Emptying Our Medicine Cabinet into Our Waters
by Peter Montague

When you pop a pill, it doesn't stop there. Pharmaceuticals given to people and to domestic animals - including antibiotics, hormones, painkillers, tranquilizers, and chemotherapy drugs given to cancer patients - are turning up in surface, ground and tap water. Increasingly, large quantities of drugs excreted by humans and domestic animals are being distributed into the environment by flushing toilets and by spreading manure and sewage sludge onto and into soil.

German scientists report that anywhere from 30 to 60 drugs can be measured in a typical water sample. The concentrations of some drugs in water are comparable to the low parts-per-billion (ppb) levels at which pesticides are typically found.

What is the long-term effect of drinking, day after day, a dilute cocktail of pesticides, antibiotics, pain killers, tranquilizers and chemotherapy agents? No one knows. It is simply beyond the capabilities of science to sort out the many chemical interactions that could occur in such a complex chemical soup. The only solution to such a problem would be prevention.

The first study that detected drugs in sewage took place at the Big Blue River sewage treatment plant in Kansas City in 1976. The problem, duly recorded in scientific literature, was then ignored for 15 years. In 1992, researchers in Germany looking for herbicides in water kept noticing a chemical they couldn't identify. It turned out to be clofibric acid (CA), a drug used to reduce cholesterol levels in human blood. Clofibric acid is a close chemical cousin of the popular weed killer 2,4-D. Based on that early discovery, the search for clofibric acid (CA) in the environment was stepped up.

Since 1992, researchers in Germany, Denmark and Sweden have been measuring CA and other drugs in rivers, lakes and the North Sea. To everyone's surprise, it turns out that the entire North Sea contains measurable quantities of clofibric acid. Based on the volume of the Sea, which is 12.7 quadrillion gallons, and the average concentration of CA, which is 1 to 2 parts per trillion (ppt), researchers estimate that the Sea contains 48 to 96 tons of clofibric acid with 50 to 100 additional tons entering the Sea each year. The Danube River in Germany and the Po River in Italy also contain measurable quantities of clofibric acid. Of more immediate concern to humans is the finding that tap water in all parts of the city of Berlin contains clofibric acid at concentrations between 10 and 165 ppt. The water supplies of other major cities remain to be tested.

Individual scientists within the US Food and Drug Administration (FDA) have been concerned about this problem for a decade, but so far the FDA has taken the official position that excreted drugs are not a problem because the concentrations found in the environment are usually below one part per billion (ppb).

Post-Flush Pollution
Thirty percent of the drugs manufactured between 1992 and 1995 are lipophilic, meaning that they tend to dissolve in fat but not in water. This gives them the ability to pass through cell membranes and act inside cells. Unfortunately, it also means that once they are excreted into the environment, they enter food webs and concentrate in predators. Many drugs are also designed to be persistent, so that they can retain their chemical structure long enough to do their therapeutic work. Unfortunately, after they are excreted, such drugs also tend to persist in the environment.

A landfill used by the Jackson Naval Air Station in Florida contaminated groundwater with a plume of chemicals that has been moving slowly underground for more than 20 years. The drugs pentobarbital (a barbiturate), meprobamate (a tranquilizer sold as Equanil and Miltown) and phensuximide (an anticonvulsant) are still measurable in that groundwater plume.

When a human or an animal is given a drug, anywhere from 50 percent to 90 percent of it is excreted unchanged. The remainder is excreted in the form of metabolites - chemicals produced as byproducts of the body's interaction with the drug. Researchers report that some of the metabolites are more lipophilic and more persistent than the original drugs from which they were derived.

When a new drug is proposed for market, the FDA requires the manufacturer to conduct a risk assessment that estimates the concentrations that will be found in the environment. If the risk assessment concludes that the concentration will be less than one ppb, the drug is assumed to pose acceptable risks. FDA has never turned down a proposed new drug based on estimated environmental concentrations, and no actual testing is conducted after a drug is marketed to see if the environmental concentration was estimated correctly.

German chemists have found that many drugs can be measured at environmental concentrations that exceed one ppb. There is ample evidence that some chemicals have potent effects on wildlife at concentrations far below one ppb. For example estradiol, a female sex hormone (and a common water pollutant), can alter the sex characteristics of certain fish at concentrations of 20 parts per trillion.

Another problem resulting from drugs in the environment is bacteria developing resistance to antibiotics. Antibiotics are only useful so long as bacteria do not become resistant to their effects. Hospital sewage systems discharge substantial quantities of antibiotics into the environment. Bacteria exposed to antibiotics in sewage sludge or water have an opportunity to develop resistance.

The Solution is Not Dilution
Hospitals and the health care industry are the major sources of these problems, especially antibiotics and chemotherapy drugs. Health Care Without Harm, a large national coalition of environmental and health groups, might consider tackling this difficult but important problem.

Sewage sludge provides a major pathway by which drugs enter the environment. Until the drug problem is understood and controlled, it provides a solid scientific rationale for labeling sewage sludge a dangerous soil amendment, the use of which should be forbidden.

For a long time, people have worried that the world was going to run out of natural resources. It is now apparent that we have run out of places to throw things away.

Peter Montague is a member of the National Writers Union, UAW Local 1981/AFL-CIO).

Reprinted from Rachel's Environment & Health Weekly [Environmental Research Foundation, PO Box 5036, Annapolis, MD 21403-7036, 1-888-2RACHEL, (410) 263-1584, fax: (410) 263-8944. Rachel's is a free service: tax-deductible contributions to ERF are always welcome].