[Pharmwaste] Wetlands reduce estrogens from swine wastewater

[Tenace, Laurie]

Wetlands reduce estrogens from swine wastewater
http://pubs.acs.org/subscribe/journals/esthag-w/2006/dec/science/bb_swine.htm
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Constructed wetlands can reduce natural estrogens in swine wastewater,
particularly in cooler weather. 
Wetlands are often referred to as nature's kidneys, because they readily
filter contaminants from water. Constructed wetlands, areas built to mimic
these natural swamps, help treat wastewater, usually by decreasing levels of
excess nutrients such as nitrogen and phosphorus. Research published today on
ES&T's Research ASAP website (DOI: 10.1021/es061268e) shows for the first
time that constructed wetlands also decrease natural estrogens-the female sex
hormones estrone (E1), estradiol (E2), and estriol (E3)-in animal wastewater.

 
Researchers measured estrogenic activity and specific estrogens from
wastewater before and after the water ran through these wetlands at North
Carolina Agricultural and Technical State University. Image Credit: USDA ARS
Nancy Shappell of the U.S. Department of Agriculture and researchers at North
Carolina Agricultural and Technical State University measured both estrogenic
activity-as E2 equivalents-and specific E1, E2, and E3 concentrations in
wastewater from the university's swine birthing and nursery site, known as a
farrowing facility.

The team used the facility's recirculation system to follow estrogens from
the barn, to a manure pit, to waste lagoons, and through the constructed
wetlands. The recycled water eventually was used to flush out the barn.

Scientists are concerned about estrogens in wastewater because these
hormones, both natural and synthetic, can disrupt reproductive function in
fish and wildlife. In a recent review, Samir Khanal and colleagues at Iowa
State University stressed the need to look at natural estrogens derived from
animal operations (Environ. Sci. Technol. 2006, 40, 6537-6546). Shappell's
study is one of the first to follow estrogenic activity from swine waste-in
the liquid phase-through a constructed wetland, Khanal says.

In the farrowing facility, estrogen concentrations were above 200 nanograms
per liter (ng/L) in the manure pit but consistently below 3 ng/L in the
wetland outflow. Because estrogen levels in the primary and secondary lagoons
were higher in November than in April or July, Shappell suggests that pumping
lagoon water through the wetlands may be especially effective in autumn,
presumably because estrogens break down more slowly at lower temperatures.
The water bypasses the wetlands in the winter, because of below-freezing
temperatures, but a storage pond holds enough gray water to flush the swine
house in the winter, according to coauthor Gudigopuram Reddy.

Khanal says he is concerned that the relative potencies for E1 used by
Shappell differ by a factor of 10 from those used by Furuichi and colleagues,
who followed estrogens in swine wastewater through a treatment process rather
than a constructed wetland (Environ. Sci. Technol. 2006, 40, DOI:
10.1021/es0609598).

Shappell used the E-screen assay, which measures estrogen-dependent
proliferation of a mammalian cell line. The assay used by Furuichi's team
relies on receptor-transfected cells, developed by adding estrogen receptors
to the cells by genetic engineering, and has a different treatment duration,
endpoint, and E2 concentration. Another commonly used assay uses
receptor-transfected yeast, Shappell indicates. The various estrogens do show
different potencies in different assays, and it's important to use a
physiologically relevant assay to measure estrogenic activity, she says.
"When you've played with receptor numbers and you get a signal, what does
that mean-physiologically?" she asks.

Shappell also determined actual concentrations of specific steroid hormones,
including E1, E2, E3, and testosterone, with analytical methods; she found
that E1 was the most persistent estrogen. Testosterone was not detected,
probably because the facility had very few mature boars.

Alice Layton, an expert in analytical detection of estrogens at the
University of Tennessee, Knoxville, has measured estrogen in both cattle and
swine waste (Environ. Sci. Technol. 2004, 38, 3567-3573). Layton applauds
Shappell's use of both a biological assay and chemical analysis and observes
that wetlands may be a low-cost solution to the problem of estrogens in
animal wastewater.

Shappell's coauthor Patrick Hunt notes that lagoon recirculation systems are
the norm in facilities that, overall, handle more than 10 million swine in
North Carolina, but he adds that wetland systems are uncommon in concentrated
animal feeding operations (CAFOs). According to Khanal, in addition to
concerns about estrogens in wastewater, the fact that many CAFOs store manure
in deep pits and eventually apply it to soil is a problem because it leads to
the potential for estrogens to leach into nearby waters.

Laurie J. Tenace
Environmental Specialist
Florida Department of Environmental Protection
2600 Blair Stone Road, MS 4555
Tallahassee, Florida 32399-2400
PH: (850) 245-8759
FAX: (850) 245-8811
Laurie.Tenace at dep.state.fl.us  
 
view our mercury web pages at: 
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