News & Politics

What’s In the Water We Drink?

Washington’s tap water meets or exceeds federal water-quality standards. But new, emerging pollutants are not removed by current water-purification technology. Could these be linked to alarming increases in obesity, diabetes, autism, and more?

Washington’s tap water, most of which comes from the Potomac River, meets or exceeds federal water-quality standards. But new pollutants have emerged that are not removed by current water-purification technology. Evidence suggests that the same contaminants that caused massive fish kills and deformities in recent years are linked to increases in obesity, diabetes, autism, cancer, and other disorders—and that medications and products we use every day might contribute to the problem.

Of all the natural resources in the Washington area, none is
more important than the potomac river. Besides the beauty and recreation
it provides, the area pulls nearly 400 million gallons of water a day out
of it—about 90 percent of our drinking water.

In some ways, the Potomac is cleaner today than it was 40 or 50
years ago. Back then, people were warned not to swim in the river or eat
fish from it; a tetanus vaccination was recommended for anyone who did
swim there. On many days, you could smell the Potomac before you saw

Improvements in wastewater treatment and conservation upgraded
the water quality of the river, which wends its way nearly 500 miles from
its origin in the Appalachian Plateau to Point Lookout, Maryland, where it
empties into the Chesapeake Bay. These efforts helped reduce major
pollutants—such as nitrogen and phosphorous from fertilizers, pesticides,
and soaps—that fed algae, rootless plant-like organisms that grow in
sunlit water. Algae blooms—rapid accumulations of microscopic algae in
water that can stretch for miles—deplete the water of oxygen and release
harmful toxins. They can virtually destroy a river if left to grow

Despite this progress, the river is not “clean.” In 2011, the
Potomac Conservancy, an organization that monitors the river, gave the
Potomac a grade of D, a drop from the D-plus the organization assigned it
in 2007. The conservancy noted that more than a third of the estimated
10,000 stream miles in the Potomac watershed are threatened or

Even so, the drinking water in the Washington area is closely
monitored and meets or exceeds every Environmental Protection Agency
water-quality standard. But as some of the old pollutants have been
removed from the river, new ones have emerged that are not removed by
current technology and may be harmful to human health, especially for the
very young.

This emerging class of contaminants, called
endocrine-disrupting compounds (EDCs), a variety of natural and manmade
chemicals from many sources, first came to light in a dramatic way in the
summer and fall of 2002 with massive fish kills along the south branch of
the Potomac River in West Virginia, about 200 miles upstream from DC. Some
of the contaminants are new, and others have been discovered recently
because new measuring techniques permit scientists to identify EDCs in
minute quantities.

Says Luke Iwanowicz, a scientist with the US Geological Survey:
“Many of these emerging contaminants have been off our radar until now,
mostly because we did not have the ability to detect them.”

Jeff Kelble ran a fishing-guide business on the Shenandoah
River, long considered one of the nation’s great fishing rivers,
especially for smallmouth bass. The Shenandoah empties into the Potomac at
Harpers Ferry, West Virginia. Kelble remembers when fish were so plentiful
that they fought over his lures—it wasn’t uncommon for the sport fishermen
he guided to catch 50 to 60 fish in a day, all of which Kelble released
back into the river.

That changed in the last week of March 2004, when Kelble
learned that fish kills had struck the north fork of the Shenandoah. From
his boat, when the murky spring water was clear enough, Kelble could see
redbreast sunfish and smallmouth bass lying motionless on the

Kelble didn’t know what to make of the scene. Had a poison been
dumped into the river? Was this fish kill related to the kills that had
struck the south branch of the Potomac in 2002 and 2003? Had a large
quantity of milk somehow found its way into the water from dairy farms
along the riverbank? Milk has a voracious appetite for oxygen and might
have robbed the river of enough to kill the fish, but when the river’s
oxygen levels were measured, they were normal.

Kelble tried catching fish but had little luck. Finally, he
hooked a smallmouth bass.

