Warning: Cadmium, heavy metals collected from moss from Portland trees highly toxic

toxic air

March 3, 2016 – More than three hundred clumps of moss gathered by researchers from trees across Portland looked ordinary, but a profound analysis revealed that the moss contained heavily toxic metals like cadmium.

According to health experts, cadmium can cause kidney malfunction and the deadly disease of cancer. This toxic heavy metal was found particularly in moss samples collected from trees in areas around two glass factories in the city.

health warning sign

Since officials announced the discovery of unhealthy levels of arsenic and cadmium in the air in Southeast Portland earlier this month, they’ve released a lot of new information about airborne heavy metals and the associated public health risks.

The research is another dark spot on the reputation of a city that prides itself on being an environmental example for the rest of the world. It takes pride in having large number of bicycle commuters as well as anti-sprawl development rules. The announcement of the results of the study has caused upheaval of shock, anger and fear.

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The original detection of heavy metals came from a unique study by U.S. Forest Service researchers who gathered hundreds of moss samples from around Portland and tested them for various contaminants. The moss samples flagged two hot spots for cadmium in Southeast Portland and North Portland, as well as some hot spots for lead and nickel that are still being analyzed.

Follow-up air testing by the Oregon Department of Environmental Quality in Southeast Portland found levels of arsenic at 159 times the state benchmark for healthy air and cadmium levels at 49 times higher than the health benchmark.

people very upset

Just last month, Portland residents shouted and even wept in public meetings after a previous study revealed that levels of pollutants in the city air had far surpassed the prescribed limits. They severely criticized city authorities for not knowing what factories were emitting into the air.

DEQ officials linked the pollution they found in Southeast Portland to the Bullseye Glass facility, which uses metals to make colored glass for art and architecture. But they say the nearby rail yard also likely contributed some of the cadmium, which is a component of locomotive exhaust.

Bullseye Glass has stopped using arsenic, cadmium and chromium in its operations and Uroboros Glass has stopped using cadmium and chromium (it hasn’t used arsenic in 20 years). Both companies acted voluntarily; they were operating legally, using those metals in their manufacturing processes as permitted by state and federal laws.


The agency just started testing the air in North Portland on Friday and won’t have results until April. So for now officials only have moss sampling data showing a second cadmium hot spot a quarter-mile from another colored glass-maker, Uroboros Glass.

No one tested the actual emissions from these glass facilities so it is unknown exactly how much of the metals detected in moss and in the air came out of the companies’ furnaces.

Officials say the state’s health benchmarks are very conservative and being exposed to high levels of heavy metals doesn’t mean people will definitely experience health effects. The people at the greatest risk, they say, are those who spent the most time within about a half-mile of the glass factories.

Long term arsenic exposure can cause skin color changes, nerve damage, skin, lung, bladder and liver cancers. Cadmium exposure can cause kidney disease, fragile bones, lung and prostate cancer.

Mary Greeley News