NPL-U30-2-9-R9 LEVIATHAN MINE Contact Person: Carolyn Douglas, EPA Region IX

Transcription

NPL-U30-2-9-R9
HRS DOCUMENTATION RECORD—REVIEW COVER SHEET
Name of Site: LEVIATHAN MINE
Contact Person:
Carolyn Douglas, EPA Region IX
(415) 744-2343
Karen Johnson, Ecology and Environment, Inc.
(415) 981-2811
Site Investigation:
Documentation Record:
Pathways, Components, or Threats Not Scored:
The ground water pathway was evaluated, but not scored because no wells are known to be used for drinking
water or irrigation supply within 4 miles of the mine. The air and soil exposure pathways were not scored
because no residences, schools, or regularly occupied structures are known to exist within 4 miles of the mine.
HRS DOCUMENTATION RECORD
Name of Site: Leviathan Mine
EPA ID#: CAD980673685
EPA Region: 9
Date Prepared: July 8, 1999
Street Address of Site: Not Available
County and State: Alpine County, California
Topographic Map: Topaz Lake, 7.5-Minute
Latitude: 38o 42N 14.0O N.
Longitude: 119o 39N 22.0O W.
Scores
Ground Water Pathway
Surface Water Pathway
Soil Exposure Pathway
Air Pathway
0.00
100.00
0.00
0.00
HRS SITE SCORE
50.00
1
HAZARD RANKING SYSTEM
SUMMARY SCORESHEETS
SITE NAME: Leviathan Mine
CITY/COUNTY/STATE: Markleeville, Alpine County, CA
EPA ID #: CAD980673685
EVALUATOR: K. Johnson
DATE: 7/8/99
LATITUDE: 38E42'14.0"N
LONGITUDE: 119E39'22.0"W
S
S2
Groundwater Migration Pathway Score (Sgw)
NQ
GG
Surface Water Migration Pathway Score (Ssw)
100
10,000
Soil Exposure Pathway Score (Ss)
NQ
GG
Air Migration Pathway Score (Sa)
NQ
GG
Sgw2 +Ssw2 + Ss2 + Sa2
XXXXXXXX
10,000
(Sgw2 +Ssw2 + Ss2 + Sa2) / 4
XXXXXXXX
2,500
/(Sgw2 +Ssw2 + Ss2 + Sa2) / 4
XXXXXXXX
2
50.0
SURFACE WATER OVERLAND/FLOOD MIGRATION COMPONENT SCORESHEET
Factor Categories and Factors
DRINKING WATER THREAT
1.
2.
3.
4.
5.
Maximum
Value
550
Likelihood of Release
Observed Release
Potential to Release by
Overland Flow
2a.
Containment
2b.
Runoff
2c.
Distance to Surface Water
2d.
Potential to Release by
Overlands Flow [lines
2a x (2b+2c)]
Potential to Release by Flood
3a.
Containment (Flood)
3b.
Flood Frequency
3c.
Potential to Release
by Flood (lines 3a x 3b)
Potential to Release
(Lines 2d+3c, subject to a
maximum l of 500)
(Higher of lines 1 or 4)
Assigned
Value
550
10
25
25
________
________
________
500
________
10
50
________
________
500
________
500
________
550
550
a
a
10,000
106
100
100
50
0
b
b
b
b
5
b
________
________
________
________
5
5
100
3.33
Waste Characteristics
6.
7.
8.
Toxicity/Persistence
Hazardous Waste Quantity
(lines 6 x 7, then assign a
value from Table 2-7)
Targets
9. Nearest Intake
10. Population
10a. Level I Concentrations
10b. Level II Concentrations
10c. Potential Contamination
10d. Population (lines 10a + 10b +10c)
11. Resources
12. Targets (lines 9+10d+11)
13. Drinking Water Threat
[(Lines 5 x 8 x 12)/82,500, subject
to a maximum of 100]
3
Maximum
Value
Assigned
Value
HUMAN FOOD CHAIN THREAT
14. Likelihood of Release (Same value
as line 5)
550
550
a
a
5x107
106
1,000
560
50
45
b
b
b
b
b
0
0.3
—
45.3
45.3
100
100
15. Toxicity/Persistence/Bioaccumulation
16. Hazardous Waste Quantity
17. Waste Characteristics
(Toxicity/Persistence x Hazardous Waste
Quantity x Bioaccumulation, then
assign a value from Table 2-7)
Targets
18. Food Chain Individual
19. Population
19c. Potential Human Food Chain Contamination
19d. Population (lines 19a + 19b + 19c)
20. Targets (lines 18 + 19d)
Human Food Chain Threat Score
21. Human Food Chain Threat
[(Lines 14 x 17 x 20)/82,500 subject
to a maximum of 100]
4
Maximum
Value
Assigned
Value
ENVIRONMENTAL THREAT
22. Likelihood of Release
(Same value of line 5)
550
550
a
a
5x106
106
1,000
1,000
b
b
b
750
0
0
b
b
750
750
60
60
23. Ecosystem Toxicity/Persistence/Bioaccumulation
24. Hazardous Waste Quantity
25. Waste Characteristics
(Ecosystem Tox./Persistence x Hazardous Waste
quantity x Bioaccumulation, then assign a
value from Table 2-7)
Targets
26. Sensitive Environments
26c. Potential Contamination
26d. Sensitive Environments
(lines 26a + 26b + 26c)
27. Targets (Value from line 26d)
Environmental Threat Score
28. Environmental Threat Score
[(lines 22 x 25 x 27)/82,500
subject to a maximum of 60]
SURFACE WATER OVERLAND/FLOOD MIGRATION COMPONENT SCORE FOR A WATERSHED
29. Watershed ScoreC
[(Lines 13 + 21+ 28),
subject to a maximum of 100]
100
100c
SURFACE WATER OVERLAND/FLOOD MIGRATION COMPONENT SCORE
30. Component Score (Sof)C
(Highest score from Line 29
for all watersheds evaluated,
subject to a maximum of 100)
100
_______________________
a Maximum value applies to waste characteristics category.
b Maximum value not applicable.
c Do not round to the nearest integer.
5
100c
REFERENCES
Reference
Number
Description of References
1
Code of Federal Regulations (CFR), Title 40 Part 300, Appendix A, Hazard Ranking System. [not
included in documentation record]
2
U.S. Environmental Protection Agency (EPA), Superfund Chemical Data Matrix, EPA/540/R96/028, Publication 9345.1-21, June 1996. 11 pp.
3
U.S. Geological Survey (USGS), Map of Smith Valley, NV-CA, 1:100,000-scale metric topographic
map, 1985.
4
California Regional Water Quality Control Board, Lahontan Region (RWQCB), "Leviathan Mine 5Year Workplan, July 1995. 40 pp.
5
Brown and Caldwell Consulting Engineers, "Leviathan Mine Pollution Abatement Project Design
Report and Draft Environmental Impact Report," prepared for RWQCB, April 1983. 45 pp.
6
Kukol, Tom, RWQCB, "Leviathan: State of the Mine, Spring of 1987," May 1987. 14 pp.
7
Taxer, Eric, et al., RWQCB, "A History of the Leviathan Mine Pollution Abatement Project, Alpine
County, California," April 1991. 20 pp.
8
RWQCB, "Draft Operation and Maintenance Plan, Leviathan Mine Pollution Abatement Project,"
November 21, 1986. 6 pp.
9
Greystone Development Consultants, Inc., "Preliminary Assessment, Leviathan Mine Site Final
Report," submitted to: Toiyabe National Forest, U.S. Department of Agriculture Forest Service,
May 1991. 13 pp.
10
Hammermeister, Dale P, and Stephen J. Walmsley, "Hydrologic Data for Leviathan Mine and
Vicinity, Alpine County, California, 1981-83, U.S. Geological Survey Open File Report 85-160,
1985. 30 pp.
11
U.S. Department of Energy, Pittsburgh Research Center, "Feasibility of Lime Treatment at the
Leviathan Mine Using the In-Line System," prepared for RWQCB, undated (work began April
1996). 7 pp.
12
California Division of Mines and Geology, Mines and Mineral Resources of Alpine County,
California, County Report 8, 1977. 7 pp.
13
Franks, A.L., RWQCB, "Geologic Report on Source of Mineral Water from Leviathan Mine, Alpine
County, California," October 17, 1969. 9 pp.
14
Nordyke, Lewis, "Mining with Anaconda," The Explosives Engineer, November-December 1955,
pp. 167-182. 3 pp.
15
RWQCB, "Report on Pollution of Leviathan Creek, Bryant Creek and the East Fork Carson River
Caused by the Leviathan Sulphur Mine," January 1975. 32 pp.
6
16
Webster, Jenny G., et al., "Transport and Natural Attenuation of Cu, Zn, As, and Fe in the Acid
Mine Drainage of Leviathan and Bryant Creeks," in The Environmental Geochemistry of Sulfide
Oxidation," C.N. Alpers and D.W. Blowes, Eds., ACS Symposium Series, Washington, D.C.,
American Chemical Society, 1993. 2 pp.
17
Leggett, J.T., Executive Officer, RWQCB, memo to Board Members, re: Leviathan Sulphur Mine
Drainage, September 21, 1965. 2 pp.
18
RWQCB, Leviathan Mine water quality data summary sheets, provided by Brian Johnson, RWQCB,
August 15, 1997. 20 pp.
19
Brown, Artie G., California Department of Fish and Game, memo to Fred R. McLaren, RWQCB,
re: Historic Facts of Leviathan Creek, November 24, 1968. 1 p.
20
California Department of Fish and Game, memo to J.T. Leggett, RWQCB, re: Leviathan Mine
Pollution, Alpine County, July 30, 1969. 6 pp.
21
Martin, John H., Beavers and Young, letter to Ron Brown, EPA Waste Compliance Branch, re:
Leviathan Mine, Alpine County, CA, May 27, 1997. 7 pp.
22
Holley, Colleen, and Leroy McLelland, Nevada Division of Wildlife, telephone conversation with
Karen Johnson, Ecology and Environment, Inc., May 6, 1998. 1 p.
23
Herbst, David, B., Sierra Nevada Aquatic Research Laboratory, University of California, "Aquatic
Invertebrate Bioassessment Monitoring of Acid Mine Drainage Impacts in the Leviathan Creek
Watershed (Alpine County, California)," submitted to RWQCB, June 26, 1997. 7 pp.
24
U.S. Fish and Wildlife Service, "Recovery Plan for the Lahontan Cutthroat Trout," January 1995.
8 pp.
25
California Department of Health Services, Water Quality Monitoring Database, as provided in Site
Report for Leviathan Mine, produced by USEPA Region 9, GIS Center, September 9, 1997. 4 pp.
26
Stetler, Chris, RWQCB, memo to Members of the Leviathan Mine Council, re: Water Quality and
Flow Data for Leviathan Mine, Water Year 1998, November 19, 1998. 12 pp.
27
Beck, James, J.M. Beck & Associates, letter to Kevin Mayer, EPA, re: Evaporation Pond Data,
February 16, 1999. 14 pp.
28
Lehr, Stafford, California Department of Fish and Game, Letter to Kevin Mayer, EPA, re: Genetic
Analysis of Fish Captured in Upper Leviathan Creek, March 17, 1999. 5 pp.
Figures
1
Leviathan Mine Site Layout (ref. 4, pp. 25 and 34; ref. 7, p. 12; ref. 10, pp. 3 and 6).
2
Leviathan Mine Site Location Map (ref. 3; ref. 10, p. 6).
7
SD-Characterization and Containment
Source 1
SOURCE DESCRIPTION
2.2
Source Characterization
Source Description: Source 1 — Acid Mine Drainage
Source Type — Other
Source 1 consists of acid mine drainage (AMD) generated at Leviathan Mine between the time Anaconda ceased
mining operations at the site in late 1962 and construction of the Pollution Abatement Project1 began in August
1983 (ref. 4, pp. 6 and 27). The AMD generated at the mine subsequent to the construction is addressed in
Source 2, Evaporation Ponds.
AMD results from the oxidation or decomposition of sulfides and sulfosalts commonly found with mineralized
ores, such as those known to exist at Leviathan Mine (ref. 5, p. 3-17). An ore such as iron sulfide (pyrite) reacts
with water and oxygen to form sulfuric acid and ferrous sulfate (ref. 5, p. 3-17). Other ores oxidize under AMD
conditions to release metallic, non-metallic, and sulfate ions to the environment (ref. 5, p. 3-17). Copper, cobalt,
manganese, zinc, and nickel all form soluble salts under AMD conditions (ref. 5, p. 3-18). AMD at Leviathan
Mine is generated by regional ground water, percolating rainfall and snowmelt, or surface water flows (Leviathan
Creek) coming into contact with the minerals in the open pit, an abandoned adit, and overburden materials (ref.
4, p. 18). Each of these processes is discussed below. Figure 1 depicts the principal features of Leviathan Mine.
Leviathan Mine consists of a 50-acre open pit, approximately 2,000 feet long, 1,000 feet wide, and a maximum
of 400 feet deep (ref. 4, p. 6). Prior to the construction of the Pollution Abatement Project in the 1980s, the pit
drained internally except when rising ground water and accumulating surface water runoff flowed through a
breach on the west side of the pit into an unlined ditch and into Leviathan Creek (ref. 5, pp. 2-16, 2-31, 3-28).
The Pollution Abatement Project regraded and compacted the open pit to promote surface runoff and reduce
infiltration (ref. 4, p. 33). The bottom of the pit was raised above the “throat,” and reinforced concrete ditches
were constructed along regraded terraces to collect surface water runoff (ref. 4, p. 33). Subsurface drains were
installed in the bottom of the pit to intercept infiltrating precipitation before it enters the deeper underground mine
workings (ref. 4, pp. 32 to 33). The pit underdrain system discharges to the flow control structure and then to
one of the evaporation ponds (ref. 4, p. 31; ref. 6, p. 8). Surface water drainage from the pit currently flows
to Leviathan Creek in a concrete pipe; it is not directed to the evaporation ponds (ref. 4, p. 33).
Water also drains from the southern part of the open pit through Adit No. 5, one of the only remaining features
from the early underground sulfur mining efforts (ref. 4, p. 5; ref. 5, pp. 2-17 and 2-32). As ground water rises
in the southern part of the pit, it enters Adit No. 5 at its eastern terminus. It flows downhill through the adit and
emerges as a spring near the collapsed portal of this adit, on the west exterior wall of the mine pit (ref. 5, pp. 217 and 2-32). Prior to the construction of the Pollution Abatement Project, this flow joined with the drainage
from the pit in the unlined drainage ditch that discharged to Leviathan Creek (ref. 5, p. 3-28). Under current
conditions, flow from Adit No. 5 is diverted into the flow control structure and then to the evaporation ponds
constructed as part of the Pollution Abatement Project (ref. 4, p. 31).
Approximately 22 million tons of overburden containing large quantities of low-grade sulfur ore were spread over
more than 200 acres at the mine site (ref. 4, p. 6). Several million cubic yards were placed directly into the
Leviathan Creek channel (ref. 4, p. 6; ref. 7, p. 4; ref. 10, p. 4). Surface runoff from snowmelt and precipitation
comes into contact with this ore, becomes acidic, and leaches heavy metals and other substances from the ore
1
The Regional Water Quality Control Board, Lahontan Region, (RWQCB) contracted installation of a Pollution Abatement
Project between 1983 and 1985 (ref. 4, p. 27). The principal components of the project included filling and regrading the mine
pit, channelizing Leviathan Creek, constructing lined evaporation ponds to contain the AMD draining from the pit and adit, and
regrading and revegetating the overburden piles (ref. 4, pp. 30 to 33).
8
Source 1
(ref. 5, p. 4-6; ref. 7, p. 4). In addition to Leviathan Creek flowing over the mining wastes, numerous springs
and seeps emanate from the toe of the overburden piles and flow directly into Leviathan and Aspen creeks (ref.
10, pp. 20 and 21). A major component of the Pollution Abatement Project is the channelization of Leviathan
Creek to prevent creek waters from coming into contact with mine wastes dumped into the channel. By creating
a barrier between the creek and the mining waste, the channel prevents seepage from the creek through the waste
piles, thus decreasing the amount of AMD generated (ref. 4, p. 30). During construction of the Leviathan Creek
channel, several acidic springs with significant flow were discovered. Since the springs had not been factored
into the project design, they were directed into a drainage system running beneath the creek channel. The channel
underdrain discharges directly to Leviathan Creek at the lower end of the creek channelization (ref. 4, p. E-3).
Source Location
AMD emanates from the open pit, Adit No. 5, and springs and seeps along Leviathan Creek (ref. 4, p. 18).
Leviathan Creek flows south to north, west of the open pit and Adit No.5, through some of the overburden (see
Figure 1).
Source Containment
Gas Release to Air
The AMD at Leviathan Mine emanates from springs and seeps or flows on the surface of the open pit or
overburden. None of the features listed in Table 6-3 of the HRS applies to this source; therefore, a gas
containment factor value of 10 has been assigned (ref. 1, Table 6-3).
Particulate Release to Air
This source consists solely of the liquid AMD that results when water and air oxidize the sulfur minerals in the
mine; therefore, a particulate containment factor value of 0 has been assigned (ref. 1, Table 6-9).
Release to Ground Water
No liner beneath the AMD emanating from the mine restricts the reinfiltration to ground water; therefore, a
ground water containment factor value of 10 has been assigned (ref. 1, Table 3-2).
Release to Surface Water
Prior to the construction of the Pollution Abatement Project, the AMD from the open pit and the adit portal
flowed through a ditch directly into Leviathan Creek (ref. 5, p. 3-28). There are still springs emanating from the
overburden piles that flow into a drainage system under the channelized portion of Leviathan Creek and eventually
discharge into the creek (ref. 4, p. E-3). Because of this evidence of hazardous substance migration from source
area, the surface water containment factor value has been assigned a 10 (ref. 1, Table 4-2).
9
Source 1
A copy of Figure 1 is available at the EPA Headquarters Superfund Docket:
U.S. CERCLA Docket Office
Crystal Gateway #1, 1st Floor
1235 Jefferson Davis Highway
Arlington, VA 22202
Telephone: (703) 603-8917
E-Mail: superfund.docket@epa.gov
10
SD—Hazardous Substances
Source 1
2.4.1. Hazardous Substances
The U.S. Geological Survey (USGS) collected samples of AMD from the seep at the portal to Adit No. 5 and
drainage from the breach in the throat of the open pit on several occasions between March 1981 and February
1983 (ref. 10, pp. 25 to 28). The USGS refers to these sampling locations as sites 2 and 3. For clarity in this
evaluation, USGS sampling sites are called stations, not sites (i.e., Station 2 instead of Site 2). The samples for
dissolved major and trace constituents were filtered through a 0.45-micrometer pore-size filter and acidified in
the field (ref. 10, p. 23). The samples were analyzed by inductively coupled plasma spectroscopy (ICP) by the
USGS Central Laboratory in Arvada, Colorado (ref. 10, p. 9). Table 1 lists the dissolved concentrations of
hazardous substances in the AMD samples from the seep at Adit No. 5 (Station 2), the drainage from the open
pit (Station 3), and one of the seeps flowing from the overburden into Leviathan Creek (Station 5.5 or Station
6) (ref. 10, pp. 20, 28, and 55).
In addition to hazardous substances listed in 40 CFR 302.4, iron and sulfate are considered hazardous substances
for this evaluation because they meet the definition of "pollutant or contaminant" in CERCLA Section 101 (33).
The concentrations of iron and sulfate in the AMD are higher than the levels known to be detrimental to stock
and wildlife watering and to fish propagation (ref. 15, pp. IV-5 and IV-8).
The results presented in Table 1 represent the highest reported concentration for each hazardous substance. The
pH of the samples collected from the adit and pit drainage ranged between 1.8 and 2.8 (ref. 10, pp. 25 to 28).
The pH of the overburden seep samples was slightly higher, 2.9 to 3.6, but still acidic relative to the pH of the
uncontaminated water in Leviathan Creek upstream of the mine (pH 5.3 to 8.1) (ref. 10, pp. 24, 25, 28). Because
some of the AMD samples have pH values of less than 2, the AMD sometimes meets the criteria to classify it as
a D002 waste under the Resource Conservation and Recovery Act (RCRA).
Although the samples were collected in 1981 and 1982, they are representative of the hazardous substances
present in the AMD between 1962 and 1983, which defines Source 1. Anaconda ceased mining operations at the
site in late 1962 (ref. 4, p. 6). Until construction of the Pollution Abatement Project began in August 1983, the
only changes that occurred at the site pertained to rerouting Leviathan Creek around the waste dump (ref. 4, p.
27; ref. 5, pp. 2-4 and 2-5). No alterations were made that would have affected the quantity or quality of AMD
at the open pit, Adit No. 5, or the underflow seeps; therefore, the hazardous substances in the AMD samples
collected in 1981 and 1982 are reflective of the hazardous substances that would have been in the AMD during
the entire period of AMD generation.
Sample quantitation limits were not provided for the data in reference 10. Detection limits for the samples were
provided only for those samples in which the analyte was not detected (ref. 10, pp. 24 to 28).
11
Source 1
Table 1
Source 1 Hazardous Substances
Hazardous
Substance
Arsenic (µg/L)
Beryllium (µg/L)
Cadmium (µg/L)
Chromium (µg/L)
Cobalt (µg/L)
Copper (µg/L)
Manganese (µg/L)
Nickel (µg/L)
Thallium (µg/L)
Source Site
Sample Date
Concentration
Reference
2
4/23/82
8/11/82
30,000
30,000
ref. 10, p. 26
ref. 10, p. 27
3
3/26/82
25,000
ref. 10, p. 27
6
3/26/82
380
ref. 10, p. 28
2
4/23/82
21
ref. 10, p. 26
3
12/03/81
32
ref. 10, p. 27
6
3/26/82
16
ref. 10, p. 28
2
4/23/82
280
ref. 10, p. 26
3
3/26/82
270
ref. 10, p. 27
6
3/26/82
50
ref. 10, p. 28
2
3/26/82
2,200
ref. 10, p. 26
3
3/26/82
1,900
ref. 10, p. 27
6
3/26/82
300
ref. 10, p. 28
2
4/23/82
13,000
ref. 10, p. 26
3
3/26/82
10,000
ref. 10, p. 27
6
3/26/82
2,500
ref. 10, p. 28
2
4/23/82
22,000
ref. 10, p. 26
3
4/23/82
24,000
ref. 10, p. 28
6
3/26/82
3,200
ref. 10, p. 28
2
4/23/82
14,000
ref. 10, p. 26
3
12/3/81
27,000
ref. 10, p. 27
6
1/29/82
25,000
ref. 10, p. 28
2
4/23/82
15,000
ref. 10, p. 26
3
3/26/82
11,000
ref. 10, p. 27
6
1/29/82
8,000
ref. 10, p. 28
2
4/23/82
4,400
ref. 10, p. 26
3
3/26/82
1,300
ref. 10, p. 27
5.5
8/11/82
450
ref. 10, p. 28
12
Source 1
Table 1
Source 1 Hazardous Substances
Hazardous
Substance
Zinc (µg/L)
Iron (mg/L)
Sulfate (mg/L)
Source Site
Sample Date
Concentration
Reference
2
4/23/82
2,700
ref. 10, p. 26
3
3/26/82
2,400
ref. 10, p. 27
6
3/26/82
820
ref. 10, p. 28
2
4/23/82
2,700
ref. 10, p. 26
3
3/19/81
3,700
ref. 10, p. 27
6
11/12/81
1,100
ref. 10, p. 28
2
4/23/82
12,000
ref. 10, p. 26
3
5/15/81
3/26/82
11,000
11,000
ref. 10, p. 27
6
3/26/82
3,700
ref. 10, p. 28
µg/L = micrograms per liter
mg/L = milligrams per liter
13
SD—Hazardous Waste Quantity
Source 1
2.4.2 Hazardous Waste Quantity
Tier A: Hazardous Constituent Quantity
There is insufficient data to determine the hazardous constituent quantity of Source 1, AMD.
Hazardous Constituent Quantity Value: 0
14
Source 1
Tier B: Hazardous Wastestream Quantity
The Design Report for the Pollution Abatement Project presents various estimates of the volume of AMD needing
to be controlled. These estimates vary depending on how much regrading and compaction of the open pit surface
would be performed (ref. 5, p. 5-7). One of the treatment levels evaluated involved leaving the pit surface in its
original condition, except for the small area where the underdrain collection system would have been installed.
The underdrain would have collected underground flow from the pit and seepage from the adit. For this
treatment level, the Design Report estimated that 20.4 million gallons of AMD would have been generated annually
(ref. 5, p. 5-12). The estimate is used in this evaluation as the amount of AMD generated prior to construction
of the Pollution Abatement Project.
Anaconda ceased mining operations at the site in late 1962 (ref. 4, p. 6). Construction of the Pollution Abatement
Project began in August 1983 (ref. 4, p. 27). For the period prior to the Pollution Abatement Project, the
estimated volume of AMD released from the mine to Leviathan Creek is:
1963 through 1983 = 21 years X 20.4 million gallons per year = 428.4 million gallons
Regrading and compaction of the pit occurred between the end of 1983 and July 1985, when the evaporation
ponds began receiving the AMD from the open pit, adit seep, and some of the other seeps. As a result, the rate
of AMD generation likely dropped. The Design Report estimated that the volume of AMD generated annually
after the regrading and compaction of the "recommended project" would be 8.5 million gallons (ref. 5, pp. 5-11
and 7-3). Although modifications were made to the recommended project design, the surface preparation
features remained the same; therefore, the estimated volume of AMD generation should apply to the current mine
conditions (ref. 4, p. 19; ref. 5, p. 5-11). A 1991 report of current conditions at Leviathan Mine provides an
estimated annual volume of AMD from the pit and adit to be 8.1 million gallons (ref. 7, p. 16). No rationale is
provided on how this estimate is derived, but it is used in this evaluation because it is similar to the "recommended
project" design estimate. For the period from 1984 through June 1985, the estimated volume of AMD released
from the mine to Leviathan Creek is:
1984 through June 1985 = 1.5 years X 8.1 million gallons = 12.15 million gallons
for a total of 440.55 million gallons from 1963 through June 1985.
Applying the conversion of 200 gallons = 2,000 pounds and dividing the wastestream quantity in pounds by 5,000
produces a source hazardous wastestream quantity value of:
440.55 million gallons X (2,000/200) / 5,000 = 881,100 (ref. 1, Table 2-5)
Because the AMD generated from July 1985 to the present flows into the evaporation ponds, the waste quantity
for that time period has been evaluated under Source 2, Evaporation Ponds, not here.
Hazardous Wastestream Quantity Value: 881,100
15
Source 1
Tier C: Source Volume
Because the hazardous wastestream quantity was adequately determined for this source, source volume has been
assigned a 0 (ref. 1, Section 2.4.2.1.2).
Dimension of Source (yd3): 0
Volume Assigned Value: 0
16
Source 1
Tier D: Source Area
Because the hazardous wastestream quantity was adequately determined for this source, source area has been
assigned a 0 (ref. 1, Section 2.4.2.1.2).
Area of Source (ft2): 0
Area Assigned Value: 0
17
Source 1
Source Hazardous Waste Quantity
The source hazardous waste quantity for Source 1, AMD, has been derived under Tier B—hazardous
wastestream quantity, and is 881,100.
Source Hazardous Waste Quantity: 881,100
18
Source 2
SOURCE DESCRIPTION
2.2
Source Description: Source 2 — Lined Evaporation Ponds
Source Type — Surface Impoundment
The Pollution Abatement Project at Leviathan Mine includes five lined evaporation ponds with an approximate
capacity of 14 million gallons and a total surface area of 11.5 acres. Since construction was completed in July
1985, the evaporation ponds have received AMD from the adit, the pit underdrain system, and various drains
collecting springs and seeps (ref. 4, p. 31).
The AMD collection system works by gravity (ref. 8, p. 6). The upper ponds, 1, 2N, and 2S, receive AMD from
the flow control structure and, when they fill up, overflow into pond 3 (ref. 4, p. 31). Pond 3 receives flow
from the upper ponds and from seeps collected by an underdrain east of pond 1 (ref. 4, p. 31). Pond 4 receives
overflow from pond 3, from a drain below the south levee of pond 3, and from springs to the east and south of
pond 4 (ref. 4, p. 31).
The holding capacity of the five evaporation ponds is not sufficient to retain all AMD generated at the mine (ref.
7, pp. 16 and 19). During spring snow melt, an average of 3 million gallons of AMD discharge from the
evaporation ponds to Leviathan Creek each year (ref. 4, p. 49).
The levees surrounding the ponds are trapezoidal with a 12-foot-wide top, 3:1 slope on the water side, 2:1 slope
on the land side, and maximum height of 6 feet (ref. 4, p. 31). Ponds 1, 2N, 2S, and 3 are lined with 36-mil
Dynaloy and each have an individual leak detection system that consists of a branched drain constructed with
drainrock and liner that connects to a monitoring well (ref. 4, p. 31). Pond 4 has a 30-mil unreinforced polyvinyl
chloride (PVC) liner, but no leak detection system (ref. 4, p. 31).
Source Location
The evaporation ponds are west of the open pit (see Figure 1) (ref. 7, p. 12). Ponds 1, 3, and 4 are northeast
of the channelized section of Leviathan Creek, and ponds 2N and 2S are southwest of the channel (ref. 7, p. 12).
Source Containment
Gas Release to Air
The evaporation ponds were designed to collect AMD and allow it to evaporate (ref. 4, pp. 48 and 49). No
controls exist to prevent the release of gaseous hazardous substances to air; therefore, a gas containment factor
value of 10 has been assigned (ref. 1, Table 6-3).
Sulfuric acid is one of the components of AMD; therefore, the evaporation ponds do not just contain particulate
hazardous substances totally covered by liquids (ref. 5, p. 3-17). No controls exist to prevent the release of
particulate hazardous substances to air; therefore, a particulate containment factor value of 10 has been assigned
(ref. 1, Table 6-9).
19
Source 2
Ponds 1, 2N, 2S, and 3 appear to be surface impoundments with free liquids present and sound diking that is
regularly inspected and maintained with adequate freeboard (ref. 4, pp. 43 and 44; ref. 8, pp. 3 and 4). The
ponds are lined and have a functioning leachate control system (ref. 8, p. 4). Pond 4 is lined but does not have
a leachate collection system (ref. 8, p. 4). Although numerous ground water wells were installed during the
planning and design phases of the Pollution Abatement Project, ground water monitoring is not part of the
ongoing water quality monitoring program at the site (ref. 4, pp. 40 to 42). Because of their containment
features, ponds 1, 2N, 2S, and 3 have been assigned a ground water containment factor value of 9. An estimated
3 million gallons of AMD overflow from Pond 4 to Leviathan Creek during years of average precipitation (ref.
4, p. 32; ref. 7, p. 16). Samples of the pond overflow collected in the spring of 1993, 1994, 1995, and 1998
contained arsenic and nickel at concentrations that were orders of magnitude higher than water samples collected
from creeks in the area (ref. 18, pp. 13, 14, 17, 18; ref. 26, pp. 5, 8). The pond overflow represents hazardous
substance migration from the pond; therefore, Pond 4 has been assigned a ground water containment factor value
of 10 (ref 1, Table 3-2). The source, therefore, has been assigned a ground water containment factor value of
10.
An estimated 3 million gallons of AMD overflow from Pond 4 to Leviathan Creek during years of average
precipitation (ref. 4, p. 32; ref. 7, p. 16). Samples of the pond overflow collected in the spring of 1993, 1994,
1995, and 1998 contained arsenic and nickel at concentrations that were orders of magnitude higher than water
samples collected from creeks in the area (ref. 18, pp. 13, 14, 17, 18; ref.26, pp.5, 8). The pond overflow
represents hazardous substance migration from the pond; therefore, a surface water containment factor value
of 10 has been assigned (ref. 1, Table 4-2).
20
Source 2
Since 1984, RWQCB staff have reportedly conducted monthly water sampling from several surface water
stations, but the data made available for this evaluation indicate that monitoring program activities are not regularly
conducted (ref. 4, p. 42; ref. 18, pp. 13, 14, 17, 18). From August 1984 to February 1995, samples were
collected from the flow control structure that combined the adit discharge with the pit underdrain (ref. 18, pp.
1 and 4). Since February 3, 1995, separate samples were collected from the adit discharge and the pit underdrain.
These samples are only analyzed for sulfate, iron, arsenic, aluminum, nickel, and total dissolved solids (ref. 18,
pp. 7 to 18). It is not known if these are dissolved or total recoverable metals. Although only data summary
tables were available for this evaluation, the data presented in Table 2 show that samples collected from these
sampling sites contain concentrations of some hazardous substances at concentrations similar to the levels
contained in the AMD prior to the construction of the Pollution Abatement Project.
Table 2 contains the three highest concentrations in the combined adit and pit drainage from before February
1995 and all results available in the reference (February through October 1995) for the individual adit and pit
samples. The quality of the data are unknown and sample quantitation or detection limits were not provided;
however, the similarity in concentrations found in multiple samples over an 11-year period indicates that the data
are adequate to document the presence of arsenic, nickel, iron, and sulfate in Source 2. In addition, data from
RWQCB for 1997 and 1998 indicate that the concentrations of these hazardous substances in the adit and pit
drainage are substantially the same as measured during the 11-year period (ref. 26, pp. 5, 7, 8, 10).
Table 2
Source 2 Hazardous Substances (in mg/L)
Hazardous
Substance
Arsenic
Nickel
Sampling Date
Combined Adit and
Pit Drainage
Adit Drainage
Open Pit
Underdrain
Reference
5/25/86
22.9
18, p. 13
7/14/86
21.5
18, p. 13
8/15/86
34
18, p. 13
2/3/95
15
3.6
18, p. 14
3/8/95
14
5.3
18, p. 14
5/19/95
21
24
18, p. 14
6/22/95
28
22
18, p. 14
7/20/95
26
14
18, p. 14
8/17/95
28
35
18, p. 14
9/14/95
26
11
18, p. 14
7/14/86
8.6
18, p. 17
8/15/86
9.5
18, p. 17
5/18/93
8.8
18, p. 17
2/3/95
5.4
3.3
18, p. 18
3/8/95
6.6
3.9
18, p. 18
21
Source 2
Table 2
Source 2 Hazardous Substances (in mg/L)
Hazardous
Substance
Sampling Date
Combined Adit and
Pit Drainage
Sulfate
Open Pit
Underdrain
Reference
3/17/95
5.8
1.1
18, p. 18
5/19/95
8.2
8.9
18, p. 18
6/22/95
8.9
7.8
18, p. 18
7.1
18, p. 18
7/20/95
Iron
Adit Drainage
10
8/17/95
8.5
5.5
18, p. 18
9/14/95
9.5
4.0
18, p. 18
7/1/85
1,260
18, p. 11
5/18/93
1,300
18, p. 11
5/25/93
1,590
18, p. 11
2/3/95
760
660
18, p. 12
3/8/95
850
1,100
18, p. 12
5/19/95
2,400
2,100
18, p. 12
6/22/95
1,400
1,700
18, p. 12
7/20/95
1,200
1,400
18, p. 12
8/17/95
1,000
1,100
18, p. 12
9/14/95
1,100
1,100
18, p. 12
5/18/93
7,800
18, p. 9
6/28/93
5,900
18, p. 9
4/18/94
6,200
18, p. 9
2/3/95
5,700
4,300
18, p. 10
3/17/95
4,658
2,975
18, p. 10
4/25/95
6,982
9,640
18, p. 10
6/22/95
5,282
7,053
18, p. 10
7/20/95
3,816
6,229
18, p. 10
22
Source 2
There is insufficient data to evaluate the hazardous constituent quantity of Source 2—Lined Evaporation Ponds.
23
Source 2
Approximately 8.1 million gallons of AMD are generated every year at Leviathan Mine (ref. 7, p. 16). The AMD
is diverted to the flow control structure, which directs the flow to the various evaporation ponds (ref. 8, p. 2).
The Pollution Abatement Project construction was completed in 1985; therefore, the flow of AMD into the
evaporation ponds is assumed to have started in mid-1985 (ref. 4, p. 27). For the period from July 1985 through
1997, the estimated volume of AMD released from the mine to the evaporation ponds is:
July 1985 through 1997 = 12.5 years X 8.1 million gallons = 101.25 million gallons
Applying the conversion of 200 gallons = 2,000 pounds and dividing the wastestream quantity in pounds by 5,000
produces a source hazardous wastestream quantity value of:
101.25 million gallons X (2,000/200) / 5,000 = 202,500 (ref. 1, Table 2-5)
Hazardous Wastestream Quantity Value: 202,500
24
Source 2
In February 1999, a contractor reported to the U.S. EPA the following maximum capacity for the evaporation
pond system: 2,233,098 cubic feet (ref. 27, pp. 1, 5). Calculations were based on a 1984 aerial photographic
survey (conducted immediately after pond construction and before significant quantities of water entered the
system) and specifications taken from the construction drawings (ref. 27, p. 2). Applying the conversion factor
of 27 cubic feet = 1 cubic yard yields 82,707 cubic yards. Dividing this volume by 2.5 produces a source
volume value of :
2,233,098 cubic feet X (1/27) / 2.5 = 33,083 (ref. 1, Table 2-5)
Because Tier B—hazardous wastestream was adequately determined, the source volume value has been assigned
a 0 (ref. 1, Section 2.4.2.1.2).
Dimension of Source (yd3): 82,707
25
Source 2
Tier D: Source Area
In February 1999, a contractor reported to the U.S. EPA the following total surface area for the evaporation pond
system: 12.079 acres (ref. 27, pp. 1, 5). Calculations were based on a 1984 aerial photographic survey and
construction drawing for the ponds (ref. 27, p. 2). Applying the conversion of 43,560 square feet = 1 acre
yields 526,161 square feet = Dividing this area by 13 produces a source area value of:
12.079 acres X 43,560 / 13 = 40,473.9 (ref. 1, Table 2-5)
Because Tier B—hazardous wastestream was adequately determined, the source area value has been assigned
a 0 (ref. 1, Section 2.4.2.1.4).
Area of Source (ft2): 526,161
26
Source 2
The source hazardous waste quantity for Source 2, Lined Evaporation Ponds, was derived under Tier
B—hazardous wastestream quantity, and is 202,500.
Source Hazardous Waste Quantity: 202,500
27
Source 3
SOURCE DESCRIPTION
2.2
Source Description: Source 3 — Waste Overburden Piles
Source Type — Tailings Pile
Approximately 22 million tons of overburden containing large quantities of low-grade sulfur ore were spread over
more than 200 acres without any classification, separation, or original ground surface preparation. The
overburden piles are generally described as four separate areas: Spoil areas A, B, and C, and the waste dump (ref.
4, p. 6).
The spoil areas include areas covered to various depths by loosely dumped overburden and mine spoils that were
generated during excavation of the open pit. Some sulfur ore and other mineralized zones occur in the spoil areas
(ref. 5, p. 2-16). Spoil Area A lies along the west side of Aspen Creek, covering 103.6 acres to a depth of as
much as 142 feet (ref. 5, p. 2-16). The northern half of Spoil Area A covers much of the head of an active
landslide (ref. 5, p. 2-16). Spoil areas B and C cover 32.3 and 14.4 acres, respectively, along and to the east of
Leviathan Creek. In many locations, the spoils in areas B and C are just a veneer of loose earth materials
overlying bedrock, but the overburden reaches a maximum depth of about 40 feet in other locations (ref. 5, p.
2-16).
Anaconda created the waste dump by disposing of waste rock consisting of low-grade ore from the mining
operations into Leviathan Creek Canyon (ref. 4, p. 6). The waste dump covers 25.9 acres to a depth of up to
132 feet (ref. 5, p. 2-17). The waste dump materials contain a greater overall residual mineralization than the
spoil areas (ref. 5, p. 2-17).
Source Location
The overburden piles cover the central portion of the Leviathan Mine property (see Figure 1) (ref. 5, p. 2-16).
Source Containment
Gas Release to Air
Although regrading and revegetation of the overburden piles were components of the Pollution Abatement Project,
regrading did not involve uncontaminated cover material; therefore, adequate success with revegetation was not
achieved (ref. 4, p. 33; ref. 7, p. 1). No containment features would inhibit the migration of gaseous hazardous
substances to air; therefore, a gas containment factor value of 10 has been assigned (ref. 1, Table 6-3).
Although regrading and revegetation of the overburden piles were components of the Pollution Abatement Project,
regrading did not involve uncontaminated cover material; therefore, adequate success with revegetation was not
achieved (ref. 4, p. 33; ref. 7, p. 1). No containment features would inhibit the migration of particulate hazardous
substances to air; therefore, a particulate containment factor value of 10 has been assigned (ref. 1, Table 6-3).
28
Source 3
Anaconda spread the overburden from the open pit mining operations over more than 200 acres without any
classification, separation, or original ground surface preparation (ref. 4, p. 6). A ground water containment
factor value of 10 has been assigned for "no liner" (ref. 1, Table 3-2).
Anaconda created the waste dump by disposing of waste rock directly into Leviathan Creek (ref. 4, p. 6).
Although the overburden piles were regraded to reduce the ponding and infiltration of precipitation, evidence of
continued erosion indicates that there is no maintained, engineered cover on the waste piles, nor is there a
complete runon/runoff control system over all of the piles (ref. 7, p. 9 and 17). A surface water containment
factor value of 10 has been assigned (ref. 1, Table 4-2).
29
Source 3
The history of mining activities at Leviathan Mine provides the only information on the presence of hazardous
substances in the overburden.
In 1863, miners identified the mine as a potential source of chalcanthite, a mineral composed of copper sulfate
(CuSO4•5H20). This early exploration found chalcanthite as coatings, seams, and cavity fillings rather than as
a concentrated ore. The miners gave up on the chalcanthite, but pursued extraction of primary copper minerals
found in the area. By 1870, reports indicated that 500 tons of 30 to 50 percent copper ore had been removed.
In 1872, reports still raved about the high-grade copper ore, but also mentioned that the mine was "bottoming"
in sulfur (ref. 12, p. 35).
From 1935 to 1941, the Calpine Corporation operated an experimental plant for the recovery of sulfur by steam
liquidation. About 5,000 long tons of sulfur were produced from underground workings (ref. 12, p. 35).
The Anaconda Company purchased the property in 1951 to develop an open pit mine. The stripping of the
overburden was done in 1952 and early 1953; open pit mining of the sulfur ore began in July 1953 (ref. 12, p.
36). With the exception of Adit No. 5, all of the older mine workings were apparently destroyed during the
stripping of the overburden (ref. 5, p. 2-17; ref. 13, p. 2).
Based on these historical activities, it can be concluded that copper and sulfur, once mined from underground
workings, are present in the overburden that was removed to get to the sulfur ore mined by open pit.
30
Source 3
There is insufficient data to determine the hazardous constituent quantity for Source 3.
31
Source 3
An industry report from 1955 of the mining activity at Leviathan stated that 22 million tons of overburden were
removed to get to the sulfur ore (ref. 14, p. 176). Subsequent discussions of the mine all use 22 million tons as
the quantity of overburden removed and placed to the sides of the open pit (ref. 4, p. 6; ref. 5, p. 2-2; ref. 9, p.
6).
Applying the Tier B divisor of 5,000 to 22 million tons of wastestream produces a hazardous wastestream
quantity value of:
22 million tons x 2,000 pounds/ton / 5,000 = 8.8 million (ref. 1, Table 2-5)
Hazardous Wastestream Quantity Value: 8.8 million
32
Source 3
There is insufficient information to determine the source volume.
Dimension of Source (yd3): 0
33
Source 3
Tier D: Source Area
The Design Report for the Pollution Abatement Project provides the plan surface area for spoil areas A, B, and
C, and the waste dump (ref. 5, pp. 2-16 and 2-17):
Spoil Area A
Spoil Area B
Spoil Area C
Waste Dump
103.6 acres
32.3 acres
14.4 acres
25.9 acres
Total area
176.2 acres
2
Converting the area in acres to feet and dividing by the Tier D divisor for "pile" produces a source area value
of:
2
176.2 acres x 43,560 ft /acre /13 = 590,405.54 (ref. 1, Table 2-5)
Because Tier B—hazardous wastestream was adequately determined, the source volume value has been assigned
a 0 (ref. 1, Section 2.4.2.1.2 and 2.4.2.1.4).
Area of Source (ft2): 7,675,272
34
Source 3
The source hazardous waste quantity for Source 3, Overburden Piles, was derived by Tier B—hazardous
wastestream quantity, and is 8.8 million.
Source Hazardous Waste Quantity: 8.8 million
35
Source Description-Summary
SITE SUMMARY OF SOURCE DESCRIPTIONS
Source Number
Source Hazardous
Waste Quantity
Value
Containment
Ground Water
Surface Water
Air Gas/Particulate
1
881,100
10
10
10/0
2
202,500
10
10
10/10
3
8.8 million
10
10
10/10
36
GW—General
GROUND WATER MIGRATION PATHWAY
3.0.1 General Considerations
The hydrogeologic conditions at Leviathan Mine have been examined in detail because of the role that ground
water flow plays in the formation of AMD (ref. 10, p. 5). The acidic and mineralized ground water surfaces as
springs and seeps before flowing into Leviathan Creek. The nearest wells used for domestic or livestock supply
exist 4 to 5 miles east of the mine (ref. 9, p. 35). Because ground water is not used within 4 miles of the mine,
the ground water migration pathway was not scored.
37
SW—Pathway Description
SURFACE WATER MIGRATION PATHWAY
4.1 OVERLAND/FLOOD MIGRATION COMPONENT PATHWAY DESCRIPTION
4.1.1
General Consideration
4.1.1.1
Definition of Hazardous Substance Migration Path for Overland/Flood Component
Leviathan Mine drains to Leviathan Creek, a major tributary of the 31.5-square-mile Bryant Creek watershed (ref.
9, p. 17). From its headwaters at Leviathan Peak, Leviathan Creek flows northward for about 2 miles before
traversing Leviathan Mine, and then another 2.5 miles to its confluence with Mountaineer Creek to form Bryant
Creek (ref. 9, pp. 17 and 18). Aspen Creek drains the southern portion of the mine site and enters Leviathan
Creek about 1 mile upstream from the confluence of Leviathan and Mountaineer creeks (ref. 3). From the
confluence of Leviathan and Mountaineer creeks, Bryant Creek flows 4 miles northwest to the California-Nevada
border and another 3.5 miles to its confluence with the East Fork Carson River, a major western Nevada water
supply source (ref. 9, pp. 1, 18).
There are numerous probable point of entries (PPEs) for the sources at Leviathan Mine. Some of the PPEs
existed prior to the construction of the Pollution Abatement Project, some were formed by the construction of
the Pollution Abatement Project, and others have been unchanged by the project. The PPEs have been combined
by general proximity into three main PPEs identified on Figure 1:
PPE 1 represents:
C The discharge point for the channel underdrain, which collects AMD from seeps that entered
Leviathan Creek before it was channelized (part of Source 1) (ref. 4, p. 30).
C The discharge point for the Pond 4 overflow (Source 2) (ref. 6, pp. 8 and 13).
PPE 2 represents:
C The point where Source 1, the AMD from the open pit and Adit No. 5 prior to the construction of
the Pollution Abatement Project, drained into Leviathan Creek (designated by Station 9 on Figure 1)
(ref. 10, p. 6).
C The furthest downstream location where Leviathan Creek travels over Spoil Area B (part of Source
3) (ref. 10, p. 3).
PPE 3 represents the length of Aspen Creek that traverses Spoil Area A (part of Source 3) on the northeast side
of the site (ref. 4, p. 7).
Reports of a fish kill in the East Fork Carson River document an observed release by direct observation (see
Section 4.1.1.2 below) which in turn extends the target distance limit (TDL) for the surface water pathway.
In November 1959, the dikes of a pond created to hold back AMD for treatment broke and an estimated 5 million
gallons of "highly acidic and toxic waste" discharged into Leviathan Creek. Reports state that aquatic life was
destroyed along a 10-mile stretch of the Carson River, beginning where Bryant Creek flows into the river (ref.
5, pp. 2-3 and 2-4; ref. 15, p. III-6). The in-water segment of the surface water pathway consists of
approximately 20 miles from the most upstream PPE (PPE 1) to the TDL (see Figure 2).
38
A copy of Figure 2 is available at the EPA Headquarters Superfund Docket:
U.S. CERCLA Docket Office
Crystal Gateway #1, 1st Floor
1235 Jefferson Davis Highway
Arlington, VA 22202
Telephone: (703) 603-8917
E-Mail: superfund.docket@epa.gov
39
4.1.1.2 Observed Release
An observed release to surface water can be documented by direct observation and by chemical analyses.
Direct Observation
As described below, an observed release of hazardous substances to Leviathan Creek can be documented by
direct observations in three ways: direct discharge of AMD to the creek, disposal of overburden directly into
the creek channel, and two fish kills related to releases of AMD from the mine.
Direct Discharge of AMD to Leviathan Creek
As discussed below, AMD generated at the mine (Source 1), which contained hazardous substances, discharged
directly into Leviathan Creek, both before and after the Pollution Abatement Project was constructed at Leviathan
Mine. Because the discharge contains hazardous substances, it establishes an observed release by direct
observation (ref. 1, Section 4.1.2.1.1).
Prior to completion of the Pollution Abatement Project in 1985, AMD that emanated from the open pit and Adit
No. 5 flowed through a ditch and discharged directly into Leviathan Creek (ref. 5, pp. 3-28 and 3-29; ref. 15,
p. IV-15, VI-3; ref. 16, p. 2; ref. 17, p. 1).
The Pollution Abatement Project at Leviathan Mine produced five lined evaporation ponds that receive the AMD
from the adit, the pit underdrain system, and various drains collecting springs and seeps (ref. 4, p. 31). The
holding capacity of the five evaporation ponds is not sufficient to retain all AMD generated at the mine (ref. 7,
pp. 16 and 19). During spring snow melt, an average of 3 million gallons of AMD discharge from the
evaporation ponds to Leviathan Creek each year (ref. 4, p. 49). During these times, the waters of the creeks
appear turbid and orange-colored, and the substrate becomes covered with yellow-orange precipitates. The
visibly turbid water and precipitates sometimes reach as far downstream as the East Fork Carson River, where
plumes of yellow-orange water and sediment have been seen along the side of the river downstream of inflow
from Bryant Creek (ref. 23, p. 4). The U.S. Geological Survey collected samples of AMD from the seep at the
portal to Adit No. 5 (Station 2) and drainage from the breach in the throat of the open pit (Station 3) on several
occasions between March 1981 and February 1983 (ref. 10, pp. 25 to 28). Table 1, provided in the Source
Description for Source 1, lists the dissolved concentrations of hazardous substances in the AMD samples from
the seep at Adit No. 5 (Station 2), the drainage from the open pit (Station 3), and one of the seeps flowing from
the overburden into Leviathan Creek (Station 5.5 or 6) (ref. 10, pp. 20, 28, and 55).
Direct Disposal of Overburden into the Leviathan Creek Channel
Hazardous substances were also directly deposited into Leviathan Creek by the disposal of overburden containing
copper and sulfur ore into the Leviathan Creek channel (ref. 4, p. 6; ref. 5, pp. 2-2 and 2-3; ref. 7, p. 4; ref. 10,
p. 4; ref. 12, p. 35; ref. 13, p. 2). Overburden removed from the pit for access to sulfur ore was dumped
directly into Leviathan Creek Canyon, damming the creek waters and causing them to percolate through and flow
around the waste dump area (ref. 15, p. I-1).
Fish Kills
Additional direct observation of an observed release of hazardous substances to surface water comes from
reports of two fish kills resulting from the release of AMD from the mine (ref. 5, p. 2-34). In 1952, a fish kill
occurred in Bryant Creek and the East Fork Carson River (10 miles downstream from the mine) when an old
mine shaft was opened, discharging a large quantity of "highly acidic and toxic waste" into Leviathan Creek (ref.
15, p. III-2). In November 1959, the dikes of a pond created to hold back AMD for treatment broke and an
estimated 5 million gallons of "highly acidic and toxic waste" discharged into Leviathan Creek. Reports state that
aquatic life was destroyed along a 10-mile stretch of the Carson River, which starts 10 miles downstream from
the mine (ref. 5, pp. 2-3 and 2-4; ref. 15, p. III-6). Anaconda paid the Nevada Fish and Game Commission for
40
replanting trout in the Carson River, but denied that the discharge had any serious effect on the stream (ref. 15,
p. III-6).
Chemical Analysis
Three sets of analytical data exist that demonstrate that an observed release of hazardous substances has occurred
to Leviathan and Bryant creeks. The quality of the data in these data sets is not known or documented as
required for use establishing an observed release; however, together, the data sets show a trend that the water
of Leviathan and Bryant creeks below the mine contains significantly higher concentrations of several hazardous
substances than the water of Leviathan Creek upstream from the mine.
Regional Water Quality Control Board (RWQCB) Data—1968 to 1969
Data collected by the RWQCB in 1968 and 1969 document that arsenic, copper, manganese, iron, and sulfates
were present in samples collected from Leviathan Creek below the discharge of AMD, and from Bryant Creek
at the point of diversion for the Park Ranch (about 8.5 miles downstream from the mine) in concentrations at
least three times the concentration in samples collected upstream of the mine. Table 3 lists these sample
concentrations as summarized in a 1975 RWQCB report (ref. 15, pp. IV-3 to IV-9).
Table 3
1968 and 1969 Data Documenting an Observed Release to
Leviathan and Bryant Creeks (in mg/L)
Station
Date
Upstream above discharge
12/5/68
0.01
0.04
<0.01
0.20
6/12/69
0.01
0.02
<0.01
0.26
9/22/69
<0.01
<0.01
<0.05
0.28
12/5/68
NR
2.0
4.0
112
6/12/69
1.2
1.8
<0.01
115
9/22/69
0.76
0.40
13.0
342
12/5/69
0.09
0.11
0.10
92
6/12/69
0.10
0.09
<0.01
32
9/22/69
0.20
0.05
0.61
34
IV-9
IV-7
IV-8
IV-8
Below discharge
Point of diversion
As
Reference 15, page
Cu
Key:
As, arsenic; Cu, copper; Mn, manganese; Fe, iron.
mg/L = milligrams per liter
NR = not reported
Underlined and italicized values represent an observed release.
41
Mn
Fe
USGS Data—1981 to 1983
Early attempts to develop pollution control measures identified a need for a more reliable and useful database of
water quality data (ref. 4, p. 16), so the RWQCB arranged to have the USGS conduct an extensive sampling
program on Leviathan and Bryant creeks from 1981 to 1983. Surface water samples were collected from 49
stations in the watershed, including samples of mine drainage, seeps, and water from Leviathan, Aspen, and
Bryant creeks (ref. 10, p. 20 and 21). The samples for dissolved major and trace constituents were filtered
through a 0.45-micrometer pore-size filter and acidified in the field (ref. 10, p. 23). The samples were then
analyzed by inductively coupled plasma spectroscopy (ICP) by the USGS Central Laboratory in Arvada, Colorado
(ref. 10, p. 9). Data from stations 2, 3, 5.5, and 6 are presented in Table 1 to document the presence of
hazardous substances in AMD. The creek sampling stations relevant to documenting an observed release to
surface water are as follows (ref. 10, pp. 20 and 21):
Background sampling stations:
1
7
11
Leviathan Creek above Leviathan Mine
Intermittent stream along northwest side of Leviathan Mine tailings dump
Eastward-draining stream (informally known as 4-L Creek)
Contaminated sampling stations:
8
10
12
15
17
25
26
Leviathan Creek at north end of delta below inflow from Station 7 (demonstrates impact of creek
flowing over waste dump)
Leviathan Creek below inflow from pit and tunnel (demonstrates impact of AMD inflow from open
pit and Adit No. 5)
Leviathan Creek above south side of slide and below summer diversion of pit and tunnel (same as
10)
Leviathan Creek above Aspen Creek (demonstrates creek condition before dilution from Aspen
Creek)—not presented in Table 3, but used as part later RWQCB monitoring network
Leviathan Creek below Aspen Creek (demonstrates dilution affect of Aspen Creek)
Bryant Creek below confluence of Leviathan and Mountaineer creeks (demonstrates dilution effects
of Mountaineer Creek)—not presented in Table 3, but used as part of later RWQCB monitoring
network
Bryant Creek above Doud Creek (farthest documented migration of hazardous substances) (ref.
10, pp. 20 and 21)
Data from stations 1, 7, 11, 8, 10, 12, 17, and 26 are presented in Table 4 to document an observed release to
surface water (ref. 10, pp. 25, 30 to 33, 35, 38, and 39).
RWQCB Data—1984 to 1995
RWQCB staff reportedly conduct monthly water sampling from several surface water stations, but the data made
available for this evaluation indicate that monitoring program activities are not regularly conducted (ref. 4, p. 42;
ref. 18, pp. 13, 14, 17, 18). The creek sampling stations are identified by the same station numbers used by the
USGS in its 1981 to 1983 data (ref. 10, pp. 20 and 21; ref. 18, pp. 1 and 2). The samples are only analyzed for
sulfate, iron, arsenic, aluminum, nickel, and total dissolved solids (ref. 18, pp. 7 to 18). It is not known if these
are dissolved or total recoverable metals. Although only data summary tables were available for this evaluation,
the data show that samples collected on the following dates from stations 8, 15, 17, and 25 contained arsenic
significantly above the concentration in the sample from Station 1 (as defined in ref. 1, Table 2-3):
42
Table 4
Surface Water Samples Documenting an Observed Release of Hazardous Substances to
Leviathan and Bryant Creeks, Spring and Summer 1982
Sample
Station and
Date
Dissolved Constituents (in milligrams/liter)
As
Be
Cd
Cr
Co
Cu
Ni
V
Zn
Ref.
Background Samples
1
3/26/82
0.009
<0.001
NR
<0.010
<0.003
<0.010
0.100
<0.006
0.004
10, p. 25
8/11/82
0.004
<0.001
<0.001
<0.010
<0.003
<0.010
<0.100
0.006
0.008
10, p. 25
3/25/82
0.003
0.001
<0.001
<0.010
<0.003
0.020
0.100
<0.006
0.006
10, p. 30
11 3/25/82
0.006
<0.001
<0.001
<0.010
<0.003
NR
0.100
<0.006
0.007
10, p. 32
7
Contaminated Samples
8
3/25/82
0.034
0.003
0.006
0.050
0.320
0.510
0.700
0.015
NR
10, p. 31
8/11/82
0.040
NR
NR
0.090
NR
NR
2.400
NR
NR
10, p. 31
10 3/25/82
1.700
0.004
0.025
0.200
0.660
1.400
1.400
0.160
0.300
10, p. 31
8/12/82
0.038
NR
NR
0.070
NR
NR
2.200
NR
NR
10, p. 32
12 3/24/82
1.400
0.004
0.019
0.160
0.470
1.200
1.200
0.120
0.260
10, p. 33
8/12/82
0.001
NR
NR
0.140
NR
NR
2.300
NR
NR
10, p. 33
17 3/24/82
0.600
0.003
0.012
0.120
0.380
0.880
0.900
0.050
0.190
10, p. 35
8/11/82
0.064
NR
NR
0.050
0.050
NR
0.900
NR
NR
10, p. 35
26 3/24/82
0.130
0.001
0.003
<0.010
0.120
0.240
0.300
<0.006
0.057
10, p. 38
8/20/82
0.003
0.002
<0.001
0.070
0.170
0.300
0.500
<0.006
0.088
10, p. 39
Key:
As, arsenic; Be, beryllium; Cd, cadmium; Cr, chromium; Co, cobalt; Cu, copper; Ni, nickel; V, vanadium; Zn, zinc
NR = not reported
Station numbers (except for Station 26) shown on Figure 1.
43
7/14/86, 3/30/88, 5/18/89, 4/7/93, 5/18/93, 6/28/93, and 3/11/94 (ref. 18, p. 13, 14)
The same data indicate that samples collected on the following dates from the same four stations contained nickel
in concentrations that exceeded the sample quantitation limit for nickel in samples from Station 1; none of the
samples from Station 1 contained detectable concentrations of nickel:
9/18/86, 3/30/88, 10/21/88, 5/18/89, 7/7/89, 8/23/91, 4/7/93, 6/28/93, 9/8/93, 3/11/94, 4/18/94, and
6/23/94 (ref. 18, pp. 17 and 18).
Samples from the same four stations contained sulfate at more than three times the concentration in the sample
from Station 1 on the following dates:
8/1/84, 10/2/84, 11/16/84, 7/1/85, 9/3/85, 11/1/85, 5/28/86, 9/18/86, 6/10/87, 7/21/87, 8/21/87, 10/6/87,
3/30/88, 6/2/88, 8/1/88, 10/21/88, 5/18/89, 7/7/89, 8/14/89, 12/27/89, 8/23/91, 10/31/91, 5/18/93, 6/28/93,
9/8/93, 3/11/94, 4/18/94, 6/23/94, and 7/20/95 (ref. 18, pp. 9 and 10).
Samples from the same four stations contained iron at more than three times the concentration in the sample from
Station 1 on the following dates:
8/1/84, 10/2/84, 11/16/84, 7/1/85, 9/3/85, 11/1/85, 5/28/86, 7/14/86, 8/15/86, 9/18/86, 10/20/86, 8/21/87,
10/6/87, 3/30/88, 6/2/88, 8/1/88, 10/21/88, 5/18/89, 7/7/89, 10/31/91, 5/18/93, 6/28/93, 6/23/94, and
9/14/95 (ref. 18, pp. 11 and 12).
Attribution
The analytical data discussed above show elevated concentrations of arsenic, beryllium, cadmium, chromium,
cobalt, copper, nickel, vanadium and zinc in Leviathan and Bryant creeks. The release of these hazardous
substances can be attributed to the Leviathan Mine site because, with the exception of vanadium2, these
substances have been documented in Source 1, AMD discharged prior to 1983, which discharged directly into
Leviathan Creek (ref. 5, pp. 3-28 and 3-29; ref. 15, p. IV-15, VI-3; ref. 16, p. 2; ref. 17, p. 1). The
concentrations of hazardous substances in Sources 1 and 2 are significantly higher than the concentration of
hazardous substances in Leviathan Creek both upstream and downstream of the mine (see Tables 1, 2, and 4).
In addition, there are no other known sources for the elevated hazardous substances in the watershed. Leviathan
Creek upstream from the mine site supports a fishery and other aquatic life typical of unpolluted streams in the
eastern Sierra Nevada (ref. 10, p. 4). Most of the Leviathan/Bryant Creek watershed resides on U.S. Forest
Service land. Cattle grazing is the predominant land use in the watershed (ref. 9, p. 34). No other mines,
historical or active, are identified within the watershed (ref. 3; ref. 9, p. 34).
2
Vanadium was not listed as a hazardous substance present in Source 1 because the specific form of vanadium present in the
AMD is not known and only those elements identified in 40 CFR 302.4 by the generic term “element and its compounds” were
evaluated as hazardous substances in Source 1.
44
SW-Drinking Water Threat
4.1.2
Drinking Water Threat
4.1.2.1 Likelihood of Release
Observed releases of arsenic, beryllium, cadmium, chromium, cobalt, copper, manganese, nickel, thallium, zinc,
iron, and sulfate to Leviathan Creek have been documented by direct observation (ref. 10, pp. 26 to 28).
Observed releases of hazardous substances to Bryant Creek and the East Fork Carson River have also been
documented by direct observation (ref. 5, pp. 2-3 and 2-4; ref. 15, pp. III-2 and III-6). An observed release of
arsenic, beryllium, cadmium, chromium, cobalt, copper, nickel, and zinc to Leviathan and Bryant creeks has been
documented by chemical analysis (ref. 10, pp. 25, 30, 31, 32, 33, 35, 38, 39; ref. 15, pp. IV-3 to IV-9; pp. 9
to 12, 17 and 18).
Likelihood of Release Factor Category Value: 550
45
SW-Drinking Water Threat
4.1.3.2 Waste Characteristics
4.1.3.2.1 Toxicity/Persistence Factor
Table 5
Drinking Water Threat Waste Characteristics
Hazardous
Substance
Arsenic
Persistence
(River)
Toxicity
Factor Value
Reference
1,2
10,000
1
10,000
B-2
Beryllium
1
10,000
1
10,000
B-3
Cadmium
1
10,000
1
10,000
B-4
Chromium
1
10,000
1
10,000
B-5
Cobalt
1
1
1
1
B-6
Copper
1,3
NA
1
---
B-6
1
10,000
1
10,000
B-13
1,2
10,000
1
10,000
B-14
Thallium
1
100
1
100
B-18
Zinc
1
10
1
10
B-20
Iron
1,2
1
1
1
B-12
1,2,3
1,000
0.4
400
B-18
Manganese
Nickel
Sulfur/Sulfate1
1
Source
Attribution
Factors for sulfuric acid reported.
4.1.2.2.2 Waste Quantity
The hazardous waste quantities assigned from Section 2.4.2 are:
881,100 + 202,500 + 8,800,000 = 9,883,500
The hazardous waste quantity factor value assigned for the drinking water threat is 1,000,000 (ref. 1, Table 2-6).
4.1.2.2.3 Waste Characteristics Factor Category Value
Multiplying the toxicity/persistence factor value for cadmium of 10,000 by the hazardous waste quantity factor
10
8
value of 1,000,000 equals 1 x 10 . This value is subject to a maximum of 1 x 10 and has received a waste
characteristics factor category value of 100 for the drinking water threat (ref.1, Table 2-7).
Waste Characteristics Factor Category Value: 100
46
SW-Human Food Chain Threat
Targets
4.1.2.3
Drinking Water Threat Targets
4.1.2.3.1
Nearest Intake
Neither Leviathan Creek nor Bryant Creek provides drinking water supplies (ref. 5, p. 3-2). The East Fork
Carson River does not appear to have a drinking water intake within 5 miles downstream of the inflow of Bryant
Creek (ref. 25, p. 3).
4.1.2.3.2
Population
No drinking water intakes are within the 15-mile target distance limit; therefore, a drinking water population
factor value of 0 has been assigned (ref. 1, Section 4.1.2.3.2).
4.1.2.3.3
Resources
Bryant Creek is diverted for irrigation and livestock watering just upstream from the confluence with the East
Fork Carson River (ref. 4, p. 11; ref. 5, p. 3-2; ref. 17, p. 2). A resources factor value of 5 has been assigned
(ref. 1, Section 4.1.2.3.3).
Drinking Water Target Factor Category Value: 5
Drinking Water Treat Score: 3.33
47
4.1.3
Human Food Chain Threat
4.1.3.1 Likelihood of Release
Observed releases of hazardous substances to Bryant Creek and the East Fork Carson River have also been
documented by direct observation (ref. 5, pp. 2-3 and 2-4; ref. 15, pp. III-2 and III-6). Observed releases of
arsenic, beryllium, cadmium, chromium, cobalt, copper, nickel, and zinc to Leviathan and Bryant creeks have
been documented by chemical analysis (ref. 10, pp. 25, 30, 31, 32, 33, 35, 38, 39; ref. 15, pp. IV-3 to IV-9; pp.
9 to 12, 17 and 18).
48
4.1.3.2 Waste Characteristics
4.1.3.2.1 Toxicity/Persistence/Bioaccumulation Factor
Table 6
Human Food Chain Threat Waste Characteristics
Hazardous
Substance
Source
Attribution
Arsenic
Beryllium
Persistence
(River)
Bioaccumulation
(Freshwater)
Factor
Value
Reference
1,2
10,000
1
5.0
50,000
B-2
1
10,000
1
50.0
500,000
B-3
7
Cadmium
1
10,000
1
5,000
5 x 10
Chromium
1
10,000
1
5
50,000
B-5
Cobalt
1
1
1
0.5
0.5
B-6
Copper
1,3
NA
1
50,000
---
B-6
1
10,000
1
0.5
5,000
B-13
1,2
10,000
1
0.5
5,000
B-14
Thallium
1
100
1
500
50,000
B-18
Zinc
1
10
1
500
5,000
B-20
Iron
1,2
1
1
0.5
0.5
B-12
1,2,3
1,000
0.4
0.5
200
B-18
Manganese
Nickel
Sulfur/Sulfate
1
Toxicity
1
B-4
881,100 + 202,500 + 8,800,000 = 9,883,500
The hazardous waste quantity factor value assigned for the human food chain threat is 1,000,000 (ref. 1, Table
2-6).
49
4.1.3.2.3 Waste Characteristics Factor Category Value
Multiplying the toxicity/persistence factor value for cadmium of 10,000 by the hazardous waste quantity factor
10
8
8
value of 1,000,000 equals 1 X 10 . This value is subject to a maximum of 1 x 10 , so 1 x 10 is multiplied by
11
the bioaccumulation factor of cadmium of 5,000 to produce 5 x 10 (ref. 1, Section 4.1.3.2.3). This value
receives a waste characteristics factor category value of 560 for the human food chain threat (ref. 1, Table 2-7).
Waste Characteristics Factor Category Value: 560
50
Targets
4.1.3.3
Human Food Chain Threat Targets
Leviathan Creek near Leviathan Mine supported a healthy trout fishery before the beginning of open pit mining
(ref. 6, p. 2; ref. 13, p. 6; ref. 19, p. 1; ref. 20, p. 1). Since 1954, the portion of the stream, from the mine to
near the confluence with the East Fork Carson River, has been devoid of fish (ref. 20, pp. 2 and 3; ref. 15, p.
VIII-1; ref. 21, p. 3). Even though fish do not currently reside in Leviathan and Bryant creeks downstream of
the mine, the entire in-water segment has been evaluated as a fishery because the AMD from Leviathan Mine
resulted in the destruction of the fishery (ref. 20, p. 3).
Surface water samples collected in 1981 to 1983 document actual contamination of Leviathan and Bryant creeks
as far downstream as Station 26 (see Table 4 and Figure 2). These water samples can be used to document
Level II concentrations, because at least one of the hazardous substances in the observed release has a
bioaccumulation factor of 500 or greater (ref. 1, Section 4.1.3.3). No fish tissue data are available to evaluate
the area under Level I concentrations.
In addition, Level II actual contamination extends the rest of the way down Bryant creek and 10 miles along the
East Fork Carson River because of the fish kills that resulted from releases from the mine. In November 1959,
the dikes of a pond created to hold back AMD for treatment broke and an estimated 5 million gallons of "highly
acidic and toxic waste" discharged into Leviathan Creek. Reports state that aquatic life was destroyed along a
10-mile stretch of the Carson River (ref. 5, pp. 2-3 and 2-4; ref. 15, p. III-6). Because the fish kill occurred
along the 10-mile stretch, as compared to being documented at a single point 10 miles downstream, the entire
10 miles downstream from the inflow of Bryant Creek is evaluated as subject to Level II concentrations.
4.1.3.3.1 Food Chain Individual
Observed releases of cadmium, copper, thallium, and zinc—hazardous substances with a bioaccumulation factor
of 500 or greater—have been documented in Leviathan Creek, a fishery (see Section 4.1.1.2); therefore, Level
II contamination has been assigned to the fishery, and a food chain individual factor value of 45 has been
assigned (ref. 1, Section 4.1.3.3.1).
4.1.3.3.2 Population
In 1969, the California Department of Fish and Game estimated the annual yield of trout in the 5.9-mile segment
of Leviathan and Bryant creeks within California to be 171 pounds (ref. 20, p. 6). As noted above, Leviathan and
Bryant creeks are both subject to Level II concentrations. A human food chain population value of 0.3 has been
assigned for this production (ref. 1, Table 4-18). Extrapolating the fishery production for the remainder of
Bryant Creek and the East Fork Carson River would not provide a larger population value.
4.1.3.3.3 Targets Factor Category Value
Summing the human hood chain individual factor value and the population factor value produce a targets factor
category value of 45.3.
Food Chain Individual: 45
Human Food Chain Targets Factor Category Value: 45.3
Human Food Chain Threat Score: 100
51
SW-Environmental Threat
4.1.4 Environmental Threat
4.1.4.1
Observed releases of arsenic, beryllium, cadmium, chromium, cobalt, copper, nickel, and zinc to Leviathan and
Bryant creeks have been documented by chemical analysis (ref. 10, pp. 25, 30, 31, 32, 33, 35, 38, 39; ref. 15,
pp. IV-3 to IV-9; pp. 9 to 12, 17 and 18).
Evidence also indicates that the observed release extends into the East Fork Carson River. The fish kills reported
in 1952 and 1959 resulting from the release of slugs of AMD from the mine to Leviathan Creek impacted the
surface water down to, and including, the East Fork Carson River (ref. 5, pp. 2-3, 2-4 and 2-34; ref. 15, pp. III2 and III-6). Reports state that the 1959 release destroyed aquatic life along a 10-mile stretch of the Carson
River (ref. 5, pp. 2-3 and 2-4; ref. 15, p. III-6). In 1969, biologists from California and Nevada observed
discolored water and sediment in the East Fork Carson River at the mouth of Bryant Creek, and found that
bottom fauna had been adversely impacted by inflow from Bryant Creek (ref. 23, p. 14). Subsequent to the
construction of the Pollution Abatement Project, turbid water and yellow-orange precipitates have been observed
entering the East Fork Carson River during spring runoff, when the evaporation ponds are overflowing (ref. 23,
p. 4).
52
4.1.4.2
4.1.4.2.1 Toxicity/Persistence/Bioaccumulation Factor
Table 7
Environmental Threat Waste Characteristics
Hazardous
Substance
Source
Attribution
Arsenic
Persistence
(River)
Bioaccumulation
(Fresh water)
Factor
Value
Reference
1,2
10
1
500
5,000
B-2
Beryllium
1
NA
1
50.0
---
B-3
Cadmium
1
1,000
1
5,000
5 x 10
Chromium
1
100
1
5
500
B-5
Cobalt
1
NA
1
5,000
---
B-6
Copper
1,3
100
1
50,000
5 x 10
1
NA
1
50,000
---
B-13
1,2
10
1
500
5,000
B-14
Thallium
1
1
1
500
500
B-18
Zinc
1
10
1
500
5,000
B-20
Iron
1,2
10
1
0.5
5.0
B-12
1,2,3
10
0.4
0.5
2.0
B-18
Manganese
Nickel
Sulfur/Sulfate1
1
Ecotoxicity
6
6
B-4
B-6
881,100 + 202,500 + 8,800,000 = 9,883,500
The hazardous waste quantity factor value assigned for the environmental threat is 1,000,000 (ref. 1, Table 2-6).
53
4.1.4.2.3 Waste Characteristics Factor Category
Multiplying the ecotoxicity/persistence factor value for copper of 100 by the hazardous waste quantity Factor
8
value of 1,000,000 equals 1 X 10 . Multiplying this value by the bioaccumulation factor of copper of 50,000 to
12
produce 5 x 10 (ref. 1, Section 4.1.3.2.3). This value receives a waste characteristics factor category value
of 1,000 for the environmental threat (ref.1, Table 2-7).
Waste Characteristics Factor Category Value: 1,000
54
Targets
4.1.4.3
Environmental Threat Targets
Actual Contamination
Level I
As shown by Table 8, the concentrations of several of the hazardous substances in the observed release
documented by the 1981 to 1983 USGS sampling are greater than the freshwater Ambient Water Quality Criteria
(AWQC) presented in reference 2. These concentrations subject the environmental threat targets in Leviathan
and Bryant creeks, downstream to sampling Station 26, to Level I actual contamination (ref. 1, Section
4.1.4.3.1.1).
Table 8
Surface Water Samples Documenting an Level I Concentrations for the
Surface Water Environmental Threat
Sample
Station and
Date
Dissolved Constituents (in milligrams/liter)
As
Cd
Cr
Cu
Ni
Zn
Ref.
Background Samples
1
3/26/82
0.009
NR
<0.010
<0.010
0.100
0.004
10, p. 25
8/11/82
0.004
<0.001
<0.010
<0.010
<0.100
0.008
10, p. 25
3/25/82
0.003
<0.001
<0.010
0.020
0.100
0.006
10, p. 30
11 3/25/82
0.006
<0.001
<0.010
NR
0.100
0.007
10, p. 32
7
Contaminated Samples
8
3/25/82
0.034
0.006
0.050
0.510
0.700
NR
10, p. 31
8/11/82
0.040
NR
0.090
NR
2.400
NR
10, p. 31
10 3/25/82
1.700
0.025
0.200
1.400
1.400
0.300
10, p. 31
8/12/82
0.038
NR
0.070
NR
2.200
NR
10, p. 32
12 3/24/82
1.400
0.019
0.160
1.200
1.200
0.260
10, p. 33
8/12/82
0.001
NR
0.140
NR
2.300
NR
10, p. 33
17 3/24/82
0.600
0.012
0.120
0.880
0.900
0.190
10, p. 35
8/11/82
0.064
NR
0.050
NR
0.900
NR
10, p. 35
26 3/24/82
0.130
0.003
<0.010
0.240
0.300
0.057
10, p. 38
8/20/82
0.003
<0.001
0.070
0.300
0.500
0.088
10, p. 39
AWQC (fresh)
0.190
0.0011
0.011
0.012
0.160
0.110
2
Key:
As, arsenic; Cd, cadmium; Cr, chromium; Cu, copper; Ni, nickel; Zn, zinc
NR = not reported
Bold values are the farthest downstream samples that exceed the Ambient Water Quality Criteria (AWQC) for freshwater
for each constituent.
Station numbers (except for Station 26) shown on Figure 1.
55
Targets
Before 1954 and the beginning of open pit mining, the entire lengths of Leviathan Creek and Bryant Creek were
habitat for the Lahontan cutthroat trout (Oncorhynchus clarki henshawi) (ref. 19, p.1; ref. 20, p. 2; ref. 22, p.
1). The trout is a federally designated threatened species (ref. 24, p. iii). In March 1999, a fish sample collected
from Leviathan Creek upstream of the mine was subjected to mitochondrial DNA analysis (ref. 28, pp. 2 thru
5). Results indicated that habitat for the Lahontan cutthroat trout still exists in upper Leviathan Creek (ref. 28,
p. 1). Even though the trout is no longer found in lower Leviathan Creek and Bryant Creek, this portion of the
in-water segment has been evaluated as habitat because the AMD from Leviathan Mine resulted in destruction
of this habitat (ref. 20, pp. 2, 3)
The sensitive environments rating value assigned for habitat known to be used by a federally designated
threatened species is 75 (ref. 1, Table 4-23). Therefore, the habitat for the Lahontan cutthroat trout within the
boundaries of the observed release to Leviathan and Bryant creeks receives a Level I concentrations factor value
of 750 (75 x 10) (ref. 1, Section 4.1.4.3.1.1).
Level II
Evidence also indicates that actual contamination extends into the East Fork Carson River. The fish kills reported
in 1952 and 1959 resulting from the release of slugs of AMD from the mine to Leviathan Creek impacted the
surface water down to, and including, the East Fork Carson River (ref. 5, pp. 2-3, 2-4 and 2-34; ref. 15, pp. III2 and III-6). Reports state that the 1959 release destroyed aquatic life along a 10-mile stretch of the Carson
River (ref. 5, pp. 2-3 and 2-4; ref. 15, p. III-6). In 1969, biologists from California and Nevada observed
discolored water and sediment in the East Fork Carson River at the mouth of Bryant Creek, and found that
bottom fauna had been adversely impacted by inflow from Bryant Creek (ref. 23, p. 14). Subsequent to the
construction of the Pollution Abatement Project, turbid water and yellow-orange precipitates have been observed
entering the East Fork Carson River during spring runoff, when the evaporation ponds are overflowing (ref. 23,
p. 4).
The East Fork Carson River currently supports populations of Lahontan cutthroat trout (ref. 24, pp. 11, 12, E-2).
However, because Level I concentrations have already been assigned to the former Lahontan cutthroat trout
habitat in Leviathan and Bryant creeks, the Level II concentrations factor is assigned a value of 0.
Sensitive Environments Target Factor Category Value: 750
Environmental Threat Score: 60
56
SE-General Considerations
5.0 SOIL EXPOSURE PATHWAY
The soil exposure pathway was not scored because no residences, schools, or regularly occupied
structures are known to be within 4 miles of the mine (ref. 9, p. 35).
57
Air-General Considerations
6.0 AIR PATHWAY
The air pathway was not scored because no residences, schools, or regularly occupied structures are
known to be within 4 miles of the mine (ref. 9, p. 35).
58

NPL-U30-2-9-R9 LEVIATHAN MINE Contact Person: Carolyn Douglas, EPA Region IX

Transcription

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