I’ll Have a Glass of What You Had Yesterday
Humans are actually less likely to be harmed by traces of detergents and drugs in our drinking water than are other species.
Water is used over and over again.
Karl Linden, an engineering professor at the University of Colorado, would like the public to understand how trace elements of the more than 3 billion prescriptions Americans fill every year can be found in the nation's drinking water.
"The water in the Mississippi is used, reused, treated and served as drinking water many times before it reaches the delta at New Orleans," Linden said.
Water from wastewater treatment facilities is poured back into rivers; effluent from agricultural operations feeds streams; manure used to fertilize fields may find its way into the groundwater; and humans excrete the prescriptions and over-the-counter remedies they've taken into the toilet. (Up to 90 percent of an oral drug can pass through the body unchanged.)
"We are really re-using all our water," Linden said. "If a chemical or pathogen doesn't get removed in our wastewater plants, it is likely getting into someone's water supply."
A cocktail of trace elements appears in water supplies across the nation, including compounds from cosmetics, detergents and toiletries, painkillers, tranquilizers, anti-depressants, antibiotics, birth control pills, estrogen replacement therapies and anti-seizure medications. They are commonly referred to as "emerging contaminants," or PPCPs (pharmaceuticals and personal care products).
Traces of these elements were documented in a recent Associated Press survey of 62 water providers; at least one pharmaceutical was found in the drinking water supplies of 28 major metropolitan areas. Trace levels of as many as 56 pharmaceuticals or their byproducts were found in one water supply. The survey set off alarms around the country, and while there are alarming statistics associated with this, there are also many qualifiers.
Pharmaceuticals have been on the radar of the United States Geological Survey since the early part of this century. A study released in 2002 sampled water downstream from urban areas and found that one or more contaminants were found in 80 percent of the waterways.
Since that study, the Geological Survey has completed about 160 more on the topic. Herbert Buxton, a lead author of the study, notes what several researchers interviewed for this story said: The reason we're able to view this as a problem is simply because we have much better vision. Mass spectrometers are allowing researchers to spot trace elements at as little as a part per trillion.
"When you drop a sugar cube in an Olympic-size swimming pool the concentration is a few parts per billion," he says. "We're talking about parts per trillion (today's detection). The other side of the coin is some of those are active at very low levels —particularly the ones that are hormonally active or that mimic hormones."
Trace elements of these compounds have been in our water supply for some time. Many researchers are saying the nanogram levels at which PPCPs are being found at are unlikely to harm people, although further study is needed.
For aquatic species, it's another story.
Several species of fish have shown signs of feminization and some studies have found endocrine-disruptive processes that could threaten the survival of species.
James Lazorchak, manager of the Environmental Protection Agency Aquatic Research Center, authored a study with Mitchell Kostich looking at the amounts of 371 active pharmaceutical ingredients consumed in the United States. They developed a risk analysis and predictions for what exposure to the ingredients might do to humans and aquatic species.
Lazorchak says the next steps are to test the study's predictions by analyzing treated wastewater effluent using new analytical chemistry methods and then exposing test subjects in the lab to the most commonly found pharmaceuticals at the levels detected.
Results could determine what sorts of ingredients threaten aquatic species, he said. Like other researchers, Lazorchak notes the threat to humans may have been overplayed by the AP survey. "At the concentrations that are being found out there, you'd have to drink 250,000 gallons of water a day to get one dose (of some of the ingredients)," he said.
Lazorchak was a co-author of a well-known Canadian study (www.umanitoba.ca/institutes/fisheries/) in which researchers dripped the active ingredient in birth control pills into a near pristine Canadian lake at levels commonly found to damage aquatic life. After about seven weeks, male fathead minnows took on feminine biological and behavior attributes and, after two years of dosing, the minnows stopped reproducing. The result of three years of dosing was a near extinction of the species.
It's not just fish. The AP survey documents other studies that have shown kidney failure in vultures, impaired reproduction in mussels and inhibited growth in algae caused by intake of pharmaceuticals in the aquatic environment.
Another concern is that bacteria might develop a resistance to antibiotics after exposure to the drugs in water sources. Monica Tischler, a biology professor at Benedictine University near Chicago, has been able to isolate 205 types of bacteria in the feces of Canada geese, many of which showed strong resistance to streptomycin, erythromycin, vancmycin, tetracycline and penicillin-family drugs.
Her current study will determine if bacteria in the guts of goslings are similar to adults (which are able to fly and are exposed to other environments, including agricultural areas). If the bacteria isolated from goslings show a similar resistance to antibiotics as the adults, it is likely that this trait has been passed on through mutations or gene transfer.
Citing the rise of multi-resistant tuberculosis, Tischler noted that antibiotic-resistant bacteria are a long-standing concern. "If there are antibiotics pervasive in the environment that foster resistance, then we don't necessarily have the tools to help those of our loved ones who are sick," she said.
In agricultural areas, animal treatment is a major contributor to the contaminant load in waterways. An estimated 40 percent of all antibiotics in the United States are fed to cattle as growth enhancers. Growth hormones for livestock have been used for decades and veterinarians are increasingly treating animals with pharmaceutical compounds originally developed for human consumption.
The AP survey also created a stir among the nation's water management and federal agencies, and the Environmental Protection Agency currently does not require testing for pharmaceuticals in drinking water.
It's most recent regulatory action concerned a more traditional water problem, the intestinal parasite cryptosporidium. The EPA and water managers have been gearing toward methods to address that diarrhea-causing bug.
That fight demonstrates some of the challenges facing water managers. Chlorination, the nation's most common water treatment method, is basically a disinfectant and does not remove PPCPs. Other methods of water purification — ozonation, oxidation, exposure to ultraviolet light, carbon filtering, membrane technologies, reverse osmosis — are effective on various contaminants but are more expensive and often need to be used in combination to remove a significant part of the organic contaminants.
Because some pharmaceutical compounds are "hydro-loving," Linden said, they are not easily removed during water treatment.
The United States might look abroad for help. European countries are ahead of the curve on the problem, partly because they were among the first to identify PPCPs in their water supply. Other factors are their chosen water treatments (chlorination hasn't been a common method of treatment) and a willingness to pay more for clean water in the face of a growing need.
In the next part of this series, we'll look at two treatment facilities that are leaders in addressing not only PPCPs in water but also reuse of wastewater.
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