Gathering data is an important step in scientific research. Depending on scientists’ research questions, data might include daily temperatures, the number of insects present in a given area, or a list of tree species growing in a forest. This process may take a large amount of time or cover a huge area.

Some scientists work with other scientists to collect data. And sometimes, scientists work with nonscientists to collect data. Working with nonscientists on a scientific study is known by many different terms, such as civic science, crowdsourcing, or citizen science (figure 1).

Some scientists study the accuracy of data collected by nonscientists. They may also want to know how helping with a study impacts the nonscientists. Studies like the one you are about to read examine whether nonscientists learn more about the research topic, whether they feel more engaged in their own communities, and whether the research helps them feel like they can positively change their communities.

You may have heard the term “environmental justice” in the news, on social media, or in your community. The Environmental Protection Agency (EPA) defines environmental justice as

“the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies”.

To achieve the goal of environmental justice, everyone should have the same degree of protection from environmental and health hazards such as extreme heat, water contamination, or air pollution (figure 2). In addition, everyone should have equal access to the decision-making process to ensure a healthy environment in which to live, learn, and work.

How are scientists involved in environmental justice? The scientists in the study you are about to read suggest that scientists can work with community members to develop research questions that involve both the scientists and the community in order to address environmental justice concerns. Scientists can also involve the community in the setup of the study, the collection of data, and perhaps even the analysis of the data. Additionally, scientists and community members can work together to come up with actions the community can take based on the research findings. These actions could be changes or improvements community members would like to make in their neighborhoods.

Identifying the sources of air pollution is one of the first steps in addressing poor air quality. Some scientists use moss to help find these sources. Moss is a commonly found plant that grows in many different locations, even within cities (figure 4). Because moss does not have roots, it gets water and nutrients from the air. That means that if the air has pollutants in it, such as small amounts of heavy metals, those pollutants are absorbed into the moss along with the water and nutrients.

Scientists collect samples of moss all over the city and measure levels of pollutants in each moss sample. If they find high levels in a certain location, they know an air pollution source is probably nearby. Moss sampling can be used with other air quality monitoring devices to help pinpoint sources of harmful air pollution.

The project in this study was organized by scientists and community leaders to engage students with moss sampling in Seattle. The students involved lived in the areas of the city that were most impacted by air pollution. Scientists wanted to know if the moss samples that students collected and prepared for analysis were as accurate as samples collected and prepared by professional scientists.

They also wanted to know if the project had any impact on students’ environmental knowledge, science career interests, and enjoyment. The scientists asked questions including:

• Did students learn more about moss, moss sampling and preparation methods, air pollution, and urban forestry?
• Did participating in the project make students feel more interested in science and science careers?
• Did students enjoy the project?

The study took place in two neighborhoods, Georgetown and South Park, in south Seattle, Washington (figure 5). These neighborhoods are located near interstate highways, the Port of Seattle, a major rail line, and an airport. Other industrial activities, such as manufacturing and recycling scrap metal and glass, are nearby.

The Duwamish River flows between the two neighborhoods. A 5-mile stretch of the river is designated as a Superfund site because of its contamination by many different hazardous industrial chemicals. Several sources of water and air pollution can be found in and around these two neighborhoods.

The neighborhoods are under-resourced and often have little funding for community improvements. Residents of these neighborhoods may face more health and environmental challenges than residents of other Seattle neighborhoods.

Most of the 26 students involved in the project were residents of Georgetown or South Park and members of a paid 10- week program with the Duwamish Valley Youth Corps. Duwamish Valley Youth Corps promotes mentorship and teamwork for local students, offers experience and training for environmental careers, and engages students in outdoor projects that explore the connection between the natural world and human activity in the Duwamish Valley.

The Youth Corps students in the project were 8th through 12th graders—mostly 8th and 9th grade students—who attended local schools. Because of their participation in the Youth Corps, the students had completed earlier learning modules about environmental science topics and participated in other community activities such as tree planting and river restoration.

The project involved eight sessions during May and June 2019. Participants attended two sessions per week. One of the weekly sessions was a 3-hour weekday afternoon and the other was a 4-hour weekend morning. Two of these sessions were for learning about the project and methods and were held indoors at local community centers. Four sessions were outdoor sampling sessions in Georgetown and South Park. Two sessions were sample preparation sessions at a high school science lab. At least four adults, either scientists or community leaders, worked with student participants at each session

On sample collection days, student participants worked in small groups of three to five to collect moss. Scientists divided the study area into a grid of 250-meter by 250-meter squares. Each student group was assigned certain squares on the grid to collect their samples. Students used a map app on smartphones to navigate to the center of their assigned squares (figure 6).

They identified a tree closest to the center of the grid square and looked for a specific species of moss, Lyell’s bristle moss, on that tree. The sample they collected was known as the primary student sample. If there was no moss on that tree, students moved to the next closest tree. If there was no moss in the grid square, or if conditions around a tree with moss did not allow access to collect a sample, students moved on to their next assigned grid square.

