A researcher’s quest to clean Nepal’s water leads to an unexpected journey

Environmental biologist comes up with a novel solution to remove arsenic from Nepal’s water supply

By Alison Bert, DMA - January 15, 2020  7 mins
Tista and researcher in field
As a researcher at the Nepal Academy of Science and Technology (NAST), Dr. Tista Prasai Joshi (right), collects a river water sample with Research Assistant Lerensa Shrestha in the Nuwakot District, near Kathmandu. They are monitoring water pollution. (Photo by Mahesh Kafle)

In her studies as an environmental biologist, Dr. Tista Prasai Joshi has been tackling a problem that has sickened thousands in rural Nepal.

Her search for a solution began 17 years ago when, as a master’s student, she was granted a research opportunity at the Nepal Academy of Science and Technology (NAST).

Her journey would ultimately take her more than 2,000 miles from home to a world-renowned research institute. In 2013, she was awarded a scholarship to pursue a PhD in Environmental Engineering at the University of the Chinese Academy of Sciences (UCAS) in Beijing.

Manas Joshi, Tista’s only son, at age 7.On March 23, 2013, Tista hugged her 7-year-old son, Manas, goodbye. He would stay with her extended family while she pursued her research there, returning for a visit once a year during holidays. She recalled her son’s advice before she departed:

He told me, ‘Mom, just pass the PhD – don’t you fail.’

Her family has always supported her pursuit of science, including her husband, Dr. Dev Raj Joshi, who is Associate Professor of microbiology at Tribhuvan University, Nepal.

“He always supported me and … always mentored me,” Tista said.

Her late mother, Sanu Baba Prasai, “was a real inspiration for my career development,” Tista added. “She always encouraged me to pursue my PhD because she wanted her daughter to become a doctor.”

And her son is fascinated with science, often quizzing his mother. “Oh, he asks me so many funny, funny questions,” Tista said. “And sometimes he also challenges me: ‘You are a scientist, but you cannot answer it?’” She laughed.

“I am a scientist in a particular field, but he thinks that I should know everything about science.”

Working through weekends and summers

In China, she immersed herself in her research, working late hours in the lab. And she was not alone. “I had one lady teacher – she was so hard working,” Tista recalled. “She came to the office at 7 o'clock (in the morning), and sometimes she worked until midnight. It was really amazing, and I was always thinking, ‘Oh I have to live this way.’

Tista with teacher Lihui Zhao
Dr. Tista Prasai Joshi (right) with Lihui Zhao, Lab Manager for the Water Purification Research Group at Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences (RCEES), of the Chinese Academy of Sciences (CAS), Beijing. “Ms. Zhao is kind and helpful in the laboratory and loves hard working students,” Tista said. (Photo by Dr. Jinsong Liang)

So Tista took no breaks, working through weekends and the summer holidays with the few team members who stayed on in the lab.

Her son kept her on task, asking her when she would finish:

I told him every time, ‘I need to write a paper, without a paper, I cannot have a PhD.’ And he always asked me, ‘Mom, how many papers do you have published?’

Her hard work paid off. Based on her publications, she was awarded the Excellent International Student Award from the University of the Chinese Academy of Sciences (UCAS) in 2017. There, she worked under the supervision of Academician Prof. Jiuhui Qu and Prof. Ruiping Liu, leading scientists in the field of water purification in China, at the Research Center for Eco-Environmental Sciences (RCEES), CAS.

Tista with Professor Ruiping Liu
Tista Prasai Joshi with Prof. Ruiping Liu, PhD, in 2017.

“I felt so proud to work with their prestigious research group,” she said.

They went on to publish their research in high-impact journals.

Read the research they published with Elsevier

These articles are freely available until January 13, 2021.

Removing toxins from drinking water

When Tista returned to Nepal in 2017, she resumed her research at NAST, furthering her research to improve the quality of drinking water.

As a master’s student in microbiology at Tribhuvan University, Tista had worked with NAST to screen indigenous herbal extracts to remediate waterborne enteric pathogens.

Now, she applies novel metal oxide adsorbents to remove harmful organic and inorganic arsenic compounds from water efficiently. Her primary aim has been to develop economic and environmentally friendly techniques for the treatment of water. In addition to raising public awareness, this work has had a significant impact on the accountability of drinking water suppliers in Kathmandu.

In addition, her lab has tested and found coliform bacteria in the water. While coliform is not harmful in itself, it is an indicator that disease-causing organisms may be present. As a result, her lab urges the public to treat their water before drinking it.

Adsorption technology for the removal of pollutants is new for Nepalese water suppliers. Tista is advocating the adoption of this technology in Nepalese water supply systems. Bench-scale models in her laboratory have indicated that adsorbents she has developed would be effective in mid- or large-scale water treatment facilities.

Alternatively, Tista has recommended using aeration and filtration techniques at the household level to remove water contaminants. Disease-causing microbes are commonly eliminated by boiling for sufficient time.

Awards help her advance research amid funding restraints

Tista receiving medal of from President of Nepal
For her PhD research, Dr. Tista Prasai Joshi receives the medal “Nepal Bidhya Bhusan Ka” from Right Honorable President of Nepal Bidya Devi Bhandari. (Photo: Department of information and broadcasting, Government of Nepal)

Pursuing scientific research in the developing world is fraught with challenges. In a recent email, Tista wrote:

I am struggling every day. We have less funding for research work and limited manpower and resources. I want to solve so many questions of the people regarding water quality issues. Now I am working hard and try to figure them out.

Two recent awards she received are helping her pursue this research while mentoring four of her master’s students at NAST.

Tista Prasai Joshi at AAAS
Dr. Tista Prasai Joshi talks about her research at the AAAS Annual Meeting in Washington, DC, as she accepts a 2019 OWSD-Elsevier Foundation Award for Women Scientists in the Developing World. (Photo by Alison Bert)

Last year, Tista received two major international honors. In February, she was one of five researchers to receive the 2019 OWSD-Elsevier Foundation Awards for Early-Career Women Scientists in the Developing World at the American Association for the Advancement of Science (AAAS) Annual Meeting.

“Receiving this prestigious award has great value in my scientific career,” she said. “Because of this international recognition, I am more confident, accountable and motivated to continue my research activities to achieve my goal. It will inspire many younger ladies in this region to achieve more in the advancement of sciences.”

Then in August, she was named a 2019 OWSD Early Career Fellow. Each of these fellows will receive up to $50,000 to lead research projects at their home institutes and to build research groups that will attract international visitors.

Advice to young scientists

Tista urges young researchers to think about problems that need solving:

My best advice is just to focus on your research work – and think about the needs of your country. That way, we can also solve problems by using science for society.

The science behind Tista’s research

Aromatic organoarsenic compounds such as para Arsanilic acid (p-ASA) and Roxarsone (ROX) are extensively used as feed additives in poultry. Upon entering the environment, aromatic organoarsenic tends to transform into more mobile toxic inorganic arsenic by microbial activities, which can inadvertently spread toxic inorganic arsenic through the environment to surface and groundwater sources, causing serious impact on human health. Removal of aromatic organoarsenic compounds from the poultry manure or contaminated water may break the organoarsenic transform into the environment.

Tista developed and tested the efficacy of novel adsorbents for the removal of pollutants from water. She applied iron-manganese based (Fe-Mn) adsorbents for the treatment of aromatic organoarsenic compounds in water. She has made significant contributions in drinking water science and technology by understanding the interactions of organoarsenic compounds with iron and manganese based adsorbents to explore their adsorption efficiency and removal mechanism and development and optimization of adsorbents. Based on the combined results of macroscopic and microscopic characterization techniques exhibited the adsorption and oxidation mechanism for the removal of organoarsenic compounds. Her research has potential engineering treatment application as highly-efficient and cost-effective technology in a small community to large scale purification of water and also in reclamation of arsenic and heavy metals.

Another aspect of Tista’s research explored microbial contamination in various drinking water sources in Nepal, which has had a major impact on public awareness and the accountability of drinking water suppliers in Kathmandu. Dr. Tista and her colleagues’ promotional activities for household water treatment techniques have motivated members of several communities to use safe water and minimize waterborne infections in their city.


Written by

Alison Bert, DMA

Written by

Alison Bert, DMA

As Executive Editor of Strategic Communications at Elsevier, Dr. Alison Bert works with contributors around the world to publish daily stories for the global science and health communities. Previously, she was Editor-in-Chief of Elsevier Connect, which won the 2016 North American Excellence Award for Science & Education.

Alison joined Elsevier in 2007 from the world of journalism, where she was a business reporter and blogger for The Journal News, a Gannett daily newspaper in New York. In the previous century, she was a classical guitarist on the music faculty of Syracuse University. She received a doctorate in music from the University of Arizona, was Fulbright scholar in Spain, and studied in a master class with Andrés Segovia.

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