Environmental Encyclopedia

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Environmental Encyclopedia 3

Convention on International Trade in Endangered Species

background levels, that is, the concentrations found in simi-

lar, nearby, and unpolluted soils. Second, soil contaminant

levels may be acceptable if the soil does not produce leachate

with concentration levels above drinking water standards.

Such determinations are often based on a test called the

Toxics Characteristic Leaching Procedure which mildly

acidifies and agitates the soil. Contaminant levels in the

leachate below the maximum contaminant levels (MCLs)

in the federal

Safe Drinking Water Act

are acceptable.

Third, soil contaminant levels may be set in a determination

of health risks based on typical or worst case exposures.

Exposures can include inhalation of soils as dust, ingestion

of soil (generally by children), and direct skin contact with

soil. In part, these various approaches response to the com-

plexity of contaminant mobility and toxicity in soils and the

difficulty of pinning down acceptable and safe levels.

[Stuart Batterman]

ESOURCES

OOKS

Jury, W. “Chemical Movement Through Soil.” In Vadose Modeling of Or-

ganic Pollutants, edited by S. C. Hern and S. M. Melancon. Chelsea, MI:

Lewis Pub., 1988

ERIODICALS

Chen, C. T. “Understanding the Fate of Petroleum Hydrocarbons in the

Subsurface Environment.” Journal of Chemical Education 5 (1992): 357-59.

Contour plowing

Plowing the

soil

along the contours of the land. For example,

rather than plowing up-and-down the hill, the cultivation

takes place around the hill. By plowing along the contour,

less water runs down the hill, thereby reducing water

erosion

Contraceptives

see

Family planning; Male contraceptives

Convention on International Trade in

Endangered Species of Wild Fauna

and Flora (1975)

The Convention on International Trade in

Endangered

Species

of Wild

Fauna

and Flora (CITES), was signed in

1973 and came into force in 1975. The aim of the treaty

is to prevent international trade in listed endangered or

threatened animal and plant

species

and products made

from them. A full-time, paid secretariat to administer the

treaty was initially funded by the United Nations Environ-

317

mental Program, but has since been funded by the parties

to the treaty. By 2002, 158 nations had become party to

CITES, including most of the major

wildlife

trading na-

tions, making CITES the most widely accepted wildlife

conservation

agreement in the world. The parties to the

treaty meet every two years to evaluate and amend the treaty

if necessary.

The species covered by the treaty are listed in three

appendices, each of which requires different trade restric-

tions. Appendix I applies to “all species threatened with

extinction,” such as African and Asian

elephants

(Loxodonta

africana and Elephas maximus, the hyacinth macaw (Anodor-

hynchus hyacinthinus), and Queen Alexandria’s birdwing but-

terfly (Ornithoptera alexandrae). Commercial trade is gener-

ally prohibited for the over 900 listed species. Appendix II

applies to “all species which although not necessarily now

threatened with

extinction

may become so unless trade in

specimens of such species is subject to strict regulation,”

such as the polar bear, giant clams, and Pacific Coast mahog-

any. Trade in these species requires an export permit from

the country of origin. Currently, over 4,000 animals and

22,000 plants (mainly orchids) are listed in Appendix II.

Appendix III is designed to help individual nations control

the trade of any species. Any species may be listed in Appen-

dix III for any nation. Once listed, any export of this species

from the listing country requires an export permit. Usually

a species listed in Appendix III is protected within that

nation’s borders. These trade restrictions apply only to signa-

tory nations, and only to trade between countries, not to

practices within countries.

CITES relies on signatory nations to pass domestic

laws to carry out the principles included in the treaty. In

the United States, the

Endangered Species Act

and the

Lacey Act include domestic requirements to implement

CITES, and the

Fish and Wildlife Service

is the chief

enforcement agency. In other nations, if and when such

legislation is passed, effective implementation of these do-

mestic laws is required. This is perhaps the most problematic

aspect of CITES, since most signatory nations have poor

administrative capacity, even if they have strong desire for

enforcement. This is especially a problem in poorer nations

of the world, where monies for regulation of trade in endan-

gered species is forced down the agenda by more pressing

social and economic issues.

CITES can be regarded as moderately successful.

There has been steady progress toward compliance with the

treaty, though tremendous enforcement problems still exist.

Due to the international scope and size of world wildlife

trade, enforcement of CITES is estimated to be only 60–

65% effective worldwide. International trade in endangered

species is still big business; the profits from such trade can

be huge. In 1988, the world market for

exotic species

was

Environmental Encyclopedia 3

Convention on Long-Range Transboundary Air Pollution (1979)

estimated to be $5 billion, $1.5 billion of which was esti-

mated to be illegal. Among the most lucrative products

traded are reptile skins, fur coats, and ingredients for tradi-

tional drugs. If violations are discovered, the goods are con-

fiscated and penalties and fines for the violators are estab-

lished by each country. Occasionally, sanctions are imposed

on a nation if it flagrantly violates the convention.

[Christopher McGrory Klyza]

ESOURCES

OOKS

Fitzgerald, S. International Wildlife Trade: Whose Business Is It? Washington,

DC: World Wildlife Fund, 1989.

McCormick, J. Reclaiming Paradise: The Global Environmental Movement.

Bloomington: Indiana University Press, 1989.

Nichol, J. The Animal Smugglers. New York: Facts on File, 1987.

