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Effects of DDT

Results of DDT

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Although today we think we know the problem about DDT, there are still problems that need to be solved.  Bad chemicals are still being dumped into the temperate forest and other ecosystems that effect the flora and fauna in that area.  A chemical that are similar to DDT that are still being dumped DDE.  DDE is what is left of the DDT in the environment and unfortunately it stays there for a long time and it is a hard thing to lose in an ecosystem.  Some of its affects on animals is that it can cause thin eggshells and also sterile eggshells which means nothing inside of them (like baby birds).

 

Another short term affect was the decrease in bald eagle population. Like the eagles many other birds were also affected by DDT.  One reason as to why the birds and eagles were affected was because of the many different toxins that flowed into water as a part of runoff.  As we know eagles and some birds feed from the fish that live in fresh water.  But these toxins were trapped in the bodies of if not all most fish in the waters.  Since the eagles and birds eat the fish they too consume the toxins with in the fish.  The transfer/concentrating of toxins throughout the food chain is called Biomagnification.  So the fish were intoxicated as well as the eagles.

The toxins inside the eagles and birds enabled them to do many different things.  The most difficult was to produce offspring.  The different toxins and DDT forced the birds egg shells to become thin, so when the mother laid her eggs and sat on them to keep warm they would crush leaving no baby eagle or bird.  This made it hard for the eagles to continue and make a bigger population.

            One part of the short term affects is that the DDT kills any type of insect that tries to eat/or come in contact with a type of plant with DDT on it.  This harms the entire food chain in this one region of the Temperate forest.  Because it kills the insects it would harm the bird population that rely on these insects for their food.  If these two populations in an area run out then the entire food chain for that community is all messed up.

It was not until the late 1940’s that problems began to occur. Insects began to develop resistance to DDT and it was discovered that it was of high toxicity to fish. DDT has a life of around eight years so animals cannot metabolize the substance rapidly. Since DDT is deposited in fatty tissue, if ingestion occurs at a steady rate, excess DDT can build up within an animal to toxic levels. When DDT is sprayed from planes it can remain on the ground for years. The reason being is DDT hardly evaporates. Eventually DDT mixes with rain water and is evaporated and is re-dispersed through precipitation into nearby rivers and even oceans greatly affecting animal life. DDT can affect and contaminate waters and soil away from where it was applied. Bacteria can convert DDT into even more toxic substances Such as DDD and DDE. Even though people knew about this in the 1940’s it was not dealt with until the 1970’s. DDT over time Can Harm an animal.

           

 Another short term affect that turns into a long term affect is when you spray plants with DDT and it rains, a portion of the DDT that you sprayed onto the plant is than apart of the water cycle resulting in acid rain.  It may run off the plant and into the soil which makes it grow within the plant and it helps the roots feed onto it.  When the soil is polluted with different types of acidity it changes the soil’s pH which means soil organisms are killed since the soil’s pH has changed.

 

A brief history of the case study #2

DDT the first of the chlorinated organic insecticides (“insect poison”) , was originally prepared in 1873, but it was not until 1939 that Paul Muller 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). DDT is an insecticide that is used for killing any malaria or disease carrying insects that come in contact with it. DDT also kills lice that carry typhus. DDT although it is harmful to some animals it is a life saver. The World Health Organization estimates that during the period of its use approximately 25 million lives were saved. DDT seemed to be the ideal insecticide, it is cheap and of relatively low toxicity to mammals. 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. DDT is not metabolized (or digested) very speedily by animals; instead, it is deposited and stored in the fatty tissues. Because it is stored in fatty tissues it takes about eight years for an animal to metabolize half of the amount of DDT it has ingested. Over time this poses a threat if too much is built up in fatty tissue. Scientists warned 25 years that we would se an increase in mosquito-borne killer diseases. West Nile fever is an example.

Steps being taken to alleviate the problem

            From my research I have found that many of the stereotypes of DDT are false.

Many legislative acts have been passed to illegalize DDT. Although since then DDT levels in water have lowered. Many of the “nasty effects” of DDT are greatly exaggerated. However DDT in large amount can cause problems, problems in respiratory, reproductive, and acute poisoning problems. The legislative act to ban DDT was more based on politics and the controversy over the book Silent Spring which distorts and exaggerates facts on DDT than actual scientific fact. A major step to alleviating the problem was the 1973 ban of DDT.

 

 

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Andis Reks, Derek O'Toole, Ian Murphey, Parker Winslow, Ted Amendola