Pollution
Crops flourish in a silent season,
and pelican mothers weep noiselessly,
waiting at the bus stop with raw throats--they weep for dodo birds
and progeny lost
as we, a prolific species, sit down to the neverending feast.
Pollutants are harmful chemical or physical substances released into the atmosphere, a water source, the soil or a component of the biosphere. When a new chemical compound is developed and produced in large amounts for commercial or medical purposes, immediate benefits to mankind often result. However, side effects that may not be evident for years or even decades after their introduction may be unfortunate consequences. These side effects may alter human behavior or physiology, but more often their adverse effects are first detected by disruption of a component in the ecosystem. One species will be primarily affected, and this will have a domino effect on many others, up and down the food chain. As a result, massive death of many organismal types, from microorganisms to large plants and animals will occur. In this essay I cite a few well-documented examples out of thousands of similar cases where pollution has had a dramatic effect on our lives and our planet.
"They're so small you can't see Ôem,
But when you wheeze and sneeze, it may be Ôem."
The results of a recent UCLA-USC-based study, published in the journal, Environmental Health Perspectives, showed that microscopic airborne particles disrupt cellular processes, harming the human body. These particles are normally present in dust and smoke, but they are most prevalent in the exhaust that results from the burning of fossil fuels. They are so small, that over 10,000 can fit on the head of a pin! Because of their inert nature, they can bypass the body's normal defense mechanisms.
These particles not only penetrate the lungs and bloodstream, they are also found deep inside the cellular organelles of our body tissues, causing oxidative stress and damage, for example, to the powerhouse of the cell, the mitochondrion. The presence of these particles shortens life span and leads to common pathologies such as cancer and heart failure. In less dramatic cases, they reduced lung function. Their presence is believed to be responsible for cases of asthma in hundreds of thousands of people in the LA area alone.
Associated respiratory problems have led to school absences and hospital admissions. In fact, the Los Angeles basin proved to be one of the worst places in the nation for particle pollution. However, throughout U.S. urban communities where traffic and industry are prevalent, the consequences of particle pollution have been documented. It seems clear that a major fraction of the U.S. population suffers some adverse consequence of particle pollution.
"Lacewings and ladybirds, mind where you roam,
The plants are all poisoned that once were your home.
They've spliced in a toxin to kill off the pests.
Now friendly bug-eaters will die like the rest."
The bodies of Americans carry an array of toxins derived from plastics, cosmetics, food additives, and even pesticides banned decades ago. Importantly, fetuses, infants and young children contain much higher levels than do adults. Researchers believe that these pollutants can permanently alter a child's intelligence, memory, motor skills, behavior, and immune system. Organophosphate pesticides, for example, present in bug bombs and lawn sprays, have been shown to cause abnormal brain development, and many of these compounds are present in children's brains at more than twice the levels found in adults! Since children eat, drink and breathe three times as much as adults on a weight basis, these statistics are not entirely unexpected.
Although DDT was banned for use as a pesticide back in the 1970s, it can still be found in the bodies of American children. This long-lasting compound remains unaltered for decades in the soil, from which it can be accumulated by plants, and then concentrated by grazing animals. Since DDT and other poisons have been found to increase the incidence of cancer in adults, the danger to young children may be of major concern.
The problem of chemical pollution has recently been elevated to a new level of concern as a result of genetic engineering. Genetically modified plant crops are already being used to provide food for the burgeoning human population, currently increasing at the incredible rate of 250,000 people per day. To counteract the costly effects of pests on crops, genes encoding pesticides have been introduced. At a recent meeting of entomologists, it was noted that some genetically engineered crops exude 10-20 times the amounts of toxins contained in conventional bug sprays. These chemicals kill beneficial insects such as bees and ladybugs and inhibit the growth of beneficial soil microorganisms, such as those that provide natural nitrogen fertilizer by fixing nitrogen in root nodules of alfalfa, peas and beans. Finally, these toxic agents harm the insect-eating birds that were the traditional sources of pest control before mankind decided to "improve" upon Nature.
