Currently, U.S. government officials, and scientific opinion, is uncertain as to whether the organisms are damaging the Jefferson Memorial, or even if they can be eradicated without damaging the important landmark.
The Thomas Jefferson Memorial is a presidential memorial in Washington, D.C., dedicated to Thomas Jefferson (1743–1826). The neoclassical style Memorial building is located on the Tidal Basin off the Washington Channel of the Potomac River. The structure was designed by the architect John Russell Pope, and completed in 1943. A bronze statue of Jefferson was added in 1947, bringing to total weight to 32,000-tons.
According to Sky News, a blackish biofilm became noticeable a decade ago and it has increasingly become worse. Interviewing National Mall and Memorial Parks spokesperson Catherine Dewey, Sky News quotes the spokesperson saying: “the biofilm has grown immensely in recent years.”
A biofilm, Pharmaceutical Microbiology states, is any group of microorganisms in which cells stick to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS). Once a biofilm has formed, it constitutes a micro-niche that provides bacteria with an environment that is highly conducive to their survival while also protecting them from various types of aggression from outside.
The Park Service are trying out different cleaning solutions to remove the bacteria. There need to be careful in selecting the correct cleaning materials as not to damage the structure. Even if this proves successful, given that it there’s no known reason why the microbial film developed there is a risk that it will re-occur.