Are Drugs And Chemicals
In Your Drinking Water ?
Residues of birth control pills, antidepressants, painkillers,
shampoos and a host of other compounds are finding their way into
waterways, and they have public health and environmental officials
in a regulatory quandary.
On the one hand, there is no evidence the traces of the chemicals
found so far are harmful to human beings. On the other hand, it
would seem cavalier to ignore them.
The pharmaceutical and personal care products, or P.P.C.P.'s,
are being flushed into rivers from sewage treatment plants or
leaching into groundwater from septic systems. According to the
Environmental Protection Agency, researchers have found these
substances, called "emerging contaminants," almost everywhere
they have looked for them.
Most experts say their discovery reflects better sensing technology
as much as anything else. Still, as Hal Zenick of the agency's
office of research and development put it in an e-mail message,
"there is uncertainty as to the risk to humans."
In part, that is because the extent and consequences of human
exposure to these compounds, especially in combination, are "unknown,"
the Food and Drug Administration said in a review issued in 2005.
And aging and increasingly medicated westerners are using more
of these products than ever.
So officials who deal with these compounds have the complex
task of balancing reassurance that they take the situation seriously
with reassurance that there is probably nothing to worry about.
As a result, scientists in several government and private agencies
are devising new ways to measure and analyze the compounds, determine
their prevalence in the environment, figure out where they come
from, how they move, where they end up and if they have any effects.
In many cases, the compounds enter the water when people excrete
them or wash them away in the shower. But some are flushed or
washed down the drain when people discard outdated or unused drugs.
So a number of states and localities around the country have started
discouraging pharmacies, hospitals, nursing homes and residents
from disposing of drugs this way. Some are setting up "pharmaceutical
take-back locations" in drugstores or even police stations. Others
are adding pharmaceuticals to the list of hazardous household
waste, like leftover paint or insecticides, periodically collected
for safe disposal, often by incineration.
In guidelines issued in February, three federal agencies, including
the E.P.A., advised people with leftover medicines to flush them
down the drain "only if the accompanying patient information specifically
instructs it is safe to do so." Otherwise, the guidelines say,
they should dispose of them in the trash (mixed with "an undesirable
substance" like kitty litter to discourage drug-seeking Dumpster
divers) or by taking them to designated take-back locations.
Worries about water-borne chemicals flared last summer when
researchers at the United States Geological Survey said they had
discovered "intersex fish" in the Potomac River and its tributaries.
The fish, smallmouth and largemouth bass, were male but nevertheless
carried immature eggs.
Scientists who worked on the project said they did not know
what was causing the situation, or even if it was a new phenomenon.
But the discovery renewed fears that hormone residues or chemicals
that mimic them might be affecting creatures that live in the
In a survey begun in 1999, the agency surveyed 139 streams around
the country and found that 80 percent of samples contained residues
of drugs like painkillers, hormones, blood pressure medicines
or antibiotics. The agency said the findings suggested that the
compounds were more prevalent and more persistent than had been
Meanwhile, the Food and Drug Administration started looking
into the effects of residues of antibiotics and antiseptics in
water, not just to see if they might affect people but also to
assess their potential to encourage the development of drug-resistant
Reports of contamination with pharmaceutical residues can be
alarming, even when there is no evidence that anyone has been
harmed. In 2004, for example, the British government reported
that eight commonly used drugs had been detected in rivers receiving
effluent from sewage treatment plants. A spokeswoman for the Department
for Environment, Food and Rural Affairs said it was "extremely
unlikely" that the residues threatened people, because they were
present in very low concentrations. Nevertheless, news reports
portrayed a nation of inadvertent drug users - "a case of hidden
mass medication of the unsuspecting public," as one member of
Parliament was quoted as saying.
Christopher Daughton, a scientist at the Environmental Protection
Agency and one of the first scientists to draw attention to the
issue, said P.P.C.P. concentrations in municipal water supplies
were even lower than they were in water generally because treatments
like chlorination and filtration with activated charcoal alter
or remove many chemicals. Dr. Daughton, who works at the agency's
National Exposure Research Laboratory in Las Vegas, said he believed
that if any living being suffered ill effects from these compounds,
it would be fish and other creatures that live in rivers and streams.
Dr. Daughton and Thomas A. Ternes of the ESWE-Institute for
Water Research and Water Technology in Germany brought the issue
to scientific prominence in 1999, in a paper in the journal Environmental
Health Perspectives. They noted that pollution research efforts
had focused almost exclusively on "conventional" pollutants -
substances that were known or suspected to be carcinogenic or
immediately toxic. They urged researchers to pay more attention
to pharmaceuticals and ingredients in personal care products -
not only prescription drugs and biologics, but also diagnostic
agents, fragrances, sunscreen compounds and many other substances.