Some environmental chemicals have been shown to mimic the normal hormonal responses of the human body, causing suppressed immunity, inhibited brain development and feminization of boys. Comparable effects have been documented in wild animal populations. It seems likely that such chemicals will prove to affect a major part of the biosphere upon which we depend. The prospects are ominous to say the least.
"A wondrous bird is the pelican,
His beak holds more than his belican.
He can take in his beak,
Enough food for a week!
I'll be damned if I know how the helican!"
Dixon L. Merritt
I remember as a boy watching the spectacular California pelicans dive for fish, marveling at their remarkable eyesight and skill. In fact, these pelicans provided our family with endless amusement as we watched the ever-changing show they would put on for us. Then in the early 1970s, these remarkable birds disappeared. For years not a single pelican was sighted in the Monterey Bay. At first, we had no idea why.
The brown pelican breeds in large colonies in a few choice locations on the Channel Islands in Southern California, along the Baja peninsula and in the Gulf of California, Mexico. During the summer months, they fly northward from their breeding grounds as far as Vancouver, Canada. These impressive birds, with silvery coloration, massive bills and unparalleled throat pouches, are the only species of pelican that dives frequently for its prey. Its primary source of nutrition is small surface schooling fish such as anchovies and sardines.
Because the species nests in large colonies on small-island breeding sites called rookeries, the brown pelican has in the past been the target of egg hunters who raided the rookeries by boat. They were also hunted throughout the 19th and 20th centuries for their feathers. Still worse, fishermen who erroneously thought them to be competitors for commercially valuable fish slaughtered thousands. As a result, by 1970, brown pelican populations along the coast had been reduced to less than 20% of their normal numbers.
Losses due to exploitation were dwarfed by the dramatic tragedy that befell these birds during the early 1970s when they essentially disappeared from the California coast. Pesticides such as DDT and endrin were then used to kill mosquitoes and other insects, and unknown to those of us who used DDT, it interferes with the process of calcium deposition, necessary for the formation of egg shells. Pelican eggs became too thin and brittle to allow the parents to successfully incubate their clutch.
The disappearance of the California pelican was researched, revealing that DDT runoff into streams that emptied into the oceans was responsible. Pesticide "biomagnification" resulted because non-lethal doses are ingested and concentrated by the fish that the pelicans consume. Many birds died due to the accumulation of lethal doses, but the problem of eggshell thinning resulted in almost complete reproductive failure. On Anacapa Island off the California coast, in one year, only a single fledgling survived out of 552 nesting pairs. The number of pairs at this site had exceeded 10,000 prior to human exploitation and the use of DDT.
In 1972, the cause of the tremendous reduction in the pelican population became recognized, and DDT as well as other related pesticides were banned by the U.S. Environmental Protection Agency. Gradually the brown pelican, which had remained viable off the Baja coast, returned to California. Since then, numbers have significantly increased, and with the help of naturalists, old breeding and nesting sites have been recovered. In 1997, about 4,000 breeding pairs on West Anacapa Island were identified. The crisis induced by DDT was over for the pelican, but the full extent of damage to these and many other species will never be fully comprehended.
Atrazine and Frogs
"Frog, he goes a wooin',
But she says: no cooin', nothing doin'."
Atrazine is a stable chemical herbicide used in countries that produce corn. In the U.S., atrazine is the most widely used weed killer. The production and sale of this one compound results in multibillion-dollar profits for the herbicide industry. This compound has been detected in the oceans and fresh waters of countries distant from those that use it, showing that it is stable enough to circle the globe. It exerts measurable effects on wildlife virtually everywhere on Earth.
