[Pharmwaste] HRT-related horse estrogens in waste water

[Tenace, Laurie]

http://www.environmentalhealthnews.org/ehs/newscience/horse-estrogens-from-hr
t-active-in-fish/

(the picture with this article is all wrong. Mares used for collection of
urine to create humane hormone replacement are kept in small stalls and
catheterized to collect their urine during pregnancy. When they deliver, the
foals are removed from their mother and the horse is re-bred as soon as
possible. They don't spend any time running free in fields of grass
http://www.friendsofanimals.org/programs/domestic-feral/horses/pmu.htm -
Laurie)

HRT-related horse estrogens in wastewater may feminize fish. 
Jun 09, 2009 

Tyler, CR, AL Filby, LK Bickley, RI Cumming, R Gibson, P Labadie, Y Katsu, KE
Liney, JA. Shears, V Silva-Castro, H Urushitani, A Lange, MJ Winter, T Iguchi
and EM Hill. 2009. Environmental health impacts of equine estrogens derived
from hormone replacement therapy. Environmental Science & Technology
doi:10.1021/es803135q.
 
Some horse estrogens used in hormone replacement therapies make their way
from people to wastewater and into fish where they may contribute to the
feminization of the animals, reports a study from England. Laboratory tests
showed the hormones - one of which was more potent than human varieties - can
turn on estrogen hormone systems in fish at very low concentrations. This is
the first time scientists report that HRT-related horse estrogens in water
coming into and leaving sewage treatment plants are estrogenic in fish.

What did they do?
 A British team analyzed levels of six horse estrogens commonly found in HRT
in water arriving to and being discharged from four  wastewater treatment
plants in England. Two estrogens - equilin (Eq) and equilenin (Eqn) - and
four of their metabolites were examined.

The researchers exposed fish to several horse estrogens and then examined
blood, gonads and livers for responses. They also measured estrogen levels in
the bile of exposed fish to gauge if and how much of the hormones the fish
were taking up from the water.

An assay was used to compare the estrogenic potency (the concentration
required to activate the estrogen receptor) of the compounds relative to the
human estrogen (17B-estradiol). The hormones were tested with both the human
estrogen receptor and the estrogen receptor of a fish species called a roach.



What did they find?
Of the six horse estrogens screened, only  equilin (Eqn) and metabolite
17beta-dihydroequilin (17B-Eqn)  were detected at nanogram per liter (ng/L)
concentrations in the influent and effluent. Eqn concentrations were higher
than 17B-Eqn, but both were found at lower levels after treatment. 

When fish were exposed to the horse hormones, Eqn and 17B-Eqn were found
concentrated in the bile. Both hormones also increased the blood levels of
the egg protein vitellogenin in the fish. The higher the exposures, the more
vitellogenin was measured. 

All of the horse hormones had some estrogenic reactivity with human and fish
estrogen receptors.  Additionally, all six compounds activated genes in the
fish through the estrogen receptor. Furthermore, exposures to concentrations
as low as 0.6 ng/L stimulated estrogenic activity in the fish.

When tested with the the human estrogen receptor, every horse estrogen was
less potent than the main human estrogen, 17beta-estradiol. Eqn was only 15
percent as potent as estradiol, while the horse hormone metabolite 17B-Eqn
was 77 percent as potent as human estrogen.

When the compounds were tested on the fish estrogen receptor, 17B-Eqn was
"35-fold more potent" than estradiol while the rest were weaker. Eqn was 25.6
percent as potent as estradiol.

What does it mean?
Estrogens derived from horse urine and used in hormone replacement therapies
are another source of estrogenic compounds in wastewater. This is the most
thorough report to date of the environmental levels and estrogenic effects of
these hormones.

The two main compounds measured in the inflow and outflow of treatment plants
were mostly less potent than the human estrogen estradiol. However, they
accumulated in fish, sparked egg protein production (an estrogenic marker)
and triggered human and fish estrogen receptors at low levels.

Overall, the results show that estrogens from HRT can make their way through
the sewage treatment process, into natural waterways and concentrate in the
fish that live there.

The equine estrogens were also capable of producing estrogenic responses in
the exposed fish and in lab assays. These results clearly show their
potential to affect fish and may be contributing to fish feminization
reported in prior studies.

While the 17B-Eqn concentrations tested in the study  is higher than
typically found in effluents (about 0.10 ng/L), the understanding that
exposures to environmental estrogens act additively makes this yet another
potentially harmful compound in the environment.

The environmental health affects reported in this study "should perhaps be
considered when weighing up the risks and benefits of HRT for women," the
authors' conclude.


Context
Concerns about hormones in the environment are not new and are well
documented (Halford 2008). Municipal wastewater treatment plants discharge
hormones used in birth control pills. Reports of feminization of wildlife
living in waters receiving such discharges is also well known.

Menopause is the time in a woman's life when menstruation cycles wane in
preparation for the reproductive system  to shut down. Typically, women are
between the ages of 45 and 55 when the changes occur.  Levels of estrogen and
other hormones that guide monthly mensus cycles decrease and level off as
menstruation stops.

Women take hormone replacement therapies (HRT) to maintain estrogen and
progesterone hormones at levels similar to premenopause levels. This helps
control symptoms such as hot flashes and mood swings. While the hormones have
health benefits, they are also linked to cancer and other ailments. Longterm
HRT studies find protective benefits against bone loss as well as higher
risks of cancer, heart disease and stroke (Womens Heatlh Initiative
Scientific Resources). 

Horse (equine) hormones are commonly found in HRT taken by women during and
after menopause. While HRT seems to be decreasing amidst concerns about
breast cancer and heart disease risks, it is still used by approximately 17
percent of women over 50 years old in the US.

Unlike birth control pills, few studies have examined the environmental
impacts of estrogen hormones used in HRT. One prior study found the estrogens
can accumulate in fish bile (Gibson 2005). Very little to nothing is known
about their environmental distribution and effects on wildlife.




Laurie Tenace
Environmental Specialist
Waste Reduction Section
Florida Department of Environmental Protection
2600 Blair Stone Rd., MS 4555
Tallahassee FL 32399-2400
P: 850.245.8759
F: 850.245.8811
Laurie.Tenace at dep.state.fl.us 

Mercury: http://www.dep.state.fl.us/waste/categories/mercury/default.htm 

Unwanted Medicine:
http://www.dep.state.fl.us/waste/categories/medications/default.htm



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