RGANIZATIONS

CITES Secretariat, International Environment House, Chemin des

Ane

mones , Cha

telaine, Geneva Switzerland CH-1219 (+4122) 917-

8139/40, Fax: (+4122) 797-3417, Email: cites@unep.ch, <http://

www.cites.org>

Convention on Long-Range

Transboundary Air Pollution (1979)

Held in Geneva in 1979 under the auspices of the United

Nations, the goal of the Convention on Long-Range Trans-

boundary

Air Pollution

was to reduce air

pollution

and

acid

rain

, particularly in Europe and North America. The accord

went into effect in March 1983. It was signed by the United

States and Canada, as well as European countries, and the

signatories agreed to cooperate in researching and monitor-

ing air pollution and to exchange information on developing

technologies for

air pollution control

. This convention es-

tablished the Cooperative Programme for Monitoring and

Evaluating of the Long-Range Transmission of Air Pollut-

ants in Europe, which was first funded in 1984. The coun-

tries that signed the treaty also agreed to reduce their sulfur

emissions 30% by 1993. All of the countries were able to

meet this goal, with many coutries reducing more than 50–

60% of their emissions.

[Douglas Smith]

ESOURCES

OOKS

Basic Documents of International Environmental Law. Boston: Graham &

Trotman, 1992.

Effectiveness of International Environmental Agreements: A Survey of Existing

Legal Instruments. Cambridge, England: Grotius, 1992.

318

Convention on the Conservation of

Migratory Species of Wild Animals

(1979)

The first attempt at a global approach to

wildlife manage-

ment

, the Convention on the

Conservation

of Migratory

Species

of Wild Animals was held in Bonn, Germany in

1979. The purpose of the convention was to reach an

agreement on the management of wild animals that migrate

“cyclically and predictably” across international boundaries.

Egypt, Italy, the United Kingdom, Denmark, and Sweden,

among other nations, signed an accord on this issue; the

treaty went into effect in 1983, but the United States and

Canada, as well as the former Soviet Union, still have not

agreed to it.

The challenge facing the convention was how to assist

nations that did not have

wildlife

management programs

while not disrupting those that had already established them.

The United States and Canada did not believe that the

agreement reached in Bonn met this challenge. Representa-

tives from both countries argued that the definition of a

migratory animal was too broad; it would embrace nearly

every game bird or animal in North America, including

rabbits, deer, and bear. But both countries were particularly

concerned that the agreement did not sufficiently honor

national sovereignty, and they believed it threatened the

effectiveness of the federal-state and federal-provincial sys-

tems that were already in place.

It is widely believed that the principal failure of this

convention was its inability to find language dealing with

federalist systems that was acceptable to all. The agreement

also came into conflict with other laws, particularly laws

governing national jurisdictions and territorial boundaries at

sea, but it is still considered an important advance in the

process of developing international environmental

agreements. See also Environmental law

[Douglas Smith]

ESOURCES

OOKS

Basic Documents of International Environmental Law. Boston: Graham &

Trotman, 1992.

Effectiveness of International Environmental Agreements: A Survey of Existing

Legal Instruments. Cambridge, England: Grotius, 1992.

Convention on the Law of the Sea

(1982)

During the age of exploration in the seventeenth century,

the Dutch lawyer Hugo Grotius formulated the legal princi-

Environmental Encyclopedia 3

Convention on the Prevention of Marine Pollution

ple that the ocean was free (Mare liberum), which became

the basis of the law of the sea. During the eighteenth century,

each coastal nation was granted sovereignty over an offshore

margin of three nautical miles to provide for better defense

against pirates and other intruders. As undersea exploration

advanced in the twentieth century, nations became increas-

ingly interested in the potential resources of the oceans. By

the 1970s, many were determined to exploit resources such

petroleum

on the continental shelf and manganese nod-

ules rich with metals on the deep ocean floor, but uncertain-

ties about the legal status of these resources inhibited in-

vestment.

In 1974 the United Nations responded to these con-

cerns and convened a Conference on the Law of the Sea,

at which the nations of the world negotiated a consensus

dividing the ocean among them. The participants drafted a

proposed constitution for the world’s oceans, including in

it a number of provisions that radically altered their legal

status. First, the convention extended the

territorial sea

from three to 22 nautical miles, giving nations the same

rights and responsibilities within this zone that they possess

over land. Negotiations were necessary to ensure that ships

have a right to navigate these coastal zones when going from

one ocean to another.

The convention also acknowledged a 200 nautical mile

Exclusive Economic Zone

(EEZ), in which nations could

regulate fisheries as well as resource exploration and exploita-

tion. By the late 1970s, over 100 nations had already claimed

territorial seas extending from 12 to 200 miles. The United

States, for example, claims a 200 mile zone. Today, EEZs

cover about one third of the ocean, completely dividing the

North Sea, the

Mediterranean Sea

, the Gulf of Mexico,

and the Caribbean among coastal states. They also encom-

pass an area that yields more than 90% of the ocean’s fish

catch, and they are considered a potentially effective means

to control

overfishing

because they provide governments

clear responsibility for their own fisheries.

The most heated debates during the convention, how-

ever, did not concern the EEZs, but involved provisions

concerning seabed mining.

Third World

nations insisted

that deep-sea metals were the common heritage of mankind,

and that their wealth should be shared. After fierce disagree-

ments, a compromise was reached in 1980 that would estab-

lish a new International Seabed Authority (ISA). Under the

plan, any national or private enterprise could take half the

seabed mining sites and the ISA would take the other half.

In exchange for mining rights, industrialized nations would

underwrite the ISA and sell it the necessary technology. In

December 1982, 117 nations signed the Law of the Sea

Convention at Montego Bay, Jamaica. President Ronald

Reagan refused to sign, citing the seabed-mining provisions

as a major reason for United States opposition. Two other

319

key nations, the United Kingdom and Germany, refused,

and 21 nations abstained. In order to become international

law, 60 nations must ratify the Law of the Sea Convention,

but although 159 nations have now become signatories, only

40 have actually ratified it. See also Coastal Zone Manage-

ment Act; Commercial fishing; Oil drilling

[David Clarke]

ESOURCES

OOKS

Law of the Sea: Protection and Preservation of the Marine Environment. New

York: United Nations, 1990.

