Having a safe, resilient water supply is a luxury that, even in 2018, we cannot always count on. Issues ranging from water scarcity to compromised water quality continue to ravage the globe, recently hitting hard here in the United States. In early 2016, a state of emergency was declared in Flint, Michigan after lead levels in the local drinking water were deemed unsafe. The city switched to Flint River water in early 2014 as their water source, but the new supply caused lead to leach out of the aging water pipes and into the water itself. Despite citizen health complaints and independent agency warnings, it took over two years for governmental action. The Flint community was forced to use bottled water for cooking, drinking, and bathing but long-term health ramifications had already taken hold from heightened lead exposure. In September of 2017, Hurricane Harvey ravaged the Texas Gulf Coast. Many water and wastewater plants were flooded and damaged in the event causing compromised water drinking quality in many areas as well as fecal matter and harmful bacteria in the flood waters. In both these cases, giving the public the tools and knowledge to test and provide data on their home, work, or school water quality would have provided quick data to the local governments or plant operators allowing for a better understanding of the extent of the water quality problem.
This project, a collaboration between The University of Texas at Austin and The University of San Francisco de Quito (USFQ, Ecuador), was carried out in the Fall 2017 with the objective of engaging the community scientists (students in the undergraduate Introduction to Environmental Engineering course at UT, and students in the undergraduate "Environmental Engineering Fundamentals" at the USFQ) in a study to know the quality of their drinking water. A total of 100 students were introduced to the environmental, economic, and technical problems involved in the treatment, the distribution, and the quality measurement of drinking water.
Prior to initiating the project, students were given an anonymous pre-survey to establish their previous knowledge in the matter. The survey consisted of 11 total questions assessing the students’ knowledge about water quality and supply locally in Austin and Quito, water quality monitoring, and sample collection and analytical techniques.
When developing the project, it was important to take into consideration the interests of the collective students, to keep them engaged and interested throughout. Divided into groups, each group submitted a half-page abstract, designing an experiment detailing which water source they would test, why, and which parameters they would test for. Overall, the students tended to be interested in water sources they utilized in everyday life, such as campus drinking fountains, showers, or kitchen faucets. Taking their ideas and interests into consideration, a simple, yet hands-on and informative, experiment was developed to allow the students to test the water sources they were interested in. In Austin, half of the groups would be testing their kitchen faucets and half would be testing drinking fountains on campus. In Quito, half of the groups would be testing regular tap water (a small % of the population consider it safe to drink even though the quality is not bad), and half would be testing the newly installed drinking water fountains in campus (with a biological filtration system).
The overarching goal of the project was to compare water quality in samples taken immediately after opening the tap (first flush samples) to that in samples taken after running the tap for five minutes (purged samples). The following hypotheses were presented to the students to help guide their initial thinking:
1) Drinking water sources that are more frequently purged will have better water quality parameters than those that remain stagnant for longer periods of time (Quito and UT).
2) Water quality can be linked to the type of piping and where it is at in the distribution system (UT).
3) Chlorine residual present in the drinking water will be dependent on where it is located within the distribution system (less residual towards the end of the system; UT).
4) Newly installed fountains with filters will have better water quality than regular tap water (Quito).
A standardized procedure was developed to guide the students through each sampling activity and sampling kits were prepared and distributed. Each group took two total samples, the first flush sample (after the water system has not been used for approximately 12 hours) and the purged sample (after running the water for five minutes continuously). Each group was given a SureCheck Safety Test kit which allowed them to quickly and easily test the pH, total chlorine, and free chlorine of their samples.
An optional activity was also presented to the students allowing them to test for additional water quality parameters. Each group who participated was given a First Alert Drinking Water Test Kit, a home test kit that tests for additional parameters such as total nitrate, hardness, bacteria, lead and pesticides. This test kit is designed to quickly and easily test the quality of a potentially compromised drinking water supply. The goal of this optional activity was to have the participating groups evaluate their overall experience with using the kit and to suggest any improvements, keeping in mind the applicability of this kit to areas compromised by natural disasters. It is important to highlight that for research purposes, any positive given by this test would need to be double-checked in the lab. For example, the occurence of not pathogenic bacteria in water distribution systems is normal, and this kit would not differentiate if the positive result comes from pathogenic bacteria or from naturally occuring bacteria.
