EPA responds to reports of drug-contaminated drinking water

Traces and treatment

18 August 2008 00:00  [Source: ICB]

Pharmaceuticals found in US drinking water spark concern and draw attention to water treatment

THE SIGNIFICANCE of a recent Associated Press (AP) study finding traces of drugs in drinking water across the US remains unresolved, with the US Environmental Protection Agency (EPA) responding cautiously.

"Studies have shown that pharmaceuticals are present in our nation's water bodies," the agency said in a statement. "Further research suggests that certain drugs may cause ecological harm. More research is needed to determine the extent of ecological harm and any role it may have in potential human health effects."

The information available does not suggest that the low levels of pharmaceuticals found in water pose a significant risk to human health, says EPA spokeswoman Enesta Jones. "But their presence in water is a concern, and we are continuing to evaluate their risk to human health," she adds.

Beginning in October 2007, the AP conducted its study for five months, before publishing the results in March 2008.

"Members of the AP National Investigative Team reviewed hundreds of scientific reports, analyzed federal drinking water databases, visited environmental study sites and treatment plants, and interviewed more than 230 officials, academics and scientists," the news agency said.

The team surveyed 50 of the nation's largest cities and a dozen other major water providers. It also surveyed smaller community water providers in all 50 states.

In many localities - for example, Albuquerque, New Mexico Austin, Texas and Charlotte, North Carolina - no pharmaceutical contamination was found.

In others, traces were found of as few as one drug to as many as 56 (Philadelphia, Pennsylvania). They included epileptic and anxiety medications, sex hormones, mood stabilizers and numerous others.

These results are not entirely new. Personal care products as pollutants (PPCPs) have always been present, notes the EPA.

HOW THEY GOT THERE

"Pharmaceuticals have probably been present in water and the environment for as long as humans have been using them," says Jones.

"The drugs we take are not entirely absorbed by our bodies, and are excreted and passed into wastewater and surface water," she explains. "Veterinary drugs, which are used on livestock and domesticated animals are excreted and passed on to waterways. In addition to excretion, pharmaceuticals can end up in water systems through drug disposal practices like flushing down toilets or drains," she adds.

Scientists, however, express growing worries over the presence of so many prescription drugs and over-the-counter medications in a significant portion of drinking water sources. They are unsure of the long-term consequences to human health.

"Recent laboratory research has found that small amounts of medication have affected human embryonic kidney cells, human blood cells and human breast cancer cells," reported AP. "The cancer cells proliferated too quickly the kidney cells grew too slowly and the blood cells show biological activity associated with inflammation."

EARLY WARNING SIGNS

Some scientists stress that research on human health effects is still very limited, although these early warning signs should be taken into account.

One major issue with respect to effects on the environment and health revolves around the difference of PPCPs from conventional pollutants. Drugs are designed with the purpose of interacting with cellular receptors at low concentrations to produce a specific biological effect. Sometimes unintended side effects can occur from drugs interacting with receptors that are not supposed to be targeted. Effects may be subtle because PPCPs in the environment occur at low concentrations, according to the EPA. Also, there are variations in how drugs or PPCPs affect different species.

"Aquatic organisms may be affected differently than people because they live in water and are exposed constantly to any harmful chemicals that may be present. Because of the differences between humans and aquatic organisms, aquatic organisms may be more sensitive than humans to the low levels of pharmaceuticals in water," says Jones.

However, the concentration of these contaminants needed to result in risk to human health or aquatic organisms is not known. There is no "one-size-fits-all," Jones adds.

By: Feliza Mirasol
+1 713 525 2653

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