red flag: bug repellent DEET turns up in Sun-Times tests of Chicago's drinking water

[Guest guest]

foto: Sun-Times reporter Zimmermann fills bottles with Chicago

tap water for testing.

( J. Kim/Sun-Times)

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'THIS RAISES A RED FLAG' | Potentially toxic bug repellent DEET turns

up in Sun-Times tests of Chicago's drinking water

April 21, 2008

BY STEPHANIE ZIMMERMANN

Staff Reporter szimmermann@...

http://www.suntimes.com/news/metro/905720,CST-NWS-water21.article

In this age of West Nile virus, Lyme disease and other insect-borne

health threats, millions of Americans have made slathering and spritzing

themselves with the powerful repellent DEET part of their summer

routine.

The insect repellent is used by 100 million Americans each year, in

total quantities exceeding the use of some agricultural pesticides.

But after we shower and wash our clothes, DEET winds up in rivers and

lakes.

And now, testing done for the Chicago Sun-Times has found, it's in our

drinking water.

The concentration detected in a sampling of Chicago tap water was low --

8.3 parts per trillion. Health experts said the level found in the

Sun-Times testing shouldn't pose a health hazard.

Still, said Mohamed Abou-Dania, a professor at Duke University who has

done extensive research on the neurological effects of DEET, " This

raises a red flag. [When] you have so many people using it, the risk is

there. "

And the chemical was detected in Chicago drinking water sampled in

March, when one would expect the use of mosquito repellent to be low.

The U.S. government doesn't have standards for DEET in drinking water.

Nor does it require the removal of other contaminants recently found in

other water studies -- including pharmaceuticals, flame retardants and

plasticizers.

Last month, Illinois officials announced that they are testing treated

and untreated water around the state for chemical compounds. The cities

whose water will be tested include Chicago, Elgin, Aurora, Rock Island

and East St. Louis. State officials said they expect to release results

of those tests in late June.

Chicago also is doing further sampling of raw Lake Michigan water and

finished drinking water, said Spatz, commissioner of the city's

Department of Water Management. Spatz said the city is using multiple

labs " to build a baseline database over time " and get a better idea of

what's in the water. He stressed that the trace amounts found so far

aren't hazardous but point to a need for better monitoring.

" The water is safe to drink, " said Spatz. " The last thing we want is to

erode confidence in the public water supply. "

Used as directed, DEET is considered safe for people over 2 months of

age. But at very high levels or when used long-term, DEET has been

implicated in nervous-system damage. Medical literature on the chemical

cites rare cases of children suffering poisoning or even death from

overexposure or ingestion of DEET.

Abou-Donia's studies of DEET exposure to laboratory rats found no effect

when a standard dose was used for 30 days. After 60 days, though,

brain-cell death occurred.

When DEET was approved a half century ago for consumer use, no one

considered the potential environmental effects.

But after DEET is washed down the drain, flushed down a toilet or thrown

in the garbage, it doesn't degrade quickly. It has been detected in

natural-water bodies throughout the United States, Europe, Australia and

even in the North Sea.

Chances are that it has been in our water for some time but we didn't

know it, said Stackelberg, a hydrologist with the U.S. Geological

Survey, because only recently has testing technology improved enough to

detect it.

Citing potential health and environmental concerns, some countries have

scaled back the amount of DEET allowed in consumer products. In Canada,

the maximum-allowed concentration is 30 percent. But in the United

States, consumers can readily buy repellents containing 100 percent

DEET.

Abou-Donia said concentrations above 30 percent are overkill and not

necessary, " especially if you have a child or infant. "

The drinking water in the Sun-Times tests came from an unfiltered

kitchen faucet in a home on the city's North Side -- sufficient to

indicate whether a wide range of chemicals might be present in the

city's drinking water, according to the Kelso, Wash., testing laboratory

Columbia Analytical Services.

The lab tested the water for the presence of 57 chemical compounds,

ranging from synthetic hormones and anti-convulsants to Prozac,

acetaminophen, methadone, flame retardants and plasticizers. Such

compounds are not required to be removed from drinking water, and

conventional treatment processes aren't equipped to catch them.

Though pharmaceuticals have been found in public water supplies

elsewhere, the only compound besides DEET that the Sun-Times sampling

detected was caffeine -- at what was described as a safe concentration

of 7 parts per trillion.

H. Grumbles, assistant administrator for water for the U.S.

Environmental Protection Agency, said in a statement that while " the

United States has one of the safest drinking-water supplies in the

world, " his agency " is concerned about the detection of a growing number

of pharmaceuticals and other personal-care products in water. These

contaminants occur at very low levels in water, and we continue to

evaluate their effects on public health and aquatic life. "

Unlike some chemical compounds, DEET remains fairly intact as it passes

through sewage or drinking-water treatment plants.

The U.S. Geological Survey's Stackelberg tracked water at a New Jersey

water-treatment facility, testing it for contaminants when it began as

source water and then after each step of the cleaning process. He found

DEET at every step, in every one of the samples.

The insect repellent's resilience raises questions about whether it

stays in the sediment of streams, and whether fish or birds -- to which

DEET can be toxic -- could be harmed over the long term.

" A little bit seems to go a long way in the environment, " said Dana W.

Kolpin, a research hydrologist with the Geological Survey in Iowa City,

Ia., who has studied DEET.

Ed Hopkins, director of the environmental quality program for the Sierra

Club, said the U.S. EPA should be more aggressive about getting

contaminants out: " They shouldn't be in our water supply, and we need to

do much more to keep them out. "

Said Stackelberg: " You wonder just how many human-related compounds

there are in [a] sample, and what their cumulative effect would be. And

right now, we don't really have an answer for that. "

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