Pesticides that Disrupt the Endocrine System

hormone systemendocrine glands





A 2013 report by the Beyond Pesticides organization summarizes the human health hazard from pesticides, and tells how the EPA is over a decade behind in thorough evaluating almost a hundred pesticides suspected as endocrine disrupting chemicals (EDC). The list of known or suspected hormone disruptors includes 15 herbicides, 13 fungicides, and 26 insecticides. Researchers have identified about 200 synthetic chemicals – most of them everywhere in the environment – that disrupt the production or action of hormones. The tally of known or suspected hormone disrupters includes: PCPs, BPA, chlorinated pesticides (like DDT), PBDEs, phthalates, PFOA, PAHs, keptone (an insecticide), vinclozolin (a fungicide), and nonylphenol (a breakdown product of some detergents). Some of these chemicals can linger in the body for years, even if no more enters the body.

If you had not read earlier posts on this topic, you might ask “Why the concern”? According to Dr. Colborn, EDCs have been implicated in studies of marine animals that show increased sterility, growth retardation, diminished immunological function, and reproductive abnormalities. Atrazine, one of the most abundantly applied herbicides in the U.S. chemically castrates and feminizes male amphibian larvae and their growth and development.

Research has shown that chemicals that disrupt the endocrine system often have entirely different effects on the human embryo and developing fetus than they do on an adult, and thus, the effects are often seen in the offspring rather than in the parents. Very low-dose exposures during fetal development can be damaging to embryos, whereas high-dose exposures may have no effect on adults. Because hormones orchestrate many critical aspects of development, from sexual differentiation to brain organization, hormone-disrupting chemicals pose a particular hazard before birth and early in life.

Reproductive specialists attribute a worldwide sperm count decline of 50% since 1930 to exposures to EDCs. Higher levels of organochlorine chemicals are found in fat samples of males with undescended testes. Scientists believe that many neurological disorders in children, such as ADHD and autism may be related to prenatal disruption of the thyroid system. It is known that chemicasl that interfere with thyroid function also interfere with brain development in the developing fetus. Phthalates, widely found in pesticide formulations as inert ingredients are found in 75% of urine samples from normal men. Such phthalates have been found to interfere with the thyroid system, as well as reducing testosterone levels.

This subject is important enough that the World Health Organization issued a special report on the subject: State of the Science of Endocrine Disrupting Chemicals 2012. (See


About donlouis

The author has long had a keen interest in staying healthy and fit, and in doing whatever I can to keep the natural environment unpolluted and a healthy space for people and all animals. As a former Board Member of a municipal water district, I regularly had to deal with the issue of water quality. I first became aware of radiation hazards from toxic materials while working on uranium for nuclear reactors. During the 1960s I was tuned into the global hazard from Strontium 90 raining down from atmospheric testing of nuclear bombs. While working in the chemical industry in later years I became aware of the many forms of chemical contaminants entering the environment every day, and resolved to do something about it. I am able to make sense out of the voluminous descriptions of common toxic chemical because of my training in chemistry, with a Ph.D. degree and several decades of research and development work in the chemical industry. My training and experience enables me to present to readers reliable and current information on the topic of chemical hazards in the environment, and their threats to human health. All my life I have loved hiking and camping in nature. Skiing, river kayaking, and tennis have been my favorite physical activities. Nature photography is my artistic passion.
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