“We were excited at first,” Kelble says, “but when we lifted
the fish out of the water, we saw it was covered with red sores that
looked like cigar burns, and it had lost many of its scales. I’d never
seen anything like it. I have an engineering degree—I’m not a
biologist—and I had no idea what was wrong. We caught a few other fish,
and almost all had similar sores on them.” Kelble caught more fish.
“Between 50 and 60 percent of the fish had lesions,” he says.

Kelble, now a conservationist with Potomac Riverkeeper—a
nonprofit that monitors river quality throughout the four-state Potomac
watershed—estimates that in 2004 and 2005, 80 percent of the adult
smallmouth-bass population was wiped out in the Shenandoah River. The bass
are back, Kelble says, but he still sees sick fish.

Vicki Blazer, a fish pathologist with the US Geological Survey
(USGS), had the job of finding the cause of the fish kills. Working out of
Kearneysville, West Virginia, Blazer led a team onto the rivers to collect
dead and dying fish. Electroshocks in the water stunned the fish and
brought them to the surface, where Blazer’s group netted them and put them
into water buckets to which an anesthetic was added.

As Blazer dissected scores of smallmouth bass, she was
surprised to find that many of the males had characteristics of both
sexes. Some 80 percent of the male fish had oocytes—precursors of egg
cells produced by females—in their testes, a condition known as

Intersex among some species of fish is not unheard of but,
Blazer says, “you just don’t see this intersex phenomenon with

Ed Merrifield, president of Potomac Riverkeeper, calls the
river fish kills “the canary in the coal mine.”

Our region is not alone. Fish die-offs have been reported in
waterways throughout the United States. Last September, thousands of white
bass died in the Arkansas River with no clear explanation. Beginning in
2008, fish kills and fish with lesions were seen in the upper James River,
and lesions were seen on the Jackson and Cowpasture rivers in Virginia as
well. Intersex fish also have turned up in the Great Lakes and the
Mississippi River.

After wending its way some 200 miles from West Virginia, the Potomac River begins providing tap water for the Washington area near Great Falls. Photograph of Potomac River by Cameron Davidson.

Back at the lab, Blazer and her colleagues examined fish tissue
microscopically and discovered that some bass had bacterial infections
while others had fungal infections and still others were afflicted with
parasites. This finding led her to conclude that the plague killing the
fish wasn’t a toxin, a bacterium, or any single agent but resulted from
immune suppression that permitted opportunistic infections to flourish and
kill the fish.

“I think the fish kills were caused by the same chemicals in
the river water that are inducing intersex,” Blazer says. “Besides leading
to intersex, exposure to these chemicals, particularly estrogenic
hormones, depresses the immune system. The intersex occurs when the fish
are exposed to these estrogenic compounds at a young age.”

The study found that even bass with no signs of intersex
contained detectable levels of at least one endocrine-disrupting

Based on a USGS study published in Fish & Shellfish
in 2009, it appears that estrogenic compounds can lower
levels of hepcidin, an iron-regulation hormone found in mammals (including
humans), amphibians, and fish. Researchers believe hepcidin acts as a
first line of defense against certain disease-causing bacteria, viruses,
and fungi, which could explain why intersex fish and the fish kills
occurred at the same time.

Blazer and her colleagues published their findings in 2007 in
the Journal of Aquatic Animal Health. The report concluded that
intersex fish were “an important indicator of potential endocrine

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Blazer has found intersex fish on both the lower and upper
branches of the Potomac and on both forks of the Shenandoah. She says the
fish kills and intersex are most prevalent along the most agricultural
areas of the rivers—where dairy, cattle, and poultry businesses reside—but
that those are probably not the only sources of the chemical soup that
kills fish.

Kelble says he saw the highest mortality in the upper reaches
of the Shenandoah, which are close to the highest-intensity animal-feeding
operations. The nine-county Shenandoah Valley has more than 900 poultry
farms, with more than 87 million chickens in Rockingham County alone. On
several occasions, Kelble and others have seen cattle herds wading in
tributaries of the Shenandoah. The residue of human and animal excrement,
which holds both natural and manmade chemicals, is considered a
significant source of EDCs. The USGS reported that a higher incidence of
intersex fish occurred in streams that drain areas with intensive
agricultural production and high human population when compared with
non-agricultural and undeveloped areas.

Blazer also has found intersex fish in the Conococheague Creek
and the Monocacy River in Maryland. She believes the intersex fish are the
result of a “toxic soup” of endocrine-disrupting compounds that are
finding their way into the Shenandoah and Potomac rivers. This mixture
comes from homes, farms, and industry and has been added to the water for
years. When it reached critical mass, tens of thousands of fish

So what do dead fish 200 miles upstream from Washington have to
do with the quality of water we drink?

EDCs are a broad class of molecules that the EPA defines as
natural or synthetic agents that interfere with “natural blood-borne
hormones that are present in the body and are responsible for homeostasis,
reproduction, and developmental process.”

Natural hormones are secreted by endocrine glands into the
bloodstream and bind with specific cell receptors. Once bound, the
receptor carries out the hormone’s instructions, either modifying existing
proteins or directing the cell’s DNA to produce specific proteins. Because
EDCs mimic natural hormones and interfere with the endocrine system, they
can adversely affect normal growth, cognitive function, metabolism, and
reproduction in animals and humans.

Measuring their risk to human health has been hard because they
interact in complex ways at minute concentrations, both alone and in
combination with one another.

How they act in combination remains unclear. EDCs have been in
the environment in one form or another for more than 50 years and are
present in hundreds of millions of people worldwide. At last count, more
than 80,000 synthetic chemicals, mostly derived from petroleum and
vegetable sources, are in use today. The process of making these
synthetics involves toxic catalysts and reagents. Few of these 80,000
chemicals have been tested to determine what effect they have on

Individuals respond to EDCs in different ways, but one thing is
clear: Never before have humans had so many diverse synthetic chemicals
assaulting their bodies, a phenomenon some observers have called “the
largest uncontrolled science experiment in history.”

EDCs are present in many household items, such as
preservatives, plastics, cosmetics, and antibacterial soaps that contain
triclocarban, an endocrine disrupter that is flushed into wastewater and
ultimately into the river. Scented soaps and shampoos, hair-coloring
agents, skin creams, and sunscreen lotions contain them, as do some
spermicides, toilet papers, and facial tissues.

They’re also found in birth-control pills, hormone-replacement
therapies, and androgen-blocking or androgen-enhancing agents.
Chemotherapy and thyroid medications, antibiotics, and other prescription
drugs, some of which contain EDCs, enter the environment when they’re
excreted into wastewater and flushed down the toilet. Pharmaceuticals can
enter the water supply directly when unused pills are thrown

In 2008, the Associated Press published a series of stories
entitled “Pharmaceuticals Found in Drinking Water.” The AP conducted a
survey of water quality and found that pharmaceuticals were present in the
water systems of two dozen major metropolitan areas. Washington’s drinking
water contained evidence of six drugs, including carbamazepine (an
antiseizure medication), monensin (an antibiotic used in animal feeds),
sulfamethoxazole (an antibiotic often given for ear infections), ibuprofen
(Motrin and Advil), naproxen (Aleve), and caffeine. Philadelphia’s
drinking water contained evidence of 56 drugs and byproducts. The AP
estimated that the health-care industry flushes 250 million pounds of drug
waste down drains each year.

In tests conducted by the USGS between 2003 and 2005, trace
amounts of 26 chemical compounds were detected in Potomac River water,
including the herbicide 2,4-D, a component of Agent Orange, and
insecticides including DEET. Atrazine, a chemical commonly used in weed
killers, has been associated with intersex in amphibians and has been
found in many rivers, including the Potomac. Studies revealed that male
frogs exposed to atrazine produce eggs in their testes, the same
phenomenon seen with intersex fish.

River water goes through successive sedimentation basins before being treated in the filtration building at the Dalecarlia Reservoir and Treatment Plant and distributed throughout the area. Photograph of Dalecarlia Plant by EPA Photo.

