PORTLAND, Ore. (AP) - Scientists using moss to study urban air pollution have released raw data measuring concentrations of metals found in tree moss samples collected throughout Portland.
The U.S. Forest Service's report released Wednesday identified seven out of 346 sites with the highest concentrations of multiple toxic metals in moss samples relative to other samples - that need further study.
The scientists stress that follow-up air quality monitoring is needed to confirm whether metal concentrations found in moss collected from trees are related to concentrations in the air. But they say the data can serve as a screening tool, and citizens, regulators and other scientists can use the information for further study.
The same moss data lead Oregon regulators to test and confirm high levels of cadmium and arsenic around two glass factories in Portland.
The Department of Environmental Quality said Wednesday it would release a statement soon outlining its next steps.