In 1962, marine biologist and zoologist Rachel Carson changed broke new ground when she published Silent Spring, which documented how birds' eggs were thinning due to exposure to the pesticide DDT, resulting in an alarming decrease in the bird's ability to reproduce. There is still plenty we can learn about environmental contaminants by monitoring animal populations in the wild. While what affects animals will not necessarily affect humans, the effects of contaminants on animal health certainly raises important concerns.
Frogs Researchers have found evidence that atrazine-the most commonly used herbicide in the United States and probably in the world-can cause hermaphrodism (having both male and female reproductive organs) in frogs in the laboratory and may be responsible for the same impacts seen in frogs in the wild. Atrazine is widely used on corn and soybean fields in the United States and contaminates drinking water supplies.
Alligators Studies of alligators in a Florida lake contaminated with DDT and other organochlorine pesticides in the 1980s found the males' penises were on average 25 percent smaller than normal. These alligators, at the top of the lake's food chain, ate fish that store the breakdown products of DDT. These byproducts accumulated in the alligators' bodies and caused changes in the hormonal system.
Birds Hundreds of bird deaths have been reported from toxic fumes produced from normal household use of Teflon pans and products. According to the Environmental Protection Agency, perfluorooctanoic acid (PFOA), one of the key compounds used in Teflon, is very persistent in the environment and can be found in the blood of the general U.S. population. Studies indicated that PFOA causes developmental and other adverse effects in laboratory animals.
Polar Bears Studies indicate that polar bears are threatened by chemicals accumulating in the environment. Initial studies indicate that polychlorinated biphenyls (PCBs) and other chlorine-based chemicals may be causing polar bears' ovaries and testicles to shrink, which may interfere with their ability to reproduce.
Researchers have found evidence that atrazine-the most commonly used herbicide in the United States and probably in the world-can cause hermaphrodism (having both male and female reproductive organs) in frogs in the laboratory and may be responsible for the same impacts seen in frogs in the wild. Atrazine is widely used on corn and soybean fields in the United States and contaminates drinking water supplies.
Studies of alligators in a Florida lake contaminated with DDT and other organochlorine pesticides in the 1980s found the males' penises were on average 25 percent smaller than normal. These alligators, at the top of the lake's food chain, ate fish that store the breakdown products of DDT. These byproducts accumulated in the alligators' bodies and caused changes in the hormonal system.
Hundreds of bird deaths have been reported from toxic fumes produced from normal household use of Teflon pans and products. According to the Environmental Protection Agency, perfluorooctanoic acid (PFOA), one of the key compounds used in Teflon, is very persistent in the environment and can be found in the blood of the general U.S. population. Studies indicated that PFOA causes developmental and other adverse effects in laboratory animals.
Studies indicate that polar bears are threatened by chemicals accumulating in the environment. Initial studies indicate that polychlorinated biphenyls (PCBs) and other chlorine-based chemicals may be causing polar bears' ovaries and testicles to shrink, which may interfere with their ability to reproduce.