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Seattle students study heavy metals with the Forest Service

Connie Ho
USDA Natural Resources and Environment
May 5, 2022

A picture of a large, green moss bunch in a palm of a person's hand.
The moss Orthotrichum lyellii. Because moss doesn’t have roots. it absorbs nutrients – and pollution – through moisture in the air. Students in Seattle, Washington used moss as a screening tool to identify sites with high pollution levels. (USDA Forest Service photo by Sarah Jovan)

Air is a critical resource for many living things, including people. USDA Forest Service scientists explore the effects of air pollution on environmental and human health – and how those effects impact different communities disproportionately.

These variations led Monika Derrien, a research social scientist with the Forest Service Pacific Northwest Research Station, to ask “How can we create opportunities for young people to meaningfully investigate and address environmental injustices in their communities?”

To answer the question, Derrien worked with her PNW colleague Research Ecologist Sarah Jovan and local leaders to create a community science project. Local youth corps members studied how heavy metal pollution may be affecting air quality in two industrial-adjacent neighborhoods in Seattle, Washington.

Forest Service scientists and students with the Duwamish River Community Coalition made their observations in a somewhat unusual way—by studying moss.

An earlier Portland-based study showed that moss could be used as a screening tool to identify sites in cities with high pollution levels. Because moss doesn’t have roots, it absorbs nutrients – and pollution – through moisture in the air.

A picture of two individuals standing near a tree.
A Duwamish Valley Youth Corps member considers a tree for moss sampling with Pacific Northwest Research Station emeritus scientist Dale Blahna. (USDA Forest Service photo by Monika Derrien)

These pollutants are an issue close to home for many of the students. Ranging from 8th to 12th grade, many identified as people of color, and most lived in urban neighborhoods near industrial areas with heightened exposure to air pollution.

Informed by past research, the students collected moss growing on street trees, noting the location of each sample. They returned to the lab to weigh each selection before handing it over to a Forest Service analytical chemistry lab in Grand Rapids, Minnesota. This lab has extensive experience in moss analysis techniques. Scientists measured the amount of pollutant in each sample, noting the presence of heavy metals such as arsenic, chromium and lead, all of which are harmful to human health.

“We looked at this as an ideal case to attempt a moss study using community science due to the long history of collaboration among nonprofits, universities, and government entities interested in local pollution issues,” said Jovan.

A picture of a student standing near an urban tree, growing between a city street and a sidewalk.
A Duwamish Valley Youth Corps member holds up a moss sample next to the tree where it was collected. (USDA Forest Service photo by Monika Derrien)

The Duwamish River Community Coalition, which participated in the project, is focused on promoting experience and training for environmental careers among youth, who are encouraged to explore topics such as urban forestry, green infrastructure and environmental justice. Throughout the moss study, not only were the students’ critical thinking and problem-solving skills sharpened, but their understanding of grassroots advocacy also increased.

Youth corps members who participated in the project completed surveys to gauge their interest and experience working with the moss. The results showed that there was an increase in participant interest in areas like health care and medicine, and students enjoyed working in the outdoors with the moss samples. The insights from the project will be useful for the future development of similar projects and evaluations of experiences with youth scientists.

“This opened my eyes more and showed me that we as humans need to help even if it’s just learning about moss and how it catches the pollution around,” said a 15-year-old student participant. “But my biggest takeaway from the program was to tell my friends and family about taking care of our earth and making it a better sustainable environment.”

The project was supported by the Green-Duwamish Learning Landscape, a collaborative group consisting of community organizations, government agencies, and university researchers, among others who have a vested interest in the watershed of the Green-Duwamish River.

Derrien and Jovan believe that the pilot program demonstrates the value of community science in engaging younger generations in environmental justice and health issues, and that many projects like it could be implemented across the country to engage youth in environmental science for the betterment of the health of the environment, their communities, and themselves.