Event Title

Biomonitoring of Ramalina farinacea lichens deployed in Seattle, Washington via sequential extraction of metals

Co-Author(s)

Gunnar Guddal

Research Mentor(s)

Ruth Sofield

Description

To evaluate the heterogeneity of metal accumulation in lichens exposed to varying amounts of industrial pollution in the field, a sequential extraction was performed on Ramalina farinacea lichens deployed at nine locations in Seattle, Washington. Lichens were initially collected from the Sehome Arboretum in Bellingham, Washington and then suspended in nylon bags for two and then twelve weeks to pick up airborne metals. After the exposure periods, EDTA was used as a chelating agent in a sequential extraction to analyze the varying amounts and ratios of water soluble non-bound metals, extracellular metals, and intracellular metals. Lichen samples were then digested and analyzed to quantify residual particulate metals. Metals in the extracellular fraction are thought to be indicators of recent atmospheric metal deposition, while metals in the intracellular and residual fractions indicate long term metal deposition and integration into the lichen thalli. Differences in fractionation and amounts of accumulated metals serve as an indicator of amount and timing of metal pollution at the different exposure sites, supporting lichen biomonitoring as an effective way to characterize metal pollution. Results collected to date will be presented.

Document Type

Event

Start Date

16-5-2018 9:00 AM

End Date

16-5-2018 12:00 PM

Location

Environmental Sciences

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

Language

English

Format

application/pdf

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May 16th, 9:00 AM May 16th, 12:00 PM

Biomonitoring of Ramalina farinacea lichens deployed in Seattle, Washington via sequential extraction of metals

Environmental Sciences

To evaluate the heterogeneity of metal accumulation in lichens exposed to varying amounts of industrial pollution in the field, a sequential extraction was performed on Ramalina farinacea lichens deployed at nine locations in Seattle, Washington. Lichens were initially collected from the Sehome Arboretum in Bellingham, Washington and then suspended in nylon bags for two and then twelve weeks to pick up airborne metals. After the exposure periods, EDTA was used as a chelating agent in a sequential extraction to analyze the varying amounts and ratios of water soluble non-bound metals, extracellular metals, and intracellular metals. Lichen samples were then digested and analyzed to quantify residual particulate metals. Metals in the extracellular fraction are thought to be indicators of recent atmospheric metal deposition, while metals in the intracellular and residual fractions indicate long term metal deposition and integration into the lichen thalli. Differences in fractionation and amounts of accumulated metals serve as an indicator of amount and timing of metal pollution at the different exposure sites, supporting lichen biomonitoring as an effective way to characterize metal pollution. Results collected to date will be presented.