Expert answer:Environmental Estrogens What is the problem potent
Solved by verified expert:Environmental estrogen is the term for any of a group of synthetic substances found in the environment that function in a similar way to estrogen.What is the problem, potential dangers, and evidence of these chemicals and there impact. Finally, include a paragraph with your reaction to this information—alarmed, overwhelmed, not concerned, etc
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Environmental Health Perspectives Volume 114, Number 5, May 2006
Forum
A Headache for Water Treatment
Acetaminophen is turned into at least two toxic compounds by chlorination treatment,
researchers report in the 15 January 2006 issue of Environmental Science & Technology,
raising concerns about the fate of this and other pharmaceuticals that end up in water
supplies. Acetaminophen is one of the most widely used over-the-counter painkillers in
the world–in the United States alone, some 37,000 metric tons are produced each year,
says coauthor Mary Bedner, a research chemist at the National Institute of Standards and
Technology. “Some of this is reaching the environment,” she says, “but no one really
knows what happens to it or what effect it might ultimately have on ecosystems or
people.”
Remedy or pain? The presence of toxic metabolites in water supplies makes you wonder.
image: Christian McCarty/ShutterStock
Reports of acetaminophen in European rivers have appeared since the 1990s, and in the
15 March 2002 issue of Environmental Science & Technology a USGS team reported
detecting it in nearly a quarter of the water bodies it sampled. “It gets there through
wastewater [i.e., via human excretion] and in some cases through poor disposal
practices,” says Nick Voulvoulis, a senior lecturer in natural sciences at Imperial College
London. Only 22% of Britons and just 1.4% of Americans return unwanted medicines to
pharmacies, says Voulvoulis. More than 35% of U.S. nonreturners flush unused drugs
down the toilet, while most British drugs end up in landfills, from which they can leach
into water bodies.
Concerned that acetaminophen’s structure renders it likely to react with chlorine, Bedner
and colleague William MacCrehan used reversed-phase liquid chromatography to follow
its interaction with the chlorinating agent hypochlorite. Under simulated treatment
conditions in samples of distilled water and wastewater, 11 new compounds were formed
from acetaminophen within an hour, the time the reactants would likely be in contact at
any plant. Among them were 1,4-benzoquinone (a mutagen) and N-acetyl-pbenzoquinone imine (a hepatotoxicant also produced during acetaminophen metabolism
that is responsible for overdose deaths). Together, these compounds represented the fate
of nearly 27% of the original drug concentration.
“Fortunately, these are unstable compounds, especially in the presence of sulfite, which is
sometimes used to dechlorinate treated water, so they are unlikely to persist long in the
environment,” Bedner says. “However, they could accumulate where treated wastewater
is returned to rivers, and the effects of resupply over long periods are unknown.” The
results also raise the question of what other drug-derived toxicants are out there, she says.
“This work shows we need to know much more about the fate of the drugs that
contaminate our water supplies,” says Damià Barceló, a professor of environmental
chemistry at Barcelona’s Centre for Research and Development. “We also have to look
for what they turn into. Searching only for the original compounds themselves will not
reveal all the dangers these contaminants may pose.”
Environews Focus
A 470
VOLUME
114 | NUMBER 8 | August 2006 • Environmental Health Perspectives
Focus
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The Apple Bites Back
The Apple Bites Back
Claiming Old Orchards for Residential Development
A
s the U.S. population continues to grow,
acres per year—a 51% increase over the average
increasing demand for housing and related
annual rate reported for the preceding decade.
community resources means more land is being con-
Naturally, many of these areas were routinely
verted from agricultural uses to residential applica-
treated with pesticides and other chemicals during
tions. According to the revised 1997 National
their agricultural lifetimes. Although this legacy has
Resources Inventory conducted by the USDA
been problematic in a wide variety of land conver-
Natural Resources Conservation Service, more than
sion scenarios, one in particular seems to have
6 million acres of American farmland were convert-
attracted the attention and concern of environmen-
ed to developed uses between 1992 and 1997. That
tal officials and property buyers in several states
is an annual conversion rate of roughly 1.2 million
across the country: the residential development of
Environmental Health Perspectives
• VOLUME 114 | NUMBER 8 | August 2006
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The Apple Bites Back
historic orchard properties. In state after
state, these old orchards (which most often
produced apples, but also peaches, cherries,
pears, and other tree crops) are metamorphosing into highly desirable subdivisions—desirable, that is, until it emerges
that the soil beneath the feet of the proud
new residents may be contaminated with
lead and arsenic. These toxic by-products
are left from the days before DDT and
before organophosphates, when arsenical
pesticides, particularly lead arsenate (LA),
were the treatment of choice to prevent the
ravages of insect damage.
