Syndicated columnist Walter Williams (“We are the idiots: Dire environmental predictions falling flat,” May 23) 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.
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 mosquitoes that 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 bed nets and nonchemical 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 a simple 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.
Mr. Williams’ uninformed attack supports a regression to the days when 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.