High lead levels discovered in moss in Portland's older neighborhoods

Oregon State University researchers created a map highlighting the neighborhoods that could be most affected.

PORTLAND, Ore. (KOIN) — Scientists have found elevated lead levels on moss in some of Portland's oldest neighborhoods.

Although U.S. officials have banned multiple lead-based products, the Wall Street Journal reported in 2023 that the element continues to contaminate many parts of the country due to the lead-sheathed telecommunication cables that companies installed from the late 1800s through the 1960s.

As a result of WSJ’s investigation, researchers with Oregon State University and the U.S. Forest Service compared moss samples from Portland neighborhoods that were formed both before and after 1960. They explained that moss is an effective air monitoring system because it covers a wide surface area, and collects the contaminants surrounding it.

According to the study published Tuesday, scientists discovered that moss in areas with lead cables — whether or not the cables are still in use — recorded more than double the lead levels.

They also found that lead levels were more than 38 times higher in the city, compared to rural neighborhoods in the region. In some instances, lead levels were 590 times as high.

Here is a map of the areas that could be the most affected.

Researchers estimate that rainfall has caused the spread of the toxic chemical, which could become airborne if it reaches soil. The team plans to collect soil samples to determine how much it has been contaminated.

Regardless, scientists have determined the detected lead could have health impacts on Portland residents. The Environmental Protection Agency states that babies and young children are especially susceptible to the toxin.

“We were not expecting this result,” OSU Environmental Geochemist Alyssa Shiel, the study’s lead author, said in a statement. “But whether or not these higher levels of lead result in people being exposed depends in part on what people are doing in those places. Right now, we are recommending people avoid interacting with or disturbing soil in those areas where these cables are or were present in the recent past.”

With other long-known sources of lead exposure, including household dust and stained glass, Shiel said testing children for poisoning is a “reasonable course of action” to consider.