After sampling and in-situ analysis was complete, students brought their samples into the lab to run some additional analysis. Guided by experienced UT senior researchers and graduate students, each group ran an IDEXX Heterotrophic Plate Count (HPC) test as well as tested the conductivity and pH on a handheld meter. This component exposed the students to effective lab techniques as well as introducing them to simple lab safety and sanitation practices. Data from each groups’ in-situ and lab analyses was collected and distributed to the whole class for further analysis and interpretation.
Students at the USFQ testing their water samples
And the results are in! For both the water fountain and apartment tap samples, pH was around 9.3, not surprising for the Austin area. However, all these pH values were out of range for the SureCheck kit to read which tells us that these kits may not always be appropriate for testing the pH of drinking water. However, in Quito, the pH was ~6.5, and the kit measured 7.5 in average. Overall, the HPC values were higher for the first flush samples compared with the post-five-minute flush samples, suggesting that many sink and fountain piping appurtenances may have some degree of biofilm build-up and/or microorganism regrowth. The HPC values were much higher for the apartment samples compared to the water fountain samples, which was surprising given that many of the apartment tap samples were taken from newer apartments buildings. This may be attributed to frequency of use. The campus drinking fountains are likely used often throughout the day, while the apartment kitchen taps may only get used sporadically in the morning and evenings. Overall, all HPC values are well beneath the EPA maximum of 50,000 MPN/100 mL. The total and free chlorine values fell within the respective range set by the EPA and CDC. The EPA recommends a maximum of free and total chlorine of 4 mg/L to avoid negative taste or odor impacts and has no minimum standard. TCEQ recommends a minimum of 0.2 mg/L of free and 0.5 mg/L total chlorine for effective treatment. In Quito, two of the 6 groups reported positive values for biological growth (given by the First Alert Drinking Water Test, which does not indicate the bacteria detected were bad for humans). Chlorine levels in regular tap water were between 0.25 and 1.5 mg/L, within the recommended values. In the water fountains though, the levels were under 0.25 mg/l, not surprising given that the filtration system also captures the chlorine residual.
To finish out the project, students from UT were tasked with developing a written water quality assessment. Questions and hypotheses were previously provided to guide their thinking. Each group also developed a comprehensive infographic. The goal of the infographic is to convey the results of the water parameter testing in a format that can be easily understood by the public. Check out some of our talented students’ infographics (Fig. 1 and Fig. 2).
Figure 1. Infographic prepared by Juan R., Albert C., Zia L., Abby B., Jennifer R., Ashley B., Kresentia S., and Klarissa L., adapted by Rasmus and Maestre.
Figure 2. Infographic prepared by Sasha K., Wesley S., Jopert, Brice K., Syed A., Daniel D., and Pierre F., adapted by Rasmus and Maestre.
Throughout this project students learned invaluable techniques on how to assess water quality not only in a laboratory setting but with tools and kits available to the public as well. Many of these kits and testing methods are available at very low costs and distributing these to the public in affected areas would serve to provide a high volume of data in a short amount of time. Similarly, to the infographics created by the students, it is important to distribute information to a general audience that is easy to understand. Increased public awareness and involvement will make for better citizen scientists and a safer drinking water supply!
Thanks to Drs. Kerry Kinney and Navid Saleh for their support with the experiment design. Thanks to Stetson Rowles for helping with the lab analysis. Special thanks to Dr. JP Maestre for his guidance, and for providing invaluable input, support with the experimental design, and coordination and help from start to finish. Thanks to Melanie Valencia (USFQ) for her interest and collaboration in this project.
Information on the EPA Drinking Water Regulations can be found here.
Information on the TCEQ Drinking Water Regulations can be found here.
by Madison Rasmus, M.S. Candidate, Environmental and Water Resources Engineering.
Since E. coli (which should always be italicized, although formatting limitations prevent me from italicizing this genus and species in this post's title!) has such a big scary reputation in the popular press, it’s important to remember why we measure E. coli, and know how the Texas Commission on Environmental Quality (TCEQ) regulates E. coli in public waters. As it turns out, neither why we measure E. coli nor how we regulate it is totally straightforward.
First, E. coli is a species of bacteria. It is a species that includes many sub-species, some of which are human pathogens (most commonly associated with food poisoning in the US) and many of which aren’t. E. coli are relatively easy to measure, live in the guts of mammals and birds, and have some other nice characteristics that make them useful as a proxy for mammalian or avian fecal contamination. But that’s it! We use them as a proxy for other pathogenic organisms potentially transmitted via feces in water, and not so much because we are worried about the E. coli themselves. Recent debates in Rio de Janeiro over microbiological water quality for Olympic events highlight the importance of this point and the potential implications of building regulations on indicator organisms and not specific human pathogens (see http://bigstory.ap.org/article/d92f6af5121f49d982601a657d745e95/ap-investigation-rios-olympic-water-rife-sewage-virus). E. coli is not a perfect indicator of fecal contamination, and finding better (and still practical!) indicators is an active area of research. If you’re interested, Google “microbial source tracking”.