Porter, G., and J. W. Brown. Global Environmental Politics. Boulder, CO:

Westview Press, 1991.

Simon, A. W. Neptune’s Revenge, The Ocean of Tomorrow. New York:

Franklin Watts, 1984.

Convention on the Prevention of

Marine Pollution by Dumping of

Waste and Other Matter (1972)

The 1972 International Convention on the Prevention of

Marine Pollution

by Dumping of Waste and Other Matter,

commonly called the London Dumping Convention, en-

tered into force on August 30, 1975. The London Dumping

Convention covers “ocean dumping” defined as any deliber-

ate disposal of wastes or other matter from ships, aircraft,

platforms, or other human-made structures at sea. The

dis-

charge

of sewage

effluent

and other material through pipes,

wastes from other land-based sources, the operational or

incidental disposal of material from vessels, aircraft, and

platforms (such as fresh or salt water), or wastes from seabed

mining are not covered under this convention.

The framework of the London Dumping Convention

consists of three annexes. Annex I contains a blacklist of

materials that cannot be dumped at sea. Organohalogen

compounds,

mercury

cadmium

, oil, high-level radioactive

wastes, warfare

chemicals

, and persistent

plastics

and other

synthetic materials that may float in such a manner as to

interfere with fishing or navigation are examples of sub-

stances on the blacklist. The prohibition does not apply

acid

and alkaline substances that are rapidly rendered

harmless by physical, chemical, or biological processes in the

sea. Annex I does not apply to wastes such as sewage

sludge

or dredge material that contain blacklist substances in trace

amounts.

Annex II of the convention comprises a grey list of

materials considered less harmful than the substances on the

blacklist. At-sea dumping of grey list wastes requires a special

permit from contracting states (countries participating in

the convention). These materials include wastes containing

Environmental Encyclopedia 3

Convention on Wetlands of International Importance (1971)

arsenic

lead

copper

, zinc, organosilicon compounds, cya-

nides, pesticides and radioactive matter not covered in Annex

I, and containers, scrap metals, and other bulky debris that

may present a serious obstacle to fishing or navigation. Grey

list material may be dumped as long as special care is taken

with regard to

ocean dumping

sites, monitoring, and meth-

ods of dumping to ensure the least detrimental impact on

the

environment

. A general permit from the appropriate

agencies of the contracting states to the Convention is re-

quired for ocean dumping of waste not on either list.

Annex III includes criteria that countries must con-

sider before issuing an ocean dumping permit. These criteria

require consideration of the effects dumping activities can

have on marine life, amenities, and other uses of the ocean,

and they encompass factors related to disposal operations,

waste characteristics, attributes of the site, and availability

of land-based alternatives.

The International Maritime Organization serves as

Secretariat for the London Dumping Convention, undertak-

ing administrative responsibilities and ensuring cooperation

among the contracting parties. As of 2001, there were 78

contracting parties to the Convention, including the United

States.

The London Dumping Convention covers ocean

dumping in all marine waters except internal waters of the

contracting states, which are required to regulate ocean

dumping consistently with the convention’s provisions.

However, they are free to impose stricter rules on their own

activities than those required by the convention. The London

Dumping Convention was developed at the same time as

the

Marine Protection, Research and Sanctuaries Act

1972 (Public Law 92-532), a law enacted by the United

States. The U.S. congress amended this act in 1974 to con-

form with the London Dumping Convention.

Most nations using the ocean for purposes of dumping

waste are developed countries. The United States completely

ended its dumping of sewage sludge following the passage

of the

Ocean Dumping Ban Act

(1988), which prohibits

ocean dumping of all sewage sludge and industrial waste

(Public Law 100-688). Britain and the North Sea countries

also intend to end ocean dumping of sewage sludge. During

the Thirteenth Consultative Meeting of the London Dump-

ing Convention in 1990, the contracting states agreed to

terminate all industrial ocean dumping by the end of 1995.

While the volume of sewage sludge and industrial

waste dumped at sea is decreasing, ocean dumping of

dredged material is increasing.

Incineration

at sea requires

a special permit and is regulated according to criteria con-

tained in an addendum to Annex I of the convention.

In 1996, the London Dumping Convention was re-

placed by the 1996 Protocol to the Convention on the Pre-

vention of Marine

Pollution

by Dumping of Wastes and

320

Other Matter, 1972. Among the changes is the “reverse list.”

The Protocol only allows dumping material that is listed in

Annex I, it is referred to as the “reverse list” since it com-

pletely reverses the original Annex I. Incineration at sea is

now completely banned, unless there is an emergency, as is

the exportation of waste to other countries for ocean dump-

ing. In 2001, the Protocol had been ratified by 16 states,

but needs to be ratified by 26, 15 of which must be Con-

tracting Parties to the Convention, in order to be put into

force. See also Marine pollution; Seabed disposal

[Marci L. Bortman]

ESOURCES

ERIODICALS

Duedall, I. W. “A Brief History of Ocean Disposal.” Oceanus 33 (Summer

1990): 29-33+.

Kitsos, T. R., and J. M. Bondareff. “Congress and Waste Disposal at Sea.”

Oceanus 33 (Summer 1990): 23-8.

U.S. House of Representatives. House Report No. 100-1090. Ocean

Dumping Ban Act Conference Report, 2nd Session, 100th Congress, 1990.

THER

National Ocean Servie, International Program Office. The Convention on

the Prevention of Marine Pollution by Dumping of Wastes and Other Matter,

London, 1972. [June 2002]. <http://international.nos.noaa.gov/conv/

ldc.html>.

Convention on Wetlands of

International Importance (1971)

Also called the Ramsar Convention or

Wetlands

Conven-

tion, the Convention on Wetlands of International Impor-

tance is an international agreement adopted in 1971 at a

conference held in Ramsar, Iran. One of the principal con-

cerns of the agreement was the protection of migratory wa-

terfowl, but it is generally committed, like much wetlands

legislation in the United States, to restricting the loss of

wetlands in general, because of their ecological functions as

well as their economic, scientific, and recreational value. The

accord went into effect in 1975, establishing a network of

wetlands, primarily across Europe and North Africa.

In 2002, there were 132 Contracting Parties, each of

whom was required to set aside at least one wetland reserve.

Over 1,178 national wetland sites have been established

totaling over 252.3 million acres (102.1 million ha). The

convention has secured protection for wetlands around the

world, but many environmentalists believe it has the same

weakness as many international conventions on the

environ-

ment

. There is no effective mechanism for enforcement.

Population growth

continues to increase political and eco-

nomic pressures to develop wetland areas around the world,

and there are no provisions in the agreement strong enough

Environmental Encyclopedia 3

Copper

to prevent nations from removing protected status from

designated wetlands.

[Douglas Smith]

ESOURCES

OOKS

Basic Documents of International Environmental Law. Boston: Graham &

Trotman, 1992.

Effectiveness of International Environmental Agreements: A Survey of Existing

Legal Instruments. Cambridge, England: Grotius, 1992.

RGANIZATIONS

The Ramsar Convention Bureau, Rue Mauverney 28, Gland , Switzerland

CH-1196 +41 22 999 0170 , Fax: +41 22 999 0169 , Email:

ramsar@ramsar.org, <http://www.ramsar.org/index.html>

Conventional pollutant

Conventional pollutants fall into five categories; the presence

of these pollutants is commonly determined by measuring

biochemical oxygen demand

, total suspended solids,

levels, the amount of fecal coliform, and the quantity of oil

and grease.

Biochemical oxygen demand (BOD) is the quantity

of oxygen required by

microorganisms

to stabilize five-day

incubated oxidizable organic matter at 68°F (20°C). Hence,

BOD is a measure of the

biodegradable

organic

carbon

and at times, the oxidizable

nitrogen

. BOD is the sum

of the oxygen used in organic matter synthesis and in the

endogenous

respiration

of microbial cells. Some industrial

wastes are difficult to oxidize, and bacterial seed is necessary.

In certain cases, an increase in BOD is observed with an

increase in dilution. It is hence necessary to determine the

detection limits for BOD.

Suspended solids interfere with the transmission of

light. Their presence also affects recreational use and aes-

thetic enjoyment. Suspended solids make fish vulnerable to

diseases, reduce their growth rate, prevent successful devel-

opment of fish eggs and larvae, and reduce the amount

of available food. The

Environmental Protection Agency

(EPA) restricts suspended matter to not more than ten per-

cent of the reasonably established amount for aquatic life.

This allows sufficient sunlight to penetrate and sustain

pho-

tosynthesis

. Suspended solids also cause damage to inverte-

brates and fill up gravel spawning beds.

The acidity or alkalinity of water is indicated by pH.

A pH of seven is neutral. A pH value lower than seven

indicates an acidic

environment

and a pH greater than

seven indicates an alkaline environment. Most aquatic life

is sensitive to changes in pH. The pH of surface waters

is specified to protect aquatic life and prevent or control

unwanted chemical reactions such as metal

ion

dissolution

321

in acidic waters. An increase in toxicity of many substances

is often observed with changes in pH. For example, an

alkaline environment shifts the ammonium ion to a more

poisonous form of un-ionized ammonia. EPA criteria for

pH are 6.5–9.0 for freshwater life, 6.5–8.5 for marine organ-

isms and 5–9 for domestic consumption.

Fecal

coliform bacteria

are yardsticks for detecting

pathogenic or disease causing bacteria. However, this rela-

tionship is not absolute because these bacteria can originate

from the intestines of humans and other warm blooded

animals. Prior knowledge of

river basins

and the possible

sources of these bacteria is necessary for a survey to be

effective. The strictest EPA criteria for coliforms apply to

shellfish, since they are often eaten without being cooked.

Common sources of oil and grease are

petroleum

derivatives and fats from vegetable oil and meat processing.

Both surface and domestic waters should be free from float-

ing oil and grease. Limits for oil and grease are based on

values. LC

is defined as the concentration at which

50% of an aquatic

species

population perishes. EPA crite-

rion is for a 96-hour exposure, and during this period the

concentration of individual petrochemicals should not ex-

ceed 0.01 of the LC

median. Oil and grease contaminants

vary in physical, chemical, and toxicological properties be-

sides originating from different sources. See also Industrial

waste treatment; Sewage treatment; Wastewater; Water pol-

lution; Water quality

[James W. Patterson]

ESOURCES

OOKS

Viessman Jr., W., and M. J. Hammer. Water Supply and Pollution Control.

New York: Harper & Row, 1985.

Copper

A metallic element with an atomic number of 29. It is

abbreviated Cu and has an atomic weight of 63.546. Copper

is a micronutrient which is needed in many proteins and

enzymes. Copper has been and is frequently used in piping

systems which convey potable water. Corrosive waters will

leach copper from the pipelines, thereby exposing consumers

to copper and possibly creating bluish-green stains on house-

hold fixtures and clothes. The staining of household fixtures

becomes a nuisance when copper levels reach 2–3 mg/l. The

drinking water standard for copper is 1 mg/l. It is a secondary

standard based on the potential problems of staining and

Environmental Encyclopedia 3

Coprecipitation

Copper mining

see

Ashio, Japan; Ducktown, Tennessee;

Sudbury, Ontario

Coprecipitation

Inorganic contaminants, such as

heavy metals

, which ex-

hibit toxicity effects when present at low levels, can be diffi-

cult to treat. The level of toxicity can be well below the

metal’s solubility concentration, and for this reason precipita-

tion, a common treatment method for the removal of heavy

metal, does not provide the needed

effluent

quality.

