Endocrine disrupting chemicals are toxic chemicals that occur in the environment and have hormone-like effects on animals, including humans. These effects are potentially harmful to normal sexual development, male and female reproductive health, and fertility issues like sperm quality. They are called endocrine disruptors because these chemicals can mimic, block, or otherwise affect the body's naturally occurring hormones. Such chemicals have a number of man-made sources, from pesticides and herbicides to additives used in various plastics. Due to their persistence in the environment and their ability to accumulate in animals, endocrine disrupting chemicals are both an environmental and health concern.
The endocrine system uses hormones to regulate a number of bodily processes, including growth and the proper development of sexual characteristics. Also known as hormonally active agents, endocrine disruptors are problematic because they are similar enough to natural hormones to be mistaken by the body. Once they are recognized, endocrine disrupting chemicals can cause abnormal developments that would not have otherwise occurred. The endocrine system regulates many of the body's functions, and endocrine disruptors have been linked to abnormal sexual characteristics, breast and prostate cancers, and lowered immune health.
In the wild, endocrine disrupting chemicals have been found to have harmful effects on the sexual development of male amphibians like frogs, as well as reptiles and birds. Male frogs in some parts of the United States have been found to have sexual abnormalities in their gonads, and in some cases to have both male and female reproductive parts. Some alligators have been found to have reproductive problems that include fewer eggs, reduced penis size, and other issues associated with reproductive organs. Such chemicals may also lower the reproductive rates of various bird species and possibly mammals.
Different types of chemicals can have endocrine disrupting effects. Along with agricultural chemicals, other hormonally active agents include phthalates, which are a class of plastic additives, and polychlorinated biphenyls (PCBs), which have industrial uses in coolants or insulation. Bisphenol-A (BPA), a plastic additive that has effects similar to human hormones, is widely used in thermal paper and plastic food containers.
Male reproductive health seems most sensitive to the effects of endocrine disrupting chemicals. A number of studies in the second half of the 20th century found male human sperm to be declining in quality and number, which may or may not be related to environmental exposure to these chemicals. Those wishing to lower their exposure may decide to avoid using plastic in the kitchen, wash fresh produce, and not take the receipt after purchases.