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Endocrine Disruptors

March 27, 2008                           

Contents:

• Introduction
• Environment Canada
• USEPA
• ELA- Freshwater Institute, DFO, Canada
• EDCs in the effluents of STPs (sewage treatment plants)

• Enlightening articles in the North American media

Intoduction

Endocrine disrupting compounds (EDC's) are chemicals that either mimic endogenous hormones, interfere with pharmacokinetics or act by other mechanisms.

"An exogenous agent that interferes with the production, release, transport, metabolism, binding, action or elimination of natural hormones in the body responsible for the maintenance of homeostasis and the regulation of developmental processes."

This definition includes the general types of mechanisms for endocrine disruptors. Such adverse effects as compromised reproductive fitness, functional or morphological birth defects, cancer and altered immune functions, among others, have been reported in the scientific press for wildlife, in vitro, and in vivo studies. These findings have received considerable attention in the popular press, led to government regulatory actions and expanded research in Europe, Asia and the U.S. Many suspected endocrine disruptors (ED's) are high-volume, economically important chemicals, a factor that magnifies the need for resolution of the scientific issues.

Environment Canada

"Canadian scientists are among the world’s leaders in studying reproduction and developmental effects on wildlife populations. Their research, particularly in the Great Lakes, has been vital in bringing international attention to the issue. Recently, scientists have seen a variety of endocrine-related effects in fish and wildlife in many parts of the world, including Canada. Fortunately, in many of these cases, action has been taken to reduce exposure, and at least some wildlife populations have recovered."

Some examples of endocrine-related effects in wild populations:

deformities and embryo mortality in birds and fish caused by exposure to industrial chemicals and organochlorine insecticides;

impaired reproduction and development in fish exposed to effluents from pulp and paper mills;

abnormal reproduction in snails exposed to antifouling substances applied to the exteriors of ships;

depressed thyroid and immune functions in fish-eating birds;

feminization of fish near municipal effluent outlets

 Endocrine Disruptors and Hog Manure

USEPA

 Ecological Exposure Research Division

 Endocrine Disruptors Research Initiative

 Vitellogenin Gene Expression in the Male Fathead Minnow as an Indicator of Exposure to Endocrine Disrupting Chemicals (EDCs) in an Aquatic Environment

ELA- Freshwater Institute, DFO, Canada

Endocrine Disrupting Chemicals (EDC's):

"Considerable evidence exists that aquatic organisms are being exposed to, and impacted by, a wide range of compounds that mimic hormones. Fish exposed to these compounds often exhibit an array of responses including depressed circulating sex steroid levels, reduced gonad size and fecundity, and males have become feminized. One of the most sensitive and common tools used to assess exposure to endocrine disrupting chemicals (EDCs) with estrogenic activity is the presence of vitellogenin (VTG), an egg yolk protein precursor, in the plasma of male fish. Recent studies have shown elevated plasma VTG in male fish downstream of sewage treatment plants."

Estrogen Addition to ELA Lake 260 (Hormone Mimics)

EDCs in the effluents of STPs (sewage treatment plants)

"Of ultimate concern in any treatment process is an assessment of the treatment success in elimination of the toxic action of the parent pollutant. Mineralization of the pollutant would require extended UV treatment times and in many cases would not be practical. Thus, as with any oxidation process, breakdown products will be formed. The relative threats of these products, as compared to their parent compounds, must be assessed through toxicological testing.

The EDCs used in this study included bisphenol A (BPA), ethinyl estradiol (EE2), and estradiol (E2) and were chosen because of their environmental relevance and frequent human exposure. All three have been found in streams throughout the United States, England, and Japan. Also, each compound is relevant in terms of human exposure.

BPA is a plasticizer used in the production of numerous plastic articles , including the plastic lining of food storage cans and polycarbonate babies' bottles. EE2 is one of the most commonly used active ingredients in oral contraceptives, and E2 is the natural female hormone, estrogen.

Because many EDCs can only be partially removed with conventional water treatment systems, there is a need to evaluate alternative treatment processes. The degradation of these EDCs using monochromatic and polychromatic UV radiation from low- and medium-pressure lamps, respectively, with and without the addition of H₂O₂ was evaluated. Kinetic parameters were developed in an effort to model the destruction of EDCs by UV and UV/H₂O₂ in a variety of water quality matrices.

The polychromatic medium-pressure (MP) UV radiation source was more effective for direct photolysis degradation as compared to conventional low-pressure (LP) UV lamps emitting monochromatic UV 254 nm radiation. However, in all cases the EDCs were more effectively degraded utilizing UV/H₂O₂ advanced oxidation as compared to direct UV photolysis treatment."

Enlightening articles in the North American media

• Male Bass in Potomac Producing Eggs; October 15, 2004
  
• Debate over bisphenol A; July 04 2007
  
• Estrogen threatens minnow manhood; May 22, 2007
  
• Awwa Research Foundation press release; September 12, 2007
  

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