Who is history’s greatest villain? If we measure villainy in number of victims, Stalin, Hitler, and Mao are often cited. Stalin and Hitler are often cited as being responsible for 25 million deaths each. However, one of the primary causes of World War II was the Molotov–Ribbentrop Pact, signed by both dictators, which would indicate a shared responsibility for World War II. A Hong Kong-based historian blames Mao for about 45 million deaths in the four years, 1958 to 1962, as well as several million more during the “great cultural revolution” a few years later. [1, 2] Your author, as a history buff, believes those numbers are plausible. But all three of those historical figures were dictators in complete control of their respective countries. Of course the dictators themselves did not pull any triggers. Rather they used their authority to set in motion the minions that actually did the dirty work. Here I posit a villain who is responsible for the deaths of about 80 million people, mostly children.
Rachel Carson is honored as one of the founders of the American environmental movement.
A variety of groups ranging from government institutions to environmental and conservation organizations to scholarly societies have celebrated Carson's life and work since her death. Perhaps most significantly, on June 9, 1980, Carson was awarded the Presidential Medal of Freedom, the highest civilian honor in the United States[97] A 17¢ Great Americans series postage stamp was issued in her honor the following year; several other countries have since issued Carson postage as well.[98] Carson's birthplace and childhood home in Springdale, Pennsylvania—now known as the Rachel Carson Homestead—became a National Register of Historic Places site….Her home in Colesville, Maryland where she wrote Silent Spring was named a National Historic Landmark in 1991. [3, refrence numbers from that article]
Carson’s chief claim was that pesticides were destroying wildlife and causing vast harm to humans. Her damnation of DDT was especially convincing and resulted in a ban of DDT in the US and other countries. Her great work, Silent Spring, is acknowledged as one of the great drivers of the ban. No one disagreed that DDT was great at killing and repelling insects. It was also cheap. One of DDT’s great benefits was its persistence – it would keep on killing insects for years. Public health authorities in Third World countries defended DDT when its ban was first proposed, and some still defend DDT today. Why? Malaria, a mosquito borne disease, is endemic in tropical and semi-tropical countries. DDT controlled malaria at a reasonable cost. Its persistence could compensate for inefficiencies in its application.
How good was DDT at controlling malaria?. “The widespread spraying of DDT had caused a spectacular drop in malaria incidence–Sri Lanka, for example, reported 2.8 million malaria victims in 1948, but by 1963 it had only 17.” [4] Another example, “At the time of the DDT ban in 1972, 1 billion people were almost malaria-free.” [5]. According to these CDC figures, malaria kills more than 800,000 children under age five every year. Every year, 800,000 small children die from malaria, a disease once nearly eradicated. [6. from a reputable source, but I can’t pull up the CDC original]
Your author has read many of Carson’s books and can attest she is a great author – easy to read science with gripping examples. However she took great liberties with science and her writing should not be quoted as science. [11, 12, 13] However, the objections to DDT follow two main lines, its persistence and its toxicity to humans.
Regarding its persistence, there is little doubt. How persistent is DDT? Or since DDT is metabolized to DDE, how persistent are both? They are both are stored in the body fat. DDT was banned in the US from 1972. . In surveys of human breast milk, prior to 1986, DDT was found in virtually all samples and had a range of 0.2 to 4.3 ppm, likewise DDE ranged from 1.2 to 14.7 ppm. However my source publications do not have details about the dates – how long before 1986? I’m not sure. Anyhow, in surveys done in 1986 in Arkansas, DDT was found in only 19% of the samples and the range of those was from 0.039 to 0.203 ppm. [7] Whether the DDT was taken up and stored those 14 years, or did exposure from contaminated plant and animals continue – my guess is both. In studies in the UK done in 2001 to 2003, researchers found a DDT range of 1.1 to 760 ppb in milk lipids and DDE concentrations of 22 to 1600 ppb. (Some of the mothers in UK may have emigrated from other countries. ) [7] Regardless of the details, it is certain that DDT and DDE are persistent in the environment and humans continued to be exposed long after the ban. Gross.
Is DDT is harmful at those concentrations, and are adverse human health effects are attributable to those residual concentrations or the original exposure? ASTDR has references to hundreds of studies; some show some correlations while others show no correlation with disease or adverse pregnancy outcomes. [8] Most of these studies related to DDT/DDE’s purported role as an endocrine disruptor. Regardless of the studies, would I want my children to breast feed on milk that has even 1 ppm of DDT? Of course not, gross, science forbid. But then, my kids were raised in Alaska, not a malaria hot spot. How about if I were working in the Niger Delta? Would I trade 5 ppm of a harmless (probably) contaminant in breast milk for a vastly reduced chance of me or my family contacting malaria? Many varieties of malaria are essentially life-long diseases. How about the citizens of Florida and the Islands confronted with the Zika outbreak? [9] The choice between exposure to DDT and children with microcephaly would not be hard for most people.
Regarding effects other than endocrine disruption, especially cancer, most studies have shown no acute or chronic effects. A few have. WHO catalogs four levels of pesticide toxicity: slightly, moderate, highly and extremely – DDT is listed as moderately toxic.[10] At the time Carson wrote, it was already known that humans experienced no ill effects after consuming 35 milligrams of DDT daily for two years — a dose 1,000 times higher than that received from agricultural exposure [5]. Of course at very high doses many chemicals can evoke cancer in lab animals (Bruce Ames was one of the 11 co-signatories below).
Before we blame poor Rachel for all these deaths, though, a closer reading of her works indicates she understood the dangers of insect borne disease and did not favor banning of pesticides, just a more reasoned approach to their application. Something I would have agreed with, since DDT was so cheap, it was often grossly over-applied. Its persistence is also a benefit, since it does not need to be applied as often. However religion often trumps science. Carson is regarded as a saint in the environmental community, her home is a mecca for green tourists and she has been honored posthumously by just about all environmental groups.
References, most of which are in the Course Documents folder.