Gotowa bibliografia na temat „DDT (Insecticide) Environmental aspects”

The late 1960s and early 1970s was a world of increasing political unrest on many fronts. In January 1969, Richard Nixon replaced Lyndon Johnson as president. Public support for the war in Vietnam was diminishing and there were widespread antiwar demonstrations. Environmental awareness and concerns were rapidly increasing. Air and water pollution were increasingly severe. A huge oil spill dumped 100,000 barrels of crude oil onto the beaches of Santa Barbara, California. The Cuyahoga River in Ohio caught fire. Students buried automobiles on college campuses. Lake Erie could no longer support fish. The great whales were being killed in record numbers. People were apprehensive about pesticides. The Bald Eagle, national symbol, was disappearing. The first Earth Day was launched in 1970. Responding to this public outcry, the National Environmental Policy Act passed Congress almost unanimously and became law on January 1, 1970; the Clean Air Act became law in 1970, the Clean Water Act in 1972, and the Endangered Species Act in 1973; and the Federal Insecticide, Fungicide and Rodenticide Act was rewritten in 1972. Rachel Carson’s Silent Spring had appeared in 1962 and generated a sizable public reaction, but pesticide policies had changed very little by 1970. This was the milieu in which EDF sought to pursue its goals of a national ban on DDT and the development of environmental law. Reaching those goals would require a much more substantial organization than EDF was in 1969; at that time it was little more than a board of trustees with plenty of ideas but no staff, no office, and almost no money. Most of those trustees were going about their normal lives with EDF concerns more like a hobby than a profession. Their dedication was strong and very real, but a strategic game plan was barely in sight. There were additional impediments when compared with today’s world. Forty-five years ago communications barely resembled what we have now. Most television sets were black-and-white with small screens and large bulky bodies, although color TV was arriving slowly. There were no computers or cell phones.

By the fall of 1969 we knew we had to challenge pesticide regulation by the federal government if we were to ultimately prevail against DDT, but we did not know how to do it. We had the science well in hand and knew how to present it, with literally hundreds of scientists prepared to testify within their areas of expertise. We did not have the organizational structure to launch such an effort at the federal level, however, and we were certainly short of money. At about that time Joseph L. Sax, then the leading proponent of the development of environmental law at the University of Michigan Law School, suggested that we contact the newly founded Center for Law and Social Policy (CLASP), a public-interest law firm in Washington, DC. Joe was a member of the CLASP board. He insisted that DDT was in violation of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and that the U.S. Department of Agriculture (USDA) was not enforcing FIFRA. I therefore called and talked at length with James W. Moorman (Fig. 7.1), attorney for CLASP, describing the DDT problem and proposed action against USDA. “If we are going to do this, then you are going to come down here and help me put the case together,” said Jim firmly. That was not music to my ears: I had other things I needed to do, but shortly I was on my way to Washington. CLASP was in a rundown part of Washington, and my “housing” consisted of sleeping on an old mattress in their dusty attic. But we got to work and wrote a petition to USDA in about a week. The petition was a formal legal request that the FIFRA registrations for DDT be canceled. The petition also requested that USDA suspend the registrations while it was considering their cancellation. We had no illusions that USDA would grant our request, but it was Jim’s advice that we go to USDA for administrative relief before seeking cancellation and suspension from the courts.

The more species are removed from each other in evolutionary development, the greater is the likelihood of differences in response to toxic agents. One obvious difference that affects toxicity is the size of the organisms. Much less toxin is needed to kill a small insect than a considerably larger mammal (everything else being equal). In addition, there is an inverse relationship between the weight of an animal and its surface area; the smaller the animal, the larger its surface area per gram of weight. Thus, the weight ratio of a human being (70 kg) to a rat (200 g) is 350, but the surface area ratio of a human being to a rat is only 55. Roughly, the surface area of an animal (S) can be calculated as follows: S(m2) = weight (kg)2/3/10. This type of calculation is important when one is considering the selective eradication of an uneconomical species, such as certain insects, by spraying an area with insecticide. The goal is to control the insects without harming wildlife, livestock, and human beings. Other factors, such as the rate of percutaneous absorption, also have to be considered. For instance, it has been shown that DDT (dichlorodiphenyltrichloroethane) is about equally toxic to insects and mammals when given by injection, yet when applied externally it is considerably more toxic to insects. This toxicity is due not only to the difference of the surface area:- body weight ratio, but also to the fact that the chitinous exoskeleton of the insect is more permeable to DDT than unprotected mammalian skin (1). Of course, in real-life situations (i.e., outside the laboratory), most mammalian skin is covered by fur, which gives the animals additional protection. The foregoing discussion is not meant to imply that unrestricted spraying with pesticides (especially chlorinated hydrocarbons, which are fat-soluble and poorly biodegradable) is environmentally sound. Problems with their use include lack of selectivity among insect species; leaching into watersheds and groundwater; and bioaccumulation in the food chain. These problems will be discussed in detail in Chapter 11. Metabolic-pathway differences among species may provide another rationale for achieving selective toxicity