Presenter(s) Information

Evelyn A. Haase, Reed CollegeFollow

Start Date

3-7-2022 12:00 AM

End Date

3-8-2022 12:00 AM

Abstract

Protests over the summer of 2020 in support of the Black Lives Matter movement saw a dramatic increase in the use of Riot Control Agents (RCAs), namely tear gas, in response to protestors. Tear gas munitions contain heavy metals, notably zinc (Zn) as a smoke screen agent. Historically, lichens and mosses have been used to assess environmental quality, particularly heavy metal deposition. Lichens and mosses are known bioaccumulators and therefore bioindicators. Air pollution negatively impacts the frequency and density of lichens in urban areas. However, mosses are less sensitive to variation in air quality than lichens. To assess the heavy metal deposition due to the use of RCAs, Parmelia lichens and Polytrichales mosses were collected from street trees at a height minimum of 1.5m using a Teflon coated razor blade. The samples were rinsed, dehydrated, and powderized in preparation for nitric acid-based microwave digestion. Samples were analyzed for Zn concentrations using Flame Atomic Absorption Spectroscopy (FAAS). A map of Zn concentrations in the region of study was compiled using GIS to show any correlation between RCA munition detonation and elevated Zn concentrations.

Subjects

Air quality, Environmental social sciences, GIS / modeling

Persistent Identifier

https://archives.pdx.edu/ds/psu/38027

Rights

© Copyright the author(s)

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Mar 7th, 12:00 AM Mar 8th, 12:00 AM

Heavy metal deposition in epiphytes in downtown Portland, OR in areas of tear gas munitions detonation

Protests over the summer of 2020 in support of the Black Lives Matter movement saw a dramatic increase in the use of Riot Control Agents (RCAs), namely tear gas, in response to protestors. Tear gas munitions contain heavy metals, notably zinc (Zn) as a smoke screen agent. Historically, lichens and mosses have been used to assess environmental quality, particularly heavy metal deposition. Lichens and mosses are known bioaccumulators and therefore bioindicators. Air pollution negatively impacts the frequency and density of lichens in urban areas. However, mosses are less sensitive to variation in air quality than lichens. To assess the heavy metal deposition due to the use of RCAs, Parmelia lichens and Polytrichales mosses were collected from street trees at a height minimum of 1.5m using a Teflon coated razor blade. The samples were rinsed, dehydrated, and powderized in preparation for nitric acid-based microwave digestion. Samples were analyzed for Zn concentrations using Flame Atomic Absorption Spectroscopy (FAAS). A map of Zn concentrations in the region of study was compiled using GIS to show any correlation between RCA munition detonation and elevated Zn concentrations.