Cad-

mium

, for instance, has a reported maximum contaminant

level (MCL) of 10 ␮g/l, with a 5 ␮g/l proposed level. Based

upon theoretical solubility calculations, alkaline precipitation

may only reduce the level of cadmium to 140 ␮g/l. Hence,

additional methods of

wastewater

treatment are often re-

quired to meet environmental regulations. One such treat-

ment technique is chemical coprecipitation.

Coprecipitation is a process in which a solid is precipi-

tated from a solution containing other ions. These ions are

incorporated into the solid by

adsorption

on the surface of

the growing particles, physical entrapment in the pore spaces,

or substitution in the crystal lattice. Adsorption is one of

the principle mechanisms of coprecipitation. It is a process

in which the solid

species

, or adsorbent, is added to a

solution containing other ions, called adsorbates. In this case,

the adsorbates are bound to the solid’s surface by physical or

chemical interactions between one adsorbate and the ad-

sorbent.

In solution, coprecipitation and adsorption are thus

related by the time during which an adsorbate is present.

The type of adsorbent present also affects the extent of

ion

uptake from solution. One solid used to perform this

treatment is ferric oxide. For example, iron coprecipitation

of cadmium has been reported to yield a residual cadmium

concentration of about 3 ␮g/l. Several solid and solution

variables must be considered when designing and optimizing

coprecipitation as a treatment option. These include the

equilibrium concentration of the species in solution, the

suspension

, and the presence of other interacting ions.

Also, the properties of the solid adsorbent are important.

These include type of solid formed, surface area available,

age, and surface charge. In short, coprecipitation is controlled

by a number of important variables which are specific to a

given system. Thus treatability studies must be performed

to fully optimize this wastewater treatment process and pro-

322

duced the necessary effluent quality. See also Hazardous

waste; Pollution control; Sewage treatment; Toxic substance

[James W. Patterson]

ESOURCES

OOKS

Anderson, M., and A. Rubin. Adsorption of Inorganics of Solid-Liquid Inter-

faces. Ann Arbor, MI: Ann Arbor Science, 1981.

Leckie, J., et al. Adsorption/Coprecipitation of Trace Elements from Water

with Iron Oxyhydroxide. EPR5 Final Report, 1980.

THER

A Review of Solid-Solution Interactions and Implications for the Control of

Trace Inorganic Materials in Water Treatment. AWWA Committee Report.

Vol. 80, 1988.

Coral bleaching

Coral bleaching is the whitening of coral colonies due to the

loss of the symbiotic algae, zooxanthellae, from the tissues of

coral polyps. It is mostly caused by stress. The host coral

polyp provides the algae with a protected

environment

and

a supply of

carbon dioxide

for its photosynthetic processes.

The golden-brown algae serve as a major source of nutrition

and color for the coral. The loss of the algae exposes the

translucent calcium carbonate skeletons of the coral colony,

and the corals look “bleached.” Corals may recover from

short-term bleaching (less than a month), but prolonged

bleaching causes irreversible damage and

mortality

, for

without the algae, the corals starve and die. However, even

a sublethal stress may result in increased susceptibility of

corals to infections, with resulting significant mortality. Pop-

ulations of sea urchins, parrot fish, and worms erode and

weaken dead reef skeletons, and the reef can be destroyed

by storm surges.

The means by which corals expel the zooxanthellae

are not yet known. In laboratory experiments the zooxanthel-

lae are released into the gut of the polyp and then expelled

through the mouth; however this method has not been ob-

served in the environment. Another hypothesis is that the

stressed corals provide the algae with fewer nutrients, which

results in the algae leaving the corals. Another possibility is

that the algae may produce oxides under stress, which ad-

versely affect the algae.

Bleaching may be caused by a number of stresses or

environmental changes, including disease, excess shade, in-

creased levels of

ultraviolet radiation

sedimentation

pol-

lution

salinity

changes, exposure to air by low tides or low

sea level, and increased temperatures. Coral bleaching is most

often associated with increased sea surface temperatures, as

corals tolerate only a narrow temperature range of between

about 77–84°F (25–29°C).

Environmental Encyclopedia 3

Coral reef

Historically bleaching was observed on a small scale,

such as in overheated tide pools. However, in the early to

mid 1980s, coral reefs around the world began to experience

large scale bleaching, with a bleaching event occurring some-

where in the world almost every year. In 1998, coral reefs

around the world suffered the most extensive and severe

bleaching and subsequent mortality in recorded history, in

the same year that tropical sea surface temperatures were

the highest in recorded history. Coral bleaching was reported

in at least 60 countries and island nations in the Pacific

Ocean, Indian Ocean, Red Sea, Persian Gulf, and the Carib-

bean. Only the Central Pacific region was spared. About

16% of the world’s reefs were lost in a period of only nine

months. Previous bleaching events had only affected reefs

to a depth of less than 49 ft (15 m), but in 1998, the

bleaching extended as deep as 164 ft (50 m). The reason

sea temperatures throughout the world were so warm in

1998 remains controversial and uncertain. Three theories

have been developed—natural

climate

variability, El Ninn

and other climatic variations, and global warming. By the

end of 2000, 27% of the world’s reefs had been lost, with

the largest single cause being the coral bleaching event of

1998. Only half of the reefs lost during 1998 will probably

recover, which will add to the 11% already lost to human

impacts such as

sediment

and

nutrient

pollution and over-

exploitation.

