[Pharmwaste] Article on pharmaceuticals and drinking water

[Janet Brown]

Technology News =E2=80=93August 4, 2005

Removing pharmaceuticals, hormones, and cosmetics from tap water

Forget well-known toxics such as pesticides and industrial chemicals: Scien=
tists are now focusing their energies on common household chemicals and med=
icines that are not regulated by the U.S. EPA but still come trickling out =
of your kitchen tap. Americans consume thousands of pharmaceuticals and pro=
duce tons of chemicals to maintain their modern lifestyles, and new finding=
s published today on ES&T=E2=80=99s Research ASAP website (es0484799) revea=
l that technologies to remove these products from drinking water have diffe=
rent levels of effectiveness.

=20
Shane Snyder
These large generators are located at the River Mountains Water Treatment F=
acility in Las Vegas, Nev. Ozone disappears within seconds after disinfecti=
ng water.=E2=80=9CI think the general overall pattern we are seeing is that=
 ozone is better at removal of these compounds,=E2=80=9D says Shane Snyder,=
 a project manager with the Southern Nevada Water Authority and one of the =
authors of the study. The research evaluated several water treatments commo=
nly used in the U.S., including chlorination, ozonation, and ultraviolet (U=
V) treatment.

When researchers compared the effectiveness of ozone and chlorine in removi=
ng 31 chemicals from drinking water, they found that ozone successfully eli=
minated far more chemicals at much higher percentages. Of the 31, 26 were r=
educed to at least 30% of their original concentration by ozonation. These =
substances included testosterone, estrogen, naproxen, caffeine, and the mos=
quito repellent DEET. Only two chemicals seemed resistant to ozonation: the=
 fragrance compound musk ketone and the flame retardant tri(2-chloroethyl) =
phosphate (TCEP).

For chlorine, 15 of the chemicals remained at levels exceeding 70% of their=
 original concentration. Like ozone, chlorine was ineffective at eliminatin=
g significant amounts of TCEP, but caffeine, progesterone, and the anticonv=
ulsant drug carbamazine also resisted degradation. Snyder adds, =E2=80=9CI =
don=E2=80=99t think it=E2=80=99s been recorded before, but chlorine was not=
 effective at removing testosterone.=E2=80=9D

Changes driven by cryptosporidium
The U.S. EPA began adding a series of new drinking-water rules=E2=80=94know=
n collectively as the Surface Water Treatment Rules=E2=80=94after the 1993 =
outbreak of cryptosporidium in Milwaukee, Wis. According to the Centers for=
 Disease Control and Prevention, more than 403,000 residents were sickened,=
 and the outbreak caused by this protozoan cost Milwaukee $96.2 million. Fr=
om 1990 to 2000, the U.S. faced nine other outbreaks of cryptosporidium ill=
nesses from contaminated water.

Cryptosporidium is a hardy protozoan that contaminates the water supply thr=
ough fecal contamination by humans, livestock, or wildlife. Ingestion of th=
e parasite causes diarrhea and may lead to death, especially in immunocompr=
omised people, such as HIV patients.

In 1994, 32 people died in Las Vegas, Nev., from cryptosporidium. =E2=80=9C=
It was never conclusively linked to the drinking water,=E2=80=9D says Snyde=
r, =E2=80=9Cbut the public relations problems caused us to move to ozone.=
=E2=80=9D He says that the destruction of hormones, personal care products,=
 and other chemicals in the process is an added benefit. =E2=80=94PDT
=E2=80=9COzone has been around to help with taste and odor for some time,=
=E2=80=9D says Craig Adams, a professor of environmental engineering at the=
 University of Missouri=E2=80=93Rolla. =E2=80=9COzone is also used for colo=
r removal if you have colored water. It=E2=80=99s really a holistic sort of=
 treatment, and it works better for some of these chemicals such as endocri=
ne disrupters.=E2=80=9D

Snyder has also compared ozone with UV treatment and found that the latter =
shows little effectiveness at destroying these chemicals. =E2=80=9CAt the d=
ose used in most plants for disinfection, there is essentially no removal o=
f these types of compounds,=E2=80=9D says Snyder. =E2=80=9CThat=E2=80=99s a=
 real disappointment because UV is actually a more modern type of disinfect=
ant.=E2=80=9D

But ozonation does have some drawbacks. Snyder points out that, like chlori=
nation, ozone generates byproducts that can be harmful. For instance, ozone=
 can generate bromate in water with high bromide levels. UV technology does=
 not create these problems because most organics are not very photoreactive=
.

Alan Roberson, the director of regulatory affairs with the American Water W=
orks Association, says that many cities designing new drinking-water facili=
ties are gravitating toward either UV or ozone because of EPA regulations a=
imed at controlling cryptosporidium. =E2=80=9CGenerally, you=E2=80=99re see=
ing the middle to large cities moving in this direction because they have t=
he financial resources and the skilled operators to run these plants,=E2=80=
=9D he says. He estimates that a switch to UV or ozone treatment might add =
about 10% to typical water treatment costs.

Snyder agrees that the switch to UV and ozone has been spurred by EPA=E2=80=
=99s Surface Water Treatment Rule, a response to outbreaks of cryptosporidi=
um that hit the U.S. in the 1990s (see sidebar). Chlorination is not very e=
ffective at removing the protozoan, but ozone works by directly attacking t=
he pathogenic cells, whereas UV scrambles the DNA inside.

Adams says that research into which treatment proves more effective at dest=
roying organic chemicals in the water is simply an added benefit for modern=
 water treatment. Researchers are finding these contaminants at levels so l=
ow that they might not even be harmful. =E2=80=9CThe precautionary principl=
e would say that if you can remove these substances in a reasonable manner,=
 then that is probably a good thing.=E2=80=9D =E2=80=94PAUL D. THACKER