Second, the TCEQ regulates E. coli levels by setting a mean value over time that a water body must not exceed (the mean must be computed from at least 10 samples over two years), as well as a maximum single sample value that should never be exceeded. This is pretty standard, since the EPA recommends this. But it means that after a single sampling event such as ours, it is possible to say that a water body is violating the standard, but it is impossible to say that a water body is compliant. Also, you have to follow specific sampling and analysis protocols in order for your E. coli measurements to be truly comparable with the standards. (We did not follow this protocol.) This promotes quality control and also eliminates potential differences produced by different methodologies, even if they are both done correctly!
Another important caveat with regard to comparing our E. coli measurements with the TCEQ standards is that we used a technique which gives us units of MPN/100 ml, while the standard is specified in CFU/100 ml. MPN is “most probable number” of viable E. coli, and CFU is “colony forming units”, a proxy for individual viable E. coli. A recent paper1 found that regardless of how careful you are in executing your lab analyses, MPN values will tend to be higher and show greater variability than CFU measurements. These differences are produced by the statistical assumptions built into MPN estimates, not just lab procedure variability, so they will always be there!
1. Gronewold AD1, Wolpert RL. 2008. Modeling the relationship between most probable number (MPN) and colony-forming unit (CFU) estimates of fecal coliform concentration. Water Res. 2008 Jul;42(13):3327-34.
As part of the UTBiome’s effort to paint a picture (with data, of course!) of Waller Creek running through campus, we carried out another sampling event this past February. This time, the graduate engineering microbiology class collected environmental and microbiological data from three spots near the Civil, Architectural, and Environmental Engineering building (called ECJ) at San Jacinto and Dean Keeton. Here’s a map below:
Figure 1. The balloon icons indicate where we sampled along the Creek. Even though it doesn’t looks like there’s water running through the top balloon icon, there is! Water flows from top to bottom.
We were particularly interested in looking at potential water quality impacts produced by the construction site within a dozen yards of the Creek. With the construction of a new engineering building (the yellow box on the map), large trucks are stationed near the Creek, where they are periodically rinsed down. We thought we might see an imprint from this truck washing show up in the Creek.
So we selected water quality parameters that might be directly impacted by rinse water, such as total suspended solids, turbidity, conductivity, and a few others. We also examined concentrations of fecal indicator bacteria, since Waller Creek has a history of violating the City of Austin’s bacterial standards. All of these we measured at three spots along the creek: two upstream (one in the western tributary leg, one in the eastern) and one downstream, just after the confluence of the two legs. The construction site lay between our upstream and downstream sites on the western leg.
And our results are in! We found good news with regard to the construction site’s impact, and some “not-so-news” with regard to the Creek’s fecal indicator bacteria levels.
From a physicochemical standpoint, the segment of Waller Creek running adjacent to ECJ appears to be in fine shape for an urban watershed stream, both historically and with the current sample values from this lab. Out of our measurements, conductivity was the only parameter that appeared higher than average, and was consistently high across all our samples. This means we cannot attribute the high conductivity to dissolved solids produced by the truck washing at the construction site, which would have generated conductivity levels downstream. One explanation may be lower flow values across the watershed, due to general drought conditions, which could concentrate ions in solution, thereby elevating conductivity. Flow measurements or examining the recent precipitation record at subsequent sampling events may help elucidate discrepancies such as these and others in water quality measurements.
At a minimum, we expected to see elevated turbidity and TSS levels after the sandy construction zone. However, the impacts of construction at the time of sampling were either negligible or not differentiable from impacts produced by mixing with the eastern fork. In addition to the TSS and turbidity data, none of the other physicochemical parameters vary greatly before and after the construction zone. It is possible, since we do not know the time of the most recent rinsing event, that little runoff had been generated prior to our sampling. Thus, it is important to remember that it is still possible that the construction site impacts Waller Creek; our data merely suggests that none of the parameters we measured were impacted that morning.