EDCs also enter the Potomac watershed from antibiotics and
synthetic hormones given to cattle and poultry to prevent disease and
stimulate growth. Once excreted by the animals, the chemicals find their
way to the river, usually via rain runoff. In Shenandoah and Potomac
tributaries upriver, cattle are allowed to walk into the water, a form of
“direct deposit,” Blazer says.

“We don’t have smoking guns that tell us what specific
chemicals may be causing problems in the river,” says Potomac
Riverkeeper’s Ed Merrifield, “and it could take years to find out what
chemical or chemicals cause intersex fish.”

Even if we could identify potentially dangerous EDCs, current
municipal water-filtration methods in our area cannot remove them, nor
does the EPA require them to. A recent USGS study of several rivers
nationwide, including the Potomac, reported the same concentrations of
some compounds in the river water before and after it went through the
filtration process.

Many of the EDCs that flow into the Potomac River and other
bodies of water are thought to be estrogenic, meaning they mimic estrogen
hormones in the body.

“Estrogenic compounds are important, but they are just part of
the picture,” says the USGS’s Luke Iwanowicz. “We have also found
androgenic compounds in the river that we suspect come from livestock
feeding, and we’d like to find out what else is in the river. A lot of
people throw away anti-inflammatory medications, and I also want to see if
there are thyroid hormones in the river. I’d be shocked if there

“The exposure to EDCs that we get just from drinking water is
probably a very low level,” Blazer says, “but we know EDCs get past the
placental barrier and enter the embryo, when the organism is most
sensitive, and this is when we really need to worry because very low
levels at those times will have a harmful impact. The changes initiated by
EDCs may not show up until the person goes through sexual maturity or
later. There are all sorts of things we don’t understand right

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In time, the impact of EDCs on humans will be better
understood. The technology for measuring human exposure to synthetic
chemicals has advanced in recent years. Centers for Disease Control and
Prevention (CDC) labs now can monitor human blood and urine for more than
200 so-called halogenated and non-halogenated chemicals and their
metabolites. These include pesticides and chemicals used in cosmetics,
perfumes, detergents, toys, plastics, and fire retardants. But the ways in
which different EDCs might combine in the human body will likely remain
uncertain for some time.

The Washington Aqueduct, headquartered on MacArthur Boulevard
in Northwest DC, is the major supplier of drinking water for the District
and parts of Northern Virginia, including Arlington and Falls Church. The
aqueduct distributes some 160 million gallons of drinking water a day, and
on hot days up to 180 million gallons.

The Washington Suburban Sanitary Commission, in Maryland,
distributes water from the Potomac to homes and businesses in Montgomery
and Prince George’s counties and has two reservoirs on the Patuxent River
that distribute water to parts of Prince George’s.

Fairfax Water serves Fairfax County and Alexandria; 55 percent
of its water is drawn from the Potomac and the remaining 45 percent from
the Occoquan Reservoir. These are the area’s three major suppliers of tap

Tom Jacobus, general manager of the Washington Aqueduct, says
current water-filtering technology doesn’t neutralize EDCs that enter the
system from the river’s intake pipes, but he notes that those levels are
very low.

“The problem right now is we don’t know the effect of very low
levels of EDCs on human health,” Jacobus says. “So we are trying to decide
what kinds of water treatments we may need to go after some of these
endocrine-disrupting compounds. Right now I can say without qualification
that our drinking water meets all federal standards and therefore is safe
to drink. But that is not a good enough answer, because safe enough for
whom? So we are looking into the possibility of installing ozone UV [a
technology that has the capacity to remove many EDCs from water] to
further ensure that we can neutralize the anthropomorphic activity of EDCs
in the water, but there are significant costs to this and other new
technologies as well.”

