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A comprehensive
survey of the
drinking water for
more than 28 million
Americans has
detected the
widespread but
low-level presence
of pharmaceuticals
and hormonally
active chemicals.
Little was known
about people's
exposure to such
compounds from
drinking water, so
Shane Snyder and
colleagues at the
Southern Nevada
Water Authority
in Las Vegas
screened tap water
from 19 US water
utilities for 51
different compounds.
The surveys were
carried out between
2006 and 2007.
The 11 most
frequently detected
compounds - all
found at extremely
low concentrations -
were:
• Atenolol, a
beta-blocker used to
treat cardiovascular
disease
• Atrazine, an
organic herbicide
banned in the
European Union, but
still used in the
US, which has been
implicated in the
decline of fish
stocks and in
changes in animal
behaviour
•
Carbamazepine, a
mood-stabilising
drug used to treat
bipolar disorder,
amongst other things
• Estrone, an
oestrogen hormone
secreted by the
ovaries and blamed
for
causing
gender-bending
changes in fish
• Gemfibrozil,
an
anti-cholesterol
drug
• Meprobamate,
a
tranquiliser widely
used in psychiatric
treatment
• Naproxen, a
painkiller and
anti-inflammatory
linked to increases
in asthma incidence
• Phenytoin,
an anticonvulsant
that has been
used to treat
epilepsy
•
Sulfamethoxazole, an
antibiotic used
against the
Streptococcus
bacteria, which is
responsible for
tonsillitis and
other diseases
• TCEP, a
reducing agent used
in molecular biology
• Trimethoprim,
another antibiotic
The
concentrations of
pharmaceuticals in
drinking water were
millions of times
lower than in a
medical dose, and
Snyder emphasises
that they pose no
public health
threat. He cautions,
though, that "if a
person has a unique
health condition, or
is concerned about
particular
contaminants in
public water
systems, I strongly
recommend they
consult their
physician".
Christian Daughton
of the EPA's
National Exposure
Research Laboratory
says that neither
this nor other
recent water
assessments give
cause for health
concern. "But
several point to the
potential for risk -
especially for the
fetus and those with
severely compromised
health." Daughton
says the
contamination
surveys help people
realise how they are
intimately and
inseparably
connected with their
environment. "The
occurrence of
pharmaceuticals in
the environment also
serves to make us
acutely aware of the
chemical sea that
surrounds us," he
says.
Modern life
While
the US government
regulates the levels
of pathogens in US
drinking water,
there are no rules
for
pharmaceuticals and
other compounds,
apart from one: the
herbicide atrazine.
The atrazine levels
measured by Snyder
and colleagues were
well within federal
limits.
Snyder says water
utilities could make
drinking water
purer. But the costs
of "extreme
purification" - far
beyond what is
needed for safety
alone - are huge in
terms of increased
energy usage and
carbon footprint.
Ultra-pure water
might not even be
safe, adds Snyder.
The widespread
occurrence of
pharmaceuticals and
endocrine disruptors
reflects improved
detection
techniques, rather
than greater
pollution, says
Snyder.
Contamination is a
fact of modern life,
he adds.
"As we continue
to populate and
aggregate, our
wastes will
certainly accumulate
where we live," he
says. "We as a
species have decided
to live a modern
life, with
pharmaceuticals,
plastics,
transportation -
therefore we must
accept that there
will be a certain
degree of
contamination."
Journal
reference:
Environmental
Science and
Technology, in
press |
