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By Pete Hildebrandt
At the end of the last decade a new acronym appeared: PPCP. PPCPs, or pharmaceuticals and personal care products, encompass an extensive number of chemical substances, including prescription and over-the-counter therapeutic drugs, fragrances, cosmetics, sunscreen agents, diagnostic agents, nutraceuticals, and biopharmaceuticals, among many others.
We use PPCPs every day, yet most of us rarely wonder what happens to these substances after the shower is turned off or the toilet flushed. But in the last 10 years the issue has emerged as a concern for the EPA and the USGS. According to the EPA, the conventional priority pollutants had most of our attention for the previous 30 years. The accelerating development of new PPCPs and prescribing of drugs has served to increase PPCP prevalence in the environment.
Early USGS Studies Of PPCP Concentrations
In 1999 the US Geological Survey did a small study with the CDC near Atlanta, GA, to determine the health impact from PPCPs, according to Elizabeth Frick, USGS hydrologist in Georgia. Effects studied included those on effluent downstream of wastewater treatment plants as well as treated effluent itself.
In addition to this study, the USGS also conducted a study in conjunction with the National Park Service along the Chattahoochee River. Though the emphasis of the study was microbial, they also looked at some wastewater tracers at base flow and high flow. Studies came in 2000 and 2001, followed by studies of drinking water intakes in 2002 and upstream major effluent discharge and a proximal at a distal site downstream.
“Ongoing, we have a huge number of wastewater tracer samples that have been collected for a project with the city of Atlanta, looking at what’s in the stream. None of the sites are downstream of treated effluent, though some are downstream of CSOs [combined sewer overflows],” says Frick. “Initially, in 1999, people started looking for data on PPCP occurrence. The CDC was interested in looking at treated drinking water. Now we’ve started to narrow things down to streams, groundwater or drinking water intake.”
The National Water Quality Assessment (NWQA) program has not yet touched pharmaceuticals or antibiotics, according to Frick. But they have done the organic wastewater tracers in a series of source water quality assessment studies.
“There are many of us working on this issue,” says Frick. “But some, like me, are working on it regionally. Our goal is to get a good cross-section of the various types of water treatment. The catch is that the influents are different; this makes an apples-to-apples comparison very difficult because different utilities do have differing source waters.
“The whole gist of things is, whatever humans use, some percent of that gets returned to the environment. Though some of the them are referred to as ‘emerging contaminants’, many are not new compounds. It’s simply that now we have developed different lab methods enabling us to analyze them at the low concentrations at which they occur. They’re not new, but our ability to look for them is new.”
The hydrophilic compounds dissolve in the water and hydrophobic tend to accumulate in animal tissue and sediment. But you must know the chemistry behind them in order to know where to look.
“This is a huge issue,” says Frick, “much more complicated than most people can imagine. It is certainly easier not to place PPCPs in the hydrological cycle than to have them go in, dissolve and then to worry about having to remove them. But from a drug enforcement standpoint, things are extremely regulated and complicated; I personally feel placing pharmaceuticals in the water system is one of the worst things we can do, but the other options are nearly as problematic. In a hospital system, with everything well-regulated and controlled, recycling and reuse works much better; we’re not all in the hospital, though.”
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| Many treatment plants were built before PPCPs became part of the equation. |
In September 1998, a small group of USGS scientists had an internal workshop to discuss which scientific questions would take us into the next century. At that time papers coming out of Europe indicated certain pharmaceuticals and other types of compounds were showing up in European water sources.
“This was a wake-up call for us, to realize we had no clue about what the environmental currents for many of these compounds were in the US,” says Dana Kolpin, research hydrologist with the USGS in Iowa City, IA. “One of the outcomes of that workshop was that some funding was set aside to start looking at pharmaceutical compounds. A number of chemists decided which set of compounds they would study while I worked on coming up with a network in which to search for the compounds.”
Though the USGS knew this could definitely be a groundwater issue, it decided to first concentrate on streams, coming up with a cross-country network to study. “With our limited funding, our plan was to approach the so-called worst-case streams, to begin to see if problems existed,” says Kolpin. “We really hit the ground running. Research started within months of our initial decision to study the issue. Things have only continued to grow and evolve in this area and to broaden, both the look for compounds and the places they’re found.”
Groundwater studies followed the stream studies, and in 2001 Kolpin’s group studied the variety of sources for drinking water, and the raw water entering plants for treatment.
