|Biodiversity and Conservation|
source ref: biobook.html
Florida Coastal Zone Color Scanner Image (CZCS) of a Gymnodinium breve bloom, from the USF/DMS - REMOTE SENSING LABORATORY
DDT (dichloro diphenyl trichloro ethane)
PCBs (polychlorinated biphenyls)
Tributyltin in anti-fouling paint
AIR POLLUTION AND ACID RAIN
ENDOCRINE DISRUPTING CHEMICALS
DISAPPEARANCE OF AMPHIBIANS
Check the Environmental Scorecard for your home town!
Pollution is an increasingly important factor determining the health and distribution of wildlife and biodiversity. We will discuss a few examples where the biological effects have been demonstrated or at least strongly suspected.
Starting in the 1940's, the chlorinated hydrocarbon DDT was used in vast quantities all over the world for killing insects. It was cheaper and much more effective than other insecticides against nearly all insects. It saved millions of lives by killing the mosquitoes that spread malaria and saved millions from starvation by killing crop pests. Paul Müller of Switzerland won the Nobel prize for discovering it.
But: in the 1950's and 1960's there was an alarming decline in the populations of several predatory birds, particularly fish-eaters such as bald eagles, cormorants, ospreys and brown pelicans but also including the Peregrine Falcon (see Chapter 8), which is a predator on other birds. The Brown Pelican, bald eagle and osprey almost went extinct.
DDT is toxic at high levels; but at lower levels it interferes with calcium deposition in eggshells, causing them to be thin, fragile, and often crushed by the parents in the nest.
Although DDT was suspected, the levels to which the birds had been exposed were nowhere near high enough to have killed them. But when the bird's bodies were analyzed, they were found to have up to one million times the concentration that was present in the sprayed water. This led to the discovery of bioaccumulation, which means the steady increase in concentration of a contaminant with increasing level in the food chain. In the case of DDT, it results from the following factors:
The DDT episode led to the publication of a famous book, Silent Spring by Rachel Carson in 1963. It led to a great increase in environmental awareness. DDT was banned in the U.S. in 1972 by the federal government, which found that it "had an adverse impact on wildlife" and "should be considered a potential carcinogen". However, DDT released before that time is still present in the environment and in various organisms in the process of bioaccumulation. The worst example is off the Palos Verdes Peninsula.
Between 1950 and 1970 hundreds of tons of DDT were released into the coastal waters of Los Angeles and Orange counties, California. Much of it came directly from the Montrose Chemical Company plant in San Pedro, and was discharged through the L.A. County sewage lines. Kelp beds off the coast disappeared, white sea bass numbers dwindled and Dover sole suffered from fin rot. It is estimated that there are 200 tons of DDT spread over a 20 square mile area of the sea bed off the Palos Verdes Peninsula, and the Environmental Protection Agency has designated the area as a Superfund site.
The DDT dump is probably the reason for high levels of DDT in present-day local fish and marine mammals. Although the levels measured in sewage outfalls, sediments, and fish have decreased since DDT was banned, the levels in blubber of local dolphins have not declined. In April 1990, the Department of Fish and Game outlawed harvesting of white croaker, a bottom-feeding fish, off Palos Verdes Peninsula, because of high levels of DDT and PCBs found in these fish. Commercial fishing is completely banned along the Palos Verdes coast. In 1999 fishermen were still being warned not to eat white croaker caught in this area. Under an agreement reached in December 2000, Montrose and three other companies will pay $73 million to clean up the DDT. Dramatic improvements have been made in the control of pollution from identifiable point sources, but non-point source pollution is proving much more difficult to control.
DDT is still used in Mexico, Central America, and Asia, mainly inside houses for mosquito control. It is still being manufactured in Mexico, China and India. Mexico announced in 1996 that it is planning to ban it within 10 years.
Beluga whales in the St. Lawrence River are heavily contaminated with PCBs and DDT, and 20% of the stranded animals that have been investigated were found to have cancer.
Scientists from the University of California, Santa Cruz reported in a 1997 study that sea otters and bald eagle eggs from the western Aleutians still carry potentially harmful levels of DDT and other contaminants such as PCBs (see section below). Bald eagle eggshells contained elevated levels of both DDT and PCBs. Eagles on the island with the highest levels of DDT are reproducing at half the rate of those on other islands. The concentration of DDT in eggshells increases steadily in a westerly direction along the island chain, indicating that the DDT comes from Asia via wind and water currents.
Some other chlorinated hydrocarbons were banned in 1975. Since then, many of the affected bird species have recovered and different types of chemicals (e.g. malathion, an organophosphate) are used to kill insects. But a continuing problem (other than pollution) is the evolution of insecticide resistance - it has now been found in over 500 species of insects and mites.
Endosulfan is a chlorinated hydrocarbon still in use to control insects and mites on 60 U.S. crops, including many fruits and vegetables, alfalfa, barley and Christmas trees. It is persistent, bioaccumulative and probably an endocrine disrupter and is suspected of having caused dozens of fatalities. It is being considered by the EPA for re-registration.
Causes of Lymph Cancers
Unknown Contaminant Found In Seabird Eggs
WWF: Global Toxics: What's New
Pesticide use in California
EPA Caught Between Farmers, Food Safety Fears
These compounds were manufactured beginning in the 1930's as non-flammable insulators and heat-dissipators in capacitors and transformers, hydraulic fluids, paint additives and plasticizers. PCB's have been found to cause liver damage, affect calcium metabolism, and to interfere with reproduction in seals by causing pathological changes in the reproductive system. Production of PCB's was stopped in 1977 and open disposal was banned in 1979, but due to their stability and bioaccumulation, they are still being detected at high levels in animal tissues. This is a global problem; the highest PCB levels in human samples were found in Eskimos. Killer whales off the coast of Washington State and Vancouver Island have the highest levels of PCBs found in wild mammals (up to 250 parts per million), and their populations are declining. Western Aleutian sea otter tissue contained twice the concentration of PCB than typically found in otters living along the central California coast, and 40 times as much as in otters from a relatively uncontaminated site in southeast Alaska.
The PCBs That are showing up at such high levels in the Arctic are probably not coming from local sources but are being concentrated at high latitudes by the phenomenon of global distillation. Many organic materials including PCBs evaporate rapidly from the soils of warm latitudes, but then condense and come back to the surface in rain and snow at high latitudes.
For 30 years, efforts to re-establish reproducing populations of lake trout in four of the five Great Lakes failed. The reason for this might be the high levels of dioxin and related chemicals in these waters. Dioxin, the chemical that led to the evacuation of Times Beach and Love Canal, is formed during the incineration of chlorine-containing wastes, the manufacturing of polyvinyl chloride (PVC) plastics, the production of chemicals like herbicides, pesticides and chlorinated benzenes, and the chlorine-bleaching of wood pulp and paper. The levels in Lake Ontario were high enough from 1945 to 1975 to have resulted in zero survival of young trout. Female fish accumulate dioxin-like chemicals in their bodies and transfer some of these toxins to their eggs, and this can cause the fish's offspring to die soon after hatching.
Dioxin and related chemicals can cause a range of adverse health effects in humans including reproductive and immune system disorders, alteration of fetal development, and cancer (EPA Science Advisory Board, October 1995). Dioxin was the contaminant in the herbicide Agent Orange, used as a defoliant in the Vietnam war and thought to have caused numerous health problems in veterans of that war.
The pulp and paper industry has historically discharged dioxin and other environmental toxins into rivers and streams. Legislation enacted by both the United States and Canadian governments restricting those activities and the installation of state-of-the-art pollution-control technologies have drastically lowered the pollutants in paper mill effluent. These measures have been costly but have succeeded in lowering the levels of dioxin and similar compounds to undetectable levels. As a result, the general consensus among business, scientific, and environmental interests was that the pulp and paper pollution problem had been solved. There has even been talk about relaxing some of the more stringent regulations.
A 1997 study by Canadian researchers brings all of that into doubt, however. Baby Chinook salmon exposed to low levels of supposedly non-toxic pulp mill effluents routinely released into Canada's upper Fraser River in British Columbia showed evidence of serious genetic damage. This was surprising given that the Prince George paper mill there is outfitted with the most modern anti-pollution technology and operates in accordance with British Columbia pollution guidelines that are among the most stringent anywhere. This situation is illustrative of a common problem in managing our environment: our basic understanding of how ecosystems function and how external events influence them is seriously inadequate. For example, the current standard for non-toxicity of pulp and paper mill effluent is the ability of fish to survive for four days in pure effluent. This assays acute toxicity but fails to address the impact of long-term exposure of living organisms to low levels of pollutants. The Fraser River study clearly shows that chronic exposure to unknown toxins or to undetectable levels of known toxins can have serious effects.
Recent evidence suggests that the toxin tributyltin (TBT) used in anti-fouling paint on ships may be accumulating in the food chain and be causing a decline in populations of sea otters and other marine mammals. TBT is one of the most toxic chemicals now being released into the aquatic environment.
The best-documented effects of TBT are on marine snails. It causes abnormalities in shell development, and in the development of the reproductive system, leading to population declines and disappearance of entire species in some areas. A species called the purple snail has been wiped out in many areas by this toxin. The compound was also responsible for extensive damage to the French oyster industry at the beginning of the 1980s.
When the effects of TBT on marine snails were documented, an international ban on the chemical was instituted in the early 1990s. However, it applies only to vessels under 25 meters in length. In 1998, the International Maritime Organisation (IMO) adopted a resolution to completely ban the application of TBT by January 1, 2003.
The population of sea otters along the California coast between Point Conception and Monterey Bay decreased 12% in 1998 to 1,937 otters. They continued to decline in 1998-1999 but recovered by about 10% in 2000. Evidence suggests that TBT may impair the animals' immune defenses and thereby lead to an increase in infectious disease. The chemical has been found in 29 species of marine mammals. Another possible cause of sea otter deaths is parasitic diseases from terrestrial animals that reach the otters through sewage or runoff.
Persistent Organic Pollutants in the Arctic
Wild bird populations have also suffered through exposure to another type of pesticide, organophosphates. For example, most states in the U.S. have banned the organophosphate fenthion, but Florida continues to spray the pesticide over 2 million acres each year and, as a result, thousands of birds are dying each year. Take action!
Each year the U.S. discharges into the atmosphere:
15 million tons sulfur dioxide:
70% from power plants burning coal or oil.
30% from smelters and refineries.
20 million tons nitrogen oxides:
40% from cars, trucks, planes
30% from power plants
30% from other industrial sources.
For sulfur dioxide, the U.S. is the greatest contributing nation. But the emission rates are increasing so fast in Asia that this region has now replaced Europe and U.S. as the major emitter:
Pollution from forest fires, agricultural waste incineration, and burning of fossil fuels has created an "Asian Brown Cloud," of ash, soot, acids and other harmful airborne particles two miles thick, that cuts the amount of sunlight reaching the earth's surface by 10-15%, cooling the land and water and heating the atmosphere. It is probably changing rainfall patterns from Afghanistan to Sri Lanka, causing flooding in some areas and drought in others, and leading to the premature deaths of millions of people.
Sulfur dioxide and nitrogen oxides combine with water in the air to form sulfuric acid and nitric acid, causing acid rain, which can fall hundreds or thousands of miles from the source. The N.E. part of the U.S., and central Europe are the worst affected.
Sources of sulfur dioxide in the U.S. are concentrated in Ohio, Indiana and Illinois, and prevailing winds carry it to New England and Canada.
Different regions differ in the degree to which the soil and rock can neutralize or buffer the acid precipitation. Limestone has good buffering capacity, but rocks such as granite and quartz, that contain very little calcium carbonate, have very little buffering capacity. Therefore, regions where this form of rock is present are especially sensitive to the effects of acid rain, and lakes in these areas become acidified very quickly. New England, the Rocky Mountains, the Appalachians, much of Canada and Northern Europe are sensitive for this reason.
Sometimes the effects of acid rain are far removed from the source of pollutants; for example, the acid rain over southern Scandinavia has its origins in continental Europe and Great Britain. Scandinavias waters suffer because the local soils cannot buffer the acid as well as soils closer to the sources of pollution. About 50% of the sulphate deposited in Canada is derived from sources in the U.S.
Acid rain destroys plants and animals in several different ways:
Even if this does not kill them directly, it makes them susceptible to infection by bacteria and fungi and to attack by insects.
Forest dieback has therefore been seen in many places. Acid rain is the suspected (but not proven) cause.
Many countries in Europe have seen extensive damage to forests (table) -35% of Europe's total forested area has been damaged. Similar effects are being seen in China, Brazil, Chile and Mexico, as well as the San Bernardino Mountains of Southern California.
Methyl mercury. Once mercury is dissolved by acid, it is converted quickly into methyl mercury, which is highly toxic to wildlife. This is thought to be the reason for catastrophic decline in populations of loons in the eastern U.S.
The 1990 amendments to the Clean Air Act set up a mechanism to reduce sulfur dioxide and nitrogen oxide emissions, with two phases starting in 1995 and 2000. They set up a system of tradable emissions allowances, under which each utility will receive permits to release an amount of sulfur dioxide, with the allowance decreasing each year. If they don't use their allowance they can sell the credits to other utilities. So there is a big financial incentive for reducing emissions, and the program is succeeding in reducing emissions. The Environmental Protection Agency manages these programs.
A study in 1999 showed that some areas in Europe and N.E. North America are beginning to show slight signs of recovery from acid rain damage. Lakes in most areas except Great Britain showed a 1-6% reduction in sulfate during the 1990's.
Nitrogen is added from other sources in addition to rain: mainly agricultural runoff and sewage. Runoff reaches bays and rivers directly during rainy weather, but it also reaches these bodies of water when it seeps into the soil and eventually gets leached out.
Human Alteration of the Global Nitrogen Cycle
Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen
At Rehoboth Bay, Delaware, a major source is runoff is manure from chicken farms. Scallops, oysters, and the eelgrass beds that provided nurseries for crabs and fish have disappeared. Striped bass, white perch and winter flounder are almost gone. In 1987, Virginia, Maryland, Pennsylvania, the District of Columbia and the federal government agreed to reduce the amounts of nitrogen and phosphorous entering the Chesapeake bay by 40 percent by the year 2000, but they are unlikely to meet that goal.
New restrictions on farm water runoff
Nutrient pollution stimulates the growth of algae, and when this happens on a large scale, the algae can use up the oxygen needed by other marine life -a process termed eutrophication. In recent years there have been serious incidents of eutrophication in many of the shallow bays and estuaries along the east coast - Chesapeake Bay, Delaware Bay, New York Bight, Long Island Sound, Narragansett Bay, Florida Keys, Mouth of the Mississippi River.
The Baltic Sea and the Adriatic have also been affected. In the Adriatic in 1989, the bloom was 100 miles long, and the city of Venice was collecting 500 tons of algae per day. Many of the cities around the Mediterranean have no sewage treatment - the city of Athens, for example, pumps all of its waste, untreated, directly into the ocean.
Most kinds of algae are harmless, but when their growth leads to eutrophication this can cause major fish kills (slide shows example from Long Island Sound).
|Many algal blooms can easily be seen from space
because their skeletons are highly reflective, making the water appear milky. The image
shows Coccolithophorid blooms in the Celtic Sea, May 18, 1998. From NASA's
But a few dozen species produce toxic chemicals that can kill other marine life including fish, birds and mammals. The blooms of these kinds of algae (Harmful Algal Blooms) are called red tides or brown tides. The gulf coast of Florida often gets HABs caused by Gymnodinium breve, which produces a toxin called brevitoxin. In 1996 one of these HABs killed 149 manatees.
In the Sea of Cortez in 1996, an
HAB killed 162 dolphins.
In Monterey Bay, CA in 1991, a similar bloom killed hundreds of brown pelicans.
In May 1998 62 California Sea Lions in Monterey Bay suffered seizures and deaths caused by domoic acid toxin from an HAB. The toxin had accumulated in the anchovies and sardines upon which the animals were feeding.
Marine biotoxins suspected for sea lion mass deaths
China fishermen battling ``red tide'' invasion
During HABs, shellfish (especially oysters and clams) living in infested waters take up the toxins and become poisonous to people as well as to animals. Harvesting of shellfish has been banned or restricted in 37% of U. S. waters, because of possible toxicity due to red tides.
In 1997, a new kind of toxic algal bloom started to occur in coastal North Carolina and in the Pokomoke River, Virginia, a tributary of the Chesapeake Bay. This involved a very unusual species called Pfiesteria piscicida (the "cell from hell") that can take on about twenty different forms including some that look like amoeba, some that look like dinoflagellates, some that can remain dormant in mud for long periods, and some that can attack and destroy the flesh of fish, causing open sores that kill the fish. It releases a toxin that is 1,000 times more powerful than cyanide. In 1995 Pfeisteria killed 14 million fish in North Carolina. It also releases an airborne toxin that can cause open sores, nausea, memory loss, fatigue, disorientation, and Alzheimer's disease-like symptoms in fishermen, commercial divers, and marine construction workers who have come into contact with the organism.
Harmful algal blooms, and other cases of eutrophication, are not necessarily a result of pollution caused by humans. However, they have been on the increase in the last few decades. There are more reported toxic species, more known toxins, more areas affected, more fisheries resources affected, and higher economic losses than there were 25 years ago. These blooms often, but not always, occur in areas where the water is unnaturally rich in nutrients, usually from sewage, animal wastes and agricultural runoff rich in fertilizer. For example, runoff from chicken farms and hog farms is thought to have contributed to the 1997 Pfeisteria outbreaks. This leads to speculation that many of them are caused by nutrient pollution, or that the kinds of species found in the blooms are different than previously seen because of the pollution. It is also possible that some kinds of blooms have increased because the species responsible have been spread by human activities, for example transport in ballast water in ships. The Environmental Protection Agency is responsible for setting limits on the amounts of allowable nutrient pollution from both point and non-point sources.
Pfiesteria Outbreaks Demand Eco-System Level Solutions | The Fuss Over Pfiesteria | Pfiesteria No Hysteria
In the mid-1970's, farmers on the west side of California's Central Valley found that their crops were dying of selenium poisoning. This was because the soil is high in selenium and drainage is poor. So they built drainage systems to carry the irrigation wastewater into evaporation ponds. One place where this happened was at Kesterson Reservoir, adjacent to Kesterson National Wildlife Refuge. At the reservoir, the water was simply allowed to evaporate. At first, wildlife officials thought that this plan would be beneficial to wildlife in that it would provide additional waterfowl habitat. In fact, it created a poison trap.
In 1983, biologists began to find several problems at Kesterson. Large numbers of bird eggs failed to hatch, and the embryos showed gross deformities. A flock of tricolored blackbirds showed complete breeding failure -all of their eggs failed to hatch. Eventually, thousands of dead adult birds were found.
After two years of research the state declared that high levels of selenium were responsible for the abnormalities and mortality:
After two years of research the state declared that high levels of selenium were responsible for the abnormalities and mortality:
Selenium levels (ppb):
Selenium is a normal component of soils and in fact is required, in small amounts, for life. But at high levels it is toxic. Cadmium, arsenic, boron, uranium and pesticides also get concentrated and may be contributing to the problem. Detailed reports are available.
The Kesterson problem was solved (actually, postponed) by draining the ponds (into the San Joaquin river) and covering the area with dirt.
In 1989 similar problems showed up at ponds next to the Kern National Wildlife Refuge in the Tulare basin, and the deformity rates were five times as high as at Kesterson. The problem was similar in that the lack of natural wetlands forced the birds to use the contaminated ponds. Similar problems have started showing up at Stillwater National Wildlife Refuge in Nevada, the Kendrick Reclamation Project in Wyoming and the Middle Green River in Utah. Dozens more sites are being investigated.
The Salton Sea in California (pictures from space) is another site suffering from buildup of salts and nutrients, and in this case the ecological consequences are becoming more and more disastrous. Eight million fish died there in a single day in 1999. The Audubon Society reports that the Salton Sea supports 70% of bird species found in California, 34% of breeding species in the state, 90% of eared grebes, 90% of white pelicans, and is the only inland breeding site for the California brown pelican.
One potential solution to the selenium accumulation problem has been devised and experimented with by Dr. Bill Frankenberger at U.C. Riverside. He has isolated strains of fungus that can convert selenium into a non-toxic gas, and developed strains that can carry out this conversion at 200 times the normal rate. Unfortunately, this is illegal because of EPA regulations that restrict the transfer of toxic materials.
Heavy metals may claim Doñana birds, ENN Daily News -- 3/16/99
Oil spills, usually resultiung from tanker accidents, often occur near coasts and therefore have a devastating effect on local wildlife, especially seabirds. Areas of heavy shipping, such as the St. Lawrence River and other estuaries, are especially threatened by these accidents.
In the U.S., the Oil Pollution Act of 1990 came about in response to one of the worst oil spills, the sinking of the Exxon Valdez. The Act created a trust fund available to fund up to one billion dollars per Spill.
Two fifths of world's African penguins threatened by oil spill
In recent years biologists have been observing sporadic die-offs, disease, emaciation and reduced reproductive success among marine mammals. In some cases, a virus is suspected; in other cases, it may be red-tide toxins, and in other cases, the disease and/or deaths may be due to the presence of contaminants that interfere with the function of the immune system. All major classes of pesticides (organochlorines including DDT, organophosphates including malathion, and carbamates including aldicarb), heavy metals, dioxin, and PCBs, are known to affect the immune system. When die-offs have been attributed to viruses and other pathogens, it is suspected that the animals' immune systems may have been compromised by high levels of one or more contaminants, making them abnormally susceptible to disease.
Seals: In 1987-1988 about 20,000 of two species of seals in the Baltic and North Seas died and washed ashore along the coasts of Denmark and the Netherlands. The cause of death was reported to be a new kind of virus called morbillivirus. Seals in the North Sea and nearby waters have been declining for some time. For example, between 1950 and 1975 the seal population in the Wadden Sea dropped from >3000 to 500.
Mediterranean Monk Seals. 81 Mediterranean monk seals were found dead on the beaches of Western Sahara and Mauritania during May and June 1997. These individuals represent about a third of the only remaining true colony of this species (220-300 individuals), inhabiting the Peninsula of Cap Blanc. As of August 1997, it is estimated that 71% of the population has already disappeared. The cause is thought to be a toxic dinoflagellate bloom, but no definitive evidence has been found for this.
Whales: In fall 1987, 15 humpback whales were found dead around Provincetown, Mass. The cause was suspected to be a toxin found in high levels in the mackerel food of these animals, but this explanation has been questioned. There has been a marked increase in sperm whale strandings on the coast of the North Sea. Gray whales have been stranding in record numbers (274 in 1999 and more than 300 in 2000) along the Pacific coast of North America.
Dolphins: In 1987-1988, 2,500 or about half of the Atlantic coast population of coastal bottlenose dolphins washed up dead on beaches from New Jersey to Florida. The cause was also reported to be a morbillivirus, but the infection may have spread so widely because the animals' immune systems were compromised by pollutants; DDT and PCBs were found at high levels in the samples that were analyzed. In other recent samples PCB+PBB levels of 3,200 ppm found in beluga whales and 6,900 ppm in bottle-nosed dolphins. U.S. considers materials containing more than 50 ppm hazardous.
In 1990, at least 250 bottlenose dolphins washed up dead in the Gulf of Mexico. Suspected causes are pesticides, heavy metals, or an epidemic.
162 dolphins were found dead on Gulf of California beaches in 1997. Mexican authorities reported they probably had been killed by red tide toxins.
In 1994, 21 dolphins and three sperm whales washed ashore along the central coast of California
Manatees: In 1996, over 100 West Indian Manatees off the west coast of Florida died, probably due to red tide (Gymnodinium breve) toxins.
Eared Grebes at the Salton Sea. In 1992, 150,000 eared grebes were found dead at Salton Sea, California's largest and most polluted body of water that serves as an agricultural sump for Imperial County. Until a few years ago it was a tourist destination, but this has stopped because of the pollution. The grebes had higher than normal levels of many heavy metals, but probably not high enough to have killed them. In February 1993, 700 of the birds were found dead.
Threats to Florida sea turtles on the rise | Massive die-off of endangered turtles in the Guianas
Another biologically active category of chemical pollutants are the endocrine-disrupting chemicals. These chemicals mimic the effects of the body's own hormones and can impair the immune system as well as sexual development and fertility. Some investigators believe they also cause breast, ovarian and testicular cancer in humans and may account for a 50 percent drop in sperm counts in Europe and North America.
Chemicals in this group include many pesticides (DBCP, DDT, DDE, kepone, heptachlor, chlordane, dieldrin, mirex, lindane and toxaphene), dioxins, PCBs, Bisphenol-A, and phthalates, many of which mimic the female hormone estrogen. Most are long-lived compounds and can bioaccumulate in the environment. In a study of Japanese rivers, lakes and groundwater reported in 1998, eleven suspected endocrine disrupters were found in varying levels at 122 of 130 sites.
Tributyltin is also an endocrine disrupter. It causes female purple snails to develop extra male sex organs, interfering with their fertility. Sterile purple snails are now found along the entire Norwegian coast which is heavily contaminated with TBT.
In a study reported by The Worldwide Fund for Nature, "significant levels" of 16 different phthalates were found in newborn babies. Read about how these chemicals might be affecting human development, and what could be done to alleviate the problem.
Most of us have at least 300 to 500 measurable man-made chemicals in our body tissue, chemicals that wouldn't have been found 50 years ago because they didn't exist. Many of these are present at concentrations a thousand times higher than our body's own chemical messengers. The chemical industry produces about 1000 new chemicals every year.
Our Stolen Future Home
In the 1970s and 1980s in many parts of the world, frogs, toads and other amphibians showed catastrophic declines. The cause is unknown, but suspected to be acid rain or ultraviolet radiation.
The data is mostly anecdotal but very clear. For example the golden toad lives in a 1/2 square mile in Costa Rica's Monteverde Cloud Forest Preserve. At one site 1000 males were found in 1987, but only 1 in 1988 and 1 in 1989.
An Australian Stomach-brooding frog was so common in 1974 that one collector could collect 100 in a single night. By 1980 it had completely disappeared.
In the early 1980's, the Yosemite toad suddenly disappeared from the High Sierra.
Other dramatic declines of amphibians have been reported from Mexico, Brazil, Colorado and Wyoming. Up to one-third of the amphibians native to the United States may be in decline.
The fact that the amphibians are disappearing from protected nature reserves, at the same time in different parts of the world, suggests a single, global cause. Amphibians have survived many global changes during the 100 million years they have been on the earth. They survived the extinction of the dinosaurs and the age of mammals. As David Wake said, "They are tough survivors. If they're checking out now, I think it's significant."
Physiologically, amphibians might be good indicators of environmental problems. Their skin is permeable to airborne gases. They live both on land and in water at different life-cycle stages, and they are high in the food chain so might be susceptible to accumulation of toxic materials from lower in the food chain.
Habitat destruction is causing loss of amphibians in some places, but many of the disappearances are not related to that cause.
Overcollecting, unusually hard frost, dry summers, other kinds of pollution, and predatory fish have been suggested but none of them has been documented.
Acid rain is suggested in many cases. In the Rocky mountains the amphibian eggs are sensitive to the acid water from melting snow in the spring. Spotted salamanders can no longer live in snow-melt ponds in upstate New York because the snow is too acid. The North America wood frog, which is acid-tolerant, is doing better than other North American frogs and toads.
Endosulfan, an organochlorine pesticide, is also suspected of contributing to amphibian declines.
Research published in 1994 suggests that increased ultraviolet radiation caused by stratospheric ozone depletion may be killing frog eggs. Frog species in Oregon that lay their eggs in open sunlight suffered the worst declines, and they found that UV filters improved the survival rate of these eggs under natural conditions. Similarly, the decline in toad populations in Colorado is thought to be the result of ozone depletion.
Deformed frogs have been showing up at very high rates in the northern U.S. Bizarre extra legs, missing legs, and missing eyes are the most common. They were first found by a class of 6-8 graders on a field trip in Minnesota in 1995, but have since been found in six species, at rates up to 60%, at over 100 sites throughout Minnesota, as well as in Vermont, Oregon, Delaware and California. One possible explanation is that the frogs wereexposed to sulfonylurea herbicides. These chemicals have come into widespreaduse in the Upper Midwest in the 1990s. They are extremely potent and are knownto interfere with embryonic development and with thyroid function. The Minnesota New Country School Frog Project has developed a web site to compile information on deformed frogs. More Background.
It is becoming increasingly clear that the earth's climate is warming as a result of the accumulation of "greenhouse gases", notably carbon dioxide. The kinds of data supporting this conclusion are
And apparently in response to this climate change, many species of plants and animals are changing their geographic distributions:
Some species cannot change their range sufficiently, or there is no appropriate habitat within the climatically favorable zone, so they are declining or being adversely affected:
Many more examples are being found. International efforts to reduce greenhouse gas emissions and find other ways to reduce global warming have been hampered by weak support from the U.S. which is the major contributor of greenhouse gases.
Global Temperature Jumps off Chart; from the Worldwatch
Draft Report Affirms Human Influence
Global warming threatens Caribou survival
Avoiding Global Warming
Global Warming Early Warning Signs
Status and Trends - Climate Change
Climate Change Could Cause Major Changes in U.S. Ecosystems
Global climate change poses a serious threat to lakes, streams, rivers, and wetlands throughout the United States
EPAs purpose is to ensure that:
All Americans are protected from significant risks to human health and the environment where they live, learn and work.
National efforts to reduce environmental risk are based on the best available scientific information.
Federal laws protecting human health and the environment are enforced fairly and effectively.
Environmental protection is an integral consideration in U.S. policies concerning natural resources, human health, economic growth, energy, transportation, agriculture, industry, and international trade, and these factors are similarly considered in establishing environmental policy.
All parts of societycommunities, individuals, business, state and local governments, tribal governmentshave access to accurate information sufficient to effectively participate in managing human health and environmental risks.
Environmental protection contributes to making our communities and ecosystems diverse, sustainable and economically productive.
The United States plays a leadership role in working with other nations to protect the global environment.
The EPA's Pesticide Program
The EPA's 1999 Annual Plan
EPA's Strategy for Persistent, Bioaccumulative and Toxic pollutants (PBT) When a company or individual introduces a new chemical or a significant new use of a chemical, they must obtain a permit from the EPA. Candidates for listing in the PBT category are identified by their similarity to known PBTs. They must be tested by conventional toxicity tests as well as by new testing procedures, including tests of:
The EPA plans to develop and implement national action plans to reduce priority PBT
pollutants, of which the first twelve have been identified:
|EPAs First 12
Priority PBT Pollutants
From the Canada- U.S. Binational Toxics Strategy
dioxins & furans
The United Nations is developing international agreements for the control of Persistent Organic Pollutants, including many of the same chemicals that are on the EPA list. President Bush has announced that he intends to sign the first global treaty on toxic chemicals--the Stockholm Convention on Persistent Organic Pollutants (POPs). This is one of four significant international treaties on chemicals in the environment.
At the same time, the agreements of the North American Free Trade Association and the World Trade Organization are encouraging much heavier pesticide use by increasing competition between growers in different countries, reducing food safety inspections, eliminating labeling of eco-friendly products (e.g. shade-grown coffee) and prohibiting regulations that discriminate on the basis of the way products are made.
Noise can be very disruptive to the behavior patterns of animals that are required for their reproduction and survival. One form of extremely loud noise pollution, the experimentalLow Frequency Active Sonar (LFAS) being developed by the U.S. Navy for detection of enemy submarines, is so loud that biologists fear it may not only disorient marine mammals but may also do physical damage to their ear structure. The system generates sounds that can reach 165 decibels at 40 miles from the source, and 140 decibels more than 300 miles away. Several examples of marine mammal strandings have been associated with LFAS and other types of sonar use. Killer-whale biologist Ken Balcomb observed a stranding of a beaked whale in the Bahamas, and obtained evidence for ear damage this animal. He had great difficulty convincing government authorities that this could be caused by naval sonar activities.
The Navy's deployment of LFAS as been challenged in a successful lawsuit by the Natural Resources Defense Council, the Humane Society, the League for Coastal Protection, the Cetacean Society International, and the Ocean Futures Society and its president, Jean-Michel Cousteau. In October 2002, a federal court ruled in favor of the suit. In announcing a preliminary injunction against deployment of the system, U.S. Magistrate Judge Elizabeth LaPorte found that the National Marine Fisheries Service and Navy were likely to have violated several federal statutes, including the Marine Mammal Protection Act (MMPA), the Endangered Species Act (ESA), the National Environmental Policy Act (NEPA), and the Administrative Procedure Act (APA). The court ordered the Navy to meet with the plaintiffs to discuss how the system might be deployed, on a more limited basis, while the lawsuit is pending. Act now!
The general level of background noise in the ocean is also increasing and threatening to disrupt communication between marine mammals.
Some things you can do: Simple Lifestyle Changes