Superfund and Mining Megasites Lessons from the Coeur d'Alene River Basin (2005) / Chapter Skim
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4 Remedial Investigation Assessment
4 Remedial Investigation Assessment
Pages 108-160
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From page 108... ...
. This site, commonly referred to as the Bunker Hill "box," encompasses a 21-square-mile area including the historic smelter and ore-processing operations in the heart of the Coeur d'Alene River basin.
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From page 109... ...
, undertaken concurrent with the RI, characterizes heavy-metal contamination in relation to potential human health risks. EPA'S RECOGNITION OF THE BASIN SYSTEMS AND THEIR INTERACTIONS The Coeur d'Alene River basin is a large-scale, complex system with extensive anthropogenic overprints that have increased the multiple complexities and interacting processes at work throughout the basin.
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From page 110... ...
Based on a systems approach, the RI should look at the watershed boundaries defining the basin system and then develop a flux-reservoir model of where each metal of importance 2The watershed is also referred to as a catchment or drainage basin. 3These units include: CSM Unit 1, upper watersheds; CSM Unit 2, midgradient watersheds; CSM Unit 3, Lower Coeur d'Alene River; CSM Unit 4, Coeur d'Alene Lake; CSM Unit 5, Spokane River.
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From page 111... ...
REMEDIAL INVESTIGATION ASSESSMENT 111 BOX 4-1 Systems Approach "In the context of water resources the essential function of a systems ap proach is to provide an organized framework that supports a balanced evalua tion of all relevant issues (e.g., hydrologic, geomorphic, ecologic, social, eco nomic) at appropriate scales of space and time.
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From page 112... ...
1988) that looked at the water quality monitoring in the Coeur d'Alene River basin: A whole basin environmental management approach to the Coeur d'Alene system should also address the relative importance of habitat degradation and other factors (for example, nonpoint impacts from agricultural or forestry practices)
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From page 113... ...
For example, privately-owned properties on different sides of the dividing line could have similar levels of contamination, but properties outside the box had to wait a decade before becoming part of the Superfund site and be considered for remediation.5 Operable Unit 3 EPA has substantial flexibility under the NCP in establishing what areas or actions will constitute an OU at a site.6 However, the guidance does state that "sites should generally be remediated in operable units when ... phased analysis and response is necessary or appropriate given the size or complexity of the site, or to expedite the completion of total site cleanup." Certainly, the Coeur d'Alene River basin is such a site though the entire basin (minus the box)
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From page 114... ...
SAMPLING AND ANALYSIS Samples Collected Some 7,000 samples had been collected in the Coeur d'Alene River basin between 1991 and 1999 by the Idaho Department of Environmental Quality, the U.S. Geological Survey (USGS)
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From page 115... ...
These samples were collected from sediments, sediment cores, adits, seeps, creek surface waters, soils, drinking water (wells, residential, and school/daycare) , indoor dust, vacuum cleaner bags, lead-based paint, and groundwater.
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From page 116... ...
116 SUPERFUND AND MINING MEGASITES acres and are listed in Appendix I of the RI. Major tailings, waste rock, and floodplain sources of metal contaminants were identified by EPA as to location and area.
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From page 117... ...
receiving the most attention from EPA for the Coeur d'Alene River basin system are lead and 10EPA uses the term "chemical of potential concern" (COPC) when considering all the substances (metals in the case of the Coeur d'Alene River basin)
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From page 118... ...
EPA uses dissolved zinc concentrations as an indicator of the behavior of each dissolved chemical of concern and total lead concentrations as an indicator of the behavior of each total chemical of concern to avoid having to consider each chemical of concern separately (URS Greiner, Inc.
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From page 119... ...
Little information is available on metal transport in groundwater around Lake Coeur d'Alene and along the upper Spokane River (URS Greiner, Inc.
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From page 120... ...
. This approach could be used as part of a site-characterization strategy in the Coeur d'Alene River basin.
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From page 121... ...
and CH2M Hill 2001a) and are used to characterize dissolved metals, total lead, and sediment for the entire basin excluding Lake Coeur d'Alene.12 The committee found that the analyses provided for zinc and lead are useful for understanding the contributions of various tributaries and largescale geographic areas to metal loadings in the basin by providing a central estimate at each gauging location.
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From page 122... ...
DETERMINING BACKGROUND CONCENTRATIONS For the purpose of identifying areas within the Coeur d'Alene and Spokane River basins that are contaminated by mining wastes, EPA (URS Greiner, Inc.
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From page 123... ...
, and the Spokane River Basin from the city of Coeur d'Alene to Lake Roosevelt on the Columbia River. EPA included Lake Coeur d'Alene in the lower basin, justifying this because the lake is part of the Coeur d'Alene River complex that supplies metal contaminants to downstream ecosystems.
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From page 124... ...
Data from the other location (CC464) had samples at 5, 20, and 43 feet, and the lead concentrations dropped with increasing depth from 6,790 milligrams per kilogram (mg/kg)
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From page 125... ...
(2001) noted that sample intervals crossing the contact between the lead-rich sediment and the underlying lead-poor sediment will dilute and underestimate the lead content of the lead-rich segment.
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From page 126... ...
Regardless, all these concentrations are quite similar, especially in contrast to the high concentrations of metals detected in contaminated sediments, which are orders of magnitude higher. EPA derived the background concentrations for the COPCs in the sediments of the Spokane River basin with data for 27 soil samples, collected to depths of up to 3 feet (San Juan 1994)
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From page 127... ...
For water, soils, and sediments in the tributaries of the South Fork of the Coeur d'Alene River (upper basin) and sediments in the Spokane River basin, the committee concludes that the background determinations are reasonable but limited by the issues presented in this section.
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From page 128... ...
and CH2M Hill 2001a) , on chemical speciation and transport of metals in the Coeur d'Alene River system, Lake Coeur d'Alene, and the Spokane River.
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From page 129... ...
. understanding speciation was not necessary to evaluate health risks" (EPA 2004 [May 17, 2004]
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From page 130... ...
Since the RI was issued in 2001, the USGS has provided a more comprehensive understanding of sediment transport in the Coeur d'Alene system (Clark 2003; Bookstrom et al.
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The ability of the model to predict postremediation changes is addressed in Chapter 8 of this report. Chemical Speciation and Sediment Transport in the Upper Basin (CSM Unit 1)
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From page 132... ...
132 SUPERFUND AND MINING MEGASITES ascertain chemical speciation. In Canyon Creek and Ninemile Creek, pH measurements of surface water varied from slightly acidic for some adits and seeps to slightly alkaline for in-stream measurements.
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From page 133... ...
The sediment transport data for Ninemile Creek are unclear. Different values of annual sediment transport loads are reported in the RI for water TABLE 4-2 Water Year 1999 Sediment Transport Loads for Upper Basin Watersheds Sediment Transported in Water Year 1999 Watershed Tons Tons/Square Mile Canyon Creek 1,440 62 Beaver Creek No data available No data available Big Creek 1,400 (estimated from No data available Canyon and Ninemile Creeks)
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From page 134... ...
Examination of some historical records indicated that sediment transport in some tributaries was less in water year 1999 than in some previous years. EPA attributed this to remedial actions that have been undertaken in some watersheds (URS Greiner, Inc.
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From page 135... ...
. However, chemical speciation information for groundwater (or other media)
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From page 136... ...
(2002) summarized findings on metal speciation and mobility of metals in the Coeur d'Alene River basin that were more extensive than the information available at the time the RI 18This study was conducted in support of the RI (URS Greiner, Inc.
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From page 137... ...
Researchers at the University of Wisconsin-Eau Claire have also completed considerable work on chemical speciation (Morrison et al.
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From page 138... ...
. Since the release of the RI in 2001, much new information on sources, deposition, and transport of sediments and lead concentrations of the sediments on the bed, banks, natural levees, and flood basins of the main stem of the Coeur d'Alene River has been developed and documented by the USGS.
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From page 139... ...
and output (Spokane River) for Coeur d'Alene Lake, water year 1999.
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From page 140... ...
The riverine inputs and Lake Coeur d'Alene output are derived from USGS water monitoring from water year 1999 (Woods 2001) , the benthic input is estimated from USGS studies (Kuwabara et al.
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From page 141... ...
REMEDIAL INVESTIGATION ASSESSMENT 141 140 8 ) L/gµ( 120 7.5 D Zn issolved solvedsi 100 7 O 2 Main channel (m Kuwabara et al.
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From page 142... ...
And, again, the "transformation parameter" (in this model, a "scavenging coefficient") is solely a fitting factor designed to comport the model's output with the measured zinc concentrations in Lake Coeur d'Alene discharge.
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From page 143... ...
and CH2M Hill 2001l) from this event indicated elevated lead concentrations transported through the lake.
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5-9) , Lake Coeur d'Alene is dimictic (thermal stratification breaks down and the water column undergoes mixing, or turnover, in the fall and spring)
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From page 145... ...
A nutrient load/lake response model was used to simulate Lake Coeur d'Alene's limnologic21 responses to alterations in water and nutrient loads delivered to the lake. The empirical mathematical model simulated the following eutrophicationrelated variables22: concentrations of total phosphorus, total nitrogen, and chlorophyll a; secchi-disc transparency;23 and hypolimnetic dissolved oxygen deficit.
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From page 146... ...
Two commonly used procedures to infer the chemical speciation of metals in aquatic sediments are the Tessier sequential fractionation procedure (Tessier et al.
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From page 147... ...
However, the fact that the samples were from cores that were sectioned at 8 cm intervals and AVS-SEM assayed at 4 cm intervals casts doubt on the association of the metals at the water-sediment interface. Lake Coeur d'Alene Studies: The Bottom Line What can be easily understood from evaluating the complex phenomena in Lake Coeur d'Alene is that the better the data sets, the more thorough the understanding and ability to make informed statements about metals dynamics in the lake.
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From page 148... ...
Chemical Speciation It appears that few chemical speciation studies have been conducted in the Spokane River basin. As provided by Kadlec (2000)
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From page 149... ...
of the Coeur d'Alene River basin system. Because the basin has not been considered in the framework of a system and inadequate attention has been devoted to hydrologic and climatic variabilities, in particular, the CSMs seemingly are based primarily on average conditions.
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From page 150... ...
A systems approach based on watershed boundaries is a more appropriate means of properly characterizing contaminant sources and paths of contaminant transport. Although the committee recognizes that the OU approach was adopted by EPA to prioritize human health risks, the artificial constraints have created problems for EPA in protecting fish downstream of the box, because a large portion of the dissolved zinc (modeled at 41%)
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From page 151... ...
Zinc accounts for about 96% of the dissolved metal loading to Lake Coeur d'Alene. Lead is primarily transported as a particulate and is also a metal of major concern.
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From page 152... ...
However, this has little practical effect because proposed remedial actions are not governed by background concentrations. Conclusion 8 Owing to the complexity of metals dynamics in Lake Coeur d'Alene, additional supporting technical information is needed to develop an effective lake management plan.
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From page 153... ...
Presentation at the Third Meet ing on Superfund Site Assessment and Remediation in the Coeur d'Alene River Basin, June 17, 2004, Coeur d'Alene, ID. Balistrieri, L.S., A.A.
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From page 154... ...
2002. Impacts of historical mining in the Coeur d'Alene River Basin.
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From page 155... ...
2003. Occurrence and Transport of Cadmium, Lead, and Zinc in the Spokane River Basin, Idaho and Washington, Water Years 1999-2001.
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From page 156... ...
2000. Benthic Flux of Metals and Nutrients into the Water Column of Lake Coeur d'Alene, Idaho: Report of an August, 1999, Pilot Study.
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From page 157... ...
2004. River Basins and Coastal Systems Planning Within the U.S.
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From page 158... ...
3) Estima tion of Background Concentrations in Soil, Sediment, and Surface Water in the Coeur d'Alene and Spokane River Basins.
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From page 159... ...
2001. Concentrations and Loads of Cadmium, Lead, Zinc, and Nutrients Mea sured During the 1999 Water Year Within the Spokane River Basin, Idaho and Wash ington.
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From page 160... ...
Presenta tion at the Third Meeting on Superfund Site Assessment and Remediation in the Coeur d'Alene River Basin, June 17, 2004, Coeur d'Alene, ID. Woods, P.F., and M.A.
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