Presentation Abstract

As part of an ambient monitoring program being conducted for the Puget Sound Naval Shipyard & Intermediate Maintenance Facility in Sinclair and Dyes Inlets of the Puget Sound, receiving waters of the Inlets are routinely monitored for trace metals and toxicity to assess water quality status, track progress in achieving water quality goals, and demonstrate protection of aquatic life. Recently, aqueous metal bioavailability using diffusive gradient thin-film (DGT) passive samplers has been incorporated into the monitoring program. The DGT samplers allow for the measurement of trace metal concentrations integrated over time via in situ chelation of labile metals. The DGT samplers are selective for free and weakly complexed metal species, allowing uptake to mimic diffusion limited bioavailability. This provides a monitoring solution by which episodic events are captured that provides a better representation of the potential for biological effects. A combination of laboratory performance tests and field deployed DGTs have been used to assess the reliability of the method to accurately measure labile concentrations Cu, Pb, and Zn under baseline and episodic storm events. Based on the results from DGTs deployed over different intervals spanning continuous deployments of 1-56 days and rainfall events of 0.4 – 3.2 inches/24 hr, reproducibility was affected by the presence of partially labile complexes, mass loading rate (time to equilibrium) which is proportional to free ion concentration, and variation in resin blank values. Best results were obtained for 3-7 day DGT deployments which showed high resolution of labile metal concentrations over varying spatial and temporal scales. The ability to conduct constant surveillance of metal bioavailable for a variety of freshwater and nearshore marine environments under varying environmental conditions greatly improves the assessment of potential ecological effects from exposure to metals.

Session Title

Posters: Habitat Restoration & Protection

Keywords

DGT, seawater, passive sampler

Conference Track

SSE18: Posters

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE18-68

Start Date

5-4-2018 11:30 AM

End Date

5-4-2018 1:30 PM

Type of Presentation

Poster

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 5th, 11:30 AM Apr 5th, 1:30 PM

Diffusive gradient thin-films in seawater: time integrated technique for aqueous trace metal monitoring in impacted waterways

As part of an ambient monitoring program being conducted for the Puget Sound Naval Shipyard & Intermediate Maintenance Facility in Sinclair and Dyes Inlets of the Puget Sound, receiving waters of the Inlets are routinely monitored for trace metals and toxicity to assess water quality status, track progress in achieving water quality goals, and demonstrate protection of aquatic life. Recently, aqueous metal bioavailability using diffusive gradient thin-film (DGT) passive samplers has been incorporated into the monitoring program. The DGT samplers allow for the measurement of trace metal concentrations integrated over time via in situ chelation of labile metals. The DGT samplers are selective for free and weakly complexed metal species, allowing uptake to mimic diffusion limited bioavailability. This provides a monitoring solution by which episodic events are captured that provides a better representation of the potential for biological effects. A combination of laboratory performance tests and field deployed DGTs have been used to assess the reliability of the method to accurately measure labile concentrations Cu, Pb, and Zn under baseline and episodic storm events. Based on the results from DGTs deployed over different intervals spanning continuous deployments of 1-56 days and rainfall events of 0.4 – 3.2 inches/24 hr, reproducibility was affected by the presence of partially labile complexes, mass loading rate (time to equilibrium) which is proportional to free ion concentration, and variation in resin blank values. Best results were obtained for 3-7 day DGT deployments which showed high resolution of labile metal concentrations over varying spatial and temporal scales. The ability to conduct constant surveillance of metal bioavailable for a variety of freshwater and nearshore marine environments under varying environmental conditions greatly improves the assessment of potential ecological effects from exposure to metals.