For Outdoor Workers, Extreme Heat Poses Extreme Danger

For Outdoor Workers, Extreme Heat Poses Extreme Danger

extreme heat and workforce health

May 11, 2022

Extreme Heat
Outdoor Workers
Workforce Health

For Outdoor Workers, Extreme Heat Poses Extreme Danger

Study explores effects of summertime heat waves on workforce health in Las Vegas, Phoenix, and Los Angeles

Working outdoors during periods of extreme heat can cause discomfort, heat stress, or heat illnesses – all growing concerns for people who live and work in Southwestern cities like Las Vegas, where summer temperatures creep higher each year. But, did you know that female outdoor workers are experiencing disproportionate impacts? Or, that more experienced outdoor workers are at higher risk than those with fewer years on the job? 

In a new study in the International Journal of Environmental Science and Technology, scientists from DRI, Nevada State College, and the Guinn Center for Policy Priorities explore the growing threat that extreme heat poses to workforce health in three of the hottest cities in North America – Las Vegas, Los Angeles, and Phoenix. Their study results hold important findings for outdoor workers, their employers, and policymakers across the Southwestern U.S.   

To assess the relationship between extreme heat and nonfatal workplace heat-related illness, the study compared data on occupational injuries and illnesses for the years 2011-2018 with heat index data from Las Vegas, Los Angeles, and Phoenix. Heat index data combines temperature and humidity as a measure of how people feel the heat. 

“We expected to see a correlation between high temperatures and people getting sick – and we found that there was a very clear trend in most cases,” said lead author Erick Bandala, Ph.D., assistant research professor of environmental science at DRI. “Surprisingly, this type of analysis hadn’t been done in the past, and there are some really interesting social implications to what we learned.” 

First, the research team analyzed changes in heat index data for the three cities. They found a significant increase in heat index at two of the three locations (Phoenix and Las Vegas) during the study period, with average heat index values for June-Aug climbing from “extreme caution” in 2012 into the “danger” range by 2018. Over the same period, data from the Bureau of Labor and Statistics showed that the number of nonfatal heat-related workplace injuries and illnesses in each of the three states increased steadily, climbing from below the national average in 2011 to above the national average in 2018.  

heat-related nonfatal workplace injuries

According to new research, the number of heat-related nonfatal workplace injuries in Arizona, California, and Nevada increased between 2011 and 2018. The three states now exceed the U.S. average.

Credit: Erick Bandala/DRI.

“Our data indicate that the increases in heat are happening alongside increases in the number of nonfatal occupational injuries across these three states,” Bandala said. “Every year we are seeing increased heat waves and higher temperatures, and all of the people who work outside in the streets or in gardens or agriculture are exposed to this.”

Next, the study team looked deeper into the data to learn about the number of male and female workers being affected by heat-related workplace injuries. At the beginning of the study in 2011, 26 to 50 percent of the people affected across the three states were female. By 2018, 42 to 86 percent of the people affected were female.

Study authors believe that the reason for this increase may be due to more women entering the outdoor workforce, or it could be related to the vulnerability of women to certain heat-related effects, like hyponatremia — a condition that develops when too much plain water is consumed under high heat conditions and sodium levels in blood get too low.

“As the number of female workers exposed to extreme temperatures increases, there is an increasing need to consider the effect of gender and use different approaches to recommend prevention measures as hormonal factors and cycles that can be exacerbated during exposure to extreme heat,” said study coauthor Kebret Kebede, M.D., associate professor of biology at Nevada State College.

The authors examined other variables, such as the length of an employee’s service with an employer. They found that the number of heat-related injury/illnesses tended to increase as the length of service with the employer increased, and that those with more than five years of service were at greater risk than those with less than one year of service. This may be due to employees with more years of service having a reduced perception of risk, or could be a cumulative effect of years of chronic heat exposure on the well-being of outdoor workers.

heat-related injuries/illnesses

New research shows that in Arizona, Nevada and California, the number of heat-related injuries/illnesses tended to increase as length of service with the employer increased.

Credit: Erick Bandala/DRI.

In severe cases, heat-related illness or injury can cause extensive damage to all tissues and organs, disrupting the central nervous system, blood-clotting mechanisms, and liver and kidney functions. In these cases, lengthy recoveries are required. The authors found concerning evidence that heat-related injuries are keeping many outdoor workers away from work for more than 30 days.

“These lengthy recovery times are a significant problem for workers and their families, many of whom are living day-to-day,” Bandala said. “When we have these extreme heat conditions coming every year and a lot of people working outside, we need to know what are the consequences of these problems, and we need the people to know about the risk so that they take proper precautions.”

heat-related injuries

Authors of a new study on the impacts of extreme heat on workplace health found concerning evidence that heat-related injuries are keeping many outdoor workers away from work for more than 30 days.

