Dear EarthTalk: I understand there is good news about the recovery of bird species like the Peregrine falcon, bald eagle and others owed to the 1972 ban on DDT. Can you explain? -- Mildred Eastover, Bath, Maine

Rachel Carson's seminal 1962 book, "Silent Spring," told the real-life story of how bird populations across the country were suffering as a result of the widespread application of the synthetic pesticide DDT (dichlorodiphenyltrichloroethane), which was being used widely to control mosquitoes and others insects. Carson reported that birds ingesting DDT tended to lay thin-shelled eggs which would in turn break prematurely in the nest, resulting in marked population declines. The problem drove bald eagles, our national symbol, not to mention peregrine falcons and other bird populations, to the brink of extinction, with populations plummeting more than 80 percent.

Luckily for the birds, "Silent Spring" caused a stir, and many credit it with launching the modern environmental movement. Indeed, one of the world's leading environmental nonprofits, the Environmental Defense Fund (EDF), initially formed in 1967 in reaction to the DDT problem. The group's first order of business included filing lawsuits in New York, Michigan, Wisconsin and Washington, D.C., to force a ban on DDT. EDF enlisted the help of dozens of scientific experts -- ornithologists, ecologists, toxicologists, carcinogenesis experts and insect control specialists -- to testify at multi-month hearings to prove its point in regard to the dangers of DDT. In 1972 environmentalists' prayers were answered -- and their hard work vindicated -- with the federal government finally banning DDT.

But with lots of the pesticide already dispersed through ecosystems far and wide, not to mention myriad other threats to bird habitats and the environment in general, no one could be sure whether populations of eagles, falcons and other predatory and fish-eating birds would come back from the brink. While the federal Endangered Species Act went a long way to protect these at-risk species and some of their habitat, nonprofits also played a key role in helping specific species recover. To wit, the Peregrine Fund was founded in 1970 by a leading Cornell ornithologist to help nurse peregrine falcon populations hit hard by DDT back to their once abundant numbers. Researchers with the group pioneered methods of breeding peregrines in captivity and releasing them into the wild; such techniques have since been adopted widely by biologists trying to bring other wildlife species back from the brink of extinction. Thanks to a combination of factors and the hard work of bird lovers and scientists, peregrine falcons are once again common across the U.S., graduating off the national endangered species list as of 1999.

The bald eagle's recovery is perhaps the best known example of how our environmental laws worked to restore not just a resource but our very national symbol. In the mid-1960s fewer than 500 nesting pairs of bald eagles existed in the continental U.S.; today, thanks to the DDT ban and other conservation efforts, some 10,000 pairs of bald eagles inhabit the Lower 48 -- that's a 20-fold population increase in just four decades. In 2007 the federal government removed the bald eagle from the Endangered Species List. Without the 1972 ban on DDT and ensuing protections, the bald eagle, let alone dozens of other bird species, would likely be gone now in the continental U.S. And without the song of the birds, the spring would be a very silent time indeed.

Contacts: EDF,; Peregrine Fund,

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Dear EarthTalk: A few years back a study found more than 200 chemicals in the umbilical cords of newborns, particularly African American, Asian and Hispanic babies. What are the causes of this phenomenon and what can be done about it? -- Bettina Olsen, New York, N.Y.

The study referenced found traces of some 232 synthetic chemicals in cord blood samples from 10 different babies of African American, Asian and Hispanic descent born in 2009 in different parts of the U.S. Study sponsors Environmental Working Group (EWG) and Rachel's Network were looking to find out if the hormone-disrupting chemical Bisphenol A (BPA), a plasticizer widely used in food and drink storage containers, is present in the cord blood of minority babies in the U.S. Sadly and not surprisingly, BPA turned up in nine of the 10 cord blood samples tested. But perhaps even worse is the study's detection of whole new raft of chemicals showing up in babies' cord blood for the first time. Some of these newer offenders include tetrabromobisphenol A (TBBPA) from computer circuit boards, synthetic fragrances used in common cosmetics and detergents and Teflon-relative perfluorobutanoic acid.

The 2009 study was a follow-up to an earlier analysis of chemicals in cord blood in the mainstream U.S. population during 2004 births. That earlier study found some 287 different industrial chemicals and pollutants in babies' cord blood, although BPA was not yet on EWG's watch list at the time. The more recent study focused on minority babies because minority communities in the U.S. tend to bear a disproportionate pollution burden given their closer proximity to busy roads, industrial sites and older housing. But EWG points out that they tested for chemicals that are likely found in virtually every American household, so none of us are immune to exposure. EWG hopes that by continuing to monitor the chemicals we are born with it can hold corporate polluters' and government regulators' feet to the fire in regard to waste outputs and pollution mitigation.

EWG did not look for chemicals associated with smoking or alcohol consumption on the part of mothers, instead focusing on contaminants from exposures to consumer products and commercial chemicals omnipresent on supermarket shelves. To EWG, the presence of these chemicals in umbilical cord blood represents "a significant failure on the part of the Congress and government agencies" charged with protecting human health. "Our results strongly suggest that the health of all children is threatened by trace amounts of hundreds of synthetic chemicals coursing through their bodies from the earliest stages of life."

Part of the problem is outdated laws governing the handling and use of toxic chemicals. Currently 1976's Toxic Substances Control Act is the law of the land in regard to controlling the distribution, use and disposal of toxic chemicals nationwide. But EWG and other groups complain that hundreds of thousands of new chemical formulations are unleashed on an unwitting public every year via America's store shelves because the federal government assumes new products and ingredients to be innocent until proven guilty. These critics would like to see the federal government take a more proactive role in approving new substances for use in consumer products, not to mention residential and workplace environments.

On the legislative front, green groups are pinning their hopes for a reformed Toxic Substances Control Act on New Jersey Democratic Senator Frank Lautenberg's Safe Chemicals Act (S. 847), introduced last fall. The bill is currently spinning its wheels in committee hearings, but its 17 bi-partisan co-sponsors are optimistic that it will come up for a floor vote before the 112th Congress wraps up the end of this year.

Contact: EWG's "Pollution in Minority Newborns,"

EarthTalk is by Roddy Scheer and Doug Moss of E -- The Environmental Magazine ( Send questions to: