Walter Williams falsely claims that environmentalists’ urging of restrictions on the pesticide dichlorodiphenyltrichloroethane (DDT) is responsible for the death of tens of millions from malaria. He then uses this claim and others to attack environmental regulation and environmentalists’ warnings of future harms from unregulated production and consumption.
The 2001 Stockholm Convention on Persistent Organic Pollutants regulating DDT specifically allows its use in indoor residual spraying (IRS) for control of vectors of malaria and visceral leishmaniasis. Spraying the pesticide on the inside walls of dwellings repels the mosquito which transmits the malaria parasite. Unfortunately, this also poisons the residents and the workers applying the pesticide. While the health effects of malaria are more severe than those of DDT, the existence of other alternatives to reduce malaria’s morbidity and mortality, such as bednets and non-chemical environmental management, led a panel of scientists from the United States and South Africa in 2009 to recommend that DDT “should only be used as a last resort in combating malaria.”
Most importantly, mosquitoes acquire resistance to DDT even when used properly in IRS. There is evidence that mosquitoes also acquire resistance to DDT from synthetic pyrethroids, a group of chemicals similar to DDT used in agricultural pesticides. So to treat DDT as the solution to malaria is simply wrong.
Rachel Carson‘s struggle to bring to the public’s attention the dangers of unrestricted pesticide use made her an American hero and a worldwide icon, and Mr. Williams’s uninformed attacks on her are an attempt to return us to the days where people and corporations produced and consumed without knowledge of and consideration for the harms they inflicted on themselves, others and the other creatures with whom we share this planet.
Updated May 31, 2013: The local paper published a version of this blog entry as a letter to the editor.
Additional thoughts and quotes:
Rachel Carson never advocated a global ban on pesticides.
Many African governments where malaria is endemic continue to collect import tariffs on insecticide-treated bednets and antimalarial drugs despite the May 2000 Abuja Declaration’s pledge to do away with “malaria taxes.”
Restricting the use of DDT has helped restore North American bird populations.
Debating the Health Effects of DDT: Thomas Jukes, Charles Wurster, and the Fate of an Environmental Pollutant outlines the history of arguments related to DDT in the United States.
Turusov V, Rakitsky V, Tomatis L. Dichlorodiphenyltrichloroethane (DDT): ubiquity, persistence, and risks. Environ Health Perspect. 2002;110:125-8.
The presence and persistence of DDT and its metabolites worldwide are still problems of great relevance to public health. Efficient pesticides that do not have the negative properties of DDT, together with the development of alternative methods to fight malaria, should be sought with the goal of completely banning DDT.
A LITERATURE REVIEW OF THE USE OF DDT TO FIGHT MALARIA
Linah Adhiambo Nyamori, The University of Texas School of Public Health
Indoor spraying of DDT in malaria endemic areas may cause increased exposure of the chemical to humans; however I conclude that the overall benefits outweigh the risks because more lives are saved due to fewer infections with malaria.
I could not access the full text of this dissertation.
Anders Ruusa, Norman W. Green, Amund Maage, Carl Einar Amundsen, Merete Schøyen, Jens Skeia. Post World War II orcharding creates present day DDT-problems in The Sørfjord (Western Norway) – A case study. Marine Pollution Bulletin. 2010;60: 1856-61.
DDT was used as an insecticide in orchards surrounding the fjord between World War II and 1970. Since the early 1990s, elevated concentrations of DDT were found in mussels and fish. Unexpectedly, DDT-concentrations increased towards present day, despite the discontinuation of use.
Advancing an argument that DDT should be continued because DDT’s negative effects are so much less than are the effects of malaria on mortality or morbidity, and then ending the discussion there, ignores the rights of people to a safe environment, or at least to live safely in a compromised environment. The situation can be compared with taking prescription medicine. Prescribing a drug for a malady is expected to improve or eliminate the malady, but there are possible side effects. Patients are informed of these side effects, and actions can be taken if required. These are ethical obligations of medical treatment currently not very prominent in the communication of the public health use of toxic chemicals. Much more attention should therefore be focused on informing the public about the advantages of malaria control, even if this still requires DDT, and ways and means to reduce exposures. Also, if communities suffer effects at rates above the norm, and the existing health support infrastructure is not equipped to recognize or deal with it, additional and targeted support systems must be contemplated once the extent of the need has been established through research. [source]
We now have half a century of evidence that routine use of DDT simply will not prevail against the mosquitoes. Most countries have already absorbed this lesson, and banned the chemical or relegated it to emergency only status. Now the RBM campaign and associated efforts are showing that the frequency and intensity of those emergencies can be reduced through systematic attention to the chronic aspects of the disease. There is less and less justification for DDT, and the futility of using it as a matter of routine is becoming increasingly apparent: in order to control a disease, why should we poison our soils, our waters, and ourselves? [source]