April 6, 2016. Moss growing on urban trees is a useful bio-indicator of cadmium air pollution in Portland, Oregon, a U.S. Forest Service Pacific Northwest Research Station-led study has found. The work - the first to use moss to generate a rigorous and detailed map of air pollution in a U.S. city - is published online in the journal Science of the Total Environment.
"What's unique about this study is that we used moss to track down previously unknown pollution sources in a complex urban environment with many possible sources," said Sarah Jovan, a research lichenologist at the station based in Portland and one of the study's co-leads.
Moss have been used as bioindicators - living organisms that can help monitor environmental health - by the Forest Service and other agencies for decades. Because moss lack roots, they absorb all of their water and nutrients from the atmosphere, inadvertently taking up and storing whatever compounds happen to be in the air.