Arsenic in Well Water - Geochemistry
You may be aware of the problems caused by arsenic in well water in Bangladesh. In order to provide communities in Bangladesh with water that was free from disease causing organisms, numerous international aid and government agencies drilled water wells to supply "safe" drinking water. What they were unaware of is that arsenic occurs naturally at trace levels in minerals in the geological formations where the wells were drilled. Arsenic in the water from those wells has a high enough concentration to cause health effects if ingested over an extended time. A heroic attempt to eliminate health problems in Bangladesh resulted in a different major health problem.
On the other hand, you may not be aware of the fact that there are many locations in the United States where well water has arsenic levels above the safe limits prescribed by the World Health Organization (WHO). Geochemists can help in understanding and dealing with the problems of trace toxic elements in well water in a number of ways:
- Concentration determination and compilation of GIS databases on well water concentrations
- Determination of the source of the elements. Is the source anthropogenic (due to the activities of mankind) or is it geological (present in the minerals present in the area)
- Determine the mechanisms for dissolution and transport of the element into the wells
- Study the chemical forms or species that the element occurs in. Some chemical species of an element can be more toxic than others or might be more soluble in water and therefore transported more effectively. This field of study is known as speciation.
From ChemPRIME: 1.1: What Chemists Do