An Innovative Study Uses Moss to Measure Air Toxin Levels at Schools in Portland, Oregon
Mosses and lichens are like sponges, absorbing moisture and nutrients out of the air and from rainfall. In doing so, they also pick up contaminants, which they store in their tissue, making them a living record of pollution levels from the nearby environment. Because they are so widespread, they provide a handy and inexpensive method of sampling air pollutants and mapping pollution sources. The scientists collected moss from 110 K-12 schools across the Portland, Ore., metropolitan area to analyze them for a variety of air pollutants identified as priorities by the U.S. Environmental Protection Agency. One school took the opportunity to engage several third and fifth grade science classes in their study.
The Oregon State Department of Environmental Quality (DEQ) has been following the results of this intensive sampling. The detailed deposition maps based on the collected data show the location and concentration levels of airborne toxins across the Portland area. This has allowed Oregon DEQ to site new permanent air quality monitors as well as several temporary mobile monitors in "trouble spots" showing previously unknown sources of heavy metals.