20 June 2010

A Tragic Ignorance of Mineral Weathering

Posted by John Freeland

Rainwater harvesting offers a safe alternative to arsenic-tainted groundwater.

Following up on a report from the British journal Lancet, global news agency AFP reports:

“Up to 77 million Bangladeshis have been exposed to toxic levels of arsenic from contaminated drinking water, and even low-level exposure to the poison is not risk-free, The Lancet medical journal reported.

Over the past decade, more than 20 percent of deaths recorded in a study that monitored nearly 12,000 people in the Araihazar district of the capital Dhaka appear to have been caused by arsenic-tainted well water.

By some estimates, between 35 and 77 million people in Bangladesh have been chronically exposed to arsenic-contaminated water as a result of a catastrophically misguided campaign in the 1970s.”

The “misguided campaign” had the good intention of providing safe water to millions of people living on the vast, low-lying Ganges–Brahmaputra River Delta. The delta receives drainage and sediment from the Himalayan mountains and, due to the wet tropical climate and relative solubility of arsenic-containing soil minerals, the groundwater is contaminated.

Rainwater harvesting is an inexpensive, sustainable alternative to using tainted groundwater for drinking. Expanded use of rainwater harvesting with simple technological enhancements to improve on an ancient practice is showing good results. The problem seems to be difficulty expanding the program fast enough.

Bangladesh, squeezed between the mountains and the sea, and most of which is less than 40-feet above sea level, has the coastal problem of saltwater intrusion into surface freshwater sources. Here is an interesting video on that topic and efforts to build more rainwater harvesting systems.

Further information on Rainwater Harvesting