Recent studies conducted in the laboratory of Tyrone Hayes at the University of California, Berkeley, linked the presence of very low levels of atrazine to developmental abnormalities in both experimental and wild populations of frogs. Specifically, Hayes' studies showed that the compound turns nearly half of the exposed male frogs into transsexual hermaphrodites. Some male frogs develop multiple sex organs, while others have both ovaries and testes, a characteristic of the hermaphrodite. A majority of exposed frogs also showed shrunken larynxes, a crippling handicap for a frog wishing to call to and then mate a female. It is probable that these effects are at least in part responsible for the huge decline in amphibian populations worldwide.
History tells us that research conducted by scientists who are paid to get a specific answer is not likely to be reliable. For example, the tobacco industry conducted research "proving" that smoking cigarettes is not harmful to human health. As we all know, however, extensive research conducted by impartial workers has revealed that it is so harmful that it cuts an average of 20 years off a person's life! Thus, although Hayes' conclusions have been challenged in studies funded by the major producer of atrazine, Syngenta, the results of Hayes' challengers can probably be discounted.
The amounts of atrazine that cause measurable effects on frog sexuality proved to be more than 30-fold lower than the "safe level" amount set by the Environmental Protection Agency for our drinking water. Could the compound also affect humans? Possible effects on human sexuality and fertility should be considered. Dramatic decreases in human male fertility in the U.S. over the past few decades are well documented. Moreover, puzzling rises in premature human birth over the past 20 years is also documented. Is there a connection with atrazine? One study revealed that male workers at a Louisiana plant where atrazine is made exhibited incidents of prostate cancer nearly 10 times that observed for the average male Louisianan.
In light of these findings and possibilities, one might assume that the use of this herbicide would be strictly prohibited. In fact, this is the case in most European countries. However, in the U.S. and most third world countries, no such regulation is in effect. The levels of atrazine worldwide continue to increase at an alarming rate.
Agriculture and Coral
"A fish who seeks a reef,
In brief, is in for grief."
Coral reefs are the major breeding grounds for innumerable species of fish and shellfish. As the human population has grown, first with the advent of agriculture, and later with the industrial revolution, the balance of nature in the oceans has been upset and then largely destroyed. At the end of the 20th century, it was conservatively estimated that one-third of the world's coral reefs are dead, over one-third are sick and dying, and less than one-third remain healthy. This fact accounts only in part for declines in commercially important marine fish populations, which have been reduced to only a few percent of their pre-exploitation levels. One-third of all still surviving fish species worldwide are endangered. This is the largest percentage for any one type of animals.
Many studies have focused on the destruction of our coral reefs, leading to the conclusion that there are multiple causes. First, rising temperatures lead to "bleaching" which can result in coral death. Second, increasing concentrations of atmospheric CO2 make the carbonate chemistry of the oceans less favorable for calcification, an essential process for coral development. Third, bacterial and viral pathogens have been identified as primary causes of coral polyp death, but susceptibility to these microbial diseases may result secondarily from severe weakening of the organisms' defenses.
Recent studies have shown that a fourth major source of coral instability is related to agricultural practices that have been developed and expanded over the past couple of centuries. This conclusion does not target a specific pesticide or fertilizer, although these may contribute to the demise of the coral building polyps. Instead, it appears that increased sedimentation of particulate matter from continental material is a primary cause. Extensive use of agriculture accompanied by alternating periods of drought and heavy rainfall promote erosion that results in the periodic transportation of vast amounts of soil to the oceans. This sediment poses a hazard to reef building corals, first by decreasing access to light and second by interfering with normal feeding practices.
To document the importance of agricultural sedimentation, McCulloch and his coworkers developed methods for measuring the history of sedimentation on Australia's Great Barrier Reef. The results showed that sedimentation increased dramatically following European settlement and agricultural expansion in northeastern Australia.