Many of the bleached

coral reef

ecosystems may re-

quire decades to recover. Human populations dependent on

the reefs will lose fisheries, shoreline protection, and tourism

opportunities. Trends of the past century indicate that coral

bleaching events may become more frequent and severe if

the climate continues to warm.

[Judith L. Sims]

ESOURCES

OOKS

Wilkinson, Clive. ed.Status of Coral Reefs of the World: 2000.Queensland,

Australia: Australian Institute of Marine Science, 2000.

THER

Pomerance, Rafe. “Coral Bleaching, Coral Mortality, and Global Climate

Change".Report to U.S. Coral Reef Task Force, Bureau of Oceans and Interna-

tional Environmental and Scientific Affairs, U.S. Department of State. March

5, 1999. [cited May 31, 2002]. <http://www.state.gov/www/global/

global_issues/coral_reefs/990305_coralreef_rpt.html>.

Coral reef

Coral reefs represent some of the oldest and most complex

communities of plants and animals on Earth. About 200–

400 million years old, they cover about 231,660 mi

(600,000

) worldwide. (The most popular reefs range from 5,000–

323

10,000 years old.) The primary structure of a coral reef is a

calcareous skeleton formed by marine invertebrate organisms

known as cnidarians, which are relatives of sea anemones.

Corals are found in most of the oceans of the world, in deep

as well as shallow seas and temperate as well as tropical

waters. But corals are most abundant and diverse in relatively

shallow tropical waters, where they have adapted to the

constant temperatures provided by these waters. The reef-

forming corals, or hermatypic corals, have their highest di-

versity in the Indian and Pacific Oceans, where over 700

species

are found. By contrast, the Atlantic Ocean provides

the

habitat

for less than 40 species. Other physical con-

straints needed for the success of these invertebrate commu-

nities are clear water, a firm substrate, high

salinity

, and

sunlight. Clear water and sunlight are required for the symbi-

otic unicellular plants that live in the surface tissues of the

coral polyps. This intimate plant-animal association benefits

both participants. Corals obtain oxygen directly from the

plants and avoid having to excrete nitrogenous and phos-

phate waste products because these are absorbed directly as

nutrients by the plants.

Respiration

by the coral additionally

provides

carbon dioxide

to these plants to be used in the

photosynthetic process.

The skeletons of hermatypic coral play a major role

in the formation of coral reefs, but contributions to reef

structure, in the form of calcium carbonate, come from a

variety of other oceanic species. Among these are red algae,

green algae, foraminifers, mollusk shells, sea urchins, and

the exoskeletons of many other reef-dwelling invertebrates.

This limestone infrastructure provides the

stability

needed,

not only to support and protect the delicate tissues of the

coral polyps themselves, but also to withstand the constant

wave action generated in the shallow, near-shore waters of

the marine

ecosystem

There are essentially three types of coral reefs. These

categories are fringing reefs, barrier reefs, and atolls. Fringing

reefs form borders along the shoreline. Some of the reefs

found in the

Hawaiian Islands

are fringing reefs. Barrier

reefs also parallel the shoreline but are found further offshore

and are separated from the coast by a

lagoon

. The best

example of this type of reef is the

Great Barrier Reef

off

the coast of

Australia

. Because the coral colonies form an

interwoven network of organisms from one end of the reef

to the other, this is the largest individual biological feature

on earth. The Great Barrier Reef borders about 1,250 mi

(2011 km) of Australia’s northeast coast. The second largest

continuous barrier reef is located in the Caribbean Sea off

the coast of Belize, east of the Yucatan Peninsula. The third

type of reef, the atoll, is typically a ring-shaped reef, from

which several small, low islands may project above the surface

of the ocean. The ring structure is present because it repre-

sents the remains of a fringing reef that formed around an

Environmental Encyclopedia 3

Coral reef

oceanic

volcano

. As the volcano eroded or collapsed, the

outwardly-growing reef is ultimately all that remains as a

circle of coral. Possibly the most infamous atoll is the

Bikini

Atoll

, which was the site of the United States’

hydrogen

bomb tests during the 1940s and 1950s.

Besides the physical structure of the coral and the reef

itself, the most significant thing about these structures is

the tremendous diversity of marine life that exists in, on,

and around coral reefs. These highly productive marine eco-

systems may contain over 3,000 species of fish, shellfish,

and other invertebrates. About 33% of all of the fishes of

the world live and depend on coral reefs. This tremendous

diversity provides for a huge commercial fishery in countries

such as the Philippines and Indonesia. With the advent and

availability of SCUBA gear to the general public in this half

of this century, the diversity of life exhibited on coral reefs

has been a great lure for tourists to these ecosystems through-

out the world.

Even with their calcium carbonate skeleton and exqui-

site beauty, coral reefs are being degraded and destroyed

daily, not only by natural events such as constant wave action

and storm surges, but, more importantly, by the actions of

man. Of the 109 countries that have coral reef formations

within their territorial waters, 90 are losing them because

of man-induced

environmental degradation

. Most is the

result of physical abuse or

pollution

which alters the narrow

range of physical and chemical parameters necessary for the

coral, or their plant symbionts, to remain viable and thrive.

Today, 10% of the world’s coral reefs are completely de-

graded, 30% have reached a critical stage. Scientists have

determined that if degradation at this rate continues, 70%

of all coral reefs could be gone in 40 years. Reefs can be

salvaged however. In 1995, participants from 44 countries

representing governments, nongovernmental organizations,

international development agencies, and the private sector

gathered to launch the International Coral Reef Initiative.

In 1997, some 1,400 participants declared the year as the

International Year of the Reef, a period they hoped would

heighten awareness and further reef salvage activities

worldwide.