Credit: Erick Bandala/DRI.

The study also explored connections between heat-related injuries/illnesses and the number of hours worked, the time of day that the event occurred, and the ethnicities and age groups that were most impacted.

Study authors hope that their results will be useful to policymakers to protect outdoor workers. They also hope that the information will be useful to outdoor workers who need to stay safe during times of extreme heat, and employers who rely on a healthy workforce to keep their businesses operating.

“This study underscores the importance of and the need for the work the Nevada Occupational Safety and Health Administration (OSHA) is doing to adopt a regulation to address heat illness,” stated Nancy Brune, Ph.D., study co-author and senior fellow at the Guinn Center.

“As temperatures continue to rise and heat-related illnesses and deaths continue to rise, the need for public policies to alleviate health and economic impacts is growing,” Bandala said.  “I hope to continue doing research on this problem so that we can have a better of understanding of the impacts of extreme heat and how to help the people who are most vulnerable.”

More information:

The full study, “Assessing the effect of extreme heat on workforce health in the southwestern USA,” is available from the International Journal of Environmental Science and Technology:

This project was funded by NOAA/IRAP (Grant no. NA18AR4310341) and the National Institute of General Medical Sciences (GM103440) from the National Institutes of Health. Study authors included Erick Bandala (DRI), Nancy Brune (Guinn Center for Policy Priorities), and Kebret Kebede (Nevada State College).


About DRI

The Desert Research Institute (DRI) is a recognized world leader in basic and applied environmental research. Committed to scientific excellence and integrity, DRI faculty, students who work alongside them, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge on topics ranging from humans’ impact on the environment to the environment’s impact on humans. DRI’s impactful science and inspiring solutions support Nevada’s diverse economy, provide science-based educational opportunities, and inform policymakers, business leaders, and community members. With campuses in Las Vegas and Reno, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit

About Nevada State College

Nevada State College, a four-year public institution, is a member of the Nevada System of Higher Education. Nevada State places a special emphasis on the advancement of a diverse and largely under-served student population. Located on a developing 512-acre campus in the foothills of Henderson, Nevada, the college was established in 2002 as a new tier in the state system between the research universities and the two-year colleges and, as such, is Nevada’s only state college. Nevada State College is one of the fastest-growing colleges in the country and the fastest growing in Nevada. It currently has more than 7,000 students and more than 800 full- and part-time employees. For more information, visit

About the Guinn Center

The Guinn Center is a policy research center, affiliated with the University of Nevada, Reno, with offices in both Las Vegas and Reno. The Guinn Center provides data-driven research and policy analysis. The Guinn Center seeks to identify and advance common-sense policy solutions through research , policy engagement, and strategic partnerships.

New DRI Internship Program Focuses on Mentorship for Inclusion in STEM

New DRI Internship Program Focuses on Mentorship for Inclusion in STEM

New DRI Internship Program Focuses on Mentorship for Inclusion in STEM

Oct 26, 2021

By Kelsey Fitzgerald

Career Development
Above: DRI Research Internship Immersion Program students Mary Andres (left) and John Cooper (right) work with faculty mentor Dr. Riccardo Panella in his laboratory on DRI’s Reno campus.
Credit: DRI.
Research immersion internships provide career-building opportunities for students from Nevada’s two-year colleges
From wildflower blooms to microplastics pollution, fourteen students from Nevada’s two-year colleges are spending this fall building career skills in exciting new directions.  The students are conducting hands-on research alongside DRI scientists in Reno and Las Vegas through DRI’s new Research Immersion Internship Program.

Although professional internship opportunities are fairly common in the sciences, many positions are aimed at students who are enrolled in four-year science degree programs. DRI’s new internship program takes a more inclusive approach, creating an opportunity specifically aimed at students from two-year colleges and welcoming those majoring in fields from outside of traditional scientific disciplines.

“Science and innovation thrive when people of diverse skillsets work together, because real-world problems are often very interdisciplinary,” said Internship Program Director Meghan Collins, M.S. “In addition to traditional scientific fields, drawing in students with interests in communications, business, public health, computing, and many other areas can bring new perspectives and new solutions to the table.”

Riccardo Panella and John Cooper in lab

DRI faculty mentor Riccardo Panella, Ph.D., (left) and student intern John Cooper (right) review calculations as part of an ongoing research project that tests a new therapeutic approach to treating metabolic disorders. Panella is an assistant research professor of cancer and genetics with the Center for Genomic Medicine at DRI; Cooper is a student at Truckee Meadows Community College. 

Credit: DRI.
DRI’s internship program began in September and runs for 16 weeks. Students have been placed in teams of two to four people, and are working under the direction of DRI faculty mentors from the Institute’s Reno and Las Vegas campuses on a variety of project themes.

