Ask the moss about heavy metals

Surrounded by atmospheric scientists at work, I imagine this type of equipment for air quality monitoring:

Link to original image on wikimedia commons.
An air quality monitoring station. Photo from wikipedia.
Link to original image on Flickr
Air pollutant monitoring equipment by Barnaby Smith / Centre for Ecology & Hydrology on Flickr

but apparently, moss like these –

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Sphagnum moss. Photo from wikipedia.

are inexpensive and efficient tools for monitoring heavy metals in the atmosphere.

People have known for a while that moss are able to absorb these pollutants. Norway has a cool map of heavy metal concentrations and the changes over the past 40 years, all using moss as a source of data. See the map of lead, for example.

Plants with roots take up nutrients from the soil, but moss lack roots and instead absorb their nutrients directly from the air moisture. Moss also lack a continuous protective cuticle layer that makes moss tissue more permeable to gas exchange. This makes them better indicators of air pollutants. Continue reading