terra central

A Tragic Ignorance of Mineral Weathering

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.

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

Coast of Alaska: Accelerated Erosion 2002-2007

Alaskan coastal erosion (USGS).

A five-year study in Alaska led by the U.S. Geological Survey (USGS) found that shoreline erosion along a 40-mile stretch of the Beaufort Sea has been accelerating from about 20-feet per year fifty years ago, to 45-feet per year by 2007. The research makes obvious the importance of considering the specific properties of the earthen materials exposed to erosive forces. In this case, the land contains permafrost, a consituent of the soil order called Gelisol.

An excerpt:

The authors proposed that these recent shifts in the rate and pattern of land loss along this coastline segment are potentially a result of changing arctic conditions, including declining sea ice extent, increasing summertime sea-surface temperature, rising sea level, and increases in storm power and corresponding wave action.

“Taken together, these factors may be leading to a new era in ocean-land interactions that seem to be repositioning and reshaping the Arctic coastline,” wrote (Benjamin) Jones and his colleagues. “And any increases in the current rates of coastal retreat will have further ramifications on Arctic landscapes – including losses in freshwater and terrestrial wildlife habitats, and in disappearing cultural sites, as well as adversely impacting coastal villages and towns. In addition, oil test wells are threatened.”

Alaskan permafrost erosion (USGS)

For most of us who live on the relative “terra firma” of the mid-latitude continents, global warming may seem like a fairly benign process, one that might result in better weather to play golf. The Arctic and Antarctic environments, by contrast, are very different, very fragile worlds. The authors are careful with their words, using the standard qualifiers, but it’s pretty clear they think climate change is a factor as the waves pound that coast.

Research Paper:
Jones, B.M., Arp, C.D., Jorgenson, M.T., Hinkel, K.M., Schmutz, J.A., and Flint, P.L. Increase in the rate and uniformity of coastline erosion in arctic Alaska. Geophysical Research Letters, February 14, 2009. http://www.agu.org/journals/gl/gl0903/2008GL036205/.

Photos source: USGS