One team of interns is working with Erick Bandala, Ph.D., assistant research professor of environmental science from DRI’s Las Vegas campus, to investigate water security in Native American communities of the Southwestern U.S. His team consists of three students from Nevada State College – two environmental studies majors and one math major.

“Many people in Native American communities lack access to running water in their homes and experience problems with water quality as well,” Bandala said. “We are exploring data that was collected by Tribes and water treatment facilities to learn about the scale of the problem and how it can be improved. I love the challenge and hope that my team will come out with helpful information. Water security is a very complicated issue, but the students that I am working with are very enthusiastic, and I am happy to be interacting with them.”

Other project themes for the program’s inaugural semester include documentation and analysis of wildflower superblooms (above-average bursts of blooming wildflowers) in the Western U.S., an investigation into the effects of wildfire on water repellency of soils, a study on how microplastic particles can be transported through the air, and a study investigating the effects of obesity on health challenges in mice.

Student intern Mary Andres
Riccardo Panella and Mary Andres

Above, left: Student intern Mary Andres from Truckee Meadows Community College prepares reagents needed to analyze lipid profiles and hepatic enzymes in a study being conducted by DRI’s Center for Genomic Medicine. The results of these experiments will pave the way for a new generation of RNA-based therapies to treat metabolic disorders and prevent cancer progression.

Credit: DRI.

Above, right: DRI faculty mentor Riccardo Panella, Ph.D., (left) of the Center for Genomic Medicine and Truckee Meadows Community College student Mary Andres (right) use a bright light to view a sample in Panella’s laboratory in Reno. 

Credit: DRI.
This year’s cohort includes students from Nevada State College, Truckee Meadows Community College, Great Basin College, and the University of Nevada, Reno. Because many of the students are early in their college journeys, or come from fields outside of the sciences, the internship program provides stepping-stones to help them build the fundamental skills they need to succeed, including a month-long period of training prior to implementing their projects.

At the end of the semester, the student teams will deliver their project results and receive feedback from their faculty mentors. The end goal is to help foster the next generation of diverse scientists through mentorship, inclusion, and skill building.

“There are a lot of independent internships available to science majors, but not many  programs that prepare students to be successful working in the sciences in the real world – especially for students who are coming from two-year college programs or from outside of scientific disciplines,” Collins said. “This program aligns with some of DRI’s larger goals of improving diversity and inclusion at DRI and in the sciences as a whole, while also providing important stepping-stones for students to learn to navigate the culture of science.”

Student Intern John Cooper

Student Intern John Cooper from Truckee Meadows Community College prepares reagents in Riccardo Panella’s laboratory at DRI in Reno, as part of DRI’s new Research Internship Immersion Program.

Credit: DRI.

More Information:

For more information on DRI’s Research Immersion Internship Program, please visit:

DRI faculty mentors for the Research Immersion Internship Program include Erick Bandala, Riccardo Panella, Eden Furtak-Cole, Markus Berli, Christine Albano, and Meghan Collins.


About DRI

The Desert Research Institute (DRI) is a recognized world leader in basic and applied environmental research. Committed to scientific excellence and integrity, DRI faculty, students who work alongside them, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge on topics ranging from humans’ impact on the environment to the environment’s impact on humans. DRI’s impactful science and inspiring solutions support Nevada’s diverse economy, provide science-based educational opportunities, and inform policymakers, business leaders, and community members. With campuses in Las Vegas and Reno, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit

New DRI projects for 2021 include microplastics, microfossils, snowmelt risk, and solute transport

New DRI projects for 2021 include microplastics, microfossils, snowmelt risk, and solute transport

New DRI projects for 2021 include microplastics, microfossils, snowmelt risk, and solute transport

FEB 26, 2021

Introducing the winners of DRI’s 2021 Institute Project Assignment (IPA) competition.

Each year, the Desert Research Institute awards funding to several new faculty and staff projects each year through its Institute Project Assignment (IPA) competition. Winners of the IPA competition receive a research grant from DRI to pursue a topic that interests them and develop ideas that can ultimately be turned into externally funded research projects. This year, winners of the IPA competition are DRI scientists Erick Bandala, Monica Arienzo, Sandra Bruegger, Benjamin Hatchett, and Lazaro Perez. Details about each project are below.

Erick Bandala and Monica Arienzo: Assessing environmental aging of microplastics

Microplastics, defined as plastic fragments smaller than 5mm, were first discovered in the natural environment in the early 2000s. Two decades later, much is still unknown about these pollutants – including how microplastic particles degrade or break down as they age. A new project led by Erick Bandala, Ph.D., and Monica Arienzo, Ph.D., will assess the environmental aging of microplastic particles through accelerated aging tests, using UV-A radiation to imitate the effects of unfiltered sunlight over different time spans on microplastics of different types, shapes, and sizes. Their results will provide new insight into the fate of microplastics after their release into the environment.