These reefs, most of which are between 5,000 and

10,000 years old, and some of which have been building on

the same site for over a million years, are being degraded

and destroyed by a vast array of water pollutants.

Silt

, which

washes into the sea from

erosion

of clearcut forests miles

inland, cloud the water or smother the coral, thus prohibiting

the photosynthetic process from taking place.

Oil spills

and

other toxic or hazardous

chemicals

that find their way into

the marine ecosystem through man’s actions are killing off

the coral and/or the organisms associated with the reefs.

Mining of coral for building materials takes a massive toll

on these communities. Removal of coral to supply the ever

324

A coral reef. (Phototake. Reproduced by permission.)

increasing demand within the

aquarium trade

is destroying

the reefs as well. The tremendous interest in and appeal of

marine aquaria has added another problem to this dilemma.

In the race to provide the aquarium market with a great

variety of beautiful, brilliantly-colored, and often quite rare,

marine fishes, unscrupulous collectors, who are selling their

catches illegally merely for the short term monetary gain,

spray the coral heads with poison solutions (including cya-

nide) to stun the fishes, causing them to abandon the reefs.

This efficient means of collecting reef fishes leaves the coral

head enveloped in a cloud of poison, which ultimately kills

that entire section of the reef.

An unusual phenomenon has developed within the

past decade with regard to coral reefs and pollution. In the

Florida Keys in the early 1980s divers began reporting that

the coral, sea whips, sea fans, and sponges of the reefs,

around which they had been swimming, had turned white.

They also reported that the waters felt unusually warm. The

same phenomenon occurred in the Virgin Islands in the late

1980s. As much as 50% of the reef was dying due to this

bleaching effect. Scientists are still studying these occur-

rences; however, many feel that it is a manifestation of global

warming, and that a mere change in the water temperature

around the coral reefs of 2–3°C is inducing the bleaching

and death of the coral.

Environmental Encyclopedia 3

Corporate Average Fuel Economy standards

Tourism and

recreation

are inadvertently degrading

coral reefs throughout the world as well. Coral is being

destroyed by the propellers of recreational boats as well as

divers who unintentionally step on coral heads, thus breaking

them to pieces, and degrading the very structure of the

ecosystem they came to see. Many of the reefs undergoing

this degradation are sections that have been set aside for

protection. Even with almost a quarter of a million square

miles of coral reefs in the world, and about 300 protected

regions in 65 countries, ever increasing levels of near-shore

pollution, coupled with other acts of man, may be destroying

these extremely complex communities of marine organisms

at a rate faster than we can control.

[Eugene C. Beckham]

ESOURCES

OOKS

Brown, B., and J. Ogdon. “Coral Bleaching.” Scientific American 268 (Janu-

ary 1993): 64-70.

Derr, M. “Raiders of the Reef.” Audubon 94 (February 1992): 48-56.

Falkner, D. This Living Reef. New York: The New York Times Book

Co., 1974.

Corporate Average Fuel Economy

standards

In 1975, as part of the response to the Arab

oil embargo

of 1973–1974, the U.S. Congress and President Richard

Nixon passed the

Energy Policy

and

Conservation

Act.

One of a number of provisions in this legislation intended

to decrease fuel consumption was the establishment of fuel

economy standards for passenger cars and light trucks sold in

the United States. These Corporate Average Fuel Economy

(CAFE) standards require that each manufacturer’s entire

production of cars or trucks sold in the United States meet

a minimum average fuel economy level. Domestic and im-

port cars and trucks are segregated into separate fleets, and

each must meet the standards individually. Any manufac-

turer whose fleet(s) fails to meet the standard is subject to

a fine, based on a CAFE shortfall times the total number

of vehicles in the particular fleet. Manufacturers are allowed

to generate CAFE credits for overachievement in a single

year, which may be carried forward or backward up to three

years to cover other shortfalls in mileage. This helps to

smooth the effects of model introduction cycles or market

shifts.

CAFE standards took effect in 1978 for passenger

cars and 1979 for light trucks. Truck standards originally

covered vehicles under 6,000 lb (2,724 kg) gross vehicle

weight (GVW), but in 1980, they were expanded to trucks

up to 8,500 lb (3,632 kg). Car standards were set at 18 mpg

325

for 1978, and increased annually to 27.5 mpg for 1985 and

beyond. Manufacturers responded with significant vehicle

downsizing, application of new powertrain technology, and

reductions in aerodynamic drag and tire friction. These ac-

tions helped improve average fuel economy of U.S.-built

passenger cars from 13 mpg in 1974 to 25 mpg by 1982.

The fall of

gasoline

prices following an embargo in 1980–

1981 encouraged consumers to purchase larger vehicles. This

mix shift slowed manufacturers’ CAFE improvement by the

mid-1980s, despite continued improvements in individual

model fuel economy, since CAFE is based on all vehicles

sold. The Secretary of

Transportation

has the authority to

reduce the car CAFE standards from 27.5 mpg to 26 mpg.

This authority was used in 1986 when it became clear that

market factors would prevent CAFE compliance by a large

number of manufacturers.

A separate requirement to encourage new car fuel effi-

ciency was created through the Energy Tax Act of 1978.

This act created a “Gas Guzzler” tax on passenger cars whose

individual fuel economy value fell below a certain threshold,

starting in 1980. The tax is progressively higher at lower

fuel economy levels. This act has since been amended both

to increase the threshold level and to double the tax. The

Gas Guzzler tax is independent of CAFE standards.

Environmental groups have long favored increasing

the CAFE standards to reduce oil consumption and

pollu-

tion

. At the same time, the

automobile

industry has fought

hard to avoid raising mileage standards, claiming increased

regulation would reduce competitiveness and cost jobs. After

the

Persian Gulf War

in 1991, some members of Congress

proposed raising CAFE standards to 45 mpg for cars and

35 mpg for light trucks by 2001. Proponents of the plan

claimed it would save 2.8 million barrels of oil per day, or

more oil than is imported from Persian Gulf countries (about

2.4 million barrels per day in 2000). Strongly opposed by

the automobile industry, the efficiency increase failed in

Congress.

Cheap oil prices in the 1990s decreased Americans’

concerns about fuel efficiency, and sales of larger cars

boomed. Since 1988, nearly all technology gains in automo-

bile efficiency have been offset by increased weight and

power in new vehicles. The popular Sport Utility Vehicle

(SUV), decried by environmentalists, became the new model

of gas guzzler. Due to the “SUV loophole” in the CAFE

laws, the SUV was classified as a light truck and was ex-

empted from higher mileage standards and fines for ineffi-

ciency, although opponents of the vehicles claim that they

are used more like cars and should be classified as such. By

law, SUVs can emit up to five times more

nitrogen oxides

than cars, and have a lower fleet mileage standard of 20.7

mpg. By 2001, SUVs and light trucks accounted for nearly

half of all new automobiles sold. Because of the high sales

Environmental Encyclopedia 3

Corrosion and material degradation

of large vehicles, United States automobile efficiency reached

its lowest point in 21 years in 2001, despite new technology.

Another battle between environmentalists and the au-

tomobile industry occurred in March 2002, when Congress

considered raising CAFE standards by 50% by the year 2015.

Environmental and other groups claimed that increased effi-

ciency would reduce America’s dependence on foreign oil,

would reduce pollution and

greenhouse gases

in the

envi-

ronment

, and eliminate the need to drill for oil in sensitive

regions such as the

Arctic National Wildlife Refuge

(ANWR) and offshore areas. The bill was strongly opposed

by the automobile industry, and did not pass.

[Brian Geraghty and Douglas Dupler]

ESOURCES

ERIODICALS

Gelbspan, Ross. “A Modest Proposal to Stop Global Warming.” Sierra,

May/June 2001, 63.

Hakim, Danny. “M.P.G. or G.P.M.?.” New York Times, 12 March

2002, WK2.

THER

Alliance to Save Energy Factsheet on Transportation and Energy. [2002].

<http://www.ase.org>.

Corrosion and material degradation

Corrosion or degradation involves deterioration of material

when exposed to an

environment

resulting in the loss of

that material, the most common case being the corrosion of

metals and steel by water. The changes brought about by

corrosion include weight loss or gain, material loss, or

changes in physical and mechanical properties.

Metal corrosion involves oxidation-reduction reactions

in which the metal is lost by dissolution at the anode (oxida-

tion). The electrons travel to the cathode where the reduction

takes place, while s move through a conducting solution or

electrolyte. A positive and a negative pole, called the cathode

and the anode respectively, are thereby created with a current

flow between them. Thus the process of corrosion is basically

electrochemical.

For corrosion to occur, certain conditions must be

present. These are: (1) a potential difference between the

cathode and the anode to drive the reaction; (2) an anodic

reaction; (3) an equivalent cathodic reaction; (4) an electro-

lyte for the internal circuit; (5) an external circuit where

electrons can travel. Sometimes, polarization of the anodic

and the cathodic reactions must be taken into consideration.

Polarization is a change in equilibrium

electromagnetic

field

of a cell due to current flow. It has been reported that

polarization may retard corrosion, as in the accumulation of

unreacted

hydrogen

on the cathode.

326

In the corrosion of iron in water, the reactions differ

according to whether or not oxygen is present. The common

reactions that take place in a deaerated medium are essen-

tially an oxidation reaction releasing ferrous

ion

into solution

at the anode and a reduction reaction releasing hydrogen gas

at the cathode. In the presence of oxygen, a complementary

cathode reaction involves oxygen being reduced to water.

Degradation of concrete, on the other hand, depends

on the composition of cement and the aggressive action of

the water in contact with it. Some forms of corrosion may

be visibly apparent, but some are not. Surface corrosion,

corrosion at discrete areas, and anodic attack in a two-metal

corrosion may be readily observed. A less identifiable form,

erosion-corrosion, is caused by flow patterns that cause abra-

sion and wear or sweep away protective films and accelerate

corrosion. Another form of corrosion which involves the

selective removal of an alloy constituent requires another

means of examination. Cracking, a form of corrosion which

is caused by the simultaneous effects of tensile stress and a

specific corrosive medium, could be verified by microscopy.

Some measures adopted to prevent corrosion in metals

are cathodic protection, use of inhibitors, coating, and the

formation of a passivating film. Protection of concrete, on

the other hand, can be achieved by coating, avoiding corro-

sive

of the water with which the concrete is in contact,

avoiding excessive concentrations of ammonia, and avoiding

deaeration in pipes. See also Hazardous waste sites; Seabed

disposal; Waste management

[James W. Patterson]

ESOURCES

OOKS

Dillon, C. P. Corrosion Control in the Chemical Process Industries. New York:

McGraw-Hill, 1986.

Fontana, M. G., and N. D. Greene. Corrosion Engineering. New York:

McGraw-Hill, 1967.

Weber, W., Jr. Physicochemical Processes for Water Quality Control. New

York: Wiley-Interscience, 1972.

Cost-benefit analysis

Environmentalists might believe that total elimination of

risk that comes with

pollution

and other forms of

environ-

mental degradation

is possible and even desirable, but

economists argue that the benefits of risk elimination have

to be balanced against the costs. Measuring risk is itself very

complicated.

Risk analysis

in the case of pollution, for

instance, involves determining the conditions of exposure,

the adverse effects, the levels of exposure, the level of the

effects, and the overall contamination. Long

latency

peri-

ods, the need to draw implications from laboratory studies