Gutting the U.S. Environmental Protection Agency, as President Trump proposes in his recently released budget, would progressively erode the health of this and future generations.
Chemical pollutants that disrupt the endocrine system are prime examples of the danger of slashing funds to this vital agency.
Dr. Clif Cleaveland
Think of the endocrine system as a delicately coordinated array of glands, such as the pituitary, thyroid, adrenal, ovaries and testicles, that regulate our metabolism, growth and reproduction.
More than 1,000 chemicals are known to interfere with endocrine function. They may be dispersed in air, water and soil. We encounter them in our diet, cleaning agents, pesticides and personal care products such as cosmetics. Endocrine-disrupting chemicals, or EDCs, may pollute our home, recreational and work environments. Because of careless or illegal disposal, many of the chemicals are widely dispersed in nature where they may persist for decades, since there are no naturally occurring means for the degradation of most of these substances.
Some of the chemicals are directly toxic to a gland. Other chemicals mimic the action of some hormones. Still others block the action of hormones by attaching to specific receptors through which a hormone exerts its actions within the body. The endocrine glands of fetuses and infants are especially susceptible to these effects.
Most of what we know about EDCs derives from studies employing experimental animals or cultures of human cells. Direct effects upon humans are seen in occupational or accidental exposures. Higher blood levels of EDCs are associated with increased risks of specific diseases.
A sampler of potent EDCs includes the following:
- DDT, a widely used insecticide until its ban in the U.S. in 1972, interferes with normal menstruation and ovulation and diminishes sperm quality. DDT also interferes with thyroid gland function.
- Dioxin and dioxin-like chemicals are potent EDCs and carcinogens. These compounds may occur as contaminants or byproducts of industrial processes. Included in this classification are polychlorinated biphenyls (PCBs), widely used in transformers and electrical equipment. Although the manufacture of PCBs was stopped in 1977, they persist and accumulate in nature, especially in areas where large amounts were dumped in rivers. PCPs are ingested in the diet and accumulate in body fat. They interfere with reproductive hormones and brain and immune system development.
- Flame-retardant chemicals, which are in building insulation, electronics and furniture manufacture, disrupt thyroid function. These chemicals are widely dispersed and persist in nature and in the human food chain. These substances interfere with thyroid function and have been linked to behavioral abnormalities in infants and children.
- Bis-phenol A and other chemicals used in the manufacture of plastics are widely disseminated in the environment. These chemicals are used in the manufacture of plastic bottles, storage containers and coatings of food cans. BPA levels are detectable in the great majority of Americans age 6 and older. BPA is a weak estrogen. It is no longer used in baby bottles or packaging for infant formula. Its toxicity for adults is unsettled. Increasing numbers of food products advertise that they are "BPA-free."
- Organophosphates are common components of many insecticides. They affect fetal brain development and decrease fertility by reducing testosterone levels.
- Atrazine, a widely used herbicide, has been linked to feminization of males, delayed puberty and breast cancer.
Other EDCs include lead, arsenic, chemicals used in nonstick cookware and perchlorate, a component of rocket fuel.
The nonprofit, nonpartisan Environmental Working Group (www.ewg.org) is an excellent source of information on EDCs and other toxins.
Each of these chemicals generates heated debate regarding toxicity and safety among manufacturers, politicians, environmental advocates and government regulators. The key question: What are safe levels in the environment and in the human body?
The EPA is at the center of research and monitoring of EDCs and numerous other chemicals that impact human health. Many manufacturers see the EPA as a threat to profits and fight the agency at every turn. Sometimes, as in the case of dioxins, manufacturers have worked in concert with EPA to reduce levels of toxins about which there is broad agreement.
Research into toxicity is complex and costly because deleterious effects may not be evident for years. Studies of polluted sites and subsequent cleanup efforts are time-consuming and very expensive. This vital work is beyond the capacity of individual states.
Scott Pruitt, the newly appointed head of the EPA, proposes disabling cuts to the staff and programs of the EPA. Does he discount environmental science altogether? Is he opposed to any government involvement in safeguarding the public's health? Does he believe that chemical manufacturers will always act in the public's interest? I consider his proposals indefensible.
Contact Clif Cleaveland at ccleaveland@timesfreepress.com.