Closeup of microplastic fibers

A close-up image of microplastic fibers. Credit: DRI.

Benjamin Hatchett and Anne Heggli: Towards improved decision support for snow-covered watersheds: A snowmelt risk advisory

Rain-on-snow events (in which a warm winter storm rains onto existing snowpack under windy and humid conditions) are linked to many of the largest floods in Nevada and other parts of the United States. These types of events are projected to increase in frequency and magnitude as the climate warms. This change creates new challenges for water managers, who are tasked with deciding when water should be stored in reservoirs for economic and ecological benefits, and when water should be released downstream for flood control and public safety. To help water managers make decisions using the best available data, Division of Atmospheric Sciences graduate student Anne Heggli, advised by Benjamin Hatchett, Ph.D., will design and develop a tool called a Snowmelt Risk Advisory (SRA). This framework will combine risk matrices with weather datasets to create a tool that will help inform reservoir operations in snow-dominated watersheds.

A ski lift at Kirkwood ski resort during a warm storm

A rain-on-snow event at Kirkwood Ski Area. Credit: Ben Hatchett/DRI.

Sandra Brugger: Microfossils in Greenland Ice – Establishing a new method at DRI

Greenland’s ice sheets hold important records of pollen grains and other microfossils that can provide researchers with insight into long-term environmental change in the Arctic, however, these resources have not yet been studied extensively. Recently, Sandra Brugger, Ph.D., developed a new method for extracting microfossils from Greenland ice cores and created the first reliable record of microfossils from well-dated Greenland ice, with a second record currently under development. With IPA funding, Bruegger will hold a workshop to train additional scientists in her methodology, and develop a microfossil record from east-central Greenland ice spanning the past 8000 years. She will also give a talk to the local community at the Alta Skilled Nursing and Rehabilitation Center in Reno, sharing her research with an audience that has been isolated for months during the pandemic.

DRI scientist Sandra Brugger inspects samples under a microscope. Credit: Manu Friederich

DRI scientist Sandra Brugger inspects samples under a microscope. Credit: Manu Friederich.

Lazaro Perez: Tortuosity Characterization via Machine Learning to Quantify Solute Transport in Berea Sandstone

Understanding and predicting the fate of solutes (dissolved substances) as they pass through various types of rocks and soils in a groundwater system is crucial for several environmental and industrial applications, but modeling this process is complex. Building on work completed as part of an IPA-funded project in 2020, Lazaro J. Perez, Ph.D., will use training data for the development of a machine-learning algorithm to predict solute transport through material containing pores of different sizes, such as sandstone. Dr. Perez’s work, focused on solute transport simulations on pore-scale images of two types of sandstones, will help scientists better understand processes as diverse as contaminant transport in groundwater flow and protein diffusion in living cells.

DRI scientist Lazaro Perez

DRI scientist Lazaro Perez.

DRI scientists investigate effectiveness of heat warnings along US-Mexico border

DRI scientists investigate effectiveness of heat warnings along US-Mexico border

DRI scientists investigate effectiveness of heat warnings along US-Mexico border

AUG 25, 2020

Population Heath

Above: Aerial view of California’s Imperial Valley, where daytime temperatures during summer months can reach as high as 120 degrees. Credit: Thomas Barrat/

Featured research by DRI’s Kristin VanderMolen, Ben Hatchett, Erick Bandala, and Tamara Wall


In July and August, daytime temperatures along parts of the US-Mexico border can reach as high as 120 degrees – more than 20 degrees above normal human body temperature. For agricultural workers and others who live and work in the region, exposure to these extreme high temperatures can result in serious health impacts including heat cramps, heat exhaustion, heat stroke, and heat-related death.

Although the National Weather Service and public health organizations issue heat warnings to communicate risk during extreme heat events, heat-related illness and death are still common among vulnerable populations. Now, a group of DRI scientists led by Kristin VanderMolen, Ph.D., Assistant Research Professor with DRI’s Division of Atmospheric Sciences, is trying to figure out why.

“With the continued increase in episodes of extreme heat and heat waves, there has been an increase in warning messaging programs, yet there continue to be high numbers of heat-related illness and death in communities along the US-Mexico border,” VanderMolen said. “So, there’s this question – if agencies are doing all of this messaging, and people are still getting sick and even dying, then what’s going on?”

An agricultural field in California’s Imperial Valley

An agricultural field in California’s Imperial Valley, where DRI researchers are exploring questions about heat messaging and vulnerability in populations of agricultural workers and others who are vulnerable to heat-related illness and death. 

