[Pharmwaste] Worms bioconcentrate PPCPs

Tenace, Laurie Laurie.Tenace at dep.state.fl.us
Thu Feb 21 10:43:15 EST 2008


http://pubs.acs.org/subscribe/journals/esthag-w/2008/feb/science/nl_earthworm
s.html

Worms bear sludge load
Researchers find that perfumes and drugs bioconcentrate in earthworms
collected from soils treated with biosolids and manure.

Pharmaceuticals and personal care products (PPCPs) end up in the tons of
solid sludge left behind by wastewater treatment processes. Those so-called
biosolids are often repackaged and sold as fertilizers for both industrial
and small-scale agriculture. In a new survey, published in ES&T (DOI:
10.1021/es702304c), researchers show for the first time that those compounds
can turn up in earthworms.

The findings illustrate the wide array of PPCPs that can be carried from
treatment facility to field. Biosolids provide "great value as sources of
organic carbon and nutrient compounds," says coauthor Edward Furlong of the
U.S. Geological Survey (USGS), but "you still have to understand the trace
constituents." The proof-of-concept study also demonstrates that worms are
taking up some of the compounds into their tissues and bioconcentrating them
there, with unknown effects, says study coauthor Dana Kolpin, also of USGS.

Bioaccumulation of PPCPs by worms is not entirely a surprise, according to
Stockholm University's Cynthia De Wit, who points to her own work looking at
PBDEs and other persistent compounds in earthworms. However, the new research
underscores that worms could serve as monitoring organisms, she says. Because
the worms seem to concentrate compounds that may be present at undetectable
levels in the soils, they can be "a sort of sentinel, or magnifying glass of
what's in the soil," she adds.

Kolpin collected worms and soil samples from three sites several times during
a growing season: a soybean field amended with biosolids (which were not
tilled into the soil) from a wastewater treatment plant, a corn field treated
with swine manure that was tilled into the soil, and a soybean field not
amended with biosolids or manure.

After the worms emptied their guts, whole-body analyses gave the team an idea
of what the creatures carried in their tissues. The worms' levels of some
PPCPs were several orders of magnitude higher than concentrations of the same
compounds in the soil samples. The scientists also found varying
concentrations of wood preservatives and PAHs in the amended fields; some
substances, including triclosan (an antimicrobial used in soaps) and the
synthetic musks galaxolide and tonalide, turned up at surprisingly high
levels.

Even the unamended field, which was to serve as a control site, had high
concentrations of perfumes and triclosan in some places. Nuria Lozano, a
visiting scientist at the U.S. Department of Agriculture (USDA), comments
that triclosan levels in particular were an order of magnitude higher than
those she has found in her own work. The result partly underscores how hard
it can be to find an uncontaminated site, says Cliff Rice, Lozano's colleague
at USDA. The authors conjecture that the source of these contaminants may be
nearby septic systems or surface runoff.

Rice notes that biosolids tend to clump together and sit atop soils for
months during dry spells if not tilled into the ground. As a result, the
team's second sample collection, after the biosolids were applied, "may be
more representative than the first," he says.

Tammy Jones-Lepp, a research chemist at the U.S. EPA Office of R&D
Environmental Chemistry Branch in Las Vegas, Nev., notes that a couple of the
results seem contradictory with regard to bioconcentration, with some
substances appearing at much higher levels in the soils than in the worms.
She would like to have seen "blank" worms, raised in a clean test plot for
comparison with the wild worms from the fields. Still, Jones-Lepp says,
"there definitely is a bioconcentration factor going on," and the data raise
more questions, for example, as to whether the worms break down the
contaminants in soils in which they live.

Robert Hale of the Virginia Institute of Marine Science observes that
earthworms are mobile and that the most bioaccumulative chemicals likely
remain near the surface. "Where were the worms prior to sampling?" he asks,
raising the issue of "habituation" and possible avoidance behaviors by the
worms. The fields were treated only once, whereas in practice, biosolids may
be applied many times to the same plot, he notes. "The field study
incorporates many variables, so simple interpretation is difficult."

Lead author Chad Kinney of Colorado State University Pueblo says this "one
project is leading to more questions." Now that the researchers know that
earthworms pick up PPCPs and other anthropogenic indicator compounds from
biosolids, they plan to take the "next logical step," he says, to see what it
means for the worms-and for other organisms that might eat them. -NAOMI
LUBICK

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 

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

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




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