They Loved LA
LA was introduced in 1892 in Massachusetts for use against the gypsy moth.
Two other arsenical pesticides (copper
acetoarsenite, known as “Paris green,” and
calcium arsenate) also were in use, although
LA largely replaced them in the 1930s due
to lower cost, greater efficacy, and lower
phytotoxicity. Even though arsenic residue
was recognized as a problem as early as
1919, LA was the most widely used pesticide in the nation—recommended by the
USDA and applied to millions of acres of
crops—until the late 1940s, when DDT
(considered at the time to be safer and more
effective) became available. LA continued
to be used in some locations into the 1970s,
and was ultimately banned in 1988.
LA was perhaps most commonly
applied in apple orchards, due to its excellent control of the codling moth, a major
apple pest. Today, apple orchard properties
that were in production during the heyday
of LA use are the focal point of environmental concerns; given the nature of the
pests peculiar to orchard crops, growers
tended to apply the chemicals frequently
and in high concentrations, often over
many years. “In some cases, they dusted the
apple trees or peach trees every week,
whereas most field crops may have had one
A 472
discrepancy apparently
arose from a portion of the
arsenic in the disturbed
field having been mobilized and removed by
surface water. Renshaw
found arsenic in the sediment of a nearby stream in
amounts that very closely
matched the arsenic missing from the tilled field.
“The implication from
our study,” says Renshaw,
“is that if you’re not realYou spray, you pay? Spraying of arsenical pestily careful about erosion,
cides on apple orchards was routine from the
late 1800s through the 1940s. Lead arsenate was
you’re going to end up
not banned, however, until 1988.
sending a lot of arsenic
down into the stream
or two applications during the growing seachannel.” To date, researchers have seen no
son,” says Kevin Schick, a bureau chief with
evidence of direct health effects in humans,
the Site Remediation and Waste Manageanimals, or plants exposed to this streamment Program in the New Jersey Departbound arsenic. However, more study is
ment of Environmental Protection.
needed to fully understand the ramificaLA and the other arsenical pesticides
tions—if any—of the mobilization.
were designed to be persistent, and it is that
How Dangerous?
persistence that is causing environmental
The potential danger posed to human
contamination problems decades after their
health by lead and arsenic contamination
use ended. “These chemicals have just
in historic orchards is a complex issue,
tremendously long half-lives in the ground,”
fraught with scientific uncertainties and
says North Carolina state toxicologist Ken
competing interests. Arsenic is a known
Rudo. “They bind very tightly to the soil.”
human carcinogen. Exposure to lead, espeOnce LA reached the soil through overcially prenatally and in childhood, can lead
spray, spillage, rainfall wash-off, or simply
to neurological damage. There is no doubt
fallen fruit and leaves, the lead arsenate
that excessive exposure to either substance
underwent hydrolysis, separating into lead
can adversely impact health, but in this
and arsenic bound to organic particles in the
case any risks are almost exclusively longsoil. The lead, being poorly soluble, was
term—virtually no instances of acute
immobilized, typically within the top 12 to
adverse health effects have been document18 inches of topsoil. The fate of the arsenic
ed in people living on historic orchard
was similar, but a bit more complicated.
properties.
“Arsenic, as arsenate, even though someRegulatory agencies such as the EPA
what sparingly soluble, is soluble, and it will
and state health and environmental departmove in water,” says Washington State
ments determine allowable levels of chemiUniversity soil scientist Frank Peryea. “I’ve
cals in soils and water based upon formulas
seen some sites where almost all of the
that take into account criteria such as toxiarsenic is still in the topsoil, in the tillage
city, exposure, and naturally occurring
zone, and I’ve seen sites where I’ve measured
background concentrations of the chemiarsenic movement as deep as a meter or so.”
cals. For carcinogens such as arsenic, the
Carl Renshaw, a hydrogeologist at
calculations are based upon the amount of
Dartmouth College, published a study in
a chemical that is predicted to result in 1
the January/February 2006 issue of the
additional cancer case occurring in 1 milJournal of Environmental Quality showing
lion people exposed over their lifetimes.