Credit: Winthrop Brookhouse/

Assessing heat messaging: An interdisciplinary approach


In 2018, VanderMolen and colleagues Ben Hatchett, Ph.D., Erick Bandala, Ph.D., and Tamara Wall, Ph.D. received funding from NOAA’s International Research and Applications Project (IRAP) to explore questions about heat messaging and vulnerability in two pairs of US-Mexico border cities, San Diego-Tijuana and Calexico-Mexicali. Collectively these areas form the boundaries of the Cali-Baja Bi-national Megaregion. This unique transboundary location integrates the economies of the United States and Mexico, exporting approximately $24.3 billion worth of goods and services each year.

With expertise in the areas of anthropology, meteorology, climatology, and population health, this interdisciplinary team of researchers is now working on this problem from several angles. They are using climate data to characterize and assess past heat extremes as well as using long-range weather forecasts and climate projections to help improve the ability to put out advance messaging about future heat waves. They are working to identify and map populations that are particularly vulnerable to extreme heat and are collaborating with local agencies to understand why people may or may not take protective action during heat waves.

From initial conversations with local civic organizations and public health agencies, the team has learned that the reasons people may not be following heat warnings are complex. Recommended actions such as “stay indoors and seek air-conditioned buildings,” or “take longer and more frequent breaks,” may not be realistic for agricultural workers or others who don’t have access to air-conditioned spaces. There can even be negative consequences for those who choose to seek medical help.

“A big piece of the story that we’ve heard from some of the independent groups that work with agricultural workers in the region is that if someone gets sick and doesn’t show up for work, they can lose their job,” Hatchett explained. “If they go to the hospital and somebody sees them or hears about it, they can lose their job. There are some really big issues related to people not feeling okay with trying to get the help they need.”

“There is evidence to suggest that cases of heat-related illness and death are underreported, probably severely underreported,” VanderMolen added. “The demographics of the individuals for documented cases don’t reflect the population demographics overall. We know that there are a lot of inequalities in that area that may get in the way of people reporting illness.”

A map of summer maximum near-surface temperatures in Imperial Valley, CA

A map of summer maximum near-surface temperatures over the 30-year period from 1981–2010 shows that Imperial Valley (at the border between Mexico and the southeastern corner of California) is the hottest place in in North America, with an average maximum temperature from June to August of 40° Celsius (104° Fahrenheit). Data is from the North American Regional Reanalysis.

Credit: Ben Hatchett/DRI

COVID-19 complications and next steps


Originally, VanderMolen was planning to travel to the US-Mexico border this summer to do one-on-one interviews with members of vulnerable populations, but the COVID-19 pandemic has resulted in unforeseen complications.

Imperial County has been hit very hard by COVID-19, compounding the effects of extreme heat for the vulnerable populations that VanderMolen and her team hope to work with. The pandemic has also made it unfeasible to travel to the region to do face-to-face interviews, and has created challenges in coordinating with local agencies that are now overwhelmed in their efforts to address COVID-19.

“It’s a really interesting place and time to do this work because there are questions about what it means to be on stay-at-home orders and limited travel orders when it’s 114 degrees outside and you don’t have reliable air conditioning or its cost is prohibitive,” VanderMolen said. “At the same time, because they’re so overwhelmed right now with caseload, most folks in the area can’t really afford to address issues beyond COVID-19.”

As the research team works to navigate a path forward that is safe for both the interviewers and interviewees, they remain committed to developing information that will help vulnerable populations along the border.

“I hope that the information we provide is something decision-makers can use to make the right decision or create legislation that can help protect workers in the field, or at least call attention to the kind of inequalities and risk that the people there are being exposed to,” Bandala said. “Or, if we can produce information to change the mindset of the people to start thinking of themselves as a population at risk, and put more attention on the heat warnings, that will suffice for me to feel satisfied with the results of our research.”

The US-Mexico border is just one of many places around the globe where heat-related illness is a problem, added Hatchett – and many of those places happen to be where a lot of our food is grown or where important industries are located.

“I think this is a somewhat ubiquitous problem around the planet. We have these really important places that are susceptible to environmental extremes and these people that we rely on to have these regions be productive in terms of agriculture or industry. Unfortunately, those people are often the most susceptible and underserved populations to these compound environmental hazards,” Hatchett said. “It’s so easy to forget them, but one of the goals of this project is really to bring to light the importance of aiming much-needed resources at trying to help those populations and those places.”

Additional information

For more information on the members of this DRI research team, please visit: 

This research was supported by NOAA’s International Research and Applications Project (IRAP).

Engineered Processes for the Separation and Degradation of Microplastics in Freshwater

Engineered Processes for the Separation and Degradation of Microplastics in Freshwater

Photo: The sand band used to prepare hydrochar from microplastics. Credit: Erick Bandala/DRI.


By Nicole Damon, Nevada Water Resources Research Institute

Microplastics, plastic fragments that are smaller than 5 mm in any dimension, have been found in ecosystems worldwide. These emerging contaminants are even in environments that are supposed to be free from human contact, such as Antarctica and the deep ocean floor, and their toxic properties make them a significant environmental hazard.

