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Environmental Issues Introduction Environment and the dependence of man on the environment become the issue of the day. Many world organizations consider DDT (dichlorodiphenyltrichloroethane) to be one of the most dangerous chemical compounds, while others claim that DDTs harm may overweight possible negative consequences. Yet, it should be taken into consideration that DDT refers to toxins closely associated with cancerous disease, human immune system and reproductive system malfunctions. This substance also imposes a threat to the wildlife; it does harm to the world ecosystems and constitute a menace to flora and fauna.
Many environmental organizations oblige the world countries to stop using DDT and DDT containing substances. Some of these substances were used as insecticides, while the others were used as chemicals in industry, or were the additive products in industrial processes. However, all of them have much in common - all DDT containing substances constitute a menace both to the human health and to our environment; they do not decompose during the long-term period of time, and can be transferred for long distances with water and air flows. The present study explores the controversial issues about DDT and the impact it has on environment, and advances the hypothesis that, despite the fact that DDT may be used for the welfare of mankind (e.
g. to combat malaria, etc), it should be banned worldwide. DDT Better Living Through Chemistry Despite all negative aspects of using DDT, Alexander Gourevitch and some other researchers claim that DDT, the substance related to persistent organic pollutants, in case it is properly used is not as dangerous as people consider it to be and remains the most effective and the cheapest way to combat malaria (Cunningham & Cunningham, 2005). Indeed, it is a common knowledge that malaria is the 'killer number one' for pregnant women and children in African countries. It is one of the most dangerous diseases in Asian and South American regions. As it was already mentioned, DDT is one of the cheapest and the most effective way to combat malaria, as it kills insects (namely, mosquitoes), which spread the disease.
However, some organizations arguing that DDT should be continued to used face difficulties due to various treaties, regulations, and conventions banning pesticide usage (and DDT usage, in particular). Yet, especially after numerous deaths caused by malaria in the third-world countries, it becomes important to find out, whether DDT usage is not as dangerous as one may thought it can be. The supporters of DDT usage claim that atomization of the poisoning particles of chemicals in the air is one of the most effective ways to combat malaria (Easton, 2007). Despite wide range of chemicals able to perform this function, DDT is still considered to be the best chemical approved as safe to be used in homes.
Before DDT was used to combat malaria, this disease caused about 2 - 3 million deaths per year, while the actual number of people suffering from malaria was significantly higher. As it is claimed by Alexander Gourevitch and others, in result of ten years of DDT usage malaria no longer constituted a menace number one in the world countries. For example, according to statistics in India alone malaria rates reduced from 75 million in 1952 to 100, 000 in 1964. UNO and WHO consider that DDT rescued about 50 million of lives (Garrett, 1994).
In 1948 Dr. Muller, whose name is associated with DDT, was awarded the Nobel Prize for his outstanding contribution in medicine. Historically, the campaign against DDT usage originated from 1962, when Rachel Carson has published the book "Silent Spring." Carson dweller about DDT and the impact it has on environment, and accused DDT of mass death of birds (Carson, 1962). Further, the laboratory researches on mice (the experiments, where mice were receiving nutrition with DDT overdoses) have proved that DDT may cause cancerous diseases in mice. The situation was aggravated by the fact that DDT half-value period makes up about eight years, thus making possible for this chemical to accumulate in tissues. These facts were considered to be enough to ban DDT as one of the most dangerous chemicals ever existing.
The ban appeared to be almost global. While UNISEF and WHO undertake attempts to insist of DDT usage, various world agencies and organizations (especially those, who are aimed to assist the third-world countries with high level of poverty, for example, USAID) refuse to appropriate funds to purchase pesticide due to fact that it is banned in these countries. As it is claimed by the researchers, the results were catastrophic. For example, in Sri Lanka, where malaria rates were reduced from 2, 800, 000 cases in 1948 by 17 cases only in 1964, it drastically increased by 2, 500, 000 in 1969 (five years after DDT usage was banned in result of the worldwide campaign) (Garrett, 1994). The situation in African countries was almost the same.
Nowadays, as it is claimed by the researchers, over one million people dies from malaria, and, according to the preliminary data, 30 - 50 million deaths were caused because of DDT ban during the past decades. As it is claimed, DDT is neither cancerous for humans, nor mutagenic agent for fauna. DDT hardly can be conductive to the reduction of birds' population. What concerns the assumption that DDT has negative impact on environment all these cases were reported to be local and can be explained by DDT overdoses. Malathion, chemical that may substitute DDT by its function, is two times more expensive and requires to be used twice as frequent compared to DDT.
Deltamethrin, yet another insecticide is three times more expensive, while the most effective chemical propoxure is twenty-three times more expensive than DDT. Obviously, the third-world countries are unable to overspend their budget in order to combat malaria. DDT Negative Aspects DDT - Facts DDT was widely used throughout the world in 1950 - 1960, both in agriculture and to combat malaria. In 1970 s many world countries gradually stopped using DDT due to its potential impact on wildlife population (Chapin, 1981). Some world countries continue using DDT to combat malaria, although many other countries use more effective chemicals and complexes of methods in order to control this disease. As it was already mentioned, DDT was first synthesized in 1874.
In the late 1930 s Paul Muller made a discovery concerning effective usage of DDT in the capacity of insecticide. DDT then turned out to be so effective in health care and military hygiene (mostly as a disinfectant against lice) that in 1948 Muller was awarded Nobel Prize in the field of medicine and physiology for his discovery. During the World War II DDT was used predominantly to prevent diseases (mainly epidemic (louse-borne) typhus) among the militaries and civil population, as these diseases are transmitted by lice. In result of these preventive measures, the World War II was the first war with an outstanding low number of deaths caused by typhus. During the 1950 - 1960 DDT was widely used to protect agricultural resources (mainly, agricultural fields) from insects (Garrett, 1994). This pesticide appeared to be a real miracle able to combat the infection carriers for such diseases like malaria and encephalitis.
The use of DDT as insecticide against malaria mosquito allowed reducing the mortality rate drastically. At the same time, World Health Organization claimed that DDT may menace a threat to the world society and to our environment. How DDT is used to combat malaria In order to combat malaria, DDT is sprayed over the inner surfaces and walls in buildings, located nearby the areas with maximal concentration of malaria mosquitoes. Naturally, such kind of usage allows DDT entering human organism. Mexican and South African researchers reported high DDT concentrations in blood serum of people, who live in the areas where DDT is used to combat malaria (Garrett, 1994). According to the researchers, DDT level in blood in infants, who were born (and continue to live) in these areas, is significantly higher than so-called 'safe' level recommended by the World Health Organization and UNO guidelines.
The results of these researchers forced scientists to search for alternative safer methods to combat malaria in these countries. Although, as it may seem, DDT spray treatment in the buildings limits the impact pesticide may have on the environment, there are still data confirming that the remainder of DDT migrates into nearby waters. In addition, the cow milk from cows inhabiting in the areas where DDT spray treatment is used to combat malaria, also has the increased DDT concentration. The effectiveness of DDT for malaria Obviously, DDT is effective to combat malaria, in case it is used properly, and in limited quantities. DDT indeed allows saving thousands of lives annually. At the same time, the world countries should take into account potential danger of DDT usage, as well as limitations.
Some experts in World Health Organizations consider DDT use to combat malaria to be an appropriate method, but note that DDT should be used exceptionally in specifically defined situations such as those imposing high or special risk to the population. Pan-American healthcare organizations express doubts concerning the widespread use of DDT and consider that DDT spray treatment is not effective if used as preventive measure (Garrett, 1994). DDT and its impact on environment Despite enthusiasm concerning the effectiveness of DDT to combat malaria, DDT has negative impact on environment. First negative consequences of DDT usage were found in Florida, where the amateur ornithologist, who has been observing the behavior of eagles since 1939, reported the unusual mating behavior and failures in reproduction in eagle generations in 1947 (Stokstad, 2007). The similar effect in seagulls was observed on the other coastal areas of the United States. These violations in reproductive functions in birds were explained by the negative impact of DDT on birds.
In 1980 s the negative impact of DDT and other chlorine-organic pesticides were reported while observing alligators' health inhabiting the Alaska Lake areas. According to the researchers, the samples of male alligators' blood contained half the value of recommended testosterone level. DDT, similar to other persistent organic pollutants, is easily distributed in the water and airflow's throughout the world. It was reported that even Antarctica penguins' blood samples contain some quantity of DDT. Therefore, the use of DDT does constitute a menace to the global environment. Due to broad action spectrum DDT kills both harmful and useful insects.
At the same time, DDT resistance allowed pesticide to accumulate in food chains and had fatal effects on its upper members. The researches proved that DDT has influence on virtually all living organisms. It accumulates in tissues of mammals and acts as carcinogen, mutagen; DDT has embryo toxic, neurotoxic, and immune toxic action, changes hormone system and causes anemia, and inflammations of the liver. DDT has negative impact on birds, as it causes eggshell thinning, and has negative influence on fishes, birds, snakes, and animals. According to the research aimed to examine ecosystem in Michigan Lake, the gradation of DDT accumulation in food chain was as follows: in the lake silt 0. 014 mg / kg , in crustaceans 0. 41 mg / kg , in fishes 3 - 6 mg / kg , and, finally, in adipose tissue of the seagulls living on these fishes over 200 mg / kg (Garrett, 1994). Rachel Carson provided several samples of a simple food chain with DDT inclusion.
For example, it was supposed that DDT was used to combat the fungus Ceratocystis ulm causing Dutch elm disease. The remainder of DDT from the trees was absorbed with the rainwater by the soil. Then, DDT was consumed by earthworms. As colley's and robins live mainly on earthworms, DDT was consumed with the earthworms by the birds.
DDT does not necessarily leads to death, but rather influences the birds reproduction process; therefore, the birds either become sterile, or produce infertile eggs (Carson, 1962). In some cases DDT causes death in the nestlings, especially if they are fed with the earthworms. In such a way, the attempt to combat Dutch elm disease made robins the endangered species. Conclusion So, does DDT pose a threat to people?
DDT and its decomposition products are classified as potentially canc erogenic substances. According to the researches, DDT results in development disorders, and may influence reproductive function. DDT can be found in human adipose tissue, and in feeding mother's milk. Apart from that, DDT can enter circulatory system. For example, it was found that the DDT level in feeding mother's milk (in U. S.
females) is four times higher than it is allowed by healthcare standards (Chapin, 1981). There is enough evidence of hazards to human health and to the wildlife to justify the necessity to complete ban all over the world. The chemical DDT has been associated with the decline of various species. The soil in the orchid still contains forty percent of DDT that had been used on it twenty years ago. The chemical, which was sprayed in a South African soil, can end up in the fat tissue of Arctic animals. Nowadays DDT is banned in 34 world countries, including New Zealand, CIS countries, Hungary, Denmark, Finland, and many other countries.
However, DDT still remains the subject of heated debates. The proponents of DDT usage assert that that DDT, if properly used, should not be banned. According to them, DDT is the most effective and the cheapest way to combat malaria. There are countries that continue to use this insecticide and consider it to be the panacea. However, it should be taken into account that DDT has negative impact on our environment. In addition, it is not the only method that allows combating malaria and other diseases.
Instead of using it the countries should better develop alternative, more effective methods to combat malaria. Millions of tones of this highly toxic chemical used in the past still can be found in the soil and consistently spread throughout our environment, constituting a menace not only to the countries where it was used, but to the other world countries as well. Therefore, DDT it is indeed so dangerous that it should obviously be banned all over the world. References Carson, R. (1962). Silent Spring.
Boston. Boston: Houghton Mifflin. Chapin, G. (1981). Agricultural production and malaria resurgence in Central America and India. Nature, 293, 181 - 185.
Cunningham, W. P. , & Cunningham, M. A. (2005). Principles of Environmental Science. McGraw-Hill. Easton, T.
A. (2007). Taking Sides: Clashing Views on Environmental Issues, Expanded (Taking Sides: Clashing Views on Controversial Environmental Issues). McGraw-Hill. Garrett, L. (1994).
The Coming Plague: Newly Emerging Diseases in a World Out of Balance. United Kingdom: Penguin Books. Stokstad, E. (2007). Can the Bald Eagle Still Soar After It Is Delisted. Science (316), 1689 - 1690.
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