They theorized that chronic exposure to low levels of these
compounds could produce effects in water-dwelling creatures that
would accumulate so slowly that they would be "undetectable or
unnoticed" until it was too late to reverse them. The effects
might be so insidious, they wrote, that they would be attributed
to some slow-moving force like evolution or ecological change.
Initial efforts concentrate on measuring what is getting into
the nation's surface and groundwater. The discharge of pharmaceutical
residues from manufacturing plants is well documented and controlled,
according to the E.P.A., but the contribution from individuals
in sewage or septic systems "has been largely overlooked."
And unlike pesticides, which are intentionally released in measured
applications, or industrial discharges in air and water, whose
effects have also been studied in relative detail, the environmental
agency says, pharmaceutical residues pass unmeasured through wastewater
treatment facilities that have not been designed to deal with
Many of the compounds in question break down quickly in the
environment. In theory, that would lessen their potential to make
trouble, were it not for the fact that many are in such wide use
that they are constantly replenished in the water.
And researchers suspect that the volume of P.P.C.P.'s excreted
into the nation's surface water and groundwater is increasing.
For one thing, per capita drug use is on the rise, not only with
the introduction of new drugs but also with the use of existing
drugs for new purposes and among new or expanding groups of patients,
like children and aging baby boomers.
Also, more localities are introducing treated sewage into drinking
water supplies. Researchers who have studied the issue say there
is no sign that pharmaceutical residues accumulate as water is
recycled. On the other hand, the F.D.A. said in its review, many
contaminants "survive wastewater treatment and biodegradation,
and can be detected at low levels in the environment."
Some say the spread of these substances in the environment is
an example of how the products of science and technology can have
unintended and unpredictable effects. In their view, when the
knowledge about these effects is sketchy, it is best to act to
reduce risk, even if the extent of the risk is unknown, an approach
known as the precautionary principle.
Joel A. Tickner, an environmental scientist at the University
of Massachusetts, Lowell, says that it is a mistake to consider
all of these compounds safe "by default," and that more must be
done to assess their cumulative effects, individually or in combination,
even at low doses.
In his view, our experience with lead additives, asbestos and
other substances shows it can be costly - in lives, health and
dollars - to defer action until evidence of harm is overwhelming.
Others say the benefits of action - banning some compounds,
say, or requiring widespread testing or treatment for others -
should at least equal and if possible outweigh their costs.
"You have to somehow estimate as well as possible what the likely
harms are and the likely benefits," said James K. Hammitt, a professor
of economics and decision sciences at the Harvard Center for Risk
And while it is possible that some of the tens of thousands
of chemicals that might find their way into water supplies are
more dangerous in combination than they are separately, Dr. Hammitt
said in an interview, "it's perfectly possible that they counteract
Anyway, he said, assessing their risk in combination is a mathematical
problem of impossible complexity. "The combinatorics of this are
Given all this uncertainty, policy makers find it difficult to
know what to do, other than continuing their research. Studies
of "the fate and transport and persistence" of the P.P.C.P.'s
will allow scientists to make better estimates of people's exposure
to them, Dr. Zenick said, and "to assess the potential for human
But even that normally anodyne approach comes under question
because of something scientists call "the nocebo effect" - real,
adverse physiological reactions people sometimes develop when
they learn they have been exposed to something - even if there
is no evidence it may be harmful.
"The nocebo effect could play a key role in the development
of adverse health consequences from exposure even to trace elements
of contaminants simply by the power of suggestion," Dr. Daughton
wrote recently in a paper in a special issue of Ground Water Monitoring
and Remediation, a publication of the National Ground Water Association,
an organization of scientists, engineers and businesses related
to the use of groundwater.
In fact, the idea that there are unwanted chemicals in the water
supply has many characteristics that researchers who study risk
perception say particularly provoke dread, regardless of their
real power to harm. The phenomenon is new (or newly known), and
the compounds are invisible and artificial rather than naturally
But scientists at agencies like the Geological Survey say it
is important to understand the prevalence and actions of these
compounds, even at low levels. If more is known about them, agency
scientists say, researchers will be better able to predict their
behavior, especially if they should start turning up at higher
concentrations. Also, the Geological Survey says, tracking them
at low levels is crucial to determining whether they have additive
effects when they occur together in the environment.
Comprehensive chemical analysis of water supplies "is costly,
extraordinarily time-consuming, and viewed by risk managers as
prompting yet additional onerous and largely unanswerable questions,"
Dr. Daughton wrote in his paper last year.
But it should be done anyway, he said, because it is a useful
way of maintaining public confidence in the water supply.
"My work is really categorized as anticipatory research," he
added. "You are trying to flesh out a new topic, develop it further
and see where it leads you. You don't really know where it leads."