Science from the Tap

Mask mandates, social distancing, and frequent hand washing became the norm during the COVID-19 pandemic. While these measures were directed at SARS-CoV-2, public health officials noticed that there were corresponding reductions in other respiratory viruses, such as influenza. But what impact, if any, did these measures have on the spread of enteric pathogens--the ones most commonly associated wit...

The steady climb of a roller coaster generally leads to an exciting, stomach-turning descent. But in the world of drinking water, peaks can be stomach-turning in a much different way. To mitigate these scenarios, potable reuse systems that turn wastewater back into drinking water are often designed assuming worst-case scenarios (e.g., peak pathogen concentrations). While this is a conservative app...

There is always a baseline level of uncertainty when it comes to making critical decisions. But what do you do when there's a significant 'shock' to the system that causes this baseline uncertainty to spike? In 2020, when the genetic signal of SARS-CoV-2 was detected in wastewater, the field of wastewater-based epidemiology (WBE) was jumpstarted. But this also raised questions of whether this emer...

Engineers don't always drive trains, and trains don't always ride on tracks. For decades, civil and environmental engineers have been designing potable reuse treatment trains to ensure that communities throughout the world have safe and reliable drinking water supplies, even in water-scarce regions. All of these treatment trains successfully convert wastewater into purified drinking water, but the...

What do you think of when you hear the word "ozone"? Maybe the hole in the ozone layer? Or the harmful lung irritant present in smog? In describing ozone, the American Lung Association uses the phrase "ozone is good up high, bad nearby". But what if I told you that ozone can also be good nearby? This episode takes a "deep dive" into the use of ozonation for drinking water and wastewater treatment....

Bacteria often get a bad rap, although justified in the case of something like Legionella or E. coli O157:H7. But they're not all bad! In fact, bacteria are the workhorses of wastewater treatment, specifically secondary biological treatment with "activated sludge". Untreated wastewater is loaded with organic matter and nutrients that, if not removed, would result in severe ecological consequences...

Many people fear their next trip to the dentist. Best case scenario you might slip through with just an uncomfortable cleaning, but you could also wind up diagnosed with a cavity, or maybe even needing a root canal. But what if I told you that your biggest concern should be Legionella? This episode takes a "deep dive" into this emerging water-related pathogen and its connection to dental offices....

Whether you own or rent, cost of living just keeps rising. What if I told you that roommates would not only reduce your cost of living but could also reduce your risk of infection by Legionella? Sounds crazy, right? And if you found someone who loves to take frequent and/or long showers, you could reduce your risk even further...your water bill would be a different story though. This episode takes...

Legionella is currently the leading cause of drinking water disease outbreaks in the United States. U.S. drinking water regulations are generally based on an acceptable annual risk of infection of 1 in 10,000 people. Confirmed Legionella infections are still slightly below this benchmark, but some estimates put the true infection burden--accounting for both confirmed and undiagnosed cases--at 2 to...

There are now countless examples of how wastewater surveillance can be used to track trends in infectious disease transmission within a community. Most of these examples focus on established pathogens that have become endemic within those communities, including SARS-CoV-2 (the virus that causes COVID-19). But can these same wastewater methods help detect the introduction of a pathogen into a commu...

The COVID-19 pandemic changed the world as we know it, and we're slowly recovering from its aftermath. But what if viruses aren't the biggest threat to humans? The opening scene from HBO's "The Last of Us" foreshadows a pathogen-driven apocalypse, but not due to a virus. Instead, this one is caused by a fungus. This episode takes a "deep dive" into the use of wastewater surveillance to monitor the...

Have you ever bought furniture with stain-resistant fabrics? Or eaten food that was in a fast-food wrapper or cooked in a nonstick frying pan? If the answer is yes, then you may have been exposed to per- and polyfluoroalkyl substances (PFAS), at least in the past. These "forever chemicals" were highlighted in Mark Ruffalo's recent movie "Dark Waters", and the United States Environmental Protection...

The severity of a pathogen is often described in terms of a case fatality rate, or the ratio of people who die from the infection and associated disease vs. the total number of confirmed cases. Generally, the numerator (the number of deaths) is relatively easy to determine, but the true denominator can be elusive, as many infections go undetected or unreported. If infection by a pathogen leads to...

In March 2020, the lights went out, and the Las Vegas Strip became a ghost town. More than a year later, tourists finally returned to the resorts, casinos, and night clubs as COVID restrictions were lifted and life slowly returned to normal. COVID had different plans, though, as the Delta wave arrived in summer of 2021 before it was rapidly displaced by Omicron leading into 2022. This episode take...

Las Vegas is in the Mojave Desert--one of the driest places on the planet. Receiving about 4 inches of rain per year, some people question whether it makes sense to sustain a city whose water supply seems so uncertain. But surprisingly, Las Vegas is a model city when it comes to water conservation and is also one of the most efficient cities in converting its limited water resources into economic...

On February 7th, 2010, Drew Brees and the New Orleans Saints defeated Peyton Manning and the Indianapolis Colts 31-17 in Super Bowl XLIV. The game was played in Miami--more than 2,500 miles away from the Las Vegas Strip. So how did this game affect wastewater in Las Vegas? This episode takes a "deep dive" into the effects of a special event--in this case, Super Bowl Sunday--on wastewater flow rate...

Unsheltered homeless individuals represent a highly vulnerable population, particularly when it comes to infectious and chronic disease. This is obviously due to the lack of shelter but also because of challenges in seeking and receiving adequate healthcare services. Also, unsheltered individuals are often missed when it comes to traditional public health surveillance. Wastewater surveillance has...

Are the implications of unsheltered homelessness confined to this vulnerable population, or is it a wider problem that affects the broader community? This episode takes a "deep dive" into the nexus of public health, environmental health, and unsheltered homelessness in Las Vegas. Specifically, this episode highlights the environmental "fingerprint" of unsheltered homelessness and the potential eff...

Despite being described by some as "toilet to tap", indirect (IPR) and direct potable reuse (DPR) systems are capable of producing some of the highest quality drinking water on the planet. These systems involve advanced treatment of recycled water (wastewater) to augment conventional drinking water supplies, particularly in areas suffering from water scarcity or water quality impairment. But does...

Is the opioid epidemic worsening? Is fentanyl continuing to pour into the community, or is the supply drying up? And how do special events like the Super Bowl and March Madness affect drug consumption in Las Vegas? This episode takes a "deep dive" into how wastewater surveillance was used to assess illicit drug consumption in Las Vegas. This emerging public health tool can help identify high risk...

Ever wonder how we determine the level of treatment needed to ensure drinking water is safe? What if we're starting with raw sewage? This episode takes a "deep dive" into indirect (IPR) and direct potable reuse (DPR)--essentially turning wastewater back into drinking water. This episode describes how treatment targets are established and how the approach differs throughout the United States. Speci...