“After the first acknowledgement of microplastics in the early 2000s, their presence in the environment has raised ever-increasing concerns because of their effects on organisms and ecosystems, and because approximately 1.5 million tons of microplastics are estimated to be released into aquatic environments every year,” explains Dr. Erick Bandala, the principal investigator of this project, which also includes Dr. Menake Piyasena from New Mexico Tech, graduate research assistants Adam Clurman and Ahdee Zeidman, and summer intern Yajahira Dircio. “Unfortunately, very little is known about the capability of engineered separation and/or degradation technologies to remove this highly ubiquitous contaminant.”

Commercial products that are manufactured to contain microplastics—such as personal care and pharmaceutical products, industrial abrasives, drilling fluids, and 3D printing products—are the primary sources of microplastics. However, the degradation of plastic debris can also generate microplastics.

“Wastewater treatment plant effluents are the main pathway for microplastics to be released into aquatic environments,” Bandala says. “Although the microplastic removal rate of a conventional wastewater treatment plant is reported to be in the range of 73 to 79 percent, the treated effluent can carry as much as 220,000 to 1.5 million microplastic particles per day.”

Yajahira Dircio, a student at Rancho High School and summer intern on the project, is preparing hydrochar from MPs using a sand band

Yajahira Dircio, a student at Rancho High School and summer intern on the project, is
preparing hydrochar from MPs using a sand band. Credit: Erick Bandala/DRI

In recent years, the effects microplastics have been found to have on aquatic species and their unknown effects on human health have increased concerns about their presence in water sources.

“Because conventional water treatment processes are unable to effectively eliminate microplastics in water, developing new technologies that can separate them from effluents and prevent their release into the environment is a high priority to protect water quality and water security,” Bandala says.

For this project, the researchers will use acoustic focusing and electrocoagulation to separate microplastics in freshwater effluents and determine the removal process mechanisms.

“Acoustic standing waves are a fast, noncontact, gentle particlemanipulation technique for microfluidic conditions that have emerged as a promising new technology for the purification, separation, and concentration of beads and biological cell samples,” Bandala explains.

The researchers will also assess the efficacy of using electrocoagulation to remove MPs from wastewater.

“Electrocoagulation has several significant advantages to conventional chemical coagulation, such as it increases treatment efficiency, generates less sludge, requires less space, and prevents chemical storage,” Bandala adds. “It has been proven to be highly efficient in removing contaminants. Our research group has used it for water defluoridation and to pretreat effluents that were heavily contaminated with petrochemicals.”

Because microplastics in freshwater are increasingly detected, it is even more important to find effective water treatment process that remove them.

“Although ultrafiltration, or microfiltration, have microplastic removal efficiencies as high as 99.4 percent, they also have high operational and maintenance costs and require skilled operators,” Bandala explains. “Finding efficient, costeffective methods to separate microplastics from freshwater effluents is critical to preventing population exposure.”

Adam Clurman, an undergraduate student at Nevada State College, is conducting the electrocoagulation experiments for the project.

Adam Clurman, an undergraduate student at Nevada State College, is conducting the
electrocoagulation experiments for the project. Credit: Erick Bandala

Another challenge that microplastics in freshwater present is how to dispose of them once they are removed from water. For this project, the researchers will use advanced oxidation processes (AOPs) as complementary processes to degrade the plastic waste after it has been separated from the wastewater. Advanced oxidation processes are an eco-friendly way to degrade organic compounds. In previous projects, the research group has tested the capability of these processes to degrade a wide variety of dissolved organic contaminants in water.

“Advanced oxidation processes have been used to degrade organics and have shown high cost-efficiency and short detention time compared with conventional water treatment processes,” Bandala explains. “Using AOPs to degrade microplastics will not only be an interesting challenge because of the complexity of their polymeric chains, but also because these contaminants are suspended in water and treating contaminants in a different phase in water using AOPs has not yet been reported.”

Maintaining the quality of water sources is an increasing issue, particularly in arid and semiarid regions with rapidly growing populations, such as Nevada.

“Desert Research Institute has reported the presence of MPs in places such as the Sierra Nevada and Lake Tahoe, which are the origin of several drinking water supply systems in Nevada,” Bandala explains. “We live in a region with a moderate-high water stress and as Nevadans, we need to protect our water sources from contamination to ensure the sustainable development of our communities.”

This story was originally written for the Nevada Water Resources Research Institute (NWRRI) Summer 2020 Newsletter. Success and the dedication to quality research have established DRI’s Division of Hydrologic Sciences (DHS) as the Nevada Water Resources Research Institute (NWRRI) under the Water Resources Research Act of 1984 (as amended). The work conducted through the NWRRI program is supported by the U.S. Geological Survey under Grant/Cooperative Agreement No. G16AP00069.

