title: Using an epiphytic moss to identify previously unknown sources of atmospheric cadmium pollution.
abstract: Urban networks of air-quality monitors are often too widely spaced to identify sources of air pollutants, especially if they do not disperse far from emission sources. The objectives of this study were to test the use of moss bio-indicators to develop a fine-scale map of atmospherically-derived cadmium and to identify the sources of cadmium in a complex urban setting. We collected 346 samples of the moss Orthotrichum lyellii from deciduous trees in December, 2013 using a modified randomized grid-based sampling strategy across Portland, Oregon. We estimated a spatial linear model of moss cadmium levels and predicted cadmium on a 50m grid across the city. Cadmium levels in moss were positively correlated with proximity to two stained-glass manufacturers, proximity to the Oregon-Washington border, and percent industrial land in a 500m buffer, and negatively correlated with percent residential land in a 500m buffer. The maps showed very high concentrations of cadmium around the two stained-glass manufacturers, neither of which were known to environmental regulators as cadmium emitters. In addition, in response to our findings, the Oregon Department of Environmental Quality placed an instrumental monitor 120m from the larger stained-glass manufacturer in October, 2015. The monthly average atmospheric cadmium concentration was 29.4ng/m(3), which is 49 times higher than Oregon's benchmark of 0.6ng/m(3), and high enough to pose a health risk from even short-term exposure. Both stained-glass manufacturers voluntarily stopped using cadmium after the monitoring results were made public, and the monthly average cadmium levels precipitously dropped to 1.1ng/m(3) for stained-glass manufacturer #1 and 0.67ng/m(3) for stained-glass manufacturer #2.
authors.affiliation: USDA Forest Service, PNW Research Station, 620 SW Main, Suite 400, Portland, OR 97205, USA. Electronic address: gdonovan@fs.fed.us.
authors.forename: Geoffrey H
authors.initials: GH
authors.lastname: Donovan
authors.affiliation: USDA Forest Service, PNW Research Station, 620 SW Main, Suite 400, Portland, OR 97205, USA. Electronic address: sjovan@fs.fed.us.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Jovan
authors.affiliation: USDA Forest Service, PNW Research Station, 620 SW Main, Suite 400, Portland, OR 97205, USA. Electronic address: dgatziolis@fs.fed.us.
authors.forename: Demetrios
authors.initials: D
authors.lastname: Gatziolis
authors.affiliation: Dornsife School of Public Health, Drexel University, Nesbitt Hall, 3215 Market St, Philadelphia, PA 19104, USA. Electronic address: igor.burstyn@drexel.edu.
authors.forename: Igor
authors.initials: I
authors.lastname: Burstyn
authors.affiliation: Dornsife School of Public Health, Drexel University, Nesbitt Hall, 3215 Market St, Philadelphia, PA 19104, USA. Electronic address: ylm23@drexel.edu.
authors.forename: Yvonne L
authors.initials: YL
authors.lastname: Michael
authors.affiliation: USDA Forest Service, Logan Forest Sciences Laboratory, 860 North 1200 East, Logan, UT 84321. Electronic address: mcamacher1@outlook.com.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Amacher
authors.affiliation: USDA Forest Service, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, USA. Electronic address: vjmonleon@fs.fed.us.
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Monleon
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D044002:Bryophyta / Q000737:chemistry*; D002104:Cadmium / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D009922:Oregon
chemical_list: D000393:Air Pollutants; D002104:Cadmium
keywords: Air pollution; Arsenic; Orthotrichum lyellii; Selenium; Stained-glass