Corals preserve the history of terrestrial sediment delivery as they build their skeletons of calcium and carbonate because they accidentally incorporate traces of other elements, depending on availability. Suspended sediments from river water, for example, contain barium, a calcium analogue. This gets incorporated into the long lasting coral skeleton in proportion to its concentration in the seawater. Since the skeletons grow at a rate of less than one inch per year, conditions over the ages can be determined and dated for the coral skeletal matter, just as the contents of the rings of a redwood tree can be used to estimate events that took place in its environment over the duration of its long life. Happily, however, a large mass of coral need not be destroyed in order to conduct the experiment.
Detailed studies have allowed quantitation of the amounts and types of sedimentation from 1750 to the present. Sediment levels increased dramatically, about 10-fold, after 1870, shortly following European settlement when both average and maximal barium levels increased. Domestic grazing and land clearance were considered to be the main culprits, increasing erosion. The use of independent research methods allowed confirmation of these conclusions.
The results of these long-term studies in Australia's Great Barrier Reef have been generalized to many other parts of the world. For example, in East Africa, the study of marine corals revealed a similar story of erosion prompted by colonial agricultural practices during the early 20th century. We therefore know that sedimentation has influenced the health and distribution of coral species worldwide.
Global warming is believed to increase the erratic nature of seasonal climate change. This means that erosion, marine sedimentation, and the consequent loss of healthy coral polyp life are likely to increase as human-produced greenhouse gases accumulate. The tragedy of man-promoted coral destruction thus provides one more example of how we are inadvertently disturbing the balance of nature through seemingly harmless activities meant only to sustain the human population.
Taken together we see that almost every aspect of man's activities, our agricultural practices, the burning of fossil fuels, destruction of the forests and wetlands, hunting and fishing, the use of chemicals that alter the balance of nature, the use of medicines that alleviate suffering and prolong life, all add to the global levels of pollution, endangering our delicate biosphere and altering the physiology and behavior of our own species. To me, it seems clear, that none of these problems can be truly solved until we have dealt with the primary cause: a tremendously excessive human population. If we can find a rational solution to this problem, then the human race has a chance for long-term survival. If not, we will undoubtedly learn the hard way: through suffering, death and devastation.
Further Reading
Li, N., Sioutas, C., Cho, A., Schmitz, D., Misra, C., Sempf, J., Wang, M., Oberley, T., Froines, J., and Nel, A. (2003). Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage. Environ. Health Perspect. 111, 455-460.
Calle, E.E., Frumkin, H., Henley, S.J., Savitz, D.A., and Thun, M.J. (2002). Organochlorines and breast cancer risk. CA Cancer J. Clin. 52, 301-309.
Frumkin, H. (2001). Beyond toxicity: human health and the natural environment. Am. J. Prev. Med. 20, 234-240.
Frumkin, H. (2002). Urban sprawl and public health. Public Health Rep. 117, 201-217.
Frumkin, H., and Thun, M.J. (2001). Arsenic. CA Cancer J. Clin. 51, 254-262.
Baldridge, A. (1973). The status of the Brown Pelican in the Monterey region of California: past and present. Western Birds 4, 93-100.
Elliott, A. (1992). Family Pelecanidae (Pelicans) in del Hoyo, J., Elliott, A., and Sargatal, J., eds. Handbook of the Birds of the World, vol. 1, Lynx Edicions, Barcelona.
Hayes, T., Haston, K., Tsui, M., Hoang, A., Haeffele, C., and Vonk, A. (2002). Feminization of male frogs in the wild. Nature 419, 895-896.
Renner, R. (2002). Conflict brewing over herbicide's link to frog deformities. Science 298, 938-939.
Royte, E. (2003). Transsexual frogs. Discover, February, 46-53.
Cole, J. (2003). Dishing the dirt on coral reefs. Nature 421, 705-706.
McCulloch, M., Fallon, S., Wyndham, T., Hendy, E., Lough, J., and Barnes, D. (2003). Coral record of increased sediment flux to the inner Great Barrier Reef since European settlement. Nature 421, 727-728.