Of moss and men: Using moss as a bioindicator of toxic heavy metals at the city scale

Abstract

Air quality is a critical issue affecting the health of billions of people worldwide, yet often little is known about what is in the air we breathe. To reduce air pollution’s health impacts, pollution sources must first be reliably identified. Otherwise, it is impossible to design and effectively enforce environmental standards. However, urban networks of air quality monitors are often too widely spaced to identify the sources of air pollutants, especially for pollutants that do not disperse far from their sources. Developing high-resolution pollution maps with data from these widely spaced monitors is problematic.

In a recent study, scientists with the U.S. Forest Service Pacific Northwest Research Station tested a common tree moss for the presence of heavy metals at 346 locations in Portland, Oregon. The study yielded fine-scale maps showing air pollution distribution across the city at a level of spatial detail that had never been seen. The maps revealed two sources of cadmium that were emitting levels of pollutants many times higher than state health benchmarks. The Portland moss study raised awareness of heavy metal pollution and the inadequacy of current air monitoring networks for detecting toxic emissions.

Keywords

Moss, Portland, air quality, cadmium.

Citation

Vizcarra, Natasha; Jovan, Sarah. 2018. Of moss and men: Using moss as a bioindicator of toxic heavy metals at the city scale. Science Findings 205. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.