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Wednesday, February 07, 2018, 11:05
Arsenic and old nails
By Zhang Zefeng
Wednesday, February 07, 2018, 11:05 By Zhang Zefeng

Students from the Rural International Student Exchange program at Tsinghua University are helping villagers in Shanxi province purify drinking water. Zhang Zefeng reports.

Former RISE president Kate Smith and Taiyuan University of Technology student Li Zhilin check water samples taken from Liangjiabu village in North China's Shanxi province. (PHOTO PROVIDED TO CHINA DAILY)

Even in his childhood, Liang Honggang had the impression the water quality in his village was poor. However, he didn't fully realize how bad it was until he attended high school in the nearby city of Pingyao and had access to tap water.

"The water just tastes different," says Liang, now a 23-year-old graduate of Taiyuan University of Technology. "Back home, the water is smelly, especially during summer."

This is not that surprising since the water in the small village of Liangjiabu in Shanxi province is primarily untreated groundwater from two wells.

Arsenic is not something that you can see, smell or taste. Only if someone tells you it’s there, (then) can you know it’s there

Kate Smith, Australian PhD candidate at Tsinghua University’s School of Environment

But aside from having the odor and sediment, the water is also contaminated with arsenic.

Last summer a team of 13 students from Rural International Student Exchange at Tsinghua University, a nonprofit organization dedicated to solving rural environmental problems in China, visited the village and tested the water.

According to the test result of the RISE team, the main well in Liangjiabu had an arsenic concentration of over 200 micrograms per liter, far exceeding the World Health Organization safety standard of 10 micrograms per liter.

Cao Yining, a 21-year-old environmental engineering major of Tsinghua University, is the current team leader. While visiting the village, she was astounded by the quality of local drinking water.

"I feel powerless as there is little we can do," she said.

The arsenic is the result of the local geological conditions, the Taiyuan and Datong basins in Shanxi have arsenic, and the area also has the natural conditions for arsenic to enter the groundwater.

Among the regions and provinces in China, 20 have water naturally contaminated with arsenic. Apart from Shanxi, certain areas among regions including the Xinjiang Uygur autonomous region, the Ningxia Hui autonomous region and Jilin province suffer from severe contamination, says Zhang Fang, assistant professor, School of Environment, Tsinghua University.

The greatest threat to public health from arsenic originates from contaminated groundwater. Long-term exposure to arsenic through drinking-water and food can lead to skin cancer, skin lesions, cardiovascular disease and diabetes, according to WHO.

A volunteer collects a sample of filtered water from the sand-iron filter that is installed in around 70 households in the same village. (PHOTO PROVIDED TO CHINA DAILY)

Research endeavor

Starting in early 2015, students from RISE have been going back and forth between Beijing and Pingyao working on ways to reduce the arsenic level in the local drinking water.

To come up with a low-cost arsenic removal technique, Kate Smith, an Australian PhD candidate at Tsinghua's School of Environment, spent days experimenting with different filters.

In total, she and her colleagues tested seven versions of sand-iron filters trying to identify which was the cheapest and most effective at removing arsenic.

"We thought that we were building a filter that was really good," says Smith. "But it didn't work."

"The best results were from a filter with nails in the sand which we didn't expect," she says.

Last summer, if you happened to visit Liangjiabu, you would have probably encountered the 13 students squatting in the sun cleaning the simple water purifiers, which are essentially buckets containing different layers of sand and rocks with five kilograms of iron nails on the top.

Rust from the iron adsorbs the arsenic and when the arsenic sticks to the rust, it is removed from the water, says Smith.

But good as that sounds, while removing the arsenic, the filter also produces rust, which directly affects the water quality, so they had to add another bucket to filter out the rust.

"Solving problems makes new problems," she says. "And you have to make the water purification equipment accessible both in terms of price and maintenance."

In the first five months of the experiment, they successfully reduced the arsenic to below 50 micrograms per liter at the cost of 136 yuan (US$22) per filter.

The results were later turned into a research paper published by Chemosphere, a peer-reviewed international scientific journal.

"Our aim was always to find where there's a problem and provide a solution," says Smith. "We've had a lot of results, so I thought we should work it into a paper, as that might help others."

Altogether the group has installed about 70 filters, directly benefiting over 280 people in the area.

Liang has been assisting with the program since its beginning. He says the program solved a very practical issue for villagers.

"For poorer people, the filter offers them access to better drinking water," he says.

On the other hand, the project also brought attention and spread awareness of water safety among villagers. In the past years, Liang has been seeing an increasing number of households buy water purifiers including commercial ones to clean their drinking water.

"Arsenic is not something that you can see, smell or taste. Only if someone tells you it's there, (then) can you know it's there," says Smith.

Li Zhenyu, an associate professor at School of Environment of Tsinghua University, appreciates the efforts taken by RISE.

"The research program, participated in by both international and domestic students, focuses on improving the living standard of the rural residents," says Li. "The topic, the research methods they employed and their aspirations should be recognized."

Li also suggests RISE should continue standardizing the arsenic removal project and work on areas including solid waste treatment so that the concentrated arsenic won't cause secondary pollution.

This year, a new central water supply project covering three local towns and 56 villages including Liangjiabu will be constructed, according to Li Ansheng, a local governmental official in Pingyao.

The project, which is scheduled to start in March, is expected to benefit nearly 80,000 local people and fundamentally solve the arsenic contamination issue.

Volunteers retrieve water samples from a well in Liangjiabu. (PHOTO PROVIDED TO CHINA DAILY)

Beyond the experiment

Sam Lee, a former member of the RISE program from the University of Michigan, took a field trip to Pingyao, which, he says, enabled him to see a different part of China.

"It was nice to learn more about the local people and culture," he says.

While for Muhammad Khan, a Pakistani student, being a part of the arsenic removal program has inspired him to solve similar issues back home.

He grew up in Lahore in eastern Pakistan, where the levels of arsenic in the groundwater are also very high. A study in the journal Science Advances found that 50 to 60 million people in the country use groundwater with likely over 50 micrograms per liter arsenic contamination.

"This is the problem we are facing in my country," he says. "RISE has conducted and implemented the project in Shanxi province, which was very successful."

Khan once organized a medical camp offering free medication to poor people, and says most people who asked for medicine were sick due to the arsenic contamination of the water.

"The core problem is the water. It's not the disease," says the PhD candidate from Tsinghua's School of Environment. "We have to target the primary cause instead of spending money on medicine."

This year, Khan plans to work with other RISE members on a research project in Pakistan among arsenic concentrated areas like Lahore and Tharparkar.

"I will definitely involve the students in my country from different universities to collaborate with the RISE program to make a joint group for helping people who are drinking contaminated water," he says.

"It will bring a positive change and improve the lives of the poor people who don't have enough money to support themselves."

Prior to the project in Pingyao, the RISE team worked on water-related projects in Gansu province and in Ningxia.

Contact the writer at zhangzefeng@chinadaily.com.cn


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