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Aquatic Science Gets Hormonal

Photo by Chris J. Benson.

Products and packaging can release endocrine disrupting chemicals into the environment.

The good news is that people in Duluth are not dying of cholera like they did in the mid-1800s and that the Cuyahoga River isn’t in flames like it was in 1969. The good news is that water quality in the U.S. has improved to the point where
scientists are moving from worrying about eagle-killing levels of DDT to worrying about the sex life of fish.

The bad news is that what environmental scientists have come to understand about the sex life of fish swimming in water tainted by endocrine disrupting chemicals (EDCs) is provocative enough to concern the National Institute of Health and factor into the first-ever scientific statement issued by the Endocrine Society, a professional organization that has been convening since 1917.

In its 50-page statement issued in 2009*, the Endocrine Society concluded "results from animal models, human clinical observations, and epidemiological studies converge to implicate EDCs as a significant concern to public health."

The report documents evidence that EDCs can impair male and female reproduction as well as interfere with normal breast development in women. It links EDCs to cancer, obesity, and glandular and metabolic complications. According to the Endocrine Society, no endocrine system is immune to EDCs and the effects of EDCs may be transmitted to future generations through germline epigenetic modifications or from continued exposure of offspring. The endocrine system regulates body functions like metabolism, growth, development, tissue function and mood through glands that produce hormones. Hormones measure in parts-per-trillion, making them rare as well as an essential body element. Hormone mimics can confuse the chemical codes with only a whisper of a presence, altering the internal workings of the body. EDCs are hormonally active agents that mimic hormones. They effectively throw a monkey wrench into otherwise normal health by binding to hormone receptors or interfering with typical hormone responses. Endocrine disrupters can halt or stimulate hormone production and change the way hormones travel.

Minn. Sea Grant-funded journal reprints about endocrine disrupting chemicals from 2009-present

JR 593. Schoenfuss, and H.L., J.T. Levitt, R. Rai, M.L. Julius, D. Martinovic. 2009. Treated wastewater effluent reduces sperm motility along an osmolality gradient. Arch Environ Contam Toxicol 56:397–407. DOI 10.1007/s00244-008-9219-1 www.springerlink.com/content/8812264tn118646w

JR 563. Garcia-Reyero, N., I. Adelman, D. Martinovic, L. Liu, and and N.D. Denslow. 2009. Site-specific impacts on gene expression and behavior in fathead minnows (Pimephales promelas) exposed in situ to streams adjacent to sewage
treatment plants. Proceedings from MCBIOS Conference. www.biomedcentral.com/1471-2105/10/S11/S11

New! JR 591. Garcia-Reyero, N., C.M. Lavelle, B.L. Escalon, D. Martinovic, K.J. Kroll, P.W. Sorensen, N.D. Denslow. 2011. Behavioral and genomic impacts of a wastewater effluent on the fathead minnow. Aquatic Toxicology 101: 38-48.

New! JR 592. Lavelle, C. and P.W. Sorensen. 2011. Behavioral responses of adult male and female fathead minnows to a model estrogenic effluent and its effects on exposure regime and reproductive success. Aquatic Toxicology 101: 521-528.

New! JR 594. Schoenfuss, H.L., D. Martinovic, and P.W. Sorensen. 2011. Effects of exposure to low levels of water-borne 17b-estradiol on nest holding ability and sperm quality in fathead minnows. Journal of Contemporary Water Research and Education 120: 49-55. www.ucowr.org/updates/pdfn/V120_A6.pdf

For years Minnesota Sea Grant has funded research examining how EDCs affect fish reproduction. The latest suite of articles coming from this research suggests that exposing male fish to the effluent discharged by sewage treatment plants feminizes them to some extent.

Estradiol, the predominant female sex hormone and the major estrogen in humans, is found in effluent at low levels. When normal male fathead minnows live in effluent-levels of estradiol for 21 days, they start producing the typically female protein vitellogenin (JR 594) and fail to compete with males from untainted waters (JR 592). Male fatheads living in a more complex brew (effluent from a sewage treatment plant in St. Paul, Minnesota) also produce vitellogenin and lose their ability to fight for and defend a nest. Living in this effluent alters the way their genes determine their reproductive and metabolic activities (JR 591).

Other results indicate that minnows caged for a mere 48-hours downstream from five different sewage treatment plants exhibit changes in gene expression and behaviors in a site-specific way (JR 563).

Asking the question, "How does effluent affect the mobility of goldfish sperm?" Sea Grant researchers found that sperm activation and motility suffers as the effluent concentration nears 100 percent.

Curiously, they also found that Mississippi River water could sometimes have a pure effluent-like crippling effect on goldfish sperm (JR 593).

As the co-authors of “Behavioral and genomic impacts of a wastewater effluent on the fathead minnow” concluded, “While the gene expression signature from effluent-exposed fish shared some elements with estrogen and androgen signatures, overall it was different, underscoring the complexity of compounds present in sewage and their different modes of action.” (JR 591)

Making a giant leap from Sea Grant’s estrogen and effluent studies to human health would be foolhardy. However, the extent to which EDCs are woven into the fabric of society is undeniable. They’re in medicines, baby pacifiers, and food. They’re in personal care products, packaging, and flame-retardants. They flow from pulp mills, agricultural endeavors, sewage treatment plants, and landfills.

Scientists have identified the EDC problem in a way that has made the challenge of combating it much more personal. Are you willing to seek out and maybe spend more money on products and services that contain fewer hormone mimics, and practice safer disposal of products that contain EDCs? Are you willing to bet that the sex lives of fish have nothing to do with you?

Recent audio episodes concern endocrine disrupting chemicals:

Listen to The Sea Grant Files www.seagrant.umn.edu/radio/sgf.

  • Popular Chemicals Afflict Fish (interview with Gary Ankley, EPA researcher)
  • Frogs and Water Chemistry: Part 1 (interview with Pat Schoff, University of Minnesota Duluth research associate)
  • Frogs and Water Chemistry: Part 2 (interview with Pat Schoff, University of Minnesota Duluth research associate)

* Diamanti-Kandarakis, E., J.P. Bourguignon, L.C. Guidice, R. Hauser, G.S. Prins, A.M. Soto, R.T. Zoeller, and A.C. Gore. 2009 Endocrine-Disrupting Chemicals: An Endocrine Society Scientific Statement. Endocrine Reviews 30(4):293-342 www.endo-society.org/journals/ScientificStatements/upload/EDC_Scientific_Statement.pdf

By Sharon Moen
June 2011

Return to June 2011 Seiche

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