RAMCO occupied a building located within the Dallesport Industrial Park, where it extracted aluminum from dross it received from primary aluminum smelters. Dross is a by-product from the primary smelting process, and the major constituents of dross are aluminum, aluminum oxides, mixtures of nitrides, mixtures of chlorides, and traces of other impurities.
The extraction process consisted of heating the dross in a gas-fired furnace, and adding sodium chloride to the furnace as a fluxing agent. At the end of a run, molten aluminum was tapped out of the furnace into ingots. The molten salt remaining in the furnace then was skimmed out of the furnace either into metal molds or onto a bed of sand on a concrete floor, where it cooled and hardened. The salt cake was then a waste that required management and disposal. Salt cake is composed primarily of sodium chloride, aluminum oxide, and aluminum metal.
From approximately 1982 to 1989, RAMCO placed this salt cake plus a smaller amount of baghouse dust in an unlined disposal site at a location separated from the RAMCO buildings by about ½ mile. RAMCO ceased placing material in the unlined landfill in approximately 1989. RAMCO ceased operations in the Dallesport Industrial Park in approximately 1993.
Potential human health and environmental impacts from former industrial operations and disposal include public health and ecosystem risks, and potential increased total dissolved solids and metal concentrations in ground water and surface water.
The disposal site is located in the Dallesport Industrial Park, which is owned and operated by the Port of Klickitat. The industrial park is a mixed light and heavy industrial facility, and is approximately two miles east of the small community of Dallesport, Washington. The 2007 population of Dallesport is 1,239.
The unlined and uncovered disposal site is located about 400 feet southwest of Spearfish Lake, about 500 feet north Joe’s Lake, and about 1000 feet north of the Columbia River.
The Washington State Department of Natural Resources, Natural Heritage Program indicated the Western Pond Turtle may inhabit the adjoining lakes. The Western Pond Turtle is considered a species of concern in Washington State.
The aluminum waste disposal site covers approximately 1.5 acres and is located within the 650-acre industrial park. At one time, the site contained an estimated 63,200 cubic yards of waste with the waste being approximately 30 feet deep at its deepest point.
Access to the waste disposal site is partially restricted. The site is presently surrounded by a barb wire fence along the eastern border, temporary rental fencing and a gate surround the remainder of the site. The fencing is currently provided through a company contracted by the Washington Department of Ecology. The site is in a rural area and the fencing is not inspected or maintained.
The contaminants of concern (cyanide, polycyclic aromatic hydrocarbons [PAHs], ammonia, and metals including aluminum, cobalt, copper, iron, manganese, and vanadium) are potential hazardous substances or pollutants or contaminants as defined by sections 101(14) and 101(33) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended, 42 U.S.C. section 9601(14) and (33).
In 1993, Hart Crowser, on behalf of the former owner of RAMCO, sampled and tested salt cake wastes generated during the recovery of aluminum from aluminum dross from three aluminum smelters at RAMCO. Based on the results of the tests, newly generated salt cake would be a designated dangerous waste because it is aquatically toxic. The test results also demonstrated that salt cake waste which is crushed and allowed to aerate can experience a significant reduction in aquatic toxicity.
In June and July of 2005, the Washington State Department of Ecology (Ecology) oversaw installation of five groundwater monitoring wells adjacent to the unlined disposal site to determine the depth to groundwater and the impacts the site may be having on the groundwater in the area. Results of the investigation are summarized below.
The waste in the landfill contains up to 28 percent aluminum, up to 8 percent sodium, up to 2.8 percent magnesium, up to 2.1 percent calcium, up to 1.5 percent potassium, plus lesser amounts of chromium, manganese, iron, copper, nickel, and zinc.
The waste material placed in the landfill produced ammonia gas when wet. The odor of ammonia has been detected in the past during direct push soil sampling, groundwater monitoring, and after rainfall events.
Nitrates, sodium, chloride, and total dissolved solids in groundwater have been measured at levels exceeding primary or secondary water quality standards. Because major salt-forming chemical elements (sodium, calcium, potassium) measured during groundwater sampling exceeded levels of these elements found in seawater, there is a strong indication that salts from the landfill are leaching into groundwater.
Leaching tests performed to determine whether the waste is a Dangerous Waste indicate that metals also could leach from the aluminum waste. However, groundwater monitoring thus far has not shown elevated levels of metals attributable to leaching from the landfill.
In April 2006, Ecology oversaw additional sampling of the aluminum waste in the disposal site using a direct push soil probing machine. A key finding from one boring was a zone at the bottom of the aluminum waste (27 to 29 feet below the surface of the landfill cover) with perched water, an elevated temperature, and a strong odor of ammonia gas. In addition, the direct push soil probe was not able to penetrate a dense layer approximately eight feet below the surface in the center of the landfill. Ecology conducted a Site Hazard Assessment pursuant to the Ecology Model Toxics Control Act (MTCA) on the unlined waste disposal site. The site was added to the State Hazardous Sites List, and is among the upper 40 percent of sites according to the risk it presents.
In Spring 2009, the U.S. Environmental Protection Agency (EPA), along with Ecology and the U.S. Army Corps of Engineers, conducted a visit of the RAMCO waste disposal site. Participants observed waste aluminum and possibly spent pot lining, a waste product of the electrolytic process of smelting aluminum. The spent pot lining is classified as RCRA K088 hazardous waste (spent aluminum pot liner from primary aluminum reduction) because of quantities of cyanide and/or fluoride .
In Summer 2009, EPA conducted a focused removal assessment of the aluminum waste disposal site. Environmental samples were collected from aluminum waste stockpiles, buried aluminum waste, groundwater, and nearby surface water. The results of the investigation are summarized below . Full results are in the attached table.
The following analytes exceeded EPA’s Regional Screening Levels for Chemical Contaminants at Superfund Sites in industrial soils: the polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, dibenz[a,h]anthracene, and indeno[1,2,3-cd]pyrene; and the metals aluminum, cobalt, copper, iron, manganese, and vanadium.
Groundwater samples were collected from three monitoring wells. Chloride, fluoride, nitrate, nitrite and cyanide as hydrogen cyanide were detected above EPA drinking water standards or Regional Screening Levels,
