Arsenic in the park and phytoremediation

When the U.S Geological Survey geographer Terry Slonecker was going through aerial photographs, he could easily detect the stress and stunted growth of trees and grass in the park in Washington that led him to conclude its arsenic. He was in fact looking for arsenic in a nearby area used for military activities in World War I. But the park has no history of WWI activities rather it goes back to the American Civil War which occurred between 1861 to 1865. But how it could leave arsenic there?

During the civil war soldiers remains were protected from decomposition by using embalming fluids, and as arsenic was inexpensive, therefore it was a common ingredient of the compound (arsenic is a poisonous chemical element).  Embalming fluid is a chemical that contains formaldehyde (now replacing arsenic), methanol, ethanol and other solvents and is used to preserve the deceased from being decomposed by bacteria or other microorganisms. 

But American Civil War took place almost 150 years before and as it is a park, so plants played their beneficial roles. They exploited arsenic from the ground therefore suffered from growth stress. It’s phytoremediation, and as it’s a long time therefore, may be plants and grasses have already extracted much of the arsenic from the ground. Investigations on the plants content of arsenic in their above-ground parts should be carried out as well. May be it can also give a clue of a new hyperaccumulator plants for arsenic. Currently Chinese Brake Fern (Pteris vittata) is well established hyperaccumulator for arsenic (that means the plant can take as much as 100 times more arsenic in its above-ground part than its concentration in soil). 

Currently no data is available on arsenic concentration as it is in lab. Soon we will know more.

News Source: L.A. Times