The Blue Plains Advanced Wastewater Treatment Plant, in
Southwest DC, the world’s largest such plant, treats and discharges 370
million gallons of Washington-area wastewater a day—up to a billion
gallons during rainstorms. Untreated water is piped in from the District,
suburban Maryland, and Fairfax and Loudoun counties and is pumped back
into the Potomac River after it undergoes tertiary treatment. Says George
Hawkins, general manager of the District of Columbia Water and Sewer
Authority: “We put back water into the Potomac that is often cleaner than
the water in the Potomac. It is a remarkable technical

But just as the Washington Aqueduct doesn’t filter out EDCs,
neither does Blue Plains or upriver wastewater-treatment plants in
Rockville and Poolsville, whose treated wastewater goes into the Potomac
and finds its way to the Washington area’s water-intake pipes, to be
recirculated through our freshwater supply.

Hawkins, former director of DC’s Department of the Environment,
says the water industry is paying a lot of attention to EDCs. A local
group formed to investigate the issue decided that not enough science is
currently available about EDCs to justify the expense of trying to remove

“We need to know which of these new contaminants may pose the
greatest health dangers so we can develop a plan,” Hawkins says, “because
right now our ability to detect these chemicals as low as one part per
trillion has outstripped our ability to know what their consequences may
be. But does this issue of endocrine disrupters keep us awake at night?
You’re doggone right it does.”

In the best of all worlds, the Clean Water Act of 1972 might
have eliminated the EDC problem in the water supply before it began, or at
least reduced it, because a goal of the act was to prevent all manmade
pollution from entering our waterways. While that law has led to
improvements in the quality of many of our nation’s waterways, it is also
routinely ignored. According to EPA data reported in the New York
in September 2009, between 2004 and 2009 there were 506,000
violations of the Clean Water Act nationwide.

At DC’s southern tip, the Blue Plains Advanced Wastewater Treatment Plant—the world’s largest of its type—treats about 300 million gallons of wastewater a day and returns it to the Potomac. Photograph of blue plains plant by Chesapeake Bay Program.

In 1996, Congress created an EPA office dedicated to EDC
research, called the Endocrine Disruptor Research Initiative. It has yet
to release significant information about the risk of EDCs to metropolitan
drinking water.

Now that we know our drinking water contains EDCs, here is the
question: Even at the very low concentrations that EDCs reach Washington’s
water-intake pipes, is there evidence that they pose human health
consequences? If so, what are they?

Two of the most remarkable aspects of the current obesity
epidemic are its scope and the rapidity with which it has grown. Between
1980 and 2008, obesity rates have doubled worldwide, according to a study
published in the British medical journal the Lancet, and other
studies have shown a threefold increase in North America and Europe. The
epidemic cuts across socioeconomic, age, and sex lines.

In 2000, no state in the US had an adult obesity rate higher
than 30 percent, according to the CDC. By 2010, 12 states had reached that
level, and another eight states are close. It’s estimated that more than a
third of adult Americans are clinically obese and that 68 percent of
Americans age 20 and older are overweight or obese.

Obesity is considered a threat to human health by the National
Institutes of Health and the World Health Organization. WHO says more
people in the world now are obese than are undernourished. A risk factor
for Type II diabetes, cardiovascular disease, stroke, and high blood
pressure as well as for breast, colon, and renal cancers, obesity is a
major force driving up health-care costs.

Why have we gotten so fat so fast? In children, the rapid rise
of obesity and Type II diabetes has been linked to everything from too
much TV and video games to fast food and the lack of physical education in
schools. A recent WHO statement lays the blame on less exercise coupled
with increased consumption of “nutrient-poor foods” with high levels of
sugars and saturated fats.

All of these factors probably are contributing to the rise in
obesity, but until recently no one linked the epidemic to the disruption
of hormonal regulation, which can change our bodies and diminish our
ability to stabilize weight.

A 2009 statement issued by the Endocrine Society, called
“Endocrine-Disrupting Chemicals,” found “alarming signals” that EDCs may
be triggering obesity and other serious health problems. In many if not
most cases, research indicates that prenatal and early childhood are the
most vulnerable periods because exposure can affect development. Health
problems may not be seen until many years later; this situation has given
rise to an area of scientific inquiry called “the developmental origins of
adult disease.”

The report noted that the increasing incidence of obesity
matches the rise in industrial chemicals in the environment, and it cites
a number of scientific studies linking certain EDCs (called obesogens) to

The first-of-its-kind statement went through “incredible
scrutiny,” says Dr. Andrea C. Gore, one of the coauthors. It’s 54 pages
long and lists 485 scientific papers to support its claims that EDCs
appear to be triggering obesity and other human-health problems, including
diabetes and cardiovascular disease.

Says Gore, a professor of pharmacology and toxicology at the
University of Texas: “We felt there is a very strong weight of evidence
supporting the link between endocrine disrupters and dysfunctions in all
the endocrine systems in humans and wildlife. Much of that is based on
very good lab research that has been coming out in recent years. So the
reason we were able to make such a strong statement is that the data
really support it.”

The report says: “The literature demonstrates a role of EDCs in
the etiology of complex diseases such as obesity, diabetes mellitus, and
cardiovascular disease, yet these processes are still poorly

The report goes on to explain that “even infinitesimally low
levels of exposure—indeed, any exposure at all—may cause endocrine or
reproductive abnormalities, particularly if exposure occurs during a
critical developmental window.” Surprisingly, the report found that “low
doses may even exert more potent effects than higher doses.”

Because EDCs are ubiquitous in the environment, it’s unclear
whether those we get from drinking water play a prominent role in human
health, but a reasonable assumption based on the fish kills and other
evidence is that they could.

EDCs have also been linked to the rising rates of breast and
prostate cancers, both of which are hormone-related. There are undoubtedly
many environmental and genetic factors involved in cancers, but one of the
strongest pieces of evidence for the role of EDCs in prostate cancer came
out of a large epidemiological study conducted by the National Cancer
Institute and the National Institute of Environmental Health Sciences. The
study evaluated more than 55,000 agricultural pesticide applicators in
North Carolina and Iowa and found that exposure to pesticides, some of
which may interrupt normal hormonal balance, increased prostate-cancer
rates in men with a family history of the disease, leading the authors to
speculate that the pesticides interacted with genes in those

According to the Endocrine Society paper, several signals
suggest that people may be at risk for reproductive compromise because of
EDCs. Declining male sperm counts reported in countries around the world,
including the United States, may be linked to EDC exposure, the report
says. Additionally, young women in the 15-to-24-year-old group currently
have the fastest-growing rate of involuntary subfertility. Subfertility
doesn’t mean that a woman can’t bear children but that she may encounter
more difficulty and delay in becoming pregnant than would otherwise be

There are some indications that hypospadias, a malformation of
the urethra, may develop in a baby boy when a genetic susceptibility is
triggered by environmental exposure prior to pregnancy or within the first
16 weeks of fetal development, the time when the urethra develops.
Epidemiologic studies suggest that environmental exposures increase the
incidence of hypospadias and other birth defects.

According to the CDC, metabolites from one type of phthalate
were found to be five times higher in the urine of American women ages 20
to 40 than in any other segment of the population. Phthalates make
plastics flexible and are used in perfumes, nail polish, and shampoos. The
phthalate from the study, dibutyl phthalate, has been found to be
estrogenic in laboratory animals, leading to developmental disorders in
male offspring. It also interferes with the thyroid system.

A study in the United Kingdom found that the male children of
vegetarian mothers, who consumed more phytoestrogens from agricultural
fertilizers than mothers on regular diets, had five times the rate of
hypospadias as the sons of nonvegetarian mothers.

Many theories have been advanced to account for the increasing
prevalence of autism in children, a disorder the Autism Society of America
calls “the fastest-growing development disability” in the world. A CDC
report in the June 2011 issue of Pediatrics reported that the
percentage of children and teens in the US diagnosed with developmental
disabilities such as autism has increased by 17 percent since the late
1990s. This upward trend of neurological impairment was also seen in the
increased prevalence of attention deficit hyperactivity disorder as well
as stuttering and learning disabilities.

While genes probably play a role, there is growing suspicion
that EDCs are also involved in a range of neurological impairments,
including autism.

Gore notes that autism is a complicated disorder and has no
single cause. But, as with obesity and hormone-related cancers, she says,
“the timing of autism’s increase in the population also coincides with the
rise of EDCs in the environment. We don’t want to overinterpret the data,
but the ways in which we’ve changed the environment appear to be changing
how our brains develop. Low-dose exposures in early development are very
important and very potent, but the problem is it is hard to detect

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For example, a large body of evidence from the Great Lakes and
other areas links maternal polychloride byphenyl (PCB) exposure, largely
from fish consumption by mothers during pregnancy, to lower IQs in
children. One avenue by which PCBs are believed to do this damage is
through thyroid disruption. Normal thyroid function is vital to proper
neurological development.

“A loss of four or five IQ points may not seem like such a big
deal,” Gore says, “but when you consider the whole shift of the
population’s IQ because people are being exposed to these contaminants,
there could potentially be a dumbing-down of the population.”

Once used widely by industry for many purposes, including as a
lubricant and coolant, PCBs were banned in 1979 because of environmental
concerns. Made by combining benzene and chlorine, PCBs—which are
classified as endocrine disrupters—sink to the bottoms of rivers and
lakes. They enter aquatic plants and, when fish eat them, become part of
the human food chain. When people consume them, they get stored in

PCBs also aerosolize—meaning they break down over time and can
turn into a fine, powdery substance carried by wind—and as a result are in
virtually every body of water in the world, including the Potomac River.
The EPA has issued a PCB advisory warning against the consumption of fish
from the Potomac, especially of bottom feeders such as carp and

Scientific studies show that salmon raised in fish farms in the
Atlantic Ocean have a heavier burden of PCBs than salmon caught in the
wild—in part because farm-raised salmon don’t swim as vigorously as those
in the wild and as a result have more body fat. Although there are fewer
PCBs in the environment than before, because of their long half-life they
continue to pose a danger to humans, especially during early

The best way to prevent EDCs from entering Washington’s
drinking water would be to keep them out of the Potomac River in the first
place. Tom Jacobus notes that the Potomac River Basin Drinking Water
Source Protection Partnership was formed by area water utilities in 2004
to address this issue. Although the body has no enforcement powers, it’s
working with the Environmental Protection Agency and agricultural
extension services in the states to raise awareness of the consequences of
such practices as allowing cattle, especially those treated with hormones,
to roam freely in tributaries. Efforts are also being made to convince
cattle and chicken operations to control runoff into the river. Jacobus
says the message is simple: “If you have a cattle-feeding operation that
uses a lot of hormones, please don’t let the cattle have access to the
water, and control your runoff.”

Jacobus says the best way to keep EDCs from the river is not to
put them there in the first place. “I would also ask people not to throw
your pills down the toilet and to look at labels on personal-care products
and avoid those that may have EDCs in them.” This is an important message
but one unlikely to be heeded by most people.

Because there are hundreds if not thousands of chemical
compounds, Jacobus says, water officials are trying to get a clearer
understanding of the classes of chemicals and to regulate them: “We are
looking at new and innovative treatment techniques, and within two years
we will have treatment plans for some EDCs. We need to determine as an
industry what these treatment levels should be, and we need to look at
cost-effectiveness. Some of these EDC-removal technologies could cost $100
million. Ozone treatment, for example, works through electricity, so it’s
expensive to operate. We’re not resisting this, but we don’t want to get
ahead of the science.”

For now, Jacobus says, the Washington Aqueduct will continue to
monitor the EDC issue. “We have a lot of confidence in the EPA, but at the
same time we want to do better than EPA regulations because our customers
want to us remove some of the unknown,” he says. “We are also involved in
a cooperative research project to understand more about
endocrine-disrupting compounds and their role in drinking

“From the science we know now, we do not see a threat to
drinking water at levels we can detect. But are we looking at it and
thinking of future treatments? Yes, we are.”

Contributing editor John Pekkanen has written about health and medicine for more than three decades. His September 2011 article, “Coming Back: Battling the Invisible Wounds of War,” about military servicemembers with brain injuries that would have been fatal in earlier times, can be found here.

This article appears in the July 2012 issue of The Washingtonian.