Sediment Contamination Guide:
Time Line
1896
Trail, Canada facility built as a copper smelter.
1906 Trail, Canada facility converted to lead and zinc smelter.
1900-1922
Mining, milling and smelter activities active in both Canada and the United States, all of which discharge metals into the Upper Columbia and its tributaries. 
Smelters permanently close at Northport, Grand Forks, Greenwood and Boundary Falls.
1931
A new Canadian fertilizer plant built to reduce sulphur dioxide emissions becomes a primary source of phosphate discharges into the Columbia.
1942
Grand Coulee Dam gates close, raising the waters behind the dam 380 feet. Water flows and bank erosion changes, affecting depositional patterns of sediment contamination.
1960
Celgar Pulp Mill begins operation.
1978-1991
Trail smelter improvements result in declining discharge of slag and effluent to air and river.
1990-1993
WA Department of Ecology (Ecology) monitors dioxin, furan and trace metal concentrations in suspended particulate matter and fish tissues. The Celgar pulp mill is considered the primary historical source for dioxin and furan contaminants. Celgar plant modernization designed to end discharges of dioxins and furans into the Columbia.
1992
The USGS conducts a sediment study of Lake Roosevelt describing the transport of metals, the presence of trace metals in bed sediment, and the toxicity of the sediment to benthic invertebrates.
1993
Ecology initiates studies to determine if Lake Roosevelt should be placed on the federal Clean Water Act Section 303(d) list of impaired water bodies.
1994
Canadian fertilizer plant ceases discharge of phosphate into the Columbia.
1994
The USGS conducts a fish tissue study to determine the level of mercury and other metals in walleye, smallmouth bass and rainbow trout. Based on findings, a fact sheet from the Washington State Department of Health (WDOH) advises the public to limit consumption of walleye.
1995
Discharges of slag from Trail smelter cease.
1997
New Trail smelter further reduces metals in effluent discharges.
1998
In Canada, wide area human and ecological risk assessment initiated from Castlegar to the U.S. border.
1998
USGS conducts a follow-up fish tissue study and finds that concentration levels of metals had either not changed or decreased. Ecology identifies temperature, total dissolved gas, mercury, PCBs and pH as parameters for Lake Roosevelt inclusion on the Clean Water Act 303(d) list of impaired water bodies.
1999
Colville Confederated Tribes petition EPA to conduct an assessment of environmental contamination in Lake Roosevelt under federal Superfund program.
2001
USGS begins multi-year study to determine possible effects of contaminants in wind blown dust.
2001-2003
EPA collects samples of river sediments and issues draft and final site inspection reports. EPA recommends a Remedial Investigation Feasibility Study (RI/FS) to assess environmental and human health risks.
2002
USGS collects core samples to evaluate processes related to the movement of metals in the system.
2003
USGS collects core samples to assess effects of metals in bed sediment on water and biota.
2003
After negotiations between EPA and Teck Cominco reach an impasse, EPA issues Unilateral Administrative Order under U.S. Superfund law to fund and conduct aspects of the RI/FS. Teck Cominco contests the order and EPA moves forward with the RI/FS using U.S. government funding.
2004
Canadian government issues a “Diplomatic Note” to the U.S. State Department regarding EPA enforcement order. United States and Canadian governments begin discussions regarding site.
2004
EPA issues RI/FS scoping plan, including a review of all known data and studies related to sediment contamination issues.
2004
Colville Confederated Tribes and Washington State ask U.S. District Court to force Teck Cominco to comply with EPA order issued in 2003. Teck Cominco continues to maintain they are not subject to U.S. environmental laws.
2004
Ecology updates Clean Water Act 303(d) impair-ment list for Lake Roosevelt to include temperature, total dissolved gas and mercury.
2005
EPA RI/FS studies begin by initiating sediment sampling and fish tissue studies.