what is the problem with DDT?

Answer 1

DDT the first of the chlorinated organic insecticides, was originally prepared in 1873, but it was not until 1939 that Paul Muller of Geigy Pharmaceutical in Switzerland discovered the effectiveness of DDT as an insecticide he was awarded the Nobel Prize in medicine and physiology in 1948 for this discovery).

The use of DDT increased enormously on a worldwide basis after World War II, primarily because of its effectiveness against the mosquito that spreads malaria and lice that carry typhus. The World Health Organization estimates that during the period of its use approximately 25 million lives were saved. DDT seemed to be the ideal insecticideit is cheap and of relatively low toxicity to mammals (oral LD50 is 300 to 500 mg/kg). However, problems related to extensive use of DDT began to appear in the late 1940s. Many species of insects developed resistance to DDT, and DDT was also discovered to have a high toxicity toward fish.

The chemical stability of DDT and its fat solubility compounded the problem. DDT is not metabolized very rapidly by animals; instead, it is deposited and stored in the fatty tissues. The biological half-life of DDT is about eight years; that is, it takes about eight years for an animal to metabolize half of the amount it assimilates. If ingestion continues at a steady rate, DDT builds up within the animal over time.

The use of DDT was banned in the United States in 1973, although it is still in use in some other parts of the world. The buildup of DDT in natural waters is a reversible process: the EPA reported a 90% reduction of DDT in Lake Michigan fish by 1978 as a result of the ban.

Answer 2

I suggest you read the World Health study on ddt. They have given it a clean bill of health,to be used in confined spaces. (www.who.int/mediacentre/news/release/2006/pr50/en/ )All this ddt rejection came from the hippies backin the 70's without any study. One of the problems was it showed up in eagle eggs. The found out later that the eggs which contained DDT had a higher birth rate that the ones without it

Answer 3

DDT is an extremely effective pesticide, and is often cited as a primary factor in the huge reduction of malaria cases worldwide in the 60s. Unfortunately, it is a very persistent pollutant whose breakdown products are also toxic. When it was used in the wild, it accumulated in the tissues of predators (particularly birds) that consumed prey that had fed on DDT-treated grain. It is suspected that DDT is responsible for the decline of bald eagle populations in the 70s.

Answer 4

In 1962, Silent Spring by American biologist Rachel Carson was published. Silent Spring catalogued the environmental impacts of the indiscriminate spraying of pesticides—most notably DDT—in the US. The book questioned the logic of releasing large amounts of these chemicals into the environment without fully understanding their effects on ecology and human health. The book suggested that DDT and other pesticides may cause cancer.[2] The book resulted in a large public outcry that eventually led to DDT being banned in the US, and its publication was one of the signature events in the birth of the environmental movement. DDT was subsequently banned for agricultural use worldwide, but its use in disease vector control continues to this day in some parts of the world.

Answer 5

DDT has been know to cause cancer and kill such small animals as fish and birds. The birds injest it and it get in there system, and when they lay eggs, the chemical eats at the shell and doent allow it to form a proper hard nutrient shell so the bird population decreased. Its also very hard to process out of the body and environment. Even though it was used back in the 60's traces have been found in bird today.

Answer 6

Verbatim from Wikipedia:

DDT is a persistent organic pollutant with a half life of between 2-15 years, and is immobile in most soils. Its half life is 56 days in lake water and approximately 28 days in river water. Routes of loss and degradation include runoff, volatilization, photolysis and biodegradation (aerobic and anaerobic). These processes generally occur slowly. Breakdown products in the soil environment are DDE (1,1-dichloro-2,2-bis(p-dichlorodiphenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane), which are also highly persistent and have similar chemical and physical properties. These products together are known as total DDT.

DDT and its metabolic products DDE and DDD magnify through the food chain, with apex predators such as raptors having a higher concentration of the chemicals (stored mainly in body fat) than other animals sharing the same environment. In the United States, human blood and fat tissue samples collected in the early 1970s showed detectable levels in all samples. A later study of blood samples collected in the later half of the 1970s (after the U.S. DDT ban) showed that blood levels were declining further, but DDT or metabolites were still seen in a very high proportion of the samples. Biomonitoring conducted by the CDC as recently as 2002 shows that more than half of subjects tested had detectable levels of DDT or metabolites in their blood, and of the 700+ milk samples tested by the USDA in 2005, 85% had detectable levels of DDE.

DDT is a toxicant across a certain range of phyla. In particular, DDT has been cited as a major reason for the decline of the bald eagle in the 1950s and 1960s as well as the peregrine falcon. DDT and its breakdown products are toxic to embryos and can disrupt calcium absorption thereby impairing egg-shell quality. Studies in the 1960s and 1970s failed to find a mechanism for the hypothesized thinning, however more recent studies in the 1990s and 2000s have laid the blame at the feet of DDE, but not all experts accept those claims. Some studies have shown that although DDE levels have fallen dramatically that eggshell thinness remains 10–12 percent thinner than pre-DDT thicknesses. In general, however, DDT in small quantities has very little effect on birds; its primary metabolite, DDE, has a much greater effect. DDT is also highly toxic to aquatic life, including crayfish, daphnids, sea shrimp and many species of fish. DDT may be moderately toxic to some amphibian species, especially in the larval stages. In addition to acute toxic effects, DDT may bioaccumulate significantly in fish and other aquatic species, leading to long-term exposure to high concentrations.

Answer 7

DDT is a persistent organic pollutant with a half life of between 2-15 years, and is immobile in most soils. Its half life is 56 days in lake water and approximately 28 days in river water. Routes of loss and degradation include runoff, volatilization, photolysis and biodegradation (aerobic and anaerobic). These processes generally occur slowly.
DDT is classified as "moderately toxic" by the US National Toxicological Program and "moderately hazardous" by WHO .It is not considered to be highly toxic, and in fact it has been applied directly to clothes or used in soap.Indeed, DDT has on rare occasions been administered orally as a treatment for barbiturate poisoning.The EPA, in 1987 , classified DDT as class B2, a probable human carcinogen DDT, like many other organochlorines, has been shown to have weak xenoestrogenic activity; meaning it is chemically similar enough to estrogen to trigger hormonal responses in contaminated animals. This hormonal-mimicking activity has been observed when DDT is used in laboratory studies involving mice and rats as test subjects, and available epidemiological evidence indicates that these effects may be occurring in humans as a result of DDT exposure.

Answer 8

DDT causes birds to lay "weaker" eggs. These eggs would break during incubation, leading to a decline in predatory birds which had higher concentrations of DDT due to being higher on the food chain.

Answer 9

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Answer 10

its basically useless because all the bacteria it was supposed to kill are resistant to it because it was used so often, it selected for the bacteria that were resistant to it, they multiplied and now you have a bunch of resistant bacteria.