As many as 70 million Bangladeshis have been exposed to arsenic, which occurs naturally in groundwater, through tainted tube wells installed in the 1970s.

 

Photo credit: Susan Amrose

In Bangladesh last year, mechanical engineering graduate student Johanna Mathieu saw unmistakable signs of the poisoning afflicting the impoverished country. “Everyone would show us their hands,” says the 26-year-old researcher: the painful and disfiguring sores, blisters and dark spots, all telltale indicators of the deadly toll exacted by arsenic-laced well water.

Mathieu heads a UC Berkeley student team responding to what experts consider the largest mass poisoning in history: millions of Bangladeshis are drinking water containing toxic levels of arsenic. “Between 30 million and 70 million people are exposed,” says Mathieu, who is working with an interdisciplinary group led by Ashok Gadgil, senior scientist at Lawrence Berkeley National Laboratory and adjunct professor in the Energy and Resources Group, to develop a simple, inexpensive process for removing the poison from the water supply.

Waste ash from coal-fired power plants may provide a solution. Gadgil has discovered a method of coating readily available coal ash from India with oxides, hydroxides and oxihydrides of iron. The resulting material—known as ARUBA (arsenic removal using bottom ash) and resembling cocoa powder—binds to the arsenic, then settles out of the water. “We’re trying to find something both technically effective and affordable for people in one of the poorest countries in the world,” Gadgil says.

According to UNICEF, arsenic occurs naturally in the rocks of the region and leaches into the groundwater. It has been found in 1.5 million of the 5 million tube wells tested in Bangladesh. Outside the city of Jessore last year, Mathieu found some village wells with arsenic levels of more than 1,000 parts per billion, 100 times the World Health Organization’s recommended exposure limit. Over a period of 10 to 20 years, such exposure can cause cancer, neurological and cardiovascular problems, hypertension and death.

Mathieu returned to Bangladesh with Gadgil’s team this summer to test a prototype system and explore how it might be introduced. Their vision calls for village-scale treatment facilities capable of delivering clean water to 2,000 people, at an annual cost of $6 to $14 for a household of five, with each individual using two liters of drinking water daily.

Mechanical engineering graduate student Johanna Mathieu (in foreground, bottom photo) tests arsenic levels in Neel Kanda village in the Sonargaon District of Bangladesh as part of a Berkeley effort researching methods to treat the water in affected villages.

 

Photo credit: Tasnuva Khan

 

Many Bangladeshis in affected areas are agricultural laborers who earn just two dollars a day. Partnering with researchers from two Bangladeshi universities, the ARUBA team is assessing the willingness of inhabitants to pay for arsenic-free water. The researchers hope to identify a company to install and operate the systems at an affordable price and expect that it will still be profitable. “We really want to push it out the door to a company that has its heart in the right place,” says Mathieu, a 2004 MIT graduate who previously taught secondary school in Tanzania with the Peace Corps.

Ironically, many of Bangladesh’s wells were installed in the 1970s by relief organizations hoping to halt a deadly epidemic stemming from pathogen-contaminated surface water. The arsenic was discovered in the 1990s.

Scientists say there may be more than one approach to a disaster of such magnitude. Gadgil already invented one system for disinfecting surface water inexpensively with ultraviolet light (which now serves more than one million people daily, through license to a for-profit business) and is investigating an electrochemical process for removing arsenic. The ARUBA project is supported by Berkeley’s Blum Center for Developing Economies and the National Collegiate Inventors and Innovators Alliance.

Go to http://www.youtube.com/watch?v=2R8DfWOGibw for more on the wells in Bangladesh and http://arsenic.lbl.gov for more on the ARUBA project.

By Abby Cohn