The not-so-news suggested by our data is that Waller Creek (next to campus) may still support levels of E. coli higher than those allowed by the Texas Commission on Environmental Quality (TCEQ). In two of our six samples (see Table 1), E. coli concentrations of 410 MPN/100 ml exceeded the maximum allowable level for any single sample, which is 399 CFU/100 ml. Note that there is some fudge factor thrown in here, as our units of MPN do not match the standard’s units of CFU. See the Technical Note post for more on this, as well as some background on why we care about E. coli.
Table 1. Waller Creek E. coli levels near ECJ
As I’ve hinted, TCEQ is well aware of Waller Creek’s elevated bacterial levels. In fact, they recently developed a total maximum daily load (TMDL) plan with five management measures aimed at reducing fecal inputs into Waller and a few other urban waterbodies. These measures focus on riparian zone restoration, wastewater infrastructure, domestic pet waste, resident outreach, and stormwater treatment strategies. Riparian buffer restoration is expected to reduce fecal pollution by several mechanisms, including seepage into soil, microorganism predation, adsorption to vegetation and soil surfaces, and environmental inactivation (e.g., dehydration or UV denaturation). The wastewater infrastructure focus includes installing more public toilets and creating incentives for onsite sewerage repair and improvements. The 1429C_02 segment of the Waller Creek watershed (part of which runs next to campus) has a sizeable pet population (greater than 5,000 cats and about 5,000 dogs (TCEQ 2015), so fortifying pet waste infrastructure by making pet waste bags and disposal containers available, along with education outreach on the issue, is expected to make a considerable impact as well.
It is interesting to consider the alternative to reducing Waller Creek’s fecal inputs: downgrade Waller Creek’s regulatory status to “secondary contact”. It would be interesting to gather more observational data on Waller Creek’s true usage patterns, since none of us has ever witnessed swimmers in the Creek near campus. More observation would be needed to determine if people are really swimming in the Creek, and thus if the current standard is overly conservative. Even if no one ever observed a swimmer in Waller Creek, however, supporting a waterbody with elevated fecal contamination running through the heart of a major city could run contrary to TCEQ’s mission to “protect our state's public health and natural resources consistent with sustainable economic development”. The risk that people might swim in Waller might just be too high.
Last Saturday a group of people from EWRE-UTBiome participated at the event "Introduce a Girl to Engineering". In spite of the cold weather, more than 6000 girls (probably closer to 8000) came and enjoy all the activities organized in campus. We hosted an activity aimed at explaining what DNA is, what can be used for in engineering, relationships with easily recognizable human features, and actually extracting DNA through a simple process. We also tested participants and their parents regarding sensitivity to PTC, that is aversion to cruciferous vegetables like broccoli, Brussels sprouts...)
It was a very interesting experience. More than 120 young and potentially future 'sciencegineers' participated in our activity. I would say >99% of them showed an incredible interest and enthusiasm. They loved the fact they could take home the DNA they extracted in a tube on a necklace/wristband. Understanding the connection between DNA, proteins and phenotype was also a highlight! Some of them understood why they did not like broccoli (at least at first).
I attach in this post our posters in case they can be of help, and some pics from the event.
Thanks Michal for helping organizing and thanks Runnan, Sarah and Allison (EWRE alumni) for organizing and attending the 6-h long event.
The UTBIOME interactive web mapping platform is the digital face of UT envisioned as a living laboratory. After hours of tiring field sampling, the bulk of the data that makes the map is made available in a raw format that needs another day or two for curation. The raw data is checked for proper units, and the quality of the data is assessed before it is ready for public viewing through the online web mapping platform. A short overview of the data flow process includes data collection, data messaging and finally data publication. Once the raw data is quality checked and ready for public viewing a bunch of intermediate workflows are kicked in. The quality controlled data is converted into CSV and JSON files by using custom python scripts. Most of the collected data is available for download as CSV files through the online web mapping platform. The JSON files help in loading the folder hierarchy that allows the viewers to explore the data in a coherent and consistent manner. A web server and ArcGIS map server is used to host files and publish map services. By using the ArcGIS JS (javascript) web API, a custom map interface is built that puts all the things together.
The UTBIOME platform provides us with a unique opportunity to integrate a variety of environmental, energy and sustainability practices in a single portal, where people can interact with already populated datasets as well as enrich the data store by submitting their own datasets. The platform is self sustainable, and can be easily replicated by anyone who wants to showcase such a complex environment in a single coherent platform. By making use of the latest web technology, the UTBIOME interactive platform can serve as a starting point for many users who want explore and understand the complex interactions of our urban setting.
Harish Sangireddy.
PhD candidate at The University of Texas at Austin.