[Water_news] 4. DWR'S CALIFORNIA WATER NEWS: WATER QUALITY - 6/13/08

Department of Water Resources

California Water News

A daily compilation of significant news articles and comment

 

June 13, 2008

 

4. Water Quality –

 

 

 

Hard to swallow: Do tiny quantities of drugs in drinking water pose a threat to human health?

Lake Oswego Review-6/12/08

By Chris Lydgate

 

One of the most unpalatable environmental stories of the year landed with an alarming splash in March, when The Associated Press reported that water supplies across America are contaminated by trace amounts of pharmaceuticals.

 

Drugs detected in tap water range from mood stabilizers in Southern California to anticonvulsants in New York City to sex hormones in San Francisco. Altogether more than 100 different compounds have been found in water supplies serving 41 million people, albeit in exceedingly small quantities.

 

The AP report came in the wake of several scientific studies showing that America’s reservoirs, rivers and lakes are increasingly contaminated with tiny doses of unwelcome pollutants such as steroids, insect repellent, detergents and plasticizers.

 

Unfortunately, we are not immune. Last week, officials with the Portland Water Bureau told Sustainable Life that inspectors detected extremely minute quantities of two hormones in groundwater samples; previous tests of Portland water found trace amounts of caffeine and pain relievers.

 

At first glance, the appearance of drugs in the water supply seems the perfect example of how modern technology is driving the planet’s ecosystems to the breaking point.

 

“There’s widespread concern,” says Dr. Ilene Ruhoy, a Nevada physician and environmental scientist who has researched the issue for the Environmental Protection Agency. “We’ve got to look at this further.”

 

Ruhoy (who comes to Portland next week to present a lecture titled, “Drugs in the Water: How our Medicine Cabinets are Contaminating Nature”) is one of a swelling tide of scientists looking at the proliferation of “emerging contaminants” such as pharmaceutical compounds and personal care products in the environment.

 

But many experts say there is no evidence that such minuscule traces pose any threat to human health.

 

First, they point out, the contaminants are being detected at extraordinarily minute levels – levels that bankrupt the imagination. For example, the highest concentration of any pharmaceutical ever found in Portland’s water supply was acetaminophen, the active ingredient in Tylenol, which was detected last year at 18 parts per trillion.

 

To ingest the equivalent of two Tylenol pills, you’d have to drink 10 gallons of water a day, every day, for 4,021 years.

 

“It shouldn’t be dismissed,” says David Shaff, administrator of the city’s water bureau. “But it’s a very, very, tiny, tiny amount.”

 

Even at the highest levels detected, and even with the strictest margin of safety, the pharmaceutical compounds so far discovered in drinking water stand at concentrations thousands of times below the therapeutic dose.

 

In a study published in January in the journal Ozone: Science & Engineering, for example, toxicologist Shane Snyder, research and development product manager for the Southern Nevada Water Authority, tested water samples from 20 cities across the country.

 

The most concentrated pharmaceutical he could find was the sedative meprobamate, which has been shown to be toxic in mice; the acceptable daily intake is a mere 180 parts per billion.

 

However, the highest concentration of meprobamate measured by Snyder stood at the level of 42 parts per trillion. To approach the margin of safety, you’d have to drink more than 4,000 glasses of water a day.

 

“From all the data we have in front of us now, we don’t see any impacts on human health from these extremely minute quantities,” Snyder told Sustainable Life.

 

Experts say that pharmaceuticals now are cropping up in water supplies not because pollution is getting worse, but because tests are getting better.

 

“In the ’50s and ’60s, we could detect pharmaceuticals in parts per million,” says chemist Andrew Eaton, laboratory director of Montgomery Watson Harza Laboratories in Monrovia, Calif. “In the ’70s and ’80s, parts per billion. Starting in this decade, we went to parts per trillion, and now we’re pushing it lower and lower.”

 

The technical advances mean that chemists now can find contaminants in water that previously would have been considered pure.

 

Snyder compares the development of better water testing to the evolution of the telescope. “In the early 19th century, telescopes could only pick out a few thousand stars,” he says. “Now Hubble can see billions. But it doesn’t mean they weren’t there before.”

 

A drop in 10,000 buckets

Portland’s water comes from two sources. The main supply is Bull Run, a remote chunk of wilderness on the flank of Mount Hood that feeds a system of rivers, lakes and reservoirs stretching for 102 square miles.

 

Most of the time, the water bureau relies on Bull Run alone, but during severe storms or summer drought it also can draw groundwater from wells fed by underground aquifers.

 

The first hint that pharmaceuticals might be seeping into Portland’s drinking water came in August 2006, when an untreated sample from Bull Run water showed caffeine at 9.2 parts per trillion.

 

Subsequent tests of the groundwater revealed caffeine, acetaminophen, ibuprofen and sulfamethoxazole.

 

This spring, Shaff, the bureau administrator, ordered another round of tests on water from both sources. The Bull Run samples produced no “hits.” The groundwater tested positive for a pair of hormones, estradiol and ethinyl estradiol-17 alpha, but found no evidence of the drugs that were previously detected.

 

“I don’t know why those compounds appeared and then disappeared,” says Yone Akagi, a water quality engineer for the water bureau. “But I am confident our water is safe to drink.”

 

One vexing question is how these contaminants wind up in the drinking water in the first place.

 

Typically, the scenario goes like this: People take medications that pass through their bodies and eventually are washed down the drain; or they flush old pills down the toilet. Either way, the drugs make their way into a wastewater treatment system, which generally are not designed to remove dissolved compounds in such tiny amounts.

 

Finally, the treated water is discharged back into a river, stream or lake that serves – steady yourself – as a drinking source for other communities downstream.

 

Another route is that contaminants seep from landfills or septic tanks into the soil below, and then percolate deep into underground aquifers. Boaters and bathers can also contaminate rivers with sunscreen, insect repellent and various personal care products.

 

None of these routes explains why caffeine would be detected in Bull Run. Water bureau officials say they are puzzled by the result. “I have no idea,” Shaff says. “Did the inspector spill coffee on his hands that morning? Did he breathe on the sample?”

 

Small but dangerous?

It’s worth remembering that certain pollutants, such as endocrine disruptors, have been shown to cause problems for fish and other aquatic species even at concentrations of parts per billion.

 

Furthermore, the Environmental Protection Agency has not established official exposure levels for most emerging contaminants, which contributes to the lingering uncertainty over what is safe.

 

Finally, some researchers worry that although individual pharmaceutical contaminants may all fall below the generally accepted level of concern, together they may impose a cumulative toll on our health.

 

“We live in a sea of chemicals,” Ruhoy says. “Pharmaceuticals are not the only exposure out there.”

 

Nonetheless, local water officials say exotic contaminants pose far less of a potential hazard than familiar headaches such as lead and copper (from old household plumbing) or giardia (from pesky critters that poop near streams.)

 

“Parts per trillion? We lose absolutely no sleep over that,” Shaff says.

 

In fact, he and other water officials fret that the froth over pharmaceutical contamination will divert attention from more prosaic problems, such as aging infrastructure.

 

“There are a lot of issues with drinking water in America,” says Snyder, of the Southern Nevada Water Authority. “In many parts of the country, we have crumbling infrastructure that is 100 years old. The pipes leak, they crack. Those are real issues. In a way, it’s a shame that people are being distracted by tiny concentrations of contaminants when we have such overt problems in our water systems.”

 

Water officials say it is technically possible to build aggressive treatment systems that scrub more pharmaceutical contaminants out of drinking water, but doing so is extremely expensive and can introduce additional problems.

 

Stronger doses of chlorine, for example, would remove many of the offending compounds, but also would raise the level of chlorination byproducts, such as haloacetic acids, which themselves constitute a kind of contamination – rather like loading too much soap in the dishwasher.

 

Even multiple disinfection and filtration won’t yield water that is absolutely pure, experts say. “There is no treatment in the world that can possibly remove every trace of every compound down to parts per trillion,” Snyder says.

 

Meanwhile, detection technology keeps getting better. “The real story here is the advancements in analytical techniques,” lab director Eaton says. “But that doesn’t generate great headlines.”#

http://www.lakeoswegoreview.com/sustainable/story.php?story_id=121303862600044100