September 23, 2002
High concentrations of toxic metals in Bangladesh's drinking water identified by team led by SickKids researcher
TORONTO - Leading an international team of volunteer scientists, Dr. Bibudhendra Sarkar , a senior scientist at The Hospital for Sick Children (SickKids), has identified high concentrations of toxic metals in Bangladesh's drinking water. This research has been published online in September in Articles Online First, for the scientific journal Environmental Health Perspectives.
The team charted national scale maps of the concentrations of arsenic and 29 other toxic metals in Bangladesh's drinking water and found that 60 million people in Bangladesh are drinking water with unsafe levels of arsenic. Similar numbers are exposed to unsafe levels of manganese. The group is the first to evaluate multi-metal synergy in causing severe arsenic toxicity and its health effects in Bangladesh. Chronic arsenic poisoning can cause such conditions as melanosis, leuko-melanosis, keratosis, hyperkeratosis, nonpitting edema, gangrene, and skin cancer.
"On a 1997 trip to Bangladesh, I noticed several children in Bangladesh villages displaying symptoms of arsenic toxicity. It was known at the time that underground drinking water in several districts in Bangladesh was contaminated with arsenic. Our international scientific team is studying the metals present in Bangladesh's drinking water on a national scale and uncovering the extent of the health problem with the country's drinking water supply," said Dr. Sarkar, head of the Structural Biology and Biochemistry Research Program at SickKids and a professor of Biochemistry at the University of Toronto.
Other team members include Dr. Seth Frisbie, an environmental chemist from Better Life Laboratories, Inc., Vermont; Dr. Richard Ortega, an environmental analytical chemist from the University of Bordeaux and Centre National de la Recherche Scientifique, France; and Donald Maynard, an environmental geologist/hydrologist from The Johnson Company Inc., Vermont. The group's work was further facilitated by many supportive research colleagues and organizations in Bangladesh.
Their research has found that metals in Bangladesh's drinking water exceed World Health Organization (WHO) health-based guidelines and include arsenic, a carcinogen; manganese, a known mutagen also associated with neurological damage; lead, a possible carcinogen which causes health problems in humans; nickel, a carcinogen; and chromium, also a human carcinogen. Most samples taken also contained detectable concentrations of antimony, known to magnify arsenic toxicity.
In addition, the team concluded that the severity of chronic arsenic poisoning in Bangladesh might be magnified by a lack of selenium, and a lack of zinc. Selenium is an essential element that prevents the toxic effects of arsenic. Similarly, zinc is an essential element that promotes the repair of tissue damaged by arsenic.
The results of the mapping also suggest that ground water with unsafe levels of arsenic, manganese, lead, nickel and chromium may extend beyond Bangladesh's border into four adjacent and densely populated Indian states.
"It is essential that strategies to supply safe drinking water must be developed and quickly implemented to avoid a catastrophic health crisis in Bangladesh. Our results may allow scientists, policy makers and aid workers to initiate programs to assist the areas most affected by the toxic metals documented by these studies," added Dr. Sarkar, the principal investigator.
The strategic planning for this five-year study was carried out by Dr. Sarkar in Toronto. Fieldwork and collection of water samples were carried out throughout Bangladesh utilizing Global Positioning System (GPS) to pinpoint exact locations of collection. All water samples were flown to France at 0° to 4° for multi-metal analysis. Multi-metal mapping was completed in the US by geostatistical procedures, and data interpreted and prepared for publication in Toronto. Team members gave their time and expertise for free, paid their own expenses, and used facilities of their own institutions to complete the study.
The Hospital for Sick Children, affiliated with the University of Toronto, is the largest paediatric academic health science centre in Canada and one of the largest in the world. Its mission is to provide the best in family-centred, compassionate care, to lead in scientific and clinical advancement, and to prepare the next generation of leaders in child health. For more information, please visit www.sickkids.ca.
For more information, please contact:
Public Affairs
The Hospital for Sick Children
555 University Avenue
Suite 1742, Public Affairs, First floor Atrium
Toronto,
ON
M5G 1X8
Canada
Tel: 416-813-5058
Fax: 416-813-5328