The next drug problem
Hidden among the well-known problems faced by water professionals — aging infrastructure, dwindling supply — is another emerging issue: rising amounts of pharmaceutical compounds in surface water and drinking water. And, considering the increasing numbers of people being treated with drugs at earlier ages and an aging population taking multiple medications for a variety of health conditions, more of those compounds likely will find their way into the nation’s wastewater facilities.
Early signs of the problem were discovered in US Geological Survey (USGS) research in 1999. Of the 60 pharmaceuticals the agency was testing for, it found 30 of them in 139 streams in 30 states. In addition, 80 percent of the streams had one or more contaminants, 54 percent had five or more, and 13 percent showed 20 or more.
“We can measure over 150 compounds in water alone,” says Dana Kolpin, a research hydrologist and member of the USGS study team. “Now, the big question is, what kind of environmental consequences [do they pose] to terrestrial and aquatic ecosystems and, maybe in the long term, even human health. We just don’t know what the exposure risk is to many of these compounds.”
Determining the effects
Scientists from the Iowa City, Iowa-based USGS, other government agencies and universities are attempting to determine the potential effects of chronic exposure to pharmaceutical mixtures — otherwise known as Compounds of Emerging Concern (CECs) — such as endocrine disruption and the development of antibiotic resistance, in the aquatic environment, soil, plants, animals and humans.
Though the amounts being measured often are in parts per million or parts per billion, many of the compounds are designed to have effects at low levels. “These CECs are active at very, very low concentrations in the water and in the sediments,” says Jeff Armstrong, senior scientist in the Ocean Monitoring Group for the Orange County, Calif. Sanitation District. “It’s not so much the death of the animals [that is a concern], it is reproductive effects or effects on other areas of the endocrine system, the ability to fight off infection or other aspects of reproduction.”
Endocrine disruptors are chemicals that mimic or block hormones or trigger abnormal reproductive responses in fish and possibly in humans. Nevertheless, our ability to measure the compounds is ahead of our knowledge of their long-term effects.
However, some fish in close proximity to wastewater discharge points exhibit multiple sexual abnormalities, such as male fish with deformed testes or low or no sperm counts, for example. Some fish are classified as “intersex” with sex characteristics of both genders. Kolpin says a large proportion of the male fish have either female egg protein or female characteristics.
Following a high number of fish deaths in the Potomac Basin and the Shenandoah watershed between 2003 and 2005, the USGS and scientists from Virginia and West Virginia analyzed samples of 30 smallmouth bass from six sites. A microscopic examination of the fish testes discovered 42 percent of the male bass had developed eggs. A second USGS study found an even higher number of intersex fish — 79 percent. “[In the Potomac, we found] a big portion of the male fish having either female egg yolk protein or female characteristics,” Kolpin says. Douglas Chambers, the study’s lead scientist, says that all water samples contained detectable levels of at least one known endocrine-disrupting compound.
Pacific Ocean flatfish found in sediment near Orange County, Calif.’s Huntington Beach effluent discharge point exhibited similar effects. “We’re finding that male fish are producing [endocrine-disrupting compounds] in concentrations that normal males should not,” Armstrong says. “That means they’re being exposed to some kind of estrogenic compound. We’re finding the fish near our outfall and [the estrogenic compound] seems to be in higher concentrations [there, which indicates] that something’s coming out in the treated wastewater that might be causing this.”
“It’s really not certain what’s going on, but [there is no doubt] that there is evidence of endocrine-type biomarkers in fish downstream from wastewater outfalls,” says Shane Snyder, research and development project manager for the Southern Nevada Water Authority in Las Vegas. “The degree of magnitude of the effect seems like it’s going to be related to the treatment type, the degree of mixing and the mobility of the fish.”
Sources and treatment of CECs
The contaminants may originate from hospitals and medical facilities, vet clinics, pharmaceutical manufacturers, and people using prescription and over-the-counter medications and personal care products. “[Medical facilities] can be a big source of … pharmaceuticals, X-ray and MRI contrast agents and chemotherapy drugs,” Kolpin says. “Maybe they need to have separate wastewater treatment so they’re not just put in with residential waste.”
Designed to remove conventional pollutants, such as suspended solids and easily biodegradable organic materials, most conventional wastewater treatment plants do not remove CECs. The concentration of the compounds that remain in wastewater treatment plant effluent depends on the type of treatment, the specific compounds as well as the concentration in the influent entering the plant.
Techniques for removing compounds from drinking water include advanced oxidation, membrane filtration and filtration with granular activated carbon, and nano-filtration combined with reverse osmosis, which eliminates all the drugs. Each technology serves a function, but each can produce an unwelcome side effect.
Conventional ozone renders certain CECs inactive, but its use comes with a price, Snyder warns. “Ozone creates regulated byproducts — regulated on cancer endpoints. [It’s] great [that] you’re putting in ozone, but what about all the cancer-causing byproducts they form?”
Chlorine, the most commonly used wastewater disinfectant in the U.S., is the least effective in removing CECs. Kolpin’s concern is the creation of chlorination byproducts. The EPA already has set drinking water standards of 100 parts per billion for one group of byproducts, called trihalomethanes, because of their potential to cause cancer. “You may be removing the parent compound [of CECs] but creating these chlorinated degradation products, [and you] may be worse off than when you started,” he says. “Certainly chlorination has the advantages of removing pathogens, but to say that’s the best route to remove [CECs needs to be researched].”
Reverse osmosis (RO) uses large amounts of electricity and produces a highly concentrated wastewater stream. “[RO] creates a stream of concentrated waste, [so] what do you do with the concentrated waste stream that you’ve generated?” Snyder says.
Techniques that combine ozone and granular activated carbon (GAC) are effective for removing industrial and agricultural pollutants, and also improve the water’s taste and odor. The filters get dirty and must be washed periodically, otherwise the water can become infected with cryptosporidium or Giardia.
Before water utilities can choose an effective technology, though, the harmful CECs have to be identified. “First we need to figure out, ‘Do we need to mitigate?’ And, if we do, then we’ll address those larger issues of how to do it,” Armstrong says.
Still, common wastewater treatments can be useful in removing CECs. “The tertiary treatment, like reverse osmosis (RO) or micro- or nano-filtration, removes pretty much 100 percent of [CECs],” Armstrong says. “There’s a lot in the literature that [says] ozonation renders these [compounds] biologically inactive. The problem is doing that on a large scale. [We process] 255 million gallons a day. There’s no way we can do that, so we have to look to other ways to figure out what kind of mitigation strategy’s going to work for us.”
CECs will not be regulated in the near future, at least. “Due to insufficient data [on the occurrence and toxicity], it appears that pharmaceuticals will not be regulated any time soon,” says Snyder, who works with the EPA on its Contaminant Candidate List 3 (CCL3). The substances that will be regulated, however, will be available next summer.
Meanwhile, the Las Vegas Water District has added ozone to its expanded wastewater treatment facility. Ozone was chosen for its disinfection power to prevent a repeat of a 1994 cryptosporidium outbreak in the city that was linked to 32 deaths, as well as for its ability to eliminate CECs. “Ozone is extremely effective for destroying estrogenicity, and that’s where our concern lies for the fish,” Snyder says.
Because 50 percent to 90 percent of ingested drugs are excreted, state and local governments are attempting to involve the public through drug take-back programs to stem the flow at one of its source points. “We’ll deal with that in the treatment plants as best we can, but keeping the extraneous pharmaceuticals out of the environment is where the majority of the action seems to be at the municipal level today,” Armstrong says.
State legislators, too, are becoming more aware of drinking water being contaminated with prescription drugs. California’s Senate Bill 966, requiring every pharmaceutical drug retailer to collect out-of-date drugs for proper disposal, made its way through two committees before being voted down in May.
The public also seems ready to address the issue. In May 2006, the San Francisco Bay Area Pollution Prevention Group collected 3,634 pounds of pharmaceutical waste from 1,500 residents, and South Portland, Maine, recently sponsored a one-day event and collected 55,000 pills. The state’s legislators currently are exploring instituting turn-in, mail-back and other disposal programs.
Making it convenient for the public to participate in drug take-back programs appears to be helping. San Mateo County, Calif., featured repainted (and donated) U.S. Postal Service mailboxes, which made their program as easy to access as mailing a letter. Their pilot program in four locations collected nearly 590 pounds of unwanted drugs in just four months, at a cost of $924, plus the costs of the police to collect the drugs.
Despite the best efforts to control the drugs that enter the wastewater stream, water utilities still can expect challenges to meet growing needs and the delivery of safe drinking water to their customers, including removing CECs. “I’m hoping if we are able to identify certain compounds that seem to be the culprits in potential human health risks, that technology could be developed to mitigate those, rather than take out everything,” Snyder says. “People have the perception that utilities like ours pull from some giant coffer of money and we can do whatever we want to get down to the last nanogram [of contaminant], but the public will pay.”
Patricia Frank is a freelance writer in Beaufort, N.C.
More to learn
Next month, water and wastewater utility managers, scientists and pharmaceutical manufacturers will meet in Providence, R.I., to discuss the state of knowledge about compounds of emerging concern (CECs), needed research and next steps. Regulatory, treatment and analytical alternatives will be explored, including key CEC issues of sources and pathways, and fate and lifecycle analysis.
Conducted by the Alexandria, Va.-based Water Environment Federation (WEF), the July 29-30 symposium is co-located with the WEF Industrial Water Quality 2007 Conference. It is held in cooperation with the Woburn, Mass.-based New England Water Environment Association, the Alexandria, Va.-based Water Environment Research Foundation and the Washington-based Pharmaceutical Research and Manufacturers of America. For more information, visit www.wef.org/CECs.