PORTLAND, Ore. April 6, 2016. Moss growing on urban trees is a useful bio-indicator of cadmium air pollution in Portland, Oregon, a U.S. Forest Service Pacific Northwest Research Station-led study has found. The work—the first to use moss to generate a rigorous and detailed map of air pollution in a U.S. city—is published online in the journal Science of the Total Environment.
“What’s unique about this stud*y is that we used moss to track down previously unknown pollution sources in a complex urban environment with many possible sources,” said Sarah Jovan, a research lichenologist at the station based in Portland and one of the study’s co-leads.
Moss have been used as bioindicators—living organisms that can help monitor environmental health—by the Forest Service and other agencies for decades. Because moss lack roots, they absorb all of their water and nutrients from the atmosphere, inadvertently taking up and storing whatever compounds happen to be in the air.
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Initially, the science team was concerned with air pollution from polycyclic aromatic hydrocarbons, a class of potent environmental toxins emitted by the burning of fossil fuels and wood. The scientists added in heavy metals because the laboratory analysis was relatively inexpensive. One heavy metal in particular, cadmium, was also a top concern of the Oregon Department of Environmental Quality (DEQ) because a 2011 DEQ study found discrepancies between predicted and observed concentrations of the metal at Portland’s one permanent air-quality monitoring site. Cadmium, which is used primarily in nickel-cadmium battery manufacturing, electroplating, and stained-glass production, is linked to health problems such as kidney disease and cancer.
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https://www.blogger.com/blogger.g?blogID=11479099#editor/target=post;postID=1981059571028560346
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"The nickel plume stretches north of Precision Castparts, an industrial manufacturer that has been called one of the country's top polluters. Federal records show the company released 158 pounds of nickel to the air in 2014.
Jay Khetani, a Precision Castparts spokesman, said almost all of the nickel the company uses is in low-toxicity alloyed forms. He said the company looks forward to reviewing the tree moss data.
"We do use nickel," he said, "but cannot of course establish a linkage to the tree moss data."
The lead concentration is centered on a residential tract across the road from a string of industrial sites on North Columbia Boulevard.
The health implications aren't clear. The maps only show concentrations of metals found in moss. The state Department of Environmental Quality said testing of soil and air in each neighborhood would be needed to establish the level of health risk for residents, and no such testing has occurred.
Lead is a potent neurotoxin that can cause miscarriages, developmental problems in young children and irreversible brain damage. Nickel can cause asthma and lung cancer.
NOW THE FUNNY PART:
"A Department of Environmental Quality spokeswoman downplayed the maps' significance, saying they don't prove Portlanders nearby are breathing dirty air.
"Just because the moss maps show a hot spot doesn't mean it's that hot or relevant — it's just showing the highest value in the moss dataset," said Jennifer Flynt, an agency spokeswoman."
http://www.oregonlive.com/environment/index.ssf/2016/02/new_maps_show_heavy_metal_hot.html
