We are proponents of organic farming and a pesticide-free environment. Pesticides, at first glance, seem to be beneficial to humans and the crops they grow. After all, bugs and varmints destroy those crops, don’t they? And certain breeds of insect, mosquitoes for instance, actually carry disease such as Malaria and yellow fever. You would think that targeting just those particular breeds of pest that are directly harmful to humans would be okay wouldn’t you? It’s been tried before, with disastrous results to not only humans, but our entire eco-system. We are still feeling the effects, almost forty years later.
DDT and the American Bald Eagle
Does it seem odd to you that the national bird of the United States was, until 2007, an endangered species? When we first chose the American Bald Eagle to be our national symbol there were an estimated 500,000 of them throughout North America. During the 1950s, there were only 412 nesting pairs in the forty-eight continental United States. How did that happen? We did it. The pesticide DDT, created in 1939 and used widely throughout the 1940s and 50s, nearly killed off the proud symbol of American freedom and liberty. The widespread spraying of DDT caused a calcium deficiency in the birds that resulted in thinner egg walls that could not be incubated by the mothers. The adult bald eagles literally crushed their own offspring before they could be born.
Another bird affected by DDT was the Peregrine Falcon, one of the most common predatory birds in the world. This breed of falcon lives on a diet of smaller birds and small mammals, so it did not consume the sprayed crops directly, but through a higher member of the food chain. Like the bald eagle, the ingestion of DDT caused thinner egg shells and often sterility, leading to a significant decline in the number of Peregrines found in North America. Those numbers are rising today, but this amazing creature is still fairly scarce in the mountain ranges of the US.
“Silent Spring” and the US Ban on DDT
In 1962, Rachel Carson, at the urging of “New Yorker” Editor William Shawn, wrote a book called “Silent Spring”, which documented the effects of pesticides on our environment. She made particular note of DDT, outlining how it was affecting the predatory bird populations of the United States and the various ailments it was contributing to in human beings – including Cancer. Though Carson didn’t call for an outright ban on the pesticide, the public did. President Kennedy ordered his Science Advisory Committee to investigate her claims and eventually the chemical was banned from production and use inside the United States. The ban went into effect in 1972 and still stands, despite several challenges.
Use and Effects of DDT Today
There are many in the US and throughout the world who are opposed to the ban on DDT, claiming that the lives saved from malaria more than justify its use. In certain countries, it is still used to spray interior walls of homes to repel mosquitoes, a loophole in the ban that is called vector control. The impact of that is significantly less on the environment than the use of DDT to spray cotton or other crops, but it still negatively affects the people inside those houses and the soil and water beneath them. DDT has been linked to Diabetes, Cancer, sterility, and birth defects. It takes up to fifteen years to dissolve in soil and is toxic to fish, one of the main elements of our food supply. In some areas, including the Great Lakes region of the US, there are still warnings in effect for fish contaminated by DDT that comes from atmospheric deposition. Until the chemical is banned worldwide for any use, this will continue to be the case.