Students collected a second sample of moss, called a replicate sample, in some of the grid squares. The scientists compared these replicate samples to the primary samples to find out if the metal concentrations were the same in each sample. This comparison showed whether the students’ sampling and preparation methods were precise and reliable.

Expert scientists who had been involved in similar studies resampled some of the grid squares after students had collected their samples. Most of the experts collected their samples 12 days after students collected their samples. Scientists compared their samples to the students’ primary samples to see if both samples recorded the same levels of metal concentrations (figure 7). This comparison showed whether the students’ samples were accurate.

Once the moss samples were collected, student participants prepared their moss samples in a high school science lab over the course of two sessions (figure 8). They wore gloves and cleaned their workspaces and tools before and after working with each sample. To prepare each sample, students harvested the upper two-thirds of living moss stems and used forceps to remove other debris. Samples had to weigh at least 1.5 grams. The expert scientists prepared their samples using the same method.

All moss samples were mailed to an analytical chemistry lab to determine the concentrations of 25 elements in each sample. Scientists focused on six of these elements—heavy metals that are commonly associated with negative human health and environmental effects:

• arsenic (As)
• cadmium (Cd)
• cobalt (Co)
• chromium (Cr)
• nickel (Ni)
• lead (Pb).

When the scientists received the results from the chemistry lab, they compared heavy metal concentrations in the primary student samples to the replicate student samples. They also compared the primary student samples to the expert samples.

To find out how the project affected the student participants, the scientists asked the students to complete surveys on 4 days of the project. These surveys had a combination of test-style questions and survey-style questions. The test-style questions had right or wrong answers and asked about moss, urban forestry, moss sampling methods, and moss sample preparation. Survey-style questions were open-ended and asked for students’ opinions about their academic and career interests and what students liked and disliked about the project.

Test-style questions about the project content were given before and after that particular project content was taught. The survey-style questions about the students’ career interests were given both before and after the project as a whole. The question about their favorite academic subjects was only asked at the beginning of the project, and the question about what they thought about the project was only given at the end of the project.

The final collection of moss samples included 79 student samples, including some replicate samples, from 61 different locations. In general, heavy metal concentrations in the students’ primary moss samples were similar to their replicate samples. The similarity between primary and replicate student moss samples shows that their sample collection and preparation methods were precise and repeatable.

There was a difference in heavy metal concentrations between the students’ primary moss samples and the experts’ samples. The student samples tended to show higher concentrations of the six heavy metals than the expert scientists’ samples did. However, these differences were not always statistically significant.

When scientists analyzed the results of the test and survey questions, they found that student participants improved on all subject matter questions over the course of the project. The nine students who took pre- and post-tests improved significantly on questions about moss, air pollution, urban forestry, and moss sample preparation.

Overall, responses to the project were favorable. Most of the students said they liked the project, and only one student said they disliked the project a little. Student participants were also asked open-ended questions about what they liked and did not like about the project (table 1).

Overall, the metal concentrations measured in the student samples were precise because their primary samples generally matched their replicate samples. The comparison between student-collected and expert-collected samples was less clear. The scientists think the differences between student and expert samples may have been caused by other conditions that are not understood yet. For example, because most of the expert samples were taken 12 days after the student samples, weather conditions like rain may have influenced metal concentration levels.

Other civic science projects have avoided having nonexperts, like students, prepare samples for analysis. However, the scientists in this study found that with proper training, guidance, and the correct environment (such as a lab), nonexperts like these students can be successful at sample collection and preparation (figure 9).

Because the project took place during the global coronavirus (COVID-19) pandemic, there were significant delays in receiving the metal concentration results from the chemistry lab. Despite the delay, 18 of the students attended an event to share the data from their work over a year after their participation in the project (figure 10).

The scientists and community organizers hope that with faster data analysis, they can involve students in more phases of the project in the future, including interpreting results and sharing that information with their communities as well as planning and participating in future actions based on the data. They hope that this involvement will increase student interest and enthusiasm and encourage more consistent participation in future projects.

The study also demonstrated that the students learned project content and were generally positive about their experiences, but their career interests did not change. Because this project was part of a pilot program, this information will help the scientists and community leaders make changes and improvements to the next project (table 2).

The scientists suggest that community-driven civic science may be an important tool for encouraging youth involvement in environmental research in cities. The scientists and community organizers are hopeful that projects like these will support environmental education, give students tools to learn about their environment, and encourage actions to improve those environments (figure 11). These students, as well as other community members, are an important part of environmental justice efforts in the Duwamish River Valley community.

Adapted from Derrien, M.M.; Zuidema, C.; Jovan, S.; Bidwell, A.; Brinkley, W.; López, P.; Barnhill, R.; Blahna, D.J. 2020. Toward environmental justice in civic science: youth performance and experience measuring air pollution using moss as a bio-indicator in industrial-adjacent neighborhoods. International Journal of Environmental Research and Public Health. 17(19): 7278.