For more information on the NWRRI, please visit: 


Researchers identify connection between more frequent, intense heat events and deaths in Las Vegas

Researchers identify connection between more frequent, intense heat events and deaths in Las Vegas

Photo: Hotter temperatures and longer, more frequent heat waves are linked to a rising number of deaths in the Las Vegas Valley over the last 10 years.


Las Vegas, Nev. (June 4, 2019) – Over the last several decades, extreme heat events around the world—particularly in the North American Southwest—have gotten hotter, occurred more frequently, and lasted longer. These trends pose significant health risks to the growing number of people making cities like Las Vegas home.

A new study by faculty and undergraduate students at the Desert Research Institute (DRI), Nevada State College, and Universidad de Las Americas Puebla traces the relationship between extreme heat and mortality rates, identifying a clear correlation between heat wave episodes and heat-related deaths in Las Vegas over the last ten years.

“Current climate change projections show an increased likelihood of extreme temperature events in the Las Vegas area over the next several years,” explained Erick Bandala, Ph.D., assistant research professor at DRI and lead author on the study. “Understanding recent extreme heat trends and their relationship to health hazards is essential to protecting vulnerable populations from risk in the future.”

Researchers analyze data on computer.

Erick Bandala, PhD (left), shows a graduate student the data he and his team analyzed for this study.

Urban areas of the Southwest are of particular concern because several factors compound the health-related risks of extreme heat events. The heat-absorbing properties of common materials like asphalt exacerbate already high temperatures in cities (called the urban heat island effect), particularly at night. What’s more, populations in cities like Las Vegas are growing rapidly, especially among those 55 and older, which means that more and more people are exposed to risk.

In this study, the research team analyzed two measures of extreme heat—heat index and excess heat factor—for the Las Vegas metropolitan area in the June, July, and August months from 2007 to 2016. Heat index (HI) accounts for how the human body reacts to surface temperature and relative humidity. Excess heat factor measures (EHF) heat wave intensity in relation to historic temperature trends to account for how acclimated the public is to a given temperature threshold. Because both HI and EHF incorporate the human body’s response to extreme heat, they are ideal metrics for assessing public health impacts, and both were shown to rise over the study period.

The annual average of severe heat events per year in Las Vegas also showed significant increases in this study, from an average of 3.3 events per year from 2007-2009 to 4.7 per year in the 2010-2016 period. These findings match historic trends, which show a steady increase in severity and frequency of excess heat in Las Vegas since 1980.

Strikingly, the number of heat-related deaths in Las Vegas map onto these trends: as heat wave intensity increases, the number of heat-related deaths does, too.

Graphs of heat index and excess heat factor.

Heat Index (HI) and Excess Heat Factor (EHF) are metrics that go beyond just temperature to also account for the human body’s response to heat. This study found that rising trends in these measures tracked closely with the number of heat-related deaths in Las Vegas.

“From 2007 to 2016, there have been 437 heat-related deaths in Las Vegas, with the greatest number of those deaths occurring in 2016,” explained Bandala. “Interestingly, 2016 also shows one of the highest heat index measures over the last 35 years. This shows a clear relationship between increasingly intense heat events in our area and public health effects.”

Bandala’s team found that the subpopulation particularly at risk of heat-related deaths is adults over 50 years old—76% of the heat-related deaths in the study period were individuals in this subpopulation. Of the deaths in this group, almost all individuals also showed evidence of pre-existing heart disease. Researchers note that these findings are highly significant given that the population of adults over 50 in Las Vegas is increasing, with more retirees choosing Clark County as a retirement destination.

Only 23% of heat related deaths occurred in the subpopulation of adults aged 20 to 50 years; interestingly, the most common pre-existing condition for this group was drug and alcohol use. More research is needed to understand how heat is impacting this segment of the population, Bandala noted, because though the number of deaths in this group is comparatively smaller, it is still nearly one quarter of heat-related deaths in the Las Vegas Valley. Additionally, this subpopulation includes economically active adults.

With more intense, more frequent, and longer lasting heat events projected in the coming years, the research team hopes that the trends identified in this study can assist local decision-makers in taking steps to protect the most vulnerable groups in Las Vegas.

“This research helps us better understand the connection between the climate changes we’ve experienced in Las Vegas and their impact to public health over the last 35 years,” Bandala said. “Ideally, this data analysis will help our community adapt to the changes yet to come.”

The full study, titled “Extreme heat and mortality rates in Las Vegas, Nevada: inter-annual variations and thresholds”, is published in the International Journal of Environmental Science and Technology. The study abstract and references are available here: 

This study is based on work supported in part by the National Science Foundation, NASA, and the Desert Research Institute. Other members of the project team include Kebret Kebede, Nikole Jonsson, Rebecca Murray, and Destiny Green, all of Nevada State College; John Mejia of DRI; and Polioptro Martinez Austria of the Universidad de Las Americas Puebla. 

