Long term effect of DDT?

     In Tzaneen, Limpopo Province, South Africa a study was conducted to find if the males sperm count was effected by the environmental expouser of DDT. There conclusion did not find a positive effect of DDT. My question to the researcher is regarding the results they published. So, what is the normal semen count in a male? Does it matter the age of the person? Did they compare this to other village or to other people in the same village who were not exposed to DDT. Using World Health Organization criteria may not be a good thing, because they are lumping everybody in there pool. They need to do more soil sampling to find if there are any presence of DDT in the soil
 around the village.









Reference:

The long-term effects of DDT exposure on semen, fertility, and sexual function of malaria vector-control workers in Limpopo Province, South Africa.

Dalvie MA, Myers JE, Thompson ML, Robins TG, Dyer S, Riebow J, Molekwa J, Jeebhay M, Millar R, Kruger P.

Source

Occupational and Environmental Health Research Unit, School of Public Health and Family Medicine, Medical School, University of Cape Town, Anzio Road, Observatory, 7925 Cape Town, South Africa. aqiel@cormack.uct.ac.za

Environ Res. 2004 Sep;96(1):1-8.

Shoud we still use DDT?

Combating Malaria with DDT.
     There have been many studies conducted across African Continent that has provided tons of data.
Yes, DDT is harmful to human. Can we find a way to distribute DDT across houses or fields without harming people? Yes, if we can travel past moon, find quark particles, see inside human DNA then why can't we come up with a solution. The reason we are so slow about this is because this is affecting poor countries with very limited resources and there is no incentive.  People are dying everyday from many other diseases and malnutrition.





Reference:

Should DDT Be Used to Combat Malaria?

DDT should be used "with caution" in combating malaria, a panel of scientists reported today

By Marla Cone and Environmental Health News  May 4, 2009, Scientific American

East Greenland polar bears

     After reading this review it shows that the redisugal or the left over of the DDT chemical stays in the tissues of polar bear.  Hopefully the research will continue and we will know the longer term effect. Could these polar bears have ingested the DDT chemical from the fish?


Reference:
Dietz R, Riget FF, Sonne C et al. 2012 Three decades (1983-2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 1: Legacy organochlorine contaminants.Environment International. Ahead of print. doi: 10.1016/j.envint.2012.09.004.

 

Countries that still use DDT.

     In 2001at the  Stockholm Convention Center a United Nations treaty was signed by 100 countries to ban the usage of 12 toxic pesticide chemicals including DDT.

     Since then Ethiopia, South Africa, India, Mauritius, Mayanmar, Yemen, Uganda, Mozambique, Swaziland, Zimbabwe, North Korea, Eritrea, Gambia, Naminbia and Zambia notified the treaty's secretariat that they are using DDT. Also China reportedly has started to use DDT.

     According to World Health Organization, Malaria is one of the world's most deadly diseases. About 880,000 people, mostly children in Sub-Saharan Africa, are killed. DDT has been the most effective assassin of the mosquitoes but it is not always successful. There has been no one vector that can control or kill mosquitoes.

Balancing Act

     I believe there is a way we can use DDT and the population will still be safe. The first thing we can do instead of spraying DDT in the houses is we can paint the outside of the houses, including the doors and screens. That way mosquitoes won't be able to enter. In doing this, we will protect the residents and the person who is spraying. By painting, there will not be any loose molecules in the air which will be inhaled. Here's the kicker, painting will cost more than spraying because it will require more materials and more labor. The brush and containers most be disposed of properly. They cannot be washed because they will then contaminate the water supply. Poor nations will not be able to afford painting therefore they use the alternative spraying method. That is why it is called a balancing act.

Reference
By Marla Cone and Environmental Health News.
This article originally ran at EHN, a news source published by Environmental Health Sciences, a nonprofit media company.

Past Present and Future use of DDT

     Agricultural pests controlled by DDT:
          various potato beetles
          coddling moth (which attacks apples)
          corn earworm
          cotton bollworm
          tobacco budworms
          colorado potato beetles
          gypsy moth.....

it also has been very effective against lice, fleas, mosquitoes, yellow fever and malaria.

Some times we have to weigh the dire effects of DDT to humans and the environment compared to the benefits of eradication of dangerous diseases.  The benefits of spraying DDT on the crops was to eliminate pests.  We have to balance risks and benefits.

     In 1972 EPA banned DDT but we are still manufacturing DDT for other countries.

Reference
     *    toxipedia DDT updated Jan 10, 2011 by Steven Gilbert

Beginning of DDT

     First synthesized in 1874 by Austrian chemist Othmar Zeidler (1) as an insecticidal property to control insect vectors of typhus. Dr. Paul Hermann Muller was awarded a Noble Prize in 1948 for Physiology and Medicine for his effort.  During World War II  DDT was extensively sprayed to control insect vectors of typhus, malaria and dungue fever in Europe and South Pacific. Later back in North America DDT was available to farmers to spray in their fields for many years. Yet, DDT was a very effective chemical against various insects in many countries, but less effective in tropical regions due to the continuous life cycle of mosquitoes and poor infrastructure. Rich countries with big cities were able to spray often but poor countries were not able to spray and gain the benefits of DDT.

References

1. ^ A birth year of 1859 would make him a mere 14 years old at the time of his dissertation in 1873. The 1859 birth yearwas used by Joseph S. Fruton, in his Contrasts in scientific style: research groups in the chemical and biochemical sciences, Memoirs of the American Philosophical Society, Vol 191, 1990, page 373, as well as by Gerhard Oberkofler inLeopold Ruzicka, 1887-1976: schweizer Chemiker und Humanist aus Altösterreich‎ - Page 44. The latter even has him quit his pharmacy studies at the Vienna University in 1872 (at the apparent age of 12/13) to move to Strassburg.

• History | CDC Malaria at www.cdc.gov

• Othmar Zeidler (1874). "Verbindungen von Chloral mit Brom- und Chlorbenzol". Berichte der deutschen chemischen Gesellschaft 7 (2): 1180–1181. doi:10.1002/cber.18740070278

       

What is DDT

     According to Encyclopedia Britannica: "DDT abbreviation of dichlorodiphenyltrichloroethane, also called 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, a synthetic insecticide belonging to the family of organic halogen compounds, highly toxic toward a wide variety of insects as a contact poison that apparently exerts its effect by disorganizing the nervous system".

DDT chemical formula is C14H9Cl5