that arsenate in the soil can be remobilized
But there is some flexibility in the standards
by being disturbed. He compared two
based on local conditions and practical confields in the same historic New Hampshire
siderations. In New Jersey, for example,
orchard. One field had never been diswhere background arsenic concentrations
turbed, whereas the other had been tilled
are often high, the criterion for residential
and replanted in the early 1990s. “What
soil cleanup is set at 20 ppm—50 times the
we found was that in the field that had
EPA’s level of 0.4 ppm.
been replanted, there was somewhat less
In historic orchard properties, cleanup
arsenic on it than in the undisturbed field,”
action is often triggered when a so-called
he says.
“hot spot” is discovered—typically an area
Given the assumption of virtually idenwhere the pesticides had been mixed and
tical application rates over the years, the
VOLUME
114 | NUMBER 8 | August 2006 • Environmental Health Perspectives
Library of Congress
Focus
Gary Gilardi/ShutterStock
Focus
|
The Apple Bites Back
loaded or stored, and where repeated spills
The risks involved may be modest and
forces examine the problem and issue recor disposal of excess materials may have
long-term in most cases, but low risk is not
ommendations and guidelines.
occurred. The contaminant concentrations
the same as no risk, and regulatory agencies
Wisconsin is likely to convene a similar
in those hot spots can be significantly highacross the country are finding themselves in
task force later in 2006, according to
er than in the tree crop areas. But locating
a thorny situation as more and more conBowman. “We want to develop a protechot spots after many decades can be very
taminated historic orchard properties are
tive, economical, and practical strategy to
difficult.
developed. They are caught between their
address potential residues of lead and
The ATSDR is often called in to anaduty to protect public health and the enviarsenic in soils related to historic orchard
lyze the health risks at contaminated hisronment, and the fact that the risks preuse,” she says. “The charge of the task force
toric orchard properties. “We look at the
sented by most of these properties pale in
would be to evaluate the health and envicontaminants, the concentrations, the
comparison to those associated with other,
ronmental impacts, and [also evaluate]
pathway, how long [residents] are exposed
more acute contamination sites, such as
what kind of alternatives and strategies we
to it—all of the different aspects of an
lands near smelters or toxic waste dumps.
could put into place to limit exposure and
exposure,” says Robert Safay, an environNaturally, budgets are limited, and priorito educate and provide outreach to homemental health scientist with the agency.
ties must be set. Yet the orchard situation
owners and developers as to what types of
“For example, when you’re looking at lead
cannot be ignored, and several states have
precautions can be taken at these orchard
contamination in the soil, you’re primarily
been wrestling with how to deal with this
sites to mitigate any risk.”
concerned about young children playing
issue for several years.
What Can, Should, or Must Be Done
out in the soil.”
The sheer scope of the phenomenon
Because contamination can be spread over
In all but the most extreme cases, the
adds another layer to the challenge of how
large areas, remediation measures vary widely,
health risks of living atop contaminated histo most effectively deal with it. “The magdepending upon the level of contamination,
toric orchard soil are ultimately characterized
nitude of the problem is just staggering,”
the current or intended use of the property,
as very low and manageable. Exposure is the
says Peryea. Millions of acres across the
and state or local regulations. Each method
critical element. “The real issue here is direct
nation are involved. In the state of
has its advantages and its drawbacks, and
contact—you want to limit the direct conWashington alone, Peryea says, some
each site has its own unique circumstances
tact,” says Lori Bowman, director of the
188,000 acres are affected. In Wisconsin,
that will often dictate how, when, and even
Agrichemical Management Bureau in the
50,000 acres may be affected, and in New
if the situation will be dealt with.
Wisconsin Department of Agriculture, Trade,
Jersey, up to 5% of the state’s acreage is estiExcavation is the quickest and most thorand Consumer Protection. As Safay explains,
mated to be impacted by the historical use
ough remediation method. This involves
there must be a completed exposure pathway
of arsenical pesticides. Both New Jersey and
scraping up the contaminated topsoil,
for there to be even the potential for health
Washington have had multistakeholder task
effects. Ultimately, the
amount of risk depends on
the level of contamination
and the use of the land.
For the most part, residents are advised to limit
their direct exposure to the
soil if it’s unremediated
and to take simple measures such as wearing gardening gloves and wiping
their feet before entering
the house. Peryea says there
is little risk from eating
plants grown in this type of
soil, but advises that home
gardeners rinse off produce
before bringing it into the
home, then wash it again
with a detergent and scrub
brush to remove any
remaining soil particles,
paying particular attention
to rough vegetables like
broccoli and leafy vegetables like lettuce, which can
trap and retain dust. He
also advises paring root and
tuber crops such as potatoes, carrots, and radishes,
and not composting the
A blooming problem? Land that was once home to fruit orchards is now being turned into subdivisions, raising
peelings or other unused
questions about pesticides that may still be present in the soil and the potential risks they pose to residents.
plant parts.
Environmental Health Perspectives
• VOLUME 114 | NUMBER 8 | August 2006
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The Apple Bites Back
Soil blending is another alternative, and one that
is growing in popularity,
particularly when contaminant concentrations are
only minimally in excess
of actionable levels. This
involves bringing clean
soil to a site and mixing it
with the existing topsoil,
with the intent of reducing concentrations below
levels that require healthprotective actions. Although relatively effective,
blending can be a hit-ormiss operation. The main
reason is that operators
can’t always achieve 100%
blending, and it very
much matters where the
subsequent samples are
taken—even a few inches
can make a difference.
Sometimes it is necessary
to repeat the procedure,
which, of course, drives up
costs. Also, disturbing the
soil in this way could actually mobilize the arsenic,
as Renshaw’s research
showed. Regardless of its
shortcomings, however,
blending is an option
many states have chosen
in recent years.
In some instances, a
Soil survivors. Some experts recommend that homeowners have
simple solution can be
their soil tested for arsenic and lead, although no perfect method
adequate. “What seems
exists for remediating soil that is found to still be contaminated.
to do a good job of
reducing exposure in
hauling it away to an approved landfill, and
areas where people aren’t digging in the soil
replacing it with clean dirt. Realistically, says
is just to keep turf on it, or keep it vegetatPeryea, removal is the only way to eliminate
ed somehow,” says Peryea. At some sites,
risk, “but it’s very expensive.” Such total
simply moving the contaminated soil to
remediation can cost $1 million per acre or
another location on the site and capping
more. And it’s a huge undertaking. Peryea
it—for example, by burying it under a
does the math for 1 acre: “If you have conroadway—has been acceptable, although
tamination down to three feet, you’re looking
this option requires that a deed notice be
at getting rid of three acre-feet of soil—that’s
executed, so that all of the records of the
twelve million pounds of soil.”
sampling and disposal of the contamination
Capping, which involves simply putbecome part of the property’s permanent
ting a 12- to 18-inch layer of clean soil
title record.
over the contaminated soil, has been used
Thus far, other remediation methods
in some locations. However, this requires
have proven to be ineffective, impractical,
enormous amounts of clean dirt. Further,
or counterproductive on these sites.
capping cannot be considered a permaResearchers such as David Butcher, a pronent solution—plants will grow on the
fessor of analytical chemistry at Western
soil caps, their roots will penetrate the
Carolina University in Cullowhee, North
contaminated soil, and the vegetation will
Carolina, have explored the possibility of
eventually redistribute the lead and arsenic
phytoremediation of these properties, in
to the clean soil. Also, it is common for
which plants are used to suck the contamithe soil caps to be disturbed by construcnants out of the soil, after which the contion activities.
taminated biomass is destroyed. But this
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VOLUME
method, though effective in certain remediation situations, doesn’t appear to hold
much promise in lead- and arseniccontaminated orchard soils. Phytoremediation is quite slow, potentially taking
decades or longer to effectively remove contaminants. Butcher also was unable to discover a method of removing the lead from
the soil without the addition of other
chemicals (such as EDTA) to release the
tightly bound element.
One way to release the lead is by adding
phosphorus to the soil, but this also mobilizes
the arsenic. “That creates an even bigger
problem,” Peryea says. “If you get the arsenic
moving, and it moves down into the groundwater, cleanup becomes much more difficult
than trying to keep it in the topsoil.”
According to Peryea, you can scratch
microbial volatization as well. In that
method, native soil microorganisms are
stimulated to volatilize arsenic. The gaseous
arsenic can then be trapped. But for this
method to be effective, soils must be kept
quite wet. Many of the historic orchard
properties are well-drained, sloping sites,
where it would be difficult to ke …
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