February 16, 2006
Americans are prescribed millions of doses of prescription drugs every year. Livestock are given millions more. But after the pill has been swallowed or the injection taken, the active components of the drugs do not become inert or completely absorbed by the body.
One study found that 80 percent of streams tested contained antibiotics, steroids, synthetic hormones or other common drugs.
Far from disappearing, the drugs are excreted and now, scientists are finding, prescription drugs are showing up in our ground water, soil, waterways and even our drinking water. That's because our conventional sewage treatments may not be looking for drugs, and certainly don't always remove them.
Adding to the problem are prescription drugs that aren't used, then are flushed down the toilet or deposited in landfills - ultimately ending up in the environment.
This so-called "pharmaceutical pollution" could have major implications on wildlife, agriculture and humans - yet is only beginning to be studied.
"This is an important new research area," said A. Lynn Roberts, leader of a Johns Hopkins team that began a study to determine the scope of pharmaceutical pollution in the United States. Roberts continued:
"Over the past few years, scientists in Europe have found pharmaceuticals in natural waterways, sewage treatment effluents and even in drinking water. Yet until this year  there have been virtually no scientific studies examining this issue in the United States. It's important that we begin to look at this because there are many ways in which pharmaceuticals in the environment could produce undesirable effects on aquatic organisms or even humans."
How Widespread is the Problem?
Current estimates are still being gathered, but a study conducted in 1999-2000 by the U.S. Geological Survey (USGS) found that most waterways contain at least some antibiotics, steroids, synthetic hormones or other common drugs. Out of 139 streams in 30 states, they found:
*About 80 percent contained trace amounts of contaminants
*Half the streams contained seven or more chemical compounds
One-third of the streams contained 10 or more compounds
* One water sample contained 38 chemicals
"We're not talking about rampant dumping," said one USGS survey official. "We're looking at the effect of normal existing usage for these different chemicals."
Just how many drugs are we using currently? A lot. Here are some statistics just for antibiotics (not including any other types of drugs):
*Humans consume 235 million doses of antibiotics each year.
*Livestock and poultry producers administered more than 21 million pounds of antibiotics to animals in 2004 alone.
When a drug is taken, experts say up to 90 percent may be excreted back into the environment, unchanged.
What kinds of drugs -- and to what extent -- are currently out there is anyone's guess. Padma Venkatraman, a postdoctoral fellow at Johns Hopkins who is part of the research team, believes the drugs most likely to be found at "toxicologically significant levels" include:
"We're trying to make an intelligent guess as to what's out there in the environment and what's probably toxic," Venkatraman said.
Antibiotic-Resistant Bacteria on the Rise
Up to 90 percent of a drug you consume may be excreted -- unchanged.
Just one problem stemming from pharmaceutical pollution is antibiotic-resistant bacteria. When drugs are excreted in waste, the compounds linger in the environment. In the case of livestock waste, the antibiotic-laced manure is spread directly onto farm crops as fertilizer. From there it may run off into nearby streams.
The result is that bacteria is able to mutate into strains that are resistant to the widely spread antibiotics, paving the way for infections that cannot be easily cured.
According to the Centers for Disease Control and Prevention, about 2 million people in hospitals get infections each year, which cause 90,000 deaths. Of these, more than 70 percent of the bacteria that causes these infections are resistant to at least one common antibiotic that is typically used to treat them.
Health Problems Remain a Mystery
"Little is known about the potential interactive effects" from complex mixtures of waste contaminants in the environment, according to USGS.
For instance, Roberts pointed out that antidepressants work by altering levels of serotonin. However, serotonin causes many aquatic creatures to spawn. The result could be that prescription drugs may alter breeding cycles in the wild. Further, drugs can have major impacts on developing fetuses in humans. If small amounts showed up in drinking water, it could cause birth defects or other problems.
"Pharmaceuticals have high biological activity," Roberts said. "We may be able to tolerate them for a short period of time, but that doesn't mean they won't hurt us -- or developing fetuses or aquatic organisms -- at higher concentrations or over a long period of time."
There is good news, and that is that attention to this issue is growing, and so is the drive to find out just what types of problems may be occurring.
The USGS agrees, stating in their report that "protecting the integrity of our water resources is one of the most essential environmental issues of the 21st century."