Meet Erick Bandala, Ph.D.

Meet Erick Bandala, Ph.D.

Erick Bandala, Ph.D., is an assistant research professor of environmental science with the Division of Hydrologic Sciences at the Desert Research Institute in Las Vegas. Erick specializes in research related to water quality and water treatment, including the use of nanomaterials in developing new water treatment technologies. He is originally from Mexico, and holds a bachelor’s degree in chemical engineering from Veracruz State University, a master’s degree in organic chemistry from Morelos State University, and a Ph.D. in Engineering from the National Autonomous University of Mexico. Erick has been a member of the DRI community since 2016, when he moved to Las Vegas to begin his current job. In his free time, Erick says that he enjoys doing nothing – a passion that is not shared by his wife of nearly 30 years, who enjoys doing many things.

DRI: What do you do here at DRI?

EB: My work here is to develop advanced technologies for water treatment, such as processes that can deal with the pollutants in the water that are not removed by conventional water treatment methods.

DRI: We understand that a lot of your work involves nanomaterials. What are nanomaterials, and how do you use them in your research?

EB: Nanomaterials are materials that are so small that if you compare the size of one of these materials with a basketball, it’s like comparing the size of the basketball with the size of the earth. These nano-sized materials have applications in many different fields.

In my case, what I’m doing with the nanomaterials is using them to promote reactions in the water that can produce chemical species capable of destroying contaminants. Not only to remove the contaminants, but to destroy them from the water.

Erick Bandala, Ph.D. at work in DRI's Environmental Engineering Lab. Credit: Dave Becker, Nevada Momentum.

Erick Bandala, Ph.D. at work in DRI’s Environmental Engineering Lab. Credit: Dave Becker, Nevada Momentum.


DRI: What type of contaminants do you hope to remove? Can you tell us about one of your projects? 

EB: Right now, we are trying to get nanoparticles made of something called zerovalent iron, which is iron with no charge on it. We are planning to use this to remove antibiotics from water. As you know, we all use antibiotics every now and then. And when you use them, the antibiotics get into your body and you will probably only use about 15 percent of the total amount that is present. Whatever remains is discarded with your feces or urine into the wastewater.

Once the wastewater arrives at the water treatment plant, the conventional water treatment processes will probably not be able to remove the antibiotic. So, the antibiotic passes through the wastewater treatment system and keeps going with the treated effluent. In the case of Las Vegas for example, it goes back to Lake Mead. This is a problem, because we are learning now that bacteria can become resistant to antibiotics just by exposure – and when bacteria in the environment become resistant to the antibiotics, there is no way for people to treat infections.

So, in our work, we hope to use nanoparticles to destroy the contaminants in the wastewater. At the moment we are just running some trials in the lab, but we eventually hope to run the experiment at pilot level to see if we can treat wastewater coming back from plants to the lake, and ensure that we will not have these contaminants going back to our environment.

Another part of my research is on how to use solar energy to remove contaminants from water. This way you can save some money by using an energy source that is common in Nevada, widely available. We have a lot of sunshine here.

Information about nanomaterials from DRI's Environmental Engineering Lab. Credit: Dave Becker, Nevada Momentum.

Information about nanomaterials from DRI’s Environmental Engineering Lab. Credit: Dave Becker, Nevada Momentum.


DRI: How did you become interested in working on water treatment and water quality?

EB: My very first job was working in a research institute in Mexico that was devoted entirely to water. The group that I arrived to work with was dealing with water quality and treatment in wastewater and drinking water. So, I started down this path just because it was available and I needed the job – but my plan was to spent two years working on this and now it has been more than 25 years. I feel very passionate about this field of work. I feel like this is the way that I have to try to help people, and I love it.

DRI: You are originally from Mexico. What brought you to DRI?

EB: When the position at DRI opened three years ago, I started learning about the water related issues that Nevada and particularly Las Vegas was facing, and was fascinated. The city gets its water supply from Lake Mead then sends treated wastewater back to the lake — so having almost 100 percent recycling of the water is something that caught my attention immediately. Not only because it’s wonderful, but that it may also result in other problems like the recycling of some pollutants that you probably don’t want in your drinking water. That idea really captured me. So I decided to apply for the job, and have had three years of great fun trying to deal all of those problems and promote some solutions that may help to deal with the reality we’re facing in Las Vegas. Reno is not that different – we all need water when we’re living in places where water resources are so scarce. I was really intrigued by how to deal with all of these problems and how I might help.

Erick Bandala (second from left) and his colleagues from DRI's Environmental Engineering Lab. 

Erick Bandala (second from left) and his colleagues from DRI’s Environmental Engineering Lab.


For more information about Erick and his research, please visit: