The Occurrence, Fate, and Impact of DDT Albert Baramuli March 31 st, 2006

History 4,4'-(2,2,2-trichloroethane -1,1- diyl)bis(chlorobenzene) or dichloro-diphenyl- trichloroethane DDT was first synthesized in 1873 by Othmar Ziedler. In 1939, Paul Hermann Müllerr, a Swiss chemist discovered the insecticidal properties of DDT. DDT was developed as the first of the modern insecticides early in World War II. (~ 1945) Between , World Health Assembly adopted a Global Malaria Eradication Campaign.

History By 1967, Malaria was eradicated in most developed countries and many subtropical Asian and Latin American countries. In 1962, American biologist Rachel Carson published the book Silent Spring. Sweden banned DDT in 1970, the USA in 1972, and the UK in In 2001, Stockholm Convention proposed a global ban on DDT and 11 other organic pollutants, effective starting May 2004.

Facts about DDT Technical Grade DDT contains (65-80%) p,p’-DDT, (15-21%) o,p’-DDT, (~4%) p,p’-DDD In environment, DDT breaks down to p,p’-DDE Half life of DDT : ~ 2 days in air, 2 – 15 yrs in soil Degradation by sunlight in air, by microorganism in soil. DDT, and especially DDE, build up in plants and in fatty tissues of fish, birds, and other animals (i.e. bioaccumulation)

Health Effects Toxic Effects - Animal : carcinogenic - Human: relatively safe Neurobehaviour - Poisoning : headache, tremor, fatigue, etc. - Occupational Exposure : Reduced verbal attn., visuomotor speed, and sequencing Cancer - Breast, Pancreatic, Liver, Prostate, Testicular, Endometrial. - Lymphoma, Myeloma

Health Effects Reproductive Health - Semen volume & quality, testosterone amount, sperm DNA damage - Reduce probability of pregnancy - Spontaneous abortion - Birth defects - Shorter lactation period Infant and Child Growth - Height - Mental and psychomotor development DNA Damage - Raised IgA and reduced IgG - Necrosis

Source of Exposure How might I be exposed to DDT ? Eating contaminated foods, such as root and leafy vegetable, fatty meat, fish, and poultry. Eating contaminated imported foods from countries that still allow the use of DDT to control pests. Breathing contaminated air or drinking contaminated water near waste sites and landfills that may contain higher levels of these chemicals. Infants fed on breast milk from mothers who have been exposed. Breathing or swallowing soil particles near waste sites or landfills that contain these chemicals.

Malaria in Africa Efficiency of DDT vector control depends on: Coverage of spraying Mosquito Species Resistance to DDT Climate (rainfall, temperature, latitude)

Fight Against Malaria In 1998, the WHO, World Bank, UNDP and UNICEF conceived and partnered to create the Roll Back Malaria movement Red – insecticide treated bed nest Blue – insecticide residual spraying Green – both White - undetermined

Conclusion High exposure to DDT will affects the nervous system, shorter lactation period in women. Further test will still need to be conducted, to determine the benefits versus the health risks of using DDT Well coordinated efforts in combination with efficient health infrastructure should have better success in malaria control

References 1. Beard J. DDT and Human Health. Science of the Total Environment 2005; 355: Rogan WJ, Chen A. Health Risks and Benefits of DDT. Lancet 2005; 366: tml tml