Washington State Department of Ecology

Publication Summary

Title

American Plating Post-Interim-Action Groundwater Monitoring Results, May and September, 2006

Month-Year Published

February 2007

Online Availability

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Short Description

Groundwater samples for dissolved metals and WAD cyanide were collected in May and September 2006 from the former American Plating site in Tacoma to provide post-interim-action groundwater data.

Dissolved cadmium, copper, and nickel were detected in the groundwater, but at concentrations below the cleanup standards. Dissolved chromium concentrations ranged from 16 to 104 ug/L. Hexavalent chromium was not detected in any of the wells. Well MW-10, which has had the highest nickel concentrations (29 to 62 ug/L), was damaged and could not be sampled.

WAD cyanide exceeded the cleanup standard of 1 ug/L in one well at concentrations of 5 and 8 ug/L.

(Also see abstract below)

Publication Number

07-03-005

Author(s)

Marti, P.

Print Availability

Request from the program.

Number of pages

16 + app (21 total)

Keywords

cleanup, groundwater, monitoring, results, samples, toxics, toxics cleanup, water, wells

Subject Waterbodies

Thea Foss

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Abstract

Long Description

During May and September, 2006, groundwater samples were collected from four monitoring wells at the former American Plating site located on the Thea Foss Waterway in Tacoma, Washington. Samples were analyzed for dissolved metals (cadmium, chromium, hexavalent chromium, copper, and nickel) and weak acid dissociable (WAD) cyanide. Results provided the Department of Ecology′s Toxics Cleanup Program with post-interim-action groundwater monitoring data.

Dissolved cadmium, chromium, copper, and nickel, as well as WAD cyanide, were detected in groundwater at the site during May and September.

Dissolved chromium was detected in all four wells. In May, chromium concentrations ranged from 30 to 104 ug/L, decreasing in September to a range of 16 to 41 ug/L. Dissolved hexavalent chromium was not detected in any of the samples. Therefore, it is assumed that the less toxic and less mobile trivalent chromium was present.

Dissolved nickel was detected in all four wells with concentrations ranging from 1 to 3.8 ug/L which is below the groundwater cleanup standard of 8.2 ug/L. Nickel concentrations had exceeded the cleanup standard in wells MW-5 and MW-10 in 2004/2005.

Dissolved cadmium and copper were detected in the sampled wells, but at concentrations below the cleanup standards.

WAD cyanide was detected in well MW-4 at concentrations of 5 and 8 ug/L which exceeds the cleanup standard of 1 ug/L. This is the first detection of WAD cyanide since Ecology began monitoring in 2004.

Well MW-10, which has been part of the monitoring program since February 2004, was damaged during 2006 and should be decommissioned. Since elevated dissolved nickel concentrations (29 to 62 ug/L) and low concentrations of some volatile organics have been detected in this well, installation of a new well should be considered if monitoring is to continue at the American Plating site.

Link to EIM data for User Study ID AMERPLAT

This page last updated November 6, 2009