Analyzing Drug Use Spatially
To test the possibility of using wastewater to analyze the spatial distribution of certain drugs, researchers from three universities contacted 130 municipal WWTPs throughout Oregon. Ultimately, 96 facilities of varying size voluntarily agreed to participate. Representing 65% of the state’s population, the WWTPs collected 24-hour composite samples of their influent on the same day, Tuesday, March 4, 2008.
Using large-volume injection, followed by liquid chromatography–tandem mass spectrometry, the researchers tested the samples for the presence of three drug indicators: benzoylecgonine (BZE), the major metabolite of cocaine; methamphetamine; and 3,4-methylenedioxymethamphetamine (MDMA), commonly known as “ecstasy.” Cocaine and methamphetamine were selected for analysis because they are “two of the primary drugs when it comes to impacts on human health,” said Jennifer Field, a professor of environmental and molecular toxicology at Oregon State University (Corvallis) and a member of the research team. Although MDMA is also of concern, it was selected mainly for comparative purposes, she said.
After determining the concentrations of each of the drugs in the samples, the researchers calculated “index loads” by multiplying the drug concentrations, in nanograms per liter, by a facility’s total wastewater flow, in liters, and dividing by the population served by the facility. Drugs that were detected at concentrations below a certain limit were labeled as “below the level of quantification,” while drugs found in concentrations below the analytical detection limits were labeled “no detect.” To enable spatial analysis of the results, the researchers designated the participating municipalities as “urban,” “large rural city/town,” and “small rural town,” based on classifications developed by the U.S. Census Bureau.
In this way, the researchers were able to “tease out” differences between the spatial distributions of the usage of the three drugs, Field said. For example, BZE occurred in measurable amounts in 80% of the samples, though index loads for the cocaine metabolite were found to be much higher in urban areas. By contrast, methamphetamine was present at measurable levels in the samples from all municipalities. MDMA was present in quantifiable levels in less than half of the samples, though index loads tended to be higher in more urban areas. Results of the study appear in the September issue of the journal Addiction.
Validating the Process
The findings were “generally along the lines of what I anticipated,” said Caleb Banta–Green, a research scientist at the Alcohol and Drug Abuse Institute at the University of Washington (Seattle) and another member of the research team. In a sense, the findings were good news for the researchers, because the main focus of the study was to validate the ability of the sampling and analytical process to discern known drug trends. The researchers were gratified to see that the process did in fact “reflect reality,” Banta–Green said.
Another goal was to determine the extent to which WWTPs would agree to participate in a study of this sort. “There was a very high level of interest,” Field said. “Our hats are off to the wastewater treatment facilities and the municipalities they represent for participating.”
Oregon’s WWTPs were eager to assist the researchers, said Janet Gillaspie, executive director of the Oregon Association of Clean Water Agencies (Portland). “Our members were very happy to help out in applying a new scientific tool to a very different type of problem than we traditionally deal with,” she said. “If sampling influent and analyzing it can help target and improve addiction treatment services in communities, we’re happy to help.”
The fact that the study was designed to take advantage of sampling already performed by most WWTPs likely helped boost participation. For the City of Salem, the decision to participate was an easy one, said Stephanie Eisner, acting wastewater treatment plant division manager for the city. “It wasn’t any cost to us, and it really didn’t take much time,” she said. “We felt like if the information could help the study, and it was something that simple for us to do, we would participate.”
Overcoming Local Data Limitations
The City of Ontario reached a similar decision. Contributing to the study “sounded like a worthy thing,” said Art Allen, water–wastewater treatment supervisor for the city. Moreover, sampling influent seemed the “least intrusive way” to determine patterns of drug usage at the community level, he said. Geography also helped convince representatives of the Ontario WWTP to participate. Located near the border with Idaho, Ontario is one of the larger municipalities in Oregon’s less populous eastern half. “There’s just not that many people in eastern Oregon,” Allen said. Therefore, “we thought [Ontario’s sample] might be some very useful information” for the researchers, he said.
For many of the small municipalities participating in the study, the data gleaned from the influent sample is the first attempt to identify local drug use patterns at the community level. “Most of the cities in Oregon have no local data on drug use,” Banta–Green said. “Now we have these much smaller cities that actually have their own local data,” he said, identifying this result as one of the “more exciting” of the study.
The method for sampling and analysis developed by the researchers is intended to identify trends regarding drug use communitywide, not to target individuals for law enforcement activity. “This approach is aimed at the scale of full communities for making decisions about drug use and patterns within a whole community,” Field said. Although other methodologies are used to compile data regarding drug activity, few such approaches assess drug use at a community level, she said. Consequently, the results of the influent sampling are “filling a data gap” in drug epidemiology, she said.
Addressing the Limitations
As useful as the influent data may be in understanding drug use, the researchers readily acknowledged that the information has certain limitations. For example, the results pertain to a single day at those WWTPs that voluntarily elected to participate. “It’s not a random sample,” Field said. Therefore, the findings do not present a complete measure of drug excretion for any of the participating communities or the entire state of Oregon.
How collection systems affect drug levels in wastewater is another critical question. Such factors as differing residence times, microbial activity, and pump stations introduce “sources of variability,” Field said. “More work has to be done,” she said, to learn how to account for this variability.
Other questions to be addressed include how often to sample to ensure that the results represent actual conditions. For example, if a municipality wants to analyze its wastewater for the presence of drugs, Field said, no one knows how often to sample or how much data is needed to provide accurate results. “Is one sample enough?” she asked. “Do you need [to sample] monthly? Quarterly? Yearly? We’re trying to figure that out.”
To this end, Field and Banta–Green are conducting a yearlong study in which 20 WWTPs — 10 in Oregon and 10 in Washington state — are collecting influent samples on a randomized weekly basis. Begun this past January, the study is designed in part to determine how much data is needed to enable accurate comparisons of drug levels in wastewater on an annual basis. “If I want to compare 2008 to 2009 and 2010, that means I need to do sampling over multiple years,” Banta–Green said. “How many samples do I need to collect? Do I need to account for seasonality or day of the week?”
The ability of the researchers to answer these and similar questions will go a long way toward determining if more WWTPs participate in drug-use studies in the future, said Guy Allen, an operator at the City of Corvallis Water Reclamation Plant, which participated in the March 2008 sampling effort. “How useful [the sampling] is in the long run will be a determinant as to how widespread it is in the future,” he said
Envisioning Other Uses
Although questions remain regarding how best to gauge the presence of drugs in municipal wastewater, the technique shows promise as a means for addressing a variety of questions in the future. “I think [the testing] is a great opportunity,” Field said. In addition to efforts to evaluate patterns regarding drug use within communities, the approach also could be used to evaluate the effectiveness of efforts to reduce the amounts of legal pharmaceutical drugs that find their way to WWTPs. “There’s a lot of interest in pharmaceutical ‘take-back’ programs and reducing the burden of pharmaceuticals that flow to and through wastewater treatment plants,” Field said. Sampling influent for such compounds offers a “portal through which we can better understand if the loads coming to treatment plants have been reduced due to education or intervention,” she said.
— Jay Landers,
Mandatory rainwater harvesting ordinances are on the rise in the U.S. Southwest
As drought and water scarcity have intensified in many regions across the United States, municipalities are increasingly putting more value on water conservation measures, such as rainwater harvesting and other technologies that promote water catchment, water retention, and groundwater recharge. For years, rainwater harvesting has been practiced voluntarily by builders, developers, and residents alike in many U.S. cities, especially in areas experiencing acute long-term water shortage. However, some Southwest municipalities are beginning to take a more aggressive approach.
In Tucson, which receives only 28 cm (11 in.) of rain per year, the City Council recently approved an ordinance requiring all new commercial development to supply 50% of the water needed for landscaping from harvested rainwater. Along with this ordinance, which will take effect in June 2010, the City Council also passed a new rule requiring graywater plumbing hookups on all new residential homes for diverting wastewater from showers, bathtubs, washing machines, and nonkitchen sinks for outdoor irrigation.
The rainwater harvesting initiative was spearheaded by Rodney Glassman, a first-term councilman with a Ph.D. in arid land resource sciences. “In Tucson, rainwater harvesting has always been the exception rather than the rule,” Glassman said. “We made a commitment to change that. With very limited water resources, it’s important to promote more water conservation as a means for preserving our groundwater and potable supplies.”
To establish support for a new rainwater harvesting law, Glassman formed a diverse stakeholder group of builders, developers, landscape architects, and environmental groups. The purpose was to bring together all parties that had an interest in the proposed ordinance, Glassman said, in order to work out an effective and fair rule with a realistic implementation date.
“Everyone involved was provided with an equal seat at the table and an equal voice,” Glassman said. “This promoted a very collaborative approach and allowed for the greatest chance of success.” Glassman’s strategy proved useful, as the measure was passed unanimously by the City Council.
The policy focuses on commercial properties because of their considerable water-saving potential. “About 40% of the potable water used in new commercial development goes toward landscaping,” Glassman said. “The new ordinance effectively cuts that usage by 50%.”
Following approval, a group comprising more than 20 members was assembled to write the technical standards. “The ordinance places a great amount of flexibility in the hands of the developer,” Glassman said. “The requirements must be met, but whether active or passive rainwater harvesting techniques are installed is up to the individual project designer. These techniques can range from large-scale underground tanks to simply designing curb cutouts in the parking lot at the time of construction.”
The ordinance includes language expressing Tucson’s intention to maintain its leadership role among desert cities as an innovator in water resource management and water use efficiency.
“Tucson takes a very progressive approach toward water conservation and closely monitors all state and federal regulations that deal with water resources,” said Jeff Biggs, director of the Tucson Water Department. “The city is also very concerned with the quantity and quality of its water resources, such as the Colorado River, and how climate change can potentially affect the water industry over the next decade.”
Since Tucson’s precipitation and aquifer levels are considerably below average, Biggs said, it is prudent for the city to advance water conservation initiatives that reduce groundwater pumping, as well as the city’s reliance on water obtained from the Central Arizona Project. “Water conservation efforts have shown to be effective in Tucson,” he said. “Over the last decade, as a result of voluntary water harvesting and other practices, annual residential usage in terms of gallons per person has dropped by 28%.”
To comply with the new ordinance, developers of commercial projects will be required to submit a rainwater harvesting plan that is subject to a design review. The plan also must include a landscape water budget. “This requires developers to calculate the amount of water that can be captured, based on the proposed rainwater harvesting design,” Biggs said. “The type of plants and the intended coverage also need to be included, which help determine how much water will be needed to support the landscaping.”
In addition, Tucson is planning to implement a pilot program that will test different rainwater harvesting technologies. “The goal with the pilot is to determine which kinds of techniques and controllers are the most effective,” Biggs said. “This will ultimately help customers choose the right designs and maximize the amount of water they can capture.”
A commercial rainwater harvesting ordinance also has been proposed by the Town of Oro Valley, immediately north of Tucson, which is considering several changes to its landscape code to achieve more water savings.
Santa Fe, N.M.
Under the 2003 Santa Fe County ordinance, commercial development is required to collect all roof drainage into cisterns to be reused for landscape irrigation. For residential development, the mandate is slightly less, with properties required to collect rainwater from a minimum of 85% of roof areas for reuse in landscape irrigation. Residences with more than 230 m2 (2500 ft2) of heated area must submit a roof drainage plan, and cisterns are required to be buried, partially buried, or fully enclosed with an insulated structure. Residences with less than 230 m2 (2500 ft2) of heated area must have a rainwater catchment plan showing the use of rain barrels, cisterns, or other catchment basins.
According to Jan Daniels, development review specialist with the Santa Fe County Land Use Department, the county also encourages passive rainwater harvesting designs, such as berms and other techniques that can direct drainage to landscaped areas. “As long as the plan is shown to be effective for harvesting rainwater and conforms to the ordinance, builders and developers have freedom in their designs,” Daniels said.
Efforts are being made within the Santa Fe County Land Use, Planning, and Legal departments to address sustainability, and water conservation will be a key component as it relates to green infrastructure, said Laurie Trevizo, water resource specialist with the Land Use Department. The county is now “writing a comprehensive Water Conservation Plan with the intention of developing a more encompassing strategy that encourages different types of water harvesting techniques,” Trevizo said. “We are looking at the plans Tucson has published and want to develop a more holistic approach to water conservation that takes into account the bigger picture.”
For providing guidance in developing the plan, Trevizo, who is also manager of the Water Conservation Program, has organized a steering committee of local water conservation experts, including rainwater harvesting designers, landscape architects, hydrologists, and community planners. The new plan will be ready for public review in January and will continue to encourage creativity, Trevizo said, along with more-quantitative measures, such as checklists and formulas for calculating water balances.
Although there is a considerable amount of momentum behind employing rainwater harvesting policy, several cities and states remain a long way out from adopting — or probably even considering — some kind of regulation. Colorado, for example, only recently passed legislation making rainwater harvesting legal, in some cases. Previously, under the state’s old rainwater harvesting laws, rain falling to the ground was deemed the property of water-rights holders. Collecting that rain, therefore, was considered stealing. The new legislation allows residents on wells to collect rainwater on surfaces up to 280 m2 (3000 ft2) in area. A second piece of legislation approved 10 pilot rainwater collection projects for new housing or mixed-use developments.
A similar situation is unfolding in neighboring Utah, where rainwater harvesting is still illegal, as precipitation falling to the ground is considered state property. However, pending legislation (SB 128) could change this law by allowing residents to collect and store up to 9500 L (2500 gal) of rainwater.
According to Trevizo, some cities outside the Southwest region are considering adopting similar ordinances. She, along with Santa Fe County Commissioner Kathy Holian, recently was asked to present the policies associated with the county’s rainwater harvesting ordinance at the American Rainwater Catchment Systems Association (Austin, Texas) national conference in Atlanta. “Due to drought in other regions, municipalities that did not plan accordingly are now seriously considering adopting some type of rainwater harvesting regulation,” Trevizo said. “As water conservation becomes a bigger necessity, it will be interesting to see the different policy approaches toward rainwater harvesting.”
— Jeff Gunderson, WE&T