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Environmental Cleanup Site Information (ECSI) Database Site Summary Report - Details for Site ID 2409, Ross Island (River Mile 15.4)

This report shows data entered as of December 7, 2023 at 11:18:18 AM

This report contains site details, organized into the following sections: 1) Site Photos (appears only if the site has photos); 2) General Site Information; 3) Site Characteristics; 4) Substance Contamination Information; 5) Investigative, Remedial and Administrative Actions; and 6) Site Environmental Controls (i.e., institutional or engineering controls; appears only if DEQ has applied one or more such controls to the site).  A key to certain acronyms and terms used in the report appears at the bottom of the page.

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Environmental Cleanup Site Information (ECSI) Database Site Summary Report - Details for Site ID 2409, Ross Island (River Mile 15.4)

General Site Information

Site ID: 2409 Site Name: Ross Island (River Mile 15.4) CERCLIS No:
Address: Within the interior of Ross Island, in Willamette River Portland 97202
  County: Multnomah Region: Northwest
Other location information: Willamette River - River Mile 15.
Investigation Status: Listed on CRL or Inventory
Brownfield Site: No NPL Site: No Orphan Site: No Study Area: No
Property: Twnshp/Range/Sect: 1S , 1E , 14 Tax Lots: 37, 111,200
  Latitude: 45.4844 deg. Longitude: -122.6597 deg.  Site Size: 84.18 acres
Other Site Names:
  Ross Island Sand and Gravel

Site Characteristics

General Site Description:
Site History: Ross Island Sand and Gravel is a major supplier of aggregate in the Portland area. From the 1920s until the summer of 2001, the company mined and processed sand and gravel from the Willamette River at this site.
Contamination Information: Ross Island Sand and Gravel began importing fill material in the early 1980s. Some of the material the company obtained from Port of Portland shipyards was determined to be unsuitable for unconfined open water disposal due to the presence of contaminants. This material was placed lawfully in depressions within the lagoon and covered with clean material creating confined aquatic disposal sites. In 1999, however, Ross Island Sand and Gravel and DEQ determined that mining activities had extended into one of the capped areas, resulting in a breach of a confined cell.

Between 1999 and 2002, Ross Island Sand and Gravel and the Port of Portland conducted environmental investigations at the site, finding that the following contamination could pose unacceptable risk to human health and the environment:
Elevated concentrations of zinc and arsenic in surface soil samples collected in the vicinity of the processing plant.
PAHs, detected in surface soil immediately adjacent to the southern portion of the lagoon at concentrations that could pose a threat to fish and wildlife within the lagoon if soil erodes into the lagoon.
Contaminated material removed from lagoon disposal cell 5 during mining activities.
PAHs detected at levels slightly exceeding EPA ambient water quality criteria in a grab groundwater sample collected adjacent to the southern portion of the lagoon.
Elevated concentrations of PAHs, metals, and PCBs detected in a limited number of surface sediment samples collected from the southern portion of the lagoon where reclamation filling occurred and in the vicinity of the recapped breach area.
Elevated pH detected at several locations along the southern shoreline of the lagoon assumed to result be from concrete waste fill.
Highly contaminated material present in the five confined disposal cells for material dredged from Port of Portland facilities.
Manner and Time of Release: Disposal of contaminated dredge sediments in upland and lagoon areas.
Hazardous Substances/Waste Types: PCBs, PAHs, petroleum, metals, pesticides/herbicides
Environmental/Health Threats:
Status of Investigative or Remedial Action: (August 2011 update) Ross Island Sand and Gravel has completed the following actions in compliance with the December 2005 DEQ Record of Decision:
In summer 2000, closed the eastern portion of the settling pond containing contaminated material mined from confined aquatic disposal cell 5 and covered it with clean sediments dredged from the western portion of the settling pond.

In June and July 2007, removed approximately 900 cubic yards of soil contaminated with metals from the processing plant area; placed the soil in a prepared cell located within the capped former settling pond; and capped the cell with clean soil.

In summer and fall 2007, installed a variety of erosion control measures in the southern shoreline areas immediately adjacent to the lagoon. Measures included: installing drainage berms, stabilizing slopes, and covering with clean fill.

In May 2007, sampled groundwater in the southern shoreline area. Contaminant concentrations did not exceed conservative screening levels and DEQ determined no further action for groundwater was necessary.

Between 2001 and 2010, placed approximately 2,400,000 tons of fill in the lagoon achieving a minimum three-foot cap of clean material over contaminated sediment and further stabilizing slopes adjacent to the southern bench area.

Ross Island Sand and Gravel prepared a long-term monitoring/maintenance and contingency plan for the site addressing each aspect of the cleanup. In addition to regular monitoring and maintenance of cleanup components, Ross Island will inspect caps and stormwater controls after any extreme events including: seismic events of magnitude six or greater, rainfall exceeding 3.4 inches or greater in a 24-hour period, and Willamette River levels of 18 feet or greater.

Based on evaluation of the actions described above, DEQ has determined that no further action, aside from monitoring, is required at the Ross Island Sand and Gravel site and that Ross Island Sand and Gravel has completed its obligations under DEQ Consent Order No. WMCVC-NWR-99-09. The completed cleanup is conditional because of the need to maintain engineering controls and conduct long-term monitoring and maintenance of cleanup measure at the site. The new consent order addresses DEQ oversight of these on-going responsibilities.

A memorandum describing the basis for the no further action and certificate of completion was made available for public review and comment from April 4 to May 2, 2011. No comments were received.

The first annual long-term monitoring report was submitted in July 2012. It identified continued issues with elevated pH in one area and need for improving slopes adjacent to sediment caps in another area. RISG is addressing these issues with additional fill placement focused in these areas. Annual monitoring reports submitted 2013, 2014, 2015, and 2016. pH levels declined and pH monitoring was discontinued in 2015. Site gw monitoring wells were decommissioned 2014/2015.
Data Sources: Final Site Investigation Report - Port of Portland Confined Dredged Material Disposal, Ross Island Facility (November 30, 2000); Remedial Investigation/Risk Assessment Report Ross Island Sand and Gravel Co. (October 21, 2002).

Substance Contamination Information

Substance Media Contaminated Concentration Level Date Recorded
COPPER Sediment 2,790 ppm 1/1/1992
PCBs Sediment 17 ppm 1/1/1992
TRIBUTYLTIN Sediment 8.85 ppm 1/1/1992

Investigative, Remedial and Administrative Actions

Action Start Date Compl. Date Resp. Staff Lead Pgm
No Further Action (Conditional)  (Primary Action) 06/29/2011 06/29/2011 Jennifer Sutter SRS
View Full Report Showing Action History

Site Environmental Controls

Control Description Begin Date End Date Last Reviewed By Last Review Date
Easement Equitable Servitude 06/30/2011   Jennifer Sutter 06/30/2011
  Comments: An E&ES documenting locations of containment areas and stabilization elements and referencing the long-term maintenance and monitoring plan has been filed with Multnomah County.
Contamination left in place, sediment or sludge 08/01/2011   Jennifer Sutter
  Comments: RISG prepared a Long-Term Monitoring/Maintenance and Contingency Plan (February 2011) for the site addressing each aspect of the remedial action. Basic elements of the plan for each remedial action element are identified below. In addition to the regular monitoring described, inspections of caps and stormwater controls will be conducted after any extreme events including: seismic events of magnitude 6 or greater, rainfall exceeding 3.4 inches or greater in a 24-hour period, and Willamette River levels equivalent to a 100-year flood or higher.

Key to Certain Acronyms and Terms in this Report:

For more information on this site contact the Northwest regional office.