For decades scientists have monitored the Palos Verdes Shelf,considered by many to be the most studied piece of ocean floor on Earth where there were thought to be approximately 110 tons of DDT. According to the latest analysis, EPA scientists estimate that there is now only about 14 tons of the insecticide remaining. Despite independent experts verifying the EPA's findings, some scientists simply will not accept the data and are calling for more remedial action that is not a risk-free exercise.
In 2000, the EPA declared that the site posed "an unacceptable risk to human health and the environment," and were planning to cover part of the Shelf with a thick cap of clean sand, unprecedented in deep ocean waters, at an estimated cost of $60-million. Given the latest data, there now seems to be little justification for the controversial cap. The DDT deposit has not only shrunk in size, but the peak concentrations have dramatically reduced. In fact, the current levels match what the EPA had hoped to achieve with the cap.
According to a report in Environmental Health News, EPA site manager Judy Huang says, "We've either achieved [our goal] without the cap, or close to it". And, "We have a lot better understanding now based on the [latest available] data". Moreover according to Joseph Gully who is the supervising environmental scientist at the Los Angeles County Sanitation District, "We've been seeing declines in [DDT concentrations in] fish tissues and surface sediments for the past 20 years", yet some environmental scientists are now calling for extensive studies to measure DDT levels in fish and other marine life.
DDT has been a cash cow for thousands of scientists and innumerable environmental groups for decades. We can detect DDT in the environment now thanks to incredibly sensitive assays. The reality is that the small quantity of DDT present in the environment is vanishing and poses no threat to wildlife, if indeed it ever did. Most of the research relied upon by early anti-DDT campaigners such as Rachel Carson, has been shown to be wildly exaggerated.
Countless thousands of studies have been conducted into the potential for DDT to cause harm to human health, yet they have come up short. DDT was used extensively in the United States from the late 1940s to early 1970s and was ubiquitous in the food chain. Yet during those years of heavy DDT use, there was no worsening of health outcomes for Americans, indeed life expectancy and health continued to improve. After DDT use was abruptly halted in 1972, no sudden improvement in any health indicator became apparent, rather the same steady improvement in health and welfare continued.
The banning of DDT in the United States and other developed countries led to a shortage of the chemical and the restrictions imposed on its use against malaria cost many lives in developing countries.
There was another great and largely unrecognised cost incurred by the vilification of DDT. Thanks to anti-DDT campaigns, the regulatory barriers to developing new insecticides have been artificially inflated to such an extent that now it costs hundreds of millions of dollars to bring a new product to market. The campaigns also dried up public research funds for insecticides to eradicate insect-borne diseases. Research for new products to control disease-spreading insects comprises just a tiny fraction of the amount spent on new vaccines and drugs. Any malaria control programme is built on a foundation of insecticide use, but there has not been a new insecticide for disease control for more than 30 years.Scientists should be rejoicing the diminishing levels of DDT. They should be screaming for policies and funds, not to conduct another unnecessary DDT study, but to research and develop a new public health insecticide and save thousands of lives.
Author: Jasson Urbach is a director of the Health Policy Unit and of Africa Fighting Malaria. The views expressed in the article are the author's and are not necessarily shared by the members of his respective organisations.