Pharmaceuticals
In Our Water Supplies
Are
“Drugged Waters” a Water Quality Threat?
Arizona
Water Resource
Developed
to promote human health and well being, certain pharmaceuticals are
now attracting attention as a potentially new class of water pollutants.
Such drugs as antibiotics, anti-depressants, birth control pills,
seizure medication, cancer treatments, pain killers, tranquilizers
and cholesterol-lowering compounds have been detected in varied water
sources.
Where
do they come from? Pharmaceutical industries, hospitals and other
medical facilities are obvious sources, but households also contribute
a significant share. People often dispose of unused medicines by flushing
them down toilets, and human excreta can contain varied incompletely
metabolized medicines. These drugs can pass intact through conventional
sewage treatment facilities, into waterways, lakes and even aquifers.
Further, discarded pharmaceuticals often end up at dumps and land
fills, posing a threat to underlying groundwater.
Farm
animals also are a source of pharmaceuticals entering the environment,
through their ingestion of hormones, antibiotics and veterinary medicines.
(About 40 percent of U.S.-produced antibiotics are fed to livestock
as growth enhancers.) Manure containing traces of such pharmaceuticals
is spread on land and can then wash off into surface water and even
percolate into groundwater.
Along
with pharmaceuticals, personal care products also are showing up in
water. Generally these chemicals are the active ingredients or preservatives
in cosmetics, toiletries or fragrances. For example, nitro musks,
used as a fragrance in many cosmetics, detergents, toiletries and
other personal care products, have attracted concern because of their
persistence and possible adverse environmental impacts. Some countries
have taken action to ban nitro musks. Also, sun screen agents have
been detected in lakes and fish.
Researchers
Christian G. Daughton and Thomas A. Ternes reported in the December
issue of “Environmental Health Perspectives” that the amount
of pharmaceuticals and personal care products entering the environment
annually is about equal to the amount of pesticides used each year.
Concern
about the water quality impacts of these chemicals first gained prominence
in Europe, where for over a decade scientists have been checking lakes,
streams, and groundwater for pharmaceutical contamination. American
officials and scientists are taking note, with two recent U.S. professional
organizations — the National Ground Water Associations and the
American Chemical Society — addressing the issue at their annual
meetings this summer.
The
issue emerged in Europe about ten years ago, when German environmental
scientists found clofibric acid, a cholesterol-lowering drug, in groundwater
beneath a German water treatment plant. They later found clofibric
acid throughout local waters, and a further search found phenazone
and fenofibrate, drugs used to regulate concentrations of lipids in
the blood, and analgesics such as ibuprofen and diclofenac in groundwater
under a sewage plant. Meanwhile other European researchers discovered
chemotherapy drugs, antibiotics and hormones in drinking water sources.
In
the United States, the issue might have attracted earlier notice if
officials had followed up on observations made 20 years ago. At that
time, EPA scientists found that sludge from a U.S. sewage-treatment
plant contained excreted aspirin, caffeine and nicotine. At the time,
no significance was attached to the findings.
In
Phoenix about this time another event occurred that also might have
alerted officials that pharmaceuticals could pose a water quality
threat. Herman Bouwer of the U.S. Agricultural Research Service in
Phoenix recalls that clofibric acid was found in groundwater below
infiltration basins that were artificially recharging groundwater
with sewage effluent. Bouwer says more attention should have been
paid to the finding; if clofibric acid could pass through a sewage
treatment plant and percolate into the groundwater so also could many
other drugs.
Europeans,
however, took the lead in researching the issue. In the mid-1990s,
Thomas A. Ternes, a chemist in Wiesbaden, Germany, investigated what
happens to prescribed medicines after they are excreted. Ternes knew
that many such drugs are prescribed, and that little was known of
the environmental effects of these compounds after they are excreted.
He researched the presence of drugs in sewage, treated water and rivers,
and his findings surprised him.
Expecting
to identify a few medicinal compounds he instead found 30 of the 60
common pharmaceuticals that he surveyed. Drugs he identified included
lipid-lowering drugs, antibiotics, analgesics, antiseptics, beta-blocker
heart drugs, residues of drugs for controlling epilepsy as well as
drugs serving as contrast agents for diagnostic X rays.
Results
of recent research in North America also indicate reason for concern.
At the June National Groundwater Association conference, Glen R. Boyd,
a Tulane University civil engineer, reported detecting drugs in the
Mississippi River, Lake Ponchetrain and in Tulane’s tap water.
Boyd and his team found in tested waters low levels of clofibric acid,
the pain killer naproxen and the hormone estrone. Samples of Tulane’s
tap water showed estrone averaging 45 parts per trillion with a high
of 80 parts per trillion.
At
the recent American Chemical Society conference, Chris Metcalfe of
Trent University in Ontario reported finding a vast array of drugs
leaving Canadian sewage treatment plants, at times at higher levels
than what is reported in Germany. Such drugs included anticancer agents,
psychiatric drugs and anti-inflammatory compounds. North American
treatment plants may show higher levels of pharmaceuticals because
they often lack the technological sophistication of German facilities.
The
U.S.G.S. is currently conducting the first nationwide assessment of
“emerging contaminants” found in selected streams, including
the occurrence of human and veterinary pharmaceuticals, sex and steroidal
hormones and other drugs such as antidepressants and antacids. One
hundred stream sites were identified, representing a wide variety
of geographical and hydrogeological settings. Four of these sites
are in Arizona: Santa Cruz River at Cortaro Road; Santa Cruz River
near Rio Rico; Salt River below 91st Ave. sewage treatment plant;
and Gila River above diversions at Gillespie Dam.
| Mapping
of human genome means more drugs, possibly more pollution
Pharmaceuticals
are greatly increasing in numbers and kinds, with greater
likelihood of releases into the environment. Before the
recent announcement of the almost complete categorization
of the human genome, Christian G. Daughton and Thomas
A. Ternes wrote in an article that appeared in Environmental
Health Perspectives, “The enormous array of pharmaceuticals
will continue to diversify and grow as the human genome
is mapped. Today there are about 500 distinct biochemical
receptors at which drugs are targeted. ... The number
of targets is expected to increase 20-fold (yielding 3,000
to 10,000 drug targets) in the near future.” The
authors warn, “This explosion in new drugs will severely
exacerbate our limited knowledge of drugs in the environment
and possibly increase the exposure/effects risks to nontarget
organisms.” |
|
Stream
sites were chosen that were expected to be highly susceptible to contamination
by targeted compounds. Testing the sites will provide an initial indication
of the potential for these compounds to enter the environment, as
well provide an opportunity for developing suitable laboratory methods
for measuring compounds in environmental samples at very low (sub-ppb)
levels.
Detected
contaminants include caffeine, which was the highest-volume pollutant,
codeine, cholesterol-lowering agents, anti-depressants, and Premarin,
an estrogen replacement drug taken by about 9 million women. Also
chemotherapy agents were found downstream from hospitals treating
cancer patients. Final results from the study are expected to be released
in the fall. For additional information about the U.S.G.S. study check
the website: toxics.usgs.gov/regional/emc.html
What
risk does chronic exposure to trace concentrations of pharmaceuticals
pose to humans or wildlife? Some scientists believe pharmaceuticals
do not pose problems to humans since they occur at low concentrations
in water. Other scientists say long-term and synergistic effects of
pharmaceuticals and similar chemicals on humans are not known and
advise caution. They are concerned that many of these drugs have the
potential of interfering with hormone production. Chemicals with this
effect are called endocrine disrupters and are attracting the attention
of water quality experts.
To
some scientists the release of antibiotics into waterways is particularly
worrisome. They fear the release may result in disease-causing bacteria
to become immune to treatment and that drug-resistant diseases will
develop.
Scientists
generally agree that aquatic life is most at risk, its life cycle,
from birth to death, occurring within potentially drug-contaminated
waters. For example, anti-depressants have been blamed for altering
sperm levels and spawning patterns in marine life. Most studies of
pharmaceutical and pharmaceutically active chemicals in water have
mostly focused on aquatic animals.
For
example, recent British research suggest that estrogen, the female
sex hormone, is primarily responsible for deforming reproductive systems
of fish, noting that blood plasma from male trout living below sewage
treatment plants had the female egg protein vitellogenin. This finding
would seem to be consistent with what U.S. researchers suspect has
occurred downstream from treatment plants in Las Vegas and Minneapolis.
Carp in these areas show the same effects as the British fish.
Some
scientists believe arid regions of the West are especially vulnerable
to the effects of drug-contaminated effluent. These areas are more
likely to have streams that rely almost entirely on effluent for flow,
especially during dry months. Further, effluent is extensively used
in irrigation and even for recharging drinking water aquifers. Also,
areas of the West have attracted large number of retired people who
are likely to use more pharmaceuticals than other population segments;
thus more pharmaceuticals in wastewater.
Drugged
Drinking Water
We should no longer think of water as a gift of nature but an industry
which needs investment.
Environmental
Health Perspectives Volume 108, Number 10, October 2000
Drugs
and personal care products that are excreted from or washed off the
body naturally end up in the sewage that flows into sewer systems
and septic tanks, but where do they go from there? Scientists are
beginning to monitor the extent of pharmaceutical and personal care
products (PPCPs) in the aquatic environment and their consequences.
What they're finding is that, through leaching from septic tanks and
escaping intact through sewage treatment processes, some of these
substances are ending up back in the drinking water.
Germany
has been at the forefront of PPCP monitoring. Studies conducted there
during the past 10 years confirmed the presence of PPCPs in treated
and untreated sewage effluent, surface water, groundwater, and drinking
water. Most commonly found were anti-inflammatory and pain-killing
drugs, cholesterol-lowering drugs, anticonvulsants, and sex hormones
from oral contraceptives. Samples from 40 German rivers and streams
turned up residues of 31 different PPCPs, according to a report presented
at the March 2000 American Chemical Society meeting in San Francisco,
California, by Thomas Ternes, a chemist at the Institute for Water
Research and Water Technology in Wiesbaden.
Researchers
worldwide have discovered more than 60 different PPCPs in water sources,
according to Christian Daughton, chief of the Environmental Chemistry
Branch of the U.S. Environmental Protection Agency (EPA) Environmental
Sciences Division in Las Vegas, Nevada. In addition to the drugs noted
above, the list includes antineoplastics, beta-blockers, bronchodilators,
lipid regulators, hypnotics, antibiotics, antiseptics, X-ray contrast
agents, sunscreen agents, caffeine, and fragrances such as synthetic
musks. Most PPCPs are detected at concentrations ranging from parts
per trillion to parts per billion, and originate in treated and untreated
sewage, says Daughton, who coauthored an article on PPCPs in the December
1999 issue of EHP Supplements.
North
American researchers are just beginning to look at the issue of PPCPs.
Studies presented at the June 2000 Emerging Issues Conference sponsored
by the National Ground Water Association, held in Minneapolis, Minnesota,
indicate that the problem exists here, too. For example, environmental
scientist Chris Metcalfe of Trent University in Peterborough, Ontario,
detected the drugs aspirin, ibuprofen, indomethacin, bezafibrate (a
cholesterol regulator), and carbamazepine (an anticonvulsant) in 10
pre- and post-treatment samples from sewage treatment plants in eastern
Canada. The sewage treatment process in place removed some drugs that
were easily biodegradable or more amenable to removal by activated
charcoal, degradative microbes, or sand filtration, but others were
resistant to degradation.
Metcalfe
is just beginning to analyze the effects of cholesterol-lowering drugs,
estrogens, and anticonvulsants on fish in the Great Lakes. All three
drug types can potentially interfere with normal reproduction and
development in fish living downstream from sewage treatment plants.
His laboratory studies show that estrogen compounds at parts-per-trillion
exposures feminize male fish and disrupt the development of the circulatory
system, eyes, and bladder. He says it's too soon to know whether PPCPs
adversely affect wild fish populations.
In
one of the first studies in the United States to report the occurrence
of drugs in drinking water, environmental engineer Glen Boyd had his
students at Tulane University in New Orleans, Louisiana, sample water
from the Mississippi River, a local lake, and city tap water. Their
preliminary experiment targeted the pain reliever naproxen, the sex
hormone estrone, and clofibric acid, a major bioactive metabolite
from certain anticholesterol drugs. All three were detected at varying
concentrations in most of the samples. "The big unknown,"
says Boyd, "[is whether PPCPs] present a health concern now or
in the future." He notes that, although the number of peer-reviewed
papers on the topic is limited, government agencies concerned with
water quality in the United States and professional organizations
serving the water and wastewater communities are beginning to acknowledge
PPCPs as an emerging environmental issue.
The
long-term outcome of humans ingesting subtherapeutic doses of numerous
drugs as well as any dose at all of substances not meant to be ingested
remains a major unaddressed issue. "In areas of water scarcity,
we'll see more and more reuse of treated sewage to meet drinking water
needs," predicts Daughton, thereby increasing the likelihood
that PPCPs will end up in drinking water. Extensive monitoring of
the occurrence of PPCPs and their concentration trends over time is
required to ensure safe water supplies in the future. Then toxicologists
need to determine if the kinds and amounts of PPCPs that occur affect
people and other living creatures. This subject will require collaboration
between the Food and Drug Administration and the EPA, says Daughton,
since the former usually does not address environmental concerns and
the latter generally does not deal with drug issues.
-Carol Potera
Pharmaceuticals
And Endocrine Disruptors In Rivers And On Tap
Robert
W. Masters
National Ground Water Association
(NGWA)
Pharmaceuticals showing up in rivers downstream from sewage plants
have raised concerns now that several public water systems have tested
positive for drugs. Tap water in Wheeling, West Virginia, and the
Ohio River tested positive for antibiotics according to USA Today
November 7, 2000. A 17-year old high school student named Ashley Mulroy
won the Stockholm Junior Water Prize for her project which found three
common antibiotics (penicillin, tetracycline, and vancomycin) in the
river and more alarming, on tap. She is not the first researcher to
find drugs on tap. Thomas Heberer of the University of Berlin, Germany,
presented his findings ofvarious drugs in tap water in last year's
National Ground Water Association (NGWA) international conference
on emerging issues. The NGWA conference held in Minneapolis, June
7-8, 2000, was covered on Minnesota Public Radio on “Morning
Edition” June 8. Keynote Speaker Janet Raloff, author of “Drugged
Waters,” and Dana Kolpin of the U.S. Geological Survey were
interviewed. Pharmaceuticals and endocrine disrupting chemicals in
water sparked international interest as scientists from the United
States (U.S.), Canada, England, and Germany attended the ground-breaking
conference at the Hyatt Regency, Minneapolis. Largescale investigations
are underway in over 100 of America's rivers and streams. Current
drinking water standards do not require testing for any of the over
7,000 pharmaceutical compounds being prescribed, so why bother?
DRUG
RESISTANT BACTERIA
One of the dominating concerns is the creation of “Superbugs.”
New strains of bacteria which are resistant to antibiotics are common
near major cities and in rural areas and have been found in all 15
rivers from one study, including the Mississippi, the Ohio, and the
Colorado. As bacteria is exposed to antibiotics they begin to adapt
in order to survive, not unlike some of the drug resistant staph infections
which have developed in hospitals. This is a concern, but like so
many of today's environmental issues, more research is needed.
HOGS DON'T DRINK COFFEE
In a society alarmed over large-scale animal feedlots termed Confined
Animal Feeding Operations (CAFO), Mad Cow, and hoof-and-mouth diseases,
the animal drugs have also entered the picture. Differentiating between
animal and man-made contamination becomes a challenge. Human pharmaceuticals
and caffeine have been used as tracers of man-made nitrate contamination
(Seiler et al., 1999). If you are deciding whether a large hog lot
or subdivision on septic systems caused elevated nitrate level in
water wells, you might consider testing for caffeine – hogs
don't drink coffee. In Seiler's research caffeine and prescription
drugs were used as evidence that household septic tank effluent was
communicating with the well.
ENDOCRINE
DISRUPTING CHEMICALS (EDC) AND WILDLIFE
EDC are compounds that interfere with natural production, release,
transport, metabolis m, binding, action, or elimination of hormones
in the body (Ankley et al., 1998). We know that the normal functions
of all organ systems are regulated by endocrine factors. Small disturbances
in endocrine function, especially during certain stages of the life
cycle, can lead to profound and lasting effects. There is evidence
that specific populations of invertebrate, fish, avian, reptilian,
and mammalian species have been, or currently are being, adversely
affected by exposure to environmental contaminants that effect the
endocrine systems. For example, there has been feminization of fish
from waterbodies receiving discharges of municipal and some types
of industrial effluents; there has been delayed or
abnormal sexual differentiation in alligators exposed to organochlorine
pesticides in lakes in Central Florida; and imposex (simultaneous
presence of both male and female reproductive organs) in different
species of marine gastropods has been strongly correlated with exposure
to tributyltin. The major groups of animals potentially at risk include
fish, birds, reptiles, marine mammals, and invertebrates (Ankley et
al., 1998).
MALE
FISH BECAME FEMALE
As early as 1963, a scientist by the name of Yamamoto and his colleagues
did numerous studies on the Japanese medaka, a freshwater fish native
to southeastern Asia, in which sexual differentiation was reversed
after administration of natural and synthetic hormones (Metcalfe et
al., 1999b). That’s right – newborn male fish became female. While
this work was done in the lab, the literature is quite clear that
human sewage is altering the sex steroids in fish. Shane Snyder, a
Ph.D. candidate at Michigan State, has tracked human estrogen Estradiol-17b
from sewage in the Las Vegas Wash to vitellogenin induction in male
fish. This protein, vitellogenin, is normally produced by reproducing
females. According to Snyder, estradiol in water in the parts per
trillion range can cause male fish to produce the egg making protein
vitellogenin (Raloff, 1998). Vitellogenin is a recognized biomarker
for exposure to estrogenic compounds. As analytical instruments become
more and more precise, it is now possible to detect compounds at concentrations
so minute that they were once considered insignificant. The Food and
Drug Administration (FDA) requires that drug manufacturers must demonstrate
that new medications have less than a part per billion concentration
in the environment before they are approved or face much more stringent
toxicity and risk testing (Masters, 2001).
IDENTIFYING
EDC
EDC are high on the U.S. Environmental Protection Agency (EPA) radar
screen. They can be natural hormones, pharmaceuticals such as birth
control pills, estrogen replacement products and other steroids, and
hundreds of organochlorine compounds found in pesticides and industrial
chemicals like PCBs and DDT. EDC appears to be persistent in the environment
and bioaccumulate, and exposures are widespread thoughout the entire
globe. Examples are organochlorines, cadmium, tributyltin, alkylphenols,
and estrogen. Compounds in the complex mixtures from pulp and paper
mills and municipal effluents have been shown to be EDC. Actually,
paper mill effluent has recently been determined to produce the male
hormone Androstenedione and masculinized fish. The paper mill sludge
contained the male steroid identical to the one made famous by baseball
slugger Mark McGuire (Raloff, 2001). Based on recognition of the potential
scope of the problem, the possibility of serious effects on the health
of populations and the persistence of some EDC in the environment,
research on EDC was identified as one of the six high-priority topics
in the EPA Office of Research and Development Strategic Plan, U.S.
EPA, 1996. U.S. EPA has developed a comprehensive plan to research
endocrine disruptors (Ankley et al., 1998).
HUMAN HEALTH
The question becomes - is there a risk to human health or is there
a disconnect between sound science and public perception? If you have
ever heard a drug commercial on TV with a long list of side effects
and “ask your doctor if it’s right for you,” it does make you wonder.
Currently there are insufficient data to resolve the question of human
health risk associated with pharmaceuticals in water. In general,
it is thought that modest amounts of chemical exposure seldom compromise
normal physiological functions. We know little about the concentrations
of EDC that would induce effects in various populations. Some of the
questions that must be addressed in the future are:
