Antibiotics: Study will look for traces in streams


You take an antibiotic to knock off a lingering sore throat. Before long, a trace of that drug ends up in the local sewage treatment facility.

Add to that the traces of antibiotics consumed by dozens of other people in the community. Eventually, water at the sewage lagoon is discharged and now traces of the drugs are flowing south in Bean Creek.

That’s the human contribution; agriculture makes its own impact.

The National Academy of Sciences estimates that more than two-thirds of the antibiotics sold in the United States end up on the farm—mostly fed to healthy animals as a growth stimulant. The Animal Health Institute claims that only about 36 percent of U.S. antibiotics are used by agriculture.

In either case, there’s plenty of room for agriculture’s contribution to the presence of antibiotics in surface water. Most of the farm-based drugs are available without a prescription and are mixed with feed. The US EPA estimates that 80 percent of antibiotics administered orally to animals passes through the body unchanged. The manure is then used as fertilizer on fields.

Studies by the United States Geological Survey have detected low levels of veterinary medicine in soil, surface water and ground water. Overall, antibiotics from all sources were detected in 48 percent of all streams tested in a nationwide survey.

A study scheduled to begin this spring will check for antibiotics in the five river systems that pass through Hillsdale County, including Bean Creek.

The Hillsdale office of the Community Action Agency (CAA) was awarded a $15,877 grant from the Michigan Department of Environmental Quality’s Clean Michigan Initiative. The project was funded through the “emerging issues” section.

Christie Cook of the CAA’s Hillsdale office said that she read an article several years ago about the presence of antibiotics in surface water and it piqued her interest in local conditions. There are no antibiotics removal processes in place, she said, and there are no standards established.

“They pretty much pass through a body unchanged and end up in surface water,” Cook said.

The CAA project will operate with oversight by the DEQ, and data collected will be forwarded to the agency for review.


Water samples will be collected from 16 sites in Hillsdale County to include the watersheds of five rivers: St. Joseph, Kalamazoo, Grand, Raisin and Bean.

Bean Creek tributaries include Clear Fork, north of Territorial Road; Toad Creek near US-127; Lime Creek, south of Prattville Road; St. Joseph Creek at Beecher Road; and Fisk Drain at Addison Road. The River Raisin site is located at the outlet of Lake Sommerset.

Sites were chosen to include municipal and agricultural sources.

“We’re trying to coordinate collection times to coincide with municipal wastewater discharge periods,” she said.

Testing for antibiotics involves a more complicated procedure than other typical tests, such as for bacteria.

“It’s quite expensive to test for these kinds of drugs,” she said.

One of the least expensive tests—for penicillin—cost $140 for each sample.

Penicillin is one of seven antibiotics chosen for the study. Others are bacitracin, chlortetracycline, Coban, neomycin, oxytetracycline and Rumensin.

Some of the drugs are specific to human use, some to agricultural use, and others are used by both.

When samples are drawn, collectors must follow stringent guidelines to prevent contamination. For example, people must be free of antiperspirant, antibiotics and caffeine.

The CAA contributes $7,308 to the project cost, but a portion of that can be made through labor. The Hillsdale County Commission and the drain commission have both contributed to the effort.

Cook can’t guess what the study might turn up, but she’s eager to contribute data about the topic.

“I think it’s an issue of real concern that’s just coming to the forefront,” she said.

  - March 17, 2004

Is it a problem? 

There’s no question about the presence of antibiotics in the nation’s waterways, but is that a problem?

That’s where the controversy kicks in.

The main area of concern is the emergence of “superbugs”—bacteria that have developed a resistance to common antibi

otics. The fear among many scientists is that the overuse of antibiotics will increase the prevalence of superbugs. A strain of bacteria that isn’t affected by existing drugs could cause a major public health emer

gency. At the worst, some researchers say, plague-like conditions could return such as those prevalent in the in Middle Ages.

Since antibiotics are used routinely to stimulate growth in healthy farm animals, one camp points a finger at modern agricultural practices as a source of trouble.

Many agriculture experts disagree. Dr. David Price, a consultant to “Feedlot” magazine, wrote a series of articles in 2000 that claims the livestock industry is serving as the scapegoat. The real problem, he claims, is the overuse of human antibiotics.

Price says there is no evidence than an

imal antibiotics lead to bacterial resistance to the drugs used by humans. He cites a paper by the federal Centers for Disease Control that claims an estimated 50 million unnecessary prescriptions are written by physicians every year, largely to prevent lawsuits and to retain patients. Price writes that prescriptions are frequently written for a disease that will be unaffected by the drug, but it satisfies a patient’s desire for treatment.

However, some drugs are used by both humans and farm animals, such as variants of cipro. Two years ago, McDonald’s restaurant–the largest buyer of meat among fast food outlets—stopped buying poultry treated with a class of antibiotics that includes cipro. Other restaurants have followed suit.

Now, McDonald’s is taking its concern a step further by giving purchasing preference to producers that comply with guidelines to reduce the use of antibiotics in cattle and pigs. Many dairy cattle are rou

tinely fed an antibiotic to improve feed efficiency and promote weight gain.

A study by the U.S. Department of Agriculture in 2001 found that nearly 83 percent of nursery age pigs are fed antibiotics for growth promotion and disease prevention. The most common drug is chlortetracycline.

Generally, antibiotics are used in feed to promote growth and prevent disease. Injected drugs are used for disease treatment.

In the late 1990s, the European Union banned the practice of feeding medically important antibiotics to farm animals for any use other than disease treatment. American agriculture officials fear the same thing could happen here.

The “Preservation of Antibiotics for Human Treatment Act” was introduced in both the U.S. Senate and House in 2002. The proposal gained wide support among medical organizations, but it failed to make it into law.

A University of Illinois study determined that antibiotic use by hog producers equates to a nine percent higher profit margin. Eliminating the use of antibi

otics for healthy animals could represent a loss of profit for drug companies totaling $2 billion annually, according to a study by the National Academy of Sciences.

At the supermarket, it would mean an estimated increase of $9.72 a year for every meat-consuming American.

Fish on Prozac. Frogs on estrogen.

Anti-depressants, phthalates from shampoo and cosmetics, painkillers, beta-blockers—there are far more than antibiotics showing up in lakes and streams.

Drugs make an unglamorous entry into the wastewater system. More than half of the active ingredients in medication pass through the body unused and into the toilet. In addition, outdated and unused drugs are often flushed for disposal.

Estrogen—from birth control pills and hormone replacement drugs—has long been suspected as contributing to sexual oddities in the animal world, including the presence of creatures with both male and female characteristics. But since other contaminants were thought to disrupt the endocrine system, researchers have had a problem making direct connections.

Last year, a Canadian scientist reported on a three-year study that searched for the effects of estrogen from birth control pills. About a third of the males of one species of fish began growing eggs. Another species nearly died off because reproduction stopped.

The feminization of the male fish has scientists wondering about the effects of estrogen on other animals, including humans.

A test involving a synthetic estrogen and captive trout showed an effect in fertility at levels even lower than that measured in many rivers.

Similarly, fish in the wild are found with traces of Prozac and other common anti-depressants. Traces of the drug accumulates in the brain, liver and muscles. In lab sit

uations, scientists have found developmental problems in aquatic life that's attributed to anti-depressants.

Water quality standards for the presence of medication and phthalates has not been established, nor are wastewater treatment facilities capably of filtering out the impurities.