dependence on nature, but secondly, nature’s

vulnerability to human depredations—the fragility, that is,

of both man and nature, for all their notable powers of

recuperation. And this means that neither man nor nature

is sacred or quasi-divine.”

[Richard K. Dagger]

ESOURCES

OOKS

Evory, A., ed. Contemporary Authors: New Revision Series 6. Detroit: Gale

Research Co., 1982.

Passmore, J. Hume’s Intentions. 3rd ed. London: Duckworth, 1980.

———. A Hundred Years of Philosophy. Rev. ed. New York: Basic

Books, 1966.

———. Man’s Responsibility for Nature: Ecological Problems and Western

Traditions. London: Duckworth, 1974.

———. The Perfectibility of Man. New York: Scribner Sons, 1970.

Pathogen

A pathogen is an agent that causes disease. Pathology is the

scientific study of human disease. One could argue that

anything that causes disease is therefore by definition a

“pathogen.” Sunlight is the environmental agent that (with

excessive exposure) induces the potentially fatal skin

cancer

known as melanoma. Ordinarily, however, most people do

not consider sunlight to be a pathogen. An unbalanced diet

may result in nutritional deficiencies which can lead to dis-

eases such as pellagra (caused by a niacin deficiency) and

scurvy (caused by inadequate vitamin C in the diet). Never-

theless, the failure to consume a balanced diet is not consid-

ered to be a pathogen. Generally, most students of disease

refer to biological agents when they use the term pathogen.

Such agents, which include viruses, bacteria,

fungi

, protozoa,

and worms, cause a tremendous diversity of diseases.

1059

Viruses, while considered biological agents, are not

cellular organisms and accordingly, are not living in the usual

sense. They are tiny particles consisting of either DNA or

RNA as the genetic material and a protein coat, and they are

incapable of

metabolism

outside of a living cell. Pathogenic

viruses cause diseases of the respiratory system such as colds,

laryngitis, croup, and influenza. Skin eruptions such as mea-

sles, rubella, chicken pox, and foot-and-mouth disease are

viral in origin. The long list of viral diseases include insect-

borne Western equine encephalitis and yellow fever. Re-

cently, some human cancers have been thought to be associ-

ated with viruses, perhaps because animal cancers such as

the Lucke

renal carcinoma and mouse mammary carcinoma

are known to be caused by viruses. One such human cancer

is Burkitt’s lymphoma, a childhood malignancy occurring

primarily in Africa, which is associated with a herpes

virus

AIDS

results from infection with HIV and is a pandemic

viral disease.

Bacteria are true cells but their genetic material, DNA,

is not packaged in a nucleus as in all higher forms of life. Not

all bacteria are pathogens, but many well-known diseases

are caused by bacterial infections. Tuberculosis,

cholera

plague

, gonorrhea, syphilis, rheumatic fever, typhus, and

typhoid fever are some of the very serious diseases caused

by pathogenic bacteria.

Probably 100 million cases of

malaria

occur each year

primarily in Africa, Asia, and Central and South America.

Malaria is caused by four

species

of the protozoan Plasmo-

dium. Amebiasis and giardiasis are parasitic protozoa infec-

tions. Protozoa are single-celled animals. Thrush (candidia-

sis) is a common infection of mucous membranes with a

yeast-like fungus. Valley fever (coccidioidomycosis) is a fungal

infection generally limited to the lungs. Athlete’s foot is a

common skin infection caused by a fungus.

Worms that infect humans are a significant health

problem in those parts of the world where there is inadequate

public health protection. Examples of helminth infections

are the beef and pork tapeworms. The consumption of inade-

quately cooked pork can result in trichinosis, which is a

roundworm (nematode) infection of human muscle. Trema-

tode flukes cause an extraordinarily important infection in

Asia and Africa called

schistosomiasis

with hundreds of

millions of individuals infected. Perhaps the most common

parasitic helminth infection in the United States is enterobia-

sis known as pinworm or seatworm infection, which is a

common condition of children with improper personal hy-

giene.

Many diseases caused by

microbial pathogens

can

be treated with a diversity of antibiotics and other drugs.

However, viral pathogens remain intractably difficult to

manage with drugs.

[Robert G. McKinnell]

Environmental Encyclopedia 3

Ruth Patrick

Ruth Patrick (1907 – )

American biologist and limnologist

Emphasizing the vital importance of environmental clean-

up and

conservation

, Ruth Patrick has spent a lifetime

facilitating cooperation among the scientific and political

communities to find solutions to biospheric

pollution

. Her

aggressive endeavors in freshwater research, including work

on diatoms and the biodynamic cycles of rivers, have made

much progress toward rectifying damage done by pollutants.

Her enthusiasm and concern for the

biosphere

began

at an early age in her hometown of Kansas City, where,

as a child, she conducted many expeditions through the

countryside surrounding her family home. Collecting speci-

men materials and identifying them set the course for Pat-

rick’s future. She was fascinated by the microscopic world

that could be found even in the smallest drop of water.

Patrick continued to foster her interests in science as

she grew older. She attended Coker College in Hartsville,

South Carolina, and earned a bachelor’s degree in botany

there in 1929. She then attended the University of Virginia

where she earned a doctoral degree in 1934. Throughout

her career, Patrick has been awarded honorary degrees from

many institutions, including Princeton University and Wake

Forest University. In 1975, she received the prestigious John

and Alice Tyler Ecology Award (through Pepperdine Uni-

versity); the award amount of $150,000 is the largest amount

granted for a scientific award.

Patrick was a key force in the founding of

limnology

the scientific study of the biological, physical, and chemical

conditions of freshwater. By conducting further studies, she

also became widely known as an expert on diatoms, the

basic food substance of freshwater organisms, and she later

developed the diatometer. The diatometer is used to measure

the levels of diatoms in freshwater, a measurement which

is used in evaluating the pollution levels and general health

of freshwater bodies. During the late 1960s and early 1970s,

she acted as a consultant in both the private sector and in

government, and her vast knowledge and influence enabled

her to play an active role in the development of

environmen-

tal policy

. She worked with the

U.S. Department of the

Interior

and served on numerous committees, including the

Hazardous Waste

Advisory Committee of the

Environ-

mental Protection Agency

(EPA) and the Science Advisory

Council of the World

Wildlife

Federation. She has often

been called the “Ralph Nader of water pollution,” and she

has a wide reputation as a dauntless watchdog. Patrick has

conducted most of her work through her offices at the Acad-

emy of Natural Sciences in Philadelphia, where she has been

on staff since the late 1930s. She was the first female board

chairperson at the academy.

1060

Patrick also maintains membership in such organiza-

tions as the

National Academy of Sciences

, the National

Academy of Engineering, the American Academy of Arts

and Sciences, the International Limnological Society, the

American Society of Limnology and Oceanography, and the

American Society of Naturalists. She has been bestowed

dozens of awards from schools, institutions, and organiza-

tions, and she has written four books, including Diatoms of

the United States (with C. W. Reimer). In 1996, Patrick was

presented with a National Medal of Science by President

Clinton for her work in pioneering the field of limnology

and inducted into the South Carolina Hall of Science and

Technology. In 1999, she was awarded the Governor of

South Carolina, and currently hold the Francis Boyer Chair

of Limnology and Senior Curator at the National Academy

of Sciences.

[Kimberley A. Peterson]

ESOURCES

OOKS

Patrick, Ruth. Diatoms of the United States, Exclusive of Alaska and Hawaii.

Philadelphia: University of Pennsylvania Press, 1966.

———. Groundwater Contamination in the United States. Philadelphia:

University of Pennsylvania Press, 1987.

———. Surface Water Quality: Have the Laws Been Successful? Princeton,

NJ: Princeton University Press, 1992.

ERIODICALS

Kunreuther, H., and Ruth Patrick. “Managing the Risks of Hazardous

Waste.” Environment 33 (April 1991): 12–21.

PBBs

see

Polybrominated biphenyls

PCBs

see

Polychlorinated biphenyls

PCP

see

Pentachlorophenol

Peat soils

soil

that is derived completely from the decomposing

remains of plants. Plants that commonly form peat include

reeds, sedges, sphagnum moss, and grasses. The plant re-

mains do not decompose but continue to accumulate because

the wet and/or cool

environment

in which they occur is

not conducive to

aerobic decomposition

. Vegetable crops

are often grown on peat soils. Peat can also be harvested for

Environmental Encyclopedia 3

People for the Ethical Treatment of Animals

use in horticulture or as a fuel for heating and cooking. See

also Peatlands

Peatlands

Expansive areas of

peat soils

are referred to as peatlands.

These areas are often located in what were once lakes or

oceans. The clay deposits from the former lake provide an

impermeable layer so that water accumulates. Plants growing

in this wet

environment

will not be able to decompose

because of a lack of oxygen. Accumulations of plants will

continue to increase the thickness of the peat deposit until

soil

formed entirely of peat is created. These deposits can

be 40 feet (12 m) or more thick. Extensive peatlands occur

in Minnesota, Wisconsin, Michigan, New England, Russia,

England, and Scandinavian countries.

Pedology

The scientific study of

soil

as a natural body, without empha-

sizing the practical uses or ecological significance of the soil.

Pedology includes soil formation and morphology, its basic

physical and chemical properties, its distribution, and the

erosional processes affecting it without direct regard to plants

or animals. Pedology provides the foundation for the study

of soil as a medium of biological activity, called

edaphology

and for the study of soil necessary in construction and

drain-

age

projects.

Pelagic zone

The entire water column in marine ecosystems, regardless

of depth. Plants and algae in the pelagic zone directly or

indirectly support most of the ocean’s animal life. Because

plant growth is confined to the shallow depths of the pelagic

zone reached by light (epipelagic zone, 0-650 ft/0-200 m),

much of the biological activity in the pelagic zone is concen-

trated in near-surface waters. The pelagic zone is further

subdivided by depth into the mesopelagic zone (650-3,280

ft/200-1000 m), bathypelagic zone (3,280-13,125 ft/1000-

4000 m) and abyssopelagic zone (greater than 13,125 ft/

4000 m), each zone inhabited by a distinctive

fauna

. These

deeper fauna are nourished largely by organic matter (e.g.

dead

plankton

, fecal material) settling from surface waters.

See also Littoral zone; Neritic zone; Photic zone; Phytoplank-

ton; Zooplankton

Pelecanus occidentalis

see

Brown pelican

1061

Pelican

see

Brown pelican

Pentachlorophenol

One of the most widely manufactured

chemicals

in the

world, PCP is used extensively as a wood preservative for

telephone poles, fences, and indoor or outdoor construction

materials. It has also been used for slime control in the pulp

and paper manufacturing process, for weed control, termite

control, and as a paint preservative. Technical grade PCP

contains trace amounts of less-chlorinated phenols and cer-

tain chlorinated dioxins and

furans

. Concerns over its toxic-

ity have curtailed the use of PCP in the United States to

treat materials that humans or animals will have contact

with. Readily absorbed through skin and also volatile, it is

acutely toxic from dermal exposure or inhalation.

People for the Ethical Treatment of

Animals

Founded in 1980 by Alex Pacheco and Ingrid Newkirk,

People for the Ethical Treatment of Animals (PETA) is a

nonprofit charitable organization dedicated to protecting

and promoting

animal rights

. These rights are not, of

course, civil or religious, but rather, the right to live free

from human-caused pain or predation. To this end, PETA

has mounted campaigns against the use of animals in painful

and frequently fatal medical experiments, as well as in the

testing of cosmetics and other products. They have also

campaigned against the

trapping

of fur-bearing animals, so-

called “factory farming,” such as confining cattle in crowded

feedlots

, and the cruel use of animals in rodeos, carnivals,

and circuses. Through its newsletter, PETA News, and its

“Factsheets,” PETA publicizes these and other abuses and

encourages readers to take action. Members write to the

offending organizations, organize boycotts of their products

or services, and contact their political representatives in sup-

port of proposed or pending legislation regarding the treat-

ment of animals.

Drawing many of its ideas and much of its inspiration

from philosophers such as

Tom Regan

and

Peter Singer

PETA is attempting (in Singer’s words) to “expand the

circle” of creatures considered worthy of respect and protec-

tion. Although other forms of discrimination, such as racism

and sexism, have been widely discredited (if not yet elimi-

nated), another form of discrimination has barely begun to

be recognized.

Speciesism

is the view that one particular

species

, Homo sapiens, is superior to all other species and

that therefore humans have the unquestionable and unlim-

Environmental Encyclopedia 3

Peptides

About 50 members of People for the Ethical Treatment of Animals (PETA) and several dogs protest against a

furrier in Atlanta, Georgia. The protestors wore red shirts to symbolize the blood spilled to make fur garments.

(Corbis-Bettmann. Reproduced by permission.)

ited right to use or to kill those other species for food, fur,

leather, labor, or amusement. Such speciesist beliefs and

attitudes are deeply rooted in our culture, Regan and Singer

argue, and challenging them is often very difficult.

Animal rights advocates have been accused of putting

the interests of animals above or at least on a par with

those of human beings. Many critics of PETA quote, out

of context, Ingrid Newkirk’s statement that “a rat is a pig

is a dog is a boy,” thereby purporting to prove that PETA

and other animal rights organizations equate the rights and

interests of human and nonhuman animals. This statement

of Newkirk’s was actually intended to show that humans,

like animals, are sentient beings because they have a central

nervous system and are therefore able to feel pleasure and

pain. “When it comes to having a central nervous system

and the ability to feel pain, hunger, and thirst,” said Newkirk,

“a rat is a pig is a dog is a boy.” More elaborate and extended

versions of the argument about sentience can be found in

Peter Singer’s Animal Liberation (1990) and in Tom Regan’s

The Case for Animal Rights (1983). But PETA’s primary

1062

aim is not to engage in philosophical disputation but to

participate in political, economic, and educational campaigns

on behalf of creatures who cannot defend themselves against

humanly caused pain and predation.

[Terence Ball]

ESOURCES

RGANIZATIONS

PETA, 501 Front St., Norfolk, VA USA 23510 (757) 622-PETA, Fax:

(757) 622-0457, Email: info@peta-online.org, <http://www.peta-

online.org>

Peptides

A chemical compound consisting of two or more amino

acids joined to each other through a bond between the

nitrogen

atom of one amino

acid

to an oxygen atom of its

neighbor. A more precise term describes the number of

amino acid units involved. A dipeptide or tripeptide consists

Environmental Encyclopedia 3

Peregrine falcon

Peregrine falcons on ledge, downtown Detroit, Michigan. (Photograph by Karl W. Kenyon. National Audubon Society

Collection. Photo Researchers Inc. Reproduced by permission.)

of two or three amino acid units respectively. A few oligopep-

tides (about ten amino acid units) are of physiological impor-

tance. The antibiotics bacitracin, gramicidin S, and tyrocidin

A are examples of oligopeptides. The largest polypeptides

contain dozens or hundreds of amino acid units and are

better known as proteins. The bond between peptide units

is especially sensitive to attack by various types of corrosive

poisons such as strong acids and bases.

Percina tanasi

see

Snail darter

Percolation

The movement of water through

soil

and the unsaturated

zone into and through the pores of materials in the

zone

of saturation

Groundwater

is recharged by this move-

ment of water through the unsaturated zone. From a soil

science perspective, percolation refers to the

drainage

initially wetted areas of soil and movement of water beyond

1063

the rooting zone of plants toward the

water table

. Sanitari-

ans commonly use percolation, however, in reference to re-

sults of the common soil test, known as the Perk test, which

evaluates the rate at which soils accept water. The rate water

moves into the soil is referred to as percolation. See also

Aquifer; Aquifer restoration; Drinking water supply; Re-

charge zone; Vadose zone; Water table draw-down

Peregrine falcon

The peregrine falcon (Falco peregrinus), a bird of prey in the

family Falconidae, is one of the most wide-ranging birds in

the world with populations in both the Eastern and Western

Hemispheres. However, with extensive

pesticide

use, par-

ticularly DDT, beginning in the 1940s, many populations

of these birds were decimated. In the United States by the

1960s, the peregrine falcon was completely extirpated from

the eastern half of the country because DDT and related

compounds, which are amplified in the

food chain/web

Environmental Encyclopedia 3

Perfluorooctane sulfonate

caused the birds’ eggshells to become thin and fragile. This

led to reproductive failures, as eggs were crushed in the nest

during incubation. Prior to the DDT-induced losses, there

were about 400 breeding pairs of peregrine falcons in the

eastern United States. In the early 1970s there were over

300 active nests in the western states, but within a single

decade that number dropped to 200. The numbers continued

to decline, and in 1978 there were no breeding pairs of

peregrine falcons in the eastern United States. By 1984, due

to reintroduction efforts, there were 27 nesting pairs, and

in 1985, 38 nesting pairs were present in the east with at

least 16 pairs fledging young. Also in 1985, 260 young,

captive-raised peregrine falcons were released into the wild,

125 in the eastern states, and 135 in the west. By 1986, 43

pairs were nesting, and 25 of those pairs fledged 53 young.

By 1991, over 100 breeding pairs were found in the east,

and 400 pairs were found in the west. The increase of pere-

grine falcons has brought the numbers up to 215 breeding

pairs in the mid-west regions.

The recovery success of the peregrine falcon is due

largely to the efforts of two groups, the Peregrine Fund

based at Cornell University in Ithaca, New York, and

the

Canadian Wildlife Service

at Camp Wainwright in

Alberta. Much of their research centered on captive breed-

ing for release in the wild and finding ways to induce

the falcons to nest and raise young in their former range.

With great patience, and limited early success, the projects

paid off.

The restoration projects also yielded much valuable

information as well as innovative approaches to reestablish-

ing peregrine falcon populations. For captive breeding, fal-

cons trapped as nestlings stood a much better chance of

reproducing in captivity than when trapped as flying imma-

tures or adults. Since

habitat

destruction and human en-

croachment limit potential nesting sites—which typically are

cliff ledges—researchers found that a potential, and ulti-

mately successful, alternative nest site was the window ledge

of tall, city buildings. These locations mimic their natural

nest sites, and these “duck hawks,” as they were once called,

had a readily available prey in their new urban

ecosystem

Peregrine falcons immediately began killing rock doves for

food, which some saw as a service to the cities, since these

“pigeons” tended to be regarded as a “nuisance”

species

Since it began in the 1970s, this captive breeding and

release program has become well established, with over 4,000

captive-bred peregrine falcons released over the past three

decades. In August of 1999, the peregrine falcon was re-

moved from the

Endangered Species

list by the U.S.

Fish

and Wildlife Service

[Eugene C. Beckham]

1064

ESOURCES

OOKS

Ehrlich, P., D. Dobkin, and D. Wheye. Birds in Jeopardy. Stanford, CA:

Stanford University Press, 1992.

Ratcliffe, D. A. The Peregrine Falcon. Vermillion, SD: Buteo Books, 1980.

THER

The Peregrine Fund. [cited May 2002]. <http://peregrinefund.org>.

The Raptor Center. [cited May 2002]. <http://www.raptor.cvm.umn.edu>.

Perfluorooctane sulfonate

Fluoro-organic

chemicals

such as perfluoro-octane sulfo-

nate (C

H)(PFOS), have been used since the 1950s

in soil- and stain-resistant coatings for fabrics, carpets, and

leather (2.4 million lb [1 millionkg] in 2000), as well as in

oil- and grease-resistant coatings for paper products (about

2.7 million lb [1.2 million kg]in 2000). Though PFOS is

mostly applied to products in textile mills, leather tanneries,

finishers, and carpet manufacturing facilities, the use of

Scotchgard fabric protector also allows for the use of PFOS

by the consumer. Additional uses of PFOS and related com-

pounds in specialized industrial applications (1.5 millions lb

[680,000 kg] in 2000) include fire-fighting foams, mining

and oil well surfactants,

acid

mist suppressants for metal

plating and electronic etching baths, alkaline cleaners, floor

polishes, photographic film, denture cleaners, and shampoos,

and ant insecti cide.

In May 2000, 3M Corporation announced that, by

2002, it would phase out a group of perfluorinated chemicals,

including PFOS, used in Scotchgard and other products.

3M Corporation is the only manufacturer of PFOS in the

United States. All of the fluorochemicals that are being

phased out either use PFOS in their manufacture or break-

down to PFOS, which is persistent in the

environment

due to the high energy of the carbon-fluorine bond. 3M

Corporation had conducted a major research effort to charac-

terize the environmental presence, environmental and hu-

man effects, and environmental fate of PFOS; the results

of those research efforts indicated that continued use of

PFOS could potentially have severe long-term consequences

to human health and the environment.

PFOS, unlike most other persistent organic com-

pounds, does not accumulate in fats, but as a surfactant with

both lipophilic and hydrophobic tendencies, binds to blood

proteins and accumulates in the liver and gall bladder. In a

study published in 2001, PFOS was shown to be present in

each of 65 human blood samples from persons who had not

been industrially exposed to PFOS. In another 2001 study,

247 tissue samples from marine mammals collected from

Environmental Encyclopedia 3

Permaculture

Florida, California, and Alaskan coastal waters, as well as

the northern Baltic Sea, the Arctic, and Sable Island in

Canada were analyzed for PFOS. PFOS was found in the

blood and livers of nearly all of the marine mammals. Al-

though animals from sites nearer to developed and industri-

alized regions had higher levels of PFOS in their tissues,

animals from even the most remote locations, including the

Arctic Ocean, were found to have contain significant levels

of PFOS. Near-shore animals had higher concentrations

those that lived off shore. Further, fresh-water

species

had

higher concentrations than ocean species. PFOS was also

found in samples of 21 species of fish-eating birds, including

eagles, ospreys, albatrosses, gulls, herons, loons, ibises, and

gannets that had been collected from locations in the United

States and the central Pacific Ocean. Birds in more urbanized

areas had higher concentrations. Birds from the central Pa-

cific also had measurable PFOS levels, indicating the pres-

ence of PFOS in remote marine locations. The lowest con-

centrations of PFOS were found in an insect-eating gull.

Contamination levels observed in these studies were lower

than those known to be toxic in

wildlife

; however, additional

studies are required to determine the long-term effects of

low-level exposure to PFOS.

Toxicological studies have shown that PFOS can result

in adverse developmental, reproductive, and

systemic

ef-

fects. In a study of two generations of rats and the effects of

PFOS on reproduction, PFOS was found to cause postnatal

death as well as have detrimental developmental effects. At

the highest doses (3.2 mg/kg/day), the offspring in the first

generation of rats died, while at one-half of the highest dose

(1.6 mg/kg/day), almost one-third of the offspring in the

first generation died. At a lower dose (0.4 mg/kg/day), PFOS

resulted in lower pup weight compared to controls. Revers-

ible delays in reflex and physical development were also

observed in this study.(

In Rhesus monkey studies, no monkeys survived

more than three weeks at 10 mg/kg/day or more than

seven weeks at doses of 4.5 mg/kg/day. Cynomolgus

monkeys also died at a dose of 0.75 mg.kg.day, after first

becoming listless and exhibiting loss of appetite. Both

species of monkeys showed liver enlargement and reduced

cholesterol levels in the blood.

From the results of the toxicological studies and the

survey of animals and human blood samples throughout the

world, a representative of the U.S.

Environmental Protec-

tion Agency

(EPA) stated that PFOS exhibits “persistence,

bioaccumulation

, and toxicity to an extraordinary degree".

Research is being conducted to develop safer substitutes for

PFOS.

[Judith L. Sims]

1065

ESOURCES

ERIODICALS

Giesy, J. P., and K. Kannan.Global Distribution of Perfluorooctane Sulfonate

in Wildlife.Environmental Science and Technology 35(2001): 1339–1342.

Kannan, Kurunthachalam, et al. “Accumulation of Perfluorooctane Sulfo-

nate in Marine Mammals.”Environmental Science and Technology35 (2001):

1593–1598.

Kannan, Kurunthachalam, et al. “Perfluorooctane Sulfonate in Fish-eating

Water Birds Including Bald Eagles and Albatrosses.” Environmental Science

and Technology35 (2001): 3065–3070.

Renner, Rebecca. “Growing Concern Over Perfluorinated Chemicals.” En-

vironmental Science and Technology 35 (2001): 154A–160A.

Permaculture

Permaculture is an approach to land management that cre-

ates high-yielding, low-energy, self-perpetuating systems by

which the functions of animals, plants, humans, and Earth

are integrated to maximize their value and create sustainable

human habitats. Permaculture brings together disciplines

relating to food, shelter, energy, water,

waste manage-

ment

, economics, and social sciences. It aims to maximize

a site’s productivity, while maintaining ecosystems and re-

storing damaged land to a healthy, life-promoting state. Bill

Mollison has written five books on this topic: Introduction

to Permaculture, Permaculture: A Designer’s Manual; Perma-

culture One; Permaculture Two; and Permaculture: A Practical

Guide for a Sustainable Future. Several permaculture organi-

zations and model projects exist around the world.

The term was first coined in 1972 by Bill Mollison

of Tasmania,

Australia

, by merging the terms, “permanent”

and “agriculture.” Although originally developed for small

subsistence farms, the practice has expanded to apply to

gardens and urban settings. Some consider it a lifestyle as

much as a design approach.

Permaculture principles focus on designs for small-

scale intensive systems that are labor-efficient and use bio-

logical resources instead of

fossil fuels

. These designs stress

ecological connections and closed energy and material loops.

The core of permaculture is integrating working relation-

ships and connections between all things. Each component

in a system performs multiple functions, and each function

is supported by many elements. Key to efficient permaculture

design is observing and replicating natural ecosystems. De-

signers maximize diversity with polycultures, stress efficient

energy planning for houses and settlements, and use and

accelerate natural plant

succession

. The philosophy behind

permaculture is one of working with rather than against

nature

, looking at systems in all of their functions, and

using systems for multiple purposes. It is a method of agricul-

ture that aims to endure without constant human inputs and

does not deplete the land.

Environmental Encyclopedia 3

Permaculture

According to Mollison, permaculture has several dis-

tinct characteristics. It makes the most of small landscapes,

using intensive practices. Ideally, nothing is wasted, and

everything is arranged so that the least amount of effort is

exerted and the highest yield from the systems is gained.

Systems are designed that use and complement the natural

systems that are present. For example, storm water is con-

trolled with planted swales (marshy depressions), not con-

crete drains. The design harvests the natural flows of energy

through the landscape (such as sunlight, rain, and plant and

animal behaviors). Diversity is promoted in plant

species

varieties, yield,

microclimate

, and

habitat

. Permaculture

maintains that, in a

monoculture

, a single species cannot

make full use of all of the available energy and nutrients.

Wild or seldom-selected animal and plant species are used.

Each element performs many functions in the system. For

example, a fruit tree provides not only a crop, but also wind

shelter, a trellis,

soil

conditioning, and shade and roosting

for birds. The long-term evolution of the land is recognized,

and those changes are incorporated in planning. All activities

involving the land—agriculture, animal husbandry, extant

forest management

, animal cropping, and landform engi-

neering—are integrated. Difficult landscapes (rocky, marshy,

marginal, or steep) not typically suited to other systems are

utilized. Permaculture involves long-term and evolving land-

use planning, using diverse

flora

and

fauna

in various ways

at different times, recognizing that different species use dif-

ferent nutrients and resources.

Permaculture systems typically feature: passive energy

systems and minimal external energy needs; on site

climate

control; planned future developments; on-site provision for

food self-sufficiency; safe on-site disposal of wastes; low-

maintenance structures and grounds; assured and conserved

water supply; and control and direction of fire, cold, excess

heat, and wind factors.

Permaculture originated as a strategy for designing

systems for “permanent” or perennial agriculture, by creating

agroforestry

systems using tree crops, shrubs, vines and,

herbaceous plants in highly productive symbiotic assem-

blages. The practice was originally oriented to subsistence

farms in Tasmania, which typically were small and on poor

land. It was then extended to include other landscapes, urban

settings, and climates worldwide, and has even been applied

to other systems such as houses and factories.

Permaculture as a Life Philosophy

Some consider permaculture a life philosophy. In this

context, permaculture emphasizes putting oneself into a

symbiotic relationship with Earth and one’s community.

Permaculture is oriented to place, with reliance on native

plants and a close awareness of the

ecosystem

. It revolves

around self-reliance, growing food and building attractive

energy-efficient structures from local materials. Designing

1066

a permaculture landscape begins with assessing a site’s native

features (such as soil structure, microclimates, cycles of decay,

and existing flora and fauna), in order to take advantage of

existing resources. This assessment also helps in selecting

and adapting technologies to the site. These technologies

might include methods of

composting

, gardening, irrigat-

ing, or generating electricity. Multifunctional living systems

abound in a typical permaculture design.

Examples of Permaculture Practices and Approaches

Animals are raised for their value as producers of food,

skins, and manure, and as pollinators, heat sources, gas pro-

ducers, earth tillers, and

pest

controller. For example, rabbits

raised in a rabbit hutch are fed kitchen scraps. Their drop-

pings fall into worm bins (vermiculture) as fodder for worms,

and the resulting worm castings are used to fertilize gardens.

In the winter, the rabbits are harvested for their meat and

fur. As another example, movable chicken hutch can be used

to place chickens in gardens where they effectively till and

fertilize the soil.

Particular varieties of trees are chosen for their fuel,

forage, material (for fences, structures and shelters), heat

reflector and windbreak values, as well as for crop diversifica-

tion. When they are young, the trees may act as hedgerows,

then grow to serve as a fuel source. Plants provide many

services for other plants. They act as trellises, for other screen

and shade them, provide nutrients, cross-fertilize them (as

happens with varieties of plums and nuts), help to repel

pests, prevent

erosion

, and provide spare parts (grafts) for

other plants. Fruit trees and vines are planted strategically

around a house to provide shade. In a home’s front yard,

attractive gardens feature high-yielding food, medicinal and

culinary plants where they are easily accessed. Some crops

are planted for their self-propagating patterns, such as leeks,

onions, potatoes, and garlic.

Water harvesting is an essential function in a perma-

culture landscape, and is supported by as many components

as possible.

Filtration

of water for animals may be provided

with shells and water plants. Water pathways are traced,

and systems are created for collecting it. Swales may direct

rain water and run-off to fruit trees. Run-off water from

culverts may be directed to ponds where water plants and

fish are raised, and where it can be used for

irrigation

and

firefighting. Water can be collected from roofs. Composting

toilets

and septic systems with planted

leaching

beds can

be employed.

Insects and crops are used to aerate the soil. Mulching,

growing green crops, composting, and strategic planting are

employed to build soil health. Permaculture grows forests

and shrubs to protect the soil, and uses plows that do not

turn the soil. Food crops, such as corn and legumes, are

chosen for their low-maintenance qualities and their ability

to fix

nitrogen

in the soil.