“We’re not quite to the level of publishing a journal article on our findings yet, but that’s coming,” says Kolpin. “Our ongoing research studies the movement of PPCPs once they’re discharged into the environment, as well as effects. We’re trying to look at this as a holistic source-to-receptor type research, even though, early on, things were heavy on the methods and occurrence side. Those things still continue, but we’re also trying to expand and go at the issue from a broad range of angles and questions.”
Since the USGS is a non-regulatory agency, its data feeds into the EPA, where it is used to determine if these compounds need to be added into any types of regulatory aspects in terms of not discharging or making sure removals are down to certain prescribed levels in treated waste. Things haven’t reached that point yet, according to Kolpin. “But I wouldn’t be surprised if some of these compounds are added to a regulatory list.”
Surprises in what the USGS found came not from the existence of PPCP compounds in water samples, but in the mixtures of compounds found: typically seven different compounds and in some single samples up to 40 different substances. “It’s hard enough studying individual compounds,” says Kolpin. “But when you find a cocktail of many different substances, things get even more complicated.
Early on, the focus was on water, but now research is also spotlighting streambed sediments where even higher concentrations may be found. “The entire system—not just the water—must be studied to understand what’s going on,” says Kolpin. “We’re currently grappling with things such as skewed sex ratios in fish or male fish showing up with female characteristics in streams around the country.”
Much higher concentrations of compounds are being found in the biosolids in sludge from municipal plants. This issue is clearly one involving more than simply water supplies, according to Kolpin.
“The sludge from biosolids is applied to land surfaces as a source of nutrients, and that’s a logical thing to do with that; but now we understand that there are other things in the sludge, much higher PPCP concentrations,” says Kolpin. “Does that necessarily have a toxic effect? We don’t know yet. But now we know it’s in there, being applied to the land surface, and we’re doing research to determine if it degrades rapidly in the soil or is bound tightly, is infiltrating the groundwater or is being absorbed by worms and taken up into the food web.
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| A lab boat tests the waters. |
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| Some attempts to round up unused
drugs have been made. |
“We just need to understand what’s going on to see if we do need to make some changes out there. With all our studies so far, we are trying to provide baseline information; we’re not trying to make any statements of effects. We received some criticisms basically asking why we were spending all this funding before effects were even known. We replied that these studies should be done to see if those substances are even present in order to determine if treatment for them should even take place. In reality, it must be approached from both directions—from the toxicology and from the treatment end of things.”
On the Home Front
Triclosan, a common ingredient in antibacterial soaps, has also presented problems. Recent research has shown it to be an endocrine disruptor in tadpole research. Kolpin’s research tested the levels of such compounds in the stream water to just within the levels that affect tadpoles. “Having that data was crucial and helped in justifying the approach we’re taking of looking at many compounds to provide baseline information for scientists and the public to draw upon,” says Kolpin.
“In collaboration with the Colorado School of Mines, 30 septic systems in the Front Range area were studied, including home systems, elementary schools, apartments, and convenience stores. The study yielded findings on what concentrations of compounds were present in these settings.”
Four wastewater treatment sites, each characteristic of what is used today, are being sampled regularly throughout the seasons to determine how the PPCP waste may change: Winter may yield more cold medicine compounds in waste streams, for example, or drugs used by the elderly, a group which typically tends to use more medicines, may be found to follow the pattern of their migrations in winter or summer, according to Kolpin.
A wide variety of research is taking place in the area of PPCPs, by other agencies in addition to USGS, including NOAA, EPA and universities to some extent, on a smaller scale. USGS, with offices in every state in the country, is especially able to study this issue on a national level.
“When most people think of the USGS they think earthquakes and volcanoes, but we do have a large water quality component and are trying to collaborate and integrate with biologists to study the same systems,” says Kolpin. “We’ve already published over 100 papers on this topic but over the next few years there will be even more work done, with more questions raised.
“We’re not trying to sensationalize things, but rather just trying to provide information in order to understand if there are any regulations or treatment technologies needing to come into play.
“This topic has really caught attention because it’s something everyone is directly involved in; caffeine, headache medicines and other things used in our daily lives have made people realize they really are contributing to this growing problem. What we dispose of with unused or expired medications is probably a small piece of the problem, but still it is a piece and even though it may not be solving everything, it’s the easiest piece to take care of.”
Kolpin has seen more and more involvement around the country in so-called take-back mechanisms for drugs as well as Web sites citing the initial research on PPCPs the USGS was engaged in. “It’s good to see that our data is starting to affect public perceptions to some degree.”
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| Researchers gather samples from a
waterway. |
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| USGS scientists use a barge-shocker to collect fish. |
Fishy Business
More and more research is finding downstream effects on fish from estrogen products in the wastestream. More feminization in male fish and androgynization in female fish have shown up in studies. These are quite potent compounds in levels down to parts per trillion.
“It isn’t only the compounds in synthetic hormones having an effect, but also simple human hormones concentrated by high population densities and wastewater treatment plants; everyone normally excretes testosterone and estrogen,” says Kolpin. “Also many compounds mimic hormones, including pesticides and detergent metabolites. It’s that cocktail of toxic compounds, either estrogenic or androgenic that will require great scrutiny over the coming years.”
Kolpin is quick to point out that wastewater treatment plants are not really at fault for this problem. “Wastewater treatment plants are in compliance; we aren’t saying they’re negligent,” says Kolpin. “They are doing what they’re supposed to do. It’s just that these compounds were not part of the equation when these plants were constructed. We need to understand that and then when the EPA makes its regulatory decisions, it can ask that the most critical substances be removed, rather than everything—which is hardly achievable, let alone economically feasible.”
The growing number of fish kills in the Potomac and Shenandoah River Basins needs further study. Also, fish intersects (where one sex shows characteristics of both sexes) and whether they are tied together or two different situations, needs to be determined. Questions remain as to whether this is affecting the long-term reproductive ability of Smallmouth bass or other game fish.
In the Boulder Creek, upstream of the Boulder, CO, wastewater treatment plant, researchers are finding roughly 50-50 males to female of one fish species, the native white sucker. But downstream of the plant the ratios shift to 80% females to 10% males and 10% intersects, according to studies by the USGS.
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| Ozone technology plants are economically viable as
well as being an effective means for treating PPCPs. |
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| To determine water travel time, a harmless
flourescent dye is being placed in
a stream. |
“For fish, a minute amount of the hormones found in birth control pills, may be having effects not found in humans,” says Kolpin. “For other animals, there are many things we simply don’t know about how these compounds are influencing them yet.”
Western Community Studies Ways To Deal with PPCPs
Much of this issue comes down to the fact that many of these compounds now being found have been in water systems for some 30 years or more; but we’re only now being able to study them, as the analytical capabilities to look for them have come about, according to Karin North, associate engineer for Palo Alto, CA’s Environmental Compliance Group. Added to the capability to be able look for them is the question of the levels of the compounds we need to be worried about, versus which concentrations are acceptable or within the limits of safety.
“We are really having a hard time looking at things chemical by chemical, as well as the fact that there could be a synergistic effect with many of these compounds,” says North. “One chemical may not affect an organism, but the combination of a few could be having an effect.”
This is also not a typical dose-response curve where effects are found with an increase in the amount of toxins. “For many of these organisms, when the concentration is very small, they don’t recognize the substance as a foreign object and they’ll let them into their cells,” says North. “That’s when it can mimic what they have naturally in their system, something known as endocrine disruption. When something is found in a larger concentration, the cell realizes this is something which should not be there and it shuts off without letting the foreign chemical in. Despite the feeling that something in parts per trillion must be harmless, scientists are actually finding effects from substances in those concentrations.”
The conventional view was to look at whether something, such as toxins or microorganisms, caused death. Now there may be a variety of end results.
“Dealing with these contaminants requires a multiple treatment train technology approach which must be applied,” says North. “For a typical tertiary treatment plant you may need nano, ultra, UV light treatment and even reverse osmosis. But the problem is you are simply changing what media the compounds are now in; you’re not destroying them. From RO, for example, you still have a concentrated brine waste product containing the PPCP compounds.”
Orange County, CA, has a multiple treatment train including RO for the water, which it’s using to recharge its groundwater aquifers. There is not just one technology to destroy everything, according to North. “That’s the hardest thing to deal with. No matter how you’re modifying your treatment train, you still have to think about concerns with the end product: Is it going to be used for drinking water? Discharge into a surface water body or reclaimed water uses such as agriculture? It’s not cut-and-dried and is expensive as well.”
Looking for Solutions
Attempts to have a program where unused drugs can be taken or mailed back to pharmacies are being pushed for. National efforts to deal with the problem are taking place through a dialogue started by the Products Stewardship Institute (PSI). But currently, because of rules and regulations of the Drug Enforcement Administration, it is difficult to hold collection and incineration events for expired or unused drugs, as it is cost prohibitive. According to DEA’s interpretation of the rules and regulations, the only person who can receive a controlled substance, such as codeine, Ritalin, Vicodan, or Percoset is a law enforcement officer. But this is only about 10% of the pharmaceuticals often collected. “That’s the biggest hindrance to collection programs at pharmacies,” says North. “But we’re working on that. A lot of agencies are holding collection events anyway, either doing it with law enforcement agencies or with the statement that they don’t accept controlled substances. We need to find a solution to this issue.”
“Drug collection programs might at least get the ‘low-hanging fruit.’ Historically most people were told to flush their medications,” says North. “Our wastewater treatment plants are designed to treat biological waste—not synthetic organics. We have all these wonderful organisms expert at breaking down human waste, not chemicals.”
North asserts there is no answer yet to the question of just how many of the compounds in the wastestream are from medications that have gone through the human body and been partially metabolized as opposed to how many are simply drugs flushed down the toilet.
“In Europe, their approval programs for pharmaceuticals requires that companies producing such products prove that their product will cause no harm to the environment, before it’s placed on the market,” says North. “Whereas in this country manufacturers of chemicals are protected; a government agency must actually prove that a substance is causing harm before it’s pulled off the market.”
In terms of pharmaceuticals, if a so-called back-of-the-envelope calculation proves their compounds will not end up in the environment at a concentration of less than one part per billion, then no further testing is required.
“Well, most pharmaceuticals found in the environment are in parts per trillion,” says North. “But effects even at those levels are being found. This is another area of the rules and regulation picture that we need to see if we can change so manufacturers are insuring their products aren’t going to cause environmental harm.
“Our thinking is that once we gather this data on these substances, perhaps we can approach the pharmaceutical companies and ask them to help us pay for their cleanup; that’s the ultimate goal. When you come down to it, the pharmaceutical companies produce a product designed to go in and mimic things happening in your body. It makes sense that if it gets out into the environment, it’s going to cause harm.”
Some might think of the case of something such as a paint manufacturer that must clean up any toxins it has released into the environment. One cannot help but ask: Should drug makers be any different and not be held accountable?
Leading Edge Treatment For PPCPs In Las Vegas, NV
Shane Synder, research and development project manager with the Southern Nevada Water Authority mentions the long history with PPCPs for his agency: Synder was a Ph.D. student when the first synthetic hormones, those found in oral birth control, were found in wastewater streams.
“We made our discovery and published our results in Environmental Science and Technology in 1999, and ever since then, we’ve been pursuing this issue,” says Synder. “We are the principal investigators on about $2 million of external funding on treatment and toxicological relevance in fish studies.”
The most recent report the SNWA has released to the American Water Works Association goes through a whole series of commonly employed treatment processes to study the efficacy of removal of various compounds. Sixty different pharmaceuticals and endocrine disruptors were studied.
The SNWA is moving forward to build ozone technology plants because in addition to being economically viable, ozone is a strong oxidant, and for greater than 90% of PPCPs it can lower them to less than detection with a dose that’s relatively small, all of that simultaneous with disinfection.
“It’s certainly more expensive than chlorine or low energy UV; but when you make that cost comparison, and if you need strong oxidation, there are really only two choices in the industry: high energy UV or ozone,” says Snyder. “The ozone technology looks to be, from our point of view, more robust and cost-efficient. In at least one of our wastewater plants, we will be implementing this system as a demonstration, at 40 million gallons per day.”
Ozone is mixed with up to 90% oxygen and is then bubbled through the water in diffusers. The vast majority of the PPCPs are broken down into smaller compounds with this method.
“There are a few that no oxidants will take care of. These tend to be substances such as flame-retardants, (reflecting the function of this substance),” says Snyder. “In a perfect world you would then run the stream through a carbon filter for a final absorption and polishing.”
Primary companies supplying high energy oxidative ozone and UV systems, according to Snyder, are Ozonia, Wedeco and Trojan, a Canadian producer of high-end UV light systems.
“There is really no silver bullet in removing PPCPs,” says Snyder. “And despite the fact that byproducts may form from their breakdown, they are still no longer biologically reactive. They’ve been broken down into smaller molecules. So far, there is nothing out there that’s perfect.
“RO is impractical for us because of both the wastestream of chemical-laden brine and the water loss, even when there is a 90% recovery of water. The 10% loss of water in a desert is unacceptable."
Pete Hildebrandt is a writer specializing in science and engineering topics.
OW - January/February 2007 |
