Endocrine Disruptors: Latest Threat to Surface Waters
By Cornelius B. Murphy, Jr.
The United States has one of the world’s best systems for both wastewater and potable water treatment and distribution; however, that doesn’t mean we are without challenges.
We are familiar with the impact of various synthetic organic chemicals on the human endocrine system and their ultimate stress on human reproduction, growth and/or development. The endocrine disruptors mimic or block hormones and disrupt the way the body normally works through the functional impairment of the endocrine glands: pituitary, thyroid, adrenal, thymus, pancreas, ovaries and testes. Each of the endocrine glands releases hormones that serve as messengers to various areas of the body to control essential functions.
Environmental-based endocrine disruptors, including some of the PCB arochlors, dioxin, DDT and other synthetic organic compounds that we might inhale, eat or otherwise have contact with, are seen as contaminants when they get into our water in undetermined amounts. These compounds mimic our body’s natural hormones, causing the body to overreact or react at inappropriate times.
It is now recognized that humans can be exposed to endocrine disruptors through drinking water. Endocrine disruptors have been detected in both ground and surface water. Under the Safe Drinking Water Act, there is no requirement to analyze for the presence of endocrine-active chemicals such as bisphenol A, alkylphenols, ethinylestradiol and others in our treated drinking water. Likewise, there is no such requirement under the Clean Water Act to test for these chemicals in our wastewater.
In our surface waters, the most significant sources of endocrine-active chemicals most likely are the effluent from municipal wastewater treatment plants. Many estrogenically active compounds, such as estradiol and derivative compounds, are treated to levels of 80 percent or greater by secondary treatment of municipal wastewater. 
That still leaves significant concentrations of endocrine-active chemicals that are discharged to receiving waters via treated municipal wastewater. These and other sources of these compounds have significant impacts on the aquatic system including, but not limited to, reproductive impacts on fish populations and invertebrates.
Municipal wastewater is clearly not the only source of endocrine-active chemicals. Hormones are introduced into livestock feed to increase meat production. Significant amounts of these growth hormones end up in surface water systems from storm water that flows across agricultural land.
We need to be concerned that our potable water might be contaminated at low levels by medications, antibiotics and hormones that we take in hopes of improving our health, and by hormones used in agriculture.
It is vital that we better understand the concentrations of these contaminants in our municipal, industrial, and agricultural wastewaters and storm water. We need clearer information about the concentration and distribution of these endocrine-active chemicals in our surface and ground waters. More resources need to be dedicated to monitoring our receiving waters, wastewater, storm water and drinking water.
We need to implement the recommendations of the Endocrine Disruptor Screening and Testing Advisory Committee and develop a strategy to mitigate the risk to human health and the environment. The U.S. Environmental Protection Agency has received $131,514,000 since 1999 to screen nearly 89,000 synthetic organic chemicals for endocrine disruption activity.  This represents only a beginning in our attempt to understand this issue and its impact on human health and the health of our biosphere. This pervasive human health problem deserves more attention.
1. Ternes TA, Stumpf M, Mueller K, Haberer K, Wilken R-D, Servos M: Behavior and occurrence of estrogens in municipal sewage treatment plants — I. Investigations in Germany, Canada and Brazil” Sci Total Environ 1999, 225: 81-90
2. Reference: Minn Post “Endocrine disruptors in water: Minnesota is ahead of Wis